具有好的溶解性和高的热稳定性的富勒烯-苝化合物的合成

在氩气保护下,利用N-(正丁基)-N’(4-甲酰基苯氧戊基)-1．6,7,12-四-(4-叔丁基苯氧基)-3,4,9,10-苝酰亚胺和N-甲基甘氨酸产生的亚胺叶立德与富勒烯反应,合成了含富勒烯的苝化合物,用NMR、FT—IR、UV-Vis及TGA等方法对其结构和性能进行了表征和测试。研究结果表明此类化合物具有好的溶解性和高的热稳定性。     

酯的水解实验的改进

该文对现行的高中化学 (试验修订本 )第二册中关于乙酸乙酯水解实验的不足之处进行了分析,并提出了改进的方法,对其实验内容和实验效果进行了讨论。     

基于压力的速率方程的应用

通过具体实例说明对于气相反应,使用基于压力的速率方程解题比使用基于浓度的速率方程更直接﹑更简便。总结了具有简单级数的反应的基于压力的速率方程及其特征。     

基于环糊精的农药吸附剂的研究进展

农药的研发与使用极大地提高了农作物的产量,为解决人类温饱、改善人类生活品质做出了贡献。但是,农药广泛残留于农副产品以及土壤和水体中,造成的污染日趋严重。残留的农药通常具有微量致毒、难生物降解、生物累积等特性,对生物健康与生态系统造成了巨大威胁。高效检测微量农药、减小污染危害是亟待解决的问题。吸附法具有成本低、操作简单、稳定性强、可重复性强的特点,在农药分离预富集领域得到了广泛关注。作为一种常用的农药吸附剂材料,环糊精是一类具有空腔的超分子化合物,能够作为主体通过主客体作用形成包合物;另外,可以通过醚化、酯化、氧化等化学反应对环糊精进行后修饰以提高其吸附性能。疏水作用、静电作用、范德华力、氢键作用、立体效应协同促进对农药的吸附。环糊精在农药吸附领域已经取得了一定进展,但是目前还没有基于环糊精的农药吸附剂的综述。该文针对杀菌剂、杀虫剂、除草剂、植物生长调节剂这4类农药,系统性地评述了基于环糊精的农药吸附剂的制备、吸附机理及应用,目前存在个别吸附剂吸附容量不高、降解机理不明确、降解产物对环境不友好、容易造成二次污染的问题,研发高吸附容量、易回收、易分离、易再生的基于环糊精的农药吸附剂是未来的主要研究方向。     

地球的内部可能是湿润的

在地球的低层地幔下 ,可能存在着比现在的海洋还要多 4倍的水 ,这是日本工业大学的Ｍ .Ｍｕｒａｋａｍｉ和他的同事们最近估测出来的。日本地球科学家们利用了一种多功能钻探仪 ,通过对 3种据信包含低层地幔中在高温高压下生成的主要矿物组成的分析后 ,得到了这个结论。这 3种矿物是 :Ｍｇ ｐｅｒｏｖｓｋｉｔｅ ,Ｃａ ｐｅｒｏｖｓｋｉｔｅ和Ｍａｇｎｅｓｉｏｗ櫣ｓｔｉｔｅ。再利用ＳＩＭＳ对矿物中溶解的氢的含量进行测量 ,矿物学家认为氢是水的标记。发现这3种矿物的含水量都相当可观 ,大约在 0 .2 %至 0 .4 %(重量比率 )之间。用红外…     

基于Matlab的二元共聚合反应的竞聚率的求解

以直线交叉法为依据,根据最小二乘原理,采用Matlab GUI工具设计了一款用于计算二元共聚合反应竞聚率的图形用户程序。与传统的求解竞聚率方法相比,该图形用户程序具有设计原理简单、计算快捷的特点;同时程序提供界面简洁、交互友好的数据输入平台,实用性强。实际应用表明:采用该款图形用户程序所测得的数据与微机动态搜索法、Tidwell-Mortimer法相近,而比采用斜率截距法计算竞聚率的最小差方和更小,并且也避免了采用斜率截距法由于所用方程的非对称性造成的计算结果的不一致性。     

铁的吸氧腐蚀实验的改进

正1问题的提出化学实验是化学教学的生命线,在课堂教学中发挥着重要的认识论功能、方法论功能和教学论功能[1]。笔者在利用教科书中铁的吸氧腐蚀实验[2]进行教学时,如图1,发现该实验仅能让学生体会吸氧腐蚀的吸氧过程,而更核心的电化学过程却无法感受到。通过查阅近年文献,发现同仁们对该实验的研究更多关注如何缩短实验所用时间[3-6]。即便     

基于环糊精的新材料的研究进展

从纳米粒子、水凝胶、纤维材料和环糊精高分子等方面介绍了近年来以环糊精为基础研制的新材料的研究进展。目前以环糊精为基础的纳米粒子材料有核壳结构的纳米粒子、环糊精的化学接枝与共聚、环糊精与无机非金属材料的复合和含环糊精的囊泡材料;以环糊精为基础的凝胶材料有水凝胶和有机凝胶两种材料;此外还有以环糊精为基础的纤维材料、环糊精高...     

