摘要:

A model is proposed to explain the electron‐emission properties of metals coated with thin evaporated films of BaO. The model considers the BaO‐metal interface to be rectifying, and the interior of the BaO layer to have a large density of donor sites. Experimental data from both this laboratory and the literature, pertaining to both thermionic and photoelectric emission properties, are shown to be consistent with predictions based on the proposed model. A striking enhancement is reported in the photoemission from BaO‐coated cathodes that are either bombarded by electrons or heated. The theory developed explains the observed dependence of work function on BaO‐layer thickness, the observed independence of emission work function on the work function of the substrate metals, and the effects of nonuniform BaO deposits on electron‐emission properties.

ISSN:0021-8979    

DOI:10.1063/1.1710112

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

The dc potential solutions which have zero slope at the emitter are calculated and examined for the low‐pressure cesium diode. It is assumed that ions and electrons are emitted thermionically at the emitter with a given ratio of ion‐to‐electron saturation currents and a positive dc potential is applied to the collector. Furthermore, the potential is nowhere negative in the diode and electron saturation current flows through it. This assumption limits the range of &agr;'s to 0<&agr;<1, where &agr; is the ratio of ion‐to‐electron saturation currents times the square root of the ratio of their masses. It was found by Auer and Hurwitz that monotonically increasing potential solutions can exist only for the range of &agr;'s, 0<&agr;<0.405. In the range 0.35<&agr;<0.405 we found large amplitude oscillations in the diode by computer simulation methods. The static solutions for &agr;<0.35 were found stable. For 1>&agr;>0.405 the static potential solutions have a long zero slope region within the diode or become periodic in space. All these solutions were found unstable and nonexistent in the diode that operates under time‐varying conditions just as predicted by Auer and Hurwitz.

ISSN:0021-8979    

DOI:10.1063/1.1710113

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

The non‐self‐similar diffusion of energy from an enclosure is investigated for plane parallel geometry for the case where the transport of energy is purely radiative. The energy released instantaneously in the cavity is partitioned in arbitrary proportions between radiant energy and internal energy of matter. The mean free path of radiation in the walls bounding the enclosure varies as the cube of the temperature, but the material within the enclosure is assumed to be transparent to radiation.Solutions for the non‐self‐similar radiative diffusion of radiation from the cavity are expressed in parametric form and numerical results are displayed graphically. In addition, series solutions are given which apply in the limit of short and long times after the initial release of energy in the cavity.

ISSN:0021-8979    

DOI:10.1063/1.1710114

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

The high‐frequency conductivity of a partially ionized, homogeneous plasma near equilibrium is calculated. Interactions between charged particles are treated by BBGKY methods, and interactions between neutral and charged particles are treated by a Boltzmann collision integral. Solution of the second hierarchy equation is facilitated by a modification of an operator technique developed by Dupree. Numerical results in the limit of infinite ion mass are studied in terms of an effective charged‐particle‐charged‐particle collision frequency which is found to depend on the neutral‐particle density and the external‐field frequency.

ISSN:0021-8979    

DOI:10.1063/1.1710115

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

This paper describes a single‐particle collisional theory of the two‐ and three‐pulse echo trains that are stimulated when a magnetoplasma is subjected to repeated pulses at the cyclotron frequency, and presents results of a series of experiments supporting the applicability of the theory. A major prediction of the analysis that has been confirmed experimentally is that, when dissimilar pulses are applied, an arbitrary pulse shape can be stored and recalled. The possible applications of echo phenomena to the study of collision processes, and in memory devices, are discussed briefly.

ISSN:0021-8979    

DOI:10.1063/1.1710116

出版商:AIP    

年代:1967

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1710118

出版商:AIP    

年代:1967

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1710119

出版商:AIP    

年代:1967

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1710121

出版商:AIP    

年代:1967

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1710122

出版商:AIP    

年代:1967

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1710123

出版商:AIP    

年代:1967

数据来源: AIP