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On the average crosscap number II: Bounds for a graph

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Science china Mathematics 2007年第2期50卷 292-304页

作者： Yi-chao CHEN & Yan-pei LIU College of Mathematics and Econometrics, Hunan university, Changsha 410082, china department of Mathematics, Beijing Jiaotong university, Beijing 100044, china 1. College of Mathematics and Econometrics Hunan University Changsha 410082 China 2. department of Mathematics Beijing Jiaotong University Beijing 100044 China

The bounds are obtained for the average crosscap number. Let G be a graph which is not a tree. It is shown that the average crosscap number of G is not less than 2 β(G?1/2 β(G?1 β(G) and not larger than β(G). Furt... 详细信息

关键词： average genus average crosscap number bounds 05C10

Functions of HDA-4 in regulating long-term memory and HDA-4-mediated genetic pathways in Caenorhabditis elegans

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Functions of HDA-4 in regulating long-term memory and HDA-4-...

The variation of transition location in response to the variation of the amplitudes of initial disturbances

中国神经科学学会第四次会员代表大会暨第七届全国学术会议

作者： Ya-Ou HU~(1,2),Da-Yong WANG~(1,2) 1 department of Genetics and Developmental Biology,Southeast university,nanjing 210009,china 2 Key Laboratory of Developmental Genes and Human Disease,Ministry of Education,nanjing 210009,china

＜正＞HDA-4,which encodes the classⅡhistone deacetylase,acts as an important transcriptional co-repressor by directly interacting with transcription factors in ***,roles of the HDA-4 in regulating the functions of nervous system are still largely *** organism Caenorhabditis elegans has been proved to be well suited for dissecting the molecular and cellular mechanism of learning and memory behaviors,and systematic studies have been performed in molecular and genetic control of behavioral plasticity in *** the present study,using classic thermotaxis model,we show that HDA-4 may play a key role in regulating long-term memory（LTM）.HDA-4 knockout animals exhibited significantly severe defects in long-term memory,whereas no obvious defects were observed for shortterm memory in *** addition,no significantly severe defects of locomotion behaviors,reproduction and metabolism were found in HDA-4 knockout and knockdown animals,which further conforms the functions of HDA-4 in controlling *** mutation of HDA-4 also did not affect the neural activities of cholinergic,GABAergic,dopaminergic, and serotonergic systems,as well as the ASE,AWA,AFD sensory neurons and AIY ***-4 was expressed in the cytoplasm at the early stages of larva and translocated to the nucleolus at the late stages of larva and adult animals, suggesting the possibly temporal control of HDA-4 in regulating ***,the tissue activity in nervous system explained most of the function of HDA-4 regulating LTM,whereas the tissue activity of HDA-4 in non-neural tissues resulted in no marked LTM defects compared to wild type,which indicates that function of HDA-4 in nervous system is predominantly required for LTM *** interaction analysis by constructing a series of double mutants further suggests that the function of HDA-4 was dependent on the expression of CMK-1 and UNC-43,but not dependent on the expression of its target MEF-2 and 14-3-3 prot

关键词： C.elegans long-term memory HDA-4 genetic interaction

来源： cnki会议评论

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Science china(Physics,Mechanics & Astronomy) 2010年第6期53卷 1109-1115页

作者： SU CaiHong & ZHOU Heng department of Mechanics,Tianjin university,Tianjin 300072,china 1. department of Mechanics Tianjin University Tianjin 300072 China

The transition location of a boundary layer depends on the amplitude and characteristic of initial disturbances. The larger the amplitude and the amplification rate of the initial disturbances are,the more upstream the transition location is. However,the environment surrounding the flying vehicle is variable,so the amplitude and characteristic of the disturbances triggered in the boundary layer through receptivity are also variable. In this paper,how the transition location varies in response to the variation of the initial disturbance amplitudes is studied by using direct numerical simulation. The results show that if the initial disturbance amplitudes become smaller,the transition location moves downstream correspondingly,but there is a time delay compared to the time of arrival of the disturbances with reduced amplitudes. Moreover,the speed of moving downstream is appreciably lower than the propagation speed of the disturbances. On the other hand,if the amplitudes of the initial disturbances recover their original value,the transition would immediately take place whenever the disturbances reach the former transition location,but the laminar flow between the new and old transition locations would not become turbulent immediately. Theoretical explanations are provided based on the transition mechanism found by our group.

关键词： transition boundary layer stability modification of mean flow direct numerical simulation

Synthesis of todorokite by refluxing process and its primary characteristics

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Science china earth sciences 2004年第8期47卷 760-768页

作者： FENG Xionghan1, LIU Fan1, TAN Wenfeng1, LIU Xiangwen2 & HU Hongqing1 1. College of Resources and Environment, Huazhong Agricultural university, Wuhan 430070, china 2. Testing Center, china university of Geosciences, Wuhan 430074, china 1. College of Resources and Environment Huazhong Agricultural University 430070 Wuhan China 2. Testing Center China University of Geosciences 430074 Wuhan China

Single phase and well-crystallined todorokite were synthesized by heating and refluxing process from birnessite as a precursor. The average chemical composition of the synthesized todorokites by refluxing for 8 h and for 24 h was Mg0.19MnO2.11(H2O)1.15 and in0.17-MnO2.10(H2O)0.88, respectively. The crystallinity of the todorokite increased and no other phase was produced with increasing refluxing period. The synthesized todorokites have the same morphologies and the similar structural characteristics with the natural todorokites and hydro-thermally synthesized samples. The chemical compositions of the synthetic tordorokites by refluxing process are close to those of todorokites synthesized by hydrothermal process, except a higher average oxidation state of Mn for the former.

