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Sintering technology for micro heat pipe with sintered wick

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Journal of Central South university 2010年第1期17卷 102-109页

作者：李西兵汤勇李勇周述璋曾志新 Department of Mechanical and Power Engineering Harbin University of Science and Technology School of Mechanical Engineering Qiqihar University School of Mechanical and Automotive Engineering South China University of Technology

In order to study reasonable sintering technological parameters and appropriate copper powder size range of micro heat pipe (MHP) with the sintered wick, the forming principle of copper powders in wicks and MHP's heat transfer capabilities were first analyzed, then copper powders with different cell sizes and dispersions were sintered in RXL-12-11 resistance furnace under the protection of the hydrogen at different sintering temperatures for different durations of sintering time, and finally the sintered wicks' scanning electron microscope (SEM) images and their heat transfer capabilities were analyzed. The results indicate that the wick sintered with copper powders of larger cell size or smaller size range has better sintering properties and larger heat transfer capabilities; and that the increase of either sintering temperatures or sintering time also helps to improve the wick's sintering properties and heat transfer capabilities, and the former affects more obviously than the latter. Considering both its manufacturing cost and performance requirements, it is recommended that copper powders with the size range of 14.-170 μm are sintered at 900-950℃ for 3.-60 min in practical manufacturing. In addition, two approaches to improve wick's porosity are also proposed through theoretical analysis, which suggests that the larger the wick's porosity, the better the heat transfer capabilities of the MHP.

关键词： micro heat pipe copper powders wick forming principle

Key technology of mine underground mobile positioning based on LiDAR and coded sequence pattern

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中国有色金属学会会刊：英文版 2011年第S3期21卷 570-576页

作者： WANG Zhi1, 2, WU Li-xin1, 2, LI Hui-ying3.1. College of Resources and Civil Engineering, Northeastern university, Shenyang 110004. china 2. Academy of Disaster Reduction and Emergency Management, Ministry of Civil Affairs and Ministry of Education, Beijing Normal university, Beijing 100875, china 3. College of Computer Science and {4., Jilin university, Changchun 13.012, china [a] College of Resources and Civil Engineering Northeastern University Shenyang 110004 China [b] Academy of Disaster Reduction and Emergency Management Ministry of Civil Affairs and Ministry of Education Beijing Normal University Beijing 100875 China [c] College of Computer Science and technology Jilin University Changchun 130012 China

Technologies of underground mobile positioning were proposed based on LiDAR data and coded sequence pattern landmarks for mine shafts and tunnels environment to meet the needs of fast and accurate positioning and navigation of equipments in the mine underground without satellite navigation signals. A coded sequence pattern was employed for automatic matching of 3. scans. The methods of SIFT feature, Otsu segmentation and fast hough transformation were described for the identification, positioning and interpretation of the coded sequence patterns, respectively. The POSIT model was presented for speeding up computation of the translation and rotation parameters of LiDAR point data, so as to achieve automatic 3. mapping of mine shafts and tunnels. The moving positioning experiment was applied to evaluating the accuracy of proposed pose estimation method from LiDAR scans and coded sequence pattern landmarks acquired in an indoor environment. The performance was evaluated using ground truth data of the indoor setting so as to measure derivations with six degrees of freedom.

关键词： LiDAR coded sequence pattern mobile positioning SLAM algorithm POSIT algorithm

Statistical theory for hydrogen bonding fluid system of A_aD_d type (I): The geometrical phase transition

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Science china Chemistry 2006年第6期49卷 499-506页

作者： WANG Haijun1,2, HONG Xiaozhong3. GU Fang1 & BA Xinwu1 1. College of Chemistry and Environment Science, Hebei university, Baoding 071002, china 2. International Center for Materials Physics, Chinese Academy of Sciences, Shenyang 110016, china 3. College of Physics Science and {3., Hebei university, Baoding 071002, china 1. College of Chemistry and Environment Science Hebei University Baoding 071002 China 2. International Center for Materials Physics Chinese Academy of Sciences Shenyang 110016 China 3. College of Physics Science and technology Hebei University Baoding 071002 China

