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131.
M.A. Margulis 《Ultrasonics》1985,23(4):157-169
Contemporary ideas on the nature of cavitation are reviewed in this paper. The general theories of sonoluminescence and sonochemical reactions, the origin, stability and splitting of cavitation bubbles, the dynamics of cavitation field evolution, the peculiarities of cavitation effects at low intensity and low-frequency acoustic oscillations, the sonoluminescence quenching effect and some questions on the energetics of cavitation fields are discussed. The electrical theory of the splitting of cavitation bubbles may, as shown in the paper, become an alternative to the thermal theories of cavitation in the future. 相似文献
132.
Ramesh Chander Kapoor 《Pramana》1976,7(5):334-343
Gravitational recoil of a gigantic black hole (M∼108–9 M⊙) formed in the nonspherical collapse of the nuclear part of a typical galaxy can take place with an appreciable speed as
a consequence of the anisotropic emission of gravitational radiation. Accretion of gaseous matter during its flight through
the galaxy results in the formation of a glowing shock front. The accompanying stellar captures can lead to the formation
of an accretion disk-star system about the hole. Consequently, the hole can become “luminous” enough to be observable after
it emerges out of the galaxy. The phenomenon seems to have an importance in relation to the observations of quasar-galaxy
association in a number of cases. 相似文献
133.
Stable arrays of cylindrical bubbles with diameters 3 and 4 μm were produced by trapping air in the pores of hydrophobic Nuclepore filters. These bubble arrays were irradiated by beams of cw and pulsed ultrasound at carrier frequencies near the resonance frequencies of the trapped bubbles. By examining the frequency spectrum of the field scattered by the arrays it was found that the bubbles may oscillate as non-linear stable cavities of long duration. Using short pulses, the bubbles remain stable up to excitation pressure amplitudes of several bars. Mechanisms for the eventual growth and decay of the bubbles are discussed in light of the observations. 相似文献
134.
J. W. F. Dorleijn W. F. Druyvesteyn 《Applied Physics A: Materials Science & Processing》1973,1(3):167-169
In the bubble collapse technique the domain wall mobility is evaluated by measuring the shortest time for which a magnetic
bubble collapses. The way in which this evaluation should be carried out is discussed. 相似文献
135.
136.
137.
Effects of SiNx on two-dimensional electron gas and current collapse of A1GaN/GaN high electron mobility transistors 下载免费PDF全文
SiNx is commonly used as a passivation material for AlGaN/GaN high electron mobility transistors (HEMTs). In this paper, the effects of SiN x passivation film on both two-dimensional electron gas characteristics and current collapse of AlGaN/GaN HEMTs are investigated. The SiNx films are deposited by high- and low-frequency plasma-enhanced chemical vapour deposition, and they display different strains on the AlGaN/GaN heterostructure, which can explain the experiment results. 相似文献
138.
分析了含气量对粘性液体中球形单空泡脉动特性的影响。研究结果表明:随着泡内初始含气量的增加,空泡达到最大泡半径的时间延长;空泡膨胀的最大泡半径、收缩的最小泡半径和脉动周期均随初始含气量的增加而增加;同时,空泡膨胀和溃灭时泡壁的运动速度均随空泡初始含气量的变化而变化。无论含气量如何,在空泡收缩到最小泡半径附近,泡壁运动速度(收缩或膨胀)要明显快于其在最大泡半径附近;此外,受液体粘性影响,空泡膨胀和收缩过程明显变缓。 相似文献
139.
Effects of SiNx on two-dimensional electron gas and current collapse of AlGaN/GaN high electron mobility transistors 下载免费PDF全文
SiN_x is commonly used as a passivation material for
AlGaN/GaN high electron mobility transistors (HEMTs). In this paper,
the effects of SiN_x passivation film on both two-dimensional
electron gas characteristics and current collapse of AlGaN/GaN HEMTs
are investigated. The SiN_x films are deposited by high- and
low-frequency plasma-enhanced chemical vapour deposition, and they
display different strains on the AlGaN/GaN heterostructure, which
can explain the experiment results. 相似文献
140.
Electric-stress reliability and current collapse of different thickness SiNx passivated AlGaN/GaN high electron mobility transistors 下载免费PDF全文
This paper investigates the impact of electrical degradation and current collapse on different thickness SiNx passivated AlGaN/GaN high electron mobility transistors.It finds that higher thickness SiNx passivation can significantly improve the high-electric-field reliability of a device.The degradation mechanism of the SiNx passivation layer under ON-state stress has also been discussed in detail.Under the ON-state stress,the strong electric-field led to degradation of SiNx passivation located in the gate-drain region.As the thickness of SiNx passivation increases,the density of the surface state will be increased to some extent.Meanwhile,it is found that the high NH 3 flow in the plasma enhanced chemical vapour deposition process could reduce the surface state and suppress the current collapse. 相似文献