成云过程中云水pH值的参数化

该文找出了影响云水ｐＨ值的主要因素，用统计分析的方法得到它们与云水ｐＨ值之间的简单的函数关系。通过参数化研究发现，在一定的变量取值范围内，模式模拟的结果与用函数关系式得到的结果能很好地对应起来，相关系数为０９４。该文参数化所考虑的变量为：气相Ｈ２Ｏ２，Ｏ３，ＳＯ２与ＮＨ３的浓度，液相Ｆｅ３＋与Ｍｎ２＋的浓度，水的含量及温度。

光纤pH传感器

本文叙述了一种在光纤端面放置固定化pH染料指示剂的反射式光纤传感器,其探头结构是通过共价结合法把酚红、溴酚兰和百里酚兰等三种染料固定在丙烯酰胺微球上形成亲水凝胶状指示剂,用聚四氟乙烯网膜定位放置,同光纤端面间留有一定缝隙,便于指示剂与被测溶液的离子交换,反应。文中给出这种光纤传感器的全部性能参数,其测试范围3.0—5.0pH(溴酚兰指示剂);7.0—8.5pH(酚红指示剂)和8.0—10.0pH(百里酚兰指示剂);灵敏度66.6mV/pH;精度优于0.05pH;相关系数达99.9％;重复性0.013mV;响应时间(90％)对酚红指示剂为2min,对百里酚兰1min;滞后为0.52％;稳定性为0.015pH/h,该器件性能优良、制造简单,具有实用价值。

Estimation of Aggregate Losses of Secondary Cancer Using PH-OPPL and PH-TPPL Distributions

Kenyan insurance firms have introduced insurance policies of chronic illnesses like cancer; however, they have faced a huge challenge in the pricing of these policies as cancer can transit into different stages, which consequently leads to variation in the cost of treatment. This has made the estimation of aggregate losses of diseases which have multiple stages of transitions such as cancer, an area of interest of many insurance firms. Mixture phase type distributions can be used to solve this setback as they can in-cooperate the transition in the estimation of claim frequency while also in-cooperating the heterogeneity aspect of claim data. In this paper, we estimate the aggregate losses of secondary cancer cases in Kenya using mixture phase type Poisson Lindley distributions. Phase type (PH) distributions for one and two parameter Poisson Lindley are developed as well their compound distributions. The matrix parameters of the PH distributions are estimated using continuous Chapman Kolmogorov equations as the disease process of cancer is continuous while severity is modeled using Pareto, Generalized Pareto and Weibull distributions. This study shows that aggregate losses for Kenyan data are best estimated using PH-OPPL-Weibull model in the case of PH-OPPL distribution models and PH-TPPL-Generalized Pareto model in the case of PH-TPPL distribution models. Comparing the two best models, PH-OPPL-Weibull model provided the best fit for secondary cancer cases in Kenya. This model is also recommended for different diseases which are dynamic in nature like cancer.

基于约束Jacobi基的多项式反函数逼近及应用

求解多项式反函数是CAGD中的一个基本问题.提出一种带端点Ck约束的反函数逼近算法.利用约束Jacobi基作为有效工具,推导了它与Bernstein基的转换公式,采用Bernstein多项式的升阶、乘积、积分与组合运算,给出了求解反函数系数的具体算法.该算法稳定、简易,克服了以往计算反函数的系数时每次逼近系数需全部重新计算的缺陷.最后通过具体逼近实例验证了文中算法的正确性和有效性,同时给出了它在PH曲线准弧长参数化中的应用.