The influence of hydrogen bonds on the physical and chemical properties of hydrogen bonding fluid system of AaDd type is investigated from two viewpoints by the principle of statistical mechanics. In detail, we proposed two new ways that can be used to obtain the equilibrium size distribution of the hydrogen bonding clusters, and derived the analytical expression of a relationship between the hydrogen bonding free energy and hydrogen bonding degree. For the nonlinear hydrogen bonding systems, it is shown that the sol-gel phase transition can take place under proper conditions, which is further proven to be a kind of geometrical phase transition rather than a thermodynamic one. Moreover, several problems associated with the geometrical phase transition and liquid-solid phase transition in nonlinear hydrogen bonding systems are discussed.

关键词： hydrogen bonding fluid, equilibrium free energy, geometrical phase transition.

Electrical property of 8-mol% yttria-stabilized zirconia electrolyte by spark-plasma sintering

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Science china(Technological Sciences) 2004年第5期47卷 569-576页

作者： JIAN Jiawen1,2, CHANG Aimin3. YANG Bangchao2 & ZHANG Yikang4.1. The School of Information Science Engineering, Ningbo university, Ningbo 3.5211, china 2. The School of Microelectronics and Solid-state Electronics, university of Electronic Science and Tech-nology of china, Chengdu 610054. china 3. The Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Urumqi 83.022, china 4. Hongtak (Chengdu) Electronic Co., Ltd, Chengdu 61004., china Correspondence should be addressed to Jian Jiawen 1. The School of Information Science Engineering Ningbo University 315211 Ningbo China 2. The School of Microelectronics and Solid-state Electronics University of Electronic Science and Technology of China 610054 Chengdu China 3. The Xinjiang Technical Institute of Physics and Chemistry Chinese Academy of Sciences 830022 Urumqi China 4. Hongtak (Chengdu) Electronic Co. Ltd 610041 Chengdu China

Spark-plasma sintering (SPS) process was used to sinter ZrO2 (8Y) powders, and a relative density of 99% has been reached at a low temperature (13.0°C) and short dwelling time (10 min) compared to the conventional sintered identical samples (14.0°C 4.h)(CS). By the X-ray diffraction (XRD) patterns, the microstructure of the SPS pellet and CS pellet are both indexed by the cubic unit cell (Fm3.). The finer crystallite size (D111) of the SPS pellet is 154.nm and D111 of the CS pellet is more than 1 μm. The AC impedance spectroscopy shows that the ionic conductivity of SPS pellet is different from that of CS pellet. The activation energy for the SPS ceramics, estimated from the slope in the range of 4.0–800°C, was 91 kJ mol?1, which is in good agreement with CS pellet (96 kJ mol?1), indicating that the conduction mechanism in SPS ceramics is similar to that in CS ceramics.

关键词： yttria-stabilized zirconia electrolyte, spark-plasma sintering, AC impedance.

Paleotemperature changes over the past 3.00 years in eastern Beijing, china: A reconstraction based on Mg/Sr records in a stalagmite

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Chinese Science Bulletin 2003年第4期48卷 395-400页

作者： MA Zhibang1, LI Hongchun2, XIA Ming1, KU Tehlung2, PENG Zicheng3. CHEN Yushu4.& ZHANG Zhaofeng3.1. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, china 2. Department of Earth Sciences, university of Southern California, Los Angeles, CA90089-074., USA 3. Department of Earth and Space Science, university of Science and technology of china, Hefei 23.026, china 4. Beijing Foshan Tourist Service Centre, Beijing 101201, china Institute of Geology and Geophysics. Chinese Academy of Sciences Beijing 100029 China

