Vapor Pressure Osmometry and Its Applications in the Osmotic Coefficients Determination of the Aqueous Monomer Glycol and Polymer Polyethylene Glycol Solutions at Various Temperature

Based on the principle and calibration of vapor pressure osmometer and its application in the thermodynamics of the aqueous solutions, the results on aqueous solution of monomer glycol,PEG200,PEG400,PEG1500 and PEG2000 over the different concentration range at various temperatures were reported.Using a linear least-square fitting routing,the osmotic coefficients were fitted by a simple polynomial equation.It was found that the relationship between the molar osmotic coefficients (Φ） and the molar concentration(c) of the solutions are in a quite good agreement with the fitted polynomial equation at various temperatures over the different concentration range.The experimental results also show that over the studied concentration range and at various temperatures,the concentration dependence of the molar osmotic coefficients of the aqueous solution systems with the solutes of PEG200,PEG400,PEG1500 and PEG2000 are totally presented in a rising tend,and their temperature dependence of the osmotic coefficients of the aqueous solution systems of the molar concentration exhibits their own regularities,respectively.The aqueous glycol solution system exhibits the properties of the dilute solution.     

Composite of Pt–Ru supported SnO2 nanowires grown on carbon paper for electrocatalytic oxidation of methanol

Platinum–ruthenium (Pt–Ru) nanoparticles were successfully deposited, for the first time, on the surface of SnO₂ nanowires grown directly on carbon paper (Pt–Ru/SnO₂ NWs/carbon paper) by potentiostatic electrodeposition method. The resultant Pt–Ru/SnO₂ NWs/carbon paper composites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The electrocatalytic activities of these composite electrodes for methanol oxidation were investigated and higher mass and specific activities in methanol oxidation were exhibited as compared to Pt–Ru catalysts deposited on glassy carbon electrode.     

多值函数在复变函数中的应用

通过讨论初等多值函数的单值解析分枝问题,重点研究了初等多值函数在复变函数中的具体应用.     

系数为LR-型模糊数的模糊线性最小二乘回归

针对输入、输出以及系数为LR-型模糊数的情况,建立模糊线性回归模型,提出该模型的最小二乘估计以及模型性能评价方法。当输入、输出以及系数都退化为精确值时,该估计退化为经典的最小二乘估计。该方法不仅适用于三角模糊数,也适用于其它LR-型模糊数(如指数型模糊数)。数值模拟表明,该方法的拟合效果较好。     

First total synthesis of （±）-abyssinoflavanone V

The total synthesis of （±）-abyssinoflavanone V was first achieved through C-prenylation, selective protection of phenolic hydroxyl group, aldol condensation, cyclization and deprotection starting from cheap 4-hydroxybenzaldehyde and 2,4,6- trihydroxyacetophenone, with total yield 24%. All structures of new compounds were confirmed by IR, 1^H NMR and MS.     

Three‐dimensional numerical simulation of compound meandering open channel flow by the Reynolds stress model

Turbulent flow in a compound meandering open channel with seminatural cross sections is one of the most complicated turbulent flows as the flow pattern is influenced by the combined action of various forces, such as centrifugal force, pressure, and shear stresses. In this paper, a three‐dimensional (3D) Reynolds stress model (RSM) is adopted to simulate the compound meandering channel flows. Governing equations of the flow are solved numerically with finite‐volume method. The velocity fields, wall shear stresses, and Reynolds stresses are calculated for a range of input conditions. Good agreement between the simulated results and measurements indicates that RSM can successfully predict the complicated flow phenomenon. Copyright © 2008 John Wiley & Sons, Ltd.     

沙漠砂混凝土动态力学性能实验研究

采用直锥变截面式Φ74mm分离式霍普金森压杆,对不同替代率沙漠砂混凝土进行冲击压缩实验,得到了不同替代率沙漠砂混凝土在不同应变率下的应力应变曲线。分析应变率对沙漠砂混凝土峰值应力、峰值应变和比能量影响,揭示了沙漠砂替代率对沙漠砂混凝土峰值应力影响规律,并对沙漠砂混凝土动态破坏模式进行研究。研究表明:随着应变率增加,沙漠砂混凝土峰值应力、强度增强因子、比能量和峰值应变逐渐增大;在同一应变率下,随着替代率增加,沙漠砂混凝土峰值应力逐渐减小。本文研究结果可为沙漠砂在工程中的应用提供指导和借鉴。     

4-甲基咪唑磁性表面分子印迹聚合物的制备及其应用

以4-甲基咪唑(4-MI)为模板分子,甲基丙烯酸(MAA)为功能单体,利用Fe₃O₄磁性纳米微球制备了具有特异性识别能力的磁性表面分子印迹聚合物(MIP),并用红外光谱(FT-IR)、X-射线衍射(XRD)、透射电子显微镜(TEM)和振动样品磁强计(VSM)对聚合物进行了表征,结果显示磁性载体表面包覆了分子印迹聚合物薄层。用紫外分光光度法对4-MI与MAA的相互作用进行了分析,结果表明主客体主要存在形式为1个4-MI被1个MAA所包围。通过紫外分光光度法对磁性印迹聚合物的吸附性能进行了研究,静态吸附平衡实验和Scatchard分析结果表明Fe₃O₄@(4-MI-MIP)中存在两类不同的结合位点,最大吸附量分别为40.31 mg/g和23.07 mg/g,平衡解离常数分别为64.85 mg/L和30.41 mg/L。动力学研究表明准二级动力学方程能较好地拟合动力学实验结果,该过程符合准二级动力学模型。该磁性印迹聚合物应用于环境水样中4-MI的吸附,取得了较满意的结果。     

反式白藜芦醇双功能单体印迹固相萃取柱的制备及应用

采用自组装技术,分别以β-环糊精和甲基丙烯酸为功能单体,反式白藜芦醇为模板分子,乙二醇二甲基丙烯酸酯为交联剂,制备了一种双功能单体印迹聚合物。 并将其作为固相萃取材料萃取红酒和白酒酒样中的反式白藜芦醇。 结果表明,与单功能印迹材料和非印迹材料相比,这种双功能单体印迹材料具有更高的吸附容量和选择性;结合高效液相色谱,建立了酒样中反式白藜芦醇浓度的检测方法。 该方法的线性范围在0.003~2 mg/L,红酒的回收率在87.9%~93.2%,白酒的回收率在89.3%~91.2%,检测限为0.001 mg/L。     

Rheological properties of styrene–butadiene rubber filled with electron beam modified surface treated dual phase fillers

The rheological properties of styrene–butadiene rubber (SBR) loaded with dual phase filler were measured using Monsanto Processability Tester (MPT) at three different temperatures (100°C, 110°C and 130°C) and four different shear rates (61.3, 306.3, 613, and 1004.5 s⁻¹). The effect of electron beam modification of dual phase filler in absence and presence of trimethylol propane triacrylate (TMPTA) or triethoxysilylpropyltetrasulphide (Si-69) on melt flow properties of SBR was also studied. The viscosity of all the systems decreases with shear rate indicating their pseudoplastic or shear thinning nature. The higher shear viscosity for the SBR loaded with the electron beam modified filler is explained in terms of variation in structure of the filler upon electron beam irradiation. Die swell of the modified filler loaded SBR is slightly higher than that of the unmodified filler loaded rubber, which is explained by calculating normal stress difference for the systems. Activation energy of the modified filler loaded SBR systems is also slightly higher than that of the control filler loaded SBR system.