检索结果-南通市图书馆

SOME SYNCHRONIZATION CRITERIA FOR GENERAL COMPLEX NETWORKS WITH COUPLING DELAYS

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2011年第6期24卷 1057-1067页

作者： huan pan Xiaohong NIAN Weihua GUI School of Information Science and Engineering Central South University Changsha 410004 China

A general complex delayed dynamical network model with asymmetric coupling matrix is considered in this paper. For reducing the conservativeness of synchronization criteria, several novel synchronization stability conditions are presented by using delay decomposition methods. Numerical examples which are widely used to study delay-dependent synchronization stability are given to illustrate the effectiveness of the proposed methods.

关键词： Asymmetric coupling complex network linear matrix inequality synchronization timedelay.

Leader-following consensus of multi-agent systems with switching topologies and time-delays

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

控制理论与应用（英文版） 2013年第2期11卷 306-310页

作者： Ling GUO Xiaohong NIAN huan pan School of Information Science and Engineering Central South University

This paper investigates the leader-following consensus problem of multi-agent systems where the leader is static and the controlling effect of each follower depends on its own state. The control protocols are proposed for two cases： i） for network with switching topologies and undirected information flow; ii） for network with directed information flow and communication time-delays. With the aid of several tools from algebraic graph, matrix theory and stability the- ory, the sufficient conditions guaranteeing leader-following consensus are obtained by constructing appropriate Lyapunov functions. Simulations are presented to demonstrate the effectiveness of our theoretical results.

关键词： Leader-following consensus Multi-agent systems Switching topology Time-delays

Trajectory tracking and formation control based on consensus in high-dimensional multi-agent systems

在线全文

学校读者我要写书评

暂无评论

High Technology Letters 2012年第3期18卷 326-332页

作者： Su Saijun Nian Xiaohong pan huan School of Information Science and Engineering Central South University Changsha 410083 P. R. China

This paper discusses consensus problems for high-dimensional networked multi-agent systems with fixed topology. The communication topology of multi-agent systems is represented by a digraph. A new consensus protocol is proposed, and consensus convergence of multigent systems is analyzed based on the Lyapunov stability theory. The consensus problem can be formulated into solving a feasible problem with bilinear matrix inequality （BMI） constrains. Furthermore, the consensus protocol is extended to achieving tracking and formation control. By introducing the formation structure set, each agent can gain its individual desired trajectory. Finally, numerical simulations are provided to show the effectiveness of our strategies. The results show that agents from arbitrary initial states can asymptotically reach a consensus. In addition, agents with high-dimensional can track any target trajectory, and maintain desired formation during movement by selecting appropriate structure set.

关键词： consensus protocol multi-agent systems fixed topology trajectory tracking for-mation control

Analysis and compensation of the reflector antenna pointing error under wind disturbance

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

Research in Astronomy and Astrophysics 2021年第6期21卷 387-396页

作者： Qian Xu Jie Zhang Zhao-Yu Wang huan-Zhi pan Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China Key Laboratory of Chinese Academy of Sciences for Radio Astronomy Urumqi 830011China Xidian University Key Laboratory of Electronic Equipment Structure DesignMinistry of EducationXi’an 710071China

A large reflector antenna has been widely used in satellite communications,gravitational wave detection,galaxy origin observation and other fields due to its narrow beam and high *** the increase of the antenna aperture and the improvement of the working frequency,the requirements for the pointing accuracy of an antenna are also ***,the effect of environmental load on the deformation of the antenna structure,which in turn affects its beam pointing,has become a key problem to be solved urgently in the antenna engineering *** key issue to solving this problem involves accurately estimating the pointing error caused by the structural deformation and designing an effective controller that is based on the structural *** this paper,we first establish a dynamic model for antenna structure based on the modal superposition *** model is then modified by using modal characteristics and the dynamic displacement information of the sampling points to achieve the purpose of accurately estimating the structural ***,by considering the influence of the deformation of the rotating shaft and the reflector surface on the pointing accuracy,a control-oriented pointing error analysis model is established for estimating the pointing error caused by the environmental load in real ***,based on considering the influence of the shaft deformation on the error compensation,the feedback error amount is decoupled and corrected to improve the accuracy of the compensation ***,this paper analyzes and verifies the 65 m S/X-band dual reflector antenna with a numerical *** consider a fluctuating wind with an average wind speed of 10 m s^(-1) as an example,which results in a maximum pointing error of 55.82″as calculated by the antenna theoretical model,whereas the maximum pointing error as predicted by our model is 68.27″.The pointing error after compensating for the cause of the environmental load with the modified

