APS NewsA P S N E W SJUNE 1997 THE AMERICAN PHYSICAL SOCIETY VOLUME 6, NO 6

Try the enhanced APS News-online: [http://www.aps.org/apsnews]

IN THIS ISSUE

APS Online Journals ...................................................................................... 1Highlights from Kansas City ........................................................................... 1Career Task Force Makes Recommendations to APS Council ...................... 1Four Corners Section Established by Council ................................................ 1Council Statements Endorsed ........................................................................ 2NSF Faculty Early Career Development Program .......................................... 3Physics History on the Web............................................................................ 3IN BRIEF ........................................................................................................ 3Opinion ........................................................................................................... 4The Federation of Materials Societies ............................................................ 7DCMP and DMP Celebrate 50 Years .............................................................. 7Nominations for 1998 APS Prizes and Awards............................................... 7The Back Page ............................................................................................... 8APS Meeting News ................................................................................. InsertThe Campaign for Physics Update .......................................................... Insert

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reer-oriented programs with the AIPCareer Services Division; formulatinga long-term strategy to address careerand professional development issues,incorporating existing elements of theAPS as well as new ideas and programs;and identification and assistance in theimplementation of new programs toeffectively serve the physics commu-nity in dealing with career issues.

First and foremost, the task forcedetermined that the APS must be con-cerned with career and professionaldevelopment issues at all levels, includ-ing not only PhDs, but also Master’sdegree recipients, bachelor-level physi-cists, and mid-career physicists facedwith career changes, voluntary or other-wise. While acknowledging that theneed to increase the exposure of facultyand students to different career options

Career Task Force Makes Recommendations to APS CouncilThe APS Task Force on Careers and

Professional Development pre-sented its final report andrecommendations to the APS Councilin April. Chaired by Diandra Leslie-Pelecky (University of Nebraska,Lincoln), the task force was created lastyear in response to concerns over thechanging situation for employment ofphysicists. “The Task Force was askedto take a long-range approach andthink of ways that the APS could stimu-late improved preparation andbroadened career options for physi-cists,” said Barrett Ripin, APS AssociateExecutive Officer. “We are pleased thatdid just that,” he said.

The charge to the task force includedadvising the APS on efficient and ef-fective mechanisms for coordinatingand integrating the existing Society ca-

has been recognized by the APS and AIPthrough numerous programs, the taskforce found that these programs do notcurrently reach as many members as theycould, and called for a continuation ofefforts to obtain outside funding for suchactivities.

Developing a workshop designed toeducate faculty about the changing jobmarket, was another recommendation.Suggested contents for workshops, tobe presented at APS meetings, included

Members To Vote on Proposed Amendment toAPS Mission Statement

At its April meeting, the APS Council approved a proposed amendment to theAPS mission statement. The proposed revision will appear on the election ballot thissummer for APS members to vote on its adoption. The amendment — actually apreamble — to the APS objective is motivated by a desire to ar ticulate theorganization’s concern for science education and public affairs issues, and to ex-pand the objective to include activities in this area. The text of the proposedamendment is below.

Article II - Objective.In the firm belief that an understanding of the nature of the physical universe will

be of benefit to all humanity the objective of the Society shall be the advancementand diffusion of the knowledge of physics.

The Campaign fThe Campaign fThe Campaign fThe Campaign fThe Campaign for Phor Phor Phor Phor PhysicsysicsysicsysicsysicsUpdaUpdaUpdaUpdaUpdate Insidete Insidete Insidete Insidete Inside

Beginning July 1,1997, APS

members may enteran online-only one year subscriptionto Physical Review Letters or any sec-tion of the Physical Review for only $25each. In addition, APS members whohave a paper subscription to PhysicalReview Letters or any section of thePhysical Review will get a free subscrip-tion to the online version of thecorresponding journal.

APS members who have a papersubscription to either part of PhysicalReview B (B1 or B15) will get a freesubscription to the online version of theentire Physical Review B (B1 and B15),as well as Physical Review B-Rapidsonline. APS members who have a papersubscription to either part of PhysicalReview D (D1 or D15) will get a free sub-scription to the online version of theentire Physical Review D (D1 and D15).

To take advantage of this offer, addthe online journals selected on yourrenewal invoice and remit the appro-priate payment. Please take the time toprint your email address legibly in thespace provided on the invoice so thatwe may notify you by email as to how

you may register online and select yourpersonal username and password forthe online journals. We must have yourcorrect email address to proceed.

Currently available online are Physi-cal Review A, B-Rapid Communications,C, and D, as well as Physical Review Let-ters. The APS is aiming to release theonline version of Physical Review B andPhysical Review E in July 1997, and Re-

views of Modern Physics in early 1998.As the APS continues research into thelatest and most effective online deliverymode to better serve the diverse needsof the physics community, new featuresand delivery schedules will be incorporatedinto all online journals. CD-ROM versionsof APS online journals are currently pricedat $25 per disk and will be announced asthey become available during the year.

For the latest journal subscriptionrates for all APS research journals andother APS membership benefits, pleasesee the 1997-98 Guide to Member Ser-vices enclosed with your renewalpackage, or visit the APS home page athttp://www.aps.org, or send an emailto membership@aps.org. Inquiries mayalso be directed to phone: (301)209-3280 or fax: (301)209-0867.

Approximately 4,400 physicistsconverged on the Kansas City

Convention Center in Kansas City,Missouri, 17-21 March, for the Society’sannual March Meeting. Over 4,500technical papers were presented,mostly on topics in condensed matterand materials physics, as well as relatedfields. APS units represented at themeeting included the Divisions ofBiological Physics, Chemical Physics,Condensed Matter Physics, FluidDynamics, High Polymer Physics, andMaterials Physics. Recently establishedTopical Groups on Statistical andNonlinear Physics and Magnetisim andits Applications as well as the Forum

on Industrial and Applied Physics werealso represented.

Among the technical highlights werenumerous sessions on carbonnanotubes, as well as the measurementof atto-Newton forces using magneticresonance microscopy, the latest onswitchable mirrors, the observance ofself-organized criticality in mammalianbrain cells, the development of x-raymicroprobes, and splitting DNA usingoptical tweezers. There was also a spe-cial session featuring lectures by thisyear’s Nobel Prize winners.

Nontechnical highlights included asession on the challenges of handlingnuclear waste, a look at entrepreneurial

Highlights from Kansas City March Meeting

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physics, and a humorous series of lec-tures exploring the “lighter” side ofscience, the third such session orga-nized by the APS Topical Group onInstrument and Measurement Sciencesince 1994. The meeting also featuredcelebrations of the 100th anniversaryof the discovery of the electron andthe 50th anniversary of the transistor.

Prizes and Awards. The traditionalceremonial session for the bestowal ofprizes and awards was held Mondayevening, followed by a receptionhosted by APS President D. AllanBromley (Yale University). Ten APS

Physical Review Online Subscriptions Only $25 for APS MembersSpecialOffer

The Four Corners Section, the firstnew APS regional section since 1976 wasestablished by unanimous vote of APSCouncil at its April 19 Meeting, subjectto ratification of its bylaws by the APSConstitution and Bylaws Committee. TheFour Corners Section encompasses Ari-zona, Colorado, New Mexico, and Utah.There are over 300 charter members todate. APS members living in the FourCorners area are encouraged to join thenew section by writing it in on their APSinvoice returns. Note that Section mem-berships are free to APS members.

Interim Four Corners Section Offic-

Four Corners Section Established by Councilers, elected by an organizational groupmeeting in Albuquerque on March22nd, are: Chair, Bill Evenson (BYU),Chair-elect, J.D. Garcia (U. Of Arizona),Vice-chair, David Wolfe (UNM), Secre-tary-Treasurer, Eric Jones (Sandia), plusmembers-at-large of the ExecutiveCommittee: Brenda Dingus (U. OfUtah), Mariet Hofstee (Colorado Sch.Of Mines), Andrea Palounek (LANL),Michael Petras (Motorola-Tempe).Harry Lustig, APS Treasurer emeritusand now living in Santa Fe, played aleading role in the new section’s for-mation.

APS News June 1997

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APS NewsCoden: ANWSEN ISSN: 1058-8132Series II, Vol. 6, No. 6 June 1997© 1997 The American Physical Society

Editor: Barrett H. RipinNewswriter: Jennifer OuelletteProduction: Elizabeth Buchan-Higgins

Adrienne VincentCoordinator: Amy Halsted

APS News (ISSN: 1058-8132) is published 11X yearly, monthly,except the August/September issue, by The American PhysicalSociety, One Physics Ellipse, College Park, MD 20740-3844, (301)209-3200. It contains news of the Society and of its Divisions,Topical Groups, Sections and Forums; advance information onmeetings of the Society; and reports to the Society by its com-mittees and task forces, as well as opinions.

Letters to the editor are welcomed from the membership. Lettersmust be signed and should include an address and daytime tele-phone number. The APS reserves the right to select and to editfor length or clarity. All correspondence regarding APS News shouldbe directed to: Editor, APS News, One Physics Ellipse, CollegePark, MD 20749-3844, email: letters@aps.org.

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Subscription orders, renewals and address changes shouldbe addressed as follows: For APS Members—Membership De-partment, The American Physical Society, One Physics Ellipse,College Park, MD 20740-3844, membership@aps.org. For Non-members—Circulation and Fulfillment Division, American In-stitute of Physics, 500 Sunnyside Blvd., Woodbury, NY 11797.Allow at least 6 weeks advance notice. For address changes,please send both the old and new addresses, and, if possible,include a mailing label from a recent issue. Requests from sub-scribers for missing issues will be honored without charge onlyif received within 6 months of the issue’s actual date of publi-cation.

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APS COUNCIL 1997

PresidentD. Allan Bromley, Yale UniversityPresident-ElectAndrew M. Sessler, Lawrence Berkeley LaboratoryVice-PresidentJerome Friedman, Massachusetts Institute of TechnologyExecutive OfficerJudy R. Franz, University of Alabama, Huntsville (on leave)TreasurerThomas McIlrath, University of Maryland (on leave)Editor-in-ChiefMartin Blume, Brookhaven National LaboratoryPast-PresidentRobert Schrieffer, Florida State University

General CouncillorsDaniel Auerbach, Virginia Brown, Jennifer Cohen, Charles Duke,Elsa Garmire, S. James Gates, Donald Hamann, William Happer,Anthony M. Johnson, Zachary Levine, Paul Peercy, Susan Seestrom,Virginia Trimble, Ronald Walsworth, Sau Lan Wu

Chair, Nominating CommitteeGerard Crawley

Chair, Panel on Public AffairsRobert M. White

Division and Forum CouncillorsFrank C. Jones (Astrophysics), Eric Heller, Gordon Dunn (Atomic,Molecular and Optical), Robert Callender (Biological), StephenLeone (Chemical), Joe D. Thompson, David Aspnes, Lu J. Sham,Zachary Fisk (Condensed Matter), Warren Pickett (Computa-tional), Guenter Ahlers (Fluid Dynamics), James Wynne (Fo-rum on Education), Albert Wattenberg (Forum on History of Phys-ics), Matt Richter (Forum on Industrial & Applied Physics), ErnestHenley (Forum on International Physics), Dietrich Schroeer (Fo-rum on Physics and Society), Andrew Lovinger (High Polymer),Daniel Grischkowsky (Laser Science), Howard Birnbaum (Ma-terials), John Schiffer, Peter Paul (Nuclear), Henry Frisch, GeorgeTrilling (Particles and Fields), Hermann Grunder (Physics ofBeams), Roy Gould, William Kruer (Plasma)

ADVISORS

Sectional RepresentativesJohn Pribram, New England; Peter Lesser, New York; Perry P. Yaney,Ohio; Joseph Hamilton, Southeastern; Stephen Baker, Texas

Representatives from Other SocietiesRonald Edge, AAPT; Marc Brodsky, AIP

Staff RepresentativesBarrett Ripin, Associate Executive Officer; Irving Lerch, Director ofInternational Affairs; Robert L. Park, Director, Public Informa-tion; Michael Lubell, Director, Public Affairs; Stanley Brown, Ad-ministrative Editor; Reid Terwilliger, Director of Editorial OfficeServices; Michael Stephens, Controller and Assistant Treasurer

At its April meeting, the APS Councilapproved a statement calling for

the renewal and enhancement of U.S.neutron scattering facilities by the U.S.government. According to Frank S.Bates, president of the NeutronScattering Society of America, the mostpressing challenges facing the neutronscattering community are reactorupgrades at Brookhaven NationalLaboratory and Oak Ridge NationalLaboratory (ORNL), and construction ofa short pulsed spallation source in thepower range of one measurement. Theseprojects would provide neutronscattering scientists and engineers in theU.S. with capabilities approaching thosecurrently available in Europe. The fulltext of the Council statement follows.

The American Physical Society rec-ognizes the scientific importance ofneutron scattering science as a key areaof endeavor for physics, chemistry,materials and biomedical research. Formany decades, the United States waspreeminent in neutron scattering sci-ence with state-of-the-art reactor andspallation neutron facilities. Today wehave lost that preeminence and couldwell cease to be a major player in thisfield — in spite of its centrality to fun-damental scientific studies as well asmany areas of science important to

In April, the APS Council approved astatement endorsing the Comprehen-

sive Test Ban Treaty (CTBT), draftedby the APS Panel on Public Affairs(POPA). The statement was promptedby concern that failure of the U.S. toratify the treaty would tempt other na-tions to begin testing nuclear weaponsagain, and greatly weaken the politicalrestraints on those states that do notcurrently have nuclear weapons. TheJASON Group, an independent groupof senior non-government scientiststhat advises the U.S. Department ofEnergy on national security issues, hasreleased a report concluding thatnuclear testing will not be needed, pro-vided that a viable stockpilestewardship program is in place.

