环氧树脂/聚氧化乙烯共混物及其与硫氰化钠络合物的结构研究(Ⅰ)

对不同分子量聚氧乙烯(PEO)以不同比例与双酚A二缩水甘油醚型环氧树脂(ER)制得的交联共混物ER/PEO,以及再与NaSCN络合后的产物用WAXD,SAXS,DSC和SEM等方法进行了研究,结果表明:随着ER含量的增加,ER/PEO共混物由晶态转为非晶态。ER/PEO属单斜晶系;与NaSCN络合后,体系结晶性变差。ER/PEO-NaSCN属三斜晶系,其长周期比相应ER/PEO交联共混物的长周期值大。EP的加入使非晶层增厚,结晶片层变薄,长周期值增加。     

基于启发式变量筛选方法研究与雌激素β受体结合的化合物结构与活性之间的关系

雌激素类化合物由于其对人和野生动物健康的负面影响而受到广泛关注.雌激素受体存在两种亚型(ERα和ERβ),化合物与两种受体亚型在结合活性和化合物结构特征方面存在差异.以31种与雌激素β受体亚型(ERβ)结合的化合物为研究对象,采用启发式变量筛选方法,从1524个变量中筛选出5个与化合物活性(lgRBA)最相关的变量,然后采用多元线性回归(MLR)建立最佳预测模型.模型相关性显著,而且具有良好的稳健性和预测能力(r2=0.829,q2LOO=0.742,r2pred=0.772,q2ext=0.724,RMSEE=0.395).同时揭示了影响化合物与ERβ受体结合的配体化合物分子的结构特征,并对模型的应用域进行了研究.     

电化学还原预处理对BiVO_4薄膜电极光电化学氧化水性能的提高

在酸性水溶液中(pH=2.0),采用电化学还原(ER)方法对BiVO4薄膜电极进行预处理,并探讨了其对薄膜电极光电化学氧化水性能的影响.结果表明,这种预处理可显著提高电极的光电化学氧化水的性能,且具有良好的光电化学稳定性.利用扫描电子显微镜、X射线衍射、拉曼光谱、光电子能谱、紫外-可见漫反射光谱、荧光光谱、电化学阻抗谱及Mott-Schottky等方法对ER处理前后的电极进行了表征.结果表明,ER预处理使电极粗糙度增大,表面积增大约1.4倍;电极材料的晶型无明显变化,但V—O对称伸缩振动略有红移;表面Bi,V和O结合能变小,Bi3+部分被还原,Bi/V原子比增大;ER处理导致电极平带电位负移,光生载流子在薄膜电极/溶液界面转移速率加快,表面复合速率降低.这些变化和表面积增加是BiVO4电极光电化学性能提高的主要原因.     

3D-QSAR and docking studies of estrogen compounds based on estrogen receptor β

Close attention has been paid to estrogen compounds because these chemicals may pose a serious threat to the health of humans and wildlife. Estrogen receptor (ER) exists as two subtypes, ERα and ERβ. The difference in amino acids sequence of the binding sites of ERα and ERβ might lead to a result that some synthetic estrogens and naturally occurring steroidal ligands have different relative affinities and binding modes for ERα and ERβ. In this investigation, comparative molecular similarity indices analysis...     

应用于AGV自动导引车的快速充电系统

设计建立一种用于AGV自动导引车镍氢动力蓄电池的快速充电系统,该系统在充电过程中能实时监测蓄电池组的各个运行参数,完成数据运算并逻辑判断、控制充电过程至其结束,并利用去极化放电脉冲提高充电效率.     

光谱型电化学发光定量分析进展

电化学发光(electrochemiluminescence, ECL)是一种将电化学分析和化学发光分析相结合的现代分析技术,已在多个领域得到广泛应用. ECL辐射与电化学过程密切相关,其辐射强度通常伴随电化学反应的进行而变化,导致难以采用波长扫描方式准确采集ECL光谱.以点式光电转换元件——光电倍增管(PMT)作为检测器的传统ECL分析仪通常采用摒弃色散装置的构造设计,只能开展光强型ECL分析.采用色散装置与面阵/线阵光电转换元件相结合方式构建曝光成像摄谱型ECL检测装置,发展光谱型ECL分析技术,能够推动ECL光谱学及其分析应用的研究.本文在概述ECL检测装置发展历史的基础上,综述了光谱分辨型ECL定量分析新体系、新技术和新装置的研究进展,展望了光谱分辨型ECL定量分析的前景及相关仪器技术的产业化和国产化途径.     

钠型斜发沸石Na+-K+离子交换特性研究(Ⅱ)--过程传质模型及动力学特性研究

利用浅床实验法研究查明了钠型斜发沸石Na -K 离子交换过程以液膜扩散为主的控制机理,依据传质膜理论,推导出液膜控制下的离子交换传质速率模型,并测定了离子交换动力力学曲线和过程传质系数.研究结果表明:钠型斜发沸石Na -K 离子交换速率与溶液流速、温度和溶液的K 浓度成正比,与溶液粘度和沸石粒径成反比,过程总传质系数的模型计算值 与实验值拟和较好.     

