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改进的Vrentas-Duda扩散模型及其应用(Ⅰ)预测弱极性分子在聚合物膜中的扩散系数

赵欣 , 李继定 , 陈剑 , 陈翠仙

膜科学与技术 doi:10.3969/j.issn.1007-8924.2003.06.003

在膜分离过程中,渗透物分子在聚合物膜内的扩散过程,是影响聚合物膜分离性能的关键因素.详细考察了目前被广泛使用的Vrentas-Duda扩散模型,对其进行改进,提出了新的计算ζ的公式.根据新提出的公式,对聚苯乙烯/甲苯(PS/toluene)、聚苯乙烯/乙苯(PS/ethylbenzene)、聚乙酸乙烯酯/甲苯(PVAc/toluene)3种体系中弱极性渗透物分子的扩散系数进行了预测,其较之原Vrentas-Duda扩散模型、Ju改进的Vrentas-Duda扩散模型有更好的预测结果.

关键词: 自由体积 , 扩散模型 , 聚合物膜 , 扩散系数

掺Mn硅酸锌薄膜中微量氧化锌对发光强度的影响

席俊华 , 季振国 , 刘坤 , 王超 , 杜鹃

无机材料学报 doi:10.3724/SP.J.1077.2006.01506

利用溶胶-凝胶法结合高温热处理在硅衬底上制备了掺Mn硅酸锌薄膜, 用XRD、SEM、UV-Vis吸收谱和PL谱测试了样品的结晶性能与光学性能, 并分析了热处理温度对掺Mn硅酸锌薄膜的结晶性能和光学性能的影响. 实验结果发现, ZnO的适量存在对掺Mn薄膜的发光有增强作用. 进一步的分析认为, 这一现象的机理可由G.G. Qin提出的量子约束-发光中心 (QCLC) 模型进行解释, ZnO中受激发的电子和空穴通过隧穿效应到达硅酸锌基体中复合发光, 从而增强发光强度.

关键词: 硅酸锌 , ZnO , photoluminescence , quantum confinement-luminescence center

Extended quantum confinement luminescence center model for photoluminescence from oxidized porous silicon and nanometer-Si-particle- or nanometer-Ge-particle-embedded silicon oxide films

Materials Research Bulletin

Through analysis of the latest experimental results reported in the literature and obtained in our laboratory, we have extended our previous quantum confinement/luminescence center model for the photoluminescence mechanism of porous Si and of nanometer-silicon-particle-embedded Si oxide films (G.G. Qin and Y.Q. Jia, Solid State Commun. 86, 559 (1993)). We consider that there are three main types of competitive photoexcitation/photoemission processes and that the process in which photoexcitation occurs in the nanometer silicon particles (NSPs) while photoemission occurs in the luminescence centers (LCs) in the SiOx layers very close to the NSPs is usually the major one. We discuss under what conditions the other two types of processes will dominate. We believe that the extended quantum confinement/luminescence center model is a physical model that is suitable for the photoluminescence from silicon oxide films embedded with NSPs or nanometer Ge particles (NGPs), as well as from oxidized porous Si. (C) 1999 Elsevier Science Ltd.

关键词: oxides;luminescence;defects;blue-light emission;visible luminescence;optical-properties;nanocrystals;mechanism;dependence;sio2-films;absorption;spectra;defects

Reply to "Comment on 'Low-temperature lattice excitation of icosahedral Al-Mn-Pd quasicrystals' "

Physical Review B

In response to the comment by Wang and Qin, we have rewritten our equation (22) following the coordinate system of Dina, et al. [J. Wuhan Univ. (Nature Science Edition) 3, 23 (1992)]. According to the thermodynamic stability condition and the experiment of Capitan et al., we have chosen the new parameters of the phason elastic constants. Based on this, we have recalculated the coefficients of the expressions on the vibrational denty of states and the specific heat of the icosahedral Al-Nin-Pd quasicrystal. Our results are still in agreement with the experimental data measured by Walti et al. [Phys. Rev. B 57, 10 504 (1998)]. It demonstrates that our method is useful for dealing with the low-temperature vibrational excitation of icosahedral quasicrystals.

关键词: quasi-crystals;diffuse-scattering

掺Mn硅酸锌薄膜中微量氧化锌对发光强度的影响

席俊华 , 季振国 , 刘坤 , 王超 , 杜鹃

无机材料学报 doi:10.3321/j.issn:1000-324X.2006.06.038

利用溶胶-凝胶法结合高温热处理在硅衬底上制备了掺Mn硅酸锌薄膜,用XRD、SEM、UV-Vis吸收谱和PL谱测试了样品的结晶性能与光学性能,并分析了热处理温度对掺Mn硅酸锌薄膜的结晶性能和光学性能的影响.实验结果发现,ZnO的适量存在对掺Mn薄膜的发光有增强作用.进一步的分析认为,这一现象的机理可由G.G.Qin提出的量子约束-发光中心(QCLC)模型进行解释,ZnO中受激发的电子和空穴通过隧穿效应到达硅酸锌基体中复合发光,从而增强发光强度.

