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961.
Science Letters:On stochastic optimal control of partially observable nonlinear quasi Hamiltonian systems 总被引:4,自引:0,他引:4
A stochastic optimal control strategy for partially observable nonlinear quasi Hamiltonian systems is proposed. The optimal control forces consist of two parts. The first part is determined by the conditions under which the stochastic optimal control problem of a partially observable nonlinear system is converted into that of a completely observable linear system. The second part is determined by solving the dynamical programming equation derived by applying the stochastic averaging method and stochastic dynamical programming principle to the completely observable linear control system. The response of the optimally controlled quasi Hamiltonian system is predicted by solving the averaged Fokker-Planck-Kolmogorov equation associated with the optimally controlled completely observable linear system and solving the Riccati equation for the estimated error of system states. An example is given to illustrate the procedure and effectiveness of the proposed control strategy. 相似文献
962.
Jinsong Li Dayuan Chen Zhiming Han Ziyu Zhu Duancheng Wen Qingyuan Sun Zhonghua Liu Minkang Wang Li Lian Jun Du Pengyan Wang Hemin Zhang 《科学通报(英文版)》2002,47(6):467-469
Interspecies somatic nuclear transfer (NT) may provide a new approach for preservation of the endangered rare species. Previous
interspecies cloning studies have shown that a nucleus from a quiescent somatic cell supports early development of reconstructed
embryos in the ooplasm from another species. In this study, we transferred nonquiescent somatic cells from a giant panda into
the perivitelline space of the enucleated rabbit oocytes. After electrofusion (at the rate of 71.6%) and electrical activation,
4.2% of the panda-rabbit reconstructed embryos developed to blastocyst in vitro. For improving the development rate of reconstructed embryos, we used serial NT in this study, i.e. blastomeres from reconstructed
morulae were transferred into the perivitelline space of the enucleated rabbit oocytes. The fusion rates in the groups of
serial I, serial II and serial III were 79.5%, 84.1% and 78.0%, respectively, having no difference with that of somatic group.
And the blastocyst rates in serial NT groups were 19.4%, 13.5% and 10.3%, respectively, which are significantly higher than
that in somatic NT group. These results indicate that the nuclei from nonquiescent somatic cells can support early development
of reconstructed embryos and serial NT can improve the development rate of interspecies reconstructed embryos.
These authors contributed equally to this work. 相似文献
963.
964.
A primitive sarcopterygian fish with an eyestalk 总被引:3,自引:0,他引:3
The discovery of two Early Devonian osteichthyan (bony fish) fossils has challenged established ideas about the origin of osteichthyans and their divergence into actinopterygians (teleosts and their relatives) and sarcopterygians (tetrapods, coelacanths, lungfishes and related groups). Psarolepis from China and an unnamed braincase from Australia combine derived sarcopterygian and actinopterygian characters with primitive features previously restricted to non-osteichthyans, suggesting that early osteichthyan evolution may have involved substantial parallellism between sarcopterygians and actinopterygians. But interpretation of these fossils has been hampered by poor phylogenetic resolution. Here we describe a basal sarcopterygian fish, Achoania gen, et sp. nov., that fills the morphological gap between Psarolepis and higher sarcoptergyians. We also report the presence of eyestalk attachments in both Achoania and Psarolepis, showing that this supposedly non-osteichthyan feature occurs in basal sarcopterygians as well as the actinoptergyian-like Australian braincase. 相似文献
965.
Wang Li-na Fei Ru-chun Liu Zhu . State Key Laboratory of Software Engineering Wuhan University Wuhan Hubei China . Department of Information Engneering Benxi College of Metallurgy Benxi Liaoning China . School of Information Science Engineering Northeastern University Shenyang Liaoning China 《武汉大学学报:自然科学英文版》2003,8(4):1065-1069
0 IntroductionAblockcipherwithoutdataextensionorexpressionisaper mutation .Thesecurityofablockcipherschemeiscorrela tivewiththe permutations.Quicktrickle permutation[1 ] canmakethedatadisorderedwhenactingatthedataandmakeallprobabledistancebetweentwoelementsappear,soithasgoodcryptographicpropertiesandcanbeusedintheblockcipherwhichrequireshighsecurity.Aprivatekeyblockcipherisapermutationinn dimensionvectorspaceoverF2 atthecontrolofakey[2 ,3] .Moreover,manyblockciphersusepermutationstoexecuteso… 相似文献
966.
