关于矿产资源开采顺序的经济分析与政策调控

在局部均衡的理论框架下,研究了资源矿山拥有者对不同品位矿山的最优开采顺序,得出如果以利润现值最大化为目标,那么矿山拥有者必须按照开采成本的递增顺序开采,并分析了税收对开采顺序的影响,指出政府可以通过征收资源收入税改变资源的开采顺序.     

A short history of global inequality: The past two centuries

Using social tables, we make an estimate of global inequality (inequality among world citizens) in early 19th century. We then show that the level and composition of global inequality have changed over the last two centuries. The level has increased reaching a high plateau around 1950s, and the main determinants of global inequality have become differences in mean country incomes rather than inequalities within nations. The inequality extraction ratio (the percentage of total inequality that was extracted by global elites) has remained surprisingly stable, at around 70% of the maximum global Gini, during the last 100 years.     

印刷线路板浸出液中铜的提取研究

对从印刷线路板(PCB)浸出液中提取铜做了一系列研究。通过降酸处理得到适合萃取的浸出液,考察了不同相比对铜萃取率和反萃率的影响,并对浸出液的杂质含量进行了分析测定。结果表明:将硫酸介质的浸出液蒸发结晶后的硫酸铜晶体用水重新溶解,所得的待萃液酸度降低,达到萃取条件。在相比O/A=2∶1下,萃取6级,总萃取率可达99.7%。用3mol·L-1的H2SO4,相比O/A=2∶1经过4级反萃,总的反萃率可达98.08%。含铜反萃液经处理后,得到纯度为98.5%的硫酸铜产品。     

主成分分析法在企业绩效综合评价中的改进

通过对主成分分析法(PCA)基本算法的分析,从企业绩效综合评价的角度出发,指出了在指标变量的多重相关性处理、定性指标定量化、原始数据无量纲化等方面存在的弊端,引入了分级指标体系的设计方法、数量化理论(Ⅲ)、分类无量纲化方法解决之。针对PCA中特征向量方向的确定问题,提出了特征向量方向确定的原则。针对主成分的提取和权重赋值问题,提出了优先递阶提取法和两两比较判断矩阵法解决之。最后,针对线性PCA的结构化问题,探讨了当今研究的方向和思路。     

Unions: Rent Creators or Extractors?*

This paper proposes a model of workplace‐specific unions that integrates two views of what unions do. One view holds that unions mainly engage in rent extraction. Another view holds that unions mainly engage in rent creation by providing agency services that increase workplace productivity. We demonstrate that the choice between the two activities is systematically related to the economic and regulatory environment in which the union operates. Product market competition encourages rent creation, while labor market deregulation encourages rent extraction. Moreover, we provide a rationale for why firms may want to subsidize unions.     

浅谈计算机技术与生物技术在应用中的相互作用

本阐述了计算机技术和生物技术的出现、发展及两种技术在发展过程中的相互渗透、相互作用，揭示了计算机技术在生物技术从DNA分子结构的理论借鉴，到描绘基因图谱与DNA测序中的数据计算中所起的关键作用，以及生物技术对DNA计算机技术发展方向的影响。     

满山香提取工艺的研究

文章采用正交试验设计方法,选择药材的破碎度、乙醇倍数、乙醇浓度和渗漉速度4个因素,每个因素选3个水平对满山香渗漉提取工艺进行最佳工艺条件的研究。实验结果表明,满山香细粉的颗粒直径为1～2mm、乙醇量为药材量的6倍、乙醇浓度为60%、渗漉速度4～5ml/min为最佳提取工艺参数。该工艺方法对满山香的提取及开发应用具有一定的指导意义。     

The economic impact of shale gas extraction: A review of existing studies

Recent advances in drilling technology have allowed for the profitable extraction of natural gas from deep underground shale rock formations. Several reports sponsored by the gas industry have estimated the economic effects of the shale gas extraction on incomes, employment, and tax revenues. None of these reports has been published in an economics journal and therefore have not been subjected to the peer review process. Yet these reports may be influential to the formation of public policy. This commentary provides written reviews of several studies purporting to estimate the economic impact of gas extraction from shale beds. Due to questionable assumptions, the economic impacts estimated in these reports are very likely overstated.     

Ex-post full surplus extraction,straightforwardly

Consider an estimate of the common value of an auctioned asset that is symmetric in the bidders’ types. Such an estimate can be represented solely in terms of the order statistics of those types. This representation forms the basis for a pricing rule yielding truthful bidding as an equilibrium, whether bidders’ types are affiliated or independent. We highlight the link between the estimator and full surplus extraction, providing a necessary and sufficient condition for ex-post full surplus extraction, including the possibility of independent types. The results offer sharp insights into the strengths and limits of simple auctions by identifying the source of informational rents in such environments. Harstad acknowledges hospitable accommodation by the Fuqua School of Business, Duke University, and the Olin School of Business, Washington University in St. Louis, during parts of this research. We are grateful for comments and suggestions from Richard McLean and Jeroen Swinkels.     

基于遗传算法的核函数参数优化

核主分量分析是一种输入输出特征非线性变换技术。选择最优或接近最优的非线性变换核函数参数,使类的可分性测度最大,是KPCA应用于特征提取的关键。本文采用高斯变异遗传算法作优化技术,实现了KPCA和GA的集成,适合核函数参数的优化选择。仿真表明,该技术可行、有效。