论在Excel环境下求解IRR指标的必要性

在传统方法下,计算IRR的方法主要有查表法和试误法,查表法由于对数据的一致性要求比较高,因而其适用范围比较窄;而在试误法下,计算非常复杂,若企业所要决策的长期投资项目经济寿命较长,各期的净现金流量的数据就较多,手工计算量非常大,计算结果也不准确。因此,我们有必要引入一种更加科学、准确、快速的方法来计算IRR,以此来评价企业的投资策略的优劣。

丙烯酸-2,4,6-三硝基苯乙酯的合成及热分解

以TNT、甲醛为原料,在弱碱性条件下反应合成得到2,4,6-三硝基苯乙醇(PicCH2CH2OH);PicCH2CH2OH在浓硫酸催化下和丙烯酸在甲苯中回流反应24h,合成得到丙烯酸-2,4,6-三硝基苯乙酯,产率为62%。采用紫外可见光谱(UV-Vis)、核磁共振氢谱(1HNMR)、红外光谱(FTIR)、质谱(MS)以及元素分析等对产物结构进行了表征。利用热重分析(TG)对产物热稳定性进行了研究,采用Kissinger方法和Ozawa方法计算其热分解活化能Ea分别为99.78,102.96kJ·mol-1。

Statistical inference of the lifetime performance index for Lindley distribution under progressive first-failure censoring scheme applied to HPLC data

This paper is devoted to the construct of the maximum likelihood estimator of the life-time performance index based on first-failure progressive right type censored sample for Lindley distribution. Statistical inference for assessing the lifetime performance of the items is performed. Finally, two examples are given, one of them considers a real life application of blood samples from organ transplant recipient using the liquid chromatography （HPLC） data and the other is a simulated example to illustrate the proposed statistical procedure.