Pervaporation of organic liquid/ water mixtures through a novel silicone copolymer membrane

Polydimethylsiloxane-ladder like phenylsilsesquioxane copolymer as a novel membrane material has good film-forming ability, high mechanical properties and low swelling capacity. The copolymer membrane displays the permselectivity of organic liquid for the pervaporation of organic liquid/water mixtures. The pervaporation of aqueous solution of ethanol through the membrane has been investigated. High separation factor can be obtained in the range of low ethanol concentration. The flux of ethanol increases and the flux of water keeps constant as the concentration of ethanol in feed increases. The membrane shows good stability of separation at room temperature to 70℃. The comparison of the pervaporation behavior of the aqueous solutions of methanol, ethanol, 2-propanol, acetone, THF reveals that the magnitude of the separation factors and the fluxes increases in the following order: methanol相似文献   

Active transport of Ca2+ by an artificial photosynthetic membrane

Transport of calcium ions across membranes and against a thermodynamic gradient is essential to many biological processes, including muscle contraction, the citric acid cycle, glycogen metabolism, release of neurotransmitters, vision, biological signal transduction and immune response. Synthetic systems that transport metal ions across lipid or liquid membranes are well known, and in some cases light has been used to facilitate transport. Typically, a carrier molecule located in a symmetric membrane binds the ion from aqueous solution on one side and releases it on the other. The thermodynamic driving force is provided by an ion concentration difference between the two aqueous solutions, coupling to such a gradient in an auxiliary species, or photomodulation of the carrier by an asymmetric photon flux. Here we report a different approach, in which active transport is driven not by concentration gradients, but by light-induced electron transfer in a photoactive molecule that is asymmetrically disposed across a lipid bilayer. The system comprises a synthetic, light-driven transmembrane Ca2+ pump based on a redox-sensitive, lipophilic Ca2+-binding shuttle molecule whose function is powered by an intramembrane artificial photosynthetic reaction centre. The resulting structure transports calcium ions across the bilayer of a liposome to develop both a calcium ion concentration gradient and a membrane potential, expanding Mitchell's concept of a redox loop mechanism for protons to include divalent cations. Although the quantum yield is relatively low (approximately 1 per cent), the Ca2+ electrochemical potential developed is significant.     

阿特拉津在金纳米通道中的迁移特性研究

报道阿特拉津在圆柱形的金纳米通道的迁移特性．采用化学沉积法在聚碳酸酯滤膜的孔道里面沉积金,阿特拉津免疫原与载体蛋白形成的复合物通过金纳米通道时产生电流响应,阿特拉津免疫原、阿特拉津与抗体形成的复合物以及其他除草剂通过金纳米通道时产生的电流响应有着明显的不同．该传感器测定阿特拉津的线性范围是2．56×10-8～3．33×10-7mol／L．检测限可达1．70×10-10mol／L．传感器用于实际样品测定,结果满意．     

高梁根质膜K~+转运蛋白在人工脂质体上的活性重组

将高粱根质膜中K~+ -ATPase活性重组入人工脂质体中 ,并研究了脂蛋白体的性质。结果表明 ,脂蛋白体中脂和蛋白质浓度与离子转运活性呈正相关 ,当其含粗提大豆磷脂且脂 /蛋白比率为 3 5时 ,其K+ 转运活性最大。     

氨在中空纤维支撑液膜内的渗透系数

测定了氨在中空纤维支撑液膜中的渗透系数,并考察了渗透系数的影响因素.实验结果表明,氨在支撑液膜中的渗透系数p值随着载体浓度升高而增大,但变化趋势不大;料液pH值升高,渗透系数增大;反萃液pH值对渗透系数的影响存在最大值,在实验条件下,反萃液pH值为3时,渗透系数较大.比较煤油、癸醇和正庚烷3种膜溶剂,正庚烷作为膜溶剂渗透系数最大     

有机分子电子输运性质的研究

利用从头计算理论和弹性散射格林函数的方法,对有机分子1,4-苯二硫酚（benzene-1,4-dithiol）和对苯二甲氰（1,4-phenylene diisocyanide）的电子输运性质进行了理论研究．结果显示两种分子都具有电导的平台效应和电流的线性响应,但分子与电极的耦合程度不同,电流的开启位置和电导平台的宽度与高度也有明显的区别．     

液体有机物的干燥实验

分别用MgSO4、CaO、K2CO3对含饱和水的乙酸乙酯、乙醚、正丁醇进行干燥实验,比较了干燥剂用量的大小、现象的变化和干燥的效率。     

碱性阴离子交换膜燃料电池实验及数值模拟

针对碱性阴离子交换膜燃料电池(AEMFC)水管理开展了实验及数值模拟工作,使用Tokuyama A201膜制备并组装了实验室规模的AEMFC单电池,建立了一个基于质量守恒、组分守恒及电荷守恒的碱性阴离子交换膜燃料电池二维稳态等温模型,用于研究电池性能及内部水传输机理。通过模型计算分析电池性能及内部水传输和水分布情况,结果表明:计算预测得到的特定参数下的极化曲线趋势与单电池测试的数据吻合良好;电流密度增加会增大水从阳极到阴极的净通量,有利于阴极反应的进行;电池两极均需进气加湿,提高阳极进气湿度可以加快水从阳极到阴极的净迁移,在较高电流密度下阴极进气湿度过低对电池性能影响较大。     

Recent development of organic electron transport materials

This article reviews the recent development of organic electron transport materials applied in the fields of organic photoconductors, light-emitting diodes, field-effect transistors and solar cells. Several technologies for charge carrier mobility measurement are summarized and compared, and a series of basic principles for designing high-performance organic electron transport materials are suggested as well.     