The CTBT has now been signed bythe five nuclear weapons states and 132other nations, and is expected tostrengthen the nuclear Non-Prolifera-tion Treaty, signed by more than 175nations agreeing not to develop or ac-quire nuclear weapons. According toPOPA Chair Robert White, the treatywill also strengthen nuclear nonprolif-eration by raising the technical andpolitical barriers for non-nuclear weap-ons states to develop nuclear weapons,and for the three primary nuclear weap-ons states to develop more powerfulfission weapons. In addition, the CTBTwill strengthen monitoring down toone kiloton or lower in a growing num-ber of locations.

The full text of the APS Council state-ment follows.

On September 10, 1996, the UnitedNations overwhelmingly approved theComprehensive Test Ban Treaty (CTBT),a treaty ending all nuclear testing, ofany yield, at any location, for all time.The United States, all other declarednuclear weapon states, and a growingmajority of the world’s nations have

Passage of Nuclear Test Ban Treaty

Neutron Scattering Facilitiesnational needs.

The critical need for modern neu-tron scattering facilities has been welldocumented and recommendationshave been made to upgrade U.S. capa-bilities, but the needed developmentshave not come to fruition. If our neu-tron scattering facilities are notenhanced soon, this field will sufferdamage to its research programs thatwill take decades to rebuild. As U.S.leadership is lost, important technolo-gies that depend upon the knowledgegained from neutron scattering studies— including the development of newpolymers, superconductors and chemi-cal catalysts, and the use of neutronprobes to study the stresses and impuri-ties in materials that affect theperformance and safety of structuressuch as bridges and aircraft — are in-creasingly at risk. In addition, we areno longer able to supply our growingneeds for neutron-producedradiopharmaceuticals.

The Council of the American Physi-cal Society stresses the critical importantof neutron scattering to a wide spec-trum of scientific and technical fieldsand urges the U.S. government to pro-ceed rapidly with the renewal anddevelopment of national reactor andspallation neutron facilities.

At its April meeting, the APS Councilapproved a statement in support

of the open exchange of scientific data,in response to recently proposedchanges to laws that protect intellectualproperty, which could translate intooverly restrictive policies governing“fair use” exceptions for the contentsof databases. Fair use exceptionsenable scientists and educators to usecopyrighted materials, such aspublished research papers, for free orat reduced costs, if the information isused for research, teaching or otherspecific purposes.

Specifically, the proposed lawswould enable database vendors tocharge scientists and educators at com-mercial rates for access and even, insome cases, to maintain a monopolyon publicly funded research data. Ac-cording to R. Stephen Berry, a professorof chemistry at the University of Chi-cago who chaired a National ResearchCouncil committee appointed to reporton the issue, it is feared that such re-strictions could greatly inhibitcollaborative scientific research projectsthat depend on constantly updated in-formation. Limiting access to data

would be especially damaging to sci-ences concerned with internationalissues such as global change and theenvironment, the prevention and treat-ment of disease, and biodiversity, eachof which requires the open exchangeof globally compatible data among sci-entists in both rich and poor nations.

Last year the World Intellectual Prop-erty Organization (WIPO), anintergovernmental organization affiliatedwith the United Nations that promotesthe protection of intellectual property,introduced a draft treaty on databasesand intellectual property at a diplomaticconference. Although the treaty was re-jected, WIPO may propose a new versionlater this year without “fair use” excep-tions for scientists and educators.

If WIPO were to endorse such atreaty, it would establish new interna-tional norms that in turn would obligatethe U.S. and other signatory countriesto amend their own intellectual prop-erty laws, the NRC committee reported.The Commission of the European Com-munities (CEC), which sets economicpolicies for its member states, adoptedan intellectual property directive thatfails to provide adequate fair use ex-ceptions in February 1996. U.S.legislators introduced a similarly

Council Statements Endorsed

now signed that treaty. Although the dateat which the CTBT will enter into force isnot yet certain, the treaty is of extraordi-nary importance to the United States andto the future of all humankind.

The CTBT, the culmination of over40 years of effort, ends the qualitativearms race among the nuclear states andis central to future efforts to halt thefurther spread of nuclear weapons. Thepromise to negotiate and put into forcea CTBT was an essential pre-conditionto achieving an indefinite extension ofthe Non-Proliferation Treaty (NPT) in

Open Flow of Scientific Information

May 1995. Ratification of the CTBT willmark an important advance in unit-ing the world in an effort to containand reduce the nuclear danger.

Having been the first country to de-velop nuclear weapons, having been amajor participant in the nuclear armsrace of the Cold War, and havingplayed a leadership role in the NPT ex-tension and the CTBT negotiations, itis appropriate and imperative that theUnited States ratify the ComprehensiveTest Ban Treaty at the earliest possibledate. The Council notes that detailed,fully informed technical studies haveconcluded continued nuclear testing is

not required to retain confidence in thesafety and reliability of the remainingnuclear weapons in the United States’stockpile, provided science and technol-ogy programs necessary for stockpilestewardship are maintained. This con-clusion is supported by both the seniorcivilian and military officials respon-sible for U.S. national security.

The Council of the American Physi-cal Society, r epresenting 41,000academic, industrial and laboratoryphysicists, endorses the CTBT, includ-ing its extensive technical andprocedural provisions to verify compli-ance with treaty requirements.

restrictive bill in the House of Repre-sentatives in May 1996.

“Science is a cumulative process, andlaws that inhibit the flow of scienceinformation by making it unaffordablewould force cutbacks in research aswell as significantly slow our progressin science and technology,” said Berry.“These laws are flawed from an eco-nomic point of view because of thepossibility that unrestricted monopo-lies may result, particularly by peoplewho have no direct concern for thepublic benefits of science.”

The full text of the statement fol-lows.

The open flow of scientific data isessential to the progress of science. TheAmerican Physical Society is thereforegreatly concerned by proposed legisla-tion and treaties which would impose,through copyrighting of data bases, se-vere restrictions upon the fair use ofscientific data, the generation of whichwas supported by public funds. The So-ciety supports a balanced approach tocopyright laws, which maintains thetraditional principles of fair use and ofexpiration of copyright after a reason-able period, while still protectingintellectual property rights of authorsand publishers.

June 1997 APS News

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IN BRIEF• Donald H. Weingarten of IBM/Yorktown Heights has been awarded the

APS 1997 Aneesur Rahman Prize for Computational Physics. His citationreads, “For his seminal work on lattice quantum chromodynamics, in-cluding algorithmic innovations, massively parallel computer softwaredevelopment and hardware implementation that led to calculations ofhadron masses and the mass and decay couplings of the scalar glueball.”A native of Massachusetts, Weingarten received his PhD from ColumbiaUniversity in 1970 and subsequently held research positions at Fermilab,the University of Copenhagen, the University of Paris, and the Universityof Rochester. In 1976 he joined the faculty of Indiana University, leavingin 1983 to join the research division of IBM/Yorktown Heights, where hehas worked ever since. The Rahman Prize was established in 1992 withsupport from IBM and Argonne National Laboratory. It is intended torecognize and encourage outstanding achievement in computational phys-ics research. The Rahman Prize will be presented to Weingarten at thePC’97 Meeting to be held August 25-28, 1997 in Santa Cruz, CA.

• The APS Committee on the Status of Women in Physics and the Forum onHistory of Physics are co-sponsoring the creation of an historical archive,compiling an electronic collection of citations of women who have madeoriginal and important contributions to physics in the 20th century. Theproject is part of plans for the celebration of the 1999 Centenary of theAPS. Nina Byers, UCLA, is directing the project. The APS Council’s Execu-tive Board has allocated funds to help pay for the project. UCLA, wherethe web-site is located, has also provided funds. There turned out to befar more contributions than even the originators of the project realized.So far 167 scientific biographies have been collected and 29 are ready forviewing on the project’s Website (http://www.physics.ucla.edu/~cwp).Citations include brief descriptions of the contributions documented withreferences to published papers, as well as some biographical informa-tion.

• The recent energy study conducted by the APS Panel on Public Affairs,which provided the background materials for the APS Council statementon energy (“Energy: the Forgotten Crisis”), is now available on the WorldWide Web [http://www.aps.org/public_affairs/popa]. Included are textof background papers written by individual members of the POPA Sub-committee on Energy and Environment. At this point, they reflect theviews and perspectives of the authors and not necessarily those of POPAor the APS. Topics include a summary of the current energy situation; alook at kinds of energy supplies, such as fossil energy, nuclear fissionenergy and renewable energy; an overview of energy use trends, andtransportation and energy issues; and other considerations, including cli-mate change, DOE’s R&D priorities, pedagogic energy modeling, andenergy units. The summary of the energy study is available at the samesite.

• The National Science Foundation is instituting new merit review criteriafor all grant proposals beginning October 1, 1997. The new criteria weredrafted by a special task force formed by the NSF and the National Sci-ence Board to suggest changes to the review criteria, which have notbeen revised since 1981. The task force presented draft criteria to thescientific and engineering community for public comment in November1996, and the subsequent revised version was approved by the NationalScience Board in March. Specifically, the task force reduced the numberof criteria reviewers must consider from four to two: the intellectual meritof the proposed activity, and its broader impacts. Each of the criteria hasa set of related questions to help reviewers evaluate the proposals. Re-viewers are asked to provide separate comments for each criterion, asingle composite rating of the proposal, and a summary recommendationthat addresses both criteria. The task force believes that “adoption of thenew criteria will facilitate, clarify, and simplify the proposal evaluationprocess.”

• Two APS fellows were among seven winners of the 1996 E.O. LawrenceAward, established in 1959 to honor the memory of the late Dr. ErnestOrlando Lawrence, who invented the cyclotron and after whom two majorDOE laboratories are named. The award is given in seven categories foroutstanding contributions in the field of atomic energy. The awards willbe presented at a ceremony in Washington, DC, this spring; winners willeach receive a god medal and $15,000. APS member Thomas H. Dun-ning, Jr., a theoretical chemist at Pacific Northwest National Laboratory, isbeing honored in the Chemistry category for his electronic structure cal-culations on molecules, which has been applied in laser technology,combustion chemistry and environmental chemistry. Sunil K. Sinha, anengineer at Argonne National Laboratory, will receive the award in theMaterials Research category for developing new techniques for using xrays and neutron scattering to learn new details about the structure ofmany materials.

discussion of the skills necessary fordifferent careers and how to providestudents with opportunities to acquirethem; mechanics of helping studentsfind a non-academic job; and informa-tion on successful programs at otherschools. While AIP currently presentscareer workshops, the task force notedthat these are directed towards studentsand do not contain materials specificto the needs of the faculty member’srole as mentor. Sessions directed to-ward faculty have instead generallyfocused mostly on statistics. Strong in-put from industrial scientists was alsodeemed critical to ensure the relevanceof the workshop material.

In addition, the task force suggestedthat the APS offer short courses onmanagement skills, communicationskills, and other helpful skills whichmight be of interest to APS members.The APS might also offer a short courseon pedagogy for physics faculty andgraduate students who are teaching orinterested in pursuing a teaching ca-reer. The task force also suggesteddevelopment of two short videotapes,one for undergraduate students and an-other for graduate students, to beprovided to physics departments acrossthe country. Finally, the task forcecalled for continued efforts to compilestatistical information trackingpostdoctoral fellows. This would hope-fully help answer questions aboutwhere they eventually find jobs.

The task force also recommendedthat an APS committee be given theprimary responsibility for career issuesand implementing its recommenda-tions, preferably one drawing itsmembers from academia, industry andgovernment to ensure balanced repre-sentation. The APS is currently looking

into the best way to establish this com-mittee. The task force acknowledgedthe involvement of several APS forumsin this area and emphasized that thecommittee assignment is not meant todiscourage forums from continuing toparticipate; rather, it will help central-ize information for members andprovide coordination among interestedparties. Over the next year, the TaskForce will continue its work, but shiftemphasis towards implementing its rec-ommendations.

The members of the task force are:Diandra Leslie-Pelecky, Chair (Univer-sity of Nebraska), Tony Nero (LawrenceBerkeley National Laboratory), RobertKwasnick (General Electric), Steven J.Smith (NCAR), Glen Crawford (StanfordLinear Accelerator Center), RobertBartolo (University of Maryland), Pe-ter Abbamonte (University of Illinoisand Argonne National Laboratory), andPeter Wolff (MIT). The senior APS ad-visor to the task force is Barrett Ripinand Arlene Modeste is staff liason. Alsocontributing to the discussions were EdGoldin of AIP’s Career Services, RomanCzujko of AIP’s Employment and Sta-tistics Division, APS Executive OfficerJudy Franz, APS Treasurer TomMcIlrath, AAPT Executive Officer Ber-nard Khoury, Kevin Aylesworth of theAPS Education Division and SherriePreische of APS Special Projects.

A full copy of the task force report maybe viewed through the APS home page[aps.org] under the Career and Employ-ment button or a hard copy may beobtained by contacting Arlene Modeste,APS, One Physics Ellipse, College Park,MD 20740; phone: (301) 209-3232;email: modeste@aps.org.

