Some comments on the stability theory of mhd shock waves

The stability (evolutionarity) problem for a kind of MHD shock waves is discussed in this paper. That is to solve the interaction problem of MHD shock waves with (2-dimensional) oblique incident disturbances. In other words, the result of gasdynamic shocks is generalized to the case of MHD shocks. The previous conclusion of stability theory of MHD shock waves obtained from the solution of interaction problem of MHD shock wave with (one-dimensional) normal shock wave is that only fast and slow shocks are stable, and intermediate shocks are unstable. However, the results of this paper show that when the small disturbances are the Alfven waves a new stability condition which is related to the parameters in front of and behind the shock wave is derived. When the disturbances are entropy wave and fast and slow magneto acoustic waves the stability condition is related to the frequency of small disturbances. As the limiting ease, i. e. when a normal incident (reflection, refraction) is consid...更多ered, the fast and slow shocks are unstable. The results also show that the conclusion drawn by Kontorovich is invalid for the stability theory of shock waves.

波浪和风生浪流作用下的近岸海底泥沙运移模型的推广和应用

本文利用数值计算和经验公式相结合的方法，获得了在波浪和风生流和波浪共同作用下海底泥沙输移的二维模型．在此基础上，讨论了海底泥沙输移在风速、风向和泥沙粒径不同等三种情况下的变化特征；指出了经验公式对泥沙输移规律的适用范围以及风速、风向对于近岸处泥沙输移重要性．这一研究结果对近岸结构物的选址设计具有实际应用价值．

Adiabatic shear localization: occurrence, theories, and applications

中国的神光——神光Ⅱ高功率激光实验装置

惯性约束聚变（ICF）研究的长远目标，是实现可控核聚变，为人类提供理想的能源。神光Ⅱ高功率激光装置是由中国科学院、中国工程物理研究院、国家高技术863计划支持的大科学工程项目。该装置是目前我国规模最大、国际上为数不多的高性能高功率固体激光装置，是我国中近期惯性约束聚变重要实验平台。

Temperature- and salinity-dependent development of a Nordic strain of Ichthyophthirius multifiliis from rainbow trout

During the twentieth century evidence was presented which suggested the presence of various strains and races of the parasite Ichthyophthirius multifiliis Fouquet. However, ecological profiles of various parasite isolates from different climatic zones are sparse. Such stringent characterizations of parasite development at defined abiotic conditions could provide valuable criteria for the different races: profile comparison from various localities is one way to differentiate these strains. Baseline investigations were therefore performed on the associations between abiotic factors (temperature/salinity) and the development of theronts in tomocysts of I. multifiliis isolated from rainbow trout in a Danish trout farm. It was shown that tomocyst formation and theront development took place between 5 and 30degreesC. Development rates and sizes of theronts were clearly affected by temperature: theronts escaped tomocysts already after 16-27 h at 25degreesC and 30degreesC, whereas this process took 8-9 days at 5degreesC. Likewise, theront size decreased steadily from a maximum of 57.4 x 28.6 mum at 5degreesC to 28.6 x 20.0 mum at 30degreesC. This size variation was only partly associated with the number of theronts that appeared at different temperatures. The lowest number of theronts escaping from one tomocyst was indeed found at 5-7degreesC (mean 329-413). At 11.6, 17.0 and 21degreesC. the highest number of theronts appeared (mean 546-642). However, at 25 and 30degreesC, the number decreased (458 and 424, respectively). Additional studies on the salinity dependent development of the parasite (at 11.6degreesC) showed that salinities above 5 p.p.t. totally inhibited development. Even at 5 p.p.t. the developmental time significantly increased and the number of theronts produced from one tomocyst decreased.

Promoting strain relaxation of Si0.72Ge0.28 film on Si (100) substrate by inserting a low-temperature Ge islands layer in UHVCVD

A flat, fully strain-relaxed Si0.72Ge0.28 thin film was grown on Si (1 0 0) substrate with a combination of thin low-temperature (LT) Ge and LT-Si0.72Ge0.28 buffer layers by ultrahigh vacuum chemical vapor deposition. The strain relaxation ratio in the Si0.72Ge0.28 film was enhanced up to 99% with the assistance of three-dimensional Ge islands and point defects introduced in the layers, which furthermore facilitated an ultra-low threading dislocation density of 5 x 10(4) cm (2) for the top SiGe film. More interestingly, no cross-hatch pattern was observed on the SiGe surface and the surface root-mean-square roughness was less than 2 nm. The temperature for the growth of LT-Ge layer was optimized to be 300 degrees C. (C) 2008 Elsevier B.V. All rights reserved.

