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Application Prospect of Fission-Powered Spacecraft in Solar System Exploration Missions

Space(Science & Technology) 2021年第1期2021卷 309-323页

作者： Y.Xia j.li R.Zhai j.Wang B.lin Q.Zhou Beijing Institute of Spacecraft Environment Engineering BeijingChina Science and Technology on Reliability and Environmental Engineering Laboratory BeijingChina Institute of Nuclear and New Energy Technology of Tsinghua University The Key Laboratory of Advanced Reactor Engineering and SafetyMinistry of EducationBeijingChina

Fission power is a promising technology,and it has been proposed for several future space *** is being considered for highpower missions whose goal is to explore the solar system and even *** fission power has made great progress when NASA’s 1 kWe Kilowatt Reactor Using Stirling TechnologY(KRUSTY)prototype completed a full power scale nuclear test in *** success stimulated a new round of research competition among the major space *** article reviews the development of the Kilopower reactor and the KRUSTY system *** summarizes the current missions that fission reactors are being considered as a power and/or propulsion *** projects include visiting jupiter and Saturn systems,Chiron,and Kuiper belt object;Neptune exploration missions;and lunar and Mars surface base *** studies suggest that the Fission Electric Propulsion(FEP)/Fission Power System(FPS)is better than the Radioisotope Electric Propulsion(REP)/Radioisotope Power System(RPS)in the aspect of cost for missions with a power level that reaches~1 kWe,and when the power levels reaches~8 kWe,it has the advantage of lower *** a mission that travels further than~Saturn,REP with plutonium may not be cost acceptable,leaving FEP the only *** missions prefer the use of FPS because it satisfies the power level of 10’s kWe,and FPS vastly widens the choice of possible landing *** to the current situation,we are expecting a flagship-level fission-powered space exploration mission in the next 1-2 decades.

关键词： satis Saturn isotope

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Statistical downscaling model for late-winter rainfall over Southwest China

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Science China Earth Sciences 2015年第7期58卷 1827-1839页

作者： RUAN ChengQing li jianPing FENG juan State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of Sciences College of Earth Sciences University of Chinese Academy of Sciences College of Global Change and Earth System Science Beijing Normal University joint Center for Global Change Studies

A statistical downscaling model is built for the late-winter rainfall over Southwest China(SWC).A partial-correlation method is used for selecting *** results show that the selected factors for late-winter rainfall in SWC are sea level pressure in Western Europe(SNAO)and sea surface temperature in Western Pacific(WPT).SNAO is related to the southern pole of North Atlantic Oscillation(NAO)and excites Southern Eurasian teleconnection,which influences the development of the southern branch trough and the water vapor transport to *** indicates the variability of ENSO in the tropical Western *** excites Pacific-East Asia teleconnection and an anticyclone(cyclone)is formed in the southern part of China and suppresses(enhances)rainfall over SWC.A regression statistical downscaling model using SNAO and WPT shows good performance in fitting the variability of late-winter rainfall in the whole SWC region and every observation station,and the model also shows strong robustness in the independent *** statistical model can be used for downscaling output from seasonal forecast numerical models and improve the SWC late winter rainfall prediction in the future.

关键词： statistical downscaling Southwest China late-winter rainfall partial correlation

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Atomistic Investigation of Shock-Induced Amorphization within Micro-shear Bands in Hexagonal Close-Packed Titanium

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Acta Metallurgica Sinica(English Letters) 2024年第9期37卷 1590-1600页

作者： Z.C.Meng K.G.Wang T.Ali D.li C.G.Bai D.S.Xu S.j.li A.H.Feng G.j.Cao j.H.Yao Q.B.Fan H.Wang R.Yang Institute of Metal Research Chinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Interdisciplinary Centre for Additive Manufacturing(ICAM) School of Materials and ChemistryUniversity of Shanghai for Science and TechnologyShanghai 200093China School of Materials Science and Engineering Tongji UniversityShanghai 201804China Key Laboratory for light-Weight Materials Nanjing Tech UniversityNanjing 210009China National Key Laboratory of Science and Technology on Materials Under Shock and Impact School of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China Beijing Institute of Technology Chongqing Innovation Center Chongqing 401135China

The mechanical response of a single crystal titanium sample against(0001)α surface impact was investigated using molecular dynamics ***,non-uniform plastic deformation was observed in the *** high strain rates,amorphization occurred near the edge of the contact region where severe shear strain induced a large number of stacking faults(SFs)and *** contrast,the central part of the contact region underwent less deformation with significantly fewer ***,instead of amorphization by consuming SFs and dislocations,there was a gradual increase in the density of dislocations and SFs during the process of *** local amorphous regions eventually grew into shear bands.

