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Tribological Performance of TiB_2-Ni Composite Coating Deposited by APS

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稀有金属材料与工程 2012年第S1期41卷 481-486页

作者： Zhu Hongbin,Li Hui,Li Zhuoxin beijing University of Technology,beijing 100124,china beijing Univ Technol Beijing 100124 Peoples R China

TiB2-Ni composite powders were prepared by pressurized hydrogen reduction cladding with different proportion of *** coatings were then prepared by *** microstructures and the phase composition of the powders as well as the deposited coatings were analyzed by scanning electron microscopy(SEM)and X-ray diffraction(XRD).The coatings were tested using a ring-on-disc tribometer from ambient temperature to 300°C.A sprayed Cr3C2-NiCr coating was tested as a *** morphologies of the worn surface of the coatings were observed and *** is found that the TiB2-Ni composite coatings present higher friction coefficient than that of the Cr3C2-NiCr coating at room temperature due to the adhesive wear mechanism,whereas the main wear mechanism of Cr3C2-NiCr coating is rupture and ***,at high temperature,the friction coefficient of the TiB2-Ni composite coating decreases as a result of B2O3 solid lubricant,which alleviates the adhesive wear on ***,the TiB2-Ni composite coating greatly reduces the mass loss of the boron cast iron.

关键词： TiB2-Ni composite coating APS wear behavior

Microstructure and Mechanical Properties of Magnesium Alloy AZ31B Brazed Joint Using a Zn-Mg-Al Filler Metal

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Journal of Materials Science & Technology 2010年第8期26卷 743-746页

作者： Li Ma, Dingyong He, Xiaoyan Li and Jianmin Jiang College of Materials Science and Engineering, beijing University of Technology, beijing 100124, china College of Materials Science and Engineering Beijing University of Technology

In order to join the similar magnesium alloy, a novel Zn-Mg-Al filler metal was designed and applied to braze AZ31B plates by using high-frequency induction brazing technique. The microstructure, phase constitution and fracture morphology of the brazed joint were investigated. The experimental results show that MgZn2 phase in the original filler metal is completely consumed in the brazing process. Moreover, α-Mg solid solution and α-Mg＋MgZn eutectoid structure formed in the brazing region due to the intensive alloying between the molten filler metal and the base metal in the brazing process. Test results indicate that the shear strength of the brazed joint is 56 MPa. The fracture morphology of the brazed joint shows intergranular fracture mode, where crack originates from the hard α-Mg＋MgZn eutectoid structure.

关键词： Filler metal Brazing Microstructure Mechanical properties

Design,fabrication and experimental research for an electrohydrodynamic micropump

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Science china(Technological Sciences) 2010年第10期53卷 2839-2845页

作者： YU He, YU Jian & MA ChongFang Key lab of Enhanced Heat Transfer & Energy Conservation, Ministry of Education and Key lab of Heat Transfer & Energy Conversion, beijing municipality, College of Enviromental and Energy Engineering, beijing University of Technology, beijing 100124, china Key lab of Enhanced Heat Transfer & Energy Conservation Ministry of Education and Key Lab of Heat Transfer & Energy Conversion Beijing Municipality College of Enviromental and Energy Engineering Beijing University of Technology

This paper presented a novel electrohydrodynamic (EHD) micropump based on MEMS technology. The working mechanisms and classification of EHD micropump were introduced. The fabrication process of EHD micropump was presented with the material selection,optimal design of microelectrode and assembly process. Static pressure experiments and flow experiments were carried out using different fluid and the channel depth. The results indicated that the micropump could achieve a maximum static pressure head of 268 Pa at an applied voltage of 90 V. The maximum flow rate of the micropump-driven fluid could reach 106 μL/min. This paper analyzed the future of combining micropump with heat pipe to deal with heat dissipation of high power electronic chips. The maximum heat dissipation capacity of 87 W/cm2 can be realized by vaporizing the micropump-driven liquid on vaporizing section of the heat pipe.

