摘要:

The energy balance is discussed and a semi‐empirical equation for recovery time is derived; the discussion is based on diffusion alone without consideration of cumulative ionization and metastable states. Corroborating the theoretical considerations, measurements were made of arc drop and recovery time in thyratrons filled with mixtures of Xe with Ar, Ne, and He. The spectral emission lines in these discharges were photographed in the visible range. It was found that the arc drop remained fairly constant down to low concentrations of Xe and then increased steeply. Lines of the gas other than Xe also appeared only at low concentrations of Xe. The recovery time is a monotone declining function of the mixture of the heavy and the light components. The spectral lines are tabulated.

ISSN:0021-8979    

DOI:10.1063/1.1721318

出版商:AIP    

年代:1953

数据来源: AIP

摘要:

An attempt is made to determine the actual distribution of the pore sizes in a porous rock from the cumulative distribution of mercury injected into the rock with increasing pressure against capillary forces. The aim is to correct for those pores which could fill at a given pressure but which do not, because they are connected to the mercury source only by smaller pores. The presented correction is based on probability concepts.

ISSN:0021-8979    

DOI:10.1063/1.1721319

出版商:AIP    

年代:1953

数据来源: AIP

摘要:

Equipment for evaporation of germanium in vacuum at various measurable rates is described. The activation energy of evaporation is 3.5 ev, which is in close agreement with recent data by Searcy.

ISSN:0021-8979    

DOI:10.1063/1.1721320

出版商:AIP    

年代:1953

数据来源: AIP

摘要:

The theory of elastic wave propagation in systems where discontinuities in the physical properties occur along concentric cylindrical surfaces is developed for an impulsive ring‐shaped source. This source is mathematically similar to the point source discussed by Lamb and Pekeris. The field problem is solved for a liquid‐filled column, surrounded by an elastic solid, representing a basic model applicable to well‐logging problems.

ISSN:0021-8979    

DOI:10.1063/1.1721321

出版商:AIP    

年代:1953

数据来源: AIP

摘要:

This paper deals with the subharmonic oscillations which occur in systems with nonlinear restoring force. It is first shown that the order of the subharmonics has a close connection to the form of the nonlinear characteristics. The subharmonic oscillation of order ⅓, i.e., the oscillation whose fundamental frequency is one‐third that of the applied force, is then particularly investigated for the cases in which the nonlinear characteristics are expressed by (1) cubic and (2) quintic functions. In both cases the stability problem of the periodic solution is discussed in detail according to the stability criterion given previously by the author. The analysis reveals that in the latter case (2) the second higher‐harmonic of the subharmonic, i.e., the oscillation of order ⅔ builds up with negative damping. This is verified by experiments in which the oscillation of order ⅔ causes the collapse of the original subharmonic oscillation.

ISSN:0021-8979    

DOI:10.1063/1.1721322

出版商:AIP    

年代:1953

数据来源: AIP

摘要:

It has been the usual practice when designing a rotating Adcock antenna system to allow a spacing of one‐half wavelength between opposite dipoles at the highest intended frequency of operation. A mathematical analysis of this antenna system is presented, and it is shown that an optimum spacing for the most clearly defined nonmultiple nulls approaches a full wavelength. Useful design formulas are developed and typical response curves are presented graphically.

ISSN:0021-8979    

DOI:10.1063/1.1721323

出版商:AIP    

年代:1953

数据来源: AIP

摘要:

A new method for the study of preferred orientation in polycrystalline materials with a Geiger counter x‐ray spectrometer is described. The unique feature of the method is that a spherical diffraction specimen is employed. Sufficient data for the construction of a complete pole figure may be obtained, and the observed intensities may be plotted directly on a stereographic net without geometry or absorption corrections. The method may be used satisfactorily with the heavy metals since x‐rays are not transmitted through the specimen. A technique for accurately machining and electroetching spherical specimens is given, and the special goniometer used with the spectrometer is described. Sample data are given and their interpretation discussed. The method is compared with other recently developed techniques for the study of preferred orientation.

ISSN:0021-8979    

DOI:10.1063/1.1721324

出版商:AIP    

年代:1953

数据来源: AIP

摘要:

The expression for the driving point impedance of a generalized electric circuit as vizualized by the author is partially integrated, and the physical significance of certain terms is discussed in connection with their application to antenna problems. Upon postulating an unattenuated traveling wave as a first approximation to the current along either a terminated rhombic or Vee antenna, a formula is derived for the free space radiation impedance of each. The expressionradiation impedanceis used for that portion of the driving point impedance which may be determined from the complex power into the external fields. The resistive component of the impedance for the rhombic antenna checks with the radiation resistance as listed by Leonard Lewin in a discussion of a paper by Donald Foster, with Lewin apparently obtaining his formula by the solid angle Poynting vector method.

ISSN:0021-8979    

DOI:10.1063/1.1721325

出版商:AIP    

年代:1953

数据来源: AIP

摘要:

In the application of the Guinier‐Tennevin focusing Laue method to the study of crystal distortion, it is found that the use of a Soller slit in the incident beam produces striations in reflections from certain crystals. The diffraction geometry of a beam so modified is examined in detail, and it is shown that the striations are due to torsion of the crystal. The relation between the amount of torsion and the slope and spacing of the striations is treated quantitatively. There results a useful extension of the focusing Laue method by which not only the bending, but also the torsion, of a crystal may be measured.

ISSN:0021-8979    

DOI:10.1063/1.1721326

出版商:AIP    

年代:1953

数据来源: AIP

摘要:

The two‐dimensional problem of the Maxwellian field from a line source of current adjacent to a conducting half‐plane is treated by a transform method of solution. Expressions in the form of contour integrals are given for the current induced in the conductor and for the radiated field.

ISSN:0021-8979    

DOI:10.1063/1.1721327

出版商:AIP    

年代:1953

数据来源: AIP