The Mg/Sr ratio in a stalagmite, which is di-rectly proportional to DMg/Ca, the solid-liquid distribution coefficient of Mg, is proposed as a geochemical thermometer to estimate paleotemperature changes. The paleotempera-ture change in eastern Beijing over the past 3.00 years has been reconstructed by using this thermometer in the stalag-mite ZFFS-1 from Jingdong Cave. The records can be di-vided into two periods: 3.00—2000 aBP, cool and wet, the air temperature averaging 9.8℃; and 2000 aBP—present, hot and dry, the air temperature being 1℃ higher than the mean value (11.7℃) of the past 3.00 years. During 500—200 aBP, the air temperature was about 1.2℃ lower than that of the present, corresponding to the Little Ice Age in Europe. Like d 18O and d 13., Mg/Sr (or DMg/Ca) reflects an obviously warming trend of the past 200 years. These results are sup-ported by historic records.

关键词：北京京东溶洞石笋 Mg/Sr记录古气温测年 3.00年

Threshold quantum secure direct communication without entanglement

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Science china(Physics,Mechanics & Astronomy) 2008年第2期51卷 176-183页

作者： YANG YuGuang1,3.& WEN QiaoYan2 1 College of Computer Science and technology, Beijing university of technology, Beijing {3.,{4. 2 School of Science, Beijing university of Posts and Telecommunications, Beijing 100876,{4. 3.State Key Laboratory of Information Security (Graduate School of Chinese Academy of Sciences), Beijing 10004.,{4. 1. College of Computer Science and technology Beijing University of Technology Beijing 100022 China 3. State Key Laboratory of Information Security (Graduate School of Chinese Academy of Sciences) Beijing 100049 China 2. School of Science Beijing University of Posts and Telecommunications Beijing 100876 China

For the first time, a threshold quantum secure direct communication (TQSDC) scheme is presented. Similar to the classical Shamir's secret sharing scheme, the sender makes n shares, S1, …, Sn of secret key K and each receiver keeps a share secretly. If the sender wants to send a secret message M to the receivers, he en-codes the information of K and M on a single photon sequence and sends it to one of the receivers. According to the secret shares, the t receivers sequentially per-form the corresponding unitary operations on the single photon sequence and ob-tain the secret message M. The shared shares may be reusable if it can be judged that there is no eavesdropper in line. We discuss that our protocol is feasible with current technology.

关键词： quantum secure direct communication threshold secure direct communication quantum secret sharing

Experimental remolding on the caprock's 3. strain field of the Indosinian-Yanshanian epoch in Tongling deposit concentrating area

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Science china Earth Sciences 2005年第7期48卷 863-874页

作者： DENG Jun1,HUANG Dinghua2,WANG Qingfei1,WAN Li1,SUN Zhongshi3.YANG Liqiang1 & GAO Bangfei1 1. State Key Laboratory of Geological Processes and Mineral Resources,china university of Geosciences,Beijing 100083.china 2. Faculty of Earth Sciences,china university of Geosciences,Wuhan 4.0074.china 3. Department of Earth Sciences,Jilin university,Changchun 13.061,china State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Beijing 100083 China Faculty of Earth Sciences China University of Geosciences Wuhan 430074 China Department of Earth Sciences Jilin University Changchun 130061 China

Based on field observations and rheology analysis, we perform one analogue experiment and remold the 3. structural frame of Tongling deposit concentrating area firstly. Then we disassemble and dialyze the 3. structures of the model using the methods of "slicing" and "stripping". A series of sliced planes vertical to the fold hinges show similar landscapes of that in the drill hole profiles. Meanwhile, layer stripping analysis indicates that the deformation features of each layer in the model are qualitatively analogical to those obtained from field observations. Through contrasting the 3. structure between the experimental model and the field phenomena, we verify the following 3. deformation features of the caprock in this area: (1) the Tongling area mainly consists of three series of NE S-typed fold groups; (2) in the uniform stress field, the incoherent folds universally develop in different positions, along different axes as well as in different strata; (3. the faults propagate upward which are mostly inter-bedded detachment faults, while the fold amplitudes decrease while going deeper; and (4. the folds and cleavages are highly developed in the Silurian System indicating that the deformation effect of the Indosin-ian-Yanshanian structural layer terminates at this layer, which suggests that the Silurian System is the crucial layer for the inversion between brittle and plastic deformation domains and the underlying strata are subject to the control of another deformation system with distinct properties.

