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Influence of Ru addition on microstructure and stress-rupture property of Ni-based single crystal superalloys

2010 Chinese Control and Decision Conference

＜正＞Electric power steering system（EPS） develops with the automobile entering the people’s *** can alleviate people’s burden from operation,make people have more energy to make decision and tackle various operation conditions,and improve reliability and security of the operation *** this paper,based on a type of EPS whose motor axis is same as steering column,the authors proposed a new type EPS with intelligent feedforward（EPS-IFF）. This new system can improve efficiency and intelligence of the system,and make the output of torsion fast,accurate and *** the physical force is alleviated the intelligence expend is alleviated *** can accomplish the power assistant steering fast and accurately,and then the system capability will be improved overall.

关键词： Electric Power Steering System Feedforward Control Expert System

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Progress in Natural science:materials International 2010年第1期20卷 61-69页

作者： Jing-yang CHEN~1,Qiang FENG~(1,2),La-mei CAO~3,Zu-qing SUN~1 1.State Key Laboratory for Advanced Metals and materials,university of science and technology beijing, beijing 100083,China 2.national center for materials service safety,university of science and technology beijing,beijing 100083,China 3.national Key Laboratory of science and technology on Advanced High Temperature Structural materials, beijing Institute of Aeronautical materials,beijing 100095,China State Key Laboratory for Advanced Metals and materials University of Science and Technology Beijing Beijing 100083 China national center for materials service safety University of Science and Technology Beijing Beijing 100083 China national Key Laboratory of science and technology on Advanced High Temperature Structural materials Beijing Institute of Aeronautical Materials Beijing 100095 China

The effects of Ru on the microstructure and stress-rupture property were investigated in two experimental Ni-based single crystal superalloys with and without Ru addition(5.1%,mass fraction).The results indicate that the morphology ofγ' precipitates in the dendrite core and interdendritic region are intermediate and nearly spherical,respectively,in the Ru-free alloy after being aged at 1100℃for 8 *** Re partitioning ratio increases due to Ru addition and Ru partitioned preferentially to theγphase in both dendrite core and interdendritic region of the Ru-containing alloy,which results in more negative lattice misfit and more cuboidalγ' ***,theγ' volume fraction increases while the precipitate size and y channel width decreases due to Ru addition in both dendrite core and interdendritic *** addition improves the stress-rupture life at 1100℃/140 MPa significantly due to higherγ' volume fraction,more negative lattice misfit and a well rafting structure as well as lessγchannel width.

关键词： Ni-based superalloys ruthenium elemental partitioning ratio lattice misfit γ’ morphology stress-rupture property

Effects of complexing agents on acidic electroless nickel deposition

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Rare Metals 2010年第4期29卷 401-406页

作者： JIN Ying YU Hongying YANG Dejun SUN Dongbai national center for materials service safety University of Science and Technology Beijing Beijing 100083 China Corrosion andProteetion center School of Materials Science andEngineering University of Science and Technology Beijing Beij'ing 100083 China

Our previous study reported the influences of different complexing agents on electroless nickel （EN） by examining the properties of the deposits. In the present work, the effects of four common-used complexing agents on EN deposition rate and the stability of solution pH values were examined, either with an acetic pH buffer agent or absent of them. It is indicated that the pH buffeting effect of them is dominative when the EN solution is lack of the pH buffer. Under this situation, the EN deposition rate increases with the concentration of complexing agents increasing. The EN deposition rate decreases with fin＇ther adding the complexing agent when the solution already has enough pH buffer capability. Electrochemical impedance spectroscopy obtained during EN deposition illustrates that, in this case, the enhanced reaction resistance is the main reason for a lower deposition rate. However, the influence of polarization caused by mass transfer is not negligible at high complex ratio for sodium citrate and malic acid EN solutions.

