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991.
992.
Flow, temperature, and electromagnetic (EM) fields in a radio-frequency thermal plasma torch designed for the preparation of superconducting powders or films have been analysed by using a new two-dimensional modeling approach with the electric field intensity as the fundamental EM field variable. The insertion of a stainless steel injection tube into the torch leads to large induction currents in this tube. Although such large induction currents cause pronounced changes of the EM fields near the injection tube, flow and temperature fields are little affected. There exists only one large toroidal vortex in the upper part of the present torch, while the maximum temperature appears at an off-axis location within the coil region. 相似文献
993.
This contribution discusses the phenomena of retrograde condensation of one or two liquids. It w1 be shown that both phenomena can be well understood. Also the relation of retrograde condensation of one liquid phase with the condensation behavior of natural gas will be discussed. Similarly that of two liquid phases with multiple phase behavior occurring in low temperature reservoir fluids will be pointed out. 相似文献
994.
S. Chen H. Büttner 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(1):15-18
We generalize the Shastry-Sutherland model to three dimensions. By representing the model as a sum of the semidefinite positive
projection operators, we exactly prove that the model has exact dimer ground state. Several schemes for constructing the three-dimensional
Shastry-Sutherland model are proposed.
Received 20 February 2002 / Received in final form 27 May 2002 Published online 17 September 2002 相似文献
995.
1989年发表的Bager第五图,包含关于三角形元素的35个二次规范画数之间的51个不等式通过细致的分析,本文给出了其中遗漏的12个基本不等式 相似文献
996.
997.
B. Griepink E. A. Maier P. Quevauviller H. Muntau 《Fresenius' Journal of Analytical Chemistry》1991,339(9):599-603
Summary The Community Bureau of Reference (BCR) has undertaken the production of a wide range of certified reference materials (CRMs) for the improvement of accuracy and measurement harmony in various areas of concern at European Community level. This paper provides an overview of the sectors of the BCR-programme in the field of environment i.e. for water systems (water, sediment, biota), soil analysis (soil, fertiliser, waste), plant analysis (aquatic and terrestrial plants), analysis related to animals (e.g. muscle or liver) or man (e.g. industry and food). 相似文献
998.
关于独立同分布随机变量部分和的增量有多小问题,目前已有了著名的结果.本文通过与独立同分布情形时完全不同的途径,讨论了独立不同分布情形时相应的问题.在矩母函数存在的条件下,获得了与同分布情形相近的结论. 相似文献
999.
曙光一号自由电子激光器的理论计算 总被引:1,自引:0,他引:1
系统总结曙光一号自由电子激光器理论计算的主要结果:包括曙光一号装置主要参数的选取和理解;磁场失谐曲线的计算;常参数摇摆器和变参数摇摆器的主要结果;高阶波导模的贡献;电子束参数扰动对激光性能的影响;空间电荷效应等。计算结果表明,常参数摇摆器激光输出功率可达80MW,效率约50%;变参数摇摆器激光输出功率可达250MW左右,效率约16%。 相似文献
1000.
Summary Global average temperatures from 1860 to 1989 were analysed with a simple fitting procedure. The temperature records can be
fitted with a rising exponential up to 1946 and with the same exponential minus an increasing cooling action from 1946 to
1989. It is shown that the results are compatible with the hypothesis of an albedo increase caused by SO2 emissions. This hypothesis gives satisfactory explanations of the temperature drop in the years 1940–1970, of the different
warming of the northern and southern hemispheres and of the slower warming observed over North America. The results give an
indication that the greenhouse warming in the next years could be faster than predicted until now.
Due to the relevance of its scientific content, this paper has been given priority by the Journal Direction. 相似文献