ISSN:0031-9228    

DOI:10.1063/1.2913880

出版商:AIP    

年代:1980

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2913851

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

“For the discovery of violations of fundamental symmetry principles in the decay of neutral K mesons,” the Royal Swedish Academy of Sciences has awarded the 1980 Nobel Prize in Physics to James W. Cronin of the University of Chicago and Val L. Fitch of Princeton University. This year the prize is worth $210 000.

ISSN:0031-9228    

DOI:10.1063/1.2913852

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

While we accelerate elementary particles and ions by the most advanced electromagnetic means, our standard techniques for propelling macroscopic objects—from birdshot to interplanetary vehicles—are not very different from those in use since the introduction of gunpowder from China. But propulsion by chemical combustion suffers from severe limitations that are keenly felt by people interested in space travel, inertial‐confinement fusion, and even such prosaic pursuits as artillery.

ISSN:0031-9228    

DOI:10.1063/1.2913853

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

It would presumably take an order of magnitude less beam energy to run an inertial‐confinement thermonuclear reactor with ion beams than with electron beams. But until last year the technological problems of producing and focusing a sufficiently intense light‐ion beam have kept the emphasis of particle‐beam fusion research on electron‐beam devices. The largest particle‐beam fusion machines, at Sandia in Albuquerque and at the Kurchatov Institute in Moscow (still under construction), were originally designed to implode deuterium‐tritium pellets with beams of 2‐MeV electrons.

ISSN:0031-9228    

DOI:10.1063/1.2913854

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

Diffraction effects at wavelengths on the order of angstroms have been known since Max von Laue's demonstrations of x‐ray diffraction in 1912. Interference between well‐separated, coherent beams, however, is much more difficult to arrange.

ISSN:0031-9228    

DOI:10.1063/1.2913855

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

Fifty years ago there was no way for physics teachers to communicate with each other, no way to share either their successes or their frustrations. Teachers had no professional standing as such, and teaching itself seemed to merit little if any recognition or reward. In December 1930 the American Association of Physics Teachers was organized as “an informal association of those interested in the teaching of physics.” By the end of 1931 the Association had grown from an original 42 to more than 500. The AAPT now has more than 10 000 members and serves the entire physics community.

ISSN:0031-9228    

DOI:10.1063/1.2913856

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

The physics of phonons, or elastic waves, with gigahertz to terahertz frequencies is currently gaining considerable attention. A variety of new phonon techniques has been developed over the past few years as a result of new technologies and materials; they include notable advances in the generation of tunable monochromatic phonon beams at terahertz frequencies, in the creation of “phonon optics” devices such as reflection gratings for ultrasonic waves, and in the interaction of high‐frequency phonons with impurities and free carriers in semiconductors. This recent activity was particularly evident at the Third International Conference on Phonon Scattering in Condensed Matter held last year at Brown University.

ISSN:0031-9228    

DOI:10.1063/1.2913857

出版商:AIP    

年代:1980

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2913858

出版商:AIP    

年代:1980

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2913861

出版商:AIP    

年代:1980

数据来源: AIP