检索结果-南通市图书馆

Dynamic access clustering selecting mechanism based on Markov decision process for MANET

在线全文

学校读者我要写书评

暂无评论

The Journal of China Universities of Posts and Telecommunications 2007年第4期14卷 88-92页

作者： wang Dao-yuan TIAN hui Wireless Technology Investigate Laboratory Beijing University of Posts and Telecommunications Beijing 100876 China

Clustering is an important method in the mobile Ad-hoc network（MANET）. As a result of their mobility, the cluster selection is inevitable for the mobile nodes during their roaming between the different clusters. In this study, based on the analysis of the cluster-selecting problem in the environment containing multiple clusters, which are overlaying and intercrossing, a novel dynamic selecting mechanism is proposed to resolve the dynamic selection optimization of roaming between the different clusters in MANET. This selecting mechanism is also based on the consideration of the stability of communication system, the communicating bandwidth, and the effect of cluster selecting on the communication and also in accordance with the Markov decision-making model.

关键词： MANET roam cluster selection effect

Congruence Triples on Regular Semigroups and Their Generalizations

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2011年第8期27卷 1611-1620页

作者： Li Min wang hui yuan YANG School of Mathematics South China Normal University Guangzhou 510631 P. R. China

In this paper, we introduce the concept of VT-congruence triples on a regular semigroup S and show how such triples can be constructed by nsing the equivalences on S/L, S/R and the special congruences on S. Also, such congruence triples are characterized so that an associated congruence can be uniquely determined by a given congruence triple. Moreover, we also consider the VH-congruence pairs on an orthocryptogroup.

关键词： Regular semigroup orthodox semigroup orthocryptogroup congruence normal equivalence

Application of Et_3NHCl-AlCl_3 Ionic Liquid as an Initiator in Cationic Copolymerization of 1, 3-Pentadiene with Styrene

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2006年第1期17卷 117-120页

作者： yuan yuan wang hui SUN Juan LI Dong JIANG Li Yi DAI Center for the Chemistry of Ionic Liquids East China Normal University （E.C.N.U） Shanghai 200062

The random copolymer poly （1, 3-pentadiene-co-styrene） formed through cationic copolymerization using the ~ethylamine hydrochloride and hydrous aluminium chloride （Et3NHCl-AlCl3） room temperature ionic liquid as initiating agent in toluene was analyzed using IR spectra in conjunction with gel permeation chromatography （GPC）. The room temperature ionic liquid was found to have high initiatic activity for copolymerization.

关键词： Et3NHCl-AlCl3 ionic liquid 1 3-pentadiene styrene cationic copolymerization.

Nuclear power plant fault diagnosis based on genetic-RBF neural network

在线全文

学校读者我要写书评

暂无评论

Journal of Marine Science and Application 2006年第3期5卷 57-62页

作者： SHI Xiao-cheng XIE Chun-ling wang yuan-hui College of Power and Nuclear Energy Harbin Engineering University Harbin 150001 China

It is necessary to develop an automatic fault diagnosis system to avoid a possible nuclear disaster caused by an inaccurate fault diagnosis in the nuclear power plant by the operator. Because Radial Basis Function Neural Network (RBFNN) has the characteristics of optimal approximation and global approximation. The mixed coding of binary system and decimal system is introduced to the structure and parameters of RBFNN, which is trained in course of the genetic optimization. Finally, a fault diagnosis system according to the frequent faults in condensation and feed water system of nuclear power plant is set up. As a result, Genetic-RBF Neural Network (GRBFNN) makes the neural network smaller in size and higher in generalization ability. The diagnosis speed and accuracy are also improved.

关键词： geneticalgorithm (GA) RBF neural network nuclear power plant

The effect of celecoxib on tissue factor expression in pancreatic cancer cells

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Journal 2007年第20期120卷 1753-1756页

作者： wang hui-yuan YANG Yin-mo ZHUANG Yan CHEN Huan-nian WAN yuan-lian HUANG Yan-ting Department of General Surgery Xuanwu Hospital of Capital Medical University Beijing 100053 China Department of General Surgery Peking University the First Hospital Beijing 100034 China

Background Tissue factor （TF） is overexpressed in many malignant tumours and is linked to the pathogenesis and prognosis of such malignancies. In vitro studies have proved that reduced expression of TF has inhibitory effect on the angiogenesis and cell proliferation of the malignant tumour. Therefore, TF suppression has been raised as a possible treatment for malignant tumours. Here we investigated the effect of celecoxib on TF expression induced by tumour necrosis factor α （TNFα） in PANC-1 cells and a possible molecular mechanism underlvina the celecoxib effect.Methods Various doses of celecoxib solution were added to standard cell numbers of PANC-1 cells mixed with equal dose of TNFα for 6 hours. The expression of tissue factor was detected quantitatively by Western blot, whilst the activation of nuclear factor κB was tested by electromobility shift assay.Results As the doses of celecoxib increased, the tissue factor expression was decreased in PANC-1 cells and so was the activation of nuclear factor κB.Conclusions Celecoxib can downregulate the expression of tissue factor induced by TNFα in PANC-1 cells. This antitumour effect of celecoxib can be explained indirectly via its suppressive role in activation of nuclear factor κB.