关键词： telescopes methods:analytical methods:numerical

Lesion discrimination with breath-hold hepatic diffusionweighted imaging:A meta-analysis

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2015年第5期21卷 1621-1627页

作者： Zhi-Guang Chen Li Xu Si-Wei Zhang Yan huang Rui-huan pan Department of Radiology Guangdong Provincial Traditional Chinese Medicine Hospital Department of Neurology Guangdong Provincial Traditional Chinese Medicine Hospital

AIM:To investigate the diagnostic capability of breathhold diffusion-weighted imaging(DWI) for differentiation between malignant and benign hepatic ***:A total of 614 malignant liver lesions(132 hepatocellular carcinomas,468 metastases and 14 intrahepatic cholangiocarcinomas) and 291 benign liver lesions(102 hemangiomas,158 cysts,24 focal nodular hyperplasia,1 angiomyolipoma and 6 hepatic adenomas) were included from seven studies(eight sets of data).RESULTS:The pooled sensitivity and specificity of breath-hold DWI were 0.93 [95% confidence interval(CI):0.91-0.95] and 0.87(95%CI:0.83-0.91),*** positive likelihood ratio and negative likelihood ratio were 7.28(95%CI:4.51-11.76) and 0.09(95%CI:0.05-0.17),*** P value for χ2 heterogeneity for all pooled estimates was 0.05).CONCLUSION:Breath-hold DWI is useful for differentiating between malignant and benign hepatic *** diffusion characteristics of benign lesions that mimic malignant ones have rarely been investigated.

关键词： Breath-hold imaging Diffusion-weighted imaging Hep

Particle concentration effect in adsorption/desorption of Zn(Ⅱ) on anatase type nano TiO_2

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

Journal of Environmental Sciences 2007年第12期19卷 1442-1445页

作者： YANG Yu-huan CHEN Hao pan Gang State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China.

Adsorption/desorption in a new Zn（Ⅱ）-TiO2 adsorption system was investigated at different particle concentrations （Cp）. TEM, SEM and XRD analyses revealed that the TiO2 particles were an aggregation of nano-sized （approximately 10 nm） pure anatase-type TiO2. Adsorption experiments were carried out with particle concentrations of 100, 400 and 1000 mg/L, and their adsorption isotherms were found to decline successively, showing an obvious Cp effect. Desorption experiments indicated that adsorption in this system was irreversible, and the irreversibility increased with increasing Cp. These phenomena could be explained by the MEA （metastable equilibrium adsorption） theory and the Cp effect could be modeled well with an MEA-Freundlich-type Cp effect isotherm equation. This study may heln understand environmental behavior of contaminants on ultrafine natural particles.

关键词： Zn(Ⅱ) anatase-type Ti02 particle concentrations effect adsorption desorption

Synchronization in Dynamic Networks with Time-varying Delay Coupling Based on Linear Feedback Controllers

在线全文

学校读者我要写书评

暂无评论

自动化学报 2010年第12期36卷 1766-1772页

作者： pan huan NIAN Xiao-Hong GUI Wei-Hua School of Information Science and Engineering Central South UniversityChangsha 410075P.R.China

This paper focuses on the synchronization problems of general complex dynamical networks with time-varying *** cases of the time-varying delay are considered — one being continuous-uniformly bounded and the other being differentiable-uniformly bounded with the *** the coupling configuration matrix is also assumed to be asymmetric and *** new delay-dependent synchronization criteria are derived and a strategy for synchronization is presented based on a method of linear state feedback *** bounds of controller are solved by *** examples are given to illustrate the effectiveness of the proposed synchronization criteria

关键词：自动化线性系统自动模拟理论

Close Relationship between the 2009 H1N1 Virus and South Dakota AIV Strains

在线全文

学校读者我要写书评

暂无评论

Virologica Sinica 2011年第1期26卷 54-60页

作者： Cun Li Xiao-ping An Zhi-qiang Mi Da-bin Liu huan-huan Jiang Bo pan Sheng Wang Bin Chen Yi-gang Tong State Key Laboratory of Pathogen and Biosecurity Beijing Institute of Microbiology and Epidemiology Beijing 100071 China

