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Interference aware routing for mobile ad hoc networks based on node's sending and receiving capabilities

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The Journal of China Universities of Posts and Telecommunications 2013年第4期20卷 73-79,111页

作者： GU Chao zhu qi Jiangsu Key Laboratory of Wireless Communications Nanjing University of Posts and Telecommunications Key Lab on Wideband Wireless Communications and Sensor Network Technology of Ministry of Education Nanjing University of Posts and Telecommunications

How to efficiently build routes among nodes is increasing important for mobile ad hoc networks （MANETs）. This paper puts forward an interference aware routing protocol called Interference aware cross layer routing protocol （IA-CLR） for MANETs based on the IEEE 802.11 medium access layer （MAC）. By defining the node＇s sending and receiving capabilities, IA-CLR can indicate the interference strength of the link in a real and comprehensive way. Further more, in order to choose the route with minimum bottleneck link interference, a new routing metric is proposed by combining the MAC layer and the network layer for cross layer design. Simulation results show that IA-CLR can significantly improve the performances of network such as the average end-to-end delay, the packets loss ratio and the throughput.

关键词： ad hoc networks routing protocol routing design interference aware

Kernel semi-supervised graph embedding model for multimodal and mixmodal data

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Science China(Information Sciences) 2020年第1期63卷 247-249页

作者： qi ZHANG rui LI Tianguang CHU School of Information Technology & Management University of International Business & Economics Key Laboratory of Machine Perception(Ministry of Education) Peking University School of Mathematical Sciences Dalian University of Technology State Key Laboratory for Turbulence and Complex Systems College of Engineering Peking University

Dear editor,Semi-supervised learning has obtained increasing interests in machine learning, because making use of both labeled and unlabeled training samples helps extracting discriminative features and meanwhile reduces the time-consuming and labor-intensive labeling burden. For extracting features upon multimodal (i.e., data of the same

关键词： Kernel semi-supervised graph embedding model for multimodal and mixmodal data

Maximum modulus principle estimates for one dimensional fractional diffusion equation

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Applied Mathematics(A Journal of Chinese Universities) 2015年第4期30卷 466-478页

作者： zhu Lin rui Hong-xing School of Mathematics and Computer Science Ningxia University School of Mathematics Shandong University

We present scheme I for solving one-dimensional fractional diffusion equation with variable coefficients based on the maximum modulus principle and two Grunwald approxima- tions. Scheme II is obtained by using classic Crank-Nicolson approximations in order to improve the time convergence. Schemes are proved to be unconditionally stable and second-order accuracy in spatial grid size for the problem with order of fractional derivative belonging to [（√17- 1）/2, 2] using the maximum modulus principle. A numerical example is given to confirm the theoretical analysis result.

关键词： the maximum modulus principle the Griinwald approximation finite difference scheme frac-tional diffusion equation numerical analysis.

Recent advances of nanoporous metal-based catalyst: synthesis, application and perspectives

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Journal of Iron and Steel Research International 2019年第8期26卷 779-795页

作者： rui-qi Yao Xing-you Lang qing Jiang Key Laboratory of Automobile Materials (Ministry of Education) School of Materials Science and Engineering Jilin University Changchun 130022 Jilin China

Nanoporous metal-based catalysts with the specific bicontinuous interconnected ligaments/pores network exhibit highly active performances in application for energy conversion, which represent a broader trend in the design of catalyst materials. These promising nanomaterials commendably provide highly conductive porous morphologies with reduced contact resistances, large electrochemical surface areas with enhanced catalytic efficiency, and controllable synthesis for regulating the performances. Thus, we highlight recent designs of nanoporous metals, alloys, transition metal compounds and hierarchical structures mainly employed in catalysis process. We discuss applied strategies to utilize characteristics of nanoporous metals in the energetic field of catalytic reactions. Moreover, development and evolution of novel controllable synthesis methods are applied in preparation of nanoporous non-noble metals and transition metal compounds. Finally, we present some outlooks and perspectives on the nanoporous metal catalyst and suggest ways for achieving alternative materials in catalysis applications.

关键词： Nanoporous metal Electrochemical catalyst Hierarchical structure Metal-based compound Structure-activity correlation

A SUPERONVERGENCE ANALYISIS FOR FINITE ELEMENT SOLUTION BY THE INTERPOLANT POSTPROCESSING ON IRREGULAR MESHES FOR SMOOTH PROBLEM

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Journal of Computational Mathematics 2001年第3期19卷 323-326页

作者： qi-ding zhu Qun Lin Institute of Science Hunan Normal UniversityChangsha 410081China Institute of System Academy of Mathematics and Systems SciencesChinese Academy of SciencesBeijing 100080China

The post-processing procedure is given by a interpolant postprocessing of the finit element solution by appropriately-define finite dimensional subspaces, The corresponding superconvergence are established on general ... 详细信息

关键词： finite element superconvergence interpolant postprocessing

The relaxation of galaxy clusters at redshift z=0 in IllustrisTNG simulation

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Research in Astronomy and Astrophysics 2020年第12期20卷 261-269页

作者： Chao Li Ling zhu rui Guo National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China

