摘要:

V3Si crystals have been grown by electron‐beam melting using a procedure simpler than previous methods. The resultant crystals are of high quality with a low oxygen content and with a superconducting‐transition temperature of 16.9 K, a resistivity ratio of 40, and a martensitic transformation at 21.7 K.

ISSN:0021-8979    

DOI:10.1063/1.325104

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

60‐Hz losses of Nb3Sn were found to be considerably reduced by anodizing. Anodizing followed by etching in dilute HF was also studied and found to be less effective because of increased surface roughness and hydrogen inclusion after prolonged contact with the acid. The increase of ac losses from contact with the bronze at the surface of Nb3Sn made by solid‐state diffusion was investigated. Both a surface effect (proximity?) and thermal stress were found to contribute to the increased losses.

ISSN:0021-8979    

DOI:10.1063/1.325105

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

The electric current flow upon illumination of the TiO2electrode in ann‐TiO2/KOH/Pt photolytic cell without auxiliary external voltage is related to the production of hydrogen or the reaction with dissolved oxygen at the Pt electrode depending on the electrolyte and the atmosphere above the electrolyte. Since hydrogen is produced with a pressure of much less than atmospheric pressure, no bubbles appear at the Pt electrode. The pressure and the production rate of the generated hydrogen are determined by the depth of immersion of the Pt electrode. The increase of both pressure and production rate of hydrogen upon application of an auxiliary voltage, as well as the energy‐level diagram of the photolytic cell, are discussed on the basis of the experiments carried out without auxiliary voltage.

ISSN:0021-8979    

DOI:10.1063/1.325080

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

We performed a direct measurement of dielectrophoretic forces on particles immersed in a fluid, in a given electrode configuration which permits particle levitation. We show that the force on several neighboring particles is much larger than that acting on an isolated particle in the same field distribution. We discuss the consequences of the measurements on the use of dielectrophoresis for material separation.

ISSN:0021-8979    

DOI:10.1063/1.325106

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

An inductively driven rail‐gun macroparticle accelerator has been built in which velocities of 5.9 km/s have been obtained using an arc as the driving armature. Simple theory is shown to be adequate for predicting rail‐gun performance up to that velocity and for designing rail guns for launching large masses.

ISSN:0021-8979    

DOI:10.1063/1.325107

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

A closed‐form approximation to the transient behavior of high‐radiance double‐heterojunction LED’s is derived based on the assumption of current‐independent space‐charge capacitance. The resulting expression for the rise time is found to agree with experiment to a useful degree of approximation.

ISSN:0021-8979    

DOI:10.1063/1.325108

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

A conceptual design is presented for a fault‐current limiter for the electrical power utilities which utilizes a superconducting element to commutate the fault current into a shunt resistor. The technical feasibility of the concept is supported by a computer simulation of the switching. A three‐phase 145‐kV 2‐kA electrical system is considered in detail for ease of comparison with other fault‐current limiters. Finally, the important advantages of such a fault‐current limiter are pointed out, and the areas of additional research for the immediate future are indicated.

ISSN:0021-8979    

DOI:10.1063/1.325061

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Single active‐layer visible‐spectrum In1−xGaxP1−zAszheterostructure lasers are described that exhibit quantum size effects (QSE) in photoluminescence and by means of diode injection (&lgr;<6300 A˚). Liquid‐phase epitaxial (LPE) quaternary layers as thin as ∼300 A˚ have been realized. It is demonstrated that single thin‐layer recombination wells (Lz<1000 A˚) are very effective in the capture and recombination of carriers, even if injection occurs at some distance (a<1 &mgr;m) from the thin layer. On the other hand, optical confinement and absorption are weak in diodes with single active layers thin enough to exhibit QSE. This behavior indicates that the type of thin‐active‐layer diodes described here are not optimum as lasers, but may lead to improved light emitters.

ISSN:0021-8979    

DOI:10.1063/1.325062

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

CO and CO2laser activity has been produced by acetone decomposition in a glow discharge. A gas mixture of He‐CH3COCH3‐N2was used. An oxidant was not introduced. Molecular decomposition allows a nonexplicitly introduced molecule to be involved in the laser process.

ISSN:0021-8979    

DOI:10.1063/1.325063

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

One‐port SAW resonators fabricated on ST‐quartz with recessed electrode transducers and grooved reflector have been found to yield excellent device response characteristics. This configuration is superior to all others tested and is usable over a wide frequency range. The device structure and experimental data are presented. Also, an accurate and easy‐to‐use calculation scheme is presented to derive the resonance equivalent circuit parameters from experimental data.

ISSN:0021-8979    

DOI:10.1063/1.325064

出版商:AIP    

年代:1978

数据来源: AIP