Costly state verification and debt contracts: a critical resume

This paper presents a critical review of the Costly State Verification framework starting from the basic model by Gale and Hellwig [Review of Economic Studies 52 (1985) 647] and further examining the most recent developments. It aims both at discussing the optimality of debt contract in alternative contexts and at offering a reply to the critiques usually moved to this approach within a unified framework.     

How Should An Accumulative Toxic Substance be Banned?

The harmful effects on human health or ecosystems of many toxic substances depend on their cumulative concentration in the carrying medium (water, soil, or air), not just on the annual deposition rates of the substances. Accumulative toxic substances pose challenges to regulatory policy that are not faced when controlling pollutants whose damaging effects are though to depend primarily on annual emission flows. An increasingly common response is to phase out offending uses or production of the substance. In this paper we take as given the goal of phasing out an accumulative pollutant and examine different ways this could be done using a simple, partial-equilibrium dynamic model. We focus on phaseout measures in which the cumulative production and release of the offending substance over the transition period is fixed. Once this cumulative volume is reached, users must convert to a known but higher-cost substitute that is assumed to be benign. The key to the analysis is the observation that the quota on cumulative production makes production of the toxic substance during the transition analogous to extraction of an exhaustible resource with a higher-cost, nonexhaustible ‘backstop’ technology. Using this framework, we first describe the cost-effective outcome when the ‘sunset’ date is chosen to maximize product market surplus subject to the cumulative production constraint. This outcome is compared to one in which the regulator fixes the sunset date, and one in which the regulator limits annual production as well as cumulative production out of concern for acute exposure effects. Finally, we discuss the kinds of market-based policy instruments that would be appropriate for supporting a cost-effective outcome.     

基于可持续发展准则的绿色城市设计交通策略——来自《绿色城市主义》的启示

针对当前我国城市交通面临的现状和困境,急需探索一种可持续发展的绿色交通途径和方法。论文重点介绍了欧洲城市所采取的公共交通优先、小汽车友好型城市和低技生态型自行车交通等改善城市交通的策略,以期为我国可持续发展的城市交通规划建设提供借鉴与参考。     

大粒径沥青碎石LSPM-35基层施工技术

文章结合工程实例,介绍大粒径沥青碎石的概念、材料性能技术要求、配合比设计、施工工艺和质量控制。     

对抗震验算公式γ_0s≤R的探讨

文章通过对截面抗震验算公式和非抗震承载力设计的一般公式中系数的不同的比较,对构件承载力抗震调整系数作出解释,并说明结构构件重要性系数不出现在结构构件的截面抗震验算公式中的原因。     

The Child as Learner, Critic, Inventor, and Technology Design Partner: An Analysis of Three Years of Swedish Student Journals

From Autumn 1998 to Spring 2001, 27 Swedish children (14, at age 5 and 13, at age 7) partnered with an interdisciplinary and international group of researchers supported by a grant from the European Union to create new storytelling technologies for children. After each of the many design activities, children were asked to reflect with drawings and/or writing in a bound paper journal. As the project concluded in the third year, the children's journals were analyzed and four constructs emerged from the data: learner, critic, inventor, and technology design partner. This study examines the motivation for such a research and learning experience, describes the changes in roles we saw represented in our child partners' journals, and suggests possible future directions for educators and technology developers. This revised version was published online in July 2006 with corrections to the Cover Date.     

汽车装配物流输送机系统结构的优化设计与应用

通过对输送机承载小车轴承提前失效现象的理论分析,得出其主要失效原因是轴承自身强度不足及润滑不良。由此症结寻求对策：设计非标整体轴承滚轮,辅以油嘴油槽加注油脂以改善轴承润滑,从而达到延长轴承使用寿命的目的。     

Adding Value to the Teaching and Learning of Design and Technology

It has been argued that design and technology can be used as a vehicle for teaching science and vice versa. In this paper, we report an investigation into Grade 6 students understandings of concepts embodied in the Systems strand of a technology syllabus as they grappled with a unit of work in technology for the first time. The unit of work involved students in the design and construction of simple systems, followed by experiences with more complex systems. Qualitative research methods were used to investigate the activities of the students as they engaged in the design and technology learning experiences for eight weeks. Data sources included student and teacher interviews, video and audio recordings of whole class and small group interactions, students notes, drawings and diagrams, and researchers field notes and reflections. Changes in students ability to identify the individual components and analyse how the components worked together in systems, and evidence of students use of scientific understandings for explanations, were noted as the unit of work progressed. An improvement was observed in students abilities to describe relationships between inputs, processes and outputs, and outline sequences of cause and effect. The technology and science appeared to be complementary as they developed technology specific and action-oriented technology and science language, which may be evidence of the presence of a community of learners. Recommendations are proposed for enhancing the value of both design and technology and science if both subjects are taught together as part of an integrated program in primary schools.     

高校财务管理专业“专业实验”教学环节设计构想

文章列举了财务管理专业实践性教学环节改革的两种模式,介绍了嘉兴学院财务管理专业“专业实验”教学环节设计的经验。