摘要:

There is reason to believe that unclassified (security‐wise) technical reports are issuing from the Government's defense‐related research and development program at a rate of the order of 25,000 distinct titles per year. These include the outputs of the Department of Defense, the Atomic Energy Commission, the National Advisory Committee for Aeronautics, and their respective numerous contractors. This heterogeneous mass of separates originates from hundreds of different laboratories and exhibits little uniformity of format, periodicity, arrangement, or technical stature. That its contents include an appreciable fraction of today's newest scientific information is generally recognized. Almost no reliable information has been available, however, on the extent to which the scientifically‐significant portion of this material is finding its way into the professional journals or other information media available to research scientists and teachers who do not happen to be affiliated in one way or another with government‐supported research.

ISSN:0031-9228    

DOI:10.1063/1.3067440

出版商:AIP    

年代:1952

数据来源: AIP

摘要:

The spectroscopist in the past has been a fortunate fellow. When he could no longer find something new to measure with his old spectrometer (or if he became bored with repeated use of the same old frequencies) he could always move on to a new place in the spectrum, provided of course that he could generate and detect radiation there. Until very recently there was a vast unexplored island in the electromagnetic spectrum, the region between the infrared waves and the conventional radio waves, now known as the microwave region

ISSN:0031-9228    

DOI:10.1063/1.3067441

出版商:AIP    

年代:1952

数据来源: AIP

摘要:

The direct measurement of gamma‐rays only yields about half the picture in the study of nuclear energy levels. The other, and indeed to most physicists more familiar, half concerns the &bgr;‐rays, including in this term both the continuous &bgr;‐ray spectrum and the line spectrum by “conversion”, either internal or external. Ever since 1948, therefore, we have been much occupied with the design and construction along rather novel lines of a high precision helical focusing magnetic &bgr;‐ray spectrometer planned as a companion instrument to the crystal diffraction spectrometer as regards absolute precision and accuracy. We have only very recently completed this instrument and made the first tests on it which indicate that it will meet all our expectations both as to high absolute accuracy and high luminosity and sensitivity to weak sources.

ISSN:0031-9228    

DOI:10.1063/1.3067417

出版商:AIP    

年代:1952

数据来源: AIP

摘要:

Ever since Kamerlingh‐Onnes discovered in 1911 that the electrical resistance of mercury abruptly vanished at a temperature just a few degrees above the absolute zero, the phenomenon of superconductivity has presented an intriguing challenge to physicists. Subsequent experiments by Onnes and others definitely established that the resistivity of a superconductor, if at all finite, must be immeasurably small, and less than10−20 ohm cm.Consequently the superconductor is assumed to have zero resistance. Onnes soon found that the superconducting property was not peculiar to mercury but was characteristic of a sizable group of metals. Twentyone of the metallic elements are known to be superconductors as are innumerable alloys and intermetallic compounds. The known superconductors are exhibited in Fig. 1 and are seen to fall into definite areas of the periodic table. None of the monovalent metals are observed to be superconducting, at least down to temperatures of the order of a few tenths of a degree absolute.

ISSN:0031-9228    

DOI:10.1063/1.3067418

出版商:AIP    

年代:1952

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.3067420

出版商:AIP    

年代:1952

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.3067421

出版商:AIP    

年代:1952

数据来源: AIP

摘要:

One of the summer's more important but almost unnoticed events occurred on September 6th, when Manpower Policy No. 8 was issued by Acting Secretary John R. Steelman of the Office of Defense Mobilization to define the government's position regarding the training and use of scientific and engineering manpower. This over‐all policy, recommended by the interagency Manpower Policy Committee, its Committee on Specialized Personnel, and the national Labor‐Management Manpower Policy Committee of the Office of Defense Mobilization, assigned to government agencies the responsibility for making specific contributions to the program for the utilization and training of scientists and engineers. While the policy recognized that many of its recommended activities were already under way in individual industrial firms, educational institutions, professional organizations, and in government, it is also clear that much remains to be done before solutions can be found for the underlying problems which have made such a policy statement necessary.

ISSN:0031-9228    

DOI:10.1063/1.3067423

出版商:AIP    

年代:1952

数据来源: AIP

摘要:

A research program aimed at attempting to determine the structure of our galaxy through a study of the great clouds of hydrogen which float in the Milky Way is soon to be initiated by the Harvard Observatory under the direction of Bart J. Bok and Harold I. Ewen. Plans have been announced for construction of a radio telescope at the Observatory's Agassiz Station, and work on a twenty‐five‐foot parabolic reflector antenna and on housing for the necessary electronic and control gear is already in progress. Radiation from the hydrogen clouds (at a wavelength of 21 cm) was first discovered in 1951 by one of this year's Nobel prize winners, Edward M. Purcell of the Harvard physics department, and by Dr. Ewen, now a research associate at the Observatory. A short time later confirmation was provided from Holland, where J. H. Oort and C. A. Muller detected the same radiation during observations made at the Kootwijk Radio Observatory. The Dutch scientists are reported to have in operation apparatus with which they have begun to trace the spiral structures in the remote parts of our galaxy. Similar research is also being carried out at the Radio Physics Laboratory in Sydney, Australia.

ISSN:0031-9228    

DOI:10.1063/1.3067427

出版商:AIP    

年代:1952

数据来源: AIP

摘要:

Two nuclear physicists who in 1945 discovered independently the phenomenon that is referred to either as “nuclear induction” or “nuclear magnetic resonance absorption” have been named to share this year's Nobel Prize in physics. Felix Bloch, professor of physics at Stanford University, and Edward M. Purcell, associate professor of physics at Harvard, were selected by the Swedish Academy of Science on November 6th to receive the award in recognition of their contributions to an improved understanding of the structure and forces of atomic nuclei.

ISSN:0031-9228    

DOI:10.1063/1.3067428

出版商:AIP    

年代:1952

数据来源: AIP

摘要:

The first privately‐financed research organization devoted primarily to the development of atomic power for industrial purposes, the Walter Kidde Nuclear Laboratories, has begun research operations at its recently constructed laboratory near Garden City, on Long Island. The new laboratory, housed in a brick structure of modern design, with laboratory area for work in physics, chemistry, metallurgy, radiochemistry, and materials testing, is expected to be in full operation by the latter part of 1953, by which time it is expected that a minimum staff of one hundred will be employed. The stated objectives of the organization are (1) the development of commercial atomic power, with particular emphasis on original research and development in the field of low‐cost nuclear reactors, (2) cooperation on a contract basis with government agencies and their contractors in the development and design of atomic facilities, and (3) collaboration with private industrial organizations, laboratories, and others interested in the application of the nuclear sciences to specific problems.

ISSN:0031-9228    

DOI:10.1063/1.3067432

出版商:AIP    

年代:1952

数据来源: AIP