Market efficiency,filter rules and buffer stock profitability

This paper uses a model of the optimum buffer stock as a ‘filter rule’ together with a financial model that can be used to assess the efficiency of international commodity markets. The approach is simpler to apply than many other methods which have hitherto been used and yields an economy in theoretical and computational effort. The arguments are applied as a case study to the international copper market. The main conclusion is that private storage is not under-provided for and that a public buffer stock agency would be unlikely to be self-financing.     

Futures markets and economic efficiency: A theoretical perspective

This article examines the role of futures markets in schieving economic efficiency. The question is introduced in a timeless, certain framework, and extended to the case where time, but not uncertainty, becomes important: it is shown that in such a framework futures markets ensure economic efficiency. Uncertainty is then introduced, and it is shown that contingent markets ensure full efficiency, but that these are cumbersome; it is also shown that futures markets, as an alternative, ensure approximate efficiency. An appendix explores more formally the relation between markets and efficiency.     

从经济效益和生态效益来探索城市土地利用的合理模式

从土地资源的经济和生态特性入手，结合我国土地利用的现状。分析了土地利用的经济效益和生态效益，探讨了既符合市场经济规律、又符合城市可持续发展的土地利用模式。     

改进旋风器结构提高除尘效率的新方法

讨论改变旋风器整体结构，增加附件，改进原有旋风器构件的几种改进结构新做法，分析这些做法提高除尘效率的合理性。     

Comprehensive Assessment of Regional Circular Economy Development Based on Efficiency of Resource & Environment:A Case Study of Jiangsu Province

In the first, the paper gave a retrospective analysis on the comprehensive assessment of circular economic development. According to the requirement of improving resource & environment efficiency, the paper designed an analytical framework for a comprehensive assessment of regional circular economic growth, which consists of the goal, object and technical line of the comprehensive assessment of regional circular economic development. Given that, the paper discussed the criterion for choosing the assessment index, the approaches of index's weighing determination, the means of data standardization, and the reference system of assessment index value and so on. According to the framework of regional circular economic development evaluation,the paper made a comprehensive evaluation of Jiangsu Province's circular economic development. The result shows that from temporal change, Jiangsu Province's circular economic development had different stages;from the spatial comparison, there is variance among different regions, which could be divided into different types according to the spatial variance and the relation between the development of circular economy and the aggregative index number. There was a remarkable correlation between circular economic development level and GDP or the 2nd industry GDP. Finally, the paper gives some suggestions on how to promote the development of circular economy in Jiangsu Province.     

并行时域有限差分法的瞬态声场及其效率分析

建立了适用于二维水下目标声散射声场计算的并行FDTD计算模型,通过计算结果对入射波激励目标的作用过程进行了时域分析,从各个时刻的瞬态声场分布图可以明显看出衍射、透射和散射现象,并且能够直观地给出声场分布形态以及声波传播的物理过程。通过算例测试了其在不同数目节点机参与下的计算耗时、内存耗用、并行加速度和并行效率。分析了计算耗时、内存耗用、并行加速度、并行效率随节点数变化的关系曲线,同时还着重分析了并行效率下降的原因。     

都市型经济开发区生态化建设路径研究

总结了都市型经济开发区的类型和特点,重点分析了都市化经济开发区的生态环境质量制约性因素,提出了从产业生态化建设、土地利用生态化建设、信息现代化建设以及区域环境健康保障体系四个角度分析了生态化建设的路径体系和具体的措施。     

气箱式脉冲喷吹袋式除尘器清灰系统主要技术参数的确定

为了揭示气箱式脉冲袋式除尘器的清灰机理,应用压缩气体流动能量方程,推导出滤袋表面的反向清灰风速教学表达式;根据袋式除尘器实验模型测定的数据,得出了剥离力与粉尘剥离率之问的关系式,并在此基础上提出了清灰系统设计方法;应用气体射流理论得到了脉冲喷吹质量流量、喷吹口直径、空压机供气压力和供气量的计算公式.结果表明,在粉尘负荷一定的条件下,给定预期的剥离率,可以得到所必需的反向清灰风速和喷吹气体流量,据此可以确定清灰系统的主要技术参数.     

浅析锅炉水处理的必要性

锅炉给水不进行处理,必然导致锅炉的结垢和腐蚀。锅炉结垢使锅炉供暖效率降低,严重时可能会造成熔孔或爆管。     

Field experiment on biological contact oxidation process to treat polluted river water in the Dianchi Lake watershed

In this study two types of biological contact oxidation processes (BCOP), a step-feed (SBCOP) unit and an inter-recycle (IBCOP) unit, were designed to investigate the treatment of heavily polluted river water. The Daqing River, which is the largest pollutant contributor to the Dianchi Lake, one of the most eutrophic freshwater lakes in China, was taken for the case study. It was found that the SBCOP had higher adaptability and better performance in the reduction of COD, TN, and TP, which made it applicable for the treatment of polluted river water entering the Dianchi Lake. Nitrification rate was observed to be greatly affected by the influent temperature. During each season, the nitrification in the SBCOP was higher than that in the IBCOP. TN removal efficiency in the SBCOP was higher than that in the IBCOP during the winter and spring but poorer during the summer, possibly due to the inhibition of denitrification by higher dissolved oxygen level in the summer. Moreover, symbiotic algaebacteria growth may be conducive to the removal of pollutants.