用准经典轨迹的理论方法研究H+ +H2反应

在新的势能面上,用准经典轨迹的方法对H H2反应体系进行了动力学研究．理论计算的结果发现,这个反应体系的前向和后向的角分布基本是对称的．同时还给出了在不同碰撞能下这个反应体系的转动态的分布情况．在碰撞能的从0．124到1．424 eV时,反应H H2的积分截面是随着碰撞能的增加而逐渐降低的．而且理论计算结果与实验结果也符合的非常好．     

带电纳米颗粒与相分离的带电生物膜之间相互作用的分子模拟

纳米颗粒在纳米医药、细胞成像等领域有着非常广泛的应用,深入理解纳米颗粒与生物膜之间相互作用的微观机制是纳米颗粒合成与应用的重要基础.本文采用粗粒化分子动力学模拟的方法研究了带电配体包裹的金纳米颗粒与相分离的带电生物膜之间的相互作用.结果表明,通过改变金纳米颗粒表面的配体密度、配体带电种类和比例,以及膜内带电脂分子的种类,可以方便地调控纳米颗粒在膜表面或膜内停留的位置和状态.进一步从自由能的角度分析了带电纳米颗粒与带电生物膜之间相互作用的微观物理机制.本文对纳米粒子在纳米医药、细胞成像等领域的应用具有一定的理论参考意义.     

Dynamics of cooperative emissions in a cascade three-level molecular system driven by an ultrashort laser pulse

This paper investigates the dynamics of cooperative emissions in a cascade three-level system driven by an ultra, short laser pulse by solving numerically the full-wave Maxwell-Bloch equations. The 4, 4＇-bis（dimethylamino） stilbene molecule is used as the model molecule because of its strong two-photon absorption property. The two-colour cooperative emissions are studied as functions of molecular number density and dephasing rate of the dipole coherence. The propagation effects on the evolution of the cooperative radiations are also taken into account. The cooperative radiations are enhanced for large number density of the molecule, while the fast dephasing of the dipole coherence reduces the intensity of the cooperative radiations and delays the emission times or even inhibits the formation of the emissions. The delay time of the radiation decreases with the increase of the molecular number density and the propagation distance.     

Asymmetric Synthesis, Antifungal Activity and Molecular Modeling of Iodiconazole Isomers

Iodiconazole is a novel antifungal agent that was developed in its racemic form. In order to investigate the ef- fects of the chiral center on the antifungal activity, R- and S-isomers of iodiconazole were prepared on the basis of the asymmetric Sharpless epoxidation. （S）-Iodiconazole was proved to have better antifungal activity than the （R）- isomer. The binding modes of the two isomers with lanosterol 14~z-demethylase were clarified by molecular dock- ing.     

Theoretical Insights into Intermolecular Hydrogen-Bonding Strengthening in Fluorenone-Methanol Complexes Induced by Electronic Excitation and Bulk Solvent Effect

This work presents a theoretical insight into the variation of the site-specific intermolecular hydrogen-bonding （HB）, formed between C=O group of fluorenone （FN） and O-H groups of methanol （MeOL） molecules, induced by both the electronic excitation and the bulk solvent effect. Through the calculation of molecular ground- and excited-state properties, we not only demonstrate the characters of HB strengthening induced by electronic excitation and the bulk solvent effect but also reveal the underlying physical mechanism which leads to the HB variation. The strengthening of the intermolecular HB in electronically excited states and in liquid solution is characterized by the reduced HB bond-lengths and the red-shift IR spectra accompanied by the increasing intensities of IR absorption corresponding to the characteristic vibrational modes of the O-H and C--O stretching. The HB strengthening in the excited electronic states and in solution mainly arises from the charge redistribution of the FN molecule induced by the electronic excitation and bulk solvent instead of the intermolecular charge transfer. The charge redistribution of the solute molecule increases the partial dipole moment of FN molecule and the FN-MeOL intermolecular interaction, which subsequently leads to the HB strengthening. With the bulk solvent effect getting involved, the theoretical IR spectra of HBed FN-MeOL complexes agree much better with the experiments than those of gas-phase FN-MeOL dimer. All the calculations are carried out based on our developed analytical approaches for the first and second energy derivatives of excited electronic state within the time-dependent density functional theory.     

基于机械-化学的方法在硅表面制造功能化结构

"利用机械与化学结合的方法在芳烃重氮盐溶液中用金刚石刀具切削硅片,使得芳香烃分子和硅之间以共价键连接,实现了对硅片的"成形并功能化"的一步完成．研究了在大气环境如何利用金刚石刀具在硅表面加工出表面质量较好的微结构,为下一步在溶液中"成形并功能化"硅提供好的基底．在溶液中对硅表面进行可控自组装实验,初步研究了切削速度和组装时间对切削处生成自组装膜质量的影响,总结出较适合膜生长的参数．用X射线光电子能谱对自组装膜进行了检测,用扫描电子显微镜和原子力显微镜对自组装膜的表面形貌进行了表征,并用原子力显微镜对自     

基于CS-GO/AgNPs氯酚分子印迹电化学传感器的构建

以2,4-二氯苯酚(2,4-DCP)为模板分子,吡咯(Py)为功能单体,协同壳聚糖-银纳米粒子氧化石墨烯(CS-GO/AgNPs)复合材料增强电导性,在玻碳电极(GCE)表面制备分子印迹膜,构建了2,4-DCP分子印迹电化学传感器(2,4-DCP-MIECS)并用于水环境中氯酚的特异性识别与检测。通过透射电子显微镜(TEM)、X射线衍射仪(XRD)对GO/AgNPs复合材料进行分析表征,采用循环伏安法(CV)、交流阻抗法(EIS)对电化学传感器进行性能表征。采用差分脉冲伏安法(DPV)对2,4-DCP进行检测,该电化学传感器的线性范围为1.0～1.0×10~3pmol/L,检出限为0.1 pmol/L,该传感器已用于水样品中2,4-DCP的检测。     

物理,给了我一双发现美的眼睛

物理学女博士生是什么样子的?上大学的时候,自己会有很多的幻想和憧憬,比如天天穿着实验服穿梭于各个实验室之间,探索着肉眼看不到的纳米世界或者浩瀚广阔的天体、宇宙,没准儿还可以发现一些新奇的现象并且给出科学的解释,就像科幻电影里的科学天才一般,浑身上下都散发着智慧之美。大概因为大学时候自己一直有着这样的愿望和想象,所以从大一到大三,我最常待着的地方     

飞秒激光参数对三态阶跃型分子Autler-Townes分裂的影响

利用三态模型和含时波包法, 研究了K₂分子在强飞秒泵浦-探测激光场中泵浦/探测场强、波长对光电子能谱Autler-Townes(AT)分裂的影响．通过分别改变两激光场的场强或者波长预测AT峰移和间距,并且首次量化了AT分裂的峰移和间距．光电子能谱在共振时显示为对称双峰,失谐时为非对称双峰。AT分裂间距随泵浦场强增大而增大,但不因探测场强改变而改变．     

碳化硅晶体产生中红外飞秒激光研究获进展

中红外激光(3~5μm)在环境监控、气体分子识别、相干断层成像、军事等领域有着重要应用,特别是近年来在高次谐波产生单个阿秒脉冲的研究中,由于周期量级中红外飞秒激光能获得更高截止能量的谐波阶次,有望获得更短的阿秒脉冲和更高的时间分辨率,因此倍受人们的青睐。但受限于激光增益介质,目前较难在室温下直接获得中红外波段的飞秒激光,为此广泛应用的方案是基于非线性晶