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CRYOGENIC PROPERTIES OF AI-SiC COMPOSITES AND EFFECT OF MATRIX CHARACTERISTICS AND REINFORCEMENT TYPE

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Acta Metallurgica Sinica(English Letters) 1994年第2期7卷 149-154页

作者： MA Zhongyi, LU Yuxiong, BI JingInstitute of Metal Research, Chinese Academy of Sciences. Shenyang, ChinaZHANG YuzhengNortheastern University, Shenyang. China manuscript received 16 may, 1994

The tensile tests on the silicon carbide whisker and paniculate reinforced 2124A1 and 2024Al alloy composites fabricated by P/ M technique were carried out at the temperatures ranging from room temperature to - 196C . and the fracture surfaces were examined. The cryogenic strength of the composites increases with the decreasing test temperature. Clean interface is beneficial to the improvement in cryogenic strength of the composites. The effect of the interface characteristics on the paniculate composite is less than that on the whisker composite. With the decreasing temperature, the increase in strength of the whisker composite is more than that of the paniculate composite, which could be attributed to different strengthening mechanism.

关键词： composite aluminum silicon carbide properly

Experimental Study on Non-proportional Multiaxial Strain Cyclic Characteristics and Ratcheting of U71Mn Rail Steel

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Journal of Materials Science & Technology 2002年第1期18卷 13-16页

作者： Guozheng KANG, Qing GAO, Lixun CAI, Yafang SUN and Xianjie YANGDepartment of Applied Mechanics and Engineering, Southwest Jiaotong University, Chengdu 610031, China [ manuscript received December 4, 2000, in revised form February 20, 2001] Dept. of Appl. Mech. and Eng. Southwest Jiaotong Univ. Chengdu 610031 China

An experimental study was carried out on the strain cyclic characteristics and ratcheting of U71Mn rail steel subjected to non-proportional multiaxial cyclic loading. The strain cyclic characteristics were researched under the strain-controlled circular load path. The ratcheting was investigated for the stress-controlled multiaxial circular, elliptical and rhombic load paths with different mean stresses, stress amplitudes and their histories. The experiment shows that U71Mn rail steel features the cyclic non-hardening/softening, and its strain cyclic characteristics depend greatly on the strain amplitude but slightly on its history. However, the ratcheting of U71Mn rail steel depends greatly not only on the values of mean stress and stress amplitude, but also on their histories. In the meantime, the shape of load path and its history also apparently influence the ratcheting. The ratcheting changes with the different loading paths.

关键词： U71 Mn steel Ratcheting Cyclic plasticity Non-proportional load

A Biblock Wavelet Zero Tree Coding for Hyperspectral Imagery Data Compression

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Chinese Journal of Lasers 2001年第4期 23-30页

作者： YAN Jingwen SHEN Guiming HU Xiaoyi XU Fang (The Dept. of Electronic Engineering, Xiamen University, Xiamen 361005, China) received Aug. 14, 2000 revised manuscript received Nov. 6, 2000

In this paper, a biblock zero tree compression coding (BBZTC) method, based on wavelet zero tree compression coding (ZTC), is used to exploit redundancy in hyperspectral imagery data. Because of ZTC scanning every wavelet zero tree coefficients with low efficiency, BBZTC method outperforms ZTC in the aspects of high compression ratio, simple real time implementing, and higher coding/decoding speed, and convenient real time transmission. The experimental results show that this method can obtain the compression ratio 17～40 times of 224 spectral bands to remove the spectral correlation without any coding by using KLT, and the total compression performance of KLT+BBZTC method is better than the method of KLT and other one dimensional transformation (such as DCT) to remove the spectral correlation. To compare with the total compression ratio of KLT+JPEG method and SFCVQ method, this method reaches 180 at the PSNR of 33.6 db. This method is superior to the present any other method at compression rate.

关键词： wavelet transformation zero tree coding biblock zero tree coding spectral feature coding vector quantization (SFCVQ)

电光调QCO_2激光器的六温度模型理论与速率方程理论比较分析

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物理学报 2001年第12期50卷 2369-2374页

作者：田兆硕王骐李自勤王雨三哈尔滨工业大学可调谐激光技术国家重点实验室哈尔滨150001

分别利用速率方程理论和六温度模型理论对Q开关CO2 激光器动力学过程进行了理论分析比较 ,实验上测得电光调Q射频波导CO2 激光器脉冲激光建立时间及峰值功率与速率方程理论和六温度模型理论计算结果一致 .但速率方程理论计算的激光脉冲... 详细信息

分别利用速率方程理论和六温度模型理论对Q开关CO2 激光器动力学过程进行了理论分析比较 ,实验上测得电光调Q射频波导CO2 激光器脉冲激光建立时间及峰值功率与速率方程理论和六温度模型理论计算结果一致 .但速率方程理论计算的激光脉冲宽度较“窄” ,并且几乎没有拖尾 ,而六温度模型理论计算的脉冲激光波形有明显的拖尾 ,符合实际测量的波形 .另外 ,六温度模型理论可以全面反映激光器工作气体中不同分子能级的能量转移过程。

关键词：电光调QCO2激光器六温度模型理论速率方程理论比较分析

Synthesis of Diethyl Oxalate by a Coupling-Regeneration Reaction of Carbon Monoxide

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Journal of Energy Chemistry 2002年第Z1期 57-62页

作者： Fandong Meng,Genhui Xu,Baowei Wang,Xinbin Ma1. School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China 2. Luoyang Petrochemical Engineering Corporation, Luoyang 471003, China[manuscript received March 13, 2002 revised Apr

This article describes a process for the synthesis of diethyl oxalate by a coupling reaction of carbon monoxide, catalyzed by palladium in the presence of ethyl nitrite. The kinetics and mechanism of the coupling and regeneration reaction are also discussed. This paper presents the results of a scale-up test of the catalyst and the process based on an a priori computer simulation.

