摘要:

In the three years which have elapsed since the discovery of high‐field superconductors, considerable effort at various laboratories has been directed toward the development and production of superconducting magnets. Commercial magnets wound with Nb‐Zr wire are now available for fields up to 60 kG (up to 90 kG if supplemented by Nb‐Ti wire); test magnets fabricated fromNb3Sncompound have already surpassed the 100‐kG mark. At present, superconducting magnets are used most extensively in solid‐state physics experiments that require a simple field configuration in a modest volume—longitudinal field over a one‐inch bore is typical. The superconducting magnet of this type is compact and inexpensive, and it will find its way into almost every basic science laboratory. Though impressive, present achievement and future outlook of superconducting technology is somewhat disappointing to those who anticipated immediate applications of high‐field superconductors in fusion research, high‐energy physics, and the whole range of ac devices, including transformers, generators, and transmission lines. Production and use of large‐volume magnets have been hampered by the unexpected phenomenon of current degradation—superconducting wires often will carry considerably smaller current when they are wound into magnets. This is caused by instabilities rather basic to the present high‐field materials. Particularly discouraging are the poor ac characteristics of these materials. Nevertheless, superconducting magnets will figure more prominently in future high‐field installations as they generally yield over‐all economy compared to the conventional magnets. While initiating a new technology, the discovery of high‐field superconductors has also precipitated new understanding (and, in some cases, new physics) in the field of hard superconductivity. After reviewing the present status of superconducting magnets, I shall devote the latter half of this article to an exposition of hard superconductivity.

ISSN:0031-9228    

DOI:10.1063/1.3051796

出版商:AIP    

年代:1964

数据来源: AIP

摘要:

The twentieth anniversary of the founding of the Division of High‐Polymer Physics of the American Physical Society is an appropriate time to review the progress of polymer physics over the last two decades, and to re‐evaluate the hopes of the founders and the present need for the Division. The continuing need for our Division perhaps is best shown by the fact that each of the last two meetings have set new records for the number of papers presented. Much of this progress is due to the officers who have contributed so much of their time and effort to the Division. Those who served in the first decade were recognized in an earlier review. The officers of the last decade are shown in the accompanying table. We are indebted to all these men for their work to keep the Division running, and thus promote the progress of polymer physics.

ISSN:0031-9228    

DOI:10.1063/1.3051798

出版商:AIP    

年代:1964

数据来源: AIP

摘要:

The data in this report show trends in the number of people studying physics in high schools, undergraduate colleges, and graduate schools and show the relationship between degree production and the increase in professional physics manpower.

ISSN:0031-9228    

DOI:10.1063/1.3051801

出版商:AIP    

年代:1964

数据来源: AIP

摘要:

From the 20th to the 22nd of April 1964, 85 chemists and physicists from England, Germany, Japan, Canada, and the United States gathered on the campus of Duke University for a symposium on chemical reactions in shock tubes. This meeting served to outline clearly both the contributions which shock tubes have made to chemical research and the prospects which may be anticipated in the near future.

ISSN:0031-9228    

DOI:10.1063/1.3051805

出版商:AIP    

年代:1964

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.3051808

出版商:AIP    

年代:1964

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.3051815

出版商:AIP    

年代:1964

数据来源: AIP

摘要:

The photographs of diffraction patterns were inadvertently misplaced in Fig. 2 of “Low‐Energy Diffraction,” by Lester H. Germer, which appeared in Physics Today (July 1964, p. 19). The above reproduction shows the correct sequence of the diffraction patterns for which the caption read: Diffraction patterns from a tungsten (110) face. A. Clean, 98 volts; B. With half monolayer of oxygen atoms, 115 volts; C. With three‐fourths monolayer of oxygen atoms, 100 volts; D. With full monolayer of oxygen atoms, 75 volts.

ISSN:0031-9228    

DOI:10.1063/1.3051820

出版商:AIP    

年代:1964

数据来源: AIP

摘要:

The Irving Langmuir Laboratory for Atmospheric Research, established last year by the New Mexico Institute of Mining and Technology, is currently engaged in a variety of research programs relating to cloud physics and thunderstorm phenomena. During the International Quiet Sun Years of 1964 and 1965, the Laboratory is cooperating with the Joint Committee on Atmospheric and Space Electricity of the International Union of Geodesy and Geophysics by making data available for use in an international effort to correlate the basic parameters of atmospheric electricity on a world‐wide scale.

ISSN:0031-9228    

DOI:10.1063/1.3051837

出版商:AIP    

年代:1964

数据来源: AIP

摘要:

A $15 million fund, intended for basic research in the physical sciences, has been established at the Massachusetts Institute of Technology. Money for the fund, which will be known as “The Alfred P. Sloan Fund for Basic Research in the Physical Sciences”, comes from a personal gift of $5 million from Mr. Sloan, which will be matched in equal amounts by a Sloan Foundation gift and another earlier Foundation grant to MIT. Considered one of the largest private gifts to research in recent years, the fund will approximately double the amount of money available at MIT for basic research. The object of the fund will be to help correct the imbalance existing between the resources of applied and basic research and, in general, to support research in those areas of the physical sciences that are not otherwise heavily subsidized.

ISSN:0031-9228    

DOI:10.1063/1.3051840

出版商:AIP    

年代:1964

数据来源: AIP

摘要:

DESY (otherwise Deutsches Elektronen‐Synchrotron), a 6‐BeV strong‐focusing electron synchrotron, started operating in Hamburg at the end of February. The German machine takes 40‐MeV electrons from a linear accelerator and sends them through a ring tunnel, 100 meters in diameter. Inside the tunnel there are 24 radially focusing magnets and 24 radially defocusing magnets, with 16 straight accelerating sections between. DESY produces between 1 and3×1010 electrons/pulseor from 5 to15×1011 electrons/second.So far, 4.8 BeV is the maximum particle energy available for continuous operation, although bursts of 6‐BeV electrons have been achieved without major trouble.

ISSN:0031-9228    

DOI:10.1063/1.3051861

出版商:AIP    

年代:1964

数据来源: AIP