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MECHANISM FOR DIFFUSION OF BORON IN γ-Fe

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Acta Metallurgica Sinica(English Letters) 1992年第5期5卷 318-323页

作者： YU Zongsen CHEN Ning university of science and Technology beijing,beijing,china beijing Univ of science and Technology Beijing China

Mechanism for diffusion of B in γ-Fe is believed to be mainly by means of boron-vacancy complexes other than as interstitial atoms *** was made of calculation on the ba- sis of theoretical model proposed by the *** calculated diffusion coefficient of B in γ-Fe after this mechanism is consistent with the experimental *** addition,this is also supported by the non-equilibrium segregation phenomenon of B at grain boundaries of γ-Fe and the lattice constant measurement of Fe-B alloy.

关键词： boron vacancy diffusion non-equilibrium segregation γ-Fe

AODV routing overhead analysis based on link failure probability in MANET

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The Journal of china Universities of Posts and telecommunications 2010年第5期17卷 109-115页

作者： ZHANG Qin-juan,WU Mu-qing,ZHEN Yan,SHANG Cui-li School of Telecommunication Engineering,beijing university of Posts and telecommunications,beijing 100876,china [a] School of Telecommunication Engineering Beijing University of Posts telecommunications Beijing 100876 China

This article puts forward an Ad-hoc on-demand distance vector routing （AODV） routing overhead analysis method in mobile Ad-hoc network （MANET）.although multiple routing protocols have been proposed to improve the performance,scarcely any paper analyzed the routing overhead caused by routing setup and maintenance processes in mathematical *** overhead consumes part of network resources and limits the supported traffic in the *** on-demand routing protocols like AODV,the routing overhead depends on the link failure probability to a great *** article analyzes the collision probability caused by hidden-node problem and the impact on link failure *** chain and rectangle scenarios,it presents a mathematical analysis of the theoretical routing overhead of AODV protocol based on link failure *** on OPNET 14.5 platform match well with the theoretical derivation which confirms the effectiveness of the analysis method.

关键词： MANET saturate throughput AODV routing overhead

On-demand coding-aware routing in wireless Mesh networks

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The Journal of china Universities of Posts and telecommunications 2010年第5期17卷 80-86,92页

作者： SUN Jian-zhen,LIU Yuan-an,HU He-fei,YUAN Dong-ming Wireless Communications and EMC Laboratory,beijing university of Posts and telecommunications,beijing 100876,china [a] Wireless Communications EMC Laboratory Beijing University of Posts telecommunications Beijing 100876 China

Network coding,which exploits the broadcast nature of wireless medium,is an effective way to improve network performance in wireless multi-hop networks,but the first practical wireless network coding system COPE cannot actively detect a route with more coding opportunities and limit the coding structure within two-hop *** on-demand coding-aware routing scheme （OCAR） for wireless Mesh networks is proposed to overcome the limitations specified above by actively detecting a route with more coding opportunities along the entire route rather than within two-hop *** more coding opportunities tends to route multiple flows ‘close to each other’ while avoiding interference requires routing multiple flows ‘away from each other’.OCAR achieves a tradeoff by adopting RC AIA as routing metric in route discovery,which is not only coding-aware but also considers both inter and intra flow *** results show that,compared with Ad-hoc on-demand distance vecfor routing （AODV） and AODV＋COPE,OCAR can find more coding opportunities,thus effectively increase network throughput,reduce end to end delay and alleviate network congestion.

关键词： Mesh networks network coding coding-aware routing protocol

Nonlinear Theory on Dynamic Controlling Interface Patterns DuringSolidification of a Dilute Binary alloy

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International Journal of Minerals,Metallurgy and Materials 1999年第4期13卷 253-258页

作者： Zidong Wang Hanqi Hu(Material science and Engineering School, university of science and Technology beijing, beijing 100083. china) Material science and Engineering School University of Science and Technology Beijing Beijing 100083 China

In non-equilibrium nonlinear region, the nonlinear equations of time dependence of perturbation amplitude at the solid/liquidinterface during solidification of a dilute binary alloy are established on the base of assuming that there is local equilibrium at the solid/liquid interface and considering that curvature, temperature and composition at the solid/liquid interface which are related to the perturbation amplitude are nonlinear. As a result, patterns at the solid/liquid interface during solidification process, which is from nonsteadystate to steady state can be controlled by these nonlinear equations.

关键词： nonlinearity solidification, dilute binary alloy, dynamic control

Modified chaotic ant swarm to function optimization

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The Journal of china Universities of Posts and telecommunications 2009年第1期16卷 58-63页

作者： LI Yu-ying , WEN Qiao-yan, LI Li-xiang State Key Laboratory of Networking and Switching Technology, beijing university of Posts and telecommunications,{3., china [a]State Key Laboratory of Networking and Switching Technology beijing university of Posts and telecommunications beijing 100876 china

The chaotic ant swarm algorithm （CAS） is an optimization algorithm based on swarm intelligence theory, and it is inspired by the chaotic and self-organizing behavior of the ants in nature. Based on the analysis of the properties of the CAS, this article proposes a variation on the CAS called the modified chaotic ant swarm （MCAS）, which employs two novel strategies to significantly improve the performance of the original algorithm. This is achieved by restricting the variables to search ranges and making the global best ant to learn from different ants＇ best information in the end. The simulation of the MCAS on five benchmark functions shows that the MCAS improves the precision of the solution.

