石墨毡载纳米δ-MnO2高性能除铵净水材料研究

首先制备了α-MnO₂纳米花簇、β-MnO₂纳米针和δ-MnO₂微米颗粒三种不同晶型的MnO₂粉末材料，对其结构、形貌及吸附除铵能力进行了表征和测试.结果表明，层间距（7.2Å）大于NH₄⁺直径（2.96Å）和水合NH₄⁺直径（6.62Å）的δ-MnO₂相比其他两种晶型的MnO₂有更高的NH₄⁺吸附量；接着研究采用KMnO₄原位氧化还原法在石墨毡（GF）上直接生长超薄δ-MnO₂纳米片（MnO₂NPs）阵列构筑了石墨毡载纳米MnO₂（MnO₂NPs/GF）多级结构材料，制备简单，无须成型造粒就可直接用作除铵净水材料，研究结果表明，MnO₂NPs/GF不仅具有较高的吸附量（15 mg·g^－1）与良好的选择性，同时还展现了优异的快速吸附和稳定的循环使用性能.MnO₂NPs/GF对水中NH₄⁺的吸附符合准二级动力学模型，其吸附等温线符合Langmuir吸附等温式，是吸附-离子交换法除铵的理想材料.     

Selective N-Alkylation of 2-Amino-4H-chromene-3-carbonitrile Derivatives with Alcohols Catalyzed by AlCl3 Under the Assistance of CH3COOH

A highly efficient and selective N-alkylation reaction of 2-amino-4H-chromene-3-carbonitrile derivatives using various alcohols as alkylation agent were developed in the presence of AlCl₃ as a catalyst as well as CH₃COOH as an additive, in which the cyano group kept inert and the amino group was alkylated in high yields. All the target products were characterized and determined by infrared(IR), ¹H NMR, ¹³C NMR, and HRMS. And the X-ray structure of product 3ab was obtained. A bimolecular reaction mechanism catalyzed by AlCl₃ was proposed under the assistance of CH₃COOH.     

Electrochemiluminescence sensor based on methionine-modified gold nanoclusters for highly sensitive determination of dopamine released by cells

The electrogenerated chemiluminescence (ECL) of methionine stabilized gold nanoclusters (Met-AuNCs) is presented. The Met-AuNCs were used to modify a glassy carbon electrode (Met-AuNC/GCE) which is shown to exhibit a stable and strong cathodic ECL signal (at ?1.86 V) when using potassium peroxodisulfate (K₂S₂O₈) as the coreactant in aqueous solution of pH 7.4. Compared to a GCE modified with BSA-AuNCs, the ECL intensity of Met-AuNCs is 5-fold enhanced. The possible ECL reaction mechanism of the ECL system was studied, and a method for the determination of dopamine (DA) was worked out. The modified GCE has a linear response in the 0.1 to 4 μM DA concentration range, with a detection limit of 32 nM (at an S/N ratio of 3). The method was applied to the determination of DA released by PC12 cells. In our perception, the Met-AuNC/GCE provides a viable new tool in ECL based bioanalysis that also paves new routes to the design and application of new sensors.

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Graphical abstract The electrochemiluminescence (ECL) sensor based on methionine stabilized gold nanocluster modified glassy carbon electrode (Met-AuNC/GCE) using potassium peroxodisulfate (K₂S₂O₈) as the coreactant in aqueous solution was fabricated for the highly sensitive detection of dopamine (DA) released by cells.

     

神光Ⅱ高功率激光系统中鬼像的计算与分析

对神光Ⅱ高功率像传递激光传输系统中可能产生的鬼像进行了计算与分析，对系统中可能被鬼像损伤位置上的光学件作了重整安排。     

硫肽类抗生素化学半合成修饰研究进展

硫肽类抗生素是一类由微生物次级代谢产生、富含硫元素并且氨基酸残基被高度修饰的核糖体肽类天然产物. 硫肽类抗生素具有包括抗感染、抗肿瘤和免疫抑制在内的一系列十分重要的生物活性, 并且其以核糖体为靶点的作用机制与目前临床上普遍使用的抗生素均不同, 这使得硫肽类抗生素发展潜力巨大, 但是其水溶性差、生物利用度低等问题限制了它们在临床上的应用. 为了提高硫肽类抗生素的理化性质, 研究者尝试用化学半合成、组合生物合成以及前体导向突变生物合成等方法对硫肽类抗生素的结构进行修饰. 硫肽类抗生素本身具有的复杂结构为其化学半合成修饰提供了众多的可修饰位点. 近年来, 对于硫肽类抗生素的化学半合成修饰研究发展迅速. 综述了近十年通过化学半合成修饰方法获得的硫肽类抗生素类似物的研究进展.