ISSN:0031-9228    

DOI:10.1063/1.2809981

出版商:AIP    

年代:1991

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2809982

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

As the date of the APS March meeting draws near, the conflicting results of two key experiments first aired by condensed matter physicists at last year's gathering are no closer to being resolved. Indeed a third experiment, reported this fall, has further clouded the picture. The conflicting evidence concerns whether or not high‐temperature superconductors alter either the direction or ellipticity of polarized light passing through them. Such behavior might signal the breaking of time‐reversal invariance in these new oxide materials—precisely the effect predicted by proponents of theories that invoke anyons, or exotic objects obeying fractional statistics, to explain the superconductivity.

ISSN:0031-9228    

DOI:10.1063/1.2809983

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The picture at right shows a gaseous ring, 1.37 light‐years in diameter, surrounding the remnant of supernova 1987A. This image, taken by the European Space Agency's Faint Object Camera aboard the Hubble Space Telescope, achieves a diffraction‐limited resolution of 0.07 arcseconds, despite the Hubble's much lamented spherical aberration.

ISSN:0031-9228    

DOI:10.1063/1.2809984

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The birth of national research laboratories in the US is marked by the founding of the Bureau of Standards at the turn of the 20th century. As the country was about to enter World War I, the government organized the National Advisory Committee for Aeronautics, which actually performed R&D to help the fledgling field of aviation get airborne, and the Naval Consulting Board that quickly fostered the Naval Research Laboratory. Both NACA and NRL were formed to advance the country's defenses. While government labs may have seemed strange in a nation dedicated to free enterprise, the concept of research laboratories was familiar to corporate America. By World War I, research labs were spewing forth new products at General Electric, Westinghouse Electric, DuPont, Eastman Kodak, Corning Glass Works and American Telephone and Telegraph. It was World War II that provided the impetus for a proliferation of government laboratories. One of the earliest was the Radiation Laboratory at MIT, where the British invention of microwave radar was transformed from an engineering curiosity to a practical technology. The Advisory Committee on Uranium, initiated at the urging of prominent physicists in 1939, after nuclear fission was discovered in Germany, led the Army to organize the Manhattan Project in 1943 to produce atomic bombs. The Manhattan Project itself spawned a remarkable network of laboratories to advance nuclear weapons and perform fundamental research: Los Alamos, Oak Ridge, Argonne, Lawrence Radiation Laboratory, Ames, Bettis and Brookhaven. Soon after the war, these labs were designated by Congress as government‐owned and contractor‐operated, placed under the aegis of the civilian‐dominated Atomic Energy Commission and managed by either major universities or industrial firms. Aware of the advantages of using high technology in modern warfare, the armed services had initiated their own laboratories to further their military missions. Some were organized before and during the war, others after the postwar creation of the Defense Department. Six months after the Soviet Union launched its first Sputnik in 1957, NACA was transformed into NASA, which produced another group of national laboratories.

ISSN:0031-9228    

DOI:10.1063/1.881279

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We live in a society shaped by science and technology. As our society evolves it will draw more and more upon science and technology to generate economic growth, to improve health and to enhance the quality of life. In order to provide adequate scientific and engineering personnel for our national needs and to sustain the knowledge base from which growth derives, careers in science and engineering must be attractive to our youth.

ISSN:0031-9228    

DOI:10.1063/1.881280

出版商:AIP    

年代:1991

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2809985

出版商:AIP    

年代:1991

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2809986

出版商:AIP    

年代:1991

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2809987

出版商:AIP    

年代:1991

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2809988

出版商:AIP    

年代:1991

数据来源: AIP