静电纺丝技术与硫化技术相结合制备La2Fe2S5亚微米棒

采用静电纺丝技术制备了PVP/[La(NO3)3+Fe(NO3)3]复合纳米纤维,在700℃下焙烧得到LaFeO3纳米纤维,再以CS2作为硫源进行硫化,成功制备了La2Fe2S5亚微米棒。利用XRD,SEM,EDS,宽频介电松弛谱仪等现代分析手段对样品进行了表征。XRD分析表明:将LaFeO3纳米纤维在CS2气氛中于900℃焙烧4 h得到纯相的La2Fe2S5亚微米棒,属于正交晶系,空间群为A21am。SEM分析表明:La2Fe2S5呈亚微米棒结构,直径和长度分别为851±122 nm和3.25±0.99μm。电分析表明:La2Fe2S5亚微米棒是较好的半导体材料。     

软X射线光谱的第一性原理模拟(英文)

软X射线光谱是通过核激发或去激发以探测分子、表面及各种化合物的电子结构和化学结构的有效的测量技术。本文对基于密度泛函理论描述X射线吸收、发射的各种不同过程的计算方法进行了综述。重点讨论了各种方法的基本原理、实际操作和具体应用。提供了K边X射线光电子能谱、吸收和发射光谱详细的模拟细节以及一些代表性体系的算例(包括分子、富勒烯、碳纳米管、单层石墨和DNA链)。     

Layer-by-layer assembly of microcapsules and their biomedical applications

Nanoengineered multifunctional capsules with tailored structures and properties are of particular interest due to their multifunctions and potential applications as new colloidal structures in diverse fields. Among the available fabrication methods, the layer-by-layer (LbL) assembly of multilayer films onto colloidal particles followed by selective template removal has attracted extensive attention due to its advantages of precise control over the size, shape, composition, wall thickness and functions of the obtained capsules. The past decade has witnessed a rapid increase of research concerning the new fabrication strategies, functionalization and applications of this kind of capsules, particularly in the biomedical fields such as drug delivery, biosensors and bioreactors. In this critical review, the very recent progress of the multilayer capsules is summarized. First, the advances in assembly of capsules by the LbL technique are introduced with focus on tailoring the properties of hydrogen-bonded multilayer capsules by cross-linking, and fabrication of capsules based on covalent bonding and bio-specific interactions. Then the fabrication strategies which can speed up capsule fabrication are reviewed. In the following sections, the multi-compartmental capsules and the capsules that can transform their shape under stimulus are presented. Finally, the biomedical applications of multilayer capsules with particular emphasis on drug carriers, biosensors and bioreactors are described (306 references).     

Application studies of activated carbon derived from rice husks produced by chemical-thermal process--a review

The production of functional activated carbon materials starting from cheap natural precursors using environmentally friendly processes is a highly attractive subject in material chemistry today. Recently, much attention has been focused on the use of plant biomass to produce functional carbonaceous materials, encompassing economic, environmental and social issues. Besides the classical route to produce activated carbons from fossil materials, rice husk shows clear advantages in that it can generate a variety of cheap and sustainable carbonaceous materials with attractive nanostructure and functional patterns for a wide range of applications. From a comprehensive literature review, it was found that porous carbon that derived from rice husks, in addition to having wide availability, has fast kinetics and appreciable adsorption capacities too. Porous carbon materials also play a significant role in new applications such as catalytic supports, battery electrodes, capacitors, and gas storage. In this review, an extensive list of rice husks literature has been compiled. Conclusions have been drawn from the literature reviewed, and suggestions for future research are proposed.     

One-pot synthesis of stable NIR tetracene diimides via double cross-coupling

Tetracene tetracarboxylic diimides have been synthesized based on direct double ring extension of electron-deficient naphthalene diimides involving metallacyclopentadienes. Atomic structure and electronic transitions responsible for their NIR absorption spectra are investigated with quantum-chemical calculations. In light of their unique structure and admirable photophysical and electronic properties, this new molecular skeleton is promising candidate for n-type semiconductors.     

Fast and sensitive high performance liquid chromatography analysis of cosmetic creams for hydroquinone, phenol and six preservatives

A fast and sensitive HPLC method for analysis of cosmetic creams for hydroquinone, phenol and six preservatives has been developed. The influence of sample preparation conditions and the composition of the mobile phase and elution mode were investigated to optimize the separation of the eight studied components. Final conditions were 60% methanol and 40% water (v/v) extraction of the cosmetic creams. A C18 column (100 mm × 2.1 mm) was used as the separation column and the mobile phase consisted of methanol and 0.05 mol/L ammonium formate in water (pH=3.0) with gradient elution. The results showed that complete separation of the eight studied components was achieved within 10 min, the linear ranges were 1.0-200 μg/mL for phenol, 0.1-150 μg/mL for sorbic acid, 2.0-200 μg/mL for benzoic acid, 0.5-200 μg/mL for hydroquinone, methyl paraben, ethyl paraben and propyl paraben, butyl paraben, and good linear correlation coefficient (≥0.9997) were obtained, the detection limit was in the range of 0.05-1.0 μg/mL, the average recovery was between 86.5% and 116.3%, and the relative standard deviation (RSD) was less than 5.0% (n=6). The method is easy, fast and sensitive, it can be employed to analyze component residues in cosmetic creams especially in a quality control setting.     

中国化学物相分析研究的新成就(下)

分两部分介绍了我国化学物相分析近十余年来研究的新成就。第二部分（下）则对物料物质组成的相态与元素(Fe,I,Mn,Mo,Na,P,Re,S,Sb,Se,Si,Sn,Sr,Ti,U和V等)价态分析、赋存状态分析以及非金属矿物相分析等的研究现状,分别予以简要评述。同时对其存在的问题和进一步研究的方向也进行了讨论。引用文献114篇。     

固相萃取-高效液相色谱/串联质谱法测定食醋中的3种甜味剂

建立了食醋中3种甜味剂的固相萃取-高效液相色谱/串联质谱分析方法。样品经酸性水稀释,弱阴离子固相萃取柱净化,Pursuit C18色谱柱分离,10 mmol/L醋酸铵(含0.1%氨水)和乙腈为流动相梯度洗脱,电喷雾负离子模式下多反应监测(MRM)模式检测。糖精钠、安赛蜜、甜蜜素的定量限分别为10、5、5 μg/kg,回收率为72.1%～96.8%,相对标准偏差小于15%。该方法准确、灵敏度高,可用于食醋中甜味剂的定性定量检验。     

柱前衍生化-高效液相色谱法分析木糖结晶母液的单糖组成

采用1-苯基-甲基-吡唑啉酮(PMP)柱前衍生化-反相高效液相色谱(HPLC)法建立了8种常见单糖的分离模式,并用于木糖结晶母液单糖组成的定量分析.结果表明:木糖结晶母液至少由甘露糖、鼠李糖、纤维二糖、葡萄糖、半乳糖、木糖、阿拉伯糖及岩藻糖8种单糖组成,其中以葡萄糖、半乳糖、木糖和阿拉伯糖为主.以峰高定量,8种单糖的浓...     

喹唑啉类衍生物的合成及抗菌活性研究进展

喹唑啉类化合物具有广泛的生物活性,在农药和医药领域受到了人们越来越多的关注.将不同药效团引入到喹唑啉骨架中,经结构修饰后能产生一系列具有抗菌活性的喹唑啉类化合物.本工作对近年来该类化合物的研究进行了综述,并对其发展前景进行了展望.