举家外出的农民工融入城市问题研究 ——对在北京务工的500个农民工家庭的访谈数据分析

本文对目前在北京就业的农民工融入城市的现状和程度进行了实证分析，分析数据来源于2004年开始的、每2年进行一次的、在京就业的500个“80后”农民工市民化程度的跟踪调查和入户访谈。在对2010年11月-2011年3月调研数据进行描述性统计的基础上，笔者选择了因子分析方法，量化分析了农民工融入城市的程度，得出了制度上的限制、流动就业的类型和个人的资源禀赋条件是影响农民工融入城市的主要因素的结论。     

Industry Structure and Corporate Debt Maturity

We examine how industry competition affects firms’ choice of short‐term debt. We find that the percentage of short‐term debt is positively related to industry concentration at low levels of concentration, and inversely related to industry concentration at higher levels of concentration. This nonlinear relation is stronger in industries where firms are either more homogeneous or compete more aggressively. Moreover, we find that firms with shorter‐maturity debt are less aggressive than their rivals in the product market. The overall evidence suggests that although financial contracts alleviate agency problems, they exacerbate the risk of predation.     

产业集聚的机制与效应分析——以河南省数据为例

本文改进了Ellision和Glaeser定义的地理集中度指数,建立了产业集中度指数并对河南省2003-2009年20个产业的集聚程度进行了测算。我们的结论是,河南省20个产业在2003-2006年间总体集聚程度提高,在2006-2009年间集聚程度大幅下降;河南省产业集聚程度变动的机制与各产业拥有的垄断优势强弱呈正相关关系;这种垄断优势不一定是大企业所特有的,中小企业如果在技术、管理和品牌方面拥有垄断优势也会加强产业的集聚程度,相反大企业仅仅生产规模大而没有其他的垄断优势,则产业的集聚程度会减弱。Porterd和Krugman的产业集聚促进经济增长的理论并不适合所有的产业;产业集聚如果要促进产业和经济的增长,关键是要培育产业在全国范围内技术、资本、管理和品牌方面的垄断优势;河南省总体的垄断优势在全国有弱化的趋势,因此加紧培育产业的垄断优势就成为河南省乃至各地区经济发展的一项重要任务。     

高职院校学生求学满意度的探究

高职院校提供了一种以学生为中心的教育服务模式,将学生作为高职院校的直接顾客。本文分析了高职院校学生求学的特点,初步设想了高职院校学生求学满意度模型,给出了提高高职院校学生求学满意度的建议。     

20Kt/a煅烧焦回转窑耐高温下料溜管技术改造的研究

介绍在大港油田20Kt/a煅烧焦厂煅烧回转窑高温下料溜管的投产使用中,针对出现的焊口开裂、高温下管体变形等一系列问题,通过焊接应力分析、高温温差应力、溜管整体结构受力分析等方法和原理,从整体结构和焊接方法两方面进行技术改造,探讨出符合大港油田20Kt/a煅烧焦60米回转窑使用要求的耐高温下料溜管制作安装方法。     

Lagrange插值多项式平均算子的逼近

本文引入以第二类 Chebyshev 多项式 U_n(x)的零点为基点的 Lagrange 插值多项式平均算子 F_n(f,x),研究用 F_n(f,x)逼近连续函数 f(x)的阶。     

电子商务对企业内部权威分配的影响分析:以中石油、中石化为例

如今“电子商务”不再是一项单纯的技术进步，而更多地意味着企业经营管理模式的升级换代。在电子商务如何影响企业组织方面．目前很少有研究关注电子商务的发展带来的对企业内部权威分配尤其是对集权与分权安排的影响。本文以中国石油和中国石化两个传统行业企业发展电子商务的历程为案例．分析了在电子商务的环境下，企业权威分配将如何发生变化。本文认为，电子商务影响了内部交易成本（信息成本、代理成本等）。特别是带来了内部信息成本的降低，从而使企业的最优权威分配向相对集权方面转变。同时．这种组织结构上的变化将为企业带来规模经济效益、市场力量加强、降低内部竞争、降低监督成本等绩效。     

News from the Monopoly Front: Changes in Industrial Concentration, 1992–1997

Comparing concentration ratios between 1992 and 1997 raises difficulties because the 1997 data are arranged according to a new industrial nomenclature. By comparing concentration ratios in industries where the definition did not change, it is possible to make comparisons of changes in concentration between the two years and to document the considerable changes in industrial structure in the manufacturing and retail sectors.     

Advertising, Its Determinants, and Market Structure

This study derives a formal model of firm advertising behavior and applies it to the industry level to figure out the relationship between advertising and market structure. The firm advertising model shows that both consumer preference andfirm-specific advertising competence jointly determineprofit-maximizing advertising intensity. At the industry level, advertising intensity is represented multiplicatively by consumer preference and a measure of market structure, which reflects the joint distribution of the levels of advertising competence and market shares among firms. The new market structure measure suggests that those single-dimensional measures of market structure such as seller concentration and the Herfindahl index are inadequate in explaining interindustry differences in advertising intensity, and that the long-debated advertising-concentration relationship differs depending primarily on the appropriability of advertising. An empirical analysis of 426 five-digit Korean manufacturing industries shows that an inverted U-shaped relationship between the Herfindahl index and industry advertising intensity is observed for consumer goods industries but a lazy J-shaped relationship for producer goods industries.     

Market Power,Efficiency and the Dispersion of Systematic Risk

A number of studies have used the Capital Asset Pricing Model (CAPM) to integrate product market and financial theories of the firm. We reexamine the relationship between product market structure and systematic risk at the firm and industry level. We show that theory yields no testable implications at the firm level. We show, however, that there is a relationship between the intraindustry dispersion of systematic risk and industry concentration which depends on the causes and consequences of concentration. Estimates of the relationship between the intraindustry variance of and concentration for a 1987 cross-section of U.S. industries suggest that concentration allows larger firms to exercise market power.