摘要:

A new current probing method for measuring the current level in superconducting integrated circuits is proposed. In this method, a SQUID (superconductive quantum interference device) is used to pickup unknown superconductive current and a negative feedback loop is used to automatically compensate the unknown current. We have experimentally obtained a resolution of less than 2 &mgr;A and a high accuracy of better than 1%.

ISSN:0021-8979    

DOI:10.1063/1.335289

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

In order to describe exactly the renewal epochs of nonsimple Markov processes, a new experimental method has been developed which allows one to draw out of the sequence data which can be directly compared with exact formulas. The analyzed process has been obtained by superimposing an ordinary Poisson distribution with periodic signals when the whole train is processed by a device introducing a finite width (dead time) of nonextended type. Excellent agreement with the theoretical predictions has been found.

ISSN:0021-8979    

DOI:10.1063/1.335290

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

The variation of the yield strength with shock pressure of Manganin foil gauges can be determined by analyzing their dynamic calibration curve. The analysis is based on the assumption that the material behaves as an elastoplastic work‐hardening solid and on the general expression for the resistance change of Manganin which we derived in previous works. It is found that the strength increases by a factor of about 3.5 for shock stresses in the range of 0–160 kbar.

ISSN:0021-8979    

DOI:10.1063/1.335291

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Rigid wall impact experiments were conducted on alumina tiles, instrumented with in‐material Manganin gauges, in order to determine the magnitude of the dynamic yield strength of these ceramics. We found that the amplitude of the wave is very near the static yield strength. Thus, we conclude that these materials are not rate sensitive and that their increased strength in planar impact experiments is due to their pressure dependence rather than rate effects.

ISSN:0021-8979    

DOI:10.1063/1.335292

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

New results which probe the nature of a defect mechanism responsible for pinning the Fermi energy within the band gap on the (110) surfaces of the 3‐5 compounds are presented. From these results it is concluded that to first order the Fermi energy pinning position is independent of the fundamental difference between the Sb‐GaAs chemical bond and the column 3 metal‐GaAs bond. Furthermore, based on the defect mechanism for the Schottky barrier formation proposed by Spicer and Lindau, the present data can be most easily understood if the defect is more complex than a single surface lattice vacancy. Previously, investigations of column 3 metals on bothn‐ andp‐type GaAs, by photoemission electron spectroscopy, revealed a systematic difference in surface Fermi energy stabilization in the gap, withp‐type samples pinning 0.25 eV belown‐type samples. In the present work, it is shown that antimony, a column 5 element, yields essentially the same Schottky barrier height as the column 3 metals when adsorbed on GaAs (110). A strong similarity in the barrier height is also noted when Sb adsorption is compared to Ga adsorption on GaSb (110). The observed tendency forn‐type GaSb to pin closer to the valence‐band maximum than GaAs is consistent both with the Spicer/Lindau defect mechanism and with the ‘‘anion rule’’ of McCaldin, McGill, and Mead. These results are important for the theory of Schottky barrier formation and for Schottky barrier device fabrication.

ISSN:0021-8979    

DOI:10.1063/1.335293

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Beryllium (Be) thin films with superconducting transition temperature (Tc’s) up to about 6 K can be grown on room‐temperature substrates using ion‐beam sputtering. In contrast to the evaporation‐deposited Be grown on a liquid‐helium‐cooled substrate, which is also a superconductor, the ion‐beam‐sputtered Be films show such high thermal stability that theTc’s exhibit no change by room‐temperature annealing for three months.

ISSN:0021-8979    

DOI:10.1063/1.335294

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

The pressure deriviatives of the bulk, shear and Young’s moduli, and of Poisson’s ratio of a number of polycrystalline metals have been calculated using Hill’s approximation. The pressure derivatives of the second‐order elastic constants of the corresponding single‐crystal hexagonal metals have been used for this purpose.

ISSN:0021-8979    

DOI:10.1063/1.335295

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

The dispersion characteristics of the surface polaritons in the neighborhood of the band gap occurring near the edge of the first Brillouin zone are deduced and used in determining the reflectivity of the surface polaritons incident normally on a small amplitude grating of finite length.

ISSN:0021-8979    

DOI:10.1063/1.335296

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

A simple method is proposed to analyze the current waveform of a pulsed plasma discharge from which the voltage waveform and hence the temporal evolution of the plasma inductance can be deduced. As an example, the application of the method to a typical plasma focus discharge is illustrated.

ISSN:0021-8979    

DOI:10.1063/1.335244

出版商:AIP    

年代:1985

数据来源: AIP