关键词： chaotic ant swarm benchmark functions modified chaotic ant swarm swarm intelligence

Automatic composition of information-providing web services based on query rewriting

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science china(Information sciences) 2012年第11期55卷 2428-2444页

作者： ZHAO WenFeng,LIU ChuanChang & CHEN JunLiang State Key Laboratory of Networking and Switching Technology,beijing university of Posts and telecommunications,beijing 100876,china 1. State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing 100876 China

Compared with normal web services,information-providing services have unique features that have seldom been considered in existing research on the automatic composition of web *** this paper,we present a simple,yet well-formed,semantic-based capability model for information-providing web services,which can express such features as not modifying the world state and not requiring all input/output parameters to be supplemented with class information as *** then present a corresponding automatic composition method derived from a query rewriting algorithm,MiniCon,used in the data integration *** method adequately utilizes previous features,enables primitive semantic reasoning,and can generate executable BPEL scripts *** of the method is complementary to traditional search-based *** on a typical type of problem show that the method is usable in practice.

关键词： web services automatic composition query rewriting data integration ontology semantic web

Bursting of Morris-Lecar neuronal model with current-feedback control

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science china(Technological sciences) 2009年第3期52卷 771-781页

作者： DUAN LiXia1, LU QiShao2 & CHENG DaiZhan3.1 College of science, North china university of Technology, {3. 100144, china 2 School of science, {3. university of Aeronautics and Astronautics, {3. 100191, china 3.Institute of Systems science, Chinese Academy of sciences, {3. 100190, china College of science North China University of Technology Beijing 100144 China School of science Beijing University of Aeronautics and Astronautics Beijing 100191 China Institute of Systems science Chinese Academy of Sciences Beijing 100190 China

The Morris-Lecar (ML) neuronal model with current-feedback control is considered as a typical fast-slow dynamical system to study the combined influences of the reversal potential VCa of Ca2+ and the feedback current I on the generation and transition of different bursting oscillations. Two-parameter bifurcation analysis of the fast subsystem is performed in the parameter (I, VCa)-plane at first. Three important codimension-2 bifurcation points and some codimension-1 bifurcation curves are obtained which enable one to determine the parameter regions for different types of bursting. Next, we further divide the control parameter (V0, VCa)-plane into five different bursting regions, namely, the "fold/fold" bursting region R1, the "fold/Hopf" bursting region R2, the "fold/homoclinic" bursting region R3. the "subHopf/homoclinic" bursting region R4 and the "subHopf/subHopf" bursting region R5, as well as a silence region R6. Codimension-1 and -2 bifurcations are responsible for explanation of transition mechanisms between different types of bursting. The results are instructive for further understanding the dynamical behavior and mechanisms of complex firing activities and information processing in biological nervous systems.

关键词： neuron bursting bifurcation fast-slow dynamics analysis codimension

Solutions of Minimal Period for An Extended Hamiltonian System

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The Journal of china Universities of Posts and telecommunications 2002年第3期9卷 23-27,37页

作者： LIU Bao-sheng (School of science, beijing university of Posts and {3., beijing 100876, P.R.china) School of science Beijing University of Posts and Telecommunications Beijing 100876 P.R.China

Solutions of minimal period for the Hamiltonian system =JH′(x) has been proven under the conditionas H″(x) -1 →0 as |x|→∞ and H(x) is of higher order than 2 in the neighborhood of the origin; In this paper, w... 详细信息

关键词： hamiltonian system morse index minimal period solution

Recycling of Spent Nickel-Cadmium Batteries

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International Journal of Minerals,Metallurgy and Materials 2000年第2期14卷 126-131页

作者： Xanghua Kong Pingnan Wu(Metallurgy School, university of science and Technology {3., {3. 100083. china) Metallurgy School University of Science and Technology Beijing Beijing 100083 China

A technique for recycling spent nickel-cadmium batteries, which makes separaion of cadmium and nickel possible, is developed by laboratory-scale experiments. NH3.H2CO3.aqueous solution was used in this leaching technique. Since neutralization and/or solvent extraction were not required in the separation procedure of nickel and cadmium, the closed systemizaion of the process becomespossible. Experimental results show that, (1) if the NH3.concentraion of leaching solution is sufficiently high and the ratio of H2CO3.toNH3.is properly adjusted, both Ni(OH)2 and Cd(OH)2 react with NH, and quickly dissolve into leaching solution, and (2) Ni(OH)2 can beconverted into insoluble NiO by calcination at 500℃, and CdO from Cd(OH)2 by calcination maintains good solubility in NH3.H2CO3.queous solution. As a conclusion, the recycling technique characterized by two step leaching can be developed based on such changesin dissolution behavior by calcination. Meanwhile, the yields of 99.8% for nickel and 97.6% for cadmium are obtained, and the puritiesof Recycling of Spent Nickel-Cadmium BatterieRecycling of Spent Nickel-Cadmium Batteries Recycling of Spent Nickel-Cadmium Batteriesrecovered nickel and cadmium are 99.9% and 98.6%, respectively.

关键词： nickel-cadmium batteries recycling, ammonia leaching closed system environmental protection