表面活性剂增敏催化光度法测定痕量亚硝酸根

基于在稀硫酸介质中溴代十六烷基吡啶 (CPB)对亚硝酸根 (NO-2 )催化溴酸钾氧化碘曙红褪色反应的增敏作用 ,建立了测定NO-2 的表面活性剂增敏催化动力学光度法 .由于加入增敏剂 ,灵敏度显著提同 .lgA0 /A值与NO-2 含量在 0～ 1.0 μg/mL范围内存在线性关系 ,检出限量为0 .0 6 μg/ml.方法用于水样、蔬菜中痕量亚硝酸根的测定 ,结果较好     

视网膜色素上皮DNA蓝光损伤及维生素E的保护作用

目的：探讨维生素E对视网膜色素上皮DNA蓝光损伤的保护作用。方法：视网膜色素上皮细胞分为3组：正常组（不照光），实验组（蓝光照射40min），维生素E组（蓝光照射同时给予维生素E）。采用火箭电泳的方法对各组视网膜色素上皮DNA损伤进行分析。结果：各组火箭电泳尾部DNA含量分别为18．44％，54．42％和22．16％。各组差异有显著性意义（P＜0．01）。结论：蓝光能对视网膜色素上皮的DNA产生损伤，维生素E对损伤能起到一定的保护作用。     

磺化麦草碱木质素热分析动力学研究

为研究磺化碱木质素在高温条件下的热稳定性能，实验采用热重－红外分析(TG-IR)和差示扫描量热分析(DSC) 研究了磺化麦草碱木质素在非氧状态下热分解反应的动力学过程。利用多升温速率法Kissingr法和Ozawa法，分别计算了磺化麦草碱木质素热动力学方程中的表观活化能(Ｅ)和频率因子lnA，分别为118.3 kJ•mol-1、121.46 kJ•mol-1；20.40min-1、15.92min-1；利用Kissingr法计算了热动力学方程的反应级数是1.8。     

Comparison of two methods of estimation of low density lipoprotein cholesterol, the direct versus friedewald estimation

Current recommendations of the Adult Treatment Panel and Adolescents Treatment Panel of National Cholesterol Education Program make the low-density lipoprotein cholesterol (LDL-C) levels in serum the basis of classification and management of hypercholesterolemia. A number of direct homogenous assays based on surfactant/solubility principles have evolved in the recent past. This has made LDL-C estimation less cumbersome than the earlier used methods. Here we compared one of the direct homogenous assays with the widely used Friedewald’s method of estimation of LDL-C to see the differences and correlation. We used direct homogenous assay kit to estimate serum LDL-C and high-density lipoprotein cholesterol (HDL-C). Serum Triglyceride (TG) and Total Cholesterol (TC) was estimated and using Friedewald’s formula LDL-C was calculated. The LDL-C level obtained by both methods in 893 fasting serum samples were compared. The statistical methods used were paired t-test and Pearson’s correlation. There was significant difference in the mean LDL-C levels obtained by the two methods at the TG levels <200 mg/dl (p<0.02) and TC levels >150 mg% (p<0.001). The correlation coefficient (r) between Friedewald’s and direct assay estimation was 0.88. Friedewald’s method classified 23.5 % of patients as high cardiac risk whereas there were 17.58% by direct assay. Both had good correlation even though the serum triglyceride and total cholesterol levels affect the difference in LDL-C estimated by both methods. Taking into account the cost and performance, Friedewald’s method is as good or even better for classifying and managing patients.     

完全弹性碰撞过程中的功、能转换

在物体的完全弹性碰撞过程中，系统内部的功能转换是非常复杂的，一般力学教材对碰撞过程都没有作详细分析。本通过实际举例，对弹性碰撞的全过程作了较详细的分析。     

碱性苦味酸法和酶法测血清肌酐的方法学比较

[目的]了解酶法和碱性苦味酸法测定血清肌酐结果的偏倚大小,对两种方法进行比较.[方法]用生化仪器OLYMPUSAU1000分别进行酶法和碱性苦味酸法测定血清肌酐.对两种方法进行重复性实验、相关性实验、线性比较和回收试验.[结果]酶法和碱性苦味酸法的重复性实验数据(x±s)266±2.77μmol／L和273.5±3.30μmol／L,其变异系数分别为1.04％、1.21％;两者的回归方程式yJaffe=1.01X二步酶法-1.28;酶法的线形范围远大于碱性苦味酸法;在回收试验中两者的回收率分别为98.5％、94.5%.[结论]酶法和苦味酸法有较好的相关性,酶法比碱性苦味酸法线性范围宽,特异性和灵敏度高,测定重复性好,是比较理想的方法.临床上酶法将逐渐代替苦味酸法测定血清肌酐.     

物体的非完全弹性碰撞解析

以动量和动能的计算为前提，通过对非完全弹性碰撞的末速度的求解、恢复系数的测定和动能损失的讨论使得我们对非完全弹性对心正硅有一个既深刘又全面的了解。     

Optimization of a Reduced Chemical Kinetic Model for HCCI Engine Simulations by Micro-Genetic Algorithm

A reduced chemical kinetic model （44 species and 72 reactions） for the homogeneous charge compression ignition （HCCI） combustion of n-heptane was optimized to improve its autoignition predictions under different engine operating conditions. The seven kinetic parameters of the optimized model were determined by using the combination of a micro-genetic algorithm optimization methodology and the SENKIN program of CHEMKIN chemical kinetics software package. The optimization was performed within the range of equivalence ratios 0.2-1.2, initial temperature 310- 375 K and initial pressure 0, 1-0.3 MPa, The engine simulations show that the optimized model agrees better with the detailed chemical kinetic model （544 species and 2 446 reactions） than the original model does.     

Ce（Ⅳ）离子氧化环己酮的反应动力学及机理

在25～40℃范围内用分光光度法研究酸性介质中Ce（Ⅳ）离子氧化环己酮（Re）的动力学机理．结果表明：反应对Ce（Ⅳ）为一级反应,对还原剂环己酮为一级反应;表观速率常数随[H^＋]的增加而增加,随[HSO4^-]的增加而减小;无盐效应;反应中有自由基的存在．据此,提出了Ce（Ⅳ）氧化环己酮的反应机理,能很好地解释全部实验现象,结合反应机理找到了本反应体系的动力学活性物种Ce（SO4）^2＋,并求得30℃时,速控步骤的速率常Kn=3.12mol^-1Lmin^-1.     

半无界区域上热传导方程第三和动力学边界条件的开拓法求解

关于半无界区域上带有第一,第二边界条件的热传导方程,前人已经用开拓法求解出它们的解的一般表达式。但第三边界问题,目前还没有现成的解的表达式;而动力学边界条件,国内外的书籍都甚少涉及。基于此,本论文尝试用开拓法求解第三边界和动力学边界问题的解的表达式。