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Delay-Based User Association in Heterogeneous Networks with Backhaul

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China Communications 2017年第10期14卷 130-141页

作者： Wenchao xia Jun Zhang Shi jin Hongbo Zhu Jiangsu Key Laboratory of Wireless Communications Nanjing University of Posts and Telecommunications National Mobile Communications Research Laboratory Southeast University

The Internet of things(IoT) as an important application of future communication networks puts a high premium on delay issues. Thus when Io T applications meet heterogeneous networks(HetNets) where macro cells are overlaid with small cells, some traditional problems need rethinking. In this paper, we investigate the delay-addressed association problem in two-tier Het Nets considering different backhaul technologies. Specifically, millimeter wave and fiber links are used to provide high-capacity backhaul for small cells. We first formulate the user association problem to minimize the total delay which depends on the probability of successful transmission, the number of user terminals(UTs), and the number of base stations(BSs). And then two algorithms for active mode and mixed mode are proposed to minimize the network delay. Simulation results show that algorithms based on mutual selection between UTs and BSs have better performance than those based on distance. And algorithms for mixed modes have less delay than those for active mode when the number of BSs is large enough, compared to the number of UTs.

关键词： user association backhaul delay small cell HetNet heterogeneous networks IoT

Precision forging technology for aluminum alloy

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Frontiers of Mechanical Engineering 2018年第1期13卷 25-36页

作者： Lei DENG Xinyun WANG Junsong jin Juchen xia State Key Laboratory of Materials Processing and Die & MouldTechnology Huazhong University of Science and Technology Wuhan430074 China Research Institute of Huazhong University of Science and Technology inShenzhen Shenzhen 518057 China

Aluminum alloy is a preferred metal material for lightweight part manufacturing in aerospace, auto- mobile, and weapon industries due to its good physical properties, such as low density, high specific strength, and good corrosion resistance. However, during forging processes, underfilling, folding, broken streamline, crack, coarse grain, and other macro- or microdefects are easily generated because of the deformation characteristics of aluminum alloys, including narrow forgeable temperature region, fast heat dissipation to dies, strong adhesion, high strain rate sensitivity, and large flow resistance. Thus, it is seriously restricted for the forged part to obtain precision shape and enhanced property. In this paper, progresses in precision forging technologies of aluminum alloy parts were reviewed. Several advanced precision forging technologies have been developed, including closed die forging, isothermal die forging, local loading forging, metal flow forging with relief cavity, auxiliary force or vibration loading, casting-forging hybrid forming, and stamping-forging hybrid forming. High-precision alumi- num alloy parts can be realized by controlling the forging processes and parameters or combining precision forging technologies with other forming technologies. The development of these technologies is beneficial to promote the application of aluminum alloys in manufacturing of lightweight parts.

关键词： precision forging aluminum alloy closed dieforging flow control forging hybrid-forming technology

Overview of Impacts of Climate Change and Adaptation in China's Agriculture

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Journal of Integrative Agriculture 2014年第1期13卷 1-17页

作者： WANG jin-xia HUANG Ji-kun YANG Jun Center for Chinese Agricultural Policy Institute of Geographical Sciences and Natural Resources ResearchChinese Academy of Sciences

The purpose of this paper is to document the likely impacts of climate change on China＇s agriculture and the current adaptation efforts made by government and farmers. The review of literature shows that climate change will have a significant impact on agriculture, primarily through its effect on crop yields. The extent of predicted impacts highly depends on the crop, the CO2 fertilization effect assumption and adaptation abilities. Market response to the production shocks resulting from climate change will lessen the impacts on agricultural production predicted by natural scientists. On adaptation, the government＇s major efforts have been in the developing new technologies, reforming extension system and enhancing institutional capacity. Farmers do adapt to climate change, but their adaptation measures cannot fully offset the negative impacts of climate change. The paper concludes and makes implications for future studies.