关键词： electroless nickel complexing agents electrochemical impedance spectrum reaction resistance pH value

Experimental study on fire smoke movement in a multi-floor and multi-room building

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science China(Technological sciences) 2005年第3期48卷 292-304页

作者： ZHONG Maohua 1, 2 , LI Peide 2 , LIU Tiemin 1 , WEI Xing 1, 2 & LIAO Guangxuan 2 1. national center of safety science and technology, State Administration of Work safety, beijing 100029, China 2. State Key Laboratory of Fire science, university of science and technology of China, Hefei 230026, China national center of safety science and technology State Administration of Work Safety Beijing China State Key Laboratory of Fire science University of Science and Technology of China Hefei China

Fire smoke movement of multi-floor and multi-room (MFMR) fire was studied at the model test building in State Key Laboratory of Fire science (SKLFS). The ingredient, temperature, air pressure difference and air velocity of smoke were measured and analyzed. Meanwhile, the hazard of smoke ingredient to exposed occupants was analyzed based on the national standard, Occupational Exposure Limit for Hazardous Agents in the Workplace (GBZ2-2002). The experimental results showed that the maximum temperature difference in MFMR fire was located along the vertical height from the fire source. With the spreading and diffusion of smoke, the temperature of smoke layer would tend to be no difference. In the fire of woodpile and kerosene, the main smoke ingredients such as SO 2 , CO and CO 2 would first exceed human’s average physiological limit, while smoke ingredients such as NO and NO 2 would come behind. Because of the higher fluctuation range and frequency of air pressure difference of smoke in multi-layer building fire, the fire smoke would spread around everywhere of the passageway and made the human evacuation more difficult.

关键词： multi-floor and multi-room,fire experiment,smoke spread,smoke toxicity.

Electrochemical impedance characteristics of LC4 aluminum alloy treated with ZH1 technique

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Rare Metals 2002年第1期21卷 48-55页

作者： zhang Wei, LI Jiuqing, WU Yinshun, and HE Jianping Corrosion and Protection center, university of science and technology beijing, beijing 100083, China Corrosion and Protection center University of Science and Technology Beijing 北京 100083

Zhl technique was used to form a corrosion resistant layer on LC4alloy. the composition of the layer was studied by X-rayphotoelectron spectroscopy (XPS). It is found that the layer iscomposed of oxides of metals on the sub- strate, such as Al_2O_3,ZnO, MgO_, CuO, and MnO_2. The elecrochemical impedance spectrums(EIS) of LC4 aluminum alloy specimen were measured in NaCl solutionsto study the mechanism of the corrosion resistance of the alloytreated with Zh1 technique.

关键词： aluminium alloy rare earth metal electrochemical impedance corrosion

Effect of Heating Rate Before Tempering on Reversed Austenite in Fe-9Ni-C Alloy

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Journal of Iron and Steel Research International 2012年第9期19卷 73-78页

作者： zhang Kun , TANG Di , WU Hui-bin ( national Engineering Research center of Advanced Rolling , university of science and technology beijing , beijing 100083 , China ) national Engineering Research center of Advanced Rolling University of Science and Technology Beijing Beijing China

The alloy was reheated to 580℃ for tempering at rates of 2 , 5 , 10 , 20 , and 40℃ / s , respectively , after *** amount , distribution , and stability of reversed austenite were investigated by X-ray diffraction ( XRD ) and electron back scatter diffraction ( EBSD ) .The microstructure and cryogenic impact energy were studied by scanning electron microscope ( SEM ), transmission electron microscope ( TEM ) and Charpy V-notch ( CVN ) *** results showed that when the sample was heated at 10℃ / s , the volume fraction of reversed austenite exhibited maximum of 8% ; the reversed austenite was uniform along all kinds of boundaries ; the reversed austenite contained higher concentration of carbon which enabled it to be more *** cryogenic toughness of the alloy was greatly improved when heated at 10℃ / s , as the fracture surface observation showed that it mainly fractured in ductile rupture mode , which was consistent with the results of cryogenic impact energy.

关键词： 9Ni steel heating rate reversed austenite cryogenic toughness

Mechanical Property and Microstructural Characterization of C-Mn-Al-Si Hot Dip Galvanizing TRIP Steel

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Journal of Iron and Steel Research International 2012年第8期19卷 29-36页

作者： JIANG Hai-tao1, DING Wei1,2, TANG Di1, HUANG Wei1 (1. national Engineering Research center for Advanced Rolling technology, university of science and technology beijing, beijing 100083, China 2. School of Material and Metallurgy, Inner Mongolia university of science and technology, Baotou 014010, Inner Mongolia, China) national Engineering Research center for Advanced Rolling technology University of Science and Technology Beijing Beijing China School of Material and Metallurgy Inner Mongolia University of Science and Technology Baotou Inner Mongolia China

