摘要:

The American Institute of Physics is a not‐for‐profit membership corporation chartered in New York State in 1931 for the purpose of promoting the advancement and diffusion of the knowledge of physics and its application to human welfare. Leading societies in the field of physics and astronomy are its members. AIP's activities include providing services to its Member Societies in the publishing, fiscal, and educational areas, as well as other services which can best be performed by one operating agency rather than dispersed among the constituent societies.

ISSN:0031-9228    

DOI:10.1063/1.2811267

出版商:AIP    

年代:1988

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2811268

出版商:AIP    

年代:1988

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2811269

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

Yet another surprise from the quantum Hall effect. Since its first observation in 1980 by Klaus von Klitzing and coworkers, this remarkable quantum behavior of two‐dimensional electron systems at low temperature and high magnetic field has not ceased to challenge theorists with the totally unexpected. The first great surprise was the observation of broad plateaus of constant Hall conductivity at quantized values that agreed with a manifestly simplistic theory to a quite incredible accuracy of a few parts in108.Von Klitzing won the 1985 Nobel Prize in Physics for his discovery.

ISSN:0031-9228    

DOI:10.1063/1.2811270

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

Supernova 1987a, which appeared as a naked‐eye object 23 February 1987 in the Large Magellanic Cloud (see the article by David Helfand inPHYSICS TODAY, August, page 25), continues to challenge observers and theorists.

ISSN:0031-9228    

DOI:10.1063/1.2811271

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

In 1932 John Cockcroft and Ernest Walton developed an electrostatic accelerator at the Cavendish Laboratory, thus starting the modern age of particle accelerators. Since then, our capabilities have increased tremendously, as may be seen in figure 1, which shows the energy of acceleratorsthrough the years. There has been an exponential increase in energy (the “Livingston curve”)—but it is the envelope that displays this exponential behavior, not any particular technique. One can conclude that if we are to stay anywhere near the Livingston curve, new techniques need to be developed.

ISSN:0031-9228    

DOI:10.1063/1.881151

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

Vision is awe inspiring. The wondrous nature of this sensory process becomes clear when we consider just a few of its features. In the terminology of today's technology, the human visual system has a set of stereoscopic foreoptics that are instantly and automatically focusable to a few centimeters and are fully corrected for geometric aberrations, a servo‐controlled two‐axis scanning mechanism, a millisecond framing rate, sensitivity to brightnesses varying by a factor of 100 billion, the ability to detect a single photon, nearly 100&percent; quantum efficiency and a spatial as well as temporal image processor that could not be matched by the fastest supercomputer.

ISSN:0031-9228    

DOI:10.1063/1.881152

出版商:AIP    

年代:1988

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2811272

出版商:AIP    

年代:1988

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2811273

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

Despite the effects of the Depression on the institutions that supported its work, the American physics community of the 1930s was booming intellectually. In particular, many of its members were contributing significantly to the rapid emergence of nuclear physics as a distinctive field of research. Among the most active of these participants was Merle Antony Tuve.

ISSN:0031-9228    

DOI:10.1063/1.881153

出版商:AIP    

年代:1988

数据来源: AIP