精馏过程的节能和优化设计的探讨

精馏过程的节能,对于减少能源消耗,降低生产成本和保护环境具有十分重要的意义.在精馏过程中可以采用最适宜回流比操作和最佳进料状态,使用中间冷凝器和中间再沸器,高效精馏、热泵精馏.合理安排多组分物料分离流程,直接利用过程热量及开发应用高效换热器等措施.本文从最佳回流比R的选择、进料温度及进料状态的确定等方面,详细的分析了在精馏塔的设计过程中,如何实现设计的优化问题,以实现节能降耗.     

新形势下我国耕地保护的长效机制研究

耕地是人类赖以生存的物质基础，是国民经济和社会发展的宝贵资源，耕地数量的多少和质量优劣直接关系到国家粮食安全和社会稳定。因此，在新形势下，如何保护好有限的耕地资源，促进经济社会科学、合理地发展，已成为当今世界的重大课题。本文根据我国耕地减少的现实危机及原因，提出一套科学、合理的耕地保护长效机制，力求为进一步有效地保护耕地资源提供理论基础和现实途径。     

西方现代股利政策理论及实证研究回顾

本文对西方现代公司股利政策方面的理论和实证研究进行了一个综合性的回顾和分析。其中包括主流的股利行为模型、股利的信息内涵、代理成本、追随者效应,也包括国内研究中较少涉及的债务约束、声誉学说、成长机会和交易成本问题,以期对国内相对落后的股利政策研究和随意性较强的股利政策制定带来一定的借鉴意义。     

A consumer education programme based on the Transtheoretical Model of Change

MONEY 2000? is a successful consumer education programme that was implemented by Cooperative Extension personnel in over two dozen states of the USA between 1996 and 2002. One of the unique features of this programme is that it was based on the Transtheoretical Model of Change (TTM), a framework that has been widely used to study health‐related behaviour changes such as smoking cessation. This paper first describes how the MONEY 2000? programme was developed around major constructs contained within the TTM. Findings are reported from a survey conducted with participants in the first two states that delivered the programme. The findings suggest that several change processes used by MONEY 2000? participants are associated with specific stages of change. In addition, there may be differences in behavioural changes between participants who increased their savings and those who reduced their debts.     

Foreign debt and economic growth

This paper empirically examines the relationship between government foreign debt and the growth rate of per capita GDP based on a total sample of 77 countries, as well as sub‐samples of various regions. Cross‐sectional estimates of the coefficient of foreign debt based on the total sample have a negative sign, but are not always statistically significant. Available data from African countries indicate that foreign debt and the growth rate of per capita GDP were negatively related at a high level of significance. For industrialized and Latin American sub‐samples, this relationship is negative but statistically insignificant. The sub‐sample Asian and other developing countries show a positive but insignificant relationship. JEL classification: F34, H6, O23.     

QUADRATIC TERM STRUCTURE MODELS FOR RISK-FREE AND DEFAULTABLE RATES

In this paper, quadratic term structure models (QTSMs) are analyzed and characterized in a general Markovian setting. The primary motivation for this work is to find a useful extension of the traditional QTSM, which is based on an Ornstein–Uhlenbeck (OU) state process, while maintaining the analytical tractability of the model. To accomplish this, the class of quadratic processes, consisting of those Markov state processes that yield QTSM, is introduced. The main result states that OU processes are the only conservative quadratic processes. In general, however, a quadratic potential can be added to allow QTSMs to model default risk. It is further shown that the exponent functions that are inherent in the definition of the quadratic property can be determined by a system of Riccati equations with a unique admissible parameter set. The implications of these results for modeling the term structure of risk-free and defaultable rates are discussed.     

对小地区失业统计差额比的推定

本文对韩国国内行政区域如市郡区等小地区的失业统计共同差额比进行推定的方法有联合推定量,Woolf推定量和Mantel-Haenszel推定量等。对这个推定量的可信度是通过偏差和平均平方误差的概念来进行比较的。从对京畿地区经济活动人口调查情况看,这个地区内的24个市郡单位行政自治地区的男、女失业率差额比的偏差及平均平方误差是通过本次研究提出的推定程序来推定的。这些推定数的稳定性和效率性可以通过相对偏差和相对平均误差平方根来评价。Woolf推定量或Mantel-Haenszel推定量比联合推定量更为稳定,从其效率性来看三者很相似。     

中国税收流失规模估测

无论地下经济还是公开经济都存在税收流失问题.本文采用一定的方法分别对我国1982-2002年间地下经济和公开经济的税收流失规模进行了估测.从税收流失的规模角度看,我国税收的汲取能力比较弱,蕴涵着很大的税收风险.减少税收流失应作为税制改革的重要目标.     

浙江上市公司总体分析

浙江上市公司从数量上看，占了相当优势，排在全国的第4位，而且至今还未曾有退市的公司；从质量上看，也有较突出的特征，该板块的平均净资产值较高，按上市公司数量排的全国前10位中，排在第1位，达3．23元；从市盈率来看也说明了浙江板块的业绩较好，平均市盈率已达17．66倍。但也存在不足的一面，从对社会贡献的总量来看，还不是很突出，缺乏规模效益。     

FACTORS THAT AFFECT THE LONG‐TERM SURVIVAL OF MICRO,SMALL AND MEDIUM ENTERPRISES IN ETHIOPIA

There is an increasing recognition of the potential importance of micro, small and medium enterprises (MSMEs) for employment, income and poverty reduction in Ethiopia. Although the MSME sector contributes significantly to the national economy, the high failure rate among well established small businesses and enterprises is a matter of major concern. A random sample of 500 small businesses and enterprises selected from five major cities in Ethiopia were followed up for 6 years in order to assess the impact of influential factors that affect the long‐term survival and viability of small enterprises. Hazard ratios estimated from the Cox Proportional Hazards Model were used to quantify the impact of key predictors of survival. Businesses that ceased operation were characterised by inadequate finance (61%), low level of education (55%), poor managerial skills (54%), shortage of technical skills (49%), and inability to convert part of their profit to investment (46%). The study shows that participation in social capital and networking (iqqub schemes) was critically helpful for long‐term survival. Businesses that did not participate in iqqub schemes regularly were found to be 3.25 times more likely to fail in comparison with businesses that did. Results of the study have implications that could be used for developing policy initiatives that are aimed at fostering long‐term growth in small businesses and enterprises.