八种气体中28种杂质全分析技术及质量监控

于G批量导入至Hzhangdi

电子级气体N2、H2、O2、Ar、He、HCl、CO2、NH3 28种杂质分析技术及质量监控

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Uniform mems chip temperatures in the nucleate boiling heat transfer region by selecting suitable, medium boiling number range

The not only lower but also uniform MEMS chip temperatures can he reached by selecting suitable boiling number range that ensures the nucleate boiling heat transfer. In this article, boiling heat transfer experiments in 10 silicon triangular microchannels with the hydraulic diameter of 55.4 mu m were performed using acetone as the working fluid, having the inlet liquid temperatures of 24-40 degrees C, mass fluxes of 96-360 kg/m(2)s, heat fluxes of 140-420 kW/m(2), and exit vapor mass qualities of 0.28-0.70. The above data range correspond to the boiling number from 1.574 x 10(-3) to 3.219 x 10(-3) and ensure the perfect nucleate boiling heat transfer region, providing a very uniform chip temperature distribution in both streamline and transverse directions. The boiling heat transfer coefficients determined by the infrared radiator image system were found to he dependent on the heat Axes only, not dependent on the mass Axes and the vapor mass qualities covering the above data range. The high-speed flow visualization shows that the periodic flow patterns take place inside the microchannel in the time scale of milliseconds, consisting of liquid refilling stage, bubble nucleation, growth and coalescence stage, and transient liquid film evaporation stage in a full cycle. The paired or triplet bubble nucleation sites can occur in the microchannel corners anywhere along the flow direction, accounting for the nucleate boiling heat transfer mode. The periodic boiling process is similar to a series of bubble nucleation, growth, and departure followed by the liquid refilling in a single cavity for the pool boiling situation. The chip temperature difference across the whole two-phase area is found to he small in a couple of degrees, providing a better thermal management scheme for the high heat flux electronic components. Chen's [11 widely accepted correlation for macrochannels and Bao et al.'s [21 correlation obtained in a copper capillary tube with the inside diameter of 1.95 mm using R11 and HCFC123 as working fluids can predict the present experimental data with accepted accuracy. Other correlations fail to predict the correct heat transfer coefficient trends. New heat transfer correlations are also recommended.

环形聚苯乙烯稀溶液性质的研究

本工作对环形聚苯乙烯的溶液性质作了系统研究。工作中运用了各种溶液性质的研究方法如激光光散射、凝胶色谱和溶液粘度。对不同分子量(1 * 10~4 ～ 2.3 * 10~5)的窄分布环形聚苯乙烯样品在良溶剂甲苯，不良溶剂丁酮以及不同温度的环已烷中第二维利系数的测定发现，在良溶剂中环形聚苯乙烯的第二维利系数小于线形聚苯乙烯，在不良溶剂中两者第二维利系数相近，而环形聚苯乙烯在环已烷中的θ温度为30 ℃，比线形聚苯乙烯的θ温度低4.5 ℃。这些结果表明环形聚苯乙烯分子间排斥体积效应小于线形分子，而分子内排斥体积效应略大于线形分子。环形聚苯乙烯在甲苯(25 ℃)和丁酮(25 ℃)中的第二维利系数与分子量的关系分别为甲苯 A_(2r) = 1.28 * 10~(-2) (M-bar)_w~(-0.283)丁酮 A_Z(2r) = 5.06 * 10~(-3) (M-bar)_w~(-0.273)通过测定环形聚苯乙烯系列样品在θ溶剂，良溶剂和不良溶剂中的特性粘数，确定了环形聚苯乙烯在多种溶剂中的Mark-Houwink方程，在θ溶剂中的Mark-Houwink方程为[η]_r = 5.102 * 10~(-2) (M-bar)_w~(0.508) 环已烷30 ℃应用粘度结果讨论了环形聚苯乙烯的粘度扩展因子、等效球半径，均方回转半径以及穿流效应，并与线形聚苯乙烯作了比较。

In_(0.28)Ga_(0.72)As/GaAs量子点超晶格的生长

于2010-11-23批量导入