关键词： Shock compression Amorphization Shear band Titanium Molecular dynamics

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Strengthening and deformation mechanism of high-strength CrMnFeCoNi high entropy alloy prepared by powder metallurgy

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journal of Materials Science & Technology 2023年第1期132卷 119-131页

作者： Y.Xing C.j.li Y.K.Mu Y.D.jia K.K.Song j.Tan G.Wang Z.Q.Zhang j.H.Yi j.Eckert Faculty of Materials Science and Engineering Kunming University of Science and TechnologyKunming 650093China Laboratory for Microstructures Institute of MaterialsShanghai UniversityShanghai 200444China School of Mechanical Electrical&Information EngineeringShandong UniversityWeihai 264209China College of Materials Science and Engineering Chongqing UniversityChongqing 400044China Erich Schmid Institute of Materials Science Austrian Academy of SciencesJahnstraße 12Leoben A-8700Austria Department of Materials Science Chair of Materials PhysicsMontanuniversität LeobenJahnstraße 12Leoben A-8700Austria Adjunct with National University of Science and Technology«MISiS» Leninsky Prosp.4Moscow 119049Russia

Multiphase CrMnFeCoNi high-entropy alloys(HEAs)were prepared by a powder metallurgy process com-bining mechanical alloying(MA)and vacuum hot-pressing sintering(HPS).The single-phase face-centered cubic(FCC)HEA powder prepared by MA was sintered into a bulk HEA specimen containing FCC phase matrix along with precipitated M 23 C 6 phase and nanoscaleσphase *** the sintering temper-ature was 1223 K,the ultimate strength reaches 1300±11.6 MPa,and the elongation exceeds 4%±0.6%.Microstructural characterization reveals that the formation of nanoscale particles and deformation twins play critical roles in improving the strain hardening(SH)*** the MA time promoted the formation of the precipitated phase and enhanced the SH ability by increasing the number of precip-itated *** SH capacity increases significantly with increasing sintering temperature,which is attributed to a significant enhancement in the twinning capacity due to grain growth and the reduced number ofσphase *** systematic studies,the planar glide of dislocations was found to be the main mode of deformation,while deformation twinning appeared as an auxiliary deformation mode when the twinning stress was *** the formation of precipitates leads to grain bound-ary and precipitation strengthening effects,crack initiation is more prominent owing to increased grain boundary brittleness around the precipitated M 23 C 6 *** prominence of crack initiation is a contra-diction that must be reconciled with regard to precipitation *** work serves as a useful reference for the preparation of high-strength HEA parts by powder metallurgy.

关键词： High entropy alloy Powder processing Grain reﬁnement Precipitation strengthening Deformation twinning

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Parallel algorithm for generalized matrix eigen-problem and its application in calculation of crystal electronic structure

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Chinese Science Bulletin 1997年第13期42卷 1086-1089页

作者： Sun, jC Deng, jX Cao, jW Wang, DS Zhang, WQ li, j R and D Center for Parallel Software Institute of Software Chinese Academy of Sciences Beijing 100080 China Insntute of Physics Chinese Academy of Sciences Beijing 100080 China Institute of Applied Physics Beijing Univ. of Sci. and Technology Beijing 100083 China

1 Problem and algorithmMANY computing tasks arising from computational physics, chemistry and biology are relatedto solving so-called generalized eigen-decomposition problems. Consider the following general-ized eigen... 详细信息

关键词： parallel computation eigen-problem crystal electronic structure.

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Implementation of a Prototype VoIP System

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journal of Computer Science & Technology 2000年第5期15卷 480-484页

作者：刘喜成李仲同 CentreforCommunicationsSystemsResearch UniversityofCambridgeUK NetworkingandComputingSystemsGroup MotorlaSemiconductorProductsSector

VoIP (Voice over IP) is a rapidly growing area with great market potential. To promote it for both commercial and research purposes, a prototype VoIP system based on state-of-the-art Motorola communication techniques has been developed. It is a gateway system integrating a PBX and a VoIP module. All components that H.323 defines to support VoIP are implemented in the VoIP module, though in a simplified manner. As an embedded system, the system features real timeness and task distributiveness. A number of additional techniques are used to improve the performance, including noise suppression, zero copy, and buffer structure optimization. When refined in interoperability, the system will also readily serve as a product.

关键词： VoIP gateway gatekeeper communication common platform embedded system voice processing H.323

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STEADY-STATE CREEP OF UNIDIRECTIONAL C/C COMPOSITE WITH PYROLYTIC CARBON MATRIX

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Acta Metallurgica Sinica(English Letters) 1998年第6期11卷 412-416页

作者： R.Shi G.X.Hu H.j.li M.K.Kang Shanghai jiaotong Univ Shanghai China

The steady-state creep behavior of unidirectional C/C(1-D-C/C) composite with pyrolytic carbon matrix was investigated at high temperatures up to 2160℃ and under tensile stress from 133.83 to 213.46MPa. Based on the creep experiment of single specimen method, the apparent activation energy and the stress exponent for steadystate creep were determined by the use of a self-made apparatus and an auto-testing system. Value of apparent activation volume is provided and the creep mechanism has also been discussed.

