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101.
Wen Zhang Hui Huang Yu Ding Margherita Gavagnin Ernesto Mollo Guido Cimino Yue‐Wei Guo 《Helvetica chimica acta》2006,89(4):813-820
Three new polyoxygenated steroids, muricesteroid ( 1 ), and menellsteroids A ( 2 ) and B ( 3 ), were isolated from two species of the South China Sea gorgonian Muricella flexuosa and Menella verrucosa Brundin , respectively. The structures of these new compounds were elucidated on the basis of extensive spectroscopic analysis, chemical methods and comparison with known related compounds. 相似文献
102.
采用同步辐射能量色散X射线衍射技术、激光加热技术和金刚石对顶砧(DAC)高压装置,在温度为2 000 K和压力为23 GPa的范围内,对采自地幔二辉橄榄岩中的顽火斜方辉石,进行了原位的高温高压能量色散X射线衍射(EDXRD)测量。实验结果表明:当压力为15.3 GPa、温度为1 600 K时(相当于地球内部410 km处的地震波不连续界面的温压环境),顽火斜方辉石转变为橄榄石的β相——瓦兹利石(Wadsleyite)相;继续加温加压至2 000 K、23 GPa时(相当于地球内部670 km处的地震波不连续界面的温压环境),顽火斜方辉石相变为钛铁矿(Ilmenite)结构和钙钛矿(Perovskite)结构的混和相。实验结果进一步证明,在地幔中存在的两个地震波不连续界面是由橄榄石、顽火斜方辉石等矿物的相变引起的。 相似文献
103.
It is proved that the variety of relevant disjunction lattices has the finite embeddability property. It follows that Avron's relevance logic RMI min has a strong form of the finite model property, so it has a solvable deducibility problem. This strengthens Avron's result that RMI min is decidable. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
104.
Parallel to Cox's [JRSS B34 (1972) 187-230] proportional hazards model, generalized logistic models have been discussed by Anderson [Bull. Int. Statist. Inst. 48 (1979) 35-53] and others. The essential assumption is that the two densities ratio has a known parametric form. A nice property of this model is that it naturally relates to the logistic regression model for categorical data. In astronomic, demographic, epidemiological, and other studies the variable of interest is often truncated by an associated variable. This paper studies generalized logistic models for the two-sample truncated data problem, where the two lifetime densities ratio is assumed to have the form exp{α+φ(x;β)}. Here φ is a known function of x and β, and the baseline density is unspecified. We develop a semiparametric maximum likelihood method for the case where the two samples have a common truncation distribution. It is shown that inferences for β do not depend the nonparametric components. We also derive an iterative algorithm to maximize the semiparametric likelihood for the general case where different truncation distributions are allowed. We further discuss how to check goodness of fit of the generalized logistic model. The developed methods are illustrated and evaluated using both simulated and real data. 相似文献
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Orlicz-Sobolev空间的中点局部一致凸性 总被引:2,自引:0,他引:2
本文研究了Orlicz-Sobolev空间的中点局部一致凸性,通过结合Orlicz空间和Sobolev空间的技巧得到分别赋Luxemburg范数和赋Orlicz范数的Orlicz-Sobolev空间具有中点局部一致凸性的充要条件. 相似文献
108.
Weidong Gao Meiqiong Zhan Shuhai Fan Janda Shao Zheng-Xiu Fan 《Applied Surface Science》2005,250(1-4):195-202
The laser-induced damage (LID) behavior of narrow-band interference filters was investigated with a Nd:YAG laser at 1064 nm under single-pulse mode and free-running mode. The absorption measurement of such coatings was performed with surface thermal lensing (STL) technique. The damage morphologies under the two different laser modes were also studied in detail. It was found that all the filters exhibited a pass-band-center-dependent absorption and laser-induced damage threshold (LIDT) behavior, but the damage morphologies were diverse. The explanation was given with the analysis of the electric field distribution and the operational behavior of the irradiation laser. 相似文献
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