化学工程学研究进展与展望

化学工程学经过多年的发展,现已形成一个体系完整、研究内容丰富、研究方法先进的工程技术学科。在新的世纪,伴随着化学工程学科的发展,化学工业将会给人类创造出更多的物质财富,对社会作出更大贡献。     

完整PbWO4晶体偏振性质的模拟计算

利用完全势缀加平面波局域密度泛函近似，计算了完整的PbWO4(PWO)晶体的电子结构，模拟计算了复数折射率、介电函数及吸收光谱的偏振特性．分析了各个吸收光谱的峰值所对应的可能的电子跃迁以及PWO晶体的偏振特性．     

Asymptotic properties of the maximum-likelihood estimator for a class of birth-and-death processes admitting a unique stationary distribution

The asymptotic properties of the maximum-likelihood estimator of the parameter vector for a class of birth-and-death processes admitting a unique stationary distribution are studied. Also, it is shown that identifiability of the parameter vector with respect to the likelihood implies that the Fisher information matrix is of full rank. Two special cases of biological interest are presented. One of these, the exponential birth-and-death process, is proposed as a more appropriate model of density dependence than the logistic process.     

Credibility, Information Preferences, and Information Interests

The Seveso Directive of the European Union demands that information be provided to the public by companies and authorities about facts, risks, and behaviors related to hazardous facilities, in particular chemical facilities. On behalf of the Commission of the European Communities, a survey was run in five European countries on the credibility of various information sources. This article describes the results of the German study. 430 persons were interviewed with a questionnaire of 50 items, in particular about their perceptions and evaluations of technical risks, the credibility of sources of information about chemical risks, their preferences for receiving risk information from these sources, and their interests in receiving information. Major findings are great differences in credibility, differentiated information preferences, and strong information interests. Surprisingly, credibility played only a minor role with regard to the respondents'information preferences and interests.     

灾时危化品事故危机信息管理体系及其运行机制研究

灾害引致的危化品事故危机管理是一个多环节、多变量的复杂工程,其重要进程是对事故危机信息的管理。而要有效实现对灾时危化品事故的危机信息管理,必须建立科学的运行机制。文章运用系统性演绎分析方法。通过对危化品事故的灾时成因、次生灾害特性以及造成的应急负荷进行了分析研究,构建了灾时危化品事故危机信息管理体系,并提出了过程嵌入、信息融合以及学习分享的三大运行机制,以期实现该体系的高效运转。     

《化工容器设计》教学改革与探索简

《化工容器设计》是过程装备与控制工程专业的核心课程之一,其教学目的是培养学生具有进行化工容器工程设计的初步能力。研究提出了精选基本内容、扩充设计方法,增设反映现代科学技术成果、最新科学研究成果的教学设计项目等教学内容改革;用现代科学技术和手段改造传统授课理念、增加应用计算机教学以及激发培养学生创新思维等教学方式改革。运用改革的教学内容和教学方式,教学效果得到了明显的提高。     

从广西第五次人口普查看人口迁移状况

本文根据2000年人口普查10%数据带汇总的结果,认为广西人口迁移呈上升趋势,且增长速度较快;迁出人口远大于迁入人口。在迁移人口中,以劳动适龄人口为主,女性人口占多数,以初中文化程度最多,迁移者大多是商业、服务业人员,农林牧副渔水利业生产人员和生产、运输设备操作人员。务工经商是促成人口迁移最直接的动因。人口迁移是广西农村发展重要的资金来源和经济增长点,加快了广西城市化进程。但人口迁移产生了人口分布失衡、人才流失等负面影响。因此,我们应通过户籍制度改革、加强中心城市功能建设、制定和实施科学的人才流动政策等措施,促进广西人口迁移的良性运行。     

Time series models associated with Mittag-Leffler type distributions and its properties

ABSTRACT

We have provided a fractional generalization of the Poisson renewal processes by replacing the first time derivative in the relaxation equation of the survival probability by a fractional derivative of order α(0 < α ? 1). A generalized Laplacian model associated with the Mittag-Leffler distribution is examined. We also discuss some properties of this new model and its relevance to time series. Distribution of gliding sums, regression behaviors, and sample path properties are studied. Finally we introduce the q-Mittag-Leffler process associated with the q-Mittag-Leffler distribution.     

On the Choice of Functional Forms: Summary of a Monte Carlo Experiment

The use of flexible functional forms is a standard practice in applied econometrics. Many flexible forms have been proposed. In this study, we investigate the behavior of three of them—the translog, the symmetric McFadden, and the symmetric generalized Barnett. Based on Monte Carlo experiments, we assess the ability of these forms to test theoretical properties and to measure technological characteristics.