分子蒸馏在多糖酯的分离纯化方面的应用

分子蒸馏是国际上一种新型的分离方法，它可以使一些常规蒸馏不能分离的物质实现分离。本文详细地比较了分子蒸馏和其它蒸馏方法的特点，并对分子蒸馏技术在糖多酯的分离纯化作了较为系统的介绍。     

共轭亚油酸几何异构体的形成机制

讨论了共轭亚油酸几何异构体的形成机制。通过半经验量子化学方法AM1计算了9c,11c CLA到9c,11t CLA扭转二面角与生成热之间的关系。指出前驱物中9，12位非共轭双键的构型、反应温度、反应时间决定了产物中CLA的各种几何异构体的含量。     

关于噪声评价用语的研究

在中国进行了关于噪声评价用语的社会调查,250名大学生用选择描述法和SD法等两种实验方法,用事先准备好的调查表,对4个声级的6种声源进行了评价.通过对实验数据的统计分析处理得到了以下结果: 1.声源可被分为高声级噪声、低声级噪声、语言声和音乐声等四类. 2.根据对声音的评价结果、所用的形容词也可被分为四类.对于不同类别的声源,要用不同类别的形容词来进行描述. 3.形容词“大的”一般是用于描述声级高的声音,不大用于描述噪声.“喧闹的”和“讨厌的”是贬义词,一般用来描述人对噪声的感受. 4.用选择描述法做评价声音实验比用SD法能获得更多的信息. 5.Cluster分析法、数量化理论Ⅳ类和Biplot分析法是处理声音评价实验数据的有效手段.     

Reduction potentials and acidity constants of Mn superoxide dismutase calculated by QM/MM free-energy methods

We used two theoretical methods to estimate reduction potentials and acidity constants in Mn superoxide dismutase (MnSOD), namely combined quantum mechanical and molecular mechanics (QM/MM) thermodynamic cycle perturbation (QTCP) and the QM/MM-PBSA approach. In the latter, QM/MM energies are combined with continuum solvation energies calculated by solving the Poisson-Boltzmann equation (PB) or by the generalised Born approach (GB) and non-polar solvation energies calculated from the solvent-exposed surface area. We show that using the QTCP method, we can obtain accurate and precise estimates of the proton-coupled reduction potential for MnSOD, 0.30±0.01 V, which compares favourably with experimental estimates of 0.26-0.40 V. However, the calculated potentials depend strongly on the DFT functional used: The B3LYP functional gives 0.6 V more positive potentials than the PBE functional. The QM/MM-PBSA approach leads to somewhat too high reduction potentials for the coupled reaction and the results depend on the solvation model used. For reactions involving a change in the net charge of the metal site, the corresponding results differ by up to 1.3 V or 24 pK(a) units, rendering the QM/MM-PBSA method useless to determine absolute potentials. However, it may still be useful to estimate relative shifts, although the QTCP method is expected to be more accurate.     

Many-particle dynamics and intershell effects in Wigner molecules

We apply classical molecular dynamics within the velocity Verlet algorithm to examine the formation dynamics of Wigner crystals in two-dimensional harmonic oscillators. Using a large ensemble of initial conditions as well as different freezing mechanisms, we obtain reliable information on the energies and probabilities of stable and metastable configurations, their formation dynamics, and their stability. Wigner-crystal configurations of up to 30 particles are presented and the dynamics of transition processes, e.g., intershell effects, are analyzed.     

Ab initio study of magnetoelectricity in Fe/BaTiO3: the effects of n-doped perovskite interfaces

On the basis of ab initio calculations we study the interfacial magnetoelectric effect in a prototypical biferroic Fe(L)/XO2/BaO/BaTiO3(001) (X = Ti, V, Co), with an Fe thickness L ≤ 2 monolayers. We anticipate that the use of the n-type perovskite termination instead of nominally neutral TiO2 may enhance magnetoelectricity in the system when its magnetization is robustly changed by substrate-polarization reversal.     

新高考背景下高中物理学科地位探讨——基于“3+3”和“3+1+2”选考模式的分析

2014年启动的新一轮高考改革对先行高考制度带来了一定的变化,不分文理科,在全国统一考试基础上,注重学生兴趣和高校选拔人才的要求,向学生和高等院校提供了更多的选择权.新高考启动以来,在短短6年内不断总结经验、探索与完善,前后试行了“3+3”和“3+1+2”两种选考模式,在不同的选考模式下,高中物理学科在多个选考科目中呈现出一定的优势.通过分析新高考相关文献资料,探讨两种选考模式下的高中物理学科地位,为新高考下的高中物理教学起到一定的指导作用,从而让高中物理教学更好地适应新高考的变化趋势.     

Measuring the tilt of primordial gravitational-wave power spectrum from observations

Size effect on thermodynamics and diffusion of deuterium in nano-sized vanadium(V) layers is studied. Critical temperature(Tc)for deuterium phase transition is found to decrease with the inverse thickness of V layers and the thermodynamic factor increases as V thickness decreases. These effects are related to the deuterium-deuterium(D-D) interaction change versus V thickness,which experimentally proves that the D-D interaction plays the main contribution to the previously observed V size effect on deuterium chemical diffusion coefficients(D_c). The self-diffusion coefficients(D_s) are obtained through correcting D_c with the thermodynamic factors. It is found that the D_s are similar in 14 and 28 monolayers of V while slightly larger D_s are observed at high concentrations in 14 atomic layers. The weak site blocking effect in the interface is argued to be the main contribution to the observed size effect on D_s.