关键词: 硅酸锌 , 氧化锌 , 光致发光 , 量子约束-发光中心

考虑夹杂间相互影响的弱界面颗粒复合材料等效模量预测的一般细观力学方法

陈康 , 许希武 , 马凯

材料科学与工程学报

基于Ju和Chen提出的颗粒增强复合材料的一般细观力学方法,采用Qu给出的一阶近似修正的Eshelby张量,本文建立了考虑夹杂之间相互影响的含任意分布弱界面颗粒增强多相复合材料等效模量预测的一般细观力学方法,通过体积均匀化方法得到了一组细观力学本构方程.分别推导了忽略夹杂之间相互影响的弱界面多相复合材料宏观模量表达式以及考虑夹杂之间相互影响的弱界面两相复合材料的宏观模量表达式.此外,还给出了几种特殊复合材料体系在考虑界面弱化下的宏观等效性能参数的解析表达式,在界面粘结完好的假设下,给出的表达式均可以退化成经典的细观力学预测结果.在考虑夹杂之间相互影响的情况下,本文预测结果与实验数据吻合很好,验证了模型的有效性.

关键词: 夹杂之间相互影响 , 轻微弱化界面 , 细观力学 , 等效性能参数 , 颗粒增强复合材料

天然气井油管悬挂器腐蚀失效分析

刘守平 , 周上祺 , 王佳眉 , 任勤

腐蚀学报(英文)

用金相显微镜、扫描电镜、X射线衍射仪和X射线能谱仪对天然气井油管悬挂器腐蚀失效进行了检测分析,并对天然气井油管悬挂器用35CrMo钢进行了盐雾试验,结果表明,天然气中的水和CO2是引起腐蚀的主要介质,腐蚀产物主要是FeCO3,高速天然气冲刷和钢中的非金属夹杂加剧了腐蚀的速度. CORROSION FAILURE ANALYSIS OF AN OIL TUBE USED IN NATURAL GAS WELL LIU Shou-ping,ZHOU Shang-qi,WANG Jia-mei,REN Qin Chongqing University A failed oil tube used in natural gas well was examined by optical microscope,scanning electron microscope ,X-ray diffractometer and X-ray spectrometer.Corrosion behavior of 35CrMo steel samples of the oil tube were investigated by means of salt spray tests in the laboratory.The results show that CO2 and H2O are primary factors in the corrosion of oil tube.The corrosion product is FeCO3,non-metallic inclusions in the steel and erosion of natural gas fluid played an important role in accelerating the corrosion. oil tube; natural gas well; 35CrMo steel; failure analysis; corrosion

关键词: 悬挂器 , null , null , null

EFFECT OF MAGNETIC FIELD ON CALCITONIN GENE-RELATED PEPTIDE IN PERIODONTAL LIG AMENTS OF RATS

X. Chang , K. Qin and Y.L.Lu Orthodontic Department of Stomatology College , China Medical University , Sheny ang 110001 , China

金属学报(英文版)

proach change of CGRP with time in periodontal ligaments of rats in magnetic field, maxillae of 28 Wistar rats of 6 7 weeks were placed in magnetic fields of permanent magnets Nd 2 Fe 4 B. Changes of CGRP with t ime in maxillary periodontal ligaments of the rats were studied by immunohistochemistry. The result showed that: magnetic field had dynamic effect and some promotional effect on recove?E F F E C T O F M A G N E T I C F I E L D O N C A L C I T O N I N G E N E- R E L A T E D P E P T I D E I N P E R I O D O N T A L L I G A M E N T S O F R A T S X. Chang , K. Qin and Y. L. Lu Orthodontic Department of Stomatology College , China Medical University , Shenyang 110001 , China Manuscript received 24 June 1999 In order to approach change of C G R P with tim e in periodontal liga m ents of rats in m agneticfield , m axillae of 28 Wistar rats of 6 7 weeks w ere placed in m agnetic fields of per m anentm agnets Nd 2 Fe4 B. Changes of C G R P with tim e in m axillary periodontal liga ments of therats were stu died by i m m unohistoche mistry . The result sho wed that : m agnetic field had dy na m ic effect an d so m e pro motional effect on recovering and reconstruction of the periodontaltissues in it . This provided a better theoretical evidence for clinical use of per m anent m agnets .

关键词: per m anent m agnet Nd 2 Fe4 B , null , null , null

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