Career Task Force (Continued from page 1)

Proposals for FY98 are now beingconsidered for the Faculty Early CareerDevelopment (CAREER) program spon-sored by the National ScienceFoundation. CAREER is a Foundation-wide activity that supports junior facultywithin the context of their overall ca-reer development. It combines in a singleprogram the support of research andeducation of the highest quality and inthe broadest sense. The program empha-sizes the importance that the NSF placeson the early development of academiccareers dedicated to stimulating the dis-covery process in which the excitementof research is enhanced by inspiredteaching and enthusiastic learning.

Furthermore, beginning in 1997, theNSF will select up to 20 nominees fromamong the most meritorious first-year

NSF Faculty Early Career DevelopmentProgram

awardees supported by the CAREERprogram for the Presidential Early Ca-reer Awards for Scientists and Engineers(PECASE). PECASE awards recognizeoutstanding scientists and engineersshow exceptional potential for leader-ship at the frontiers of knowledge earlyin their careers. It is the highest honorbestowed by the U.S. Government onscientists and engineers beginning theirindependent careers.

The application deadline for theCAREER program is July 22, 1997, sig-nificantly earlier than last year’sdeadline. Those interested in applyingmay find additional information on theNSF home page [http://www.nsf.gov]or the Career Program Announcement[http://www.nsf.gov/pubs/1997/nsf9787/nsf9787.txt].

Physics History on the WebThe AIP Center for History of Physics announces two new science history

exhibits on the World Wide Web:Discovery of the Electron. This year is the centennial of the experiments

that led J.J. Thomson to announce the discovery of the first fundamental sub-atomic particle. The history of this famous advance can be reviewed at the Website below. A text based on recent historical studies is accompanied by photo-graphs, animated diagrams, quotes, and clips of Thomson’s voice. Science teachersand students in particular should profit from viewing the site. [http://www.aip.org/history/electron]

Online Einstein Museum. The Center for History of Physics also offers alarge Web site giving a guided tour through the life of Albert Einstein. Numerouspictures along with quotes and voice clips illustrate an authoritative text byhistorians. The viewer can click on menu items dealing with Einstein’s formativeyears, his revolutionary works such as relativity, his world fame (with periodcartoons), the nuclear age, and many other subjects. It is organized with anindex of topics and features, a chronology of basic facts, and links to muchadditional information on the Web about Einstein’s life and science. [http://www.aip.org/history/einstein]

Prudenceby Robert Garisto

There once was a prof lacking prudenceWho studied a black hole’s refusance

To show hide or hairOf what he’d tossed there,

Including the last of his students!

APS News June 1997

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OPINIONLETTERSAPS VIEWS

What Have You Done for Me Lately?by Irving Lerch, APS Director of International Scientific Affairs

It may be discomforting, but it’s sometimes necessary totake a critical look at our cherished beliefs and veneratedrelationships and ask, “What have you done for me lately?”

Over the past few years, perhaps in response to the fal-tering public support for science, a great deal ofsoul-searching has taken place as various panels have re-viewed the status and value of the international scientificunions and the whole panoply of domestic and foreign or-ganizations which comprise the global scientific enterprise.And in these days of budgetary pain and uncertainty, it’s easy to sniff waste andinefficiency, and to conclude that our institutions have failed us. So,disintermediation is in and soft-minded accommodation is out. To use the jar-gon of our era, it’s time to hang tough and play a zero-sum game.

Consider the opening paragraph of a report on a meeting on internationalcooperation on research in science, engineering and medicine, held in Bellagio,Italy in the fall of 1995, which commented, “The institutions designed to serveglobal science since the end of World War II are not keeping pace with thechanges sweeping science and technology.” In short, everyone is quite sure thatour institutional mechanisms for international science are inadequate, but incre-mental change and not revolution is preferred.

In a review of the International Union of Pure and Applied Physics (IUPAP) afew years ago, the APS Executive Board concluded that few physicists knewanything about IUPAP, its purpose, or its value. A minority of physicists wereaware that IUPAP sponsorship for conferences was essential if they were to usegrant funds to attend. Some were aware that ICSU provisions for the free circu-lation of scientists were important to open conferences to attendees whose politicalorigins would other bar them. And a very tiny group actually participated in thecommissions of the Union. One wag suggested that this ignorance might be agood thing, since it was proof that IUPAP was not disruptive and may actuallybe contributing in some quiet way to the workings of international physics.

But doing no harm is no longer sufficient justification for spending money.The Bellagio panel generated a long list of generic ills broadly applied to manydifferent kinds of international organizations: deficiencies in governance andstaffing, narrow participation and focus, lack of resources, institutional rigidityand inefficiency. For example, the panel noted that, “Most institutions ... focustheir efforts on university and government scientific capacity. As an economicsector, the private sector has not been recognized as a critical player in globalscience and rarely has a seat at the collaborative table.”

Only in the past few years has the APS itself acknowledged such deficienciesand sought to correct them. But APS is a membership organization whose valid-ity and viability derives from its grass roots. This is not true of the internationalscientific unions, whose rigid structure and glacial pace of doing business makesit difficult to institute new programs and organizational change. Yet for threegenerations, when the world was cemented into the post-War political order,this fixity was seen as a virture by many.

What other structures are open to us? The U.S. has increasingly turned tobinational foundations to promote scientific collaborations. Establishments suchas the U.S.-Korea Science and Technology Forum and the German-AmericanAcademic Council Foundation were created at the highest political level andthen launched as private initiatives. Because of their lofty origins, they readilypromote collaborations across institutional and disciplinary divisions, bringingtogether a broad collection of government, industrial, policy, technical and ad-ministrative experts. Such fora are difficult to organize on a multinational scale,In fact, experience shows that as the international scope broadens, the depth ofoutcome becomes more shallow.

Both the APS and the Korean Physical Society are sponsors of the U.S.-Koreaforum. The membership society is an engine which can revitalize the interna-tional physics enterprise. As grass-roots organizations charged with serving theneeds of their members, such societies are most sensitive to the prevailing windswhich alter the course of science. This sense of change coupled with a firmcommitment to science are the essential ingredients for all the organizations inthe global physics enterprise.

IUPAP, on the other hand, is insulated from the societies by the nationalacademies and research councils of its members. While the APS has statutorypositions on the U.S. Liaison Committee (USLC) for IUPAP, it must act throughthe National Research Council’s Board on Physics and Astronomy in its dealingswith the Union. Nonetheless, the APS and other participating societies havemoved to invigorate the USLC by taking a more active role in its deliberations. Inreturn, the IUPAP Executive Committee is seeking tighter connections to na-tional and regional societies.

To explore the growing list of critcal issues confronting the international scien-tific community, APS President Allan Bromley, Past President Robert Schrieffer, andPresident-Elect Andrew Sessler have called for a small consultative meeting thisOctober of the largest membership societies (Japan, Germany, United Kingdom,China, and the U.S.), as well as the five regional societies (Europe, Latin America,Asia-Pacific, Africa and the Russian Federation). While the focus of the meeting willshift among specific issues — such as electronic publishing, education, sciencepolicy, and capacity building — the underlying question will be how the interna-tional community can best organize itself to confront these and future concerns.

We will soon confront the issue of whether to work for change from within or tothrow over the existing order and start anew. What we eventually decide couldresonate for another three generations, and it would be wise for all of us to beheard.

It was a pleasure to see PeterAbbamonte show the best qualities ofa real physicist. I commend him for hisanalysis and his personal strength (“TheBack Page,” APS News, April 1997). Aminor historical note, though: It is nottrue that the implications of exponen-tial growth of the number of physicistswent unrecognised for 80 years. Theremay also have been earlier instances,but I know that in the job crunch thatoccurred after the ’68-69 downturn infunding, the propensity of systems tochange from exponential growth to an“S”-curve as resource limits are ap-proached was noted and discussed inPhysics Today and elsewhere.

I also recall a brief article (or per-haps letter) wherein a recent Ph.D.presented a sequence of letters osten-sibly seeking employment outside ofphysics. The first indicated his full edu-cational background, followed by areply rejecting him on the grounds ofbeing overqualified for the job. In thesecond, third and fourth letters, he lim-ited his resume to M. Sc., B. Sc. andhigh school diploma, in sequence, andwith appropriately declining quality oflanguage, with the same result. The

Perspectives on the Job “Crunch”

The April 1997 issue of APS Newscontained a well-written “Back Page”article on the employment crunch foryoung PhDs. Not included was thesimple fact that the field of physics asone of productive employment did notexist before World War II. The reasonfor this is obvious: no product that re-quired those skills for fabrication and/or sales existed. The field is sufficientlydifficult — requiring math as its languagebefore a beginning can even be made— that anyone who concentrated on itas a field of learning in college must have

final letter, written in the vernacular,merely indicated that he was qualifiedto drive a truck, which did produce anemployment offer. (I may have the de-tails wrong after a quarter of a centuryor so, but this catches the tenor.)

So while our younger colleaguesmay not be standing on the shouldersof giants in this regard, they should atleast be aware that they can (and do)benefit from those that have gone be-fore them.Terry GoldmanLos Alamos, New Mexico

Please congratulate PeterAbbamonte for his delightfully funnyBack Page article entitled “The Crunch.”At first I was infuriated by his naiveattitude of self-importance, but once Irealized it was an April Fool’s article, itmade my afternoon! The very idea thatsomeone could be that whiny and ig-norant was hilarious. I especially lovedthe “garbage can scene” and the ideathat physicists breed exponentially likerabbits. What an imaginative gag!Katherine RawlinsUniversity. of Wisconsin-Madison

After reading them once, and withno reflection, I thought the APS goalsoutlined by APS President Judy Franz(APS VIEWS, April 1997) all reasonableand worthwhile. I was especiallypleased to see phrases like “through-out the world.” But Goal # 8 struckme as especially important. I wouldthink it an important goal at any timeof the world (from the time of Thales

been independent of the job market, ornot conscious of the facts of life, one ofwhich is a reliable source of money.

Unfortunately the public, fromwhich all new talent comes, was notmade aware of the real joy found increative activities of the technical sort,and many of us neglected to point themout. Things that demand knowledgeand the ability to search nature withthe tools provided by physics will al-ways be in demand.Carroll B. MillsKenwood, California

We Need an Inclusive Definition for Physicists

of Miletus to the present). Physics is(or ought to be) a fellowship of thosewho have the passion for, and a talentsufficient to add to the knowledge ofour field. Defining the community ofphysicists by exclusion, especially inthese days, is selfish, and like all self-ishness, stupid.Keran O’BrienNorthern Arizona University

June 1997 APS News

5

OPINION

APS members attending the Society’sMarch meeting were provided an

opportunity to attend a newly offeredsession on retirement account planningwhich was led by two skilled and ex-perienced pension benefit and estateplanning advisors. The information theyprovided to the attendees was enlight-ening to say the least. For example,many APS members did not realize thateach year they may be able to use adefined benefit pension plan to shelterup to 100% of self-employment earn-ings including consulting, royalties fromwriting a book, fees for editing or re-viewing, sales from inventions, incomefrom tutoring, honoraria, and other1099 earned income. And, almost allAPS members did not know that thereis a total maximum amount you cansave without penalty as assets in yourretirement account (TIAA, Supplemen-tal TIAA, IRAs and KEOGHs). With therise in the stock market, many physi-cists will easily surpass the limits andwill be in the penalty region. Distribu-tions have to be carefully plannedaround estate tax rules which can claim75-95% of the accumulations.

Qualified Saving Plan

What are the advantages to using aqualified savings plan to shelter earn-ings? First of all, the contributions tothe plan are tax deductible. Second, theinvestment earnings on your contribu-tions are not currently taxable. Third,the eventual distributions may be taxedat favorable rates. For example, if youwere to contribute $10,000 per year toa qualified savings plan earning 8% peryear (net of investment expenses) andif your marginal income tax rate is 40%,then the accumulated savings at retire-ment age would be as follows:

Safeguard that Retirement Account!by Darlene Logan, APS Development Director

As one can see, substantial finan-cial returns are obtained by investinginside the qualified plan. You can alsovary your tax deductible contributionsto the plan from year to year. Further,even when you reach retirement age,you will not need to pay tax on thefull amount of your accumulated sav-ings in your qualified savings plans asyou may “roll” your accumulated sav-ings to an IRA. In effect, your savingscontinue to earn income on a tax de-ferred basis. When the distributions areeventually taken from the IRA, they willbe treated as ordinary income for in-come tax purposes.

Dangers of Over Accumulation inRetirement Accounts and Options

In planning for distributions fromqualified retirement plans and indi-vidual retirement accounts, be awarethat these distributions may be subjectto a number of adverse tax rules. Atdeath, the benefits in such plans maybe subject to the federal estate taxwhich applies to estates exceeding$600,000. Second, the benefits from theplans will also be subject to incometax when received by the beneficiary.Third, excessively large amounts inqualified plans and IRAs, which the IRSdeems as excess accumulations, mayalso be subject to an additional 15%excise tax. The combination of thesetaxes can be over 75% of the

Highlights from Kansas City (Continued from page 1)

prizes and awards were presented, andthe recipients gave lectures on their re-spective award-winning topics atvarious sessions throughout the week.Citations and brief biographical sum-maries of the recipients appeared in theMarch 1997 issue of APS News.

Technical Sessions.

Room-Temperature Mid-InfraredLasers. At two Thursday morning ses-sions, researchers described variousnew designs for mid-infrared lasers,devices that deliver light with a wave-length of 2-6 microns. Since this lightis transparent in the atmosphere, mid-infrared lasers would be ideal fordetecting pollutants, and serving as apart of a collision-avoidance system inautomobiles. Although it has tradition-ally been difficult to produce laser lightin this part of the spectrum, research-ers in the past year have successfullyproduced room-temperature versions.In addition, they are striving to improvethe notorious inefficiency of these de-vices. Steven Pei of the University ofHouston reported details on a brand-new mid-infrared laser design based onantimony.