Mechanical properties and microstructure in high strength hot dip galvanizing TRIP steel were investigated by optical microscope (OM), transmission electron microscope (TEM), X-ray diffraction (XRD), dilatometry and mechanical testing. On the heat treatment process of different intercritical annealing (IA) temperatures, isothermal bainitic transformation (IBT) temperatures and IBT time, this steel shows excellent mechanical properties with tensile strength over 780 MPa and elongation more than 22%. IBT time is a crucial factor in determining the mechanical properties as it confirms the bainite transformation process, as well as the microstructure of the steel. The microstructure of the hot dip galvanizing TRIP steel consisted of ferrite, bainite, retained austenite and martensite during the short IBT time. The contents of ferrite, bainite, retained austenite and martensite with different IBT time were calculated. The results showed that when IBT time increased from 20 to 60 s, the volume of bainite increased from 14.31% to 16.95% and the volume of retained austenite increased from 13.64% to 16.28%; meanwhile, the volume of martensite decreased from 7.18% to 1.89%. Both the transformation induced plasticity of retained austenite and the hardening of martensite are effective, especially, the latter plays a dominant role in the steel containing 7.18% martensite which shows similar strength characteristics as dual-phase steel, but a better elongation. When martensite volume decreases to 1.89%, the steel shows typical mechanical properties of TRIP, as so small amount of martensite has no obvious effect on the mechanical properties.

关键词： TRIP steel isothermal bainitic transformation martensite mechanical property

Slurry Preparation and Rolling of Semi-solid 60Si2Mn Spring Steel

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Journal of materials science & technology 2003年第6期19卷 613-616页

作者： Weimin MAO, aimin ZHAO, Dong YUN, Leping zhang and Yonglin KANGSchool of materials science and Engineering, university of science & technology beijing, beijing 100083, China Sch. of Mat. Sci. and Eng. Univ. of Sci. and Technol. Beijing Beijing 100083 China

The nondendritic semi-solid slurry preparation of 60Si2Mn spring steel has been studied in this paper. The experiments have shown that when stirred for 2 min on the test condition, the semi-solid slurry with 50%-60% fraction solid and spherical primary austenitic grains in the size of 100-300 μm can be obtained and is easy to be discharged from the bottom little hole of the stirring chamber. The nondendritic slurry of 60Si2Mn spring steel can be rolled into given plate form successfully, but the solid phase and liquid phase is easy to be separated in rolling process so that the solid primary austenite is concentrated in the center and the liquid is near the edge of the rolled plate. The rupture strength and elongation of the plate rolled only once with semi-solid slurry are lower than that of the traditionally repeated hot-rolled plate of 60Si2Mn spring steel.

关键词： 60Si2Mn Semi-solid Electromagnetic stirring Rolling

A user-space file system for on-demand legacy desktop software

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science China(Information sciences) 2011年第6期54卷 1142-1150页

作者： zhang YouHui 1,2 , SU GeLin 1,2 & ZHENG WeiMin 1,2 1 Department of Computer science and technology, Tsinghua university, beijing 100084, China 2 Tsinghua national Laboratory for Information science and technology, Tsinghua university, beijing 100084, China Department of Computer science and technology Tsinghua University Beijing China Tsinghua national Laboratory for Information science and technology Tsinghua University Beijing China

Some user-level virtualization technologies have been used to convert legacy software (like the existing Windows desktop applications) into the on-demand software without any modification. To give the client a friendly and compatible method to access on-demand legacy software across the Internet, this paper presents a clientend file system for this usage case. It is a Windows user-space file system based on the cloud storage (where the on-demand software is stored), which converts the local file system accesses into remote visits. Quite a few optimizations are adopted and adjusted to suit the file-access-pattern of on-demand software, including the local cache, metadata/data/software prefetch and content-addressable storage (CAS), to decrease the number of remote visits and/or to overlap IO (input/output) operations with software execution. Detailed access-pattern analyses are also presented. This file system has been implemented and tests show that it is practical for much daily-used software-a local cache of limited size can provide up to 80% hit ratio and the corresponding overhead of running-time is about 37%. Owing to this method, on any compatible and networked computer, a user can use his/her personalized software conveniently although it does not exist on the local host.

关键词： on-demand software software as a service user-space file system cloud storage