关键词： todorokite,birnessite,manganese oxide,refluxing,hydrothermal,synthesis.

SELF-CANCELLATION OF MODULES HAVING THE FINITE EXCHANGE PROPERTY

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Chinese Annals of Mathematics,Series B 2005年第1期26卷 111-118页

作者： CHENHUANYIN departmentofMathematics HunanNormalUniversityChangsha410006China

Self-cancellation of modules having the finite exchange property is introduced. If a right R-module M has the finite exchange property, it is shown that M has selfcancellation if and only if EndR(M) is a strongly sepa... 详细信息

关键词： Self-cancellation Strong separativity

Characteristics of shape memory and superelasticity for TiNi thin films

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中国有色金属学会会刊：英文版 2000年第3期10卷 375-377页

作者： HE Zhi rong(贺志荣) 1, S.Miyazaki 2 1. department of Mechanical Engineering, Shaanxi Institute of Technology, Hanzhong 723003, P.R.china 2. university of Tsukuba, Japan Shaanxi Inst Technol Dept Mech Engn Hanzhong 723003 Peoples R China Univ Tsukuba Tsukuba Ibaraki 305 Japan

TiNi shape memory alloy thin films were deposited by using a RF magnetron sputtering apparatus. The transformation and shape memory characteristics of the thin films have been investigated by using DSC and tensile tes... 详细信息

关键词： TiNi alloy shape memory effect superelasticity thin film

Anatomical reinvestigation of Archaeopteris macilenta from the Upper Devonian(Frasnian) of South china

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Journal of Systematics and Evolution 2011年第6期49卷 590-597页

作者： Yun GUO De-Ming WANG(Key Laboratory of Orogenic Belts and Crustal Evolution,department of Geology,Peking university,Beijing 100871,china) (Key Laboratory of Orogenic Belts and Crustal Evolution Department of Geology Peking University Beijing 100871 China) *Correspondence: De-Ming WANG *Correspondence: E-mail: dmwang@*** Tel.: 86-10-62761095 Fax: 86-10-62751187.

Archaeopteris macilenta is one of the most widespread plants in the Late *** on fossils from the Frasnian Huangjiadeng Formation,Yichang District of Hubei Province,for the first time we study in detail the anatomy of this progymnosperm plant in South *** axes are protostelic with three xylem sympodia and lack secondary *** axes are eustelic,bearing eight sympodia and a thin band of secondary *** symmetrical sympodia of mesarch primary xylem produce traces of appendages in a spiral *** macilenta and ***(***)are dominant in the Frasnian and Famennian,*** with these two species from other tectonic plates indicate consistent stelar *** spread,continuous occurrence,and identical anatomy during the Late Devonian indicate that Archaeopteris survived the Frasnian-Famennian extinction *** this time,endemic genera and cosmopolitan taxa,including Archaeopteris,suggest the palaeogeographic isolation of South china and certain associations with other plates.

关键词： anatomy Archaeopteris Late Devonian palaeogeography progymnosperms South china.

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基于贝叶斯理论的水文线型参数不确定性分析

水电能源科学 2009年第6期27卷 15-19页

作者：桑燕芳王栋吴吉春南京大学地球科学与工程学院江苏南京210093

针对水文频率计算线型参数估计结果存在误差与不确定性及相应水文设计结果存在风险等问题,提出了基于贝叶斯理论的水文线型参数不确定性分析方法及相应的水文频率计算方法。通过贝叶斯采样得到所选线型中参数的后验分布并计算参数后验... 详细信息

针对水文频率计算线型参数估计结果存在误差与不确定性及相应水文设计结果存在风险等问题,提出了基于贝叶斯理论的水文线型参数不确定性分析方法及相应的水文频率计算方法。通过贝叶斯采样得到所选线型中参数的后验分布并计算参数后验分布特征值确定不同置信区间,定量分析和描述线型参数的不确定性,根据参数的后验分布求得指定频率对应水文设计值的概率分布,在分析设计值概率分布特征值及不同置信区间的基础上,实现对水文设计结果不确定性和风险性的定量描述和估计。实例分析结果表明,水文线型参数及水文设计结果的不确定性客观存在,该方法用于研究线型参数不确定性行之有效,作出"概率值"的概率预报结果合理可靠。

关键词：水文时间序列水文频率分析贝叶斯理论不确定性风险

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借助梯形分割的点面包含分析

计算机工程与应用 2009年第29期45卷 49-51,124页

作者：崔璨王结臣沈定涛南京大学地理信息科学系南京210093

在诸多研究领域中,判断点是否在多边形内是一个非常基本的问题。在分析了解决这一问题的传统方法基础上,提出了一种基于梯形分割的点面包含算法。该算法将多边形分割成若干个梯形网格单元,将判断点是否位于多边形内的问题转化为判断点... 详细信息

在诸多研究领域中,判断点是否在多边形内是一个非常基本的问题。在分析了解决这一问题的传统方法基础上,提出了一种基于梯形分割的点面包含算法。该算法将多边形分割成若干个梯形网格单元,将判断点是否位于多边形内的问题转化为判断点是否位于梯形网格单元中这一问题。算法已用于GIS平台软件相应的包含分析模块,试验结果证明该算法稳定可靠、适用于任意复杂多边形而无需对奇异情况进行单独处理。

关键词：梯形分割点面包含分析空间分析地理信息系统