Chocolate and Shock Absorbers.An electrorheological (ER) fluid is onewhose stiffness can be controlled withelectric fields. Years of research in thisarea have yet to result in practical ap-

plications, partly through a lack of suf-ficient control over the ER process. Anotable exception is the no-fat ERchocolate bar described to the left onpage 4. But this may change soon. At aFriday morning session, Clark Radcliffeof Michigan State University announcedthe development of a feedback con-trol mechanism using laser light tosense the amount of “chaining” amongmolecules in the fluid. One byproductof the precision control of the ER pro-cess itself is a 30-fold increase in theER response time. This should encour-age the advent of ER-basedcomponents for hydraulic valves,clutches, and shock absorbers. More-over, one MSU researcher has indeedbeen studying how ER can be used inthe manufacture of low-fat chocolate.

Compact Discs and Blue Lasers.On Monday morning, Shuji Nakamuraof Nichia Chemical Industries in Japanannounced the development of a room-temperature, continuous-operation,blue-light laser with a much longer life-time than previous devices.Light-emitting diodes, already in use indisplay systems, are efficient produc-ers of light (red and blue) and will soonbe used in automobile brake lights andtraffic lights. For optical storage appli-cations, however, one needs diodelasers. For one thing, the digital versa-tile discs (DVDs) appearing on the

market now would benefit further fromthe use of blue-light lasers in place ofred-light lasers. The data capacity of thenew DVD models, now about 4.7gigabytes (GB)), could be increased to15 GB with the use of blue lasers. Butbecause of the larger quantum energygap that must be bridged, blue light isharder to produce than red light in semi-conductor lasers. Last year Nichiadeveloped a pulsed blue diode laser,based on gallium-nitride materials, whichare thought to possess better commer-cial prospects than GaAs-based lasers.

Two Types of Superconductivityat the Same Time? Putting a direct cur-rent (dc) through a metallic sample,physicists can observe the onset of su-perconductivity as the resistance dropsto zero at the critical temperature. Inalternating-current (ac) studies, onelooks for peaks in a plot of the imped-ance (analogous to resistance) versustemperature. Performing ac microwavemeasurements of YBCO superconduc-tors, Srinivas Sridhar of NortheasternUniversity has observed two peaks, oneat a temperature just below 93 K (therecognized critical temperature) andanother at 65 K, which he interprets asa hint for the onset of a further kind ofelectron pairing. Signs of this secondtype of superconductivity may havebeen present in previous experiments,Sridhar said, but only now, with the

use of new high-purity crystal samples,is direct evidence available.

Single Magnetic Atoms. Singlemagnetic atoms have been found todisrupt superconductivity on an atomicscale, according to researchers at IBMAlmaden. As part of their microscopicstudy of magnetism, Ali Yazdani andhis IBM colleagues deposit single man-ganese (Mn) and gadolinium (Gd)atoms, each of which exerts magneticforces, onto a niobium metal, which isa superconductor at low temperatures.By measuring the tunneling current thatflows from the surface to the probe ofa scanning tunneling microscope, theresearchers detected the loss of super-conductivity in the vicinity of theisolated magnetic atoms. This repre-sents the first time a local loss of thesuperconducting state at the atomicscale has been detected. The research-ers theorize that the atoms break upnearby electron pairs which constitutesupercurrents.

Novel Scanning Probes. Whenelectrons trapped at the interface be-tween two semiconductors aresubjected to high magnetic fields andare held at low temperature, they canform into strange configurations, someof which appear to have fractionalcharges. Physicists naturally want tomap this “quantum Hall effect” with asmuch precision as possible. At a Mon-

Tax-free Accumulated Savings at Retirement Age[from investing $10,000 per year earning 8% net yearly return]

Investment Years 5 10 15 20 25

Outside Plan $34,607 $78,355 $133,661 $206,578 $291,964

Inside Plan $38,016 $93,873 $175,946 $296,539 $473,726

accumulated savings depending uponthe size of the account and your age atdeath. What to do? Naming a spouse asthe heir is a choice that makes tax senseas a special rule permits the survivingspouse to defer tax by rolling over theinherited distribution from the accountto an IRA.

But what happens to the estate if achild becomes the beneficiary? Ac-knowledging that the followingexample uses the maximum estate taxand income tax rates, it still clearly il-lustrates the point. Assume that thereis $1 million in the retirement accountwhich passes directly to a child. If theowner of the account is in the 55% fed-eral estate tax bracket, the federal estatetax consumes $550,000 of the account,leaving $450,000 to the beneficiary,before income taxes. Assuming that the$450,000 would be subject to a maxi-mum income tax rate of 39.6%, thisresults in federal income taxes of$178,200. This combination of federalestate and income taxes means that thebeneficiary will receive $271,800 ofwhat started out as $1 million. Thisexample does not include state incomeor state estate taxes. Because of thiscombination of taxes (which can alsoinclude a 15% excise tax on certainlarger retirement account balanceswhich can be the case for many APSmembers), qualified plan and retire-ment assets are particularly useful as

sources for potential charitable giving.If, in this example, the person had

named a charitable organization as thebeneficiary of the $1 million retirementaccount, neither estate taxes nor in-come taxes would have been incurred,and the cost to the family would havebeen only slightly over 27% of the valueof the account. However, perhaps youwant to use the retirement account toprovide an income interest for a childover his/her lifetime with the charitythen benefiting from the assets. If acharitable remainder trust is named asthe beneficiary of the retirement ac-count, a charitable deduction for estatetax purposes can be a benefit so thatless federal estate tax is paid. Furtherthe payment of the entire retirementaccount to the charitable remaindertrust will not result in immediate in-come taxation. The effect is that morefunds may be available in the chari-table remainder trust to be invested forthe benefit of the child during his orher lifetime which could actually pro-vide more income than if a bequest ofthe retirement account had been madedirectly to them. In addition, a worthycharity benefits from your generosity.

The bottom line is that, in savingfor retirement and receiving retirementplan distributions, it is very importantto do very careful planning to assure thatintended beneficiaries receive the fruitsof our labor…not the IRS. Handouts fromthe March meeting session and informa-tion on the speakers, as well as relatedarticles on this subject, are available toAPS members at no charge and may behelpful background if you decide to raisethis subject with your own financial advi-sor. Simply e-mail me at (logan@aps.org)with your name and address requestingthe “retirement planning packet”.

APS News June 1997

6

day morning session, Ray Ashoori ofMIT announced the development of ascanning probe which, sitting outsidethe semiconductor structure in whichthe 2-dimensional electron structuresare forming, can nevertheless renderimages of the structures with 40-nmspatial resolution. Answering somequestions, the images pose new chal-lenges, in the form of unexplainedlateral oscillations of the electronclumps. Ashoori’s probe may be use-ful in electronic chip design and testingsince it can measure the local densityof electrons even hundreds of ang-stroms inside a semiconductor.

New Liquid Crystal Phase Discov-ered With DNA. While many scientistsstudy DNA to unravel the mysteries oflife, others take advantage of the factthat DNA is an easily replicated andmanipulated version of a polymer—along, chainlike molecule—to discovernew intricacies in materials physics.Helmet Strey and his colleagues at theNational Institute of Health have pre-pared a dense array of DNA moleculesin solution to form a liquid crystal, astate of matter in which molecules arearranged to a degree of order that liesbetween that of crystals (highly or-dered) and liquids (less highlyordered). Using x rays to observe theirsamples, they have discovered a newconfiguration, or phase, of liquid crys-tal never before observed in anymaterial. Known as the line hexaticphase, it was originally predicted byJohn Toner of the University of Oregonin the 1980s. The researchers hope thatusing DNA will allow them to find andto investigate more types of liquid crys-talline arrangements.

Waste is a Terrible Thing to Mind.As the Cold War recedes into historyand as weapons containing radioactivewarheads are dismantled, a vast amountof chemical and fissionable materialmust be inventoried and disposed of.The cleanup at U.S. Department ofEnergy labs alone — 120 sites in 36states — will require many years andbillions of dollars. Speakers at a Tues-day afternoon session revealed theextent to which this tremendous so-cial/technical undertaking has turnedan important corner, just in the pastyear. For example, an emphasis onpaper studies and litigation has shiftedto actual cleanup activities at specificsites. Chaired by David L. Bodde of theUniversity of Missouri at Kansas City, thesession speakers included Alvin L. Alm,DOE Assistant Secretary for Environmen-tal Management; Frank L. Parker ofVanderbilt University; Thomas Winstonof the Ohio Environmental ProtectionAgency; and Charles Powers of the En-vironmental and Occupational HealthSciences Institute.

Separating Microscopic Particlesby Exploiting Brownian Motion. Ata Tuesday afternoon session, MartinBier of the University of Chicago de-scribed efforts to build a machine thatseparates different-sized colloids (tiny,slightly charged particles in fluids) byexposing them to fluctuating electricfields and taking advantage of theirBrownian motion, the random move-ments that they experience when theycollide with fluid molecules. Bier’s teamhas demonstrated that it is possible todesign a device for separating differ-ent-sized colloids because particles ofunlike sizes experience different lev-els of friction in a fluid and therebyundergo differing amounts of Brown-ian motion. One would be able to addparticles for separation continuously to

such a device, unlike centrifuges, whichmust be started and stopped every timenew particles are added.

10 Megagauss Fields. For a varietyof condensed matter experiments (suchas studies of the quantum Hall effect),physicists need strong magnetic fields.The highest steady fields attainable areabout 40 Tesla (T), or 40,000 gauss.Operating in a pulsed mode, magnetsat Los Alamos have reached 70 T, butonly for periods of 20 to 50 msec. Withnested pulsed magnets, fields in excessof 100 T will be reached in the nearfuture. By resorting to explosive com-pression of the magnetic flux in amagnet, even higher fields can beachieved. James Brooks of Florida StateUniversity reported on the attempt tocarry out condensed matter studies inextremely high magnetic fields, albeitfor a period of only a microsecond orso. By using 20 kg of explosives (theskills of weapons engineers came inhandy at this stage), a solenoid mag-net, made in Russia and consisting of amesh of thin copper wires was im-ploded, resulting in fields estimated tohave been as high as 1000 T, or 10megagauss.

SQUIDs for Nondestructive Evalu-ation of Aircraft. SuperconductingQuantum Interference Devices(SQUIDs), the most sensitive magneticfield sensors known to date, are nowof sufficient sensitivity and reliabilityto find practical use in biomagnetism,geomagnetism and nondestructiveevaluation of aircraft. The latter is thefocus of a recent German research col-laboration, led by Rohmann GmbH,which has been in the nondestructivetesting business for 20 years. Accord-ing to Hans-Joachim Krause (Instituteof Thin Film and Ion Technology,Juelich), SQUIDs are superior to con-ventional eddy current testing withcoils because their high sensitivity atlow frequencies allow for larger pen-etration depths.

Recently, aircraft wheel testing wassuccessfully demonstrated with a pro-totype SQUID system in the Lufthansamaintenance facility at Frankfurt’s air-port. One challenge is to operate theSQUID sensor integrated into ahandheld system during movement inthe strong ambient fields commonlyfound in aircraft maintenance facilities.Also, the SQUID must be equippedwith mobile cooling with a lightweightnitrogen cryostat. In the near future,an automated wheel testing unit willbe development. For fuselage testing,the SQUID will be integrated with anindustrial scanning system. The projectcontinues until the summer of 1998,after which Rohmann intends to intro-duce the new SQUID device into themarketplace.

Hydrogen and Deuterium in Sili-con Device Processing. Metal oxidesemiconductor (MOS) transistors arethe basic building blocks of silicon in-tegrated circuits. Their stability andlifetime depend on the degree of per-fection of the interface between thesemiconductor, silicon and the oxide.The high quality is achieved by intro-ducing hydrogen atoms into theprocess to passivate any defects, suchas dangling bonds. However, recentsurface science experiments using ascanning tunneling microscope haveshown that incorporating deuteriuminstead of hydrogen leads to significantimprovement in the lifetime of MOStransistors, because it is even harder todesorb from silicon surfaces. Inaddition to its impact on current gen-

Highlights from Kansas City (Continued from page 1)

erations of devices, the suppression ofdefects becomes even more essentialfor future devices, in which oxide thick-ness and devise dimensions will shrinkstill further and the effects of any re-maining defects will be magnified.

Advanced Memories and CMR. In-formation technology is a rapidlyevolving industry with a continuallychanging landscape, but one constantfactor is the ongoing need for moreinformation storage for a broad rangeof applications encompassing smallportable digital cameras to huge datawarehouses used by global companies.According to James Brug of Hewlett-Packard Laboratories, who spoke at aWednesday morning session, storinginformation magnetically has long beenthe dominant technology, but this be-comes more difficult as areal densitiesincrease. However, new understandingof the interaction of electrons with themagnetization in thin films andsuperlattices is enabling the possiblityof storage architectures other than ro-tating disks. Some alternatives beingconsidered include new magneto-trans-port effects, such as colossalmagnetoresistance and spin tunneling,which might be utilized in advancedmemory applications.

Nontechnical Sessions.

Entrepreneurial Physics. On Tues-day morning, the Forum on Industrialand Applied Physics held a session onentrepreneurial physics organized by RayO’Neal. W.K. Warburton of X-Ray Instru-mentation Associates, a small company thatdevelops specialized electronics to supportthe detectors used at synchrotron radia-tion facilities, reviewed the issues a smallcompany must deal with in order to sur-vive in the business world. His companyis currently extending its expertise tothe development of spectrometry in-struments for specialized medicalmarkets. Virgil Elings, president of Digi-tal Instruments, also reviewed thehistory and development of what isnow the world’s largest manufacturerof scanning probe microscopes, andoffered suggestions for entrepreneur-ial-minded physicists interested instarting a technology business.

