摘要:

The Schottky theory of the positive column is applied to the inductive type of a high frequency discharge for cases where the electron collision frequency &ngr;cis large compared to the field frequency &ohgr;. Simultaneous solutions of the equations for the induced field and for the electron balance are obtained under the following assumptions: (1) Mobilities of electrons and ions in the discharge volume are constant; (2) the distributions of ionization rate and diffusion coefficient across the discharge tube are determined by the absolute value of the induced electric field at the inner tube radius |ER| and by its gradient at the same position; (3) the distribution ofEcan be obtained on the basis of an equivalent uniform conductivity &sgr;¯ which yields the same impedance for the discharge as the actual &sgr; distribution. The characteristic equation relating |ER| to tube radiusRcontains (compared to the positive column) an extra term which takes into account the nonuniformity of |E|. This term is expressed as a function of the parameter &rgr;R≡2R/&dgr;, where &dgr; is the skin depth. Solving forRwith assumed values of |ER| and &rgr;Rthus yields &dgr; and by the known value of &ohgr; also &sgr;¯. From the impedance relationship one then determines the value of the magnetic fieldHRthat must be applied to produce particular values of &sgr;¯ and |ER| with given &ohgr; andR. The distribution of electron densitynis obtained in relation to the undetermined value at the tube axisn0. On the basis of constant electron mobility a relationship between &sgr;¯ andn0is obtained from the impedance equivalence which allows one to calculate absolute distributions of &sgr; andn. These distributions are compatible with the |E| distribution for cases where &rgr;R≤1.4. The method is illustrated by examples for hydrogen, where empirical data for &ngr;c, electron energy, ionization, and diffusion rates are used. The results are generalized in the way common for glow discharges by introduction of gas pressurepas similarity parameter. They indicate that the maximum obtainable electron density depends primarily upon the product &ohgr;HR, only moderately uponpand not uponR.

ISSN:0021-8979    

DOI:10.1063/1.1702549

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

Calculations of the variation of cathode‐fall voltage, the cathode‐fall distance, and the Aston dark space with current density have been made for the rare gases and a few molecular gases on an electronic computer. The calculations were based upon Townsend's ionization equations, but included the field distortion due to space charge. New analyses of the field variation of Townsend's first ionization coefficient and ion mobilities are presented. The length of the dark space has been obtained from the calculated distribution of light output across the gap and agrees with the cathode‐fall distance calculated from the field distribution. Comparisons of the calculated cathode‐fall characteristics with published experimental results indicate the probable validity of the model used for the calculations.

ISSN:0021-8979    

DOI:10.1063/1.1702550

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

The formation of discrete phase GaP by diffusion of phosphorus into GaAs at pressures of 10 to 30 atm and temperatures of 800° to 900°C is described. X‐ray data identifying GaP are given. A mechanism is postulated for the step‐like concentration gradients observed. Striae supporting this hypothesis were observed and are illustrated. Epitaxial growth as a factor is considered but not believed a significant factor based on microscopy and experimental environment.

ISSN:0021-8979    

DOI:10.1063/1.1702551

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

Crystalline slip has been observed in singly and doubly oriented nylon 66 and 610 by deformation of bristles in compression parallel to their orientation direction to form kink bands. The angles of the bands correspond to two and three (010) planes acting in unison as lamella in the kinking process. Slip was also manifested along a unique crystallographic plane (010) and a unique crystallographic direction ([1,3,14] and [1,3,18] in nylon 66 and 610) during fracture experiments on doubly oriented bristles. To account for this behavior a model of the structure of these oriented polymers is proposed in which the material is considered essentially completely crystalline with many vacancies and dislocations within the lattice. The dislocations and their motions which account for the observed deformations are illustrated. The difference between observed values of density and the theoretical density of nylon 66 is attributed to vacancies. The so‐called amorphous background in x‐ray diffraction patterns of these nylons is attributed to the vacancies and dislocations in the crystal structure.