Quantitative structure-activity relationship of compounds binding to estrogen receptor β based on heuristic method

Estrogen compounds may pose a serious threat to the health of humans and wildlife.The estrogen receptor (ER) exists as two subtypes,ERβ and ERβ.Compounds might have different relative affinities and binding modes for ERβ and ERβ.In this study,the heuristic method was performed on 31 compounds binding to ERβ to select 5 variances most related to the activity (LogRBA) from 1524 variances,which were then employed to develop the best model with the significant correlation and the best predictive power (r2 = 0.8...     

氧化锌薄膜/锡掺杂玻璃光波导元件及其对氯苯的气敏性研究

建立了玻璃光波导气敏元件检测氯苯气体的方法.采用浸渍-提拉法将ZnO敏感膜固定在锡掺杂玻璃光波导表面,研制出了检测氯苯气体的ZnO薄膜/锡掺杂玻璃光波导气敏元件,并用该玻璃光波导气敏元件对挥发性有机气体进行了检测.实验结果表明,在室温下,气敏元件对氯苯气体有明显的响应,而对相同浓度的其它挥发性有机气体的响应相对较小,对...     

高效液相色谱法分析雌激素受体的研究

雌激素受体(ER)测定方法及灵敏度问题早已引起临床医学家的关注。七十年代,国外采用饱和活性炭吸附法(DCC)测ER。DCC法简便但不精确,更不能区分受体亚型。蔗糖密度梯度离心法(SDGC)虽能克服DCC法的缺陷,但要求220,000g×16h的离心,受体部分失活降解,不可能作为常规分析用。国外于八十年代开始用HPLC分析ER。本文用大鼠子宫做实验材料,建立了排阻层析HPLC分析ER的方法,并对人子宫内膜及腺癌、乳腺癌组织中的ER做了分析。     

聚2,3—二硫代吩噻嗪的电流变性质研究

聚２，３－二硫代吩噻嗪的电流变性质研究肖深初（湖南化工研究院长沙４１０００７）林源斌申东升王安民朱礼仁（湘潭大学化学系湘潭４１１１０５）关键词电流变流体电流变性质有机半导体中图分类号Ｏ６３１．２１电流变学（Ｅｌｅｃｔｒｏｒｈｅｏｌｏｇｙ）是研究在电场...     

The influence of intercalation rate and degree of substitution on the electrorheological activity of a novel ternary intercalated nanocomposite

Kaolinite/dimethylsulfoxide (DMSO)/carboxymethyl starch (CMS) ternary nanocomposites were prepared according to the combination of intercalation and solution reaction. The results show that the intercalation rate (IR) of kaolinite in the ternary composite is adjusted by changing the mass rate, and the basal spacing of kaolinite was swelled from 0.715 to 1.120 nm. At the suitable component ratio of ternary nanocomposite, the optimum electrorheological (ER) effect can be attained. It is apparent that the notable ER effect of ternary ER fluid was attributed to the prominent dielectric property of the ternary nanocomposite electrorheological fluids (ERF), which is closely associated with the IR. With the increase of degree of substitution, the ER effect of ternary composite ERF is enhanced.     

电流变阻尼器的抗冲击性能研究

从理论和试验两个方面研究了所设计的电流变阻尼器在大冲击下的抗冲击性能,分析了电流变液性能与阻尼器结构参数对抗冲击性能的影响.认为采用高性能的电流变液体及改变结构参数,都可以使电流变阻尼器的高速缓冲性能提高.电流变液流速对电流变液的屈服应力影响显著,其值随流速的增加按指数规律减小.从定性、定量两个方面分析了电流变阻尼器作为阻尼器效果不明显的原因为:由电流变效应引起的阻尼力在整个液压阻力中所占比例太小,不能通过改变电压来使液压阻力具有很大的调节可控范围.     

PERCOLATION TRANSITION IN ELECTRORHEOLOGICAL FLUIDS

The electric conductivity, dynamic modulus and yield stress of the developed electrorheolo-gical fluid (ERF) are measured at different volume fraction and different electric field strengthusing a modified Rheometrics Mechanical Spectrometer (Model 605). The percolation theory isintroduced to explain electrorheological effect and found that the ERF′s have the similarpercolated network structure as that of other ordinary suspensions with a critical volume fractionvalue independent of electric field strength. A master curve of dimensionless modulus againstdimensionless volume fraction is obtained. which shows that the essence of ER phenomenonactually is one kind of the second ofder phase transition.     

