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991.
G.C. Osborne V.L. Kantsyrev A.A. Esaulov A.S. Safronova M.E. Weller I. Shrestha K.M. Williamson V.V. Shlyaptseva 《High Energy Density Physics》2013,9(4):653-660
An exploration of the implosion properties and X-ray radiation pulses from tungsten-based planar wire array Z-pinch experiments is presented, with an emphasis on loads mixed with aluminum. These experiments were carried out on Zebra, the 1.0 MA pulse power generator at the Nevada Terawatt Facility. A suite of diagnostics was used to study these plasmas, including X-ray and EUV Si diodes, optical imaging, laser shadowgraphy, and time-gated and time-integrated X-ray pinhole imagers and spectrometers. Specifically, loads with relatively large inter-wire gaps where tungsten is placed in the center of a planar configuration composed primarily of aluminum showed unusual characteristics. These loads are shown to generate a “bubbling” effect in which plasma from the ablation of outer aluminum wires is temporarily hindered from converging at the center of the array where the tungsten wire is located. Reproduction of these experiments with variations to load geometry, materials, and mass distribution are also presented and discussed in an attempt to better understand the phenomenon. In addition, a theoretical model has also been applied to better understand the dynamics of the implosions of these loads. Applications of this effect to radiation pulse shaping, particularly with multi-planar arrays, are also discussed. 相似文献
992.
平面功率器件由于终端pp结的曲率效应,其高压阻断能力受到限制,为了提高高压阻断能力,本文研究了金属场限环的工作机理,进行了金属场限环结构参数的设计,阐述了其制造工艺和实验结果;并和扩散场限环进行了比较,证实了金属场限环是一种工艺简单、对工艺要求低的高压终端技术。 相似文献
993.
D. Steup A. Simon M. Shaalan A. Grüb C. I. Lin 《International Journal of Infrared and Millimeter Waves》1996,17(5):843-856
The design of a planar quasioptical doubler configuration with an output frequency of 290 GHz is presented. Frequency conversion is realized with a monolithic Schottky — varactor array. Coupling of electromagnetic energy from beam waveguide to chip and vice versa is carried out with integrated antenna arrays. Electromagnetic field calculations describe coupling effects between the single array elements. RF—measurements of multiplier performance are also presented. 相似文献
994.
PENGYingcai 《半导体光子学与技术》1996,2(3):168-174
The investigation on optical properties of Si1-xGex/Si strained layer structures has been carried out actively in recent years.The photoluminescence has be-come a brisker subject in the studies of its various optical properties.A research develop-ment to photoluminescence properties of some new Si1-xGex/Si strained layer struc-tures is introduced. 相似文献
995.
近年来,在光致变色材料研究领域中,人们的注意力从无机材料转移到有机材料。O-杂环俘精酸酐衍生物就是其中一类,但N-杂环俘精酸酐还没有引起人们注意。N-杂环俘精酸酐也能象O-杂环俘精酸酐一样在紫外光照射下环合成双氢吲哚的衍生物,N的给电子能力比O强,因此其双氢吲哚衍生物的吸收波长会出现红移。O-杂环俘精酸酐存 相似文献
996.
J. P. Abjean 《Chromatographia》1993,36(1):359-361
Summary Planar chromatography (PC) is of interest for veterinary drug screening. An example is given of the use of a PC screening method followed by a high performance liquid chromatographic (HPLC) method for confirmation of positives. The results for 300 samples were obtained in 14 days whereas the HPLC analysis alone would have required 50 days work. The future of PC in veterinary drug residue analysis as a screening method and also as confirmatory (quantitative) method is discussed. 相似文献
997.
多层"台阶"近似方法是将平板波导中折射率随厚度变化的曲线近似地用N层台阶形的折线来代替,使每一个小区域内折射率成为常数,由此得到电磁场分布和传播常数.本文从理论上给出了层数N与计算精度之间的关系.推导出在分割成N层和2N层两种近似下的计算值精度的改进.本文结果适用于任何渐变折射率平板光波导. 相似文献
998.
Owen J. Curnow Glen M. Fern Michelle L. Hamilton Elizabeth M. Jenkins 《Journal of organometallic chemistry》2004,689(11):1897-1910
Syntheses of the phosphinoindenes 1-(diphenylphosphino)-3-methylindene (1b), 3-(diphenylphosphino)-2-methylindene (1c), 1-(diphenylphosphino)-2,3-dimethylindene (1d), 4,7-dimethyl-3-(diphenylphosphino)indene (1e), 1-(diphenylphosphino)-3,4,7-trimethylindene (1f) and 3-(diisopropylphosphino)indene (1i) were carried out by treatment of the appropriate indenide with the appropriate chlorophosphine. The silylphosphinoindene 3-(diphenylphosphino)-1-(trimethylsilyl)indene (1h) was prepared by treatment of the indenide of 3-(diphenylphosphino)indene (1a) with trimethylsilylchloride. These indenes, in addition to 1a, were then used, after deprotonation with BuLi, to prepare the corresponding indenyl ferrocenes, 2a-2e, 2h and 2i, by treatment with ferrous chloride in a 2:1 ratio. These compounds were characterized by 1H, 13C, and 31P NMR spectroscopy, as well as by mass spectrometry, except for the highly-sensitive diisopropylphosphine 2i that could only be characterized by 31P NMR spectroscopy. All of these ferrocene complexes are bisplanar chiral systems that can potentially form rac and meso isomers. In all cases both isomers were observed but for 2b and 2h only one could be isolated. The rac isomers of complexes 2a, 2b, 2d, and 2e, as well as the meso isomer of 2e, were studied by X-ray crystallography. Only complexes 2a and 2i were observed to undergo rac/meso isomerization processes at ambient temperature in THF solvent. We were unable to prepare the sterically congested hexamethylferrocene 2f. Generally, it was found that increasing substitution on the indenyl ring increases the reactivity and sensitivity of the ferrocene. 相似文献
999.
1000.
The influence of impurities on the basal plane stacking fault energy in GaN is investigated using density functional theory. It is found that silicon, indium, magnesium and carbon impurities each reduce the stacking fault energy by introducing changes to the bonding properties of the material. These bonding properties are analysed in terms of Mulliken charges and bond populations. It is found that the reduction in stacking fault energy correlates both with a reduction in the average anion charge and with an increase in the overlap population. 相似文献