Melanoma mouse model implicates metabotropic glutamate signaling in melanocytic neoplasia 总被引:3,自引:0,他引:3
Pollock PM Cohen-Solal K Sood R Namkoong J Martino JJ Koganti A Zhu H Robbins C Makalowska I Shin SS Marin Y Roberts KG Yudt LM Chen A Cheng J Incao A Pinkett HW Graham CL Dunn K Crespo-Carbone SM Mackason KR Ryan KB Sinsimer D Goydos J Reuhl KR Eckhaus M Meltzer PS Pavan WJ Trent JM Chen S 《Nature genetics》2003,34(1):108-112
967.
基于MFC的Windows下多进程消息通信技术及应用 总被引:1,自引:0,他引:1
介绍了一种基于MFC的Windows下多进程通信方法和技术——消息通信,简介了MFC下的消息通信机制,并采用了“钩子”机制和转发机制实现了在任意类下的消息通信。同时根据实际的开发经验,举出了一个使用MFC开发的详细实例。 相似文献
968.
阐述了采用Netfilter/iptables技术来实现NAT的缘由 ,并分析了此项技术在Linux内核 2 .4中的一个重要新特性 ,即“连接跟踪” ;着重讨论了提高基于配有Linux操作系统的普通PC机上的NAT性能的方法 ,包括重编内核 ,防止空对话及修改tcp连接超时设定 ;通过一组系统状态监测曲线图证明这样一个廉价系统作为一些昂贵的路由设备的替代是稳定可靠的 相似文献
969.
Hydrogen storage of aligned multi-walled carbon nanotubes (a-MWNTs),non-aligned MWNTs(n-MWNTs) and graphite electrodes are studied by the electro-chemical measurements .The electrodes are prepared by mixing carbon nanotubes (CNTs) copper powder and ptfe binder in a weight ratio of 1:5:3 and compressing the mixture into porous nickel collector,The results show that the electrochemical hydrogen storage capacity of the a-MWNT electrode is up to 1625 mAh/g corresponding to a high hydrogen storage of 5.7 wt% ,which is 10 times that of graphite electrode and is 13 times that of n-MWNT electrode, suggesting that a-MWNTs are promising materials for electrochemical hydrogen storage. 相似文献
970.
SHENYongqiang XUESaifeng ZHAOYunjie ZHUQianjiang TAOZhu 《科学通报(英文版)》2003,48(24):2694-2697
Self-assembled complexes between cage com-pounds cucurbit[n = 5—8]urils and hexamethylenetetramine were studied by using NMR techniques. Experimental results reveal that hexamethylenetetramine can lid cucurbit[5]uril to forming self-assembled capsules in which nothing is encap-sulated yet; the cavity of the cucurbit[7]uril can accommo-date a hexamethylenetetramine molecule to form a self- assembled host-guest inclusion. Moreover, both the cavity interaction of the cucurbit[7]uril with hexamethylenetetra-mine稨Cl and the portal interaction of the dipole carbonyl of the cucurbit[7]uril with hexamethylenetetramine稨Cl lead to form self-assembled capsules in which the hexamethylene-tetramine稨Cl are encapsulated in the hexamethylenetetra-mine稨Cl lidded cucurbit[7]uril. Although the structures of the portal and cavity to cucurbit[5]uril are similar, there is no obvious interaction between decamethylcucurbit[5]uril and hexamethylenetetramine, and also between cucurbit [6]uril or cucurbit[8]uril and hexamethylenetetramine. 相似文献