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Threading dislocation density comparison between GaN grown on the patterned and conventional sapphire substrate by high resolution X-ray diffraction

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Science china(Physics,Mechanics & Astronomy) 2010年第3期53卷 465-468页

作者： ZHANG YuChao1, XING ZhiGang2. MA ZiGuang2. CHEN Yao2. DING GuoJian2. XU PeiQiang2. DONG ChenMing3, CHEN Hong2.& LE XiaoYun1 1 School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100190, china 2.Renewable Energy Laboratory, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, china 3 School of Information and Communication, {2. Polytechnic University, {2. 300160, china Beihang University School of Physics and Nuclear Energy Engineering Beijing China (GRID:grid.64939.31) (ISNI:***) Chinese Academy of Sciences Renewable Energy Laboratory Institute of Physics Beijing China (GRID:grid.9227.e) (ISNI:***) tianjin Polytechnic University School of Information and Communication Tianjin China (GRID:grid.410561.7)

GaN epifilms are grown on the patterned sapphire substrates (PSS) (0001) and the conventional sapphire substrates (CSS) (0001) by metal-organic chemical vapor deposition (MOCVD) using a novel two-step growth. High resolution X-ray diffraction (HR-XRD) is used to investigate the threading dislocation (TD) density of the GaN epifilms. The TD density is calculated from the ω-scans full width at half maximum (FWHM) results of HR-XRD. The edge dislocation destiny of GaN grown on the PSS is 2.7×108 cm-2. which is less than on the CSS. This is confirmed by the results of atomic force microscopy (AFM) measurement. The lower TD destiny indicates that the crystalline quality of the GaN epifilms grown on the PSS is improved compared to GaN epifilms grown on the CSS. The residual strains of GaN grown on the PSS and CSS are compared by Raman Scattering spectra. It is clearly seen that the residual strain in the GaN grown on PSS is lower than on the CSS.

关键词： GaN patterned sapphire substrate threading dislocation XRD

STUDY ON THE CATALYTIC REACTION OF ACETONE TO DIACETONE ALCOHOL

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Chinese Journal of Catalysis 1996年第5期 121-126页

作者： Sun Hongwei, He Fei, Xu Genhui *, Ma Xinbin (Department of chemical Engineering, tianjin University, tianjin 300072.

ＳＴＵＤＹＯＮＴＨＥＣＡＴＡＬＹＴＩＣＲＥＡＣＴＩＯＮＯＦＡＣＥＴＯＮＥＴＯＤＩＡＣＥＴＯＮＥＡＬＣＯＨＯＬＳｕｎＨｏｎｇｗｅｉ，ＨｅＦｅｉ，ＸｕＧｅｎｈｕｉ＊，ＭａＸｉｎｂｉｎ（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｃ... 详细信息

ＳＴＵＤＹＯＮＴＨＥＣＡＴＡＬＹＴＩＣＲＥＡＣＴＩＯＮＯＦＡＣＥＴＯＮＥＴＯＤＩＡＣＥＴＯＮＥＡＬＣＯＨＯＬＳｕｎＨｏｎｇｗｅｉ，ＨｅＦｅｉ，ＸｕＧｅｎｈｕｉ＊，ＭａＸｉｎｂｉｎ（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｃａｌＥｎｇｉｎｅｒｉｎｇ，Ｔｉａｎ...

关键词： Anion exchange resin Aldol condensation Acetone Diacetone alcohol

Preparation and Characterization of Collagen-GAGs Bioactive Matrices for Tissue Engineering

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Journal of Materials Science & Technology 2001年第5期17卷 495-500页

作者： Hongyi YANG and Qiqing ZHANG Institute of Biomedical Engineering, Chinese Academy of Medical Science, tianjin 300192. china Inst. of Biomed. Eng. Chinese Acad. of Med. Sci. Tianjin 300192 China

Collagen materials were crosslinked by 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) in the presence of chondroitin sulfate (CS), one of glycosaminoglycans (GAGS). PVA and chitosan were also blended with collagen. The physical and chemical properties of the matrices were characterized by SEM, DSC, and ESCA. L92. cells were implanted on the matrices to show the cytotoxic and the biological characters of the materials. The results indicate that EDC is an effective and non-cytotoxic cross-link reagent, which can replace the common dialdehyde reagent. The attachment of CS can improve the stability of collagen and accelerate cell growth. The addition of PVA can prepare porous matrices with smaller bore size. There are reactions between the chitosan and collagen, and the composite has good biological character. The presence of chitosan can also increase the amount of incorporated CS.

