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1. |
New Murray Hill Laboratory of Bell Telephone Laboratories |
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Journal of Applied Physics,
Volume 14,
Issue 6,
1943,
Page 249-257
Franklin L. Hunt,
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ISSN:0021-8979
DOI:10.1063/1.1714983
出版商:AIP
年代:1943
数据来源: AIP
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2. |
Frictional Phenomena. XIV |
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Journal of Applied Physics,
Volume 14,
Issue 6,
1943,
Page 258-270
Andrew Gemant,
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摘要:
IN this chapter technical applications of the solid friction concept in four different fields are discussed. These are: (1) mechanical engineering, (a) damping of unwanted vibrations in machinery—for instance, crank‐shaft vibrations, (b) vibrations excited by internal friction—for instance, whirl of rotating shafts; (2) metallurgy in which damping measurement promises to be a useful new tool; (3) rubber technology, as applied to automobile tires with regard to the heat generated therein; and (4) electrical engineering, specifically dielectric losses in electrical insulating materials.
ISSN:0021-8979
DOI:10.1063/1.1714984
出版商:AIP
年代:1943
数据来源: AIP
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3. |
Re´sume´s of Recent Research |
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Journal of Applied Physics,
Volume 14,
Issue 6,
1943,
Page 271-272
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PDF (154KB)
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ISSN:0021-8979
DOI:10.1063/1.1714986
出版商:AIP
年代:1943
数据来源: AIP
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4. |
On Torsion Combined with Compression |
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Journal of Applied Physics,
Volume 14,
Issue 6,
1943,
Page 273-283
P. W. Bridgman,
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摘要:
If a rod is twisted while subjected to longitudinal compression it will support without fracture angles of twist many‐fold greater and maximum torques somewhat greater than is possible in the absence of load. Under compressional load the curve of shearing stress against shearing strain rises to a maximum and then sinks with a long drawn out tail to an approximate asymptote. Fracture is never complete, but some coherence always remains, probably due to cold welding. The maximum torque is not marked by any visible beginning of fracturing or other discontinuity. The strain hardening curve in torsion, therefore, under proper circumstances passes through a maximum. The whole mechanism of strain hardening appears to be different in torsion and in tension, and reasons are given for anticipating such a difference because of the difference of the atomic kinetics in torsion and tension. It is shown in particular that the method of correlating tension and torsion through the ``octahedral'' coordinates which is applicable for small strains is not applicable to the large strains which are the subject of the present discussion. It is shown that the equations of conventional plasticity theory correctly reproduce certain qualitative aspects of the secondary longitudinal and radial flow which accompany twisting, but it is possible to establish large failures of isotropy not covered by the elementary theory. With regard to fracture, it is necessary to distinguish sharply between fracture in tension and in shear. The latter is not clean cut and it is probably possible to realize a continuous gradation of atomic disorganizations, culminating under proper conditions in complete shearing fracture.
ISSN:0021-8979
DOI:10.1063/1.1714987
出版商:AIP
年代:1943
数据来源: AIP
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5. |
A Tension‐Compression Device for Quantitative X‐Ray Diffraction Evaluation of Strain in Metals and a Calibrated Series of Aluminum Alloys |
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Journal of Applied Physics,
Volume 14,
Issue 6,
1943,
Page 284-290
George L. Clark,
George Pish,
Ralph Seabury,
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摘要:
An easily constructed apparatus is described for applying tension and compression stresses to metal and alloy samples while being subjected to x‐ray diffraction analysis. The back reflection technique is employed in which diffraction patterns can be photographed in five minutes or less. The apparatus and technique have been developed because of the increasing interest in the measurement of strain in a variety of metallurgical materials of primary war interest. A series of patterns on a familiar aluminum alloy under calibrated tension stresses is reproduced as an example by means of which evaluation of residual strains in large castings can be non‐destructively evaluated.
ISSN:0021-8979
DOI:10.1063/1.1714988
出版商:AIP
年代:1943
数据来源: AIP
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6. |
Studies on the Structure of Thin Metallic Films by Means of the Electron Microscope |
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Journal of Applied Physics,
Volume 14,
Issue 6,
1943,
Page 291-305
Robert G. Picard,
O. S. Duffendack,
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摘要:
A study was made of thin films of aluminum, cadmium, copper, gold, magnesium, and zinc using an RCA electron microscope capable of 30A resolving power. The films were formed by evaporation and condensation on collodion substrates in vacuum. An evaporating chamber was devised that permitted control of the temperature of the condensing surface. Photographs of the surfaces show that all the films are made of agglomerates of the metals separated by interstices of various widths. All evidence leads to the conclusion that the surface structure is explainable by assuming migration of the atoms over the surface. The observed structure can be used to explain the electrical conductivity, the optical reflectivity, and adsorptivity of thin films. Electron microscopic studies also provide a ready means of classifying surfaces according to the mobility of the atoms comprising them, and thus enable a rough estimate of the potential distribution over the surface to be made.
ISSN:0021-8979
DOI:10.1063/1.1714989
出版商:AIP
年代:1943
数据来源: AIP
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7. |
A Note on the Mutual Impedance of Antennas |
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Journal of Applied Physics,
Volume 14,
Issue 6,
1943,
Page 306-309
Charles W. Harrison,
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摘要:
An expression is derived for the mutual impedance of a symmetrical center‐driven antenna in proximity to an untuned parasitic element, when the wires are parallel, and are not displaced in length. An integral, frequently occurring in antenna problems, is evaluated graphically over the range required in the present analysis.
ISSN:0021-8979
DOI:10.1063/1.1714990
出版商:AIP
年代:1943
数据来源: AIP
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