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Prediction method for October 2003 solar storm

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science china(Technological sciences) 2006年第5期49卷 629-640页

作者： XIE Yanqiong1, 2, 3, WEI Fengsi1, FENG Xueshang1 & ZHONG Dingkun1, 2 1. State Key Laboratory of Space Weather, center for Space science and Applied research, Chinese Academy of sciences, Beijing 100080, china 2. Graduate school, Chinese Academy of sciences, Beijing 100039, china 3. Institute of Meteorology, pla university of science and technology, nanjing 211101, china State Key Laboratory of Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences Beijing China Graduate school Chinese Academy of Sciences Beijing China Institute of Meteorology PLA University of Science and Technology Nanjing China

Aiming at two intense shock events on October 28 and 29, 2003, this paper presents a two-step method, which combines synoptic analysis of space weather ——“observing” and quantitative prediction ——“palpating”, and then uses it to test predictions. In the first step of “observing”, on the basis of observations of the solar source surface magnetic field, interplanetary scintillation (IPS) and ACE spacecraft, we find that the propagation of the shocks is asymmetric relative to the normal direction of their solar sources, and the Earth is located near the direction of the fastest speed and the greatest energy of the shocks. As the two fast ejection shock events, the fast explosion of coronal mass of the extremely high temperature, the strong magnetic field, and the high speed background solar wind are also helpful to their rapid propagation. In the second step of “palpating”, we adopt a new membership function of the fast shock events for the ISF method. The predicted results show that for the onset time of the geomagnetic disturbance, the relative errors between the observational and the predicted results are 1.8% and 6.7%; and for the magnetic disturbance magnitude, the relative errors are 4.1% and 3.1%, re- spectively. Furthermore, the comparison among the predicted results of our two-step method with those of five other prevailing methods shows that the two-step method is advantageous. The results tell us that understanding the physical features of shock propagation thoroughly is of great importance in improving the prediction precision.

关键词： solar storm, interplanetary shock, interplanetary scintillation, two-step method, ISF method.

Degradation of nitrobenzene in wastewater by γ-ray irradiation

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Journal of Environmental sciences 2004年第3期16卷 364-366页

作者： ZHANG Shu juan 1, FENG Shao hong 1, YU Han qing 1,* , LI Qian rong 2 (1 Department of Chemistry, university of science & technology of china, Hefei 230026, china. 2 research center for Physics & Chemistry, university of science & technology of china, Hefei 230026, china) Department of Chemistry University of Science & Technology of China Hefei 230026 China research center for Physics & Chemistry University of Science & Technology of China Hefei 230026 China

The degradation of nitrobenzene(NB) by γ ray irradiation was studied. The influences of dose rate and initial NB concentration were investigated in details. At a dose rate of 55 Gy/min, the degradation kinetics was pseudo first order at NB concentrations from 0 2 mmol/L to 4 0 mmol/L. At an initial NB concentration of 0 8 mmol/L, the degradation of NB at various dose rates also followed pseudo first order kinetics. Dissolved oxygen was found to have a positive effect on NB degradation. The degradation products were identified as nitrophenol, nitrosobenzene, and hydroquinone, and so on. Based on the product analysis, possible degradation pathways of nitrobenzene were proposed.

关键词： degradation irradiation nitrobenzene(NB) kinetics

Preparation of Compound Ultrafine CeO2 by Wet-Solid-Phase Mechanochemical Modification

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Journal of Rare Earths 2004年第Z1期22卷 42-45页

作者： Gu Ziyin Chen Weifan（china National Special Superfine Powder Engineering research center, nanjing university of science & technology, nanjing 10094, china） Hu Pinggui Li Yongxiu Engineering research center for Rare Earth Nanchang UniversityNanchang 330047 China 　　 Engineering Research Center for Rare Earth Nanchang UniversityNanchang 330047 China Engineering Research Center for Rare Earth Nanchang UniversityNanchang 330047 China

To satisfy practical requirements from industrial applications, an alternate route for synthesis compound ultrafine CeO2 powders by wet-solid-phase mechanochemical modification using industrial grade hydrated cerium carbonate as raw material was *** effect of modifier reaction percentage, reaction time, calcining temperature and modifier amount on particle size, density, suspensibility, and hardness of compound CeO2 powder was *** phase evolutions of preparation process were characterized by *** micrograph of the final product shows that compound CeO2 powders obtained are well-dispersed, spherically-shaped, uniformly-sized and submicron-sized *** method is readily available in raw material, low in cost, simple in process, and has great potential for *** compound CeO2 powders of different physical properties can be synthesized by controlling the above-mentioned influence factors in preparation process.

