应用CoMFA研究磺酰脲类化合物的三维构效关系

用比较分子力场分析 (CoMFA)方法研究了磺酰脲类除草剂结构与活性的三维定量构效关系 ( 3D QSAR) ,并在此基础上对原有分子结构进行修饰改造 ,以获得较高活性的化合物 .并在三维等值线图的基础上得到了此类除草剂作用靶标ALS酶的模拟作用模型 ,为进一步合成出全新结构的ALS酶抑制剂的先导化合物提供了有益的启示和帮助 .     

原卟啉原Ⅸ的构象分析

在合理药物设计方法中,当靶标酶的三维结构未知时,对其底物进行构象分析,特别是确定其活性构象,对阐明靶标酶活性中心的空间形状和作用位点具有十分重要的意义.我们曾利用距离比较法确定了原卟啉原氧化酶的底物-原卟啉原Ⅸ的活性构象,本文从构象分析的角度对4种不同构象的原卟啉原Ⅸ分子与二苯醚类分子的晶体学构象进行了几何参数的比较和分析,结果进一步证实了距离比较法所确定的活性构象更为可靠.     

基于三维集流体的无枝晶锂金属负极

随着电化学储能市场的迅猛发展, 当前商用锂离子电池难以满足人们对高能量密度储能器件的需求. 锂金属具有高比容量和低氧化还原电位等优点, 被认为是下一代二次电池的理想负极材料. 然而, 锂金属负极在充放电过程中会出现体积变化大、 枝晶生长、 界面不稳定等问题, 严重阻碍了其在二次电池中的实际应用. 三维多孔材料具有骨架/空间互穿网络结构、 比表面积大、 孔隙发达和机械性能好等物理特性, 用作金属锂负极的集流体, 在锂沉积/溶解过程中可以起到降低局部有效电流密度、 均匀电场分布和降低锂离子浓度梯度的作用, 有望实现锂的均匀成核和无枝晶沉积, 同时抑制了电极的体积膨胀. 尽管有关三维集流体的研究报道不断出现, 但综合系统评价现有各种三维集流体体系的工作鲜见报道. 本文聚焦锂金属负极三维集流体的构建及应用研究进展, 首先分析了三维集流体抑制锂枝晶生长的基本原理及局限性, 继而重点关注了三维集流体的结构调控、 表面改性和功能化等应对策略对锂成核、 沉积过程的影响, 并对不同材质三维集流体的优缺点进行了归纳总结. 最后, 面向实用化, 分析并展望了三维集流体应用于锂金属电池的发展前景.     

ICP-AES测定土壤勘查地球化学样品中钼的不确定度评定

采用电感耦合等离子体发射光谱法对土壤勘查地球化学样品中的钼进行测定,并对测量结果进行不确定度评定. 分析了影响测量不确定度的主要来源,对测定全过程的重复性、样品称量、拟合曲线、标准溶液、玻璃量具及仪器等影响不确定度的因素进行分析,按JJF l059—1999《测量不确定度评定与表示》的规定进行评定,并计算出扩展不确定度,使结果的表达更加客观和真实.     

苯基吡咯类芳香化酶抑制剂的3D-QSAR及分子对接研究

用分子对接和三维全息原子场作用矢量方法对36个来曲唑类衍生物和34个阿那曲唑类衍生物与芳香化酶的作用模式进行了研究,建立了三维定量构效关系模型,并在分子水平上阐述了其结合机制.运用多元线性回归(MLR)建模,同时采用内部及外部双重验证的办法对所得模型稳定性能进行深入分析和检验.MLR建模的复相关系数(Rcum)、留一法交互校验复相关系数(QCV)和外部样本校验复相关系数(Qext)分别为0.863,0.782,0.796和0.931,0.825和0.641.预测模型具有良好的稳定性和预测能力.采用AutoDock4.2软件对药物与受体之间的结合方式进行了研究.运用这些信息能为进一步设计合成强效芳香化酶抑制剂,或筛选潜在的具有更强抑制活性的天然化合物提供帮助.     

自组装方法与三维光子晶体制作

光子晶体,特别是三维光子晶体,可能成为信息处理和通信等领域的新型功能材料.光子晶体的制作方法可分为"自上而下"的物理方法和"自下而上"的化学自组装方法.化学自组装方法是制作三维光子晶体最为经济有效的方法.本文在阐述自组装方法的种类、一般过程、优点和不足等内容的基础上,分别分析和总结了带有各种功能缺陷的三维光子晶体的制作,这些缺陷主要包括线缺陷、面缺陷和点缺陷.从研究中可以看出,化学自组装方法通常需要结合其他方法才能实现缺陷的嵌入.近些年,三维光子晶体制作在材料选取、结构设计和方法改进等方面都有一些最新进展,本文对此进行了较为详尽的评述,并对我们课题组的研究进行了总结.最后对光子晶体的研究和制作方向进行了展望.     

