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.     

The persistence of knowledge‐based advantage: an empirical test for product performance and technological knowledge

Resource‐based theory maintains that intrinsic characteristics of resources and capabilities, such as their tacitness, complexity, and specificity, prevent imitation and thereby prolong exceptional performance. There is little direct evidence to verify these claims, yet a substantial literature encourages firms to formulate competitive strategies around resources with these attributes. Further, work outside the resource‐based tradition suggests that these attributes can slow innovation, and it is not clear when this effect outweighs the benefits of inimitability. This paper seeks to clarify whether and how the complexity, tacitness, and specificity of a firm's knowledge affect the persistence of its performance advantages. We find that the complexity and tacitness of technological knowledge are useful for defending a firm's major product improvements from imitation, but not for protecting its minor improvements. The design specificity of technological knowledge delayed imitation of minor improvements in this study. Copyright © 2002 John Wiley & Sons, Ltd.     

建立静脉物流系统推进循环经济发展

本文立足于静脉物流,引入循环经济的理念,阐述静脉物流与循环经济的关系.通过静脉物流系统的建立,发展我国循环经济,实现从传统线性经济模式向循环经济模式的转变,使我国经济得以可持续发展,同时有利于人类与环境、自然资源的共生.     

Learning in Design and Technology: The Impact of Social and Cultural Influences on Modelling

The paper introduces the highly problematic nature of modelling in design and technology education and examines the relationship between cognitive and concrete modelling. Its aim is to gain insight into what learners do, rather than what others say they ought to do in their learning activities. The variety of purposes that educators have for learners’ modelling are discussed through examining the contested curriculum justification for design and technology education itself. The paper proposes that learners’ modelling cannot be extracted from the social milieu in which they act and it provides some insights of these social influences through the analysis of two case studies. Their settings are a girls’ secondary school and a college of higher education. Each case study is presented independently but organised with a common format to consider a) the impact of assessment on learning intentions and outcomes; b) cultural influences on learning and modelling; c) social influences on learning and modelling. A discussion of the emergent themes considers implications for teachers. This revised version was published online in July 2006 with corrections to the Cover Date.     

Another view on optimal design for estimating the point of extremum in quadratic regression

In this paper we illustrate how certain design problems can be simplified by reparametrization of the response function. This alternative viewpoint provides further insights than the more traditional approaches, like minimax, Bayesian or sequential techniques. It will also improve a practitioner’s understanding of more general situations and their “classical” treatment.     

技术站运输分析管理信息系统设计

在对我国铁路技术站运输分析手段和管理信息资源进行分析的基础上,提出技术站运输分析管理信息系统的设计,充分利用和整合技术站铁路运输管理信息系统(TMIS)和办公自动化网络等信息资源,实现统计工作自动化、分析工作网络化和车站作业组织的动态模拟,准确、即时地分析车站运输生产情况,挖掘潜能,为决策提供适时、可靠的依据,适应运输市场的快速变化。     

Construct measurement in strategic management research: illusion or reality?

Strategic management research has been characterized as placing less emphasis on construct measurement than other management subfields. In this work, we document the state of the art of measurement in strategic management research, and discuss the implications for interpreting the results of research in this field. To assess the breadth of measurement issues in the discipline, we conducted a content analysis of empirical strategic management articles published in leading journals in the period of 1998–2000. We found that few studies discuss reliability and validity issues, and empirical research in the field commonly relies on single‐indicator measures. Additionally, studies rarely address the problems of attenuation due to measurement error. We close with a discussion of the implications for future research and for interpreting prior work in strategic management. Copyright © 2004 John Wiley & Sons, Ltd.     

Institutional design and the closure of public facilities in transition economies

As part of the reforms of their systems for financing and delivering health care, many transition economies, particularly in central and eastern Europe, have adopted national insurance funds that are institutionally separate from ministries of health. Most of these countries have also grappled with the problem of restructuring the delivery system, especially the need to reduce hospital capacity. Although improving the performance of medical care providers through a shift from passive budgeting to explicitly incentive mechanisms is important, why this change in financial relations between the government and providers could not be implemented simply by reforming the role of health ministries is not obvious. This paper presents an explicit rationale for the separation of powers between the regulator (the ministry of health) and the financing body (the insurance fund), based on the inability of a single agency to commit to closing hospitals. JEL classification: L51, P20, P35, I18.     

论旅游市场营销环境与旅游业可持续发展

随着科学技术的高度发展,旅游者的选择性强,旅游活动范围大,使旅游供给者面临越来越激烈的竞争。旅游企业要求得生存和发展必须要对旅游市场进行准确定位,在可持续发展观念指导下开展市场营销活动。创造良好的、协调发展的旅游市场营销环境是实现旅游业可持续发展的基础和保证。     

价值工程在基础优化设计中的应用

本文通过在基础优化设计中应用价值工程理论，分析了基础设计中的功能，成本，价值三方面的关系，从而力求用较低的成本满足必要的功能。