ISSN:0031-9228    

DOI:10.1063/1.2810102

出版商:AIP    

年代:1991

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2810103

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Six years ago, John Simpson at the University of Guelph in Ontario reported a rather disquieting discovery. In the beta decay of tritium, he asserted, a small fraction of decay events appear to produce a neutrino weighing 17 keV. That's130,the mass of the electron—very much larger than anyone was looking for in the many attempts to find evidence for a nonvanishing neutrino mass in the end point of the electron energy spectrum from tritium decay.

ISSN:0031-9228    

DOI:10.1063/1.2810104

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Thermodynamics arose in the 19th century out of the attempt to understand the performance limits of steam engines in a way that would anticipate all further inventions. Claude Shannon, after World War II, analyzed the limits of the communications channel. It is no surprise, then, that shortly after the emergence of modern digital computing, similar questions appeared in that field. It was not hard to associate a logic gate with a degree of freedom, then to associatekTwith that, and presume that this energy has to be dissipated at every step. Similarly, it seemed obvious to many that the uncertainty principle,&Dgr;E&Dgr;t∼ℏ,could be used to calculate a required minimal energy involvement, and therefore energy loss, for very short&Dgr;t.

ISSN:0031-9228    

DOI:10.1063/1.881299

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Since the beginning of scientific inquiry the nature of light has played a vital role in our understanding of the physical world. Physicists have marveled at the dual nature of light as both corpuscle and wave; we have harnessed the remarkable coherent properties of light through the use of lasers; and the quantum mechanics of the interaction of photons with matter continue to provide fascinating avenues of basic research. In essence, any alteration of electromagnetism, the fundamental interaction overning atomic, molecular and condensed matter physics, will lead to fundamentally new phenomena in all these areas.

ISSN:0031-9228    

DOI:10.1063/1.881300

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

In observing its 40th anniversry last year, the National Science Foundation held a special symposium to celebrate its achievements and to look ahead to the next 40 years for the foundation as well as for all of science and technology in America. NSF's accomplishments are impressive. These include a major role in producing successive generations of scientists and engineers; in supporting pace‐setting research in a multitude of fields, including some, such as high‐temperature superconductivity, that it did much to initiate; and in monitoring the pulse of the nation's science and engineering enterprise.

ISSN:0031-9228    

DOI:10.1063/1.881301

出版商:AIP    

年代:1991

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2810105

出版商:AIP    

年代:1991

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2810106

出版商:AIP    

年代:1991

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2810107

出版商:AIP    

年代:1991

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2810111

出版商:AIP    

年代:1991

数据来源: AIP