氧弹量热仪测定生物质原料热值不确定度的评定

生物质原料是重要的环保燃料,具有成本低、来源广、热值高的特点.本文利用标准型氧弹量热仪测定牛粪、猪粪、玉米秸秆和水稻秸秆等生物质原料热值,并对试验结果进行不确定度影响分析,以表征合理地赋予被测量值的分散性,为资源化利用农业废弃物提供依据.本文构建了不确定度评定数学模型,逐层对不确定度来源进行分析和评定,并对各不确定度分...     

基于斜光刻技术的SU-8胶三维微阵列结构制备

利用斜光刻技术替代传统的直光刻技术在相同底面积的基础上增大微阵列比表面积制备了高比表面积三维微阵列结构,.首先,利用MATLAB仿真对微阵列排布方式进行分析,确定最佳单个柱体宽度及阵列间距.实验中,采用两次甩胶法将SU-8光刻胶均匀旋涂在2寸硅基底上,甩胶转速设为1500r/min,旋涂时间设为35 s;分别置于65℃烘台上保持20 min和95℃烘台上保持70 min进行两次前烘处理;随后进行双向斜曝光,微柱宽度为20 μm,阵列间距为30 μm,光刻角度为20°.最后,再通过高低温后烘处理并显影30 min成功制备出了结构稳定的“Ⅹ”型三维微阵列结构.     

咪唑并吡啶类化合物结构及PDE抑制活性的三维构效关系研究

对咪唑并吡啶类化合物作为环核苷酸磷酸二酯酶(PDE)的抑制剂的抑制活性进行了比较分子力场分析.结果表明,立体效应和静电作用场是描述对PDE抑制活性和进行结构性能关系研究的最重要的结构参数,提出了对该类化合物进行结构修饰的方法,并由新建立的三维定量构效关系模型对该类化合物的PDE抑制活性进行了预报.     

滴定剂终点体积的确定方法及比较

滴定剂终点体积的确定是滴定分析工作的核心,以重铬酸钾滴定亚铁为例,重点针对手动电位滴定法的3种确定终点体积的方法（E-V曲线法、ΔE/ΔV-V曲线和Δ2E/ΔV2-曲线）,进行了具体作图计算处理。引导学生比较了手动电位滴定法、自动电位滴定法和指示剂法3类方法的滴定结果,并对其结果进行了深刻的分析。将确定终点体积的方法连成一个体系,可以帮助学生深刻理解方法原理和计算处理方法,通过比较可以加深理解滴定剂终点体积确定方法的选择。     

Molecular dynamics study of gas hydrate formation

Long-time-scale molecular dynamics simulations are presented of the spontaneous formation of methane hydrate at a methane/liquid water interface. The water film was prepared at 300 K, 30 bar and showed no significant hydrate order. On crash cooling to 250 K, 300 bar (about 20 K subcooling), the system showed a rapid growth of hydrate clusters. Contrary to popular models for hydrate nucleation, the clusters formed first as two-dimensional arrangements and only later into three-dimensional cage structures; the results are, however, consistent with the local order model proposed recently. The hydrate clusters showed clear signatures of the type II hydrate structure even though the type I structure is the thermodynamically stable form for methane hydrate; this is in accord with the results of recent diffraction experiments.     

光学相干层析技术在法庭科学中的新应用

光学影像技术是法庭科学物证检验分析的重要技术手段，具有无损、原位、快速等优势。近年来，随着光学影像技术的不断发展，一些新技术、新方法不断被引入法庭科学领域并付诸应用。光学相干层析技术（简称OCT技术）是一种光学断层成像技术，具有无损、高分辨、快速、断层成像的特点，特别是其可以无损地得到材料或生物组织内部的结构信息，突破了传统二维成像只能进行物质表面分析的局限，因此可成为一种很有前景的新型法庭科学光学影像技术。本文首先介绍了自主搭建的一套三维OCT成像系统，并着重介绍了基于该系统应用于法庭科学油漆物证检验、胶带指纹显现和毛囊特征分析等方面的研究。结果表明，OCT技术非常适合用于法庭科学物证检验分析，作为其他检验的先导技术手段，获取样品内部信息，提取新型光学特征参数。由于其采用光纤化技术，还有望实现便携化、小型化，在现场勘查中开展相关应用。     

化学品安全知识与应急科普宣传研究

Based on the theme of "chemical awareness and safety accident response capability", this paper conducts a questionnaire survey for college students. In response to the survey results, scientific, popular, and novel offline activities/online publicity will be used to popularize chemical basics, relevant laws and regulations, and chemical safety accident emergency response methods for university students. The aim is to improve the level of understanding of various types of chemicals among college students. In the event of sudden chemical safety incidents, corrective measures can be taken, and useful information can be accurately identified after a chemical accident.     

Three-dimensional colloidal crystal-assisted lithography for two-dimensional patterned arrays

In this paper, we report our recent work on preparing two-dimensional patterned microstructure arrays using three-dimensional colloidal crystals as templates, namely, colloidal crystal-assisted lithography. Two alternative processes are described and involved in colloidal crystal-assisted lithography. One is based upon imprinting the polymer films with three-dimensional silica colloidal crystals, and the other is based upon chemically depositing Ag microstructures on Au substrates covered by polymer colloidal crystals. By varying the experimental conditions in the colloidal crystal-assisted lithography process, we can intentionally control the morphologies of the resulting microstructures. The resultant Ag-coated Au substrates can be used as surface-enhanced Raman scattering substrates, and they would provide an ideal system for the mechanism study of surface-enhanced Raman scattering. We expect that colloidal crystal-assisted lithography will be a versatile approach which can be applied to patterning other materials such as functional molecules, polymers, oxides, and metals.     

Self-assembly of patchy particles into diamond structures through molecular mimicry

Fabrication of diamond structures by self-assembly is a fundamental challenge in making three-dimensional photonic crystals. We simulate a system of model hard particles with attractive patches and show that they can self-assemble into a diamond structure from an initially disordered state. We quantify the extent to which the formation of the diamond structure can be facilitated by "seeding" the system with small diamond crystallites or by introducing a rotation interaction to mimic a carbon-carbon antibonding interaction. Our results suggest patchy particles may serve as colloidal "atoms" and "molecules" for the bottom-up self-assembly of three-dimensional crystals.     

Three-dimensional electronic spectroscopy of excitons in asymmetric double quantum wells

We demonstrate three-dimensional (3D) electronic spectroscopy of excitons in a double quantum well system using a three-dimensional phase retrieval algorithm to obtain the phase information that is lost in the measurement of intensities. By extending the analysis of two-dimensional spectroscopy to three dimensions, contributions from different quantum mechanical pathways can be further separated allowing greater insight into the mechanisms responsible for the observed peaks. By examining different slices of the complete three-dimensional spectrum, not only can the relative amplitudes be determined, but the peak shapes can also be analysed to reveal further details of the interactions with the environment and inhomogeneous broadening. We apply this technique to study the coupling between two coupled quantum wells, 5.7 nm and 8 nm wide, separated by a 4 nm barrier. Coupling between the heavy-hole excitons of each well results in a circular cross-peak indicating no correlation of the inhomogeneous broadening. An additional cross-peak is isolated in the 3D spectrum which is elongated in the diagonal direction indicating correlated inhomogeneous broadening. This is attributed to coupling of the excitons involving the two delocalised light-hole states and the electron state localised on the wide well. The attribution of this peak and the analysis of the peak shapes is supported by numerical simulations of the electron and hole wavefunctions and the three-dimensional spectrum based on a density matrix approach. An additional benefit of extending the phase retrieval algorithm from two to three dimensions is that it becomes substantially more reliable and less susceptible to noise as a result of the more extensive use of a priori information.     

基于Unity 3D的气相色谱仪虚拟仿真实验系统的构建

虚拟仿真技术被广泛认为是一项重大技术进步,可以提供一种新颖的教学方式,能促进化学学习,打破传统教育方法的限制。三维交互式的气相色谱仪虚拟仿真实验系统使用当前主流的Unity 3D软件作为系统的主要开发工具。构建的系统主要包含仪器的动态原理展示、三维结构展示及仿真实验3部分。系统中的模型全部采用三维设计,场景逼真,能够全方位地向使用者展现真实仪器的外形及内部结构,令使用者如同置身于真实实验室中,获得身临其境的操作体验,从而更容易学习和掌握仪器组成、工作原理及相关的实验技能。系统不仅满足了仪器培训和化学实验教学的基本需求,而且对虚拟仿真技术在化学中的应用起了示范效应和推广作用。     

Quasibinary amorphous phase in a three-dimensional system of particles with repulsive-shoulder interactions

We report a computer-simulation study of the equilibrium phase diagram of a three-dimensional system of particles with a repulsive-step potential. Using free-energy calculations, we have determined the equilibrium phase diagram of this system. At low temperatures, we observe a number of distinct crystal phases. However, under certain conditions the system undergoes a glass transition in a regime where the liquid appears thermodynamically stable. We argue that the appearance of this amorphous low-temperature phase can be understood by viewing this one-component system as a quasibinary mixture.     

Source term estimation using air concentration measurements during nuclear accident

The focus of this paper is locating and quantifying the diffusion source of ¹³⁷Cs by using observation data collected from monitoring stations. The estimation method is firstly tested in synthetic experiments and then verified with real ¹³⁷Cs concentration data of Fukushima accident. An atmospheric dispersion simulation system is used to support particle diffusion model. Besides, ridge regression is applied to calculate release rate. In terms of location estimation, posterior function of the source location can be deduced according to Bayesian inference. particle swarm optimization (PSO) method is implemented to locate diffusion source.     

Preliminary studies into profiling DNA recovered from a radiation or radioactivity incident

The examination and profiling of human DNA recovered from a scene of crime is an essential aspect of criminal investigations. However, it is currently not known whether DNA recovered from a scene where an ionising radiation source or radioactive contamination is present can be successfully profiled. The direct examination and analysis of radioactively contaminated DNA has not been widely explored using the current procedures employed by forensic service providers. As a result, AWE is putting in place an extensive research and development programme to better understand the effects that radiation has on the ability to profile human DNA, and assess the associated retention of different radioactive contaminants within each step of the profiling procedure. A summary will be provided on the aims of this project and progress that has been made to date; together with a discussion of the lessons that have been learnt during the course of the programme’s development.