衍生顶空气相色谱法测定饮用水源水中的三氯乙醛

采用衍生顶空气相色谱法测定饮用水源水中的三氯乙醛。通过加碱将三氯乙醛转化成氯仿,采用微电子捕获检测器(μECD)进行检测,优化了顶空色谱条件。三氯甲醛的浓度在1.0～20.0μg/L范围内与色谱峰面积呈良好的线性关系,相关系数r=0.9994。对2.0μg/L标准溶液重复测定6次,测定结果的相对标准偏差为4.1%,方法的检出限为0.10μg/L。实际水样平均加标回收率为97%。该方法满足GB3838-2002的要求。     

猪肝中克伦特罗和沙丁胺醇的毛细管电泳-质谱联用分析

盐酸克仑特罗和沙丁胺醇等均属激动剂类药物,人体的累计摄入量超过一定值或食用了高残留的内脏组织,易出现毒副作用[1],因此许多国家都将其列为违禁药物。近年来一些不法饲养业主受利益驱使,将沙丁胺醇(salbutamol)作为“瘦肉精”的替代品在生猪养殖中非法使用。关于克伦特罗和     

气相中Y＋, Zr＋, Nb＋与CO2反应的理论研究

以Y^＋, Zr^＋, Nb^＋与CO₂反应作为第二前过渡金属离子与CO₂反应的范例体系. 采用密度泛函UB3LYP方法, 对于Y, Zr, Nb采用Stuttgart赝势基组, 对于CO₂采用6-311＋G(2d)基组, 计算研究了三种金属离子在基态和激发态时与CO₂气相反应的机理. 结果表明三种金属离子与CO₂反应以高自旋进入反应通道, 在反应过程中发生系间窜越, 以低自旋中间体和最终产物离开反应通道. 用内禀坐标单点垂直激发计算的方法找到了势能面交叉点, 并作了相应的讨论. 因为有金属离子的参与, 使单分子CO₂的强吸热分解反应变为生成CO和MO^＋的放热过程.     

溶液中变性剂浓度对蛋白溶菌酶复性的影响

Based on three-state renaturation process of denatured proteins, an equation describing the effect of denaturant concentration on renaturation yield of denatured proteins was presented. By this equation, two parameters n（m1 -m2） and Ka can be obtained. The former indicates the difference in the number of denaturant molecules between the renaturation process of n number of refolding intermediates from refolding intermediate state to native state and their aggregate process from refolding intermediate state to aggregate state, the latter denotes the apparent aggregate equilibrium constant for protein molecules aggregated from native state to aggregate state, and from them, the characteristics of the renaturation process of denatured proteins in denaturant solution can be identified. This equation was tested by the renaturation processes of denatured egg white lysozyme in guanidine hydrochloride and urea solutions, with the results to show that when guanidine hydrochloride and urea concentrations were separately higher than 1.25 and 3.00 mol/L or separately lower than 1.00 and 3.00 mol/L, the refolding intermediates of egg white lysozymes were more easily aggregated to aggregate state or more easily renatured to native state, respectively. Under different initial total egg white lysozyme concentrations in urea solution, the refolding egg white lysozyme intermediates could be deduced to have a tendency to form a bimolecular intermediate aggregate, and this inference was further confirmed by their nonreducing SDS-PAGE and size exclusion chromatography.     

A Simple Frontal Analysis Equation to Determine the Adsorption Parameters of Solute Molecules on Different Adsorbents

A simple frontal analysis equation to determine the adsorption parameters of solute molecules on different adsorbents was presented. It gives the relationship between the average breakthrough time and the feed solute concentration, and by using its linear form, two important parameters, the thermodynamic equilibrium constant KSL for solute adsorption on the surface of adsorbent and the number nt of total adsorption sites distributed on the surface of adsorbent, can be simultaneously determined. The frontal analyses for some aromatic hydrocarbons on RP-C18 reversed-phase medium, and some protein molecules on RP-C18 reversed-phase, WCX-1 cation-exchange, PEG-400 hydrophobic and Chelating Sepharose Fast-flow separately chelated with Zn^2＋ or Cu^2＋ media, were separately carried out to test this equation and their adsorption parameters KSL and nt were separately obtained. The results show that all these frontal analysis data can be well described by this frontal analysis equation. For all of these frontal analysis systems, their parameters nt can separately approximately keep constant and they are independent of solute molecules used, while their parameters KSL are dependent upon both of the media packed in frontal analysis column and the solute molecules used.     

一些层状纳米复合材料的制备和应用

无机层状化合物因其层间离子的可交换性而受到人们广泛的关注,通过功能性客体分子的插层,所得层状纳米复合材料具有独特的物理与化学性质,在催化、医药、电化学和生物传感、离子交换和吸附以及光学等方面具有广泛而重要的应用,已成为当前材料研究领域中的前沿和热点。本文主要综述了近年来有关层状纳米复合材料的制备和应用的最新研究进展。     

卡式系统装调对高功率激光光束远场聚焦性能影响研究

以广义惠更斯-菲涅尔衍射理论为基础,采用Zernike多项式描述像差光束畸变波前相位,研究超高斯光束因卡式系统加工和装调导致波像差劣化后,通过传输在远场聚焦性能。分析主次镜系统波像差下降到1/13λ左右时,对应像散和慧差对聚焦位置处光强分布和光斑桶中功率PIB影响。结果表明:相对理想系统,像差会导致聚焦位置处光束展宽,80%处桶中功率PIB下降明显,但对应95%能量范围光斑直径在设计值允许范围内,仍然满足总体使用要求。     

大视场空间对地遥感卡塞格林光学系统设计

设计了用于空间对地遥感的卡塞格林光学系统,系统的焦距为1000mm,F=5．6,光谱范围0．4～O．9μm,视场为3°,畸变小于1％。采用CODEV软件优化出两种系统结构形式,这两种结构形式的光学传递函数都接近衍射极限。将第二种形式的主镜的抛物面改成双曲面,并在校正组中引入了两个高次非球面,校正透镜组减少了两片透镜,其结构简单、体积小、重量轻,更适用于空间遥感应用环境。     

弱投射维数

引入了弱投射模及弱投射维数的概念,说明弱投射模是FP-投射模的真子类.给出了环的整体弱投射维数的刻画,并得到了凝聚环和Noether的一些新的同调刻画.     

水平管气力输送最佳经济速度的模拟研究

本文建立了三维水平圆管的输送的简化数学模型,运用流体力学软件FLUENT对不同输送浓度的颗粒在水平管中输送的流动情况进行数值模拟.对不同输送工况下的压降损失与气体速度的关系进行了对比分析,并确定了在特定条件下能耗最小的经济速度并与实验数据进行了对比.结果表明计算结果与实验数据基本吻合,用于FLUETNT模拟计算的简化数学模型具有较好的适应性和准确性,研究结果对工程应用具有一定的指导意义.