Direct determination of discrete harmonic bath parameters from molecular dynamics simulations

We present a direct procedure for determining the parameters of a discrete harmonic bath modeling the influence of a complex condensed phase environment on the system of interest. The procedure employs an efficient discretization of the spectral density into modes that correspond to equal fractions of the reorganization energy. The new procedure uses directly the classical correlation function (available from molecular dynamics calculations) as input, avoiding numerical computation of the spectral density by means of a discrete Fourier transform. Convergence is obtained using a shorter time length of the correlation function, leading to significant computational savings. © 2016 Wiley Periodicals, Inc.     

加强助教培训和管理工作,提高化学实验教学质量

介绍了中国科学技术大学化学实验教学中心在实验助教培训和管理方面所开展的举措,从助教申请及培训流程、教学方法与技巧、考核制度、奖励措施等方面展开论述,分析了实验助教在本科实验教学中的作用,以及目前实验助教制度中存在的一些问题和解决方法。     

双眼视功能训练对视疲劳的治疗效果

目的研究分析双眼视功能训练对视疲劳的治疗效果。方法选择2014年9月至2016年9月期间佛山华厦眼科医院接收的视疲劳患者82例作为研究对象,采用症状问卷调查患者疲劳症状,对患者进行眼科检查、双眼视功能检查、屈光检查,根据患者实际情况予以视功能训练,观察训练效果。结果 82例患者中,完成训练患者71例,未完成训练患者11例;完成训练中,显效50例、有效13例、无效8例,治疗有效率为88.73%(63/71);19岁以下患者未完成训练人数较多,29岁以下患者治疗有效率比≥30岁患者高。结论双眼视功能训练在视疲劳的治疗中具有较高的临床应用价值,能有效改善患者的视功能,值得推广应用。     

哈尔滨市冬季PM_(2.5)与影响要素的相关分析

运用相关性分析方法,研究哈尔滨市PM_(2.5)质量浓度与主要空气污染物及气象因素之间的相关关系.建立PM_(2.5)与影响其质量浓度变化的因素的单因变量的偏最小二乘回归分析(PLS1)模型,模型拟合良好,由模型知CO是导致PM_(2.5)质量浓度升高的主要因素.运用通径分析方法,研究解释变量对因变量的直接影响、通过其他解释变量对因变量的间接影响以及各解释变量的对因变量的协同作用.结果表明,各解释变量对PM_(2.5)质量浓度变化的总作用从大到小依次为:CO、PM_(10)、NO_2、风速、湿度、SO_2.     

浅析老龄经济中的税收政策

本文放宽人口结构平稳假设,将总人口增长率与劳动人口增长率之差定义为老龄化率,在此基础上构建老龄经济模型,分析税收政策对老龄经济的影响。基于一定假设,老龄经济存在鞍型收敛路径,平衡增长路径上的人均收入增长率取决于技术进步率与老龄化率之差,技术进步率在积极应对人口老龄化方面至关重要。从税收角度看,资产收入税与企业利润税对老龄经济的扭曲程度较高,而劳动收入税与消费税的扭曲程度相对较低。通过削减政府支出与调整税收结构,减税不仅可以提高均衡的资本水平,若能够激励经济主体积极创新,还将会提高平衡路径上人均收入的增长速度。一定条件下,老龄经济中将会存在正的最优税率。     

The Pathmox approach for PLS path modeling: Discovering which constructs differentiate segments

The problem of heterogeneity represents a very important issue in the decision‐making process. Furthermore, it has become common practice in the context of marketing research to assume that different population parameters are possible depending on sociodemographic and psycho‐demographic variables such as age, gender, and social status. In recent decades, numerous approaches have been proposed with the aim of involving heterogeneity in the parameter estimation procedures. In partial least squares path modeling, the common practice consists of achieving a global measurement of the differences arising from heterogeneity. This leaves the analyst with the important task of detecting, a posteriori, which are the causal relationships (ie, path coefficients) that produce changes in the model. This is the case in Pathmox analysis, which solves the heterogeneity problem by building a binary tree to detect those segments of population that cause the heterogeneity. In this article, we propose extending the same Pathmox methodology to asses which particular endogenous equation of the structural model and which path coefficients are responsible of the difference.     

Angular and energy dependences of the surface excitation parameter for semiconducting III-V compounds

Sum-rule-constrained extended Drude dielectric functions were used to study surface excitations generated by energetic electrons moving across surfaces of semiconducting III-V compounds. Parameters in the dielectric functions were determined from fits to experimental optical data and electron energy-loss spectra. Electron inelastic mean free paths (IMFPs) in GaN, GaP, GaAs, GaSb, InAs and InSb were calculated for electron energies between 200 and 2000 eV, and the results were found to follow the simple formula, i.e., λ = kE^p, where λ is the IMFP and E is the electron energy. Surface excitation parameters (SEPs), which describe the total probability of surface excitations by electrons crossing the surface and travelling in vacuum, were also calculated for different electron energies and crossing angles. The SEP was found to follow the simple formula, i.e., , where P_s is the SEP and α is the crossing angle relative to the surface normal.     

无机化学课程设置创新型作业的思考与实践

在无机化学教学中设置了旨在提高学生创新意识、激发学生创新思维的创新型作业——无机化学创新大作业,类型包括文献综述、知识拓展、创新追踪、理论应用、总结类比、概括归纳、学科渗透等。