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Acta Mechanica Sinica 2006年第5期22卷 425-432页

作者： lixing Zhou rongxian li Ruxu Du Department of Engineering Mechanics Tsinghua University Beijing 100084 China Shenzhen Research Institute Tsinghua UniversityShenzhen China Department of Automation and Computer Aided Engineering The Chinese University of Hong Kong Hong Kong China

There are contradicted opinions on whether bubbles enhance or reduce the liquid turbulence. In this paper, the effect of void fraction and inlet velocity on the bubble-liquid two-phase turbulence of the multiple bubble-liquid jets in a two-dimensional channel is studied by using the two-phase second-order moment turbulence model. The results confirm the phenomena observed in experiments and reported in references that at a low void fraction and low inlet velocities the bubbles enhance the liquid turbulence, whereas at a high void fraction and high inlet velocities the bubbles reduce the liquid turbulence.

关键词： Bubble-liquid flows Two-phase turbulence Second-order moment model

Experimental Study on the Characteristics of liquid Layer and Disturbance Waves in Horizontal Annular Flow

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Journal of Thermal Science 1999年第4期8卷 235-242页

作者： li Weidong Zhou Fangde li rongxian Zhou lixing Department of Engineering Mechanics Tsinghua UniversityBeijing 100084China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049China

The mechanism for transporting liquid from the bottom of the pipe to the top still to be established in the prediction of the film thickness distribution in horizontal annular two-phase flow. To resolve this issue, using five parallel-wire conductance probes, time records of local liquid film thickness at five circumferential positions were collected. The characteristics of circumferential liquid film thickness profiles and its variation with gas and liquid velocities were obtained. The basic features of probability distribution function, probability density function, auto-correlation, cross-correlation and power spectrum density function of the disturbance waves in angular flow were studied respectively. The characteristics of circumferential profiles of disturbance waves and its variation with gas and liquid velocities were presented.

关键词： two-phase flow annular flow liquid layer disturbance wares.

Self-assembly and drug delivery behaviors of a novel thermo-sensitive block glycopolymer

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Chinese Science Bulletin 2010年第36期55卷 4187-4196页

作者： CHEN liQiong ZHANG liMing CHEN JianJun YANG Jian li rongxian DSAMP Laboratory and PCFM Laboratory School of Chemistry and Chemical Engineering Sun Yat-sen University Guangzhou 510275 China Research Institute of Tsinghua University in Shenzhen Shenzhen 518057 China

A novel thermo-sensitive block glycopolymer based on peracetylated maltoheptaose (AcMH) and poly(2-ethyl-2-oxazoline) (PEtOz) was synthesized for the first time and characterized by hydrogen nuclear magnetic resonance (1H NMR) spectroscopy and gel permeation chromatograph (GPC) analyses. To obtain such a block polymer, the dihydroxyl poly(2-ethyl-2-oxazoline) homopolymer (OH-PEtOz-OH) was first synthesized by cationic ring-opening polymerization of 2-ethyl-2-oxazoline (EtOz), and then coupled with the peracetylated maltoheptaose having a free hydroxyl group at the reducing end (AcMH-OH) prepared from β-cyclodextrin. It was found that the obtained block polymer could self-assemble into nanosize spherical micelles with a distinct core-shell structure in aqueous solution triggered by its amphiphilic character without any organic solvent. The model drug indomethacin (IND) was efficiently loaded into the resultant polymeric micelles, which was confirmed by 1H NMR spectra, transmission electron microscope (TEM) and dynamic light scattering (DLS) techniques. The release behavior of IND loaded micelles was well in response to the environmental temperature change. It is suggested that the resulting micelles might be a potential targeted carrier for drug delivery.