ISSN:0021-8979    

DOI:10.1063/1.1702552

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

In a negative point‐to‐plane corona discharge in air, mutual interactions are observed between the electrode and the discharge when the anode is a film composed of zinc oxide incorporated in a resin binder. The current carried by the corona discharge increases by more than fivefold as the zinc oxide becomes negatively charged. When the electrostatic charge on the zinc oxide surface is dissipated by light the current falls to the value which is observed when a metal conductor replaces the zinc oxide resin film electrode in an identical geometry.Another feature of the discharge interaction is that the zinc oxide resin films are able to accept and retain over 109electronic charges per square centimeter of excess negative electrostatic charge despite the fact that the bulk conductivity of the films measured electrodynamically either before or after corona charging is often greater than 10−11&OHgr;−1cm−1. Selected single crystals of zinc oxide have also been observed to accept and retain electrostatic charge for several seconds after exposure to the negative corona discharge, while concurrent measurements show that the conductivity of the crystals remains unchanged at 10−2&OHgr;−1cm−1throughout the experimental treatment. In both cases the charge can be dissipated by less than 1014photons/cm2of actinic light. It was thus possible to make Xerographic prints on single zinc oxide crystals. No effects comparable to these are observed with a positive corona discharge.The paper is primarily experimental in scope. Support is introduced for the hypothesis that the effect of negative ions of the corona discharge on the zinc oxide resin film surface is the creation of small isolated charged regions, presumably the result of the ``blocking contact'' made with the zinc oxide surface by individual negative ions from the discharge. These regions behave as islands of high resistivity which can accept and retain electrostatic charge even when immersed in a relatively conducting sea of unaltered film material. The anomalous, or unexpectedly high, corona current is then attributed to an increase in conductivity of the corona gap resulting from additional ionization of the air near the charged zinc oxide resin film surface. This ionization is caused by localized high potential gradients in the vicinity of excess negative charges isolated on these islands, and the dissipation of these charges by light thus produces the observed photosensitive decrease in corona current. A comparison is made between the resistive island model and the model which constrains the pigment resin film to behave as a homogeneous insulator after electrostatic charging.

ISSN:0021-8979    

DOI:10.1063/1.1702553

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

Dilute solid solutions of the system NaCl‐NaBr are considered. The displacements of the nearest, next‐nearest, and third‐nearest neighbors are dealt with microscopically and the rest of the medium is regarded as a continuous elastic medium. Heats of solution and changes in lattice constants are calculated and compared with experiment. Because of the distortion of the crystal around the impurity, appreciable field‐gradients appear at the nuclei in the neighborhood of the impurity. These field gradients are calculated and compared with some available experimental results obtained from nuclear magnetic resonance studies of these solid solutions.

ISSN:0021-8979    

DOI:10.1063/1.1702554

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

Electron diffraction transmission patterns of a decomposing ferromagnetic supersaturated gold‐nickel alloy show a Lorentz shift of the diffraction lines, which passes through a maximum for a certain decomposition state. It is probable that the maximum in the shift is determined by a maximum in the coercive force of the decomposing alloy.

ISSN:0021-8979    

DOI:10.1063/1.1702555

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

Second‐order instability ofz‐directed spin waves is investigated for the case of thin disks, assuming that the precession angle is very large. It is found that for large precession angles, the buildup rate of the spin‐wave population is proportional to the transverse magnetic moment and the square root of the transverse demagnetizing factor.

ISSN:0021-8979    

DOI:10.1063/1.1702556

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

It is shown that the inhomogeneous demagnetizing field occurring in uniformly magnetized, nonellipsoidal samples can be described by a generalized demagnetizing factor. The demagnetizing factor is a tensor and, in general, is different in different parts of the sample. The diagonal sum of this tensor field is unity at all points inside the sample and zero at all points outside the sample.

ISSN:0021-8979    

DOI:10.1063/1.1702557

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

A functional relationship between dielectric constant and voltage for a ferroelectric in the paraelectric state is derived, and Fourier capacitance coefficients for different applied voltage functions are computed. It is shown that because the loss tangent of a ferroelectric in the paraelectric state is proportional to frequency, it can be represented in the same way as a varactor; i.e., as a series resistance and capacitance. It is concluded that since the power‐handling capability of single‐crystalline ferroelectric is virtually unlimited, and since in many cases it has lower loss than a varactor diode, it will soon find wide application in parametric device design.

ISSN:0021-8979    

DOI:10.1063/1.1702558

出版商:AIP    

年代:1962

数据来源: AIP