ISSN:0031-9228    

DOI:10.1063/1.2913925

出版商:AIP    

年代:1980

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2913894

出版商:AIP    

年代:1980

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2913901

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

Although we know of no symmetry in nature that requires the conservation of baryon number, the stability of ordinary matter would appear to attest to the absolute stability of the proton. But we're soon to have a closer look. Two groups of high‐energy physicists are preparing to descend into mines in Ohio and Utah, to look for proton decays with detectors several orders of magnitude more sensitive than any employed for such a search in the past.

ISSN:0031-9228    

DOI:10.1063/1.2913903

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

When the first beams begin circulating in PEP at the Stanford Linear Accelerator Center in March, both sides of the Atlantic will have storage rings producing electron–positron collisions at center‐of‐mass energies up to 36 GeV. If the rich history of the previous generation ofe+e−colliding‐beam storage rings is any guide, this new energy regime should provide an abundance of interesting physics. But PEP and its Germany cousin PETRA (at DESY, Hamburg) still fall short of the energy range 90–150 GeV that particularly intrigues particle physicists. The European high‐energy community hopes to have a storage ring (LEP) of gargantuan size and price tag, capable of achieving these energies by about 1988.

ISSN:0031-9228    

DOI:10.1063/1.2913904

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

Nearly a quarter‐century after the first production of antiprotons in the laboratory, a group of experimenters using a balloon‐borne superconducting‐magnet spectrometer believes they have detected a statistically significant number of these particles in cosmic rays entering the Earth's upper atmosphere. The observation of cosmic‐ray antiprotons—believed to be secondary particles, not primordial antimatter from the Big Bang or from antistars—has confirmed theorists' predictions of the ratio of antiprotons to protons in the interstellar medium and has greatly extended the antiproton's measured lifetime. The observation is expected to furnish new information about the amount of matter traversed by the cosmic rays and the mechanism of their acceleration.

ISSN:0031-9228    

DOI:10.1063/1.2913905

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

To the physicist casually interested in gravitation, a black hole is a passive object that swallows anything near it and cannot be made to disgorge it; it absorbs but cannot emit. At the close of the last decade the experts shared this view. Recently, however, this simple picture has changed entirely. Perhaps no single development highlighted more the new views about black holes than the quantum argument presented by Stephen Hawking of Cambridge University in 1974 that a black hole must radiate spontaneously with a thermal spectrum. The importance of this phenomenon is not so much in possible practical applications, not even in its astrophysical implications, but rather in that it has confirmed earlier suspicions that gravitation, thermodynamics and the quantum world are deeply interconnected. This connection, which might be symbolized by the thermodynamic engine shown in figure 1, engenders hope that we may achieve a synthesis of these three branches of physics in our time and bears witness to the profound unity of physics, a unity too often veiled in an age of increasing specialization.

ISSN:0031-9228    

DOI:10.1063/1.2913906

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

Most scientific studies of imperfect solids concentrate on the properties of individual isolated defects. Such properties include their electronic structure, as shown by optical and spin‐resonance data, formation energies, and diffusion parameters. Yet these properties alone do not always determine those practical applications of solid‐state physics that exploit the behavior of defects. The principal extra ingredients can often be described as defect processes—how defects interact with each other and how the imperfect lattice evolves. That is, the time‐dependent behavior of the imperfect solid, not just its static properties, affects how it can be used.

ISSN:0031-9228    

DOI:10.1063/1.2913907

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

The decade of the 1970's has been a time of turmoil and transition for the support of physics and physicists, especially of young physicists just completing their graduate years. Science, the Endless Frontier, had come to have financial horizons quite close in during the late 1960's and early 1970's. A whole generation of physicists had become accustomed to automatic careers, in which demand so far exceeded supply that the greatest problem was to choose among desirable alternatives. The great expansion of higher education had created limitless opportunities in the mode most familiar to the graduate student, and academic research—perforce with some teaching—became the normal career goal.

ISSN:0031-9228    

DOI:10.1063/1.2913908

出版商:AIP    

年代:1980

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2913909

出版商:AIP    

年代:1980

数据来源: AIP