Civic Science. Changing the in-creasingly negative perception ofscience by the general public and leg-islature was the focus of a Tuesdaymorning session on civic science.Speakers included Robert Greenler ofthe University of Wisconsin, Milwau-kee, founder of a highly popular seriesof science programs for the publiccalled “The Science Bag,” now in its24th year. Since its inception, the pro-gram has drawn a cumulative audienceof well over 100,000. In addition, CarlM. Bender described how the physicsdepartment of Washington Universityin St. Louis has established a physicsand society course as part of a con-tinuing effort to raise the level ofscience literacy among bright studentswho do not intend to take furthercourses in science or mathematics. Thecourse considers such issues as theavailability of energy, nuclear weapons,the greenhouse effect, the ozone hole,risk analysis, the scientific method, andclaims of the paranormal.

Centenary of the Electron.Wednesday afternoon’s program featureda special symposium commemorating thecentennial of the discovery of the electronin 1897. According to William Evenson ofBrigham Young University, who chairedthe session, the electron’s discovery cul-minated an era of cathode ray physics,

during which it was not clear whethercathode rays were particles of electric-ity or waves. Nor was it suspected thatthere might be particles of subatomicsize until J.J. Thomson’s classic experi-ments on the mass-to-charge ratio forcathode rays. The discovery of the elec-tron led not only into investigations ofthe subatomic world, but ultimately tonuclear physics and quantum physicsas well.

Furthermore, it was the particle thatshowed the existence of intrinsic spin,and also led the way in the develop-ment of our understanding of theproperties of large collections of sub-atomic particles. More recently, thestudy of systems of strongly interact-ing electrons has led to the discoveryof unexpected new phenomena, suchas high temperature superconductivity,intermediate valences, and the frac-tional quantum Hall effect. Althoughthese are not unique to electron sys-tems, their discovery in those systems“has changed the way we understandquantum mechanics and enriched ourunderstanding of how interactions canchange physical systems,” saidEvenson.

Additional highlights and session sum-maries from the Kansas City meetingare available for viewing or down load-ing in the online version of APS Newslocated under the APS News button onthe APS home page [www.aps.org].

Special thanks to Philip F. Schewe andBenjamin Stein of the American Insti-tute of Physics’ Public InformationOffice for contributing to the coverageof technical sessions in this issue.

1997 MARCH MEETINGPROGRAM COMMITTEE

Chair: David Lang, AT&T Bell LabsMembers: Robert Richardson,Cornell University (Sorters MeetingOrganizer); Denis Rousseau, AT&TBell Laboratories (Division of Biologi-cal Physics); James Langer, Universityof California,Santa Barbara (Divisionof Condensed Matter Physics); Rob-ert Silbey, MIT (Division of ChemicalPhysics); Marvin Kalos, Cornell Uni-versity (Division of ComputationalPhysics); James Riley, University ofWisconsin (Division of Fluid Dynam-ics); Ken Shull, NorthwesternUniversity (Division of High PolymerPhysics); G. Slade Cargill III, Colum-bia University (Division of MaterialsPhysics); Paul Houston, Cornell Uni-versity (Division of Laser Science);Robert Soulen, Jr., Naval ResearchLaboratory (Instrument and Measure-ment Science Topical Group); DavidJiles, Iowa State University (TopicalGroup on Magnetism); LalitChhabildas (Shock Compression ofCondensed Matter Topical Group);Katepalli Sreenivasan, Yale University(Statistical and Nonlinear PhysicsTopical Group); L. Craig Davis, FordResearch Laboratory (Forum on Indus-trial and Applied Physics); JohnAhearne, Sigma Xi (Forum on Physicsand Society); Rush Holt (Forum onEducation); John Rigden, AmericanInstitute of Physics (Forum on Historyof Physics); Roberto Merlin, Universityof Michigan (Forum on InternationalPhysics); Laurie McNeil, University ofNorth Carolina (Committee on Statusof Women in Physics); Robert Perry,Ohio State University (Committee onMinorities).

June 1997 APS News

7

DCMP and DMP Celebrate 50 Years

The APS Division of CondensedMatter Physics (DCMP) and the

Division of Material Physics (DMP)celebrated their 50th anniversary at the1997 March APS meeting in Kansas City,Missouri. Almost 50 past and presentofficers of these divisions, as well asspecial APS guests, participated in adinner and reminiscent discussionsSunday evening prior to the beginningof the scientific sessions.

Originally called the Division ofSolid State Physics (DSSP), the unit wasformed in 1947, the third society divi-sion. (The Division of Atomic, Molecular,and Optical Physics was established in1943, and the Division of High PolymerPhysics was formed in 1944.) In 1978the DSSP was renamed the Division ofCondensed Matter Physics to recognizethat disciplines covered in the divisionincluded liquids (quantum fluids) aswell as solids. Today the DCMP is thelargest of all APS divisions.

In 1984, the Topical Group on Ma-terials Physics was formed from asubset of DCMP scientists. This topicalgroup grew to become the Division ofMaterials Physics (DMP) in 1990. TheDMP, which is just seven years old, isthe fifth largest division today.

The chairpersons of the two divi-sions, David Lang (DCMP) and SladeCargill III (DMP), were the official hostsof the celebration. The evening beganwith cocktails and hors d’oeuvres fol-lowed by a dinner at the Kansas CityMarriott downtown hotel. A highlight ofthe after dinner discussions was a con-ference call with two of the originalfounders of the DSSP, members of theso-called “group of six”: Sidney Siegeland Fred Seitz. These individuals spent

over half an hour telling about the earlydays of solid state physics and the for-mation of the division.

Although solid state physics was arecognized scientific topic in the 1940’s,the society was dominated by researchon nuclear physics. Dramatic break-throughs in solid state physics were onlybeginning to happen.(The transistor wasdiscovered the same year as the DSSPwas formed.) The group of six convincedthe APS that a division which specifi-cally focused on solid state physicswould highlight the importance of thisemerging discipline and better serve theneeds of this still small, but growing,community. They never suspected thatcondensed matter would grow to be-come almost half of all physics activity

Neil Ashcroft, DCMP chairperson forthe 1987 March APS meeting in NewYork City, spoke of the events leadingto the “Woodstock of Physics” meet-ing, following the discovery of hightemperature superconductivity. Thismeeting clearly fell outside the normalguidelines, with events unfolding longafter the final organization and ses-sion planning meeting which tookplace the previous Fall. Other discus-sions related some of the conflictsbetween groups of scientists which ledto the formation of the DMP in the1980s. Fortunately, these conflicts arehistorical events which are not presenttoday and both the DCMP and the DMPare now working amicably together topromote science in their largely over-lapping areas of interest.

The 50 celebration was reported on byDonald Gubser, Sectretary-Treasurer ofDCMP.

The APS joined the Federation ofMaterials Societies (FMS) in 1995.

The FMS is an umbrella organizationof societies and affiliates which areinvolved with materials science,engineering, and technology. Itspurpose is to aid the materialscommunity to obtain and exchanginformation with policies makers.

The APS is officially represented inthe FMS by the Divisions of CondensedMatter Physics and Materials Physics.Donald Gubser, Naval Research Labora-tory, is an APS liaison to the FMS as wellas Sectretary-Treasurer of the Divisionof Condensed Matter Physics. He re-ported on APS environmental activitiesat the last FMS workshop such as APS

statements on enviornmental issues(which can be found on the APS homepage under the Public Affairs and POPAbuttons) and meeting symposia. An ex-ample of the latter was the Waste is aTerrible Thing to Mind session at theMarch Meeting (see page 6)

According to Gubser, the strengthof materials research and engineeringlies in their interdisciplinarity and inthe fact that there is a continuity of ac-tivities from fundamental sciencethrough engineering, applications, pro-cesses and commercial products. Theresult, however, is that segments of thematerials community often find it diffi-cult to discuss common problems,priorities and policies.

APS Role in the Federation of Materials Societies

Nominations for 1998 APSPrizes and Awards

The following prizes and awards will be bestowed at meetings of the Society in thecoming year. Members are invited to nominate candidates to the respective committeescharged with the privilege of recommending the winners. A brief description of eachprize and award is given below, along with the addresses of the selection committeechairs to whom nominations should be sent. Please refer to the APS Membership Direc-tory, pages xxiii- xxxix, or the APS home page [http://aps.org] under the Prize and Awardbutton, for complete information regarding rules and eligibility requirements for indi-vidual prizes and awards.

1998 FLUID DYNAMICS PRIZE

Sponsored by the AIP Journal, Physicsof Fluids.Purpose: To recognize and encourage

outstanding achievement in fluid dy-namics research.

Nature: The prize consists of $5,000, acertificate citing the contributionsmade by the recipient, and a travelallowance to the meeting at whichthe prize is bestowed.

Send name of proposed candidate andsupporting information before 2 Sep-tember 1997 to: James Martin Wallace,Dept of Mechanical Engr, Univ ofMaryland, College Park, MD 20742,phone: (301) 405-5271, fax: (301) 314-9477, email: wallace@eng.umd.edu.

1998 OTTO LAPORTE AWARD

Sponsored by the friends of OttoLaPorte and the APS Division of FluidDynamics.Purpose: To recognize outstanding re-

search accomplishments pertaining tothe physics of fluids.

Nature: The award consists of $2,000and a certificate citing the contribu-

tions made by the recipient.Send name of proposed candidate and

supporting information before 2 Sep-tember 1997 to: Frederick K. Browand,Dept of Aerospace Engr, USC, Los An-geles, CA 90089-1191, phone: (213)740-5359, fax: (213) 740-7774.

1998 THE DAVISSON-GERMERPRIZE

Correction from previousannouncements

Sponsored by Lucent Technology.Purpose: To recognize and encourage

outstanding work in atomic physicsor surface physics. The prize for 1998will be awarded for work in thearea of atomic physics.

Nature: The Prize consists of $5,000and a certificate citing the contribu-tions made by the recipient orrecipients.

Send the name of candidates, biographi-cal information and supporting lettersbefore 1 July, 1997 to: Andrew C Tam(Chair), 21463 Continental Cir , SaratogaCA 95070, phone (408) 927-1943, emailACTAM@almaden.ibm.com.

The FMS, founded more than 20years ago, represents 17 member pro-fessional societies and three affiliateand two liaison members. These orga-nizations, in turn, have more than700,000 members. The FMS has been aleader in crystallizing policies in sub-jects ranging from: materials andresource conservation, materials pro-cessing and synthesis, materials andnational competitiveness, and delinea-tion of unique features of materialsscience and engineering.

The FMS sponsors periodic work-shops, a biennial meeting on mattersof materials policy, and issues reports,white papers, and recommendations foractions. Recently completed reports in-clude “Impact of the new Congress onMaterials Policy” (March 1995), “Tech-nology Policy Recommendations fromthe FMS” (January 1995), and “Materi-als Agenda for the 21st Century:

Policies, Priorities, Payoffs” (June 1996).Most recently FMS held a workshop

to document the current activities un-derway in FMS member societies andto provide an insight into innovativeapproaches to the environmental im-provement field.

The FMS does several other thingsfor the materials community. FMS mem-bers participated in a “Science andTechnology Congressional Visits Day”where meetings with decision makersin congress and their staff took place.Similarly, the FMS joined with 45 otherscientific societies (including the APS)in calling on the Federal governmentto reverse the decline in U.S. invest-ment in science.

For more information on the FMS,contact Betsy Houston atbetsyhou@ix.netcom.com or DonaldGubser at gubser@anvil.nrl.navy.mil.

Prize NominationDeadlineDavid Adler Lectureship Award 07/01/97

Will Allis Prize 07/01/97

Apker Award 07/01/97

Hans A. Bethe Prize 07/01/97

Dissertation in Beam Physics 07/01/97

DAMOP Dissertation Award 11/18/97

Biological Physics Prize 07/01/97

Tom W. Bonner Prize 07/01/97

Edward A. Bouchet Award 07/01/97

Oliver E. Buckley Prize 07/01/97

Davisson-Germer Prize 07/01/97

John H. Dillon Medal 07/01/97

Fluid Dynamics Prize 09/02/97

Joseph A. Burton Forum Award 07/01/97

Dannie Heineman Prize 07/01/97

High Polymer Prize 07/01/97

Frank Isakson Prize 07/01/97

Joseph F. Keithley Award 07/01/97

Otto Laporte Award 09/02/97

Lilienfeld Prize 07/01/97

Maria Goeppert-Mayer Award 05/30/97

Dissert. in Nuclear Physics Award 07/01/97

Onsager Prize 07/01/97

George E. Pake Prize 07/01/97

W. K. H. Panofsky Prize 07/01/97

Aneesur Rahman Prize 07/01/97

Prize for Research in an

Undergraduate Institute 07/01/97

Earl K. Plyler Prize 07/01/97

J. J. Sakurai 07/01/97

Arthur Schawlow Prize 07/01/97

Leo Szilard Award 07/01/97

Robert R. Wilson Prize 07/01/97

1998 APS Prize and Award Nomination Deadlines

The following are impending deadlines of APS Prizes and Awards. For complete infor-mation regarding the description of each prize, previous recipients and the chair of prizeselection committees, please see the Prize, Awards and Fellowship Page of the APShome page [http://www.aps.org]; consult the front of the APS Membership Directory,email your request to honors@aps.org, or call (301) 209-3268.

