TiO2修饰La0.6Sr0.4Co0.2Fe0.8O3-δ用于中温固体氧化物燃料电池的阴极

纳米TiO2修饰的La0.6Sr0.4Co0.2Fe0.8O3-δ(LSCF)阴极被直接应用于YSZ电解质电池上. TiO2可阻止LSCF和YSZ间的化学反应,抑制SrZrO3的形成. LSCF-0.25 wt% TiO2阴极电池在0.7 V和600°C下的电流密度是LSCF阴极电池的1.6倍.电化学阻抗谱结果表明, TiO2修饰显著加快了氧离子注入电解质的过程,这可能与TiO2抑制了阴极/电解质界面处高电阻SrZrO3层的形成有关.本文为在ZrO2基电解质上使用高性能的(La,Sr)(Co,Fe)O3阴极材料提供了一种简单有效的方法.     

多层非线性抗震钢结构的损失估计与优化设计

本文通过结构的动力可靠性分析和损失估计建立了以动力可靠性为约束的非线性抗震结构双目标(造价与损失期望)优化设计模型,提出了具体实现这种优化设计思想的实际可行的方法。文中将地震地面运动模拟为平稳过滤有色噪声,建立了以破坏指数刻划的结构体系的模糊震害等级,提出了结构模糊动力可靠性分析和损失估计的具体方法,从而使优化设计模型中各有关量的分析和计算得以具体地实现。     

Polymers in gene therapy technology

There are several barriers to gene delivery. One of the biggest challenges is the design of appropriate vectors. Currently, nonviral vectors have received significant attention because of low toxicity, potential for tissue specificity, stability during storage, lack of immunogenicity, and relatively low production cost. Despite the high efficiency of viral vectors, they show limited clinical applications because of potentially fatal adverse effects and because of the likelihood of the immune response shutting down the transgene expression system. Nonviral technologies comprise plasmid‐based expression systems harboring a gene that encodes a therapeutic protein along with a synthetic gene delivery system. This review provides a broad perspective on recent improvements in the development of four kinds of nonviral vectors that are based on polymers, peptides, lipids, and DNA and discusses the cytotoxicity associated with gene therapy. Copyright © 2014 John Wiley & Sons, Ltd.     

Functionalization of a Rigid Divalent Ligand for LecA,a Bacterial Adhesion Lectin

The bacterial adhesion lectin LecA is an attractive target for interference with the infectivity of its producer P. aeruginosa. Divalent ligands with two terminal galactoside moieties connected by an alternating glucose-triazole spacer were previously shown to be very potent inhibitors. In this study, we chose to prepare a series of derivatives with various new substituents in the spacer in hopes of further enhancing the LecA inhibitory potency of the molecules. Based on the binding mode, modifications were made to the spacer to enable additional spacer–protein interactions. The introduction of positively charged, negatively charged, and also lipophilic functional groups was successful. The compounds were good LecA ligands, but no improved binding was seen, even though altered thermodynamic parameters were observed by isothermal titration calorimetry (ITC).     

Synthesis and crystal structures of four three-dimensional hybrid materials based on polyoxovanadate bridging macrocyclic copper/nickel complexes

Transition Metal Chemistry - In this research, four hybrid materials, namely [Ni(MC)]3[VO3]6·12.25H2O (1), [Cu(MC)]3[VO3]6 (2), [Ni(PC)]3[VO3]6·2H2O (3), and [Cu(PC)]3[VO3]6·2H2O (4)...     

