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Asynchronous cooperative communication systems:A survey on signal designs

science china(Information sciences) 2011年第8期54卷 1547-1561页

作者： WANG HuiMing 1,2.& xiA xiangGen 3 1 school of Electronic and Information engineering,{2., xi’an 710049,china 2.State Key Laboratory of Integrated Services Networks, xidian university,xi’an 710049, china 3 Department of Electrical and Computer engineering,university of Delaware,Newark,DE 19716,USA 1. school of Electronic and Information engineering Xi’an Jiaotong University Xi’an 710049 China2. State Key Laboratory of Integrated Services Networks Xidian University Xi’an 710049 China3. Department of Electrical and Computer Engineering University of Delaware Newark DE 19716 USA

Cooperative communications is a promising technique for future high speed wireless *** systems may be formulated as virtual multi-input multi-output (MIMO) systems where spatial/cooperetive diversity is a key advantage. However,different from MIMO systems,one of the major chal- lenges for cooperative communications systems is that the cooperative transmissions in cooperative systems may be neither time nor frequency synchronized,since the transmissions are from multiple cooperative nodes at different *** existing signal designs for co-located MIMO systems may not be able to collect the cooperative diversity in cooperative communications *** paper gives an overview of recent research efforts on combating the time and frequency asynchronism of the cooperative communication *** focus on the signal designs (or space-time codings/modulations) to achieve full cooperative diversity,and summarize some of the resent distributed space-timing coding and space-frequency coding techniques to combat timing errors and frequency offsets,and in the meantime to achieve full cooperative diversity,in both one-way and two-way cooperative networks.

关键词： cooperative communications time and frequency offsets space-time coding space-frequency codes full cooperative diversity linear receiver

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Study of Multistage Project Risk Identification-Assessment Process Based on Objective Orientation

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厦门大学学报（自然科学版） 2002年第S1期41卷 242-243页

作者： YANG Cai-xia, XU Yu (school of Management, xi’an jiaotong university,{2., china)

Risk management of projects is about the real time ev aluation and making of decisions proactively in order to maximize the probabilit y of achieving or surpassing the targets set for project objectives. Project objective generally includes three elements: time, cost, quality. Risk occurrin g in the projects will affect these three factors to some various degrees in the end. There are different emphases in each stage and integrated balanced goals b etween the three factors. A large complex engineering project generally consists of several stages each of which has variable objective combinations leading to variable important risks. In order to achieve strategic goals on the schedule under the restriction of lim ited resources, the paper gives the analysis of the so-called risk identificati on-assessment process on the basis of objective orientation. In this paper the set of involved mostly hazards is presented in terms of given objective weight v ector, and so is the model of risk ranking .By reducing the range of risk factor s step by step, risk manager could pay more attention to important ventures and effectively control of them. According to different objective combination at different stages, primary risk f actor sets at different stages are given. With the probability and their various effects to project objectives, evaluation of these sets is made aiming to r educing of the scope of risks and providing decision maker with a better decisio ns support. Successful projects are those, which focus on the relevant business objectives t hroughout the whole process and seek to information integration across project l ife cycle. This paper also introduces the idea of real time process of risk iden tification-assessment and presents a flow chart as a demonstration.

关键词： risk identification-assessment project objectiv e objective weight vector risk ranking

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Electrical breakdown characteristic of a Ce-doped W-Cu contact material

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Rare Metals 2010年第3期29卷 261-264页

作者： HU Kewen,CHEN Mianzhi,and YE Heng school of materials {2. and engineering,xi’an university of Technology,xi’an 710048,china school of materials {2. and engineering Xi’an University of Technology Xi’an China

W-Cu composite powder doped with Ce （1.5 wt.%） was prepared by mechanical alloying （MA）,and the W-Cu contact material was fabricated by hot pressing sintering in an electrical vacuum *** microstructure,electric conductivity,hardness,and breakdown voltage of the Ce-doped W-Cu alloy were measured and compared with a conventional W-Cu alloy prepared by powder *** results show that microstructural refinement and uniformity can improve the breakdown behavior and the electric arc stability of the Ce-doped W-Cu contact ***,the Ce-doped W-Cu contact material shows the characteristic of spreading electric arc,which is beneficial to electric arc erosion.