APS News Online latest edition• Physics News in 1996 (May)• Campaign for Physics Update (June)Public Affairs• Speech by Dr. Mary Good• Current Energy SituationMeetings• PC’97 [DCOMP & FIAP Meeting]

•Conference of Physics DepartmentChairs

Career/Employment• Summer Physics Jobs• NRC Summer Internship Program• Career & Professional Development

Task Force Report

CAUGHT IN THE WEB

Notable additions to the APS Web Server. The

APS Web Server can be found at http://www.aps.org

The winner of the March Meeting drawing for PhysicalReview, The First Hundred Years is:Donald Waldo, student member

APS News June 1997

8

THE BACK PAGE

The Back Page is intended as a forum to foster discussion on topics of interest to the scientific community. Opinions expressed are not necessarily those of the APS, its elected officers, or staff. APS News welcomesand encourages letters and submissions from its members responding to these and other issues.

President Clinton has talked a lotabout building a bridge to the 21st

Century and, our philosophical differ-ences aside, I want to help him buildthat bridge…with Bucky Balls.

“Bucky Ball” is the nickname forBuckminsterfullerene, a molecular formof carbon that was discovered by Pro-fessors Robert F. Curl and Richard E.Smalley of Rice University in Houston.They won the 1996 Nobel Prize inChemistry for this discovery.

Bucky Balls were named after R.Buckminster Fuller, the architect famousfor his geodesic domes, because thisnew molecule closely resembles hisdesigns. The silly nickname notwith-standing, their discovery was abreakthrough that will have scientificand practical applications across a widevariety of fields, from electrical conduc-tion to the delivery of medicine intothe human body.

Bucky Balls are impervious to radia-tion and chemical destruction, and canbe joined to form tubes 10,000 timessmaller than a human hair, yet 100 timesstronger than steel. Use of the moleculesis expected to establish a whole newclass of materials for the constructionof many products, from airplane wingsand automobile bodies to clothing andpackaging material.

This is old news to those of you in-volved in molecular physics, but thinkabout it this way: Because we encour-age the kind of thinking that leads todiscoveries like Bucky Balls, the UnitedStates stands as the economic, military,and intellectual leader of the world. Weachieved this not by accident, but by acommon, unswerving conviction thatAmerica’s future was something to planfor, invest in and celebrate. Using theproducts of imagination and hard work,from Winchester rifles and steam en-gines to space shuttles, Americans builta nation. We’re still building, but forwhat we need in the next century, we’regoing have to turn to people like Curland Smalley and you to give us materi-als like Bucky Balls, and thegovernment has a role to play.

Unfortunately, over the past 30 years,American government has set differentpriorities. In 1965, 5.7 percent of thefederal budget was spent on non-de-fense research and development.Thirty-two years later in 1997, that fig-ure has dropped by two-thirds. Wespend a lot more money than we didin 1965, but we spend it on social pro-grams, not science. We invest in thenext elections, not the next generation.

The United States is under-investingin basic research. That’s right. The au-thor of the landmark deficit reductionlegislation known today as Gramm-Rudman supports the idea of thegovernment spending more money onsomething.

Not only do I support the idea ofspending more on science and technol-ogy, I have introduced two pieces oflegislation which would help achievethat goal. The first bill is the National

Research Investment Act, which woulddouble the amount spent by the fed-eral government on basic research inscience and medicine over 10 yearsfrom $32.5 billion in 1997 to $65 bil-lion in 2007. The second, the NationalResearch and Development Act, wouldpermanently extend the research anddevelopment tax credit.

If we as a country do not restore thehigh priority once afforded science andtechnology in the federal budget andincrease federal investment in research,it will be impossible to maintain theUnited States’ position as the techno-logical leader of the world. Since 1970,Japan and Germany have spent a largershare of their national income on re-search and development than we have.We can no longer afford to fall behind.Expanding the nation’s commitment toresearch in basic science and medicineis a critically important investment inthe future of our nation. It means say-ing no to many programs with strongpolitical support, but by expanding re-search we are saying yes to jobs andprosperity in the future.

The R&D tax credit was originallyenacted as a part of President Reagan’sEconomic Recovery and Tax Act of 1981in order to encourage greater privatesector investment in research and de-velopment, and its benefits have beenenormous. Studies show that each dol-lar of the credit yields up to two dollarsin additional private R&D spending.Furthermore, the rate of return fromR&D spending to society as a whole isestimated to be as high as 60 percent.Since its creation in 1981, the credit hasbeen extended seven times, and it iscurrently set to expire on May 31, 1997.

Given that the ratio of R&D spend-ing to output rose 40% in the 1980swhen the R&D credit was in effect forthe longest period of time, it is not un-reasonable to expect that the benefitsof the credit will only be enhanced if itis extended permanently. A permanentextension of the R&D credit would en-courage companies to take onadditional research and developmentprojects by guaranteeing that the creditwill be in effect during these long-terminitiatives. In Texas alone, the averagehigh-tech job pays $47,019 a year —almost $20,000 more per year than theaverage private sector salary of $27,147.

The need to make the credit perma-nent is only further highlighted by thefact that in 1996, for the first time in itshistory, the R&D credit was allowed tolapse between July 1, 1995 and July 1,1996. Haphazard and unpredictabletemporary extensions of the credit, com-bined with this recent lapse, haveunderstandably left the research com-munity in a state of confusion anduncertainty. Do any of us doubt thatnew home sales would drop if prospec-tive buyers thought the mortgageinterest deduction might disappear 5years into their 20 year mortgage?

Businesses cannot and do not ignorethe possibility of future gaps in the R&D

credit, and will be forced to scale backnew long-term projects if they cannotbe certain that the credit will continue.We should permanently extend the R&Dtax credit to permanently remove thisunnecessary barrier to long-term re-search and development which hasbeen created by the stop-and-go exten-sion process.

I should also point out that the R&Dcredit has a long history of bipartisansupport. The president has signaled hissupport for the credit, not only by sign-ing last year’s extension as a part of theSmall Business Job Protection Act, butalso by proposing a further extensionas a part of his 1998 Budget. Unfortu-nately, his proposal follows theill-advised precedent of merely tempo-rarily extending the credit.

I believe that if we want the 21st cen-tury to be a place worth building a bridgeto, and if we want to maintain the UnitedStates’ position as the leader of the freeworld, then we need to restore theprominence that basic research once hadin the federal budget. Our parents’ gen-eration fought two world wars, overcamesome of the worst economic conditionsin the history our nation, and yet stillmanaged to invest in America’s future.We have an obligation to do at least anequal amount for our children andgrandchildren.

Over the past 30 years, we have notlived up to this obligation, but it isn’ttoo late to change our minds. The dis-covery of Bucky Balls is a testament tothe resilience of the American scien-tific community. I believe that if weonce again give scientists and research-ers the support that they deserve, if wemake the same commitment to ourchildren’s future that our parents madeto ours, then the 21st century promisesto be one of unlimited potential.

For those of you who want to help,you should contact your Senators andurge them to cosponsor these impor-tant bills. The National ResearchInvestment Act is S. 124, and the Na-tional Research and Development Actis S. 355. In the weeks since I intro-duced S. 124, I have received dozensof letters of support from universitiesand organizations (including, of course,the American Physical Society), repre-senting hundreds of thousands ofscientists and researchers from acrossthe country. Let your elected officialsknow you believe it is vital we reversethe disturbing trend toward shortchang-ing critical investments in research.

America is a great and powerfulcountry for two reasons. First, we havehad more freedom and opportunity thanany other people who have ever livedand with that freedom and opportunitypeople like us have been able to achieveextraordinary things. Secondly, we haveinvested more in science than any peoplein history. Science has given us the toolsand freedom has allowed us to put themto work. If we preserve freedom and in-vest in science, there is no limit on thefuture of the American people.

Scientists will Build the Bridge to the 21st CenturyBy Phil Gramm, United States Senator

If we as a country donot restore the highpriority once affordedscience and technologyin the federal budgetand increase federalinvestment in research,it will be impossible tomaintain the UnitedStates’ position as thetechnological leader ofthe world.

In 1965, 5.7 percentof the federal budgetwas spent on non-defense research anddevelopment.Thirty-two years later in1997, that figure hasdropped by two-thirds.

June 1997 APS News

9

U-M Scientists Put the Squeeze on AtomsUsing ultra-fast pulses of laser light, University of Michigan physicists have

found a way to control the random oscillations of atoms in a crystal lattice:making their study the first experimental modification of one of the most funda-mental quantum states of solid matter. Approximately 10 years ago, scientistsdiscovered how to create a “squeezed state” for quantum particles of light en-ergy (photons). However, until the U-M experiment, no one had been able to dothe same with phonons, which carry vibrational energy through a solid.

“We can calculate probabilities for an atom’s location within a specific area ofuncertainty, but we can never know precisely where the atom will be,” saidRoberto Merlin, U-M professor of physics. “It’s like hide-and-seek. With short-pulse, high-power lasers, we can reduce the size of the volume where the atomcan hide.” He likens the atomic structure of a solid at the quantum level to acloud whose area is defined by the atom’s random motion within the solid,where points of higher density in the cloud represent points where the probabil-ity of finding the atom is higher.

The experiment was conducted using a titanium-sapphire laser system at theU-M Center for Ultrafast Optical Science, firing 70-femtosecond laser pulses fo-cused on a tiny spot on a potassium tantalate crystal. The laser beam was thensplut into two parts, and one beam is diverted along an alternate path, so thesecondary pulse arrived at the target a few picoseconds after the initial pumppulse. The stronger pump pulse hits the atoms in the crystal lattice like a ham-mer, producing a force which creates pairs of phonons and makes the atomiclattice oscillate. The weaker probe pulse is scattered by these phonos as it passesthrough the lattice later in time, and researchers then measured the amount ofprobe pulse energy that makes it through the crystal to determine the behaviorof the atoms inside.

“Our goal was to learn how to control matter — to tell the atoms what to do,rather than just watch them do something,” said Merlin. While he cautions that itis too early to speculate on potential applications for the squeezed state in mat-ter, the U-M team is planning future experiments to replicate the squeezed statein other types of crystal.

ResearchersDevelop World’sFirst Type IIQuantum CascadeLaser

A team of researchers from the Uni-versity of Houston Space VacuumEpitaxy Center (SVEC) and Sandia Na-tional Laboratories has developed theworld’s first type-II quantum cascade(QC) laser. The laser has the potentialto operate at a higher temperature anddeliver more power at the 3 to 12 mi-cron wavelength than previous diodelaser technology.

The type-II QC laser combines theadvantages of a cascade design and theinterband transitions of the conven-tional diode laser. It is based on thetype-II heterostructure, in which theconduction-band edge of one layer canbe lower in energy than the valence-band edge of the adjacent layer.According to Shin-Shem Steven Pei, as-sociate director for research at SVEC,this unique energy-band alignment al-lows a staircase arrangement of thelaser’s active regions, such that everytime a carrier jumps down an energystep in the staircase as it crosses anactive region, a photon is emitted.

The new QC laser emits mid-infra-red light around 4 microns attemperatures up to -150 degrees Fahr-enheit, under 100-nanosecond currentpulses at a repetition rate of 1,000 persecond. Room temperature operationof a 4.2-micron light-emitting diode(LED) has also been demonstrated,with a 50% duty cycle and a repetitionrate of 1,000 per second. The averageoutput power is 140 microwatts — over1,000 times more than that of the firsttype-II QC LED reported by the samegroup in 1996 — and is much brighterthan the commercially available LEDsat the same wavelength. In another ef-fort, the SVEC team has alsodemonstrated an 8-micron LED in col-

laboration with H.C. Liu of the NationalResearch Council in Ottawa.

“Even though the current operatingtemperature and output power are notas high as other mid-infrared lasersdeveloped recently at SVEC and inother laboratories, the type-II QC de-sign offers clear advantges over theseother lasers and may significantly ad-vance the performance of thesedevices,” said Chih-Hsiang ThompsonLin, one of the team members. TheSVEC researchers have already devel-oped type-II quantum well lasers thatoeprate from 2.7 to 4.5 microns at tem-peratures up to 170 degrees Fahrenheit.A peak output of 0.27 watts at 3.2 mi-crons has been achieved when thedevice is pumped with optical pulsesat room temperature.

Mid-infrared optical systems operat-ing at 3 to 5 and 8 to 12 microns —two optical transmission windows inthe atmosphere — are in great demandfor a number of military, space andcommercial applications, including in-frared counter measures, covertillumination for night vision, free-spacecommunication, collision avoidanceand many medical procedues. The la-ser can also monitor many industrial,pollution, greenhouse, hazardous andtoxic gases. In fact, the availability oflow-cost light sources at mid-infraredwavelengths may revolutionize remotechemical-sensing technology for pol-lution monitoring, engine combustionand emission diagnostics, industrialprocess control, and the detection ofexplosives and illegal drugs.

Demonstration of the first type-II QClaser is the culmination of recent break-throughs in narrow bandgapsemiconductor material growth anddevice physics, and is an importantmilestone in the development of mid-infrared lasers. However, “This is onlythe first step toward the developmentof a viable technology for practical ap-plications,” said Pei, adding that SVECis committed to commecializing thetechnology for both space and terres-trial use.

Buckytubes, nanometer-wide tubesof carbon atoms, are stronger than steeland are now considered to constitutea fourth state of crystalline carbon. Thefirst three known forms of crystallinecarbon are graphite, diamond, and sol-ids of C-60 molecules, popularly knownas buckyballs. The many sessions de-voted to nanotubes at the 1997 APSMarch Meeting in Kansas City testify tothe rapid increase in interest in this re-search.

