大倾角采煤技术的相关探讨

我国大倾角煤层不仅分布广,地质条件、资源储量和需煤程度差别也很大。文章基于我国开采大倾角煤层的各种不同客观因素,探讨了多种大倾角煤层的采煤方法及其相关技术。     

应对金融危机 发挥深圳支柱企业作用

2008年延续至今的全球金融危机对中小企业聚集的深圳经济造成较大冲击。应对这场危机,深圳必须强化支柱企业优势,发挥支柱企业较强抵御风险的作用。与京沪相比,支柱企业对深圳的贡献作用明显偏低。笔者认为,深圳要充分发挥本土支柱企业的作用,通过优质资源向优质企业倾斜,优惠政策向支柱企业倾斜的政策扶持支柱企业的发展,以增强深圳抵御经济危机的能力。本文最后就深圳依托支柱企业发展物流装备业提出了一点建议。     

社会固定投资与居民福利量化关系模型分析

固定资本投资是流动资本投资的前提和基础，也是整个社会经济规模扩张与发展所必须依赖的重要物质基础。现期厂商的固定资本投资会直接导致本期总需求的增加，在保持总供求平衡的前提下，政府本期的调控货币投放规模将会相应减小，从而影响本期社会弱势居民的福利水平。     

Neglected dynamics in panel data models; consequences and detection in finite samples*

The bias of various estimators for static cross-section and panel data models is assessed in a simulation study, where the actual data generating process is a dynamic adjustment mechanism with random individual effects. It is concluded that the consequences of incorrectly estimating a static model can be rather serious. Therefore, it is important to have an accurate technique available for the detection of dynamics. Two exact similar tests for the presence of a lagged dependent variable in panel data models are developed; in some simulation experiments these tests outperform standard asymptotic test procedures. Empirical results on Engle curves for food illustrate the above issues.     

Stochastic growth: asymptotic distributions

Summary. This note studies conditions under which sequences of state variables generated by discrete-time stochastic optimal accumulation models have law of large numbers and central limit properties. Productivity shocks with unbounded support are considered. Instead of restrictions on the support of the shock, an “average contraction” property is required on technology. Received: August 27, 2001; revised version: January 9, 2002 RID="*" ID="*"The author thanks John Creedy and Rabee Tourky for helpful comments, and the Economic Theory Center, University of Melbourne for financial support.     

关于城市社区管理模式改革的几点设想

城市社区管理模式改革的基本条件已具备;城市社区管理模式改革应适当扩大社区规模,在“自治”原则下,理顺关系,建立起科学的管理与服务体系,并建设一支专业化的城市社区管理队伍。     

大刃倾角外圆精车刀的工作原理及应用

大刃倾角外圆精车刀有着显著的优点——加工表面粗糙度可达 Ra0 .4以下 ,“以车代磨”大大提高了生产效率。本文阐述了大刃倾角外圆精车刀的工作原理及实际应用实例     

基于层次分析法的科技财政支出绩效评价研究

本文根据科技财政支出的特性，依据层次分析法原理，对科技财政支出的绩效评价建立了具体的评价指标体系，选择了适于反映科技支出效益的指标群，并运用层次分析法对科技财政支出绩效进行了示范性评价计算。     

THE IMPACT OF GOVERNMENT EXPENDITURE ON GROWTH: EMPIRICAL EVIDENCE FROM A HETEROGENEOUS PANEL

This paper investigates the impact of government expenditure on growth, in a heterogeneous panel, for a sample of developing countries. Using generalized method of moments techniques, we show that countries with substantial government current expenditure have strong growth effects, which vary considerably across the nations.     

大功率紧凑型行星机构的设计

国内薄层复杂地质煤层的开采,需要适应该煤层的采煤机结构小,功率大。由于结构限制,传统的行星机构结构已经无法满足大功率,小结构的要求。本文介绍一种改进结构的行星机构,该机构具有承载能力大,结构紧凑等特点。