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121.
An efficient protocol for cobalt (II)-catalyzed regioselective aryl C8H bond alkoxylation of 1-naphthylamine derivatives with readily available alcohols has been developed, demonstrating an efficient approach to 8-alkoxy-1-naphthylamine derivatives with good functional group tolerance. Note that the picolinamide moiety as a bidentate directing group may play a key role in this regioselective transformation. 相似文献
122.
Yusheng Wang Nahong Song Na Dong Shijun Luo Min Jia Kai Xu Yafeng Zheng Hong Ling Meng Li 《Physics letters. A》2019,383(23):2765-2771
We carry out first-principles calculations within density-functional theory to investigate the structural, electronic and magnetic properties of 4d transition metal (TM) decorated monolayer black phosphorene (BP). The results indicate that the TM adsorption on BP can have dilute magnetic semiconductor (DMS) properties. The spin polarized semiconducting state is realized in BP by adsorption of Y, Nb and Ru, while a half-metal state is obtained by Tc adsorption. In the case of two same types of TMs adsorption on BP, only [email protected] shows DMS state. In particular, two different types of TMs decorated BP can induce magnetic moments, localized mainly on the 4d TMs and the neighboring P atoms. Furthermore, the 4d TMs may enrich the electronic properties of BP, such as half-metallic, metallic and semiconducting features. These findings suggest that the 4d TM adsorbed BP can be used as a potential next-generation spintronics and magnetic storage material. 相似文献
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Construction of improved estimators in multiparameter estimation for continuous exponential families
A unified theory of simultaneous estimation of parameters for the continuous exponential family is presented. Estimators are constructed that improve on the standard ones (the maximum likelihood, UMVUE or best invariant estimator). These improved estimators shift the standard ones towards possibly non-zero points or data based points. 相似文献
127.
Kam-Wah Tsui 《Annals of the Institute of Statistical Mathematics》1986,38(1):45-56
Summary In multiparameter estimation for multivariate discrete distributions with infinite support, inadmissibility problems in situations
where the multivariate probability distribution function isnot a product of the one-dimensional marginal probability distribution functions have previously been unexplored. This paper
examines the inadmissibility problem in some of these situations. Special attention is given to estimating the mean of a negative
multinomial distribution. In estimating the mean vector, certain Clevenson-Zidek type estimators are shown to be uniformly
better than the usual estimator under a large class of generally scaled squared loss functions. Some of the results are generalized
to other multivariate discrete distributions and to situations where several independent negative multinomial distributions
are considered. 相似文献
128.
本文配合KrF激光器的设计,对其动力学过程作了零维模拟计算,并与国内外实验结果进行了比较。通过模拟研究,对KrF激光器本征效率的提高、激光器对入射束流的要求以及对激光腔体的设计等都提出了很好的建议与简单实用的计算模式。 相似文献
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