某些助剂对明胶的凝胶强度的影响的研究

众所周知,物理力学性能是照相明胶的一种很重要的属性。在各种彩色及黑白胶片都面向高温快速加工发展的今天,这种属性就显得更为重要。提高胶片的物理力学性能,一方面要从提高明胶本身的胶冻强度着手,例如减少明胶中溶胶组份(分子量小、冷水中溶解度高),提高明胶中的α和β组份的相对含量,减少分子量过大的组份等等。     

基于钯催化的Catellani反应的Rhazinal的高效全合成

Rhazinal是Rhazinilam家族中的一员,其家族都含有一个因环张力而形成的吡咯-苯胺手性轴,一个高张力的九元内酰胺,一个全碳季碳手性中心以及[3.4]并环结构.Rhazinilam被发现是一个很好的多种癌细胞的抑制剂,具有诱导和促进微管蛋白的聚合、防止解聚、稳定微管的作用.自其被分离之后得到了有机和生物有机化学家的广泛重视,至今已有多个其家族成员的全合成的报道.中国科学技术大学化学系顾振华小组将Pd催化的Catellani反应首次成     

丙烷分子的价轨道(2b2)电子的动量分布测量

电子动量谱学（EMS）是在原子、分子和固体物理中研究电子结构的一种强有力的工具，它基于运动学条件完全确定的（e，2e）碰撞电离反应[1-3]．本文报告用高分辨电子动量谱仪首次测量得到丙烷门3H8）分子的价轨道电子（252）的动量分布·丙烷（C3Hs）价轨道电子的动量分布实验是     

Electron Momentum Spectroscopy of Ethanethiol Complete Valence Shell

The binding energy spectra and electron momentum distributions for the complete valence orbitals of ethanethiol were measured for the first time by binary (e, 2e) electron momentum spectroscopy employing non-coplanar symmetric kinematics at an impact energy of 1200 eV plus binding energy. The experimental results are generally consistent with the theoretical calculations using density functional theory and Hartree-Fock methods with various basis sets. A possible satellite line at 17.8 eV in binding energy spectrum was observed and studied by electron momentum spectroscopy.     

环戊烷分子的电子动量谱

报导了在高分辨率电子动量谱仪上获得的环戊烷分子的结合能谱和动量谱的实验结果,并用Hartree-Fock方法和密度泛函方法做了理论计算.实验得到的环戊烷分子各电子轨道的电离能值与光电子谱得到的数据一致,动量分布的实验结果也与理论计算基本吻合.     

环己烯分子2b和3a轨道的电子动量谱学研究

The electron momentum profile for inner valence orbitals 2b and 3a of cyclohexene (C6H10) was firstly studied by the binary (e,2e) electron momentum spectroscopy (EMS), at the impact energy of 1200 eV plus binding energy using symmetric non-coplanar kinematics. The complete valence shell binding energy spectrum of C6H10 was also obtained. The experimental momentum profile of the summed orbitals was compared with Hartree Fock (HF) and density functional theory (DFT) methods with various basis sets. The experimental measurement was well described by the HF and DFT calculations except for the low-p region (p<0.25 a.u.). Experimental small “turn-up” effects of momentum profile in the low-p region could be due to the distorted wave effects.     

An investigation of valence shell orbital momentum profiles of difluoromethane by binary (e,2e) spectroscopy

The electron binding energy spectra and momentum profiles of the valence orbitals of difluoromethane, also known as HFC32 (HFC-hydrofluorocarbon) (CH(2)F(2)), have been studied by using a high resolution (e,2e) electron momentum spectrometer, at an impact energy of 1200 eV plus the binding energy, and by using symmetric noncoplanar kinematics. The experimental momentum profiles of the outer valence orbitals and 4a(1) inner valence orbital are compared with the theoretical momentum distributions calculated using Hartree-Fock and density functional theory (DFT) methods with various basis sets. In general, the shapes of the experimental momentum distributions are well described by both the Hartree-Fock and DFT calculations when large and diffuse basis sets are used. However, the result also shows that it is hard to choose the different calculations for some orbitals, including the methods and the size of the basis sets employed. The pole strength of the ionization peak from the 4a(1) inner valence orbital is estimated.     

Electron momentum spectroscopy of CF2Cl2: experimental and theoretical momentum profiles for outer valence orbitals

Electron momentum distributions for outer valence orbitals of CF2Cl2 have been obtained by (e,2e) electron momentum spectroscopy at an incident energy of 1200 eV + binding energy. The experimental electron momentum profiles are compared with Hartree-Fock and density functional theory (DFT) calculations using B3LYP hybrid functional with the 6-31G and 6-311+G* basis sets. Generally, the shapes of the experimental momentum profiles are well reproduced by DFT calculations using larger basis sets 6-311 + G*. An attempt has been made to clarify the ordering of the outer valence orbitals, which have been in controversy, by comparing experimental results with B3LYP/6-311 + G* calculations.     

The outer valance orbital electron densities of cyclopentane by binary (e,2e) spectroscopy

The binding energy spectra and electron distributions in momentum space of the valence orbitals of cyclopentane (C(5)H(10)) are studied by Electron Momentum Spectroscopy (EMS) in a noncoplanar symmetric geometry. The impact energy was 1200 eV plus binding energy and energy resolution of the EMS spectrometer was 1.2 eV. The experimental momentum profiles of the outer valence orbitals are compared with the theoretical momentum distributions calculated using Hartree-Fock and density functional theory (DFT) methods. The shapes of the experimental momentum distributions are generally quite well described by both the Hartree-Fock and DFT calculations when the large and diffuse basis sets are used.     

High resolution electron momentum spectroscopy of the valence orbitals of water

The development of a third-generation electron momentum spectrometer with significantly improved energy and momentum resolutions at Tsinghua University (ΔE = 0.45–0.68 eV, Δθ = ±0.53° and Δ? = ±0.84°) has enabled a reinvestigation of the valence orbital electron momentum distributions of H₂O with improved statistical accuracy. The measurements have been conducted at impact energies of 1200 eV and 2400 eV in order to check the validity of the plane wave impulse approximation. The obtained ionization spectra and electron momentum distributions have been compared with the results of computations carried out with Hartree Fock [HF] theory, density functional theory in conjunction with the standard B3LYP functional, one-particle Green’s function [1p-GF] theory along with the third-order algebraic diagrammatic construction scheme [ADC(3)], symmetry adapted cluster configuration interaction [SAC-CI] theory, and a variety of multi-reference [MR-SDCI, MR-RSPT2, MR-RSPT3] theories. The influence of the basis set on the computed momentum distributions has been investigated further, using a variety of basis sets ranging from 6-31G to the almost complete d-aug-cc-pV6Z basis set. A main issue in the present work pertains to a shake-up band of very weak intensity at 27.1 eV, of which the related momentum distribution was analyzed for the first time. The experimental evidences and the most thorough theoretical calculations demonstrate that this band borrows its ionization intensity from the 2a₁ orbital.     

异丁烷分子的电子动量谱

电子动量谱学自本世纪六十年代［１］以来,已发展成为探测原子分子的电子结构的强有力工具．借助电子动量谱学可获得精确的分子轨道电子密度分布,并能提供非常详细的电子运动和电子关联信息．有关这方面的理论和实验技术的详细综述可参考文献［２］．到目前为止,运用光电子谱学方法,已对饱和烷烃的价壳层结合能谱进行了广泛的研究［３］,但是用（ｅ,２ｅ）技术仅测量了甲烷［４,５］、乙烷［６］、丙烷［７］、丁烷［８］的价轨道电子动量分布．本文简要报导利用高分辨率（ｅ,２ｅ）谱仪获得的异丁烷分子的结合能谱和动量分布的实验…     

CF2BrCl分子近域轨道的电子动量谱学研究

The frontier molecular orbitals (HOMO and NHOMO) of CF2BrCl molecule have been firstly investigated by (e,2e) electron momentum spectroscopy. The experimental momentum profiles are compared with the theoretical profiles employing Hartree-Fock and density functional theory with 6-31G and 6-311+G(d) basis sets. Both HF and DFT calculations using 6-311+G(d) basis set can well describe the experiment, whereas those calculated using 6-31G basis set largely underestimate the experiment at the low momentum region. Furthermore, orbital electron density images show that HOMO and NHOMO have a mixed character of the bromine and chlorine lone pairs.