关键词： climate change agriculture adaptation China

Low-Lying Pentaquark Baryons in Pseudoscalar-Vector SU（3） Skyrme Model

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Communications in Theoretical Physics 2007年第2X期48卷 319-325页

作者： xia Zheng-Tong WANG Shun-jin ZHANG Hua Department of Physics Sichuan University Chengdu 610064 China

For the first time the low-lying J = 1/2 pentaquark states are investigated in the pseudoscalar-vector Skyrme model. Once the conventional baryon properties are fit, other states are predicted without any more adjustable parameters. Furthermore, both symmetry-breaking and decay operators are treated in full. In particular, we focus on the calculations of mass and decay width, and compare them with the experimental data available and relevant theoretical results obtained in other pictures. We recognize that the higher-order contributions, such as the 35 and/or 35 representation admixtures, are not negligible. Our analysis provides some valuable clues to the physical mechanisms, and the oncoming experimental search and/or confirmation could provide a sharp test of our proposal

关键词： nonstandard multiquark Skyrmions hadron mass calculations hadronic decays

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Schatten-p Class(0

Acta Mathematica Sinica,English Series 2015年第4期31卷 703-714页

作者： Lian Hua xiaO xiao Feng WANG jin xia School of Mathematics and Information Science and Key Laboratory of Mathematics and Interdisciplinary Sciences of the Guangdong Higher Education Institute Guangzhou University

In this paper, we discuss the Schatten-p class （0 〈 p≤∞ ） of Toeplitz operators on generalized Foek space with the symbol in positive Borel measure. It makes a great difference from other papers by using the estimates of the kernel and the weight together instead of separately estimating each other. We also get the equivalent conditions when a Toeplitz operator is in the Schatten-p class.

关键词： Schatten class generalized Fock space compact operator

Concurrent Two-Scale Topology Optimization of Thermoelastic Structures Using a M-VCUT Level Set Based Model of Microstructures

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Computer Modeling in Engineering & Sciences 2024年第11期141卷 1327-1345页

作者： jin Zhou Minjie Shao Ye Tian Qi xia State Key Laboratory of Intelligent Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan430074China

By analyzing the results of compliance minimization of thermoelastic structures,we observed that microstructures play an important role in this optimization ***,we propose to use a multiple variable cutting(M-VCUT)level set-based model of microstructures to solve the concurrent two-scale topology optimization of thermoelastic structures.A microstructure is obtained by combining multiple virtual microstructures that are derived respectively from multiple microstructure prototypes,thus giving more diversity of microstructure and more flexibility in design *** effective mechanical properties of microstructures are computed in an off-line phase by using the homogenization method,and then a mapping relationship between the design variables and the effective properties is established,which gives a data-driven model of *** the online phase,the data-driven model is used in the finite element analysis to improve the computational *** compliance minimization problem is considered,and the results of numerical examples prove that the proposed method is effective.

关键词： Two-scale structure topology optimization multiple variable cutting level set data-driven radial basis function thermoelastic structure

Broadband achromatic phase retarder based on metal-multilayer dielectric grating

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Chinese Physics B 2018年第5期27卷 215-219页

作者： Na Li Wei-jin Kong Feng xia Mao-jin Yun College of Physics Qingdao UniversityQingdao 266071China Qingdao Laoshan No.2 Middle School Qingdao 266071China Key Laboratory of Photonics Materials and Technology in Universities of Shandong Qingdao UniversityQingdao 266071China

A new achromatic phase retarder based on a metal-multilayer dielectric grating structure is designed using the rigorous coupled wave analysis method and the genetic *** optimized phase retarder can maintain phase retardation around 90°from 900 nm to 1200 nm,and the maximum deviation is less than 4.5%while the diffraction efficiencies of TE and TM waves are both higher than 95%.Numerical analysis shows the designed phase retarder has a high fabrication tolerance of groove depth,duty cycle and incident *** achromatic phase retarder is simple in design and stable in performance,and can be widely used in optical systems.

