测定氨氮时浓度及时间对反应的影响

采用纳氏试剂分光光度法，对不同浓度的氨氮标准溶液在各显色时间下的吸光值进行了分析，以了解实验随浓度、时间的变化情况，掌握达到最大显色所需的时间。从而指导实际的检测工作。     

一个有界弹性项Duffing方程周期解的存在性

证明了有界弹性项Duffing方程x″ arccotx=p(t)的周期解的存在性,其中周期为2π的连续函数p(t)满足0     

10-对硝基苯氧基癸酸合成工艺的改进

对10-对硝基苯氧基癸酸合成工艺进行了改进.以10-溴代癸酸为原料,与甲醇反应生成10-溴代癸酸甲酯,再与对硝基酚钠反应生成10-对硝基苯氧基癸酸甲酯,最后以固定化脂肪酶水解得到10-对硝基苯氧基癸酸.对中间体的折光率和紫外-可见光谱进行分析,并通过紫外-可见光谱1、H-NMR和13C-NMR以及酶分析应用对最终产物进行确证.结果表明,成功合成出目标化合物,总收率达到71.6%.     

具有非凸条件的单个守恒律初边值问题整体弱熵解的结构

在流函数具有有限个拐点,初始值为两段常数和边界值为常数的条件下,研究非凸单个守恒律的初边值问题整体弱熵解的结构、初等波与边界的相互作用情况以及弱熵解在边界附近的性态.     

与年龄相关的非线性时变种群系统的L2(Q)-解

本文讨论与年龄相关的非线性时变种群系统（P）的l^2（Q）－解，为进一步研究种群系统的最优控制问题提供了必要的理论基础．     

Preface

Different from traditional tax audit, supervision with self-audit is a combination of audit by the taxpayer himself and audit by the tax authority. This paper mainly studies a taxpayer’s optimal policy of tax evasion under supervision with self-audit and its related properties, in order to deduce some effective suggestions and theoretical bases to restrain tax evasion. Assuming that only a certain proportion of evaded tax can be discovered when the audit is executed, the authors first formulate a static model with self-audit. This model is divided into two stages. At the first stage, taxpayers declare their taxes, then the tax authority chooses audit objects, based on a known probability, and announces the result; if the taxpayer is chosen, he will enter the second stage, during which he has a chance to pay the evaded tax and the corresponding late fees and then is audited by the tax authority. The authors show the existence and uniqueness of the optimal amount of tax evasion at the first stage and the optimal proportion to self-expose at the second stage. The authors also discuss the related properties of the interior solution, and do elasticity analyses on some parameters. Besides, the authors extend the static model into the corresponding two-period model, and study the existence and uniqueness of the solution of the extended model. Finally, under the assumption that tax evasion can only be discovered with a certain probability when the audit is executed, the authors formulate another static model with self-audit and investigate its properties. This research is partially supported by the National Natural Science Foundation of China under Grant Nos. 60674082, 70221001, and 70731003.     

水合硫酸铁在丙烯酸酯化反应中的催化作用

研究了用水合硫酸铁替代硫酸作催化剂，催化丙烯酸与多种醇的酯化反应，发现其具有良好的催化活性．探讨了醇的结构对催化剂和酯化反应的影响，以及催化酯化反应的可能机理     

硒化蓖麻酸多相脂质体抗癌机理研究

本文用小角ｘ射线射法法对硒化蓖麻酸多相脂质体的抗癌作用从结构和功能上进行了研究。     

论内含报酬率的几何解法

<正> 内含报酬率,又称内部报酬率,是指能使投资项目的预期现金流入量现值等于预期现金流出量现值的贴现率,即能使投资项目的净现值为零的贴现率。内含报酬率常可用于分析评价投资项目的可行性,以便进行投资决策。对于单一的投资方案,当内含报酬率高于企业的资金成本率时,可以考     

奇摄动非线性微分方程周期边值问题解的估计

本文考虑一类二阶非线性微分方程奇摄动周期边值问题。利用微分不等式技巧,不仅研究了解的存在性,而且还给出解及其导数的估计,从而提供了研究解的导数估计的一种方法。