关键词： doping rare earth W-Cu alloy electrical breakdown

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Interface Stability of the SiC Particles/Fe Matrix Composite System

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Journal of Wuhan university of Technology(materials {2.) 2006年第3期21卷 49-53页

作者：汤文明 school of materials {2. and engineering Hefei University of TechnologyHefei 230009China

The interface reaction between the SiC particles （ SiCp ） and Fe was stndicd during sintering the SiCp reinforced Fe matrix composites at 142. K for 1 h. In the composite having 3wt% （weight ratio） SiCp （the 3SiCp/ Fe composite）, the interface reaction products of Fe3 Si, the carbon precipitates, and Fe3 C or pearlite were generated. Fe3 Si coustructs the bright matrix of the reaction zone in the original situation of the SiCp. The carbon precipitates are randondy embedded in the reaction zone. Fe3 C or pearlite exists at the grain boundaries of the Fe matrix. As increasing the SiCp concentration in the SiCp/ Fe composite, the inteusity of the interface reaction between SiCp and Fe iacreases. After the 10SiCp/ Fe composite （ having 10wt .% SiCp ） sintered at 142. K for 1 h, all of SiCp are decomposed, and replaced by the reaction zone composed of Fe3 Si and the carbon precipitates. No Fe3 C or pearlite was genertaed during the reaction. The effects of the techniques of oxidizing of SiCp , coating SiCp by interaction with the Cr powder, and alloying the Fe matrix by adding the Cr element on the interface stability of the SiCp/ Fe composite system were also investigated, respectitely. The oxide membrane and the coating layer on SiCp can inhibit the interface reaction between SiCp and Fe by isolating SiCp from the Fe matrix during sintering. The interface reaction does not occur in the 3 SiCp/ Fe- 10 Cr composite but in the 3 SiCp/ Fe-5 Cr composite. In the SiCp/ Fe-Cr alloy composites, the interface reaction between SiCp and the Fe- Cr alloys is weaker than that between SiCp and Fe . The Cr element behaves as a diluent, it causes a redaction in the interface reaction, which is proportional to the amount of the element added.

关键词： interface reaction interface stability oxidation of SiC coating alloying

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High temperature polyimide nanocomposites containing twodimensional nanofillers for improved thermal stability and capacitive energy storage performance

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Nano Research 2024年第8期17卷 7746-7755页

作者： Ding Ai Yuting Han Zongliang xie xi Pang Yuan Chang He Li Chenglong Wu Yonghong Cheng Guanglei Wu State Key Laboratory of Electrical Insulation and Power Equipment School of Electrical EngineeringXi’an Jiaotong UniversityXi’an 710049China Institute of materials for Energy and Environment State Key Laboratory of Bio-Fibers and Eco-TextilesCollege of Materials Science and EngineeringQingdao UniversityQingdao 266071China

Future electronic devices toward high integration and miniaturization demand reliable operation of dielectric materials at high electric fields and elevated ***,the electrical deterioration caused by Joule heat generation remains a persistent challenge to ***,the solution-processed polyimide(PI)nanocomposites with unique two-dimensional(2.)alumina nanoplates are *** improvements in the breakdown strength,charge–discharge efficiency and discharged energy density at elevated temperatures have been demonstrated in the composites,owing to simultaneously suppressed conduction loss and increased thermal conductivity upon the incorporation of 2. Al_(2.O_(3) nanofillers possessing excellent dielectric insulation and thermophysical *** predominance of Al_(2.O_(3) nanoplates in enhancing thermal stability and high-temperature capacitive performance over nanoparticles and nanowires is validated experimentally and is further rationalized via finite element ***,the Al_(2.O_(3) nanoplates filled PI nanocomposite exhibits a hightemperature capability up to 2.0℃ and remarkable efficiency(e.g.≥95% at 2.0 MV/m)over a wide temperature range,which outperforms commercial dielectric polymers and rivals the state-of-the-art polyimide nanocomposites.

