Effects of ultrasonic field on structure evolution of Ni film electrodeposited by bubble template method for hydrogen evolution electrocatalysis

Journal of Solid State Electrochemistry - Self-supporting porous Ni film with uniform honeycomb-like micropores and a thickness of up to 66 μm is electrodeposited by dynamic hydrogen...     

呼出气体酒精含量探测器检定的注意事项

介绍呼出气体酒精含量探测器的工作原理和国家标准对使用探测器的要求,为确保探测器有效准确的量值溯源,采用呼出气体酒精含量探测器自动检测系统进行检定。该系统能够解决标准气体不易保存和定值容易发生改变的难题,同时控制吹气压力,保证探测器采样的一致性,并列举了检定操作时应注意的问题和细节。     

复合酶酶解假酸浆黄酮苷抗氧化性研究

本文研究了复合酶酶解前后假酸浆提取物的抗氧化活性能力,并采用薄层色谱法(TLC)对酶解产物中总黄酮进行了分离,利用高效液相色谱-质谱联用技术对其鉴定分析。通过对DPPH自由基、羟自由基及超氧阴离子自由基清除能力实验,酶解液抗氧化性能显著高于假酸浆提取液;酶解液的薄层及HPLC-MS法初步鉴定出假酸浆中含有桑色素、二氢槲皮素和儿茶素三种黄酮。     

Uniform hierarchical silica film with perpendicular macroporous channels and accessible ordered mesopores for biomolecule separation

Herein, we demonstrate that silica films with perpendicular macroporous channels and accessible ordered mesopores can be conveniently prepared. The hierarchical macroporous–mesoporous silica films are synthesized by using zinc oxide nanorod array as macroporous template and CTAB surfactant as mesoporous template. In basic surfactant-containing solution, ordered mesoporous silica shells homogeneously grow on the zinc oxide nanorod array. The growth of the mesostructures do not require any chemical modification for the zinc oxide nanorod, which opens a new way for preparing hierarchical silica films with perpendicular mesochannels. The prepared hierarchical macroporous–mesoporous silica films possess a uniform thickness of 2 mm, large perpendicular macropores with a length of 1.8 mm and a width of 80 nm, and accessible ordered mesopores. Separation experiment demonstrates that this macroporous–mesoporous film can effectively separate biomolecules with different sizes.     

New advances in microfluidic flow cytometry

In recent years, researchers are paying the increasing attention to the development of portable microfluidic diagnostic devices including microfluidic flow cytometry for the point‐of‐care testing. Microfluidic flow cytometry, where microfluidics and flow cytometry work together to realize novel functionalities on the microchip, provides a powerful tool for measuring the multiple characteristics of biological samples. The development of a portable, low‐cost, and compact flow cytometer can benefit the health care in underserved areas such as Africa or Asia. In this article, we review recent advancements of microfluidics including sample pumping, focusing and sorting, novel detection approaches, and data analysis in the field of flow cytometry. The challenge of microfluidic flow cytometry is also examined briefly.     

Structural Engineering of Luminogens with High Emission Efficiency Both in Solution and in the Solid State

Developing molecules with high emission efficiency both in solution and the solid state is still a great challenge, since most organic luminogens are either aggregation‐caused quenching or aggregation‐induced emission molecules. This dilemma was overcome by integrating planar and distorted structures with long alkyl side chains to achieve DAπAD type emitters. A linear diphenyl–diacetylene core and the charge transfer effect ensure considerable planarity of these molecules in the excited state, allowing strong emission in dilute solution (quantum yield up to 98.2 %). On the other hand, intermolecular interactions of two distorted cyanostilbene units restrict molecular vibration and rotation, and long alkyl chains reduce the quenching effect of the π–π stacking to the excimer, eventually leading to strong emission in the solid state (quantum yield up to 60.7 %).     

真空蒸馏预富集-电感耦合等离子体发射光谱法测定铂

建立了真空蒸馏预富集-电感耦合等离子体发射光谱法测定铅试样中微量铂的方法.在真空条件下,利用Pb和Pt在较高温度下蒸汽压的差别进行分离,富集后的铂溶解制成溶液后进行电感耦合等离子体发射光谱检测,实现了真空密闭回收铅.针对试样的特点,对真空蒸馏方法理论上的可行性进行研究.结果表明:在蒸馏温度为1250 K,真空度为30 Pa,蒸馏时间为3 h条件下,铂的富集分离效果最好,可富集至99.01%以上.线性范围为0.023～20 mg/L,检出限(3σ)为0.0069 mg/L,对样品测定的相对标准偏差为1.7%(n=6).用本方法对样品中加入的铂标准溶液进行了测定,回收率为99.8%～103.0%.本方法简便快速、无污染,已应用于废电路板贵金属冶余物料中铂的测定.     

水分子通道蛋白的结构与功能

水分子穿越双磷脂生物膜的输运机理是生理学和细胞生物学中一个长期未能解决的重要问题.AQP1水通道蛋白的发现和鉴定使得人们确认出一个新的蛋白质家族--水通道蛋白家族.正是这一蛋白家族的存在,使得水分子可以进行快速的跨膜传输.由晶体学方法解出的哺乳动物AQP1水通道蛋白的原子结构,最终揭示了水通道蛋白只允许水分子快速传输而阻挡其他的小分子和离子(包括质子H+)的筛选输运机理.本文概述了水通道蛋白的发现和其对水分子的筛选传输机理.     

Aggregation of sodium 1-(n-alkyl)naphthalene-4-sulfonates in aqueous solution: micellization and microenvironment characteristics

In aqueous solution, the micellization and microenvironment characteristics of the micelle assemblies of three anionic surfactants, sodium 1-(n-alkyl)naphthalene-4-sulfonates (SANS), have been investigated by steady-state fluorescence and time-resolved fluorescence decay techniques using pyrene, Ru(bpy)3(2+), and 1,6-diphenyl-1,3,5-hexatriene as fluorescence probes. The critical micelle concentrations (cmc's), effective carbon atom numbers (neff's), hydrophilic-lipophilic balances (HLBs), mean micelle aggregation numbers, micropolarities, and microviscosities of these surfactant micelles have been determined. The logarithmic cmc of the alkylnaphthalene sulfonates decreases linearly with an increase in the neff. The logarithmic aggregation number of the alkylnaphthalene sulfonates increases linearly with an increase in the neff. However, in contrast to the alkylsufonates and the alkylbenzene sulfonates, the aggregation for these alkylnaphthalene sulfonate molecules is less sensitive to the increase in the neff. The micropolarity of these alkylnaphthalene sulfonate micelles is less sensitive to the increase in the alkyl chain length and is lower than that of sodium dodecyl sulfate (SDS). The microviscosity of these alkylnaphthalene sulfonate micelles increases with an increase in the alkyl chain length and is lower than those of nonionic surfactants and zwitterionic surfactants. These results suggest that naphthyl rings have a notable effect on the micellization of SANS.