摘要:

The shape and extent of space charge regions in semiconductor surfaces are briefly discussed. Curves describing the potential as a function of distance inside the semiconductor are obtained by numerical integration of the Poisson equation. The curves apply to all semiconductors. They show the effects of different resistivities and the increased depth of the space charge regions expected in pure III‐V compounds over those encountered in Ge and Si.

ISSN:0021-8979    

DOI:10.1063/1.1723012

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

It is shown that the reduction of a metal oxide such as nickel oxide by hydrogen gas is strongly influenced by nuclear irradiation. The initial induction period is shortened and the subsequent reduction accelerated. The effects anneal out at higher temperatures. A probable mechanism of this acceleration is suggested.

ISSN:0021-8979    

DOI:10.1063/1.1723013

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

The emf of a galvanic cell which consisted of a stressed metal electrode and an unstressed metal electrode was measured. The experimental data showed that for low torsional stresses there was a parabolic relationship between the emf and the torsional stress.It was observed that the stressed electrode was more anodic with respect to the unstressed reference electrode in agreement with the majority of the previous investigations.Experimental data of emf and torsional stresses for B & S gauge 12, 14, and 16 hard‐drawn copper wires are presented.

ISSN:0021-8979    

DOI:10.1063/1.1723014

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

The occurrence of dislocation sites along grain boundaries is shown by transmission electron microscopy. Small thin sections of aluminum for these studies were obtained by electrolytic oxidation, with subsequent dissolution of the oxide. Dislocation sites along grain fragments in cold worked aluminum have been observed which, by Cottrell's formula, indicate grain orientation differences greater than 2° of arc. This method of examination makes possible the observation and analysis of dislocations in metals where boundaries are at other than extremely low angles of crystal misorientations. Also, it has been found useful for following the movement of dislocations within grains of the material and their migration to grain boundaries.

ISSN:0021-8979    

DOI:10.1063/1.1723015

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

The dielectric relaxation spectra of a system of lithium borosilicate glasses have been investigated over the frequency range 0.01 cps to 500 kc and temperatures between 25°–350°C. The spectra of the samples exhibit well‐defined peaks in the dielectric loss factor and dispersion in the dielectric constant. The activation energies associated both with the lithium ion mean relaxation frequency and the lithium ion dc conductivity (zero frequency conductivity) are constant with temperature; their difference for each sample appears to be an indication of the distribution of activation energies of the sample. The experimental data show that an analytical function proposed by K. W. Wagner adequately describes the distribution of relaxation times associated with the lithium ion relaxation process in the glass network. The distribution originates from a spread in activation energies for low lithium concentrations and a spread in the period of vibration of the lithium ions about their equilibrium position for higher concentrations.

ISSN:0021-8979    

DOI:10.1063/1.1723016

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

By modulating a beam strongly with a high‐level signal, called the ``pump'' signal, a low‐level space charge wave of another frequency imposed on the beam can be parametrically amplified. With the pump frequency twice the signal frequency, 13‐db gain per plasma wavelength has been observed in a movable cavity experiment. Over a 10‐in. length of beam the signal has been observed to increase 41 db. When the imposed signal wave's frequency is not exactly half the pump frequency, the beam generates another wave called the ``idler'' such that &ohgr;signal+&ohgr;idler=&ohgr;pumpwith both signal and idler growing exponentially with distance along the beam. In another experiment with the pump frequency lower than the signal frequency, the signal was observed to increase by 30 db over a 9.2 in. length of beam.

ISSN:0021-8979    

DOI:10.1063/1.1723017

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

A technique of controlling the shape of detonation wave fronts in high explosives by inert wave control inserts was applied to generate discrete ultrahigh‐velocity pellets. Tests to determine the most suitable pellet shape as well as the optimum charge configuration are described, and velocities up to 7600 m/sec were realized for 0.95‐g aluminum pellets. The mechanism whereby pellets are accelerated by ``shaped'' waves is discussed, and the conclusion is reached that a simple model based upon the transmission of shock from the detonation wave to the pellet is not applicable.

ISSN:0021-8979    

DOI:10.1063/1.1723018

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

An analytical model, which is applicable to static fatigue of lime glass, has been extended to account for dynamic fatigue of the same glass. The model successfully predicts the room temperature strain rate sensitivity of the failure process in lime glass and indicates a method by which the stress concentration relationship, applicable to microscopic flaws on glass surfaces, may be obtained by experiment. Resulting experiments showed that the stress concentration relationship proposed by Inglis is valid.

ISSN:0021-8979    

DOI:10.1063/1.1723019

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

An arc cathode spot in a transverse magnetic field may move either in the Amperian (forward) direction, or in the opposite (retrograde) direction. Experiments are described which show that forward continuous motion is caused by magnetic fields at the cathode surface, as is the case with retrograde motion, and that both of these motions depend upon the material and surface condition of the cathode. Forward cathode velocity both when continuous and when moving in a stepping process is independent of arc current over a wide range.The theories so far suggested for retrograde motion do not appear to be able to account for the dependence of retrograde cathode movement on the nature of the cathode surface.

ISSN:0021-8979    

DOI:10.1063/1.1723020

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

Thermometric observations have been made of the phenomena accompanying the stabilization and the recombination of free nitrogen atoms in a solid molecular nitrogen matrix at liquid helium temperatures. Condensation from the gas phase may occur at temperatures considerably above the 4.2°K coolant temperature as the result of the normal change in heat content and the heat of atom recombination. Estimates, made from the latter effects, of the free atom concentration in the gas phase were as high as 4 atom %. Qualitative confirmation of the presence of an energetic species stabilized in the solid phase was made by detection of heat release upon warmup. From the latter effect a minimum nitrogen atom concentration in the solid of 0.03 atom % was estimated. For the conditions used the initiation of atom recombination occurs at a temperature of about 9°K. The upper limit of about 36°K for stabilization coincides with the known thermal transition in solid nitrogen. The data suggest that at least above 9°K diffusion of nitrogen atoms occurs throughout the solid matrix during deposition from the gas phase. If recombination during warmup is diffusion‐controlled, unusual dependence upon temperature is indicated.

ISSN:0021-8979    

DOI:10.1063/1.1723021

出版商:AIP    

年代:1958

数据来源: AIP