横断面测量在广州轨道交通工程中的应用

简述横断面测量在广州轨道交通四号线大学城专线工程中目的、方法和精度等,并根据大学城专线工程沿线不同范围、形状、特征,较详细分析断面测量在车站、区间、隧道等结构内具体间距、测点布置,运用横断面测量成果,为设计调线调坡和机电安装提供准确净空数据.     

Panel unit root tests under cross-sectional dependence

In this paper alternative approaches for testing the unit root hypothesis in panel data are considered. First, a robust version of the Dickey-Fuller t -statistic under contemporaneous correlated errors is suggested. Second, the GLS t -statistic is considered, which is based on the t -statistic of the transformed model. The asymptotic power of both tests is compared against a sequence of local alternatives. To adjust for short-run serial correlation of the errors, we propose a pre-whitening procedure that yields a test statistic with a standard normal limiting distