Comparative XPS study between experimentally and naturally weathered pyrites

A comparative study has been carried out between experimentally and naturally weathered pyrites. Both were found to share similar species of weathering products and a similar weathering mechanism. The weathering products could be divided into sulphur-bearing or iron-bearing groups. The sulphur-bearing group was comprised of sulphate, sulphite, thiosulphate, elemental sulphur, polysulphide, and mono-sulphide. The iron-bearing group was comprised of goethite, hematite or magnetite, and iron sulphate. The weathering structural profile was also similar for both types of weathering, being composed of a surficial layer and a transitional layer. The surficial layer was made up of both the sulphur-bearing and the iron-bearing products, while the transitional layer was comprised of goethite, and hematite or magnetite. The inward migration of the weathering interface was stimulated by the diffusion of oxygen and moisture. The oxygen was considered to preferably squeeze the iron to form goethite, and the ferric ions of goethite to have acted as a bridge for electron transfer between the oxygen and bulk S₂²⁻ and Fe²⁺ of pyrite.     

基于5-(4-(2,6-二(2-吡嗪基)-4-吡啶基)苯氧基)间苯二甲酸的Mn(Ⅱ)和Ca(Ⅱ)配位聚合物的合成与晶体结构

采用对苯二甲酸为模板剂, 溶剂热法合成了2个以5-(4-(2, 6-二(2-吡嗪基)-4-吡啶基)苯氧基)间苯二甲酸(H₂L)为配体的金属-有机配位聚合物:{[MnL] ·0.5H₂O}_n (1), {[CaL(H₂O)₂]·H₂O}_n (2)。通过X-射线单晶衍射, 元素分析和红外光谱进行了结构表征。结构分析表明, 1具有(3, 3)-连接的不同手性型二维层面结构, 这些交替出现的单手性左旋型和右旋型二维平面通过配体的吡啶环与吡嗪环间π…π堆积作用构成了三维超分子结构;2是通过L^2-配体羧基桥连接相邻的Ca(Ⅱ)金属中心, 形成一条平行于b轴方向的一维链结构。研究了配位聚合物的热稳定性和2的荧光性质。     

原子转移自由基聚合法制备表面聚合物接枝四氧化三铁纳米粒子

为制备表面具有柔性高分子链的磁性微球,采用化学共沉淀法制备了具有超顺磁性的Fe3O4纳米微球,用KH550对Fe3O4纳米微球进行化学改性得到表面氨基化的Fe3O4纳米微球,与2-溴代异丁酰溴反应后制得含有引发官能团的Fe3O4纳米微球,随后将含溴的Fe3O4纳米微球与小分子单体与之通过原子转移自由基聚合(ATRP)法共聚。测试结果表明聚合物链成功地接枝到了Fe3O4纳米微球表面。     

基于适体竞争机理的溶菌酶电化学传感器

制备了基于溶菌酶适体竞争机理的信号减弱型电化学传感器,在玻碳电极上修饰羧基化的多壁碳纳米管,将带有氨基的互补适体DNA连接到多壁碳纳米管上。由于道诺霉素崁入电极上的互补DNA,而产生电化学信号,当有目标物时,适体与结合力更高的溶菌酶结合,原本的互补链解链,导致插入双链的道诺霉素脱落,电化学信号减弱。以微分脉冲伏安法测定溶菌酶,响应的范围为1～500 nmol/L,相关系数0.999,检测下限为0.5 nmol/L(S/N=3)。     

阿尔茨海默症病理机制中的金属代谢和金属药物

随着人口老龄化进程的发展,阿尔茨海默症(AD)已成为威胁中国和世界人口健康和经济的重大疾病.本文综述了近年来AD病理的分子机制的新进展,分析了其中金属代谢的意义.研究发现,在AD进程中,围绕淀粉样斑块(AP)和神经缠绕斑(NFT)的形成,多因素相互联系并发挥作用,这些主要因素包括金属内稳态、胰岛素抵抗、神经炎症、线粒体和血脑屏障改变等.与AD病理过程密切相关的主要蛋白质均参与了金属元素的生理代谢过程,而细胞金属离子的内稳态失衡加剧了AD病理的恶化.金属药物在AD诊断和治疗中可能具有以下的发展潜力:(1)AD早期诊断探针;(2)调节金属内稳态的配体和/或微量元素补充;(3)抗糖尿病金属配合物;(4)神经元和血脑屏障(BBB)保护金属药物.     

计算富勒烯结构的新方法:曲率定理*

介绍了利用曲率定理计算富勒烯结构的方法,证明了富勒烯结构中五元环数恒为12,与传统的欧拉定理法进行了对比,凸显了曲率定理法在研究多面体结构时直观形象的特点,强调了数学方法对解决化学问题和认识化学模型的重要性。     

Imaging intrinsic diffusion of bridge-bonded oxygen vacancies on TiO2(110)

We report the first measurements and calculations of the intrinsic mobility of bridge-bonded oxygen (BBO) vacancies on a rutile TiO2(110). The sequences of isothermal (340-420 K) scanning tunneling microscope images show that BBO vacancies migrate along BBO rows. The hopping rate increases exponentially with increasing temperature with an experimental activation energy of 1.15 eV. Density functional theory calculations are in very good agreement giving an energy barrier for hopping of 1.03 eV. Both theory and experiment indicate repulsive interactions between vacancies on a given BBO row.     

微纳米纤维素功能膜在能源与环境领域的应用

探寻绿色清洁的资源与材料以维持高效的社会经济增长是未来数十年人们面临的最大挑战之一. 可持续资源与绿色材料的开发是降低传统化石能源与材料比重的最有前途的方案. 纤维素作为一种可持续发展、 可生物再生、 储量丰富且低成本的天然高分子聚合物, 在众多领域中具有广泛的应用, 并且纤维素可以加工成各种构型, 包括气凝胶、 泡沫、 海绵和薄膜等. 本文介绍了不同形态的纤维素及其衍生物组装而成的功能膜在能源与环境中的应用, 综述了微纳米纤维素及其衍生物在先进功能化储能器件方面的最新进展和制备方案, 以及在用于水处理的膜分离技术中的应用, 其中重点讨论了微纳米纤维素及其衍生物功能膜在电池、 电容器及水处理等领域中的作用, 如隔膜、 柔性电极膜和分离膜等. 此外, 还对纤维素及其衍生物功能膜的未来发展进行了总结和展望.     

无溶剂法大量制备高效红光碳点及其在白光器件中的应用

以邻苯二胺、 2,5-二氨基苯磺酸和三氯化铝为原料, 通过无溶剂法大量制备了高效的红色荧光碳点 (R-CDs). 制得的碳点尺寸大约为2.4 nm, 含有13%的氮元素, 主要由高度石墨化的碳核及覆盖在其表面的大量官能团构成. 在不同的波长光激发下, 碳点在乙醇溶液中表现出不依赖于激发的红光发射, 其荧光峰位于 704 nm, 最大量子产率达到22%. 由于R-CDs具有优异的光学性质, 利用其构筑了紫外光激发的碳基白色发光二极管, 其色坐标为(0.33, 0.33), 非常接近自然光. 该研究为高效红色荧光碳点的大量制备提供了一种新路径, 同时拓宽了其在白光器件中的应用.     

Experimental and kinetic investigation of the pyrolysis,combustion, and gasification of deoiled asphalt

The pyrolysis, combustion, and gasification behaviors of deoiled asphalt were studied by a thermogravimetric analyzer and the kinetics were also analyzed using a multi-stage first-order integral model. All the experiments were conducted at non-isothermal conditions with heating rates range of 10–40 K min^?1 under N₂ (pyrolysis), air (combustion), or CO₂ (gasification) atmosphere, respectively. The results showed that, for pyrolysis, the reaction mainly occurred between 498 and 798 K and could be divided into two stages: the first was caused by the volatilization of small molecules and the second probably due to the cracking reactions. For combustion, the mass loss process could be divided into three stages: the devolatilization and oxidation first, the ignition and combustion of the volatiles second, and finally the combustion of the formed char. Under CO₂ atmosphere, the mass loss behavior was similar with that of the N₂ atmosphere at lower temperatures, but when the temperature was higher than 1,233 K, the gasification reaction obviously happened. The results of kinetic investigation showed that the multi-stage first-order integral method agreed well with the above experiments.