关键词： ultrafine compound CeO2 powder mechanochemical modification preparation rare earths

Representations of Real and Complex Stability Radii of 2-Dimensional LinearSystems

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International Journal of Minerals,Metallurgy and Materials 1999年第4期13卷 299-301页

作者： Lequan Min1.2 Ning Song1(l Applied science school, university of science and technology’ Beijing, Beijing 100083, china2 china center of Advanced science and technology, Beijing 100080, china) Applied science school University of Science and Technology Beijing Beijing 100083 China china center of Advanced science and technology Beijing 100080 China

Rigorous proofs are given for the representations of real and complex stability' radii of 2-dimensional linear systems. This representations can be used to analyze the robustness of a nominal 2-dimensional linear system under pelturbation of the system parameters, in particular testing the effect of numerical algorithms which are used to calculate the real stability radii of higher dimensional piecewise-linear systems.

关键词： linear systems robustness stability radii

A relative local variational principle for topological pressure

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science china Mathematics 2010年第6期53卷 1491-1506页

作者： MA XianFeng1,CHEN ErCai2,3,& ZHANG AiHua2,4 1Department of Mathematics,East china university of science and technology,Shanghai 200237,china 2school of Mathematics and Computer science,nanjing Normal university,nanjing 210097,china 3center of Nonlinear science,nanjing university,nanjing 210093,china 4College of Mathematics and Physics,nanjing university of Posts and Telecommunications,nanjing 210046,china Department of Mathematics East China University of Science and Technology Shanghai China school of Mathematics and Computer science Nanjing Normal University Nanjing China center of Nonlinear science Nanjing University Nanjing China College of Mathematics and Physics Nanjing University of Posts and Telecommunications Nanjing China

We define the relative local topological pressure for any given factor map and open cover,and prove the relative local variational principle of this *** precisely,for a given factor map π:(X,T)→(Y,S) between two topological dynamical systems,an open cover U of X,a continuous,real-valued function f on X and an S-invariant measure ν on Y,we show that the corresponding relative local pressure P(T,f,U,y) satisfies sup μ∈M(X,T){ hμ(T,U|Y)+∫X f(x)dμ(x) :πμ=ν}=∫Y P(T,f,U,y)dν(y),where M(X,T) denotes the family of all T-invariant measures on ***,the supremum can be attained by a T-invariant measure.

关键词： pressure conditional entropy relative local variational principle

Stabilization for discrete-time fuzzy systems with Takagi-Sugeno's models:reduce the complexity

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science china(Information sciences) 2010年第12期53卷 2506-2513页

作者： WANG LiKui 1 & LIU XiaoDong 2 1 school of Mathematics and Information science,Nanchang Hangkong university,Nanchang 330063,china 2 research center of Information and Control,Dalian university of technology,Dalian 116024,china school of Mathematics and Information science Nanchang Hangkong University Nanchang China research center of Information and Control Dalian University of Technology Dalian China

The problem of sate feedback control for discrete-time fuzzy systems with Takagi-Sugeno's models is investigated to reduce the computational burden.A stabilization condition is obtained by applying a new Lyapunov *** is shown that our new theorem is equivalent to an existing result in guaranteeing the stability of the fuzzy system but consumes less computational time than the *** effectiveness and the superiority of the proposed design approach are demonstrated by an example borrowed from the literature.