关键词： electrohydrodynamic (EHD) MEMS micropump electronic cooling

Nitrogen removal via nitrite from municipal landfill leachate

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Journal of Environmental Sciences 2009年第11期21卷 1480-1485页

作者： WU Lina, PENG Chengyao, ZHANG Shujun, PENG Yongzhen Key laboratory of beijing for Water Quality Science and Water Environment Recovery Engineering, beijing University of Technology, beijing 100124, china. Key laboratory of beijing for Water Quality Science and Water Environment Recovery Engineering Beijing University of Technology Beijing 100124 China

A system consisting of a two-stage up-flow anaerobic sludge blanket （UASB）, an anoxic/aerobic （A/O） reactor and a sequencing batch reactor （SBR）, was used to treat landfill leachate. During operation, denitrification and methanogenesis took place simultaneously in the first stage UASB, and the effluent chemical oxygen demand （COD） was further removed in the second stage UASB. Then the denitrification of nitrite and nitrate in the returned sludge by using the residual COD was accomplished in the A/O reactor, and ammonia was removed via nitrite in it. Last but not least, the residual ammonia was removed in SBR as well as nitrite and nitrate which were produced by nitrification. The results over 120 d （60 d for phase I and 60 d for phase II） were as follows： when the total nitrogen （TN） concentration of influent leachate was about 2500 mg/L and the ammonia nitrogen concentration was about 2000 mg/L, the shortcut nitrification with 85%-90% nitrite accumulation was achieved stably in the A/O reactor. The TN and ammonia nitrogen removal efficiencies of the system were 98% and 97%, respectively. The residual ammonia, nitrite and nitrate produced during nitrification in the A/O reactor could be washed out almost completely in SBR. The TN and ammonia nitrogen concentrations of final effluent were about 39 mg/L and 12 mg/L, respectively.

关键词： short-cut nitrification up-flow anaerobic sludge blanket anoxic/aerobic reactor sequencing batch reactor landfill leachate

Progress of Solid Electrolytes and the Electrochemical Sensors

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Journal of Materials Science & Technology 1997年第3期13卷 173-178页

作者： Yanruo HONG(National lab. on Solid Electrolytes and Metallurgical Testing Techniques, University of Science and Technology beijing,beijing 100083, china) National lab. on Solid Electrolytes and Metallurgical Testing Techniques University of Science and Technology Beijing Beijing 100083 China

Four types of solid state electrochemical sensors and their general principles are introduced in the paper. The novel type-IV sensors developed in the last few years are emphasized to study hereafter. The ways to design new electrochemical sensors and the directions to develop new solid electrolytes for new electrochemical sensors are also discussed.

关键词： Li Ba Progress of Solid Electrolytes and the Electrochemical Sensors Wang

A disjoint algorithm for seismic reliability analysis of lifeline networks

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Earthquake Engineering and Engineering Vibration 2002年第2期1卷 207-212页

作者： Han Yang Dalian University of Technology,Dalian 116023,china SUN Shaoping beijing municipal Engineering Research Institute,beijing 100037,china Senior Engineer Dalian University of Technology Dalian China beijing municipal Engineering Research Institute Beijing China

The algorithm is based on constructing a disjoin kg t set of the minimal paths in a network *** this paper, cubic notation was used to describe the logic function of a network in a well-balanced state,and then the sharp-product operation was used to construct the disjoint minimal path set of the network.A computer program has been developed,and when combined with decomposition technology,the reliability of a general lifeline network can be effectively and automatically calculated.

关键词： lifeline network reliability disjoint product DFS algorithms logic function sharp-product

Study on attribute characterization for reservoir dynamic monitoring by seismic

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Science china Earth Sciences 2008年第S2期51卷 218-225页

作者： CHEN XiaoHong1,3,LI JingYe2,3 & ZHAO Wei4 1 Key lab of Geophysical Exploration of CNPC,china Petroleum University,beijing 102249,china 2 Basin & Reservoir Research Center,china Petroleum University,beijing 102249,china 3 State Key laboratory of Petroleum Resource and Prospecting,china University of Petroleum,beijing 102249,china 4 Research Center of CNOOC,beijing 100027,china Key lab of Geophysical Exploration of CNPC China Petroleum University Beijing China State Key laboratory of Petroleum Resource and Prospecting China University of Petroleum Beijing China Basin & Reservoir Research Center China Petroleum University Beijing China Research Center of CNOOC Beijing China

