首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   37篇
  免费   2篇
  国内免费   2篇
化学   6篇
综合类   1篇
数学   30篇
物理学   4篇
  2019年   3篇
  2018年   1篇
  2016年   1篇
  2013年   5篇
  2012年   1篇
  2011年   1篇
  2009年   1篇
  2008年   1篇
  2007年   2篇
  2006年   4篇
  2005年   2篇
  2004年   3篇
  2001年   3篇
  1999年   1篇
  1998年   2篇
  1997年   1篇
  1996年   1篇
  1994年   3篇
  1993年   1篇
  1988年   1篇
  1985年   1篇
  1984年   1篇
  1980年   1篇
排序方式: 共有41条查询结果,搜索用时 15 毫秒
1.
对于任意秩有限总体,在二次损失下,有关文献已给出了线性可预测变量在齐次线性预测类中的唯一线性Minimax预测.本文在正态假设下,证明了这个线性Minimax预测也是线性可预测变量在一切预测类中的唯一Minimax预测.  相似文献   
2.
ABSTRACT

Interaction between a zinc porphyrin (ZnPor) as the end-group and poly(9,9-di-n-octylfluorene-2,7-vinylene) (PFV) as the main chain in a porphyrin end-modified fluorescent conjugated polymer, ZnPFV, was studied by time-resolved electron paramagnetic resonance (EPR) and fluorescence spectroscopy. While fluorescence from the PFV part of ZnPFV showed a spectral profile almost identical to that of a PFV oligomer without end-modification, the emission spectrum of the ZnPor part exhibited a much broader profile compared to that of the reference zinc porphyrin monomer. Based on the analysis of lifetimes and quantum yields, it was found that radiative rate constant of the ZnPor part was enhanced by nearly three times. The observed unusual enhancement in the radiative rate constant was rationalised in terms of a partial π-conjugation between the end group and the main chain, as a result of co-planarisation in fluid solution. On the other hand, the time-resolved EPR spectrum of ZnPFV at 100?K basically showed a similar spectral pattern to that of the reference zinc porphyrin, but with significant differences in zero-field spitting parameters and initial population ratios. The π-system of the excited triplet state is deduced to deviate from D4h symmetry in the end zinc porphyrin groups. The obtained results show that interaction of the porphyrin end group with the main chain of the polymer significantly influences the excited singlet state properties of the porphyrin, while its triplet state properties were affected to a lesser extent.  相似文献   
3.
刘郁文  喻胜华 《数学杂志》2007,27(2):165-172
本文研究了一般Gauss-Markov模型中线性可预测变量的线性预测的可容许性.在给出线性预测可容许性定义的基础上,通过构造一个特殊的常量矩阵D0,分别得到了齐次和非齐次线性预测类中可容许的充要条件.  相似文献   
4.
自反B空间中集值增过程的对偶投影   总被引:8,自引:0,他引:8  
聂赞坎  张文修 《数学学报》1996,39(3):419-429
假定A是以自反Banach空间中弱紧凸集为值的集值增过程,本文研究了非负有界可测过程关于A的积分以及A在乘积可测空间上生成的集值测度,证明了每个可积集值增过程存在唯一对偶可选(可料)投影.  相似文献   
5.
6.
《随机分析与应用》2013,31(3):449-474
Abstract

In a theory similar to one of real-valued stochastic processes, in this paper, we investigate the projection and dual projection for fuzzy stochastic processes. First, the related concepts of fuzzy stochastic processes are introduced, such as adaption, measurability, optionality, predictability, etc. Subsequently, we study fuzzy stochastic integral and fuzzy measure generated by increasing fuzzy stochastic processes. Moreover, (dual) projection w.r.t. (increasing) fuzzy stochastic processes are discussed. We prove the existence and uniqueness of (dual) optional (predictable) projection for (increasing) fuzzy stochastic processes.  相似文献   
7.
Anionic polymerizations of four new dual-functionalized styrene and α-methylstyrene derivatives, 3-(4-(4-isopropenylphenoxy)butyl)styrene ( 4 ), 3-(4-(2-isopropenylphenoxy)butyl)-α-methylstyrene ( 5 ), 4-(4-(4-isopropenylphenoxy)butyl)-α-methylstyrene ( 6 ), and 4-(4-(2-vinylphenoxy)butyl)styrene ( 7 ), were carried out in THF at -78 °C with sec-BuLi as an initiator. Both 4 and 5 underwent anionic polymerization in a living manner to quantitatively afford functionalized polystyrenes and poly(α-methylstyrene)s having α-methylstyrene moiety in each monomer unit and precisely controlled chain lengths. On the other hand, insoluble polymers were obtained by the anionic polymerization of 6 and 7 under the same conditions. The positional effect of substituent on anionic polymerization was discussed.  相似文献   
8.
A process which has just one jump, and whose time parameter is the positive quadrant [0, ∞] × [0, ∞], is considered. Following Merzbach, related stopping lines are introduced, and the filtration {Ft1,t23} considered in this paper is such that, modulo completion, the σ-field Ft1,t23 is the Borel field on the region
Lt1,t2={(s1,s2); 0?s1?t1or0?s2?t2}
, together with the atom which is the complement in Ω = [0, ∞]2 of Lt1,t2. Optional and predictable projections of related processes are defined, together with their dual projections, and an integral representation for martingales is obtained.  相似文献   
9.
Set-indexed martingales and submartingales are defined and studied. The admissible function of a submartingale is defined and some class (D) conditions are given which allow the extension of the function to a -additive measure on the predictable -algebra. Then, we prove a Doob-Meyer decomposition: A set-indexed submartingale can be decomposed into the sum of a weak martingale and an increasing process. A hypothesis of predictability ensures the uniqueness of this decomposition. An explicit construction of the increasing process associated with a submartingale is given. Finally, some remarks, about quasimartingales are discussed.Research supported by a grant from the Natural Sciences and Engineering Research Council of Canada. Dept. of Math. University of Ottawa, Ottawa, Ontario, Canada, K1N 6N5.The third author wishes to thank Professor Ivanoff and Dr. Dozzi for their kind hospitality. Dept. of Math. & Comp. Sci. Bar-Ilan University, Ramat-Gan 52900, Israel.  相似文献   
10.
本文主要讨论两指标局部平方可积鞅的停止变换问题及Wiener过程的鞅刻划和停止问题。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号