二维DNA晶体的程序化设计与自组装的研究进展

按照Watson-Crick的碱基配对原则，在理论上能够人工设计与合成DNA碱基序列并自组装成任何一维和二维结构的DNA晶体。DNA分子这种底端向上(bottom-up)的自组装模式为我们提供了一种精确合成纳米材料的方法。本文将从程序化设计、合成刚性的DNA分子瓦(DNA tile)、分子瓦自组装成二维DNA晶体以及二维DNA晶体作为模板在纳米技术中的应用等方面展开，简述这一新奇的并且有着潜在应用前景的研究领域的最新进展。     

一种新的磷酸根离子敏感电极研究

一种新的磷酸根离子敏感电极研究肖丹，俞汝勤，李军，袁孔铨（湖南大学化学化工系，长沙，４１００８２）关键词磷酸根，离子选择电极，磷酸二氢根磷酸根离子浓度的测定在化学化工、环境保护、生命科学和临床医学等领域有着重要的意义。对磷酸根离子敏感电极的研究和探索...     

用石英晶体微天平研究表面活性剂在银固态表面上的动态吸附

吸附是表面活性剂的一个重要特征.迄今用于原位监测表面活性剂在固体表面上吸附重量变化的方法尚不多见.近年来压电石英晶体作为一种高灵敏的质量传感器(石英晶体微天平)已被用于大气和溶液中多种微量成分的监测.用石英晶体微天平研究I~-、Br~-和表面活性剂在金电极上的吸附行为亦有报道.本文研究了十六烷基三甲基溴化铵(CTAB)、十二烷基磺酸钠(SDSO)、十二烷基硫酸钠(SDS)在银固态表面上的吸附平衡动力学特性及其吸附机制.     

非晶SiO2纳米灯笼的制备和表征

在1000 ℃用活性炭把二氧化锡粉末还原成单质锡, 锡作为催化剂, 硅片作为硅源同时作为收集衬底, 在硅片上制备出了非晶SiO2纳米灯笼. 灯笼的一端连在硅片上, 另一端为一个锡球, 中间是一些圆弧状的SiO2纳米线把两端相连. 纳米灯笼具有良好的对称性. 利用扫描电子显微镜(SEM)、高分辨透射电子显微镜(HRTEM)、选区电子衍射(SAED) 和HRTEM自带的能谱分析仪(EDS)对样品的表面形貌、微观结构和成分进行了分析研究. 结果表明, 灯笼中SiO2纳米线为非晶态, 结点是晶态锡, 结点表面覆盖一层非晶态的硅的氧化物. 结合实验条件对纳米灯笼的生长机理进行了讨论, 提出了纳米灯笼生长的一个模型.     

Nitration Reaction Catalyzed by Horseradish Peroxidase in the Presence of H2O2 and NaNO2

The enzymatic nitration of phenol and m-cresol catalyzed by horseradish peroxidase was studied in the presence of H2O2 and NaNO2. The results showed that the nitration products of phenol were 2-nitro and 4-nitrophenols. There was also a small amount of by-products of hydroquinone and catechol. The influences of various reaction parameters, including pH, organic solvent type, and concentrations of NaNO2 and H2O2, on the nitration products were investigated. The yields of 4-nitrophenol and 2-nitrophenol were 14% and 12%, respectively. The nitration products of m-cresol were 4-nitro-m-cresol and 6-nitro-m-cresol, and the yields of 4-nitro-m-cresol and 6-nitro-m-cresol were 19% and 30%, respectively.     

Photovoltaic Characteristics of a Naphthylamine Derivative

Organic photovoltaic （OPV） cells were fabricated via vacuum vapor deposition with {4-[2-（3-di-cyanomethylidene-5,5-dimethylcyclohexenyl）vinyl]phenyl}di（1-naphthyl）amine （DNP-2CN） as the electron donor, and fullerene （C60） as the electron acceptor. A thin film （10 nm） of tris（8-quinolinolato）aluminum （Alq3） was adopted as the buffer layer. A device based on this DNP-2CN exhibited an open circuit voltage （Voc） of 370 mV, a short-circuit current density （Jsc） of 0.61 mAocm 2, and a white-light power conversion efficiency （ η） of 0.09% （AM1.5, 75 mW.cm^- 2）.     

SinH/SinH-(n=3～8)的结构和电子亲合能的研究

选用四种不同的密度泛函理论方法(B3LYP，B3P86，BLYP，BP86)，在全电子的双ξ加极化加弥散函数基组(DZP )下，对SinH／SinH^-(n=3～8)体系进行研究，获得它们的基态结构和电子亲合能。预测Si3H／Si3H^-,Si4H／Si4H^-,Si5H／Si5H^-,Si6H／Si6H^-，Si7H／Si7H^-和Si8H／Si8H^-的基态结构分别为C2v(^2B2)／C2v(1^A1)氢桥结构，Cs(^2A’)／C(^1A’)，C2v(^2B2)／C2v(^1A1)，C2v(^2B2或^2B1)／C4v(^1A1)，C5v(^2A1)／C5v(^1A1)和C5(^2A‘‘)／C3v(^1A1)。在电子亲合能方面，B3LYP方法预测的电子亲合能是最可靠的，预测Si3H，Si4H，Si5H，Si6H，Si7H和Si8H的电子亲合能分别为2．56，2．59，2．84，2．86，3．19和3．14eV。     

赖氨酸-Ag反应机理的研究

The interaction of silver(Ⅰ) ion with lysine has been investigated by UV-Vis, fluorescent spectra and electrophoresis method. The effect of pH medium and multicomponent concentration on interaction of lysine-silver has also been studied. Lysine-silver system showed maximum absorbance at 239 nm and 448 nm. Lysine showed fluorescence. The fluorescence excitation wavelength was about 356.6 nm (fluorescence emission wavelength was about 438.6 nm). When the reaction of silver(Ⅰ) ion with lysine happened, fluorescence was quenching. Lysine-silver system carried negative charge, and the electrokinetic potential of double electrode layer was -2.35×10^-4 V.     

The Crystalline Changes of Starch from Rhizoma Dioscorea by Acid Hydrolysis

Dioscoreae (Chinese name Shanyao), the rhizome of various species of genus Dioscorea opposita Thunb.(Dioscoreaceae), has been used as an important invigorant in traditional Chinese medicine (TCM) for many years1. Starch, the most abundant carbohydrate in …     

TiO2/P(VdF-HFP)杂化纤维微孔膜的制备及其电化学性能

用电纺法制备了TiO₂/P(VdF-HFP)(聚偏氟乙烯-六氟丙烯共聚物)杂化纤维微孔膜, 用SEM观察了杂化纤维微孔膜的形貌, 并测算了这类由超细纤维相互搭接而形成的微孔膜的孔隙率. 这种微孔膜吸附LiPF₆/EC-DMC-EMC(碳酸乙烯酯-二甲基碳酸酯-碳酸甲乙酯)电解质溶液后得到凝胶聚合物电解质膜. 用电化学方法测试了聚合物电解质膜的离子电导率、锂离子迁移数等参数, 并研究了TiO₂纳米晶的掺入对聚合物电解质电化学性能的影响. 结果表明, TiO₂的掺入降低了P(VdF-HFP)聚合物基体的结晶度, 改善了凝胶聚合物电解质的低温电化学性能.