关键词：自组装行为药物输送温敏凝胶渗透色谱仪透射电子显微镜嵌段聚合物胶束结构核磁共振光谱

Preparation of Styrene-acrylate Latex Used in Ultralow VOC Building Internal Wall Coating

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Journal of Wuhan University of Technology(Materials Science) 2008年第1期23卷 65-70页

作者：陈立军 WU Fengqin ZHUANG Xinyu YANG Jian li rongxian Department of Material Science and Engineering Tsinghua University Beijing 100084 China Research Institute of Tsinghua University in Shenzhen Shenzhen 518057China Shenzhen Novel Company Shenzhen 518054 China

Styrene-acrylate latex with high glass transition temperature （T）, low minimum film forming temperature（MFT） and good stability was prepared via core-shell emulsion polymerization. With semicontinuous process, high conversion rate of monomer and low gel rate were achieved. The weight ratio of core monomer to shell monomer was approximately 1.35. It is found that many factors such as emulsifiers, initiators, reaction temperature, pH value and polymerization technology have influences on the permormance of styrene-acrylate latex. The prepared latex was characterized by TEM and FTIR. The obtained latex with T of 20.57 ℃, MFT or5.0 ℃, and good stability, had good stability of film forming.

关键词： ultra-low VOC building internal wall coating styrene-acrylate latex core-shell emulsion polymerization

预测水平管气—液环状流周向液膜厚度分布的理论模型

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化工学报 2001年第3期52卷 204-208页

作者：李卫东 li rongxian 李荣先王跃社周芳德清华大学工程力学系 Department of Engineering Mechanics Tsinghua University 西安交通大学

针对水平环状流液膜厚度沿周向分布的不对称性, 用5组双平行电导探针测量了水平管内气液环状流沿周向的瞬态液膜厚度,得到了平均液膜厚度沿周向的分布规律.分析了液膜向上输送的机理.为更为准确地预测液膜厚度, 综合考虑了扰动波抽吸作... 详细信息

针对水平环状流液膜厚度沿周向分布的不对称性, 用5组双平行电导探针测量了水平管内气液环状流沿周向的瞬态液膜厚度,得到了平均液膜厚度沿周向的分布规律.分析了液膜向上输送的机理.为更为准确地预测液膜厚度, 综合考虑了扰动波抽吸作用机理、气体二次流机理及液滴沉降和携带机理; 通过量级比较和应力平衡的方法, 提出了一个预测液膜厚度沿周向分布的理论模型.数值模拟结果表明预测值与实验测量结果符合较好.

关键词：气-液两相流环状流液膜厚度水平管理论模型周向分布液体物料输送预测

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ZnO/Ag纳米复合材料光催化性能研究

稀有金属材料与工程 2007年第A02期36卷 299-302页

作者：孟阿兰岑伟李镇江李荣先青岛科技大学山东青岛266042 深圳清华大学研究院广东深圳518057

通过XRD、TEM测试研究了自制ZnO/Ag纳米复合材料的结构和形貌,通过UV检测确定了以该纳米复合材料为光催化剂,在不同条件下对甲基橙的光催化降解率。结果表明:与空气煅烧相比,真空煅烧所得纳米复合材料的光催化降解效果更好,且光催化降... 详细信息

通过XRD、TEM测试研究了自制ZnO/Ag纳米复合材料的结构和形貌,通过UV检测确定了以该纳米复合材料为光催化剂,在不同条件下对甲基橙的光催化降解率。结果表明:与空气煅烧相比,真空煅烧所得纳米复合材料的光催化降解效果更好,且光催化降解率随纳米复合材料用量增加而增大;甲基橙溶液的pH在5左右时,光催化降解率最高;H_2O_2浓度为0.9 g/L时,光催化降解率可达100%。

关键词： ZnO/Ag 纳米复合材料光催化降解甲基橙

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水平管内气液环状流液膜及扰动波特性

清华大学学报（自然科学版） 2000年第11期40卷 23-26页

作者：李卫东李荣先周力行清华大学工程力学系北京100084

针对重力引起的水平环状流液膜厚度沿周向分布的不对称性 ,用 5组双平行电导探针测量了周向 5个角度处的瞬态液膜厚度随时间的变化。分析了平均液膜厚度沿周向的分布及其随气、液折算速度的变化特性。运用时频分析方法研究了环状流扰动... 详细信息