Coulomb-blockade transport in single-crystal organic thin-film transistors

Coulomb-blockade transport--whereby the Coulomb interaction between electrons can prohibit their transport around a circuit--occurs in systems in which both the tunnel resistance, Rb between neighbouring sites is large (>h/e2) and the charging energy, E(C) (E(C) = e2/2C, where C is the capacitance of the site), of an excess electron on a site is large compared to kT. (Here e is the charge of an electron, k is Boltzmann's constant, and h is Planck's constant.) The nature of the individual sites--metallic, superconducting, semiconducting or quantum dot--is to first order irrelevant for this phenomenon to be observed. Coulomb blockade has also been observed in two-dimensional arrays of normal-metal tunnel junctions, but the relatively large capacitances of these micrometre-sized metal islands results in a small charging energy, and so the effect can be seen only at extremely low temperatures. Here we demonstrate that organic thin-film transistors based on highly ordered molecular materials can, to first order, also be considered as an array of sites separated by tunnel resistances. And as a result of the sub-nanometre sizes of the sites (the individual molecules), and hence their small capacitances, the charging energy dominates at room temperature. Conductivity measurements as a function of both gate bias and temperature reveal the presence of thermally activated transport, consistent with the conventional model of Coulomb blockade.     

双阴离子吗啉型离子液体结构性能的量子化学研究

用密度泛函理论在B3LYP/6-31G*的计算水平上研究了同种阳离子不同阴离子或同种阴离子不同阳离子的吗啉型离子液体对其优化结构和结合能的影响.结果表明:同一种离子液体形成两种构型(mon构型和orth构型),阴阳离子间主要通过6个氢键相互作用,除了乙醇N-甲基吗啉二氯中最强的氢键是Cl-与O原子上的H原子形成的氢键外,其他两种阳离子,卤素离子与吗啉环上3位和4位碳上的氢质子之间的氢键作用最强;所有的反应均是放热反应,阴阳离子之间的相互作用能非常大,说明阴阳离子之间均形成较强的相互作用,不同的阴离子和阳离子对其结合能都有影响.     

液相有机氢载体的催化研究与应用

氢能清洁高效、能量密度高,是理想的能源载体,也是公认的未来能源发展方向之一。氢气的存储是氢能利用的关键环节,目前仍没有完美适配所有场景的储氢材料,储氢技术的选择势必要以使用场景为导向。液相有机氢载体（liquid organic hydrogen carriers,LOHCs）作为一种液相储氢材料,在运输方面具有独特的应用优势。本文介绍了常见的液相有机储氢材料,重点探讨了适用于运输工具（车、船、航空器等）的LOHCs,综述其加氢/脱氢的催化研究进展、应用技术难点,并展望了其应用前景。     

Active fluidization of polymer networks through molecular motors

Entangled polymer solutions and melts exhibit elastic, solid-like resistance to quick deformations and a viscous, fluid-like response to slow deformations. This viscoelastic behaviour reflects the dynamics of individual polymer chains driven by brownian motion: since individual chains can only move in a snake-like fashion through the mesh of surrounding polymer molecules, their diffusive transport, described by reptation, is so slow that the relaxation of suddenly imposed stress is delayed. Entangled polymer solutions and melts therefore elastically resist deforming motions that occur faster than the stress relaxation time. Here we show that the protein myosin II permits active control over the viscoelastic behaviour of actin filament solutions. We find that when each actin filament in a polymerized actin solution interacts with at least one myosin minifilament, the stress relaxation time of the polymer solution is significantly shortened. We attribute this effect to myosin's action as a 'molecular motor', which allows it to interact with randomly oriented actin filaments and push them through the solution, thus enhancing longitudinal filament motion. By superseding reptation with sliding motion, the molecular motors thus overcome a fundamental principle of complex fluids: that only depolymerization makes an entangled, isotropic polymer solution fluid for quick deformations.     

有机溶剂透过纳滤膜的通量模型研究

在经典通量模型H-P方程的基础上，建立了有机溶剂通过纳滤膜通量(J)的数学模型。通过实验考察了溶剂黏度(μ)、摩尔体积(V_m)和溶解度参数(δ²)对溶剂J的影响，验证了所建模型的准确性和适用范围。结果表明，V_m和δ²是影响有机溶剂纳滤膜J的重要参数。对纯溶剂，该模型能较好的解释其传递规律，与实验有较好的一致性；对混合溶剂，该模型与实验数据的吻合较差，说明混合溶剂J的影响因素较复杂。