关键词： pancreatic neoplasms tissue factor celecoxib

在线全文

学校读者我要写书评

暂无评论

高温高压下草酸脱羧反应中的拉曼光谱研究

光谱学与光谱分析 2012年第3期32卷 669-672页

作者：王慧媛郑海飞造山带与地壳演化教育部重点实验室北京大学地球与空间科学学院北京100871

应用水热金刚石压腔结合拉曼光谱技术研究了高温高压下草酸溶液的热稳定,使用拉曼光谱对其脱羧反应及产物进行监测。结果表明低温升温过程中,草酸的拉曼谱图中各个特征振动峰没有发生变化,随着温度的继续升高,其特征振动峰逐渐变弱。达... 详细信息

应用水热金刚石压腔结合拉曼光谱技术研究了高温高压下草酸溶液的热稳定,使用拉曼光谱对其脱羧反应及产物进行监测。结果表明低温升温过程中,草酸的拉曼谱图中各个特征振动峰没有发生变化,随着温度的继续升高,其特征振动峰逐渐变弱。达到一定温度后,羧基的拉曼特征峰消失,草酸发生脱羧反应:C2H2O4—2CO2+H2生成CO2和H2。高温高压下草酸发生热分解的温度压力之间呈线性关系,其线性回归方程为P(MPa)=12.839 T(K)-5 953.7,R2=0.99。草酸脱羧反应的摩尔体积变化与温度压力的关系为ΔV(***-1)=16.69-0.002P(MPa)+0.005 2T(K),R2=0.99。

关键词：拉曼光谱高温高压草酸脱羧反应摩尔体积变化

在线全文

学校读者我要写书评

暂无评论

卫星星系动力学状态对星系属性的依赖

天文学报 2017年第3期58卷 97-110页

作者：裴远王慧元中国科学技术大学天文学系合肥230026

基于Sloan Digital Sky Survey(SDSS)数据,采用van den Bosch等发展的自适应方法从星系样本中挑选出中央星系及其卫星星系,然后研究卫星星系速度弥散与中央星系/卫星星系属性的关系.和之前的研究一致,卫星星系平均速度弥散随着中央星系... 详细信息

基于Sloan Digital Sky Survey(SDSS)数据,采用van den Bosch等发展的自适应方法从星系样本中挑选出中央星系及其卫星星系,然后研究卫星星系速度弥散与中央星系/卫星星系属性的关系.和之前的研究一致,卫星星系平均速度弥散随着中央星系质量增大而增大,并且红中央星系所在星系群的速度弥散比蓝中央星系要大.发现平均而言,在红中央星系周围,卫星星系的速度弥散和其质量之间没有明显关联.但是在蓝中央星系周围,质量大的卫星星系速度弥散偏大,而红卫星星系的速度弥散要比蓝卫星星系偏大.进一步的研究表明,在相同的暗晕中,卫星星系速度弥散和卫星星系质量并不相关.有意思的是,如果红中央星系周围同时有红和蓝卫星星系,那么红卫星星系的速度要小,对其中的物理机制进行了初步的探讨.此外还发现,若中央星系周围只有红或蓝(质量大或小)的卫星星系时,有红(或质量大)的卫星星系所在的暗晕的速度弥散要大于有蓝(或者质量小)的卫星星系的暗晕,这表明卫星星系属性对于暗晕质量测量是有影响的.

关键词：星系暗晕星系运动学与动力学方法统计

在线全文

学校读者我要写书评

暂无评论

不同澄清剂对柿子醋澄清效果的研究

中国调味品 2014年第8期39卷 32-34页

作者：王君王媛慧山西农业大学食品科学与工程学院山西太谷030801

试验以柿子为原料,经固体发酵而制成柿子醋。柿子醋在生产与贮藏中存在着醋体颜色加深,返混等现象,为了提高酿造柿子醋的澄清度,减少柿子醋中沉淀物的含量,使用生产上常用的几种澄清剂对柿子醋澄清效果进行研究,结果表明,壳聚糖、PVPP... 详细信息

试验以柿子为原料,经固体发酵而制成柿子醋。柿子醋在生产与贮藏中存在着醋体颜色加深,返混等现象,为了提高酿造柿子醋的澄清度,减少柿子醋中沉淀物的含量,使用生产上常用的几种澄清剂对柿子醋澄清效果进行研究,结果表明,壳聚糖、PVPP、皂土对柿子醋的澄清均有不同程度的影响,其最优配方组合为:壳聚糖用量1.5g/L,PVPP用量1.2g/L,皂土用量0.5g/L。

关键词：柿子醋壳聚糖 PVPP 皂土

船舶航向跟踪系统自适应滤波反步终端滑模控制

在线全文

学校读者我要写书评

暂无评论

北京理工大学学报 2015年第2期35卷 180-185页

作者：夏国清武慧勇赵昂王元慧哈尔滨工程大学自动化学院黑龙江哈尔滨150001

针对船舶航向非线性系统,提出了一种基于自适应滤波反步法的终端滑模控制器.系统由二阶非线性野本模型和舵机响应模型串联组成,考虑了模型不确定性和外部干扰等未知项,并由模糊系统对未知项进行在线逼近.首先引入二阶低通滤波器,避免了... 详细信息

针对船舶航向非线性系统,提出了一种基于自适应滤波反步法的终端滑模控制器.系统由二阶非线性野本模型和舵机响应模型串联组成,考虑了模型不确定性和外部干扰等未知项,并由模糊系统对未知项进行在线逼近.首先引入二阶低通滤波器,避免了对虚拟控制律的解析求导,从而简化了反步控制器的设计,而且滤波器的低通特性可大大减小测量噪声的影响;然后利用滤波反步法的结果设计了终端滑模面,并最终得到了使系统跟踪误差有限时间收敛的终端滑模控制器.根据Lyapunov理论证明了闭环系统所有误差变量均是一致最终有界的.仿真结果验证了所提方法的有效性.

关键词：船舶航向跟踪自适应滤波反步法终端滑模模糊系统