关键词： capacitors polymer nanocomposites high temperature energy storage thermal stability

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Clathrate structure of YB_(3)C_(3) for high-performance thermoelectrics with superior mechanical properties

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Journal of Materiomics 2024年第4期10卷 783-791页

作者： Yangfan Cui Shuai Duan xiaojun Wang Qinghang Tang Jinyang xi xiaobing Liu Yongsheng Zhang xin Chen Laboratory of High Pressure Physics and material science(HPPMS) School of Physics and Physical EngineeringQufu Normal UniversityQufuShandong273165China materials Genome Institute Shanghai UniversityShanghai200444China Advanced Research Institute of Multidisciplinary science Qufu Normal UniversityQufuShandong273165China

Exploring high-performance thermoelectric materials with improved mechanical properties is important for broadening the application scope and the assembly requirement of stable *** work presents an effective strategy to discover hard thermoelectric material by inserting foreign atoms in the rigid covalent *** demonstrate this in boron-carbon clathrate VII structure,showing a promising candidate for highly efficient thermoelectric energy conversion,especially with Y atom filled in the cage,with a peak zT of 0.73 at 1,000 *** ab initio calculations indicate that YB_(3)C_(3) system has low lattice thermal conductivity of 4.5 W/(m·K)at 1,000 K due to the strong rattling of encaged Y *** strongly covalent framework provides highly degenerate band structures consisting of heavy and light electron pockets,which can maintain high carrier mobility arising from small effective mass and thus large group ***,high power factor can be achieved in YB_(3)C_(3) for both electron and hole *** addition,it exhibits well mechanical properties and a Vickers hardness of 2..7 GPa because of the strong covalent boron-carbon *** work provides a novel avenue for the search of high-performance thermoelectric materials with excellent mechanical properties,based on boron-carbon clathrate structure.

关键词： Clathrate structure Thermoelectric performance First-principles calculations Mechanical properties Thermal conductivity

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Ferroelectric perovskite PbTiO_(3)for advanced photocatalysis

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Rare Metals 2024年第9期43卷 4038-4055页

作者： Shuang Zhao Shi-Shi Shen Lu Han Bo-Chao Tian Na Li Wei Chen xi-Bao Li school of materials and Metallurgy University of Science and Technology LiaoningAnshan 114051China school of materials {2. and engineering Nanchang Hangkong UniversityNanchang 330063China Department of Chemistry National University of SingaporeSingapore 117543Singapore

The ferroelectric semiconductor material PbTiO_(3)exhibits remarkable spontaneous polarization and photoelectric properties,positioning it as a promising polar *** internal electric field of ferroelectrics can separate photocarriers and enhance the catalytic performance of ***,when combined with other semiconductors,PbTiO_(3)contributes to the construction of a depolarization field,extending the catalytic applications of PbTiO_(3)***_(3)exhibits optical absorption,semiconductor,and piezoelectric *** piezoelectric polarization field enhances charge separation,modulates band structure,surface charge conduction,and heterojunction interface charge conduction,thereby amplifying photocatalytic *** paper begins by examining the structure,properties,and preparation methods of PbTiO_(3).Subsequently,it delves into the optimization of PbTiO_(3)'s structure and performance,exploring applications in photocatalysis as a ferroelectric *** is placed on the detailed discussion of surface modification,heterostructure formation,and ferroelectric polarization of PbTiO_(3)*** aspects are thoroughly explored for their role in regulating activity and optimizing the performance of photocatalysis and photopiezoelectric *** conclusion,the paper addresses the current research status of PbTiO_(3)ferroelectric materials and highlights the challenges that lie *** intention is to provide valuable references for the ongoing research in PbTiO_(3)ferroelectric materials.