关键词： Preparation and Characterization of Collagen-GAGs Bioactive Matrices for Tissue Engineering PVA EDC CS

Phenol Tert-Butylation Catalyzed by Zeolite H-Mordenite

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Transactions of tianjin University 2005年第2期11卷 89-91页

作者：韩森李振花张悝 Key Laboratory for Green chemical Technology of Education Ministry of china School of Chemical Engineering and Technology Tianjin University Tianjin 300072 China

Para-tert-butyl phenol (p-TBP) and 2.4-di-tert-butyl phenol (2.4-DTBP) are widely used for the preparation of antioxidants. Zeolite catalysts showed good performance for the synthesis of p-TBP and 2.4-DTBP. In this work, zeolite H-mordenite (HM) catalyst was prepared and the alkylation of phenol with tert-butyl alcohol over zeolite HM catalyst was investigated at different reaction conditions. It is found that increasing temperature enhances the selectivity to p-TBP and the optimum reaction temperature for phenol conversion is 438 K. Increasing flow rate decreases phenol conversion apparently while the selectivity to p-TBP has a little increase. The suitable tert-butyl alcohol/phenol molar ratio is 2. Lower alcohol/phenol molar ratios are beneficial to p-TBP while higher ones are helpful for producing 2.4-DTBP.

关键词： phenol tert-butyl alcohol zeolite H-mordenite (HM) alkylation

NUMERICAL SIMULATIONS OF THE HYDRAULIC CHARACTERISTICS OF SIDE INLET/OUTLETS

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Journal of Hydrodynamics 2011年第1期23卷 48-54页

作者： YE Fei GAO Xue-ping North china University of Water Conservancy and Electric Power Zhengzhou 450011 China School of Civil Engineering Tianjin University Tianjin 300072 China

The hydraulic characteristics at the side inlet/outlet of pumped storage plants is studied by numerical simulations,covering the flow distribution,head loss,vortex,and *** on the physical model test,the realizable k-εturbulence model is used in the 3-D simulation of the side inlet/outlet.A new scheme is suggested to obtain the uneven flow distribution over three branch *** variation of the free surface with the reservoir water level under the pumped condition is simulated,with results consistent with the experimental results.

关键词： hydraulic characteristics side inlet/outlet pumped storage plant numerical simulation realizable k-εturbulence model

Modeling the Migration of Soluble Methanol in Unsaturated Soil Zone

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Pedosphere 2007年第3期17卷 366-372页

作者： LI Hong LI Xin-Gang HUANG Guo-Qiang JIANG Bin School of chemical Engineering and Technology Tianjin University Tianjin 300072 （China） National Engineering Research Center for Distillation Technology Tianjin 300072 （China）

A combined model of solute transport and water flow was developed to simulate the migration of methanol, a soluble organic chemical, in unsaturated soil zone. The solute transport equation considered convective-dispersive transport in the liquid phase as well as diffusion in the gas phase. The effect of rainfall and evapotranspiration on transport was considered at the boundary conditions of the governing equations. Data on the characteristics of a loam soil and the climatic conditions in southern California were also introduced to compare the results with those from a study in the USA in which the profiles of methanol distribution and water content in the soil zone at different times had been depicted. This comparison showed that there was good agreement between the two studies. The results showed that methanol contamination reached a depth of about 2.0 cm after 8 760 h. In contrast, if rainfall and evapotranspiration were not considered, the depth was only about 140 cm. The model therefore confirmed that rainfall strongly affected solute transport.