Nanotubes, stiffer than steel, only ananometer wide but many micronslong, are essentially rolled-up sheetsof carbon hexagons that exist in threevarieties: multishell tubes consisting ofseveral nested concentric cynlinders;isolated single-wall tubes; and orga-nized bundles or “ropes” of hundredsof single-wall nanotubes arranged in atwo-dimensional triangular lattice.Nanotubes are electrically versatile;doping can make them into metals, in-sulators, or semiconductors. They haveserved as the contacts in probe micro-scopes and have been used as fieldemitters and single-electron transistors.

According to John Fischer of theUniversity of Pennsylvania, nanotubeswere first observed as a minoritybyproduct from the carbon arc processthat yields fullerenes. Then scientistsdiscovered that large amounts ofnanotubes were formed in the mate-rial deposited on one of the electrodes,while the fullerenes were primarily inthe soot which filled the chamber.Single-wall tubes are formed if thegraphite target is doped with smallamounts of transition metals, whichcatalyze the growth of single-wall tubesat the expense of fullerene formation.Multi-wall tubes exist in a large rangeof diameters and concentric shells,making it difficult to determine the in-trinsic bulk properties. However,numerous experiments have been per-formed on isolated multiwall tubes todetermine electrical resistance andmechanical behavior, for example.

Richard Smalley of Rice University,winner of the 1996 Nobel Prize inchemistry for his discovery ofbuckyballs in 1985, reported that hislab currently produces nanotubes at arate of grams per day, but that within 5to 10 years this could be increased ona commercial basis to tons per day day.Smalley showed pictures of nanotubesthat swallow their own tails, formingclosed Bucky toruses, and diagrams ofbundles of nanotubes in which onetube stuck out further than its neigh-bors. Nested stages of such bundles,he said, could be used to fashion point-ers — macroscopic at one end buttapering down to a single carbon cellat the other end — with which onecould “write” patterns of molecules ona substrate, like an artist dipping apaintbrush into a palette of colors.

Electrically, these versatilenanotubes can be insulators, semicon-ductors, or conductors, depending ontheir symmetry, and are expected toexhibit magnetoresistance qualities. “Ifone could make a perfect joint betweendifferent classes of tubes, one wouldhave the world’s smallest diode, oneof the basic building blocks of elec-tronic devices,” said Fischer. In fact,arrays of the pointy nanotubes havealready been used as field emitters inflat panel displays. Attaching a semi-

conducting nanotube to a metallicnanotube one gets a nano-diode. If,furthermore, the joint is angled, thecomposite tube can actually conductbetter in a bent state than straight up;this property makes the structure intoa possible nanoswitch or strain gauge.

Fischer reported that nanotubeshave excellent mechanical strengthalong the direction of the tube axis,since the carbon-carbon bond is oneof the strongest known. Hence,bundles of long nanotubes embeddedin a matrix could be developed as high-strength, light weight, electrically con-ducting composite materials forstructural applications. In addition, theirlength is much greater than the diamter,making them valuable as flexible probetips in scanning probe microscopy,since they can explore very deep holes,a useful property for process controlin the fabrication of integrated circuits.Finally, nanotubes are hollow insideand in some cases liquids flow into thetubes by capillary action. “One couldimagine using nanotubes as tinyhypoderic needles, to deliver chemi-cals to a single cell,” said Fischer.

Steven Louie of Lawrence BerkeleyLaboratory studies nanotubes madeof boron and nitrogen, or of carbonmixed with boron and nitrogen,which have more consis tentsemiconducting behavior and hencehave greater potential nanodeviceapplications. In one configuration, ar ibbon of conduct ing carbonhexagons forms a corkscrew patternup the length of the tube. The currentflow through such a tube is thereforehelical; in effect this nanotube is theworld’s smallest solenoid magnet.

Louie’s LBL colleague, Alex Zettl, hasdeveloped a new random-marexnanotube electron field emission sourceusing arrays of carbon nantubes, whichhas demonstrated superior field emissioncharacteristics, simplicity and versatility.According to Zettl, the fabricationmethod could be easily scaled up, andtwo methods have been found that al-low reliable pixelation of the emissionsurface for display applications.

The Berkeley group is also pursu-ing the idea of using a randomdistribution of carbon nanotubes asan electronic computing machine.“Although in principle, one can makemany device e lements out ofnanotubes, in practice it is not yetpossible to syntheize them in a con-trolled way,” said Louie. However, an“as-growth” sample of entangledtubes will contain extremely highdensity of randomly arranged deviceelements, possibly orders of magni-tude higher than the present state ofthe art silicon technology. Louie’sidea is to attach leads to the sample,and develop algorithms to make useof the functions that already exist inthe sample. Such a device is expectedto have exception speed and ther-mal dissipation characteristics.

Cees Dekker of Delft University isable to study the electron transportproperties of single nanotubes by drap-ing them across a pair of electrodes;the current-versus-voltage plot is a se-ries of steps, indicative of a “quantumwire.” In general one would expect thisbehavior when the movement of elec-trons through a conductor is restrictedto one dimension.

Researchers Explore Applicationsfor Carbon Nanotubes

APS News June 1997

10

Scientists Use AFM to Explore DNAMechanisms

While many people view DNA as a purely chemical creature, defined by thesequence of its base pairs, scientists are now discovering how DNA acts as amechanical object which performs important functions in the body. Importantprocesses in single DNA molecules have been observed for the first time byusing the atomic force microscope (AFM), in which the deflections of a tinystylus over the contours of a surface can be turned into molecular-scale images.The ability to measure these forces with AFM and other techniques is allowingscientists to understand the physical basis of biochemical mechanisms respon-sible for life.

Using an AFM, Gil Lee of the Naval Research Laboratory found that a force ofabout 600 piconewtons was required to tear apart two complementary strandsof DNA, namely a 20-base-pair-long strand of polycytosine (a form of single-strand DNA) from single strands of polyinosine averaging 160 base-pairs long.The AFM can image surfaces both in air and under liquids at nanometer resolu-tion. NRL is using this techology to develop ultra-sensitive diagnostics tounderstand the molecular mechanicsms responsible for biofouling, and to mea-sure the forces necessary for DNA replication.

Living organisms are composed of cells built from macromolecules such asDNA and proteins. According to Lee, these macromolecules make up both thescaffolding that holds the cells together and the motos responsible for motion.Macromolecular function and structure are controlled by the forces betweenindividual units that make up macromolecules and their environment. “Previ-ously, our knowledge of these forces has been gathered from indirect x-raycrystallography and nuclear magnetic resonance measurements,” said Lee.

This new ablity to measure inter- and intramolecular forces in macromol-ecules such as DNA could offer unique insight into how structure producesfunction in these molecules. For example, the forces responsible for biologicaladhesion can now be directly studied at the molecular scale. Molecular adhe-sion controls a diverse array of phenomena such as cell migration in cancer andthe adhesion of barnacles to ship surfaces.

Pulling apart a DNA molecule at forces of 60 piconewtons, a University ofOregon-Santa Barbara team has found that DNA undergoes a change in struc-ture in which it exists at 1.7 times its original size. Such studies are important forunderstanding the process of DNA recombination—for example, when DNAmolecules from two parents combine to make the DNA for their child—becauseproteins that attach to DNA during this process stretch it to 1.5 times its originalsize.

The technology has also enabled scientists to observe transcription — thefirst step in a process which converts the genetic information contained in thecell’s DNA into proteins — for the first time. Carlos Bustamante of the Universityof Oregon and his colleagues presented movies showing the first stages of DNAreplication, in which a protein is seen to slide on DNA like a bead on a string tofind the exact site where it could attach and start the replication process. Bind-ing DNA and RNA polymerase (the protein that mediates the transcription ofDNA into RNA) to a mica surface, Neil Thomson of UC-Santa Barbara and hiscolleagues produced 5-nm-resolution movies of the transcription process, inwhich RNA polymerase pins down the middle of a single DNA strand and thenpulls the strand through as it starts transcribing the DNA into RNA using RNA-building-blocks called NTPs.

In what is believed to be the small-est focused point of light at anywavelength, SUNY-Stony Brook re-searchers have produced an x-ray beamthat is just 50 nanometers in diameter. Using this beam, the researchers havemapped the distribution of DNA in bullsperm and are aiming to usher in thefield known as ”nanotomography,” inwhich 3-D images would be producedof minuscule objects such as cells andsubcellular structures like nuclei andchromosomes.

Making such small useful beams re-quires a combination of very brightx-ray sources and high-quality x-rayoptics, such as mirrors, lenses, and pin-holes, which can now be fabricatedusing lithographic patterning tech-niques developed by thesemiconductor industry. And with theadvent of state-of-the artsynchrotron centers, such as the newAdvanced Photon Source atArgonne, researchers can now produceextremely intense versions of x-ray beams only millionths of a meterin diameter. These new sources haveenabled the creation of a new tool formaterial characterization on micron andsub-micron length scales, called an x-ray microprobe (XMP).

According to Eric Isaacs of LucentTechnologies, the XMP combines x-ray

sensitivity to crystallographic strain andtrace element distributions, with theirability to nondestructively probe deepinto a sample, and is beginning to havean impact on a broad range of disci-plines, including deviceengineering, materials science, biology,and environmental science. Withthese beams, Lucent researchers are nowable to perform quality-control studiesof the ultrathin quantum wells in state-of-the-art telecommunications lasers.

“In our highly technological society,particularly in communications in biol-ogy, complex electronic circuits,solid state lasers, and naturally occur-ring membranes and other cellularmaterials are lithographicallypatterened, or naturally patterend, onlength scales of one millionth of a meterand smaller,” said Isaacs. “Imagingthese patterned structures requiressmall x-ray beams.” The ultimate spa-tial resolution of a probe is fixed by itswavelength, which is why opticalprobes using visible light can observefeatures as small as a fraction of a mil-lionth of a meter.

X-rays can make much smaller mea-surements, comparable to the spacesbetween atoms in solid, because theirwavelength is 10,000 times smaller thanthat of visible light. In addition, x-raysare very penetrating and can be used

Certain metal hydrides, such as yt-trium-dihydride and hydrides of rareearth films, are shiny and make excel-lent mirrors. Adding just a bit morehydrogen, however, makes the mate-rial into a transparent window. SinceRonald Griessen of Vrije University inAmsterdam first announced this con-version process last year, muchprogress has been made in terms ofimproving the process and applying itto solid state devices. First, the switch-ing time (the mirror-to-windowconversion can go either way) has de-creased from tens of seconds to 40msec. Second, the contrast between theoptically “closed” and “open” states, asmeasured by the relative amount oflight transmitted, is now up to a factorof 1000.

The unexpected discovery of these“switchable mirrors” began in 1990, af-ter the announcement ofhigh-temperature superconductivity,when Griessen’s team decided tosearch for other potential high-tempera-ture superconductors, choosing tofocus on metallic hydrogen. However,instead of making hydrogen metallicunder very high pressures, they choseto first dissolve hydrogen in a metal tobreak the molecular bond, then com-press the sample under moderatelyhigh pressures to increase its metalliccharacter. They chose yttrium as a start-ing material.

At the end of 1994, a PhD studentin Griessen’s group observed that thinfilms of yttrium and lanthanum coatedwith palladium change from a shinymirror to a yellow transparent windowwhen absorbing hydrogen, a spectacu-lar and reversible change in opticalproperties. The transition is simply in-duced at room temperature bychanging the surrounding hydrogengas pressure or electrolytic cell poten-tial. “These films are unique in thesense that they can continuously, re-versibly and rapidly be switchedbetween a low resistivity metallic stateand a large gap semiconducting state,”said Griessen. Furthermore, the fact thatthe rare earth hydrides can make theswitch at room temperature is criticalto developing practical applications.

A theoretical explanation of this dra-matic optical switching phenomenon,lacking until now, has been advancedby Fu-Chun Zhang of the University ofCincinnati. The key, he says, appearsto be the behavior of the tiny hydro-gen atoms inside a lattice of much largeratoms. “We find it is the combinationof the ease of the hydrogen motion inthe metal and the dramatic change it

induces in electronic states that altersthe optical properties so quickly in hy-drides,” he said. Hydrogen can easilydiffuse in and out of a rare earth metallattice with only a small change in thecrystal structure. However, once itmoves in, a hydrogen atom binds anextra electron to form a negative ion,reducing the number of highly mobileconductive electrons.

According to Zhang, as the numberof hydrogen atoms increases in themetal, the material changes from adihydride to a trihydride, at whichpoint the mobile electrons becomestringly bound to hydrogen atoms toform highly localized states, such thatno electron can move through the lat-tice. This leads to a transition of theoptical properties from a highly reflect-ing mirror to those of a transparentwindow. “Instead of bouncing off thescattered, mobile electrons, light eas-ily passes through the material,” hesaid. Central to Zhang’s theory is thestrong correlation between the elec-trons in a negative hydrogen ion: theonly way both negatively charged par-ticles can be bound to a singlepositively charged proton.

Such metal hydrides offer clear ad-vantages compared to other switchableoptical systems, such as the transitionmetal oxides or the electrochromic bluebronzes, according to Griessen, includ-ing a faster switching time than anyother electrochromic material and ahigher contrast between the metallic re-flecting state and the transparent state.For example, hydrogen- intercalatedmetal oxide films, upon the absorptionof hydrogen, showed lower electricalresistivity at maximum doping, wereonly moderately conductive, and whilethe transparent sample changed to adark blue color, it remained essentiallytransparent.