We study the dynamical states of the 30 most massive galaxy clusters in the TNG100 simulation at redshift z = 0 using three types of tracers: stars, dark matter particles and satellite galaxies. If the massive galaxy cluster is spherically symmetric and relaxed, we can obtain the underlying total mass distribution accurately from its dynamical tracers using the spherical Jeans equations. Although the three tracers of clusters have very different number densities, velocity dispersions and anisotropies, they still trace the same total mass profile. We obtain the total mass profiles of clusters using these tracers separately and compare them with the true mass distributions. We find that:(1) the kinematics of dark matter trace the total mass of all clusters well and the mass inferred from dark matter are generally consistent with the true mass profiles with relative deviations smaller than ~ 25% at all radii;(2) stars in ~ 60% massive clusters are approaching equilibrium and the total mass of these clusters inferred from stars have relative deviations smaller than ~50% at all radii. Stellar substructures are rich and the mass inferred from stars tend to be over-estimated in the inner region;and(3) satellite galaxies are unrelaxed in the inner region and become more relaxed as the radius increases. The total mass inferred from satellites are under-estimated in all regions.

关键词： galaxies:clusters:general galaxies:clusters:dynamical tracers methods:numerical

Experimental study of settling and drag on cuboids with square base

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Particuology 2011年第3期9卷 298-305页

作者： Jinsheng Wang Haiying qi Junzong zhu Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Tsinghua University Beijing 100084 China

The drag on non-spherical particles is an important basic parameter for multi-phase flows such as in biomass combustion, chemical blending, and mineral processing. Though there is much experimental research on such particles, there are few results for cuboids. This paper presents data for cuboids with a square base in static glycerin-water solutions of various volume concentrations. Complex motions were observed and characterized. A dimensionless expression is given for terminal velocity ut as a function of Archimedes number Ar which is used to develop an accurate correlation for friction factor CD. The accuracy of the correlation is 7.9% compared to experimental data in the literature. For both square plates and square rods, the terminal velocity per unit mass, ut/mp, was used to characterize the influence of narticle geometry on velocity, which was shown to be linear.

关键词： Cuboid particles Unsteady settling behavior Archimedes number Terminal velocity Drag coefficient

PN code acquisition algorithm in DS-UWB system based on threshold comparison criterion

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Journal of Systems Engineering and Electronics 2009年第1期20卷 216-222页

作者： qi Lina Gan Zongliang zhu Hongbo Coll. of Telecommunications & Information Engineering Nanjing Univ. of Posts and Telecommunication Nanjing 210003 P.R. China

The direct sequence ultra-wideband （DS-UWB） is a promising technology for short-range wireless communications. The UWB signal is a stream of very low power density and ultra-short pulses, and the great potential of DS-UWB depends critically on the success of timing acquisition. A rapid acquisition algorithm for reducing the acquisition time of the coarse pseudo-noise （PN） sequences is proposed. The algorithm utilizes the auxiliary sequence and bisearch strategy based on the threshold comparison criterion. Both theoretical analysis and simulation tests show that with the proposed search strategy and simple operations over the symbol duration at the receiver, the proposed algorithm can considerably reduce the acquisition time even as it maintains the PN sequence acquisition probability in the DS-UWB system over the dense multipath environment.

关键词： direct sequence ultra-wideband pseudo-noise code auxiliary sequence synchronization.

Anti-sintering behavior and combustion process of aluminum nano particles coated with PTFE:A molecular dynamics study

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Defence Technology（防务技术） 2023年第6期24卷 46-57页

作者： Jun-peng Liu Hao-rui Zhang qi-Long Yan Science and Technology on Combustion Internal Flow and Thermostructure LaboratoryNorthwestern Polytechnical UniversityXi'an 710071China

The characteristic of easy sintering of aluminum nanoparticle(ANP)limits its application in solid *** ANP with fluoropolymer could effectively improve its combustion *** find out how the coating layer inhibits sintering and promotes complete combustion of particles from an atomic view,a comparative study has been done for bare ANP and PTFE coated ANP by using reactive molecular dynamics *** sintering process is quantified by shrinkage ratio and gyration *** results show that,at the same heating rate and combustion temperatures,bare ANPs are sintered together after the temperature exceeds the melting point of aluminum but the decomposition of PTFE coating layer pushes particles away and increases reaction surface area by producing small Al-F *** sintering of ANPs which are heated in PTFE is alleviated compared with particles heated in oxygen,but particles still sinter together due to the lack of intimate contact between PTFE and alumina *** effect of temperature on the combustion of PTFE coated ANPs is also studied from 1000 to3500 *** number density analysis shows the particles will not be sintered at any *** fluoride prefers diffusing to the external space and the remained particles are mainly composed of Al,C and *** ignition simulations are performed by adopting micro canonical *** the expansion of aluminum core and the melting of alumina shell,bare ANPs are sintered into a liquid particle *** PTFE coated ANPs,the volatilization of gaseous aluminum fluoride products continually endows particles opposite momentum.

关键词： Aluminum nanoparticle Sintering Combustion Molecular dynamics simulation