关键词： achromatic phase retarder metal-multilayer dielectric grating rigorous coupled wave analysis(RCWA) genetic algorithm(GA)

TiB2 coating formed on nickel substrates by electroplating in molten salt of fluoride

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中国有色金属学会会刊：英文版 2004年第z1期14卷 132-135页

作者： LONG jin-ming GUO Zhong-cheng HAN xia-yun Faculty of Materials and Metallurgical Engineering Kunrning University of Science and Technology Kunming 650093 China Faculty of Materials and Metallurgical Engineering Kunrning University of Science and Technology Kunming 650093 China Faculty of Materials and Metallurgical Engineering Kunrning University of Science and Technology Kunming 650093 China

The TiB2 coatings deposited over nickel substrate by electroplating was investigated, which is in molten salt of a fluoride mixture involving KF, NaF, K2 TiF6 and KBF4. Effects of temperature, cathodic current density (Jc) and duration on the coating's formation were examined. The composition, morphology and structure of the coatings were characterized by scanning electron microscopy (SEM), energy dispersive X-ray detector (EDS) and X-ray diffraction (XRD). The results show that the coatings, with black, smooth and uniform appearance, are composed of predominating TiB2 and small amounts of nickel titanium oxide (Ni0.75 Ti0.125 O). The coatings show a nodular morphology and the grain size is dependent on the Jc and ranges about 1 - 10 μm. There is a linear relationship between the coating's thickness and the time of electrolysis within certain duration range. The reduction of the potassium can take place simultaneously with the electrochemical synthesis of TiB2 as the Jc is in excess of certain level. The hardness of the TiB2 coatings is likely to be deteriorated due to the presence of potassium and Ni0.75Ti0.125 O in the coatings.

关键词： TiB2 coating electroplating molten salt nickel microstructure

Hierarchically spacing DNA probes on bio-based nanocrystal for spatial detection requirements

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Science Bulletin 2019年第13期64卷 934-940页

作者： Lin Gan Ya Wang Meng Zhang Xuehuan xia jin Huang Key Laboratory of Luminescence and Real-Time Analytical Chemistry Ministry of EducationSchool of Chemistry and Chemical EngineeringSouthwest UniversityChongqing 400715China Chongqing Key Laboratory of Soft-Matter Material Chemistry and Function Manufacturing Southwest UniversityChongqing 400715China

Sterically spacing and locating functional matters at the nanoscale exert critical effects on their application,especially for the fluorescence probes whose aggregation causes emission *** we achieved a hierarchical spacing strategy of DNA fluorescence probes for ion detection via locating them separately on rod-like cellulose nanocrystals(CNCs)and further isolating CNCs by pre-grafting long molecular *** chemical structure of CNC and location degree could adjust the interspace of DNA probes(with a molecular length of ca.3.6 nm)in a range of 3.5-6.5 nm with a gradient about 0.2 nm.A length up to micrometer scale of the CNC nanorods was necessary to provide DNA probes with well-separated grafting locations and enough freedom,which brought a vast linear detection range from 10 nmol/L to 5 μmol/L of Hg^2+ *** abundant reactive sites on CNC allowed a grafting pre-location of poly(tert-butyl acrylate)(PtBA)to promote the isolation of DNA *** radical polymerization was employed to adj ust the length of PtBA molecular chains,which increased the linear sensitivity coefficient of Hg^2+ detection by ca.2.5 *** hierarchical nanoscale spacing concept based on chemical design can hopefully cond uce to the development of biosensor and medical diagnosis.A hierarchical spacing strategy was applied to separate DNA fluorescent probes on CNCs and detect ion concentration *** first-level spacing was to locate probes uniformly on CNCs,obtaining a wide linear range;and the second-level spacing was to isolate CNCs with polymer,obtaining an increased linear coefficient.

关键词： Cellulose nanocrystal DNA fluorescence probe Steric spacing Surface modification Mercury ion detection