应变速率和电位对应力腐蚀裂纹扩展的影响

以滑移-溶解-再钝化模型为基础,推导出应力腐蚀裂纹扩展速率与裂尖应变速率和电位之间的理论公式.计算表明,在裂纹扩展速率与裂尖应变速率的关系曲线中有两个特征区域.裂纹扩展速率在区域I随裂尖应变速率增加而增大,而在区域II不随裂尖应变速率的改变而变化.用慢应变速率拉伸技术（SSRT）测量了304L不锈钢的裂纹增长速率.当电位控制在区域II的阳极区时,理论计算的裂纹扩展速率与实验得到的结果比较吻合.     

双头基两亲分子研究进展

本文介绍了双头基两亲分子的结构特征与性质, 概述了由双头基两亲分子在气液界面形成的单分子膜以及在体相中形成的囊泡的特征, 并介绍了这类两亲分子在催化、生物矿化、药物缓释、膜破解以及纳米材料等方面的应用研究。对其研究前景进行了展望。     

Coaxial electrospinning core-shell fibers for self-healing scratch on coatings

Polystyrene (PS) fibers with core-shell structure were prepared by coaxial electrostatic spinning using liquid epoxy or curing agent as the core and PS solution as the shell. Scratch self-healing coatings were realized by using the healant-loaded core-shell fibers in the matrix.     

Synthesis and lysozyme adsorption of rod-like large-pore periodic mesoporous organosilica

Highly ordered rod-like large-pore periodic mesoporous organosilica (PMO) was successfully synthesized at low acid concentration with the assistance of inorganic salt using triblock copolymer P123 as a template. The roles of inorganic salt and acidity in the production of highly ordered mesostructure and the morphology control of PMOs were investigated. It was found that the inorganic salt can significantly widen the range of the synthesis parameters to produce highly ordered 2D hexagonal pore structure of p6mm symmetry. However, the uniform rod-like PMOs can only be synthesized in a narrow range of acid and salt concentrations, which were sensitive to induction time. The adsorption of lysozyme on PMO was studied at different pH values in comparison with adsorption on pure silica material under controlled morphology and pore structure. It was found that the adsorption capacity of lysozyme on the PMO was lower than that on pure SBA-15 silica material and the adsorption amounts are larger at pH 9.6 than at 7.0 for both materials. The results show that the electrostatic interaction between lysozyme and PMO/SBA-15 surface is more dominant than the hydrophobic forces and the interaction of neighboring lysozyme molecules also plays an important role.     

Acetic acid induced self-assembly of supramolecular compounds [Et4N]3[(WS4Cu2)2(mu-CN)3].2MeCN and [PPh4][WS4Cu3(mu-CN)2].MeCN from preformed clusters [A]2[WS4(CuCN)2] (A = Et4N, PPh4)

Reactions of two preformed trinuclear W/Cu/S clusters, [A](2)[WS(4)(CuCN)(2)] (1: A = Et(4)N; 2: A = PPh(4)), with different concentrations of acetic acid in MeCN generate two interesting 2D polymeric clusters [Et(4)N](3)[(WS(4)Cu(2))(2)(mu-CN)(3)].2MeCN (3), and [PPh(4)][WS(4)Cu(3)(mu-CN)(2)].MeCN (4), respectively. Compound 4 can also be readily obtained in a high yield from the reaction of 2 with equimolar [Cu(MeCN)(4)]PF(6) in MeCN. These compounds have been characterized by elemental analysis, IR spectra, thermal analysis, and single-crystal X-ray diffraction. An X-ray analysis reveals that compound 3 retains the WS(4)Cu(2) cluster core, which serves as a 3-connecting node to link equivalent nodes via single cyanide bridges, forming an anionic 2D (6,3) net. Compound 4 consists of a T-shaped WS(4)Cu(3) core, which also acts as a 3-connecting node, with links to 3 equivalent clusters either through single or double cyanide bridges, affording a different anionic 2D (6,3) network. The acetic acid induced aggregation of 3 and 4 from the two cluster precursors 1 and 2 suggests that this simple synthetic strategy is likely to be applicable to many related systems.     

Synthesis of a Photolabeling Probe for the Study of Antiviral Mechanism of Ribavirin

Ribavirin has been used in urgency to treat SARS patients recently. In order to study its antiviral mechanism by photolabeling approach, we have synthesized and characterized 5-azido-1-β-D-ribofuranosyl-1,2,4-triazole-3-carboxiamide 1 as a photolabeling probe of ribavirin. The azidotriazole nucleoside showed rapid and clean photochemical reaction, suggesting that 1 is a promising probe to study the antiviral mechanism ofribarivin by photolabeling.     

Study of hexane adsorption in nanoporous MCM-41 silica

We study here the adsorption of hexane on nanoporous MCM-41 silica at 303,313, and 323 K, for various pore diameters between 2.40 and 4.24 nm. Adsorption equilibria, measured thermogravimetrically, show that all the isotherms, that are somewhat akin to those of type V, exhibit remarkably sharp capillary adsorption phase transition steps and are reversible. The position of the phase transition step gradually shifts from low to high relative pressure with an increase in the temperature as well as the pore sizes. The isosteric heats of adsorption derived from the equilibrium information using the Clapeyron equation reveal a gradual decrease with increasing adsorbed amount because of the surface heterogeneity but approach a constant value near the phase transition. A decrease in the pore size results in an increase in the isosteric heat of adsorption because of the increased dispersion forces. A simple strategy, based on the Broekhoff and De Boer adsorption theory, successfully interprets the hexane adsorption isotherms for the different pore size MCM-41 samples. The parameters of an empirical expression, used to represent the potential of interaction between the adsorbate and adsorbent, are obtained by fitting the monolayer region prior to capillary condensation and the experimental phase transition simultaneously, for some pore sizes. Subsequently, the parameters are used to predict the adsorption isotherm on other pore size samples, which showed good agreement with experimental data.     

应用反向传播神经网络预测化合物脑血分配系数

选用27种三维结构性质描述符对脑血分配系数预测建立神经网络模型.网络模型选用典型的适合函数逼近的两层结构神经网络对脑血分配系数(lgBB,BB为脑血浓度比)进行预测,计算中采用的模型具有一个双曲正切型激活函数的隐含层和一个线性激活函数的输出层.计算表明,使用小心选择的反向传播神经网络模型对化合物脑血分配系数具有较好的预测能力.     

Ir（Ⅳ）—KBrO3—DBS—偶氮氯膦催化分光光度法测定微量铱的研究

ＫＢｒＯ３－ＤＢＳ偶氮氯膦在０．８ｍｌ．Ｌ＾－１的Ｈ２ＳＯ４介质中长时间加热亦无明显褪色现象，但在有微量铱存在时，褪色反应在３ｍｉｎ内完成，且与Ｉｒ（Ⅳ）的浓度有良好的线性关系，据此建立了微量铱的催化褪色分光光度分析法，其检出限为０．０１μｇ．１０ｍＬ＾－１铱的含量在０．０１－０．２０μｇ．１０ｍＬ＾－１范围内符合比尔定律。