掺杂剂对聚乙炔性质影响的理论研究

以多烯烃模拟聚乙炔链,用CNDO/2方法讨论了各种掺杂剂对聚乙炔性质的影响,掺杂剂使孤子宽度收缩变窄,且p型掺杂剂比n型掺杂剂的影响更大,掺杂剂影响聚乙炔链中的电荷密度波,使电荷主要集中分布于掺杂剂附近的碳原子上。掺杂碱金属时,掺杂剂原子的最高占据轨道与聚乙炔中孤子自旋轨道之间的作用由Li到K依次增强,解释了ESR实验结果。     

小环化合物中饱和碳质子化学位移的计算

小环化合物由于其张力、构型、构象和各向异性效应等原因,环碳上质子化学位移缺乏规律性,难以预测,对此作者曾提出一种近似算法。本文根据303种小环化合物中饱和碳质子的化学位移实验数据,将适于计算这类质子化学位移的公式表述为:     

新极谱法中重叠峰的分辨

依据新极谱信号线性迭加原理,采用标准加入法和多元线性回归,提出了新极谱法中重叠峰多元线性回归分辨方法,可以将重叠峰分辨开来,同时可求得产生重叠峰的2个组分的浓度.方法原理简明,计算速度快,具有较高的准确度和极强的分辨能力.应用于In(Ⅲ)-Cd(Ⅱ)和Pb(Ⅱ)一T1(Ⅰ)体系的阶梯扫描新极谱法测定,取得较为满意的结果。     

臭氧化物生成机理研究综述

以Criegee三步反应机理为核心对烯烃臭氧化反应中的臭氧化物生成机理进行了综述。论述了初级臭氧化物的生成与分解和臭氧化物生成过程的选择性和立体化学。讨论了烯烃结构和反应各步骤的选择性和立体化学的关系。     

聚氨酯改性不饱和聚酯树脂的反应动力学

通过差示扫描量热法(DSC)和傅里叶红外光谱(FT-IR)分析,探讨了聚氨酯改性不饱和聚酯树脂(UPR)体系反应特征及固化反应动力学。结果表明:体系中聚氨酯网络的形成远快于UPR网络的形成。UPR和聚氨酯改性UPR体系的表观活化能分别为58.0 kJ/mol和64.8 kJ/mol,改性后体系的活化能并无较大变化;反应的级数分别为0.90和0.91。     

Research of Natural Frequency of Single-walled Carbon Nanotube

The modied molecular structural mechanics method (MMSMM) is extended to analyze the dynamic characteristics of single-walled carbon nanotubes (SWCNTs). In MMSMM, the deformation potential of SWCNT is decomposed and it can be easily expressed as the function of the positions of carbon atoms in molecular mechanics, and so the sti?ness matrix of SWCNT can be obtained. The elemental mass matrix is a diagonal one, so the natural frequency and vibration mode of SWCNT can be calculated e?ectively. In this work, the form of cantilevered nanotubes is analyzed. The natural frequencies of SWCNT computed by this algorithm are discussed. The frequency dependence on the tube diameter and length of SWCNT is conˉrmed and, it is shown that when the diameter of tube is small the frequency can reach the the GHz level. The frequency results and the vibration modes are comparable with those of other researchers. Furthermore, a new FEM continuum-model is proposed to analyze the dynamic character of SWCNT to compare with these results by MMSMM.     

稀酸溶液中氯离子对工业纯铁的腐蚀机理研究

关于铁在酸性溶液中的腐蚀电化学行为，对不合特性吸附离子的体系而言，溶液PH值的改变对铁的阳极溶解起着重要作用，表明0＊一参与了钱的阳极溶解过程k’］．当向体系中引入具有特性吸附能力的执离子时，可以引起腐蚀中铁的腐蚀电位、Tdel斜率以及腐蚀电流密度和反应级教等诸多数的变化问，表明CI一也参与了铁腐蚀的电化学过程问．由于介质体系、电板材料及实验条件的差异，不同的研究者所获得的实验结果也不同卜和．然而，这些机理所讨论的均为把高于对阳极过程的影响，对氛离子存在时是否影响阴极析氢过程较少有实验证明．并且，对阳极…     