Electrorheological effect of carbonaceous materials with hierarchical porous structures

Carbonaceous materials with different hierarchical porous structures for electrorheological (ER) dispersed phase have been synthesized by carbonization of as-prepared starch/silica precurser at different temperatures. The N₂ adsorption isotherms show that Cmeso-700 and Cmeso-500 particles have the BET surface areas of 1028 and 603 m² g⁻¹, respectively. They both have the mesoporous pores with size of about 4.6 nm and the microporous pores (1.1 and 1.5 nm, respectively). The BET surface areas and C/O atomic ratio of porous carbon materials can be increased with the carbonization temperatures. The rheological measurements indicate that the Cmeso-700 and Cmeso-500 ERF have the better ER effect resulted from their hierarchical porous structures. The shear stress of Cmeso-700 ERF is 900 Pa at 1000 s⁻¹ under 3 kV mm⁻¹, which is almost 4.5 times larger than that of Cmicro-350 ERF. The mesoporous carbon ERFs also show the better sedimentation stability than microporous carbon ERFs. The different ER effect of carbonaceous particles may derive from their different dielectric polarization property induced by the hierarchical porous structures.     

Electrorheological properties of poly(linear trans-quinacridone)-based suspensions

Ladder-like polymer poly(linear trans-quinacridine) (polyquin (2,3-b) acridine-7,14(5,12) dione, PTQA) was synthesized and identified. Anhydrous electrorheological fluid (ER fluid, ERF) with PTQA as dispersed particle and bromodiphenylmethane (BDPM) as dispersing medium were prepared; the electrorheological properties were studied. The temperature effect of PTQA suspensions was also discussed. The results showed that PTQA suspensions in BDPM performed excellent ER activity; at room temperature, the yield stress of the suspension with 30 wt.% of particles was up to 6.0 kPa (3.0 kV/mm). The shear stress increased with the rise in temperature, and the temperature effect was enhanced at higher temperature range. The differences of electrorheological properties between PTQA-based ERF and polyquin(2,3-b) acridine-12,14(5,7) dione-based ERF were attributed to the molecular structural regularity of the polymer.     

A new approach of enhancing the shear stress of electrorheological fluids of montmorillonite nanocomposite by emulsion intercalation of poly-N-methaniline

Poly-N-methaniline/montmorillonite (PNMA-MMT) nanocomposite particles with high dielectric constant as well as suitable conductivity were synthesized by an emulsion intercalation method and characterized by FT-IR, XRD, and TEM spectrometry, respectively. The electrorheological (ER) properties of the suspensions of PNMA-MMT particles in silicone oil (20 wt%) were investigated under DC electric fields. It was found that the shear stress of poly-N-methaniline/montmorillonite electrorheological fluid (ERF) is 6.0 kPa in 3 kV/mm (74.5 s(-1)), which is 3.6 times that of electrorheological fluid at zero field, and also much higher than that of pure poly-N-methaniline (PNMA) and montmorillonite (MMT). In the range of 10-90 degrees C, the shear stress changes slightly with the temperature. The sedimentation ratio of PNMA-MMT ERF was about 97% after 60 days. Furthermore, the dielectric constant of PNMA-MMT nanocomposite was increased 3.74 times that of PNMA and 1.99 times that of MMT at 1000 Hz, the dielectric loss tangent also increased about 1.58 times that of PNMA. It is apparent that the notable ER effect of PNMA-MMT ER fluid was attributed to the prominent dielectric property of the poly-N-methaniline/montmorillonite nanocomposite particles.     

平行平板间电流变液非零压力梯度Couette流动的稳定性分析

采用Rajagopal和Wineman所提出本构方程,对电流变液在二维平行平板间非零压力梯度Couette流动的线性稳定性问题进行研究.通过分析和数值计算发现,任何壁面运动都将使流动稳定性增强.在外加电场存在的情况下,电流变液效应也将使流动稳定性增强.     

In situ sol-gel preparation of polysaccharide/titanium oxide hybrid colloids and their electrorheological effect

A new type of organic/inorganic hybrid colloid, made of modified carboxylmethyl starch (CMS) and titanium oxide (TiO(2)), was synthesized by an in situ sol-gel technique. IR spectra analysis shows strong a interaction of functional groups between two components, whose dispersion is almost at the molecular level. Due to the highly active surfaces hybrid particles and their characteristic dielectric behavior in accordance with the previous theoretic calculation, the suspensions of hybrids in silicone oil display a remarkable ER effect. The static yield stress can be above 20 kPa (shear rate 5 S(-1)) under a direct current field of 4 kV/mm at room temperature, much higher than that of simple blends of starch and titanium dioxide. In the meanwhile, the temperature dependence and sedimentation stability were optimized. Based on existing experimental results, we propose that dielectric properties and surface (interface) activity are two necessary conditions fulfilling the requirement of high ER activity. The combination of both factors may effectively reduce the activation energy needed for ERF restructuring.