4f轨道的成键性质

本文介绍了目前国内外关于镧系配合物４ｆ轨道成键行为研究的现状与进展,对其理论和研究方法进行了系统的总结,归纳了４ｆ轨道的成键规律。     

Water-stable hydrazone-linked porous organic cages

Although porous organic cages (POCs), particularly imine-linked (C N) ones, have advanced significantly over the last few decades, the reversible nature of imine linkages makes them prone to hydrolysis and structural collapse, severely limiting their applications under moist or water conditions. Herein, seven water-stable hydrazone-linked (C N–N) POCs are prepared through a simple coupling of the same supramolecular tetraformylresorcin[4]arene cavitand with different dihydrazide linkers. Their structures are all determined by single-crystal X-ray crystallography, demonstrating rich structural diversity from the [2 + 4] lantern, [3 + 6] triangular prism, and unprecedented [4 + 8] square prism to the extra-large [6 + 12] octahedron. In addition, they respectively exhibit tunable window diameters and cavity volumes ranging from about 5.4 to 11.1 nm and 580 to 6800 ų. Moreover, their application in the water environment for pollutant removal was explored, indicating that they can effectively eliminate various types of contaminants from water, including radionuclide waste, toxic heavy metal ions, and organic micropollutants. This work demonstrates a convenient method for rationally constructing versatile robust POCs and presents their great application potentialities in water medium.

A convenient method for constructing water-stable hydrazone-linked porous organic cages (POCs) with tunable structures has been reported, and such POCs can be used as robust adsorbents for effective removal of various pollutants from water.     

化学探头法与荧光光谱法测定水中溶解氧量

探讨了化学探头法和荧光光谱法测定水中溶解氧的关系。分别用F检验和t检验对两组数据进行了比较,结果表明两组数据的精密度和系统误差都没有显著差异,两种方法测定溶解氧的相对标准偏差(RSD,n=9)分别为0.35%,0.33%。进而又探讨了溶解氧与NaCl含量、温度之间的关系,结果表明溶解氧含量随NaCl含量的增加、温度的升高而逐渐降低。     

大体积进样气相色谱法测定空气中的痕量苯

采用气袋采样,以大体积进样气相色谱法测定空气中的痕量苯。气袋采集的样品在8h内稳定。苯含量在0．01～0．2μL／L内与对应的色谱峰面积线性相关,线性方程为A=118．45X 0．073,相关系数为0．9994。6次测定结果的相对标准偏差为2．21％,空气中苯的检出限为0．03mg／m^3。     

每一个元素都是左零因子之环

本文引进左(右)零因子环的概念,它们是一类无单位元的环.我们称一个环为左(右)零因子环,如果对于任何 $a \in R$,都有$r_R (a) \neq 0~(l_R(a)\neq 0)$,而称一个环为强左(右)零因子环,如果$r_R(R)\neq 0~(l_R(R)\neq 0)$.Camillo和Nielson称一个环$R$为右有限零化环(简称RFA-环),如果$R$的每一个有限子集都有非零的右零化子.本文给出左零因子环的一些基本例子,探讨强左零因子环和RFA-环的扩张,并给出它们的等价刻画.     

离子液体在TiO2纳晶染料敏化太阳能电池中的应用

离子液体以其高稳定性、高电导率等特有的优点,成为众多领域中研究的热点。本文简单综述了离子液体的概念、结构及其在TiO2纳晶染料敏化电池的固、液态电解质中的应用,并对其应用前景进行了展望。     

Structure prediction of cyclic peptides by molecular dynamics + machine learning

Recent computational methods have made strides in discovering well-structured cyclic peptides that preferentially populate a single conformation. However, many successful cyclic-peptide therapeutics adopt multiple conformations in solution. In fact, the chameleonic properties of some cyclic peptides are likely responsible for their high cell membrane permeability. Thus, we require the ability to predict complete structural ensembles for cyclic peptides, including the majority of cyclic peptides that have broad structural ensembles, to significantly improve our ability to rationally design cyclic-peptide therapeutics. Here, we introduce the idea of using molecular dynamics simulation results to train machine learning models to enable efficient structure prediction for cyclic peptides. Using molecular dynamics simulation results for several hundred cyclic pentapeptides as the training datasets, we developed machine-learning models that can provide molecular dynamics simulation-quality predictions of structural ensembles for all the hundreds of thousands of sequences in the entire sequence space. The prediction for each individual cyclic peptide can be made using less than 1 second of computation time. Even for the most challenging classes of poorly structured cyclic peptides with broad conformational ensembles, our predictions were similar to those one would normally obtain only after running multiple days of explicit-solvent molecular dynamics simulations. The resulting method, termed StrEAMM (Structural Ensembles Achieved by Molecular Dynamics and Machine Learning), is the first technique capable of efficiently predicting complete structural ensembles of cyclic peptides without relying on additional molecular dynamics simulations, constituting a seven-order-of-magnitude improvement in speed while retaining the same accuracy as explicit-solvent simulations.

The StrEAMM method enables predicting the structural ensembles of cyclic peptides that adopt multiple conformations in solution.     

微波等离子体炬发射光谱法测定高温合金中非金属元素

研究了微波等离子体炬原子发射光谱(MPT-AES)法测定高温合金中非金属元素(As、B、P、Si)的分析方法,考察此方法对高温合金行业非金属检测需求的适应性。对镍基高温合金样品进行酸溶解处理,选择适用的微波等离子体炬分析谱线,进行检出限、精密度测定。4种非金属元素的检出限在0.03~0.12μg/mL,10次数据的相对标准偏差(RSD,n=10)为0.88%~1.9%,此方法可用于高温合金中非金属元素的测定。     

基于纠缠见证的路径纠缠微波检测方法

提出了一种基于纠缠见证的路径纠缠微波信号检测方法.路径纠缠微波是微波频段上的连续变量纠缠,介绍了利用微波压缩态和微波分束器制备路径纠缠微波的方法.根据部分转置正定判据以及2?2纠缠态密度矩阵的部分转置具有负本征值的性质,分别对常见的两种2?2纠缠进行了纠缠见证算符的构造,用于对两路信号是否为纠缠态进行判定.将连续变量纠缠的路径纠缠微波分解为大量2?2纠缠子系统叠加的纠缠态,证明其能够利用所构造的2?2纠缠见证算符来检测路径纠缠微波.同时分析了微波分束器的作用,并利用微波分束器设计了一种用于检测路径纠缠微波信号的实验方案,并在理论上分析了纠缠检测所得到的结果.结果表明,该方法能够有效检测路径纠缠微波信号,降低了检测的复杂度和计算量.本文的研究为纠缠微波的检测提供了思路.     

小分子给体/高分子受体型有机太阳能电池研究进展

有机太阳能电池具有低成本、柔性和质量轻等优势, 是一种有应用前景的光伏技术, 受到人们的广泛关注. 有机太阳能电池的光敏活性层通常由p-型有机半导体(包括小分子和高分子)与n-型有机半导体(包括小分子和高分子)共混而成. 小分子给体/高分子受体型有机太阳能电池具有形貌热稳定性优异的特点, 值得深入研究. 本综述旨在总结小分子给体/高分子受体型有机太阳能电池的研究进展, 分别介绍了基于酰亚胺基、氰基和含硼氮配位键(B←N)的高分子受体的活性层材料体系的发展状况. 在器件性能方面, 通过分子设计、相分离形貌调控, 改善了小分子给体/高分子受体的匹配性, 将该类电池的能量转换效率从最初的0.29%提升至目前的9.51%, 为性能的进一步提升总结了经验; 在稳定性方面, 基于该体系形貌热稳定性优异的特点, 开发出高温耐受型有机太阳能电池器件. 最后, 展望了小分子给体/高分子受体型有机太阳能电池的未来发展方向和前景.