基于N-掺杂碳包覆Fe3N复合材料的高效异相电芬顿降解有机物

水污染导致的缺水危机、水质恶化和生态环境破坏等问题,严重影响人的健康及社会的和谐可持续发展.异相电芬顿技术因催化剂可循环利用、宽pH适用范围等优点而广受关注.常见的催化剂以铁、铁氧化物等铁基材料为主,存在金属颗粒分布不均匀、铁元素易溶出、铁循环易受阻和H₂O₂选择性和转化效率低等问题,严重制约该技术的发展.尽管可以通过变价金属和非金属掺杂提高H₂O₂转化效率和选择性等,但铁基催化剂的异相电芬顿性能仍有待提升.因此,亟待开发一种具有合金性质且宽pH响应的高H₂O₂选择性及转化效率、高稳定性的铁基催化剂.本文利用具有高分散的金属位点和丰富碳源的铁基金属有机骨架材料,采用同步高温煅烧和氨气刻蚀等手段,制备N-掺杂碳包覆Fe₃N复合材料(Fe₃N@NG/NC),并探究了该材料在异相电芬顿降解有机污染物体系中的应用前景.XRD,SEM和TEM测试结果表明,Fe₃N@NG/NC催化剂是由N-掺杂的石墨化碳包覆的Fe₃N纳米颗粒(大小约为70 nm)均匀分散在N-掺杂碳骨架材料中组成的,这一特殊结构有利于电荷的快速传输,有助于电催化氧还原产H₂O₂及其转化至·OH反应的发生.电化学测试结果表明,该催化剂具有良好的两电子氧还原性能,在电压范围为–0.3~0.1 V内的H₂O₂选择性为82.2%~74.5%,电子转移数为2.35~2.50.电子顺磁共振光谱结果表明,该催化剂在异相电芬顿体系中主要的活性物质为·OH.XPS结果表明,该催化剂中高含量的石墨N和吡啶N、Fe(Ⅱ)有利于电催化合成H₂O₂和活化H₂O₂至·OH,使其具有高效的异相电芬顿性能.异相电芬顿降解评估结果表明,该催化剂在pH 5.0体系中120 min内能高效去除罗丹明(RhB)、邻苯二甲酸二甲酯、亚甲基蓝和橙黄Ⅱ等多种有机污染物(有机物去除率为97%~100%,TOC去除率为49%~65%),不同RhB降解体对其去除率贡献程度依次为异相电芬顿>电催化>电生成H₂O₂氧化>O2氧化>吸附;能实现宽pH范围内RhB的高效去除(在pH为3.0,5.0,7.0和9.0条件下,在60 min内的RhB去除率分别为100%,96%,92%和81%);在宽pH范围内呈现出高稳定性,铁溶出量为0~0.03 mg/L;经过6次循环使用后,仍具有高的异相电芬顿性能(去除率达90%以上).综上所述,Fe₃N@NG/NC复合材料能作为良好的异相电芬顿催化剂,应用于污水处理领域.     

Investigation of yellow luminescence intensity of N-polar unintentionally doped GaN

This paper reports that the yellow luminescence intensity of N-polar GaN Epi-layers is much lower than that of Ga-polar ones due to the inverse polarity,and reduces drastically in the N-polar unintentionally-doped GaN after etching in KOH solution.The ratio of yellow luminescence intensity to band-edge emission intensity decreases sharply with the etching time.The full width at half maximum of x-ray diffraction of(10-12) plane falls sharply after etching,and the surface morphology characterized by scanning electron microscope shows a rough surface that changes with the etching time.The mechanism for the generation of the yellow luminescence are explained in details.     

硅基二氧化硅光波导器件偏振特性的理论分析

从理论上分析了硅基二氧化硅光波导器件的芯区尺寸、相对折射率差、内应力和弯曲径对器件偏振特性的影响,得出结论：小折射率差的正方形波导的双折射系数小;内应力对双折射的影响比几何参数大;弯曲半径较小时,双折射系数较大,弯曲损耗也较大。     

应用水解还原铁(Ⅲ)-邻二氮菲光度法测定丙酮肟

丙酮肟在酸性条件下经加热水解生成具有还原性的羟胺,并将Fe(Ⅲ)定量还原为Fe(Ⅱ),应用Fe(Ⅱ)-邻二氮菲光度法简接测定丙酮肟。选择了水解最佳条件(加热温度、时间、介质酸度、显色剂的加入顺序等),结果表明,测定线性范围为0～1.2mg/L,相关系数r=0.9998,最低检测浓度为0.046 mg/L,RSD<3.3％(n=5)。应用该法测定火力发电厂锅炉运行水中丙酮肟的含量,方法简便,灵敏度高。     

金属氧化物对铁系催化剂在CO变换反应中的稳定性和活性的影响(英文)

铁系催化剂一直是合成氨及制氢工业中一氧化碳变换反应最常用的催化剂。运用X射线衍射（XRD）、程序升温还原（TPR）及活性评价技术研究了添加金属氧化物对铁系催化剂的晶相结构、催化剂的稳定性和催化活性的影响。结果表明,不同的金属氧化物对催化剂结构的稳定作用和活性影响不同,其中CeO2和Bi2O3都能增强铁系催化剂的稳定性,提高催化剂的活性。