关键词： 1-D-C/C steady-state creep thermal activation

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GO/MgO/Mg interface mediated strengthening and electromagnetic interference shielding in AZ31 composite

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journal of Magnesium and Alloys 2023年第10期11卷 3800-3814页

作者： Z.Y.Xu C.F.Fang C.j.li R.Wang X.P.Zhang j.Tan Y.M.Wang Key Laboratory of Solidification Control and Digital Preparation Technology(liaoning Province) School of Materials Science and EngineeringDalian University of TechnologyDalian 116024China Faculty of Materials Science and Engineering Kunming University of Science and TechnologyKunming 650093China College of Materials Science and Engineering Chongqing UniversityChongqing 400045China Key Laboratory of Materials Modification by Laser Ion and Electron Beams(Ministry of Education)School of Materials Science and EngineeringDalian University of TechnologyDalian 116023China

More requirements of electromagnetic interference(EMI) shielding performance are put forward for lightweight structural materials due to the development of aerospace and 5G communications. Herein, graphene oxide(GO) decorated with SnO_(2) coating is introduced as reinforcement into AZ31 Mg alloy. During the smelting process, the MgO layer is in situ gernerated at interface between GO and the molten Mg alloy matrix by consuming SnO_(2). In the solid state, such kind of interface structure can improve the GO-Mg interface bonding intensity,also significantly generate stacking faults. The AZ31 composite reinfoced by trace modified GO(0.1 wt%) exhibits high ultimate strength and almost the same elongation with AZ31 alloy. Compared with AZ31 alloy, the yield strength and ultimate tensile strength of composite are increased by 33.5% and 23.7%, respectively. Meanwhile, the multi-level electromagnetic reflection from the multi-layer structure of GO and the interface polarization caused by the MgO mid-layer can significantly improve EMI shielding performance. The appropriate interface design strategy achieves the effect of “two birds with one stone”.

关键词： Metal-matrix composites Mechanical properties EMI shielding Microstructures

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EFFECT OF COLD WORKING ON THE AGING PROPERTIES OF Cu-Cr-Zr-Mg ALLOY BY ARTIFICIAL NEURAL NETWORK

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Acta Metallurgica Sinica(English Letters) 2004年第5期17卷 741-746页

作者： j.H.Su H.j.li Q.M.Dong P.liu B.X.Kang B.H.Tian CollegeofMaterialsScienceandEngineering NorthwesternPolytechnicalUniversityXi＇an710072China GollegeofMaterialsScienceandEngineering HenanUniversityofScienceandTechnologyLuoyang471003China

A developmental research has been carried out to deal with the high performance of Cu-Cr-Zr-Mg lead frame alloy by artificial neural network (ANN). Using the cold working to assist in the aging hardening can improve the the hardness and electrical conductivity properties of Cu-Cr-Zr-Mg lead frame alloy. This paper studies the effect of different extent of cold working on the aging properties by a supervised ANN to model the non-linear relationship between processing parameters and the properties. The back-propagation (BP) training algorithm is improved by Levenberg-Marquardt algorithm. A basic repository on the domain knowledge of cold worked aging processes is established via sufficient data mining by the network. The predicted values of the ANN coincide well with the tested data. So an important foundation has been laid for prediction and optimum controlling the rolling and aging properties of Cu-Cr-Zr-Mg alloy.

关键词： Cu-Cr-Zr-Mg alloy cold working aging artificial neural network (ANN)

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THE EFFECT OF POWERFUL OXYGEN EVOLUTION METAL-OXIDE ON THE ELECTROOXIDATION OF METHANOL

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Acta Metallurgica Sinica(English Letters) 2001年第2期14卷 103-108页

作者： X.C. Chen, Y.X. liu, j. li, j.j. Chen and H.Z. liu (Department of Metallurgy Science and Engineering, Central South University, Changsha 410083, China) Department of Metallurgy Science and Engineering Central South University

An improved thermal decomposition method is used to prepare modified titanium base anodes. Some researches have been carried out to learn about the oxygen evolution properties of RuMn, RuCo and RuEu etc. in H2SO4 solution and their effect on the electrooxidation of methanol if they are added into the catalytic layers of Pt/Ti electrodes. The result indicates that the Pt/Ti electrodes containing RuMn, RuCo, RuCe and RuEu, etc. metal oxide catalysts with the powerful evolution property exhibit a higher electro-catalytic activity towards methanol electrooxidation than Pt/Ti electrodes without composite metal oxide catalysts.

关键词： Anodes Decomposition Methanol Oxidation Titanium

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