关键词： Takagi-Sugeno’s fuzzy model non-quadratic Lyapunov function linear matrix inequality

Study on rare earth/alkaline earth oxide-doped CeO_2 solid electrolyte

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Rare Metals 2007年第4期26卷 311-316页

作者： YAN Kai ZHEN Qiang Song Xiwen school of Materials science and Engineering Shanghai University Shanghai 200072 China research center of Nanoscience and Nanotechnology Shanghai Univeesity Shanghai 200444 China school of Materials science and Engineering Inner Mongolia University of Science and Technology B aotou 014010 China

Five types of rare earth/alkaline earth oxide-doped CeO2 superfine-powders were synthesized by a low-temperature combustion technique. The relevant solid electrolyte materials were also sintered by pressureless sintering at different temperatures. The results of X-ray diffraction and transmission electron microscopy showed that the grain size of the powders was approximately 20-30 nm, and rare earth/alkaline earth oxides were completely dissolved into ceria-based solid solution with fluorite structure. The electrical conductivities of the SmzO3-CeO2 system were measured by the ac impedance technique in air at temperatures ranging from 513-900℃. The results indicated that the ionic conductivities of Srno.2oCe0.8Ol.875 solid electrolyte increase with increasing sintering temperature, and the relationship between the conductivities and measuring temperature obeys the An＇henius equation. Then the SmzO3-CeO2 material was further doped with other rare earth/alkaline earth oxide, and the conductivities improve with the effective index.

关键词： doped ceria rare earth/alkaline earth oxide solid electrolyte conductivity effective index

基流对热对流涡旋结构影响的实验结果初步分析

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物理学报 2002年第9期51卷 2057-2062页

作者：林上金解放军理工大学南京211101

用实验室模拟方法研究了径向温度梯度对热对流涡旋的影响 ,结果表明 ,径向温度梯度所引起的基流使热对流涡旋的对称性结构被破坏 ,使涡旋变成非对称结构 ,并使涡旋向基流下游偏移 ,其强度随基流的加强而减弱 ,直至消失 .热对流涡旋越强... 详细信息

用实验室模拟方法研究了径向温度梯度对热对流涡旋的影响 ,结果表明 ,径向温度梯度所引起的基流使热对流涡旋的对称性结构被破坏 ,使涡旋变成非对称结构 ,并使涡旋向基流下游偏移 ,其强度随基流的加强而减弱 ,直至消失 .热对流涡旋越强其对称性结构越稳定。

关键词：转盘实验基流热对流涡旋径向温度梯度对称性结构天然系统

P2P traffic optimization

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science china(Information sciences) 2012年第7期55卷 1475-1492页

作者： ZHANG GuoQiang 1,2 ,TANG MingDong 3 ,CHENG SuQi 2,4 ,ZHANG GuoQing 2 ,SONG HaiBin 5 ,CAO JiGuang 6 & YANG Jing 7 1 school of Computer science and technology,nanjing Normal university,nanjing 210046,china 2 Institute of Computing technology,Chinese Academy of sciences,Beijing 100190,china 3 school of Computer science and Engineering,Hunan university of science and technology,Xiangtan 411201,china 4 Graduate university of Chinese Academy of sciences,Beijing 100190,china 5 nanjing R&D center,Huawei Technologies,nanjing 210012,china 6 china Academy of Telecommunication research of MIIT,Beijing 100191,china 7 china Mobile research Institute,Beijing 100053,china school of Computer science and technology Nanjing Normal University Nanjing China Institute of Computing technology Chinese Academy of Sciences Beijing China school of Computer science and Engineering Hunan University of Science and Technology Xiangtan China Graduate university of Chinese Academy of sciences Beijing China nanjing R&D center Huawei Technologies Nanjing China china Academy of Telecommunication research of MIIT Beijing China china Mobile research Institute Beijing China

Peer-to-peer (P2P) based content distribution systems have emerged as the main form for content distribution on the Internet,which can greatly reduce the distribution cost of content providers and improve the overall system ***,the mismatch between the overlay and underlay networks causes large volume of redundant traffic,which intensifies the tension between P2P content providers and ***,how to efficiently use network resources to reduce the traffic burden on the ISPs is crucial for the sustainable development of P2P *** paper surveys the state-of-art P2P traffic optimization technologies from three perspectives:P2P cache,locality-awareness and data *** details,comparison between these technologies and their applicabilities are presented,followed by a discussion of the issues that remain to be addressed and the direction of future content distribution research.

关键词： P2P traffic localization P2P traffic optimization P2P cache locality-awareness network coding content-centric network