关键词： evapotranspiration methanol rainfall solute transport model

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底物的溶解对甾体微生物羟化反应的影响

天津大学学报（自然科学与工程技术版） 2004年第11期37卷 941-944页

作者：李晓静冯霞阳葵天津大学化工学院天津300072 天津大学理学院天津300072

底物分子的引入会导致表面活性剂PSE水溶液CMC值增大.表面活性剂与超声处理配合使用可以有效地增强底物的溶解.在表面活性剂底物水体系中,高强度、长时间的超声处理对底物的溶解不利.超声波(强度为6.2./cm2.时间为10min)与表面活性剂P... 详细信息

底物分子的引入会导致表面活性剂PSE水溶液CMC值增大.表面活性剂与超声处理配合使用可以有效地增强底物的溶解.在表面活性剂底物水体系中,高强度、长时间的超声处理对底物的溶解不利.超声波(强度为6.2./cm2.时间为10min)与表面活性剂PSE(质量分数为0.015%)的配合使用可以降低表面活性剂用量,在增强甾体底物溶解性的同时,能够更好地维持转化阶段菌体酶的活性,有效地实现底物转化.

关键词：甾体化合物微生物转化表面活性剂超声波溶解

Analysis of regulatory architectures in BST

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Progress in Natural Science:Materials International 2003年第12期 34-39页

作者： BIAN Fuping 1,2. *, LIANG Min 1,2. and ZHAO Xueming 3(1. Department of Mathematics, School of Science, tianjin University 2. Liu Hui Center for Applied Mathematics, Nankai University & tianjin University 3. School of {2. Engineering, tianjin University, tianjin 300072. china) Department of Mathematics，School of Science，tianjin University Liu Hui Center for Applied Mathematics，Nankai University & tianjin University School of chemical Engineering，tianjin University，tianjin 300072.china

Based on the data envelopment analysis (DEA) theory, the optimal pathway of metabolic reaction networks in biochemical systems is studied. After calculating the mixed integer linear programming (MILP) model given by Bailey et al. twice, the decision making units (DMU) and the prediction model of DEA are constructed, where the inputs are levels of manipulated parameters (enzyme) and outputs are concentrations of metabolites. When the metabolic networks are reconstructed, the data are obtained by calculating MILP framework twice and the optimal levels of the manipulated parameter at different regular loops are predicted, thus simplifying the calculations of Bailey’s.

关键词： metabolic reaction networks MILP the prediction model of DEA efficient DMU.

电场增强催化甲烷合成碳二烃催化剂影响研究(英文)

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燃料化学学报 2002年第2期30卷 97-102页

作者：王保伟许根慧天津大学一碳化工国家重点实验室

本研究提出了在常温、常压电场增强等离子体条件下甲烷直接转化合成碳二烃的洁净工艺 ,在不同的放电电压、放电功率、甲烷进料流量和不同的催化剂作用下 ,甲烷能够以不同的转化率和选择性转变为碳二烃。对影响甲烷转化率和碳二烃选择性... 详细信息

本研究提出了在常温、常压电场增强等离子体条件下甲烷直接转化合成碳二烃的洁净工艺 ,在不同的放电电压、放电功率、甲烷进料流量和不同的催化剂作用下 ,甲烷能够以不同的转化率和选择性转变为碳二烃。对影响甲烷转化率和碳二烃选择性的因素 :放电电压、放电功率、甲烷进料流量和催化剂进行了研究 ,对催化剂性能进行了比较 ,并探讨了反应机理。结果表明 ,适宜的工艺条件 :放电电压 2.0kV～ 4 0kV ;输入功率 :2.0W～ 4 0W ;合适的甲烷进料流量 :30mL/min～ 70mL/min。在该条件下 ,碳二烃的选择性可以达到 95 % ;催化剂对甲烷转化率的影响顺序为MnO2./Al2.O3 >Ni/Al2.O3 >MoO3 /Al2.O3 >Ni/NaY >Pd/ZSM 5 >Ni/H4Mg2.Si3 O4>Ni/ZSM 5 >Co/ZSM 5 >无催化剂。

关键词：甲烷碳二烯电场增强等离子体催化剂