关键词： PbTiO_(3) Ferroelectric polarization Photocatalysis Piezoelectric catalysis Polarization

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Thermodynamic Analysis of the Formation of In-situ Reinforced Phases In Cast Al-4.5Cu Alloy

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Journal of Wuhan university of Technology(materials {2.) 2008年第3期23卷 342-345页

作者：梁艳峰 State Key Laboratory for Mechanical Behavior of materials School of Materials EngineeringXi’an Jiaotong University school of materials&Chemical {2. Xi’an Technological UniversityXi'an 710032China

The thermodynamic analysis of the formation of in-situ reinforced phases in （TiB2.Al3Ti）/Al-4.5Cu composites prepared by mixed salts reaction was conducted, and heat changes of mixed salts system were analyzed by differential thermal analysis（DTA）.The results show that although TiB2.possesses the strongest formation ability in Al-Ti-B ternary system, [Ti] is relatively excessive in the in-situ reaction and it combines with Al to form AlaTi phase. The reinforced phases are TiB2.and AlaTi in the produced composites due to the reaction taking place to form reinforced phase with the addition of mixed salts into Al-4.5Cu melt between 900 ℃ and 1 032.℃.

关键词： in-situ composites thermodynamic, TiB2 Al3Ti

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The Research on the Decision-making Mechanism of china′s Monetary Policy Regulation

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Systems science and Systems engineering 2002年第4期11卷 431-438页

作者： GUO Ju′eThe school of Management, xi′an jiaotong {2., xi′an 710049, china The school of Management Xit an Jiaotong University Xi'an 710049 China

The article adopts the quarterly data of the monetary and macroeconomics variables from 1978～1999, applies the asymmetrical information game analysis, the regression and cointegration error-correction model, to investigate on the decision-making mechanism of money supply and money regulation project. It suggests the regulation process which central bank controls with instruments of the monetary policy and the mode detail of its operation.

关键词： the cointegration error-correction model the determining mechanism of money supply the determining mechanism of regulation project the mode of regulating operation

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Understanding and unveiling the electro-chemo-mechanical behavior in solid-state batteries

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SusMat 2024年第2期4卷 75-88页

作者： Yunlei Zhong xia Zhang Yong Zhang Peng Jia Yuebin xi Lixing Kang Zhenjiang Yu Key Laboratory of Multifunctional Nanomaterials and Smart Systems Division of Advanced MaterialsSuzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of SciencesSuzhouChina Institute of Applied materials Helmholtz Centre Berlin for Materials and EnergyBerlinGermany school of Electronic and Information engineering Changshu Institute of TechnologyChangshuJiangsuChina State Key Laboratory of Biobased material and Green Papermaking Qilu University of TechnologyJinanShandongChina

Solid-state batteries(SSBs)are attracting growing interest as long-lasting,thermally resilient,and high-safe energy storage *** an emerging area of battery chemistry,there are many issues with SSBs,including strongly reductive lithium anodes,oxidized cathodes(state of charge),the thermodynamic stability limits of solid-state electrolytes(SSEs),and the ubiquitous and critical *** this Review,we provided an overview of the main obstacles in the development of SSBs,such as the lithium anode|SSEs interface,the cathode|SSEs interface,lithium-ion transport in the SSEs,and the root origin of lithium intrusions,as well as the safety issues caused by the *** and overcoming these obstacles are crucial but also extremely challenging as the localized and buried nature of the intimate contact between electrode and SSEs makes direct detection *** reviewed advanced characterization techniques and discussed the complex ion/electron-transport mechanism that have been plaguing ***,we focused on studying and revealing the coupled electro-chemo-mechanical behavior occurring in the lithium anode,cathode,SSEs,and beyond.

关键词： advanced characterization techniques chemo-mechanical effects interface

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