关键词： CO coupling diethyl oxalate kinetics and mechanism simulation scale-up test

Ectopic pancreaticobiliary drainage accompanied by proximal jejunal adenoma:A case report

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World Journal of Gastroenterology 2009年第35期15卷 4467-4470页

作者： Dong-Sheng Wu,Wei-Xia Chen,Xiao-Peng Wang, Department of Radiology,West China Hospital of Sichuan University,Chengdu 610041,Sichuan Province,China Author contributions:Wu DS and Wang XP collected data and carried out the research Wu DS wrote the manuscript Chen WX revised the article. Department of Radiology West China Hospital of Sichuan University Chengdu 610041 Sichuan Province China. wxchen25@***

A patient with obstructive jaundice was examined by multidetector row helical computed tomography (MDCT)and magnetic resonance imaging(MRI),and his common bile duct was observed to be leading into the distal portion of the horizontal duodenum with a pancreaticobiliary union outside the duodenal wall. A mass was also found in the proximal *** the above findings were confirmed by subsequent surgery,thus contrast-enhanced MDCT and MRI with appropriate image post-processing could provide non- invasive and accurate information regarding anatomy and lesions of the pancreaticobiliary duct and duodenal union,which may improve the feasibility of surgery and reduce postoperative complications.

关键词： Ectopic drainage Pancreaticobiliary malju-nction Computed tomography Magnetic resonanceimaging

Motional Quantum State Engineering Via a Single Laser-ion Interaction

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Chinese Journal of Lasers 2001年第3期 79-81页

作者： ZHENG Shibiao (Department of Electronic Science and Applied Physics, Fuzhou University, Fuzhou 350002, China) received Sep. 19, 2000 revised manuscript received Nov. 13, 2000

We propose a scheme to prepare superpositions of several Fock states for the one dimensional motion of a trapped ion. In the scheme the ion is simultaneously excited by N+1 laser beams, with the n th  laser tuned to the n th  upper vibrational sideband. After a short interaction time, a measurement of the internal state may project the vibrational motion onto a superposition of the first N+1 Fock states. The scheme can be easily generalized to synthesize entangled states for the two dimensional ion motion. Key words quantum state engineering, laser ion interaction, superpositionatory of Spectroscopy and Materials, Anhui Normal University, Wuhu 241000) Abstract: A+A/E pattern CIDEP of TEMPO was obtained after laser irradiation of fluoranthene/TEMPO/benzene system. Using the interaction model of excited triplet molecule and doublet rdical, considering the equal population of the doublet spin states of the radical triplet pairs as initial condition, employing the second order perturbation theory and the motion equation of density matrix, the radical spin polarization of the system was theoretically calculated.

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Optimizing Film Design and Application forthe Recordable Compact Disk Developedby Two Cyanine Dye Samples

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Chinese Journal of Lasers 1999年第4期 3-5页

作者： LI Jing and GAN Fuxi (Shanghai Institute of Optics and Fine Mechanics, The Chinese Academy of Sciences, Shanghai 201800, China) received March 4, 1999 revised manuscript received Apr. 12, 1999

The optical constants of two cyanine dye films we prepared have been measured by a RAP 1 typed spectroscopic ellipsometer. On the basis of making a simplified model for the wafers of a recordable compact disk (CD R), the optimizing designs for them developed by the cyanine dye films are given. In addition, the dynamic storage performances of two sample disks have been tested by our dynamic storage testing system. Measurement results of the sample disks are obtained to test our film designs.

关键词： cyanine dye ellipsometer CD R film design dynamic storage performance

Crystalline Silicotitanate: a New Type of Ion Exchanger for Cs Removal from Liquid Waste

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Journal of Materials Science & Technology 2002年第3期18卷 206-210页

作者： Bo YU, Jing CHEN and Chongli SONGInstitute of Nuclear Energy Technology, Tsinghua University, Beijing 102201, China [ manuscript received January 18, 2001, in revised form April 13, 2001] Tsing Hua Univ Inst Nucl Energy Technol Beijing 102201 Peoples R China

The research and developments of a new type of inorganic ion exchanger, crystalline silicotitanate (CST) are reviewed. This material is stable against radiation, and the CST has high selectivity for Cs over Na, K and Rb. It performs well in acidic, neutral, and basic solutions. The results of ion exchange tests show that CST is an excellent candidate for Cs removal from high-level liquid waste.

关键词： Crystalline silicotitanate Cesium High-level liquid waste