新型陆上快速安装钻井防喷器组装置技术方案

在石油钻井作业中,防喷器起到很重要的作用,从而防喷器组的安装装置也受到关注,钻井现场防喷器组安装方式费时费力,运输不方便且不安全,提高安装装置的自动化,将工人从繁重而不安全的工作中解放出来,保证人身安全是未来的发展趋势。本文从钻井防喷器组运输、安装、拆卸的角度出发,介绍了国内外钻井现场防喷器组安装装置的研究现状;对现有技术全方位的调研和理解,综合考虑目前安装装置的优点和存在的问题;提出了一种钻井作业防喷器组安装自动化水平的解决思路及技术方案;详细阐述了实现钻井防喷器组安装装置的自动化关键技术,以及该装置的模块化设计,包括运输、安装、拆卸;最后展望我国钻机防喷器组安装装置自动化技术发展趋势。     

无拍频控制技术在新一代CRH380CL型高速动车组上的应用

高速动车组技术的迅猛发展对牵引变流器的性能提出了更高的要求。在动车组传动系统中,单相脉冲整流器工作时,会在中间直流环节产生2倍于电网频率的脉动分量,该脉动分量传递到逆变器输出侧会在电机上产生拍频现象,引起转矩脉动和电机过热。     

碎片复写：高强度再利用背景下的首钢 北京冬奥组委总部景观设计营建

当今中国乃至其他国家和地区，对工业旧址采取高强 度再开发的模式已成为趋势，工业建筑及户外场所面临存亡的 巨大挑战，如何认识和尊重工业遗存成为此类后工业改造项目 面临的新课题。随着首钢的搬迁与转型，作为首钢发展的起点 与北部对外门户的西十筒仓区域，成为北京冬奥组委总部落户 之选。面对建筑的先行与价值的不认同所带来的工业体系破碎 化，景观设计重拾了工业系统的价值，在阅读并尊重原有工业 空间逻辑的基础上，对原有地形结构进行创造性复写，并将重 译的工业碎片谨慎地嵌入景观体系中。“碎片复写”设计方式 的提出为高强度开发背景下的工业旧址再利用乃至城市空间更 新如何兼顾科学与艺术、法则与自由提供了策略。     

二阶自回归效应有限时间最优相对保费稳健性

在汽车保险奖惩系统相对保费研究中,需要考虑随机效应的动态异质性。在假设随机效应是一个二阶自回归随机序列的条件下,李俊海、赵振英、常沙沙(2011)给出了有限时间下最优相对保费计算公式,但是没有研究该公式的稳健性。在相同条件下,可以证明该文保费公式的稳健性。     

区域农村贫困格局的形成:空间依赖、空间分异与尺度效应

从“人地关系地域系统”视角,基于等级理论构建了一个分析框架,通过解析贫困空间依赖和分异格局成因的尺度机制（重点关注差异与关联）,来理解宏观与微观因素的相互关系。对甘肃省六盘山片区村级和乡镇贫困进行了计量实证研究,结果表明：(1)行政村尺度对案例区贫困格局及成因的解释度更好,但乡镇尺度上过程不容忽视。(2)宏观经济社会情境因素对微观上村级和乡镇贫困具有显著影响,作用方式具有多元化特点,作用强度在乡镇尺度上大于村级尺度。(3)宏观情境因素与本地因素对贫困格局的形成存在交互增强且因尺度而异的协同关系。另外,还比较了不同等级系统（行政区划系统和重新构建的贫困分区系统、地理分区系统）下的结果差异,发现行政区划系统不是解析贫困格局成因的最佳选择,它会掩盖和扭曲部分因素的影响,而贫困分区系统能更好地描述“真实的”的贫困形成过程。以上表明,中国精准扶贫战略将重心下沉到村和户是现实合理选择,但以“适度漫灌”来夯实宏观上经济基础和补齐公共服务短板在甘肃六盘山片区仍有重要意义,而各级各地政府或组织形成共同但有侧重的协作理念和方式是重要保障。同时,高效可持续的贫困治理在行政机制外尚需强化市场和社会机制。     

Areal differentiation of virtual water for agricultural products and its effect on regional agricultural structure adjustment in China： 1995-2007

With a vast territory, the space-time distribution of water resources is uneven in China. There is a great dif ference in natural conditions and farmland management of agricuttural production in different regions. The areal differentiation of agricultural products virtual water is obvious. Comparison with the agricultural products virtual water from 1995 to 2007 in China shows an increase in the first ten vears and a little decrease in recent years. There has been a tendency of increase all the time in Northeast and Northwest. but a decrease after an increase firstly in other regions. The virtual water offood crops is the maximum which accounts for more than 70% in China. and that of vegetables is in a fast growth. The proportion of agricultural products virtual water to the total water resources in each region has a large difference, showing the imbalance of agricultural water in different regions, which accounts for 50%-90% in Northeast, and 125%-185% in North China. Under the guidance of virtual water strategy, based on the differences of resource endowment, each region should adjust agricultural structure, decide production by water, and select water suitable crops. In water-rich region, agricultural produets of high water consumption should be planted appropriately, which will make full use of the abundant local water resources. In water-shortage region the crop production of high water consumption and low efficiency should be depressed, and that of low water consumption and high efficiency should be supported and increased. It will achieve reasonable disposition of water resources, promote ecological restoration and environmental protection, as welt as ensure food security.     

加强校园文化与企业文化的融合,促进高职学生职业素养的提升

高职学生能否在职场取得成功,不仅取决于他的知识和技能是否扎实,更在于其职业素养的高低。目前,高职生的整体素质难以满足用人单位的需求,其最大不足是爱岗敬业、踏实肯干、与人合作等职业素养欠缺。因此,如何以科学发展观为指导,通过校园文化建设,加强与企业文化的融合,促进学生职业素养提升,这是高职院校教育工作者面临的一个重要课题。     

城镇化视角下的农村人力资本投资研究

本文在分析农村人力资本投资对城镇化的重要作用的基础上,指出了当前农村人力资本投资中存在的影响城镇化发展的种种不足.最后,在城镇化的视角下,提出了改善农村人力资本投资的建议.     

Optimal Tax Policy, Market Imperfections, and Environmental Externalities in a Dynamic Optimizing Macro Model

This paper develops a dynamic real business cycle model that highlights pollution externalities (on welfare and production) and market imperfections and uses it to determine the socially optimal tax policy that encompasses labor income, capital income, and emission taxes. We show that the optimal tax on capital and labor income only addresses the production inefficiency (and is time-invariant), while the tax on the environmental externalities affects both the production inefficiency and the environmental spillovers (and is time-varying). More interestingly, the socially optimal emission tax will be characterized by a Keynesian-like stabilizer that is designed to mitigate business cycle fluctuations, i.e., that will stimulate the economy with a lower emission tax during recessions. In a positive analysis, we show that the beneficial effects arising from pollution taxation will become larger the greater is the degree of the firms' monopoly power. In addition, a triple dividend in terms of improving environmental quality and increasing employment and firms' profit can be simultaneously realized if the environmental production externality is more significant and if the elasticity of intertemporal substitution in consumption is relatively small.     

中国农村性别收入差距变化趋势:1993、1997和2006

运用中国营养与健康调查两个横截面的数据研究了农村劳动力收入的性别差异及其变化情况。农村男女劳动力收入方面存在着明显的性别差异,并且有扩大的趋势。工资回报差异的上升是性别收入差距扩大的主要原因,来自自雇劳动方面的差异则表现为先扩大后缩小收入差距的特点,农业劳动影响不大。