关键词： Tongling deposit concentrating area Indosinian-Yanshanian epoch 3. structural frame of the caprock analogue experiment slicing and stripping analysis structural model.

Friction Properties of OTS SAMs and Silicon Surface under Water Lubrication

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Journal of Wuhan university of technology(Materials Science) 2009年第2期24卷 273-277页

作者：王馨 State Key Laboratory of Tribology Tsinghua University Institute of Nuclear and New Energy technology Tsinghua University

The friction and wear properties of silicon surface covered with octadecyltrichlorosilane （OTS） self-assembled monolayers （SAMs） were investigated by a UMT-2 microtribometer with and without water as lubricant, and then compared with that of bare silicon surface. Dry friction measurement results show that OTS SAMs have a very low friction coefficient compared to bare silicon surface under lower sliding velocity and normal contact load. However, heavy wear occurs on OTS SAMs under higher contact stress and sliding velocity. Under water lubrication, OTS SAMs can prevent wear obviously and meanwhile present low coefficient of friction even under high velocities, The improved frictional and anti-wear property on OTS SAMs surface is attributed to the hydrophobic property of OTS and hydrodynamic effect of water. Furthermore, a wear critical phase diagram for OTS SAMs with and without water was proposed, which indicates that OTS SAMs working under water lubrication owns a wider range of available load and velocity to reduce friction and prevent wear.

关键词： silicon surface OTS SAMs water lubrication friction wear

Electronic structure and magnetism of R(Fe,Si)_(12) (R=Y,Nd)

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Science china(Physics,Mechanics & Astronomy) 2006年第2期49卷 195-202页

作者： SUN Guang’ai1, CHEN Bo1, DU Honglin2, FAN Zhijian1, GAO Tao3.& QI Xinhua3.. Institute of Nuclear Physics and Chemistry, china Academy of Engineering Physics, Mianyang 621900, china 2. Department of physics, Peking university, Beijing 100871, china 3. Institute of Atomic and Molecular Physics, Sichuan university, Chengdu 610065, china 1. Institute of Nuclear Physics and Chemistry China Academy of Engineering Physics Mianyang 621900 China 2. Department of physics Peking university Beijing 100871 China 3. Institute of Atomic and Molecular Physics Sichuan University Chengdu 610065 China

The newly developed full-potential linearized augmented plane wave (LAPW) and local orbitals (lo) based on standard APW methods are briefly introduced, and the structure and magnetic properties of R(Fe, Si)12 compounds (R = Y, Nd) are calculated using the method. The distribution of Si at different sites is analyzed based on total energy of one crystal unit with structure having been optimized. The characters of magnetic mo-ments, total density of states (TDOS) and partial density of states (PDOS) for different crystal sites Si occupies are obtained and analyzed. The results show that the total mag-netic moments of RFe10Si2 (R = Y, Nd) are larger than those of RFe10M2 (M = Ti, V, Cr, Mn, Mo and W) and the hybridization mechanism is seen as follows. Si(8j) reduce the mag-netic moments of Fe at three sites, however, Si(8f) mainly reduce the magnetic moments of Fe(8i) and Fe(8j) atoms. The Curie temperature is markedly enhanced by the introduc-tion of Si atoms according to spin fluctuation of DOS at Fermi level.

关键词： (L)APW+lo method R(Fe Si)12(R = Y Nd) magnetic moment Density of state.