植物甾醇女士访谈录

通过采访植物甾醇女士,了解植物甾醇家族的成员、基本性质、生理功能等。揭示了其降低胆固醇、减肥、美容功能的基本原理,了解了抗癌机理,介绍了植物甾醇在食物中的分布、人体吸收困难的原因及对策,为人类健康生活提出膳食建议。     

An expedient synthesis of the repeating unit of the acidic polysaccharide of the bacteriolytic complex of lysoamidase

The first synthesis of the trisaccharide repeating unit of the acidic polysaccharide of the bacteriolytic complex of lysoamidase is presented. The construction is based on a linear glycosylation strategy that starts from the reducing end and employs thio- and selenoglycosides in a highly stereoselective manner by a single set of activation conditions. The thus-formed trisaccharide is selectively deprotected and oxidised, after which a final deprotection step furnishes the desired repeating unit.     

生物油部分氧化气化制备合成气研究

以生物油为原料,在常压和空气氛围下进行非催化部分氧化气化实验制备合成气,考察了气化温度、氧油比对合成气形成特性及合成气品质的影响,并对生物油非催化部分氧化气化制备合成气的主要反应过程进行了讨论。结果表明,升高温度可以促进生物油经非催化部分氧化气化制合成气过程中相关转化反应的进行,合适的氧油比有利于合成气的增加。当温度为1 050℃,空气量为0.2 L/min,进料量为72 g/h时,生物油经部分氧化产生的气体中H₂含量最高,CH₄、CO和CO₂很少;H₂/CO和H₂/(CO+CO₂)均达到最大值,分别为4.3和3.2。     

Effect of form of reagent on particle sizes of precipitates

The particle size of an ionic precipitate is much smaller when one of the reactants is introduced as a solid rather than as a solution The effect is enhanced as the particle size of the solid reagent is decreased. The presence of a freshly dissolved inert electrolyte also influences the particle size of a precipitate The affects are not attributable merely to the degree of supersaturation but rather to the provision by the freshly dissolved material of sites upon which nucleation can be induced.     

Ab initio Study of Electronic Structure and Properties of Crystalline of 1,5-Diamino-1,2,3,4-tetrazole

Density functional method was applied to study 1,5‐diamino‐1,2,3,4‐tetrazole (DAT, CH₄N₆) in both gaseous and bulk states. The banding and electronic structures of crystalline have been investigated at DFT‐B3LYP/ 6‐311G** level of theory. Relaxed crystal structure compares well with experimental data. The light fluctuation of the frontier orbital, which is mainly formed by atomic orbital of N(4) (heterocycle), is the most reactive part of the molecule, which is in good agreement with the experimental results. The energy gap is 9.035 eV, which indicates that DAT is an insulator. The distribution of electrostatic potential is uniform, indicating DAT is insensitive. The charge density of the intermolecular regions in the plane is not overlaid, indicating that the intermolecular interaction between the neighboring molecules along this direction in the bulk is very weak. The overlap populations of N(1)? N(2) bonds are much less than those of other bonds, therefore the N(1)? N(2) bonds first rupture by external stimuli.     

Spectrophotometric Catalytic Determination of Trace Amounts of Selenium Based on the Reduction of Azurea by Sulphide

ABSTRACT

A sensitive catalytic kinetic spectrophotometric method for determining ng ml^?1 concentrations of selenium is described. The method, based on the catalytic effect of Se (IV) on the reduction of azureA by sulphide, is monitored spectrophotometrically at 600 nm. The linearity range of the calibration graph is dependent on the concentration of sulphide. The variables affecting the rate of the reaction were investigated and the optimum conditions were established. The method is simple, rapid, precise, sensitive, free from many interferences and is widely applicable. The limit of detection is 2.5ng ml^?1 of Se. The relative standard deviation of seven determinations of 100 ng ml^?1 Se was 1.5%. The method was applied to the determination of selenium in spiked water, Kjeldahl tablets, synthetic samples and health care products.     