Scientists at Philips Research Lab areworking on applying the transition pro-cess to solid state devices, in particularmetal hydride switches. By selectingappropriate alloys, the Philips team wasable to construct an optical device withthree different optical states: a colorneutral transparent state; a black ab-sorbing non-transparent state; and ametallic reflecting non-transparentstate. Each can be used to optimizecurrent applictions of electrochemicaldevices. For example, large area opti-cal coatings with switchable propertiescould be used to make transmissionvariable architectural glass, such thatwindows in buildings could bechanged from transparent to reflectivemode.

Window ’97: The Latest on FastSwitchable Mirrors

X-Ray Microprobes Offer New Tool forMaterials Science

to look deep into bulk objects, makingthem the dominant probe for determin-ing the three- dimensional atomicstructure of large single crystals,including organic compounds such ashemoglobin, insulin and DNA, as wellas simple inorganic compounds likesilicon and indium phosphide.

Janos Kirz and Chris Jacobsen ofSUNY-Stony Brook reported that theyhad for the first time produced two-dimensional images showing thedistribution of DNA and protein insperm from bulls and other mammals.Kirz reported that producing the im-ages in the temperature range of liquidnitrogen can keep the tissuesfrom showing damage from the x-rays,and predicted that his system will be a

stepping stone to developing ways tocreate three- dimensional images. “Ourgoal is to image flash-frozenhydrated cells and subcellular struc-tures such as nuclei andchromosomes in three dimensions,without the need for fixation,sectioning, or staining,” he said. He alsohopes to obtain chemical informationwith the spatial resolution set by thesize of the microprobe, and to visual-ize labels and markers whichbiologists may wish to attach to struc-tures of particular interes.

In separate atom-scale investigationsemploying x-ray beams with 5-10 mi-cron diameters, Columbia and IBMresearchers are determining how theflow of electricity through pure

June 1997 APS News

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aluminum wires (highly similar to those in computer chips) can eventually breakthe wires or cause them to malfunction. Using a 5-micron-diameter x-ray beamat the Brookhaven synchrotron, Slade Cargill at Columbia reported the first real-time measurements of the stresses that occur when electric current travelingthrough an aluminum wire displaces atoms in the wire, and monitor the gapsand bulges that develop.

The irregularities resulting from this “electromigration” effect are expected tobe a problem in the ever-shrinking aluminum-based wires of future-generationcomputer chips, which are 40 times smaller today than they were 30 years ago.In the past such problems were solved by using new combinations of metals, bylimiting the current levels and wire lengths, and by encapsulating the wires inrigid insulating materials. These ”solutions can no longer be relied upon, ac-cording to Cargill, who maintains that better understanding, better materialsand better device designs are needed for the next generation of microelectronicdevices.

For the past 25 years, biochemistsand biophysicists have studied themechanisms by which a protein knownas bacteriohodopson acts as a “pump”for protons, upon which most biologi-cal life processes are heavily dependentfor the transport of ions, neurotrans-mitters, enzymes, wastes and otherbiomolecules. However, in recentyears, bacteriohodopsin has attractedthe attention of scientists interested inusing biological materials to performtechnological functions, such asexpoiting the protein’s photoelectricproperties to manufacture photodetec-tors, or its optical properties tomanufacture “electronic ink” for com-puter displays.

“Natural materials often perform verycomplex functions that cannot be eas-ily obtained from manufacturedmaterials such as semiconductors,” saidPaul Kolodner (Lucent Technologies),who spoke at a Wednesday afternoonsession. “They have been optimized forthese functions by billions of years ofevolution and often perform better thanany human-designed material could.”And unlike devices such as integratedcircuits, which require many time-con-suming, high-precision and expensivemanufacturing steps, organisms manu-facture biological materials all bythemselves.

Bacteriohodopsin is an intensely-purple-colored protein molecule foundin the cell membrane of halobacterium,which grows in salt marshes. The pro-tein is photosynthetic and can be usedby the bacterium to produce matabolicenergy. Bacteriohodopsin is producedwhen the cell senses that chemicalnutrients are scarce. Specifically, itfunctions by “pumping” protons across

the cell membrane of the bacterium inresponse to illumination; these protonsare then used to initiate metabolicchemical reactions.

Just as thin films of bacteriohodopsinproduce electric fields when illumi-nated, they can be made to change theiroptical properties — in particular theircolor — when acted on by an electricfield, a property known aselectrochromism. Normalbacteriohodopsin exhibits a weak formof electrochromism. However, certainmutant halobacteria producebacteriohodopsin which potentially ex-hibits very strong electrochromism, inwhich the color changes from blue topale yellow. “If this property can beenhanced and generalized to othercolor combinations, this materialscouldbe used as an electrically addres-sable pigment, or ‘electronic ink,’” saidKolodner.

The obvious potential use for “elec-tronic ink” is in computer displays.According to Kolodner, abacteriohodopsin is sandwiched be-tween glass plates that contain arrays ofa large number of electrodes. A page oftext or a color image is written electri-cally on the protein film by applying thecorresponding array of voltages on theelectrodes, similar to the technologyused in liquid-crystal displays for laptopcomputers. The difference is that theelectronic ink gets its color bym reflect-ing ambient light, whereas the laptopdisplays require an internal light sourceswhich is a drain on the computer batter-ies. Thus, using computer displays basedon bacteriohodopsin “electronic ink”may make an important contribution tothe serious problem of battery lifetimein portable computing.

Manufacturing “Electronic Ink” fromModified Bacteriorhodopsin

Self-Organized CriticalityObserved in Brain Cells

In experiments which may provide new insight into how healthy brain cellssuccessfully communicate over long distances, scientists have found that a sys-tem of cultured rat brain cells produces spiral-shaped chemical waves ofcharacteristic sizes which can be described by a mathematical model knownas ”self-organized criticality.”

In the late 1980s, physicist Per Bak of Brookhaven National Laboratory intro-duced the idea of self-organized criticality, in which certain systems (e.g., a pileof sand grains) can reach a critical state in which the system can exhibit a radicalchange of behavior such as producing avalanches of all sizes by virtue of itsvery nature (the internal reorganization of its grains) and not by adjusting anexternal parameter.

In what is perhaps the first experimental evidence for a biological example ofself-organized criticality, Ann Cornell-Bell of Viatech Imaging in Connecticut hasfound that a system of cultured rat brain cells with the proper level of noise —corresponding to random firings of nerve cells — produces spiral-shaped waves(the propagation of a local chemical imbalance, observed by influxes of calciumions into the affected cells) of characteristic sizes.

Specifically, the Viatech researchers studied interactions between astrocytes,star-shaped cells that are closely associated with nerve cells, and can help regu-late the flow of chemical ions into and out of the cell. When a neurotransmitterknown as Kainate binds to an astrocyte, this can cause an influx of soduim atomsinto the cell. To compensate for thei imbalance, the cell draws in a flood ofcalcium atoms which are made to fluoresce and are detected by video camera.This state of imbalance can spread to other cells, thereby causing neighboringcells to draw in calcium ions of their own. The local imbalance propogates asa spiral wave, which are known to exist in many biological systems, such ascontraction waves in heart muscles of rabbits and rats, and in growing bacterialcolonies.

The waves follow the mathematical patterns which typify self-organized sys-tems, and agrees with a recent theory developed by Peter Jung of Georgia Techto establish the notion of spatiotemporal stochastic resonance. Originally con-ceived as a simple model for an excitable medium in contact with anoisy environment, the theory assumes a spatially distributed system with a reststate and an excited state, such that local excitation can spread through themedium, forming excitation waves. The theory’s agreement with the Viatechexperiments suggests that self-organized criticality might play a role in brainfunctions, according to Jung. “It is not the firing of a single nerve cell, or thechemical imbalance in an individual cell which is important,” he said. “It is thecollective properties of the complex system of cells which is important for itsproper functioning.”

Interestingly, follow-up imaging experiments using cells from excised humanepileptic tissue produced waves with significantly different behavior. Epilepsi isa condition where there is a dramatic increase in nerve cell activityand consequently often extremely high levels of neurotransmitter present, ac-cording to Cornell-Bell. Films from these experiments show extremely high activitywhere cells literally flash with calcium spikes.

Force detection with atto-newtonprecision has been achieved by an IBM-Stanford team of physicists led byDaniel Rugar of IBM. This work, re-ported during a Monday morningsession, was carried out with a mag-netic resonance force microscope(MRFM), a device that combinesnuclear magnetic resonance technologywith probe microscope technology.This new instrument holds the prom-ise of revolutionizig the study ofbiological processes at the molecularlevel and adding an entire new dimen-sion to the study of electronic materialsat the atomic level.

Magnetic Resonance Force Micros-copy (MRFM) brings togetherprobe-microscope (STM, AFM) technol-ogy with magnetic resonance (MRI,NMR, ESR) technology. The goal hereis nothing less than the ability to make3-dimensional, non-destructive, in-situ,atomic-resolution images of atoms,molecules, defects in solids, dopantsin semiconductors, and binding sitesin viruses. According to John Sidles ofthe University of Washington, who firstsuggested the device in 1991, the sig-nificance of MRFM research derivesmainly from the existence of a “gap” inimaging technology capabiities in the

size range of 1-100 angstroms, a rangethat encompasses biological moleculesand nanoscale electronic devices.

In the case of bio-medical research,modern techniques can render the mo-lecular sequences for many proteins,but full knowledge of the molecularstructure is usually lacking. A primeexample is the HIV virus, which isknown to contain nine genes whichencode at least 14 function proteins thatfall withint the 1-100 angstrom sizerange. The proteins are readily pro-duced in the laboratory, yet after morethan decade of stidy, the majority ofHIV proteins still have unknown struc-ture, and in many cases, unknownfunction. “This lack of knowledge re-flects the limited capacity of presentinstruments to image objects in the 1-100 angstrom range,” said Sidles.“MRFM technology was conceived spe-cifically to fill this imaging gap.”

In the IBM-Stanford setup, a thin sili-con cantilever, 230 microns long butonly 60 nm thick, is poised above atiny sample. Under the additional in-fluence of fields from an RF coil, amagnetic particle mounted on the can-tilever interacts with tiny volumes ofmagnetic atoms in the sample. Underjust the right circumstances the particleon the cantilever will begin to reso-nantly oscillate like a diver on a divingboard; the cantilever’s movement shiftsa laser interference pattern viewedthrough an optical fiber. Using thisdevice, the group was able to measureforces with a resolution of 7 atto-New-

tons (7 x 10^-18N), the most sensitiveforce measurement ever made with aprobe microscope. With further refine-ment the MRFM process will detectsingle spins, and Rugar hopes to mapthe spins of electrons in dispersed de-fect sites in silica.

Key to the achievement was thedevelopment of ultra- sensitive canti-levers, 1000 times thinner than a humanhair and invisible to the naked eye. Theteam statrted with an ultra-thin layerof silicon bonded onto a layer of sili-con oxide coating a silicon wafer. Theythen etched cantilever shapes onto theultra-thin layer and chemically removedthe underlying layers of oxide. Accord-ing to Rugar, silicon was selected tominimize the mechanical damping thatoccurs when the cantilever vibrates,and because it is compatible with semi-conductor processing techniques.

The manufacturing process is sodelicate that the researchers could notuse normal dying techniques after thefinal fabrication step. “The surface ten-sion of the water is strong enough sothat as it dries, it bends the cantileversinto ‘U’ shapes, causing them to reat-tach to the underlying material,” saidRugar. The team circumvented theproblem by using an exituc biologicaltechniques called critical point drying,which uses liquid carbon dioxide athigh pressures.

Sidles emphasizes the possible medi-cal and biological research applications,observing that the structure of someproteins can be worked out with nearly

Scientists Detect Atto-Newton ForcesUsing MRFM

APS News June 1997

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atomic resolution by crystallizing a sample and then interpreting the pattern of xrays diffracted by the crystal. Other notable proteins, however, do not lendthemselves to this process. Moreover, ordinary force microscopes cannot imageinteresting molecules residing in clefts of biological structures. MRFM, by con-trast, will supply 3D images of the hardest-to-get-at molecules, providinginformation for medical and drug-design research.

A Los Alamos-Caltech group, represented by Chris Hammel of Los Alamos isapplying MRFM to the study of multi-layer electronic devices, which could haveimportant implications for magnetic information storage technology. Layers ofmagnetic material sandwiched with layers of non-magnetic layers such as cop-per or gold are used as variable resistors. The thickness and roughness of theinterface between layers affects the performance of magnetic disks used in com-puters. MRFM will be able to reveal the irregularities between the layers and therelated local magnetism and electrical properties, without having to cut or de-stroy the samples. Eventually Hammel’s probe will be able to map buriedstructures, such as defects in circuit elements. He uses a stiffer, faster-oscillatingtip than the IBM version; this does not necessarily improve the force sensitivitybut would greatly speed up data acquisition.

Severl MRFM groups are presently working toward the detection and imagingof individual electron moments which, if successful, will take magnetic reso-nance imaging to its ultimate limit: one spin in one voxel. However, Sidlesemphasized that instrument development is a slow process, and that none of themajor biomedical technologies used today were fully developed in less than 25years. In comparison, scanning probe microscopy at the atomic scale has onlybeen around since 1982. “Based on historical precedent, it will likely be at leastanother decade before scanning probe technologies like MRFM achieve main-stream status in biomedical research,” he said.

Editor’s Note: Some MRFM figures are available on the World Wide Web at:http://www.aip.org/physnews/graphics/