针对重力引起的水平环状流液膜厚度沿周向分布的不对称性 ,用 5组双平行电导探针测量了周向 5个角度处的瞬态液膜厚度随时间的变化。分析了平均液膜厚度沿周向的分布及其随气、液折算速度的变化特性。运用时频分析方法研究了环状流扰动波信号的概率密度函数、概率分布函数、自相关函数、互相关函数以及功率谱密度函数的基本特征 ,揭示了扰动波的特性及其沿周向的频率分布规律。

关键词：气液两相流环状流扰动波水平管液膜厚度

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射流稀疏颗粒图像PIV算法应用

化工学报 2005年第7期56卷 1206-1208页

作者：虞建李荣先周力行清华大学航天航空学院北京100084

A comparison of three PIV algorithms: FFT-based cross-correlation (FFT-CC) method, direct cross-correlation (DCC) method, and minimum quadratic difference (MQD) method was performed by applying these methods to low number density PIV images obtained by the Japan Visualization *** results of the MQD method were better than those of the FFT-CC, but validated results of the FFT-CC method were better than those of the MQD method. Results of the DCC method were the *** was discrepancy between results of the same algorithm with different sizes of the interrogation *** mainly resulted from various amounts of matched particles of sub *** study could provide good reference to the selection of the algorithm and its parameters.(

关键词：颗粒图像测速(PIV) 最小平方差 FFT互相关直接计算相关系数射流稀疏颗粒图像

燃料环缝进口的丙烷-空气旋流扩散燃烧的LES-EBU和RANS-SOM模拟的比较

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化工学报 2006年第10期57卷 2278-2282页

作者：王文丽周力行李荣先清华大学航天航空学院北京100084

用Smagorinsky-lilly亚网格尺度湍流模型和EBU亚网格尺度湍流燃烧模型,对燃料环缝进口的丙烷-空气旋流湍流燃烧进行了大涡模拟(LES),并且用二阶矩(SOM)统观湍流燃烧模型进行了RANS模拟,将模拟所得统计平均的热态三个方向速度,湍流度,温... 详细信息

用Smagorinsky-lilly亚网格尺度湍流模型和EBU亚网格尺度湍流燃烧模型,对燃料环缝进口的丙烷-空气旋流湍流燃烧进行了大涡模拟(LES),并且用二阶矩(SOM)统观湍流燃烧模型进行了RANS模拟,将模拟所得统计平均的热态三个方向速度,湍流度,温度,丙烷、氧和CO2浓度分布和详细的实验数据对比.结果表明,LES-EBU大涡模拟的统计结果不如RANS-SOM模拟结果.因此,EBU亚网格尺度湍流燃烧模型有待改进.RANS-SOM模型可以进一步在预报工程中的旋流扩散燃烧中应用.

关键词：旋流燃烧大涡模拟二阶矩模型

工艺参数对合成ZnO/Ag纳米复合抗菌剂产率的影响

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稀有金属材料与工程 2007年第A02期36卷 293-295页

作者：李镇江郭锋孟阿兰李荣先梁开明青岛科技大学山东青岛266042 深圳清华大学研究院广东深圳518057

通过正交实验,研究了反应温度、反应时间、反应物配比对ZnO/Ag纳米复合抗菌剂合成产率的影响规律。获得了高产率合成ZnO/Ag纳米复合抗菌剂的优选工艺条件:反应温度为10～25℃,ZnSO_4与NH_4HCO_3的摩尔比为1:2～2.5,ZnSO_4与NH_4HCO_3的... 详细信息

通过正交实验,研究了反应温度、反应时间、反应物配比对ZnO/Ag纳米复合抗菌剂合成产率的影响规律。获得了高产率合成ZnO/Ag纳米复合抗菌剂的优选工艺条件:反应温度为10～25℃,ZnSO_4与NH_4HCO_3的摩尔比为1:2～2.5,ZnSO_4与NH_4HCO_3的反应时间为2.5～3 h,AgNO_3与NH_4HCO_3的摩尔比为1:1.5～2,反应时间为0.5 h,ZnO/Ag的产率超过98%。XRD、TEM和SAED结果表明:ZnO/Ag纳米复合抗菌剂为具有纤锌矿结构的ZnO和立方结构的Ag组成。粒径为15～25 nm,分散性较好。

关键词： ZnO/Ag 产率合成纳米复合抗菌剂