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MEI结构单元的介孔Ti-HMS-1的合成、表征及催化氧化性能

马乾志 , 郭杨龙 , 王艳芹 , 郭耘 , 张志刚 , 卢冠忠

无机材料学报 doi:10.3321/j.issn:1000-324x.2007.05.033

采用TS-1前驱体作硅源和钛源,以十二胺为模板剂,在中性和室温条件下合成了介孔含钛分子筛Ti-HMS-1.采用XRD、TEM、低温N2吸附、FT-IR和UV-Vis等方法对合成的分子筛进行了表征;以苯乙烯的催化氧化反应为模型反应,考察了合成的Ti-HMS-1的催化氧化性能.结果表明,Ti-HMS-1具有"worm-like"介孔结构,但长程有序度较低,孔壁部分含有MFI的次级结构单元,在373K沸水中水煮50h后,Ti-HMS-1仍能较好地保持原有的介孔结构,表明Ti-HMS-1具有较高的水热稳定性.进入分子筛骨架的钛原子为催化剂的活性中心,对于苯乙烯氧化反应,具有较高的催化活性,对产物的选择性与Ti-HMS接近.

关键词: Ti-HMS-1分子筛 , 合成 , 表征 , 苯乙烯氧化

Molecular dynamics study of atomic transport properties in rapidly cooling liquid copper

Journal of Chemical Physics

Based on Mei's embedded atom model [Mei , Phys. Rev. B 43, 4653 (1991)] molecular dynamics simulations have been performed to investigate the rapidly cooling processes of Cu. The atomic transport property, namely the self-diffusion coefficient, is computed in the liquid state, and the results near the melting point of Cu are in good agreement with experimental data and other computational values. The atom diffusion movements during the long period of relaxation have been also studied around the solidification temperature T-c. To describe the complex microstructural evolutions during the rapidly cooling processes and the long relaxation processes, the pair correlation function and the pair analysis technique are used. It is demonstrated that the crystallization of amorphous Cu is caused by the atomic diffusion. (C) 2004 American Institute of Physics.

关键词: transition-metals;computer-simulation;supercooled-liquid;model;fcc;potentials;diffusion

1998 COMPREHENSIVE TABLE OF CONTENTS

中国腐蚀与防护学报

N。1Atmospheric Corrosivlty for Steels………………………………………………… .LIANG Caideng HO[I i。-tat(6)Caustic Stress Corrosion Cr。king of Alloy 800 Part 2.The Effect of Thiosul执e……………………………………… KONG De-sheng YANG Wu ZHAO Guo-zheng HUANG De.ltL。ZHANG Yu。。he CHEN She。g-bac(13)SERS slid E16CttOCh6iniC81 Stlldy Of Illhibit1Oli M6ch&tllsth Of ThlollY68 Oil ITOll ID H....

关键词:

NiO/FeCo磁性多层膜的高频磁性

李玉伟 , 陈继红 , 唐东明 , 张豹山 , 鹿牧 , 陆怀先

功能材料与器件学报 doi:10.3969/j.issn.1007-4252.2010.02.011

制备了一系列具有铁磁/反铁磁交换偏置作用的[NiO/Fe65Co35]10多层膜,使用振动样品磁强计(VSM)测量了样品的静磁参数,利用微带线法测量了样品4GHz-10GHz的磁谱,首次制备并测得了自然共振频率(fr)在6GHz以上,最高到f=9.6GHz的薄膜样品.结果表明交换偏置场(Hex)、各向异性场(Hua)、以及矫顽力(Hc)随铁磁层厚度(tFM)增大而减小;基于Landau-Lifishitz (L-L)方程对静磁参量和磁谱进行了比较,发现样品自然共振频率较L-L方程计算值偏大30%以上.

关键词: 铁磁 , 反铁磁 , 交换偏置场 , 各向异性场 , 交换耦合能密度 , 自然共振频率

Hardness of T-carbon: Density functional theory calculations

Physical Review B

We reconsider and interpret the mechanical properties of the recently proposed allotrope of carbon, T-carbon [Sheng et al., Phys. Rev. Lett. 106, 155703 (2011)], using density functional theory in combination with different empirical hardness models. In contrast with the early estimation based on Gao et al.'s model, which attributes to T-carbon a high Vickers hardness of 61 GPa comparable to that of superhard cubic boron nitride (c-BN), we find that T-carbon is not a superhard material, since its Vickers hardness does not exceed 10 GPa. Besides providing clear evidence for the absence of superhardness in T-carbon, we discuss the physical reasons behind the failure of Gao et al.'s and Simunek and Vackar's (SV) models in predicting the hardness of T-carbon, residing in their improper treatment of the highly anisotropic distribution of quasi-sp(3)-like C-C hybrids. A possible remedy for the Gao et al. and SV models based on the concept of the superatom is suggested, which indeed yields a Vickers hardness of about 8 GPa.

关键词: superhard rhenium diboride;elastic-constants;ambient-pressure;metal;borides;crystals;diamond;search;boron

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

腐蚀科学与防护技术

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

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