Although previous publications suggest the 2009 pandemic influenza A (H1N1) virus was reassorted from swine viruses of North America and Eurasia,the immediate ancestry still remains elusive due to the big evolutionary distance between the 2009 H1N1 virus and the previously isolated strains. Since the unveiling of the 2009 H1N1 influenza,great deal of interest has been drawn to influenza,consequently a large number of influenza virus sequences have been deposited into the public sequence databases. Blast analysis demonstrated that the recently submitted 2007 South Dakota avian influenza virus strains and other North American avian strains contained genetic segments very closely related to the 2009 H1N1 virus,which suggests these avian influenza viruses are very close relatives of the 2009 H1N1 virus. Phylogenetic analyses also indicate that the 2009 H1N1 viruses are associated with both avian and swine influenza viruses circulating in North America. Since the migrating wild birds are preferable to pigs as the carrier to spread the influenza viruses across vast distances,it is very likely that birds played an important role in the inter-continental evolution of the 2009 H1N1 virus. It is essential to understand the evolutionary route of the emerging influenza virus in order to find a way to prevent further emerging cases. This study suggests the close relationship between 2009 pandemic virus and the North America avian viruses and underscores enhanced surveillance of influenza in birds for understanding the evolution of the 2009 pandemic influenza.

关键词： 2009 influenza A (H1N1) virus Evolution Avian influenza virus (AIV)

Antioxidative Effect of Luteolin Pretreatment on Simulated Ischemia/Reperfusion Injury in Cardiomyocyte and Perfused Rat Heart

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Integrative Medicine 2017年第7期23卷 518-527页

作者： ZHANG Rui-qu LI Dong-ye XU Tong-da ZHU Sha-sha pan huan-jun FANG Fang WU Xin SUN Hong Institute of Cardiovascular Disease Research Xuzhou Medical College Xuzhou Jiangsu Province 221002 China Department of Physiology Xuzhou Medical College XuzhouJiangsu Province 221002 China

Objective：To investigate the antioxidative effect and mechanism of luteolin on rat cardiomyocytes and isolated hearts fol owed by simulated ischemia/reperfusion（SI/R） injury. Methods：The left ventricular cardiomyocytes and the isolated hearts from adult rats were subjected to SI/R injury. The experiment groups included control, SI/R, luteolin ＋ SI/R（Lut ＋ SI/R）, vitamin E（Vit E）＋ SI/R, and LY294002 ＋ luteolin ＋ SI/R（LY ＋ Lut ＋ SI/R） groups. Cell viability, shortening amplitude, lactate dehydrogenase（LDH） release, superoxide dismutase（SOD） activity, the production of reactive oxygen species（ROS） and malondialdehyde（MDA）, expression levels of Akt, phosphorylated Akt, NOX2（gp91phox）, NOX2 m RNA, mitogen-activated protein kinase（p38 MAPK） and phosphorylated p38 MAPK were al measured after 3-h simulated ischemia and 2-h simulated reperfusion procedure in cardiomyocytes. Vit E was used as a standard control. The contractile function of isolated hearts was further observed after they were subjected to 30-min global ischemia and 120-min reperfusion. Results：Pretreatment with 8-μmol/L luteolin substantially increased cel viability and shortening amplitude, while reducing evidence of oxidative stress-induced damage in the cel s. In addition, the expression of NOX2, NOX2 m RNA and phosphorylation of p38 MAPK were al downregulated. Furthermore, pretreatment with 40-μmol/L luteolin improved the recovery of myocardial contractile function fol owing SI/R-induced injury, and luteolin markedly increased phosphorylation of Akt. However, all of the above effects were partially inhibited by the phosphatidylinositol 3-kinase（PI3K） inhibitor, LY294002. Conclusions：Luteolin prevents SI/R-induced myocardial damage by reducing oxidative stress-induced injury in isolated rat hearts and cardiomyocytes, and the cardioprotection induced by luteolin was partial y mediated by the PI3K/Akt pathway.

关键词： luteolin cardiomyocyte ischemia/reperfusion cardioprotection