Study on characterizing reservoir parameters dynamic variations by time-lapse seismic attributes is the theoretical basis for effectively distinguishing reservoir parameters variations and conducting time-lapse seismic interpretation,and it is also a key step for time-lapse seismic application in real oil fields. Based on the rock physical model of unconsolidated sandstone,the different effects of oil saturation and effective pressure variations on seismic P-wave and S-wave velocities are calculated and analyzed. Using numerical simulation on decoupled wave equations,the responses of seismic amplitude with different offsets to reservoir oil saturation variations are analyzed,pre-stack time-lapse seismic attributes differences for oil saturation and effective pressure variations of P-P wave and P-S converted wave are calculated,and time-lapse seismic AVO (Amplitude Versus Offset) response rules of P-P wave and P-S converted wave to effective pressure and oil saturation variations are compared. The theoretical modeling study shows that it is feasible to distinguish different reservoir parameters dynamic variations by pre-stack time-lapse seismic information,including pre-stack time-lapse seismic attributes and AVO information,which has great potential in improving time-lapse seismic interpreta-tion precision. It also shows that the time-lapse seismic response mechanism study on objective oil fields is especially important in establishing effective time-lapse seismic data process and interpreta-tion scheme.

关键词： time-lapse seismic dynamic monitoring rock physical model pre-stack attribute Amplitude Versus Offset (AVO)

北京2022年冬奥会与冬残奥会延庆赛区,北京,中国

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世界建筑 2024年第4期 42-45页

作者： china Architecture Design&Research Group beijing General municipal Engineering Design&Research Institude Co.Ltd Ecosign Moutain Resort Planners Ltd Planungsbüro Deyle GmbH 中国建筑设计研究院有限公司北京市市政工程设计研究总院有限公司加拿大伊克森山地景区规划有限公司德国戴勒有限公司

北京2022年冬奥会与冬残奥会延庆赛区核心区规划和场馆及配套设施设计始于2017年1月,于2021年竣工投入使用。项目位于燕山山脉军都山以南的小海坨南麓,风景秀丽、山高林密、地形复杂、用地狭促,是最具挑战性的北京冬奥赛区。延庆赛区的... 详细信息

北京2022年冬奥会与冬残奥会延庆赛区核心区规划和场馆及配套设施设计始于2017年1月,于2021年竣工投入使用。项目位于燕山山脉军都山以南的小海坨南麓,风景秀丽、山高林密、地形复杂、用地狭促,是最具挑战性的北京冬奥赛区。延庆赛区的设计理念是“山林场馆,生态冬奥”,通过建筑、景观和赛道设计的联合创新,打造冬奥场馆历史上新的里程碑,同时最大限度减少对环境的扰动,使建筑与自然景观有机结合,在满足精彩赛事要求的基础上,建设一个融于自然山林中的冬奥赛区。

关键词：军都山残奥会联合创新延庆融于自然冬奥场馆最大限度

Quantum threshold group signature

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Science china(Physics,Mechanics & Astronomy) 2008年第10期51卷 1505-1514页

作者： YANG YuGuang1,2,3 & WEN QiaoYan4 1 College of Computer Science and Technology, beijing University of Technology, beijing 100124, china 2 State Key laboratory of Integrated Services Network, Xidian University, Xi’an 710071, china 3 State Key laboratory of Information Security (Graduate University of Chinese Academy of Sciences), beijing 100049, china 4 State Key laboratory of Networking and Switching Technology, beijing University of Posts and Tele-communications, beijing 100876, china College of Computer Science and Technology Beijing University of Technology Beijing China State Key laboratory of Integrated Services Network Xidian University Xi’an China State Key laboratory of Information Security Graduate University of Chinese Academy of Sciences Beijing China State Key laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing China

In most situations, the signer is generally a single person. However, when the message is written on behalf of an organization, a valid message may require the approval or consent of several persons. Threshold signature is a solution to this problem. Generally speaking, as an authority which can be trusted by all members does not exist, a threshold signature scheme without a trusted party appears more attractive. Following some ideas of the classical Shamir’s threshold signature scheme, a quantum threshold group signature one is proposed. In the proposed scheme, only t or more of n persons in the group can generate the group signature and any t-1 or fewer ones cannot do that. In the verification phase, any t or more of n signature receivers can verify the message and any t-1 or fewer receivers cannot verify the validity of the signature.

关键词： threshold quantum signature trusted party quantum cryptography