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181.
通过对Cholesky分解法求解线性方程组的分析,建立Cholesky分解法三角化对称正定阵的图模型,并基于该模型及Mesh结构P/G网络的自身特点,提出一个P/G网快速分析算法.实验证明,该算法能大大降低Mesh结构P/G网络的分析运算时间和内存占用. 相似文献
182.
PH值对化学沉积制备CdS薄膜性质的影响 总被引:3,自引:1,他引:2
实验研究了pH值对化学沉积制备CdS薄膜性质的影响。表明:在柠檬酸钠作为络合剂的体系中随着溶液中氨水浓度的提高CdS薄膜会发生相变,从立方相变为六方相,即当氨水浓度为0.31M时,得到立方相的CdS薄膜;而当氨水的浓度大于0.51M时,得到六方相的CdS薄膜。氨水浓度的提高也使得CdS薄膜的形貌有了很大的改善,且制备得到的CdS薄膜从富CA变为富S,但是薄膜仍是n型。氨水浓度对CdS薄膜的光学性质也有很大的影响,随着氨水浓度的提高所得到的CdS薄膜的禁带宽度增大。 相似文献
183.
BaXO4 (X = Mo, W) nanobelts and a variety of hierarchical superstructures assembled from the nanobelts have been synthesized in a catanionic reverse‐micelle system. The effects of various factors, such as the mixing ratio (r) between the anionic and cationic surfactants, the temperature, and the presence of polymeric additives, on the formation of the nanobelts and their hierarchical assembly have been examined in detail. In particular, r has been shown to be powerful in modulating the formation and assembly of the BaMoO4 and BaWO4 nanobelts. Architectural control of the penniform nanobelt superstructures has been readily achieved by changing the experimental parameters. A plausible two‐stage growth mechanism has been proposed for the formation of penniform BaXO4 nanobelt superstructures in catanionic reverse micelles. 相似文献
184.
A bibliometric study of China’s semiconductor literature compared with other major asian countries 总被引:1,自引:0,他引:1
In this paper we compare the scientific research in the semiconductor-related field in China with some other major nations
in Asia. It is based on the bibliometric information from SCI-Expanded database during the time period of 1995–2004. We show
that China has been developing fast in semiconductor research, and become the second productive country in Asia as reflected
by the publication profile. The evidences indicate a significant increasing trend in the research efforts and readership among
Asian countries. Similar to the scientists in Japan and South Korea, Chinese scientists were more inclined to work in larger
groups, typically 4 or more authors. The assessment of research quality is further conducted based on citation-based measures.
As benchmarks, two western countries, namely USA and Germany, have been compared in the citation analysis. It is revealed
that the impacts of research outputs in the Asian countries, except for Japan, have been badly incommensurate with their devoted
research efforts compared with USA and Germany. Like most of other Asian countries the research results of Chinese scientists
in semiconductor have a low international visibility despite their strong research efforts and increasingly large domestic
readership. The application of Leimkuhler curve illustrates vividly the inequality of citation times among the compared countries.
Furthermore, the Gini Indices of each country and each pair of countries are calculated which illustrates again the inequality
of informetric productivities. 相似文献
185.
186.
S. V. Prikhodko Y. Ma A. J. Ardell D. G. Isaak J. D. Carnes S. Moser 《Metallurgical and Materials Transactions A》2003,34(9):1863-1868
The adiabatic elastic stiffness constants C
ij of Ni-Si single-crystal solid-solution alloys of two slightly different compositions, 10.78 and 11.17 at. pct Si, were measured
over the temperature range from 20 °C to 900 °C using the rectangular parallelepiped resonance method. The isotropic elastic
constants of the polycrystalline ordered intermetallic compound Ni3Si containing 23 at. pct Si were also measured over this temperature range. Values of the C
ij for Ni3Si were estimated from the data on the polycrystalline alloy, as well as from published data in the literature on isomorphous
ternary ordered intermetallic compounds containing different amounts of Si. Using measured values and previously published
data, the stiffness constants of Ni3Ti were estimated; these are the only available data on this alloy. The estimated single-crystal elastic constants of Ni3Si, as well as the experimentally measured bulk modulus, are considerably smaller than published values calculated from first-principles
methods. The same is true for the C
ij of Ni3Ti, but the discrepancies are smaller. 相似文献
187.
188.
2-巯基苯并噻唑衍生物摩擦学性能的研究 总被引:4,自引:0,他引:4
合成了S—(1—(2—苯并噻唑基巯基)—2—羟基)—丙基N,N—二烷基二硫代氨基甲酸酯和S—(1—(2—苯并噻唑基巯基)—2—乙酰基)—丙基N,N—二烷基二硫代氨基甲酸酯两种化合物。运用IR、MS、HNMR和元素分析等分析方法对其结构进行表征。用四球试验、HQ—l环块试验分别考察了其对润滑油的极压承载能力及抗磨减摩性能的影响。结果表明:在350SN中性油中添加所合成的化合物后可以显著降低四球长磨后磨斑直径、有效地降低摩擦副之间的摩擦系数,拥有优良的摩擦学性能。 相似文献
189.
煤基链篦机-回转窑一步法直接还原设备改造及技术操作要点 总被引:2,自引:0,他引:2
本文主要论述了煤基链篦机-回转窑一步法直接还原关键设备改造及有关技术操作要点,并提出了进一步提高产量,稳定操作,延长作业周期,降低生产成本的技术改造方案。 相似文献
190.
论述了几种三相交流异步电动机的起动方式及其优缺点 ,介绍了新型的电子软启动方式在我厂深井泵电动机上的应用及取得的运行效果 ,为电动机软启动方式在工矿企业中的应用提供了应用经验。 相似文献