柴油对流动改进剂感受性差异的原因表征与分析

柴油对低温流动改进剂具有较高的选择性。流动改进剂对不同的炼油厂、不同原油以及不同的加工工艺炼制的柴油的感受性和降冷滤效果截然不同。主要是由柴油的化学组成决定。一般认为，柴油中正构烷烃的摩尔分数和分布是影响其低温流动改进剂使用效果的主要因素。正构烷烃摩尔分数越低，碳数分布越广，添加低温流动改进剂效果越好；此外，柴油中所含的单环芳烃是高碳数烷烃的优良溶剂，其摩尔分数越高，柴油低温蜡析出量越少，加低温流动改进剂效果越好。     

铝土矿有效铝含量测定影响因素研究

研究了影响铝土矿中有效铝含量测定的主要影响因素。主要探讨了样品粒度、均匀性对有效铝溶出效果的影响及样品组成对有效铝含量大小的影响。利用电感耦合等离子体原子发射光谱(ICP-AES)法测定铝土矿中有效铝含量、X射线荧光光谱(XRF)法测定铝土矿中总氧化铝含量和其它杂质成分含量,借助X射线衍射光谱(XRD)法对样品进行物相组成分析,确定各主要组成的结构和占比。将样品制备至0.106mm以下,均匀性好,精密度高,有效铝溶出率高。样品物相组成中三水铝石占比高,一水铝石占比低,与氢氧化钠低温条件更易反应,使溶出率高。通过加标回收实验验证方法的加标回收率为99.1%～101%,实验标准偏差为0.14%,相对标准偏差为0.003%,可对铝土矿有效铝的监控提供技术支撑。     

Startup of electrophoresis in a suspension of colloidal spheres

The transient electrophoretic response of a homogeneous suspension of spherical particles to the step application of an electric field is analyzed. The electric double layer encompassing each particle is assumed to be thin but finite, and the effect of dynamic electroosmosis within it is incorporated. The momentum equation for the fluid outside the double layers is solved through the use of a unit cell model. Closed‐form formulas for the time‐evolving electrophoretic and settling velocities of the particles in the Laplace transform are obtained in terms of the electrokinetic radius, relative mass density, and volume fraction of the particles. The time scale for the development of electrophoresis and sedimentation is significantly smaller for a suspension with a higher particle volume fraction or a smaller particle‐to‐fluid density ratio, and the electrophoretic mobility at any instant increases with an increase in the electrokinetic particle radius. The transient electrophoretic mobility is a decreasing function of the particle volume fraction if the particle‐to‐fluid density ratio is relatively small, but it may increase with an increase in the particle volume fraction if this density ratio is relatively large. The particle interaction effect in a suspension on the transient electrophoresis is much weaker than that on the transient sedimentation of the particles.     

Improved method of sampling and determination of traces of hydrogen sulphide

A sensitive spectrophotometric method for the determination of traces of hydrogen sulphide in environmental samples, after fixation as zinc sulphide, is reported. The method is based on the reaction between iodate and sulphide in the presence of excess of chloride ions. The resulting iodine chloride complex is ion-paired with Pyronine G and the product is extracted into benzene. The colour system obeys Beer's law over the range of 0.05–0.6 g of hydrogen sulphide. The coefficient of variation is 6.3% for 10 determinations of 0.3 g of hydrogen sulphide. The suitability of the method for monitoring hydrogen sulphide in atmospheric air in the vicinity of possible sources such as a sewage treatment plant and in wastewater has been evaluated.     

HALS和抗氧剂对PE辐射致色的影响

聚乙烯;稳定剂;HALS和抗氧剂对PE辐射致色的影响     

工业污泥中铜含量的不同测定方法对比

采用火焰原子吸收分光光度法（AAS）和快速碘量法对工业污泥中铜含量进行测定,并对结果做了对比分析.结果表明两种方法的准确性和可操作性均较好,回收率在91.0%~99.0%之间,相对标准偏差均低于7%.碘量法分析简单,结果准确可靠,但不适合分析大批量的样品.火焰原子吸收分光光度法分析速度较快,灵敏度高,可以同时进行大批量的样品分析.     

聚(4-乙烯基吡啶季铵盐-丙烯酰胺)的抗菌性能与机理研究

季铵盐型阳离子聚合物具有絮凝、缓蚀与杀菌等多种功能,据此,我们通过分子设计,先将丙烯酰胺与4-乙烯基吡啶（4-VP）进行共聚合,然后使用季铵化试剂硫酸二甲酯使共聚物阳离子化,制备了吡啶季铵盐型阳离子聚丙烯酰胺（QPAV）,本文报道QPAV的抗菌性能,并探讨其抗菌机理,结果表明,吡啶季铵盐型阳离子聚丙烯酰胺具有很强的抗菌性能,且其抗菌机理是基于杀菌而不仅仅是抑菌。