TFSI钝化晶体硅表面性质的第一性原理研究

晶体硅表面钝化是高效率晶体硅太阳能电池的核心技术,直接影响晶体硅器件的性能。本文采用第一性原理方法研究了一种超强酸-双三氟甲基磺酰亚胺(TFSI)钝化晶体硅(001)表面。研究发现,TFSI的四氧原子结构能够与Si(001)表面Si原子有效成键,吸附能达到-5.124 eV。电子局域函数研究表明,TFSI的O原子与晶体硅表面的Si的成键类型为金属键。由态密度和电荷差分密度分析可知,Si表面原子的电子向TFSI转移,从而有效降低了Si表面的电子复合中心,有利于提高晶体硅的少子寿命。Bader电荷显示,伴随着TFSI钝化晶体硅表面的Si原子,表面Si原子电荷电量减少,而TFSI中的O原子和S原子电荷电量相应增加,进一步证明了TFSI钝化Si表面后的电子转移。该工作为第一性原理方法预测有机强酸钝化晶体硅表面的钝化效果提供了数据支撑。     

Progress in DNA Aptamers as Recognition Components for Protein Functional Regulation

Proteins play a central role in all domains of life, and precise regulation of their activity is essential for understanding the related biological processes and therapeutic functions. Nucleic acid aptamers, the molecular recognition components derived from systematic evolution of ligands by exponential enrichment(SELEX), can specifically identify proteins with antibody-like recognition characteristics and help to regulate their activity. This minireview covers the SELEX-based selection of protein-binding aptamers, membrane protein analytical techniques based on aptamer-mediated target recognition, aptamer-mediated functional regulation of proteins, including membrane receptors and non-membrane proteins(thrombin as a model), as well as the potential challenges and prospects regarding aptamer-mediated protein manipulation, aiming to supply some useful information for researchers in this field.     

A facile approach to fabricate and embed multifunctional nano ZnO into soap matrix and liquid cleansing products for enhanced antibacterial and photostability for health and hygiene applications

This research demonstrates, a facile approach to fabricate the nano ZnO system in an unique combination of surfactant-polyol-assembly (SPA) acting as a caging agent restricting the ZnO crystallite size in nano-regime. This SPA is suitable for health and hygiene products and such optimized technique is among the very few researches exploring the impact of embedding low concentrations of nano ZnO system into the matrix of sodium salt of long chain fatty acids (soap bar) and liquid cleansing personal care products. The fabricated nano ZnO in SPA and infused products were systematically characterized using various advanced and appropriate techniques. The hexagonal wurtzite structure of nano ZnO-SPA is evaluated based on XRD pattern which also exhibit an average crystallite size as 20.18 nm and high specific surface area as 52.99 m²/g. The SEM-supported morphological assessment confirms the formation of agglomerates of ultrafine ZnO rods and spherical particles. Novel nano ZnO having wideband gap energy (3.66 eV) embedded in soap bar act as a UV-blocker preventing the oxidation of unsaturated long chain fatty acids. Soap bar without ZnO experienced degradation and reduction in whiteness to 17.85% whereas 2.5 mg/g nano ZnO infused soap shows the reduction to 7.9% which clearly reflects the increased photostability of soap bar. The antibacterial efficacy of nano ZnO-SPA and infused products are investigated against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) by Zone of Inhibition (ZOI) and European standard EN:1276. Infused products exhibited high antibacterial efficacy up to 4.43 log reduction equivalent to >99.99% germ kill.     

改进的PNC方法及其在非线性偏微分方程多解问题中的应用

2017年，李昭祥等提出了一种偏牛顿-校正法（Partial Newton-Correction Method，简记为PNC方法），并利用它成功地计算出了三类非线性偏微分方程的多重不稳定解.本文在PNC方法的基础上，提出并发展了一种改进的PNC方法.首先，利用Nehari流形$\mathcal{N}$与零平凡解的可分离性，建立并证明了$\mathcal{N}$的某特殊子流形$\mathcal{M}$上的全局分离定理及其推广（即局部分离定理）.全局分离定理只跟非线性偏微分算子或相应的非线性泛函本身有关，而与具体的计算方法无关.对一些典型的非线性偏微分方程多解问题（比如，Henon方程问题），该全局分离定理的分离条件，经验证是成立的.另一个方面，通过修改或补充原辅助变换的定义，去掉了原辅助变换的奇异性；接着建立并证明了某些非线性偏微分方程问题的新未知解与该非线性偏微分算子零核空间的密切关系；在证明中，去掉了在原奇异变换下所需的标准收敛（standard convergence）假设.最后，计算实例与数值结果验证了改进的PNC方法的可行性和有效性；同时表明子流形$\mathcal{M}$与已知解的可分离性是PNC方法和本文新方法能成功找到多解的关键.     

Pattern transition and regulation in a subthalamopallidal network under electromagnetic effect

Although the significant roles of magnetic induction and electromagnetic radiation in the neural system have been widely studied, their influence on Parkinson's disease (PD) has yet to be well explored. By virtue of the magnetic flux variable, this paper studies the transition of firing patterns induced by magnetic induction and the regulation effect of external magnetic radiation on the firing activities of the subthalamopallidal network in basal ganglia. We find: (i) The network reproduces five typical waveforms corresponding to the severity of symptoms: weak cluster, episodic, continuous cluster, episodic, and continuous wave. (ii) Magnetic induction is a double-edged sword for the treatment of PD. Although the increase of magnetic coefficient may lead the physiological firing activity to transfer to pathological firing activity, it also can regulate the pathological intensity firing activity with excessive β-band power transferring to the physiological firing pattern with weak β-band power. (iii) External magnetic radiation could inhibit continuous tremulous firing and β-band power of subthalamic nucleus (STN), which means the severity of symptoms weakened. Especially, the bi-parameter plane of the regulation region shows that a short pulse period of magnetic radiation and a medium level of pulse percentage can well regulate pathological oscillation. This work helps to understand the firing activity of the subthalamopallidal network under electromagnetic effect. It may also provide insights into the mechanisms behind the electromagnetic therapy of PD-related firing activity.     

人教版高中化学教科书“研究与实践”栏目分析与实施策略*

对人教版高中化学教科书新设计的“研究与实践”栏目的主题内容、功能价值进行分析,就如何充分发挥该栏目的教学功能和价值,发展学生的化学学科核心素养,提出了创设教学情境线索、开发为研究性学习课题、开发为校本选修课程、开发为STEM课程等实施策略。     

基于2,5-二溴对苯二甲酸配体的锌/钴配合物合成、晶体结构及性质

将有机物2,5-二溴对苯二甲酸(H₂L₁)和2,2′-联吡啶(L₂)作为双配体,使用溶剂热法和七水合硫酸锌(ZnSO₄·7H₂O)、六水合硝酸钴(Co(NO₃)₂·6H₂O)分别反应,得到配合物[Zn(L₁)(L₂)(H₂O)]_n(1)和配合物[Co(L₁)(L₂)(H₂O)]_n(2)。采用单晶X射线衍射、元素分析、红外光谱、紫外光谱、荧光光谱、热重分析等测试方法对这两种物质进行分析研究。单晶测试结果表明配合物1是单斜晶系,以Zn²⁺配位连接L^2-₁与L₂形成一维链状结构,各条链在分子间氢键和π…π共轭作用下有规律地堆叠形成三维网络结构。配合物2是三斜晶系,Co1离子和Co1ⁱ离子由H₂L₁上的羧酸氧原子O4和O4ⁱ连接,形成双齿螯合的配位结构单元,以Co²⁺配位连接 L^2-₁和L₂形成二维网格结构,各层在O—H…O分子间氢键和范德瓦耳斯力作用下有规律的堆叠形成三维网络结构。配合物1和2均含有芳香杂环、羧基杂环和氮杂环,具有良好的荧光性质和热稳定性,最大发射波长分别为345 nm和333 nm。