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21.
采用热力学统计理论研究了液态甲烷在高温高压下分子分解反应特点及该体系的物态方程。着重讨论了体系中CH4-H2分子间有效势对体系化学反应平衡及物态方程的影响,并根据实验Hugoniot点(pH, V)优化确定出其exp-6势函数中的参数值。该势函数的排斥部分值比理想混合条件下Lorentz-Berthelot规则给出的势函数值低约50%,预示着高压下CH4和H2之间存在着某种亲合性。用该势函数计算得到的p-T线与现有的两个实验点符合很好。还讨论了CH4-H2之间的有效作用势参数对CH4分子冲击离解度(x)的影响。 相似文献
22.
采用X光照相检测GH163合金TIG(tungsten-inert-gasarcwelding)焊结构时,在胶片上发现焊缝中心有一黑线。本文通过X光偏转实验和光学金相对其形成机制进行了研究,并提出了防治措施。 相似文献
23.
对重氢原子进入钯或钛晶体中可能引起常温核聚变的机理探讨与实验研究结果,已在文献[1]中作了报导。后来又对钛阴极材料,在使用前后进行了X射线结构分析。发现在电解过程中发生过“过热”现象的钛阴极材料的晶体结构由原来的密排六方结构转变为立方结构,而没有发生“过热”现象的钛阴极材料的晶体仍然保持电解前的密排六方结构 相似文献
24.
We prove that a properly embedded minimal annulus with one flat end, bounded in a slab by lines or circles, is a part of a Riemann's example.
25.
Coplanar Phase Shifters Based on Ferroelectric Thin Films 总被引:2,自引:0,他引:2
Chunlin Fu Fusheng Pan Hongwei Chen Shucheng Feng Wei Cai Chuanren Yang 《International Journal of Infrared and Millimeter Waves》2007,28(3):229-235
Barium strontium titanate (Ba0.6Sr0.4TiO3, short for BST) thin films were prepared by RF-magnetron sputtering. The dielectric tunability, loss tangent, remanent polarization
(2Pr) and coercive electric field (Ec) of the BST films are respectively 29.5%, 0.013, 2.29 μC/cm2 and 22.27 kV/cm at 1 kHz and 20 V. The designed coplanar waveguide (CPW) phase shifter consists of 56 same sections. It is
shown that the fabricated lines of electrodes are smooth and the widths at the tip of bottom electrodes are about 5 μm. At
the central frequency of 28 GHz and a bias voltage of 20 V, the figure of merit is approximately 13°/dB. 相似文献
26.
A hybrid algorithm for nonlinear minimax problems 总被引:1,自引:0,他引:1
In this paper, a hybrid algorithm for solving finite minimax problem is presented. In the algorithm, we combine the trust-region
methods with the line-search methods and curve-search methods. By means of this hybrid technique, the algorithm, according
to the specific situation at each iteration, can adaptively performs the trust-region step, line-search step or curve-search
step, so as to avoid possibly solving the trust-region subproblems many times, and make better use of the advantages of different
methods. Moreover, we use second-order correction step to circumvent the difficulties of the Maratos effect occurred in the
nonsmooth optimization. Under mild conditions, we prove that the new algorithm is of global convergence and locally superlinear
convergence. The preliminary experiments show that the new algorithm performs efficiently. 相似文献
27.
28.
A general monotonization method is proposed for converting a constrained programming problem with non-monotone objective function and monotone constraint functions into a monotone programming problem. An equivalent monotone programming problem with only inequality constraints is obtained via this monotonization method. Then the existing convexification and concavefication methods can be used to convert the monotone programming problem into an equivalent better-structured optimization problem. 相似文献
29.
30.
This paper is concerned with the use of distributed vibration neutralisers to control the transmission of flexural waves on a beam. Of particular interest is an array of beam-like neutralisers and a continuous plate-like neutraliser. General expressions for wave transmission and reflection metrics either side of the distributed neutralisers are derived. Based on transmission efficiency, the characteristics of multiple neutralisers are investigated in terms of the minimum transmission efficiency, the normalised bandwidth and the shape factor, allowing optimisation of their performance. Analytical results show that the band-stop property of the neutraliser array depends on various factors, including the neutraliser damping, mass, separation distance in the array and the moment arm of each neutraliser. Moreover, it is found that the particular attachment configuration of an uncoupled force-moment-type neutraliser can be used to improve their overall performance. It is also shown that in the limit of many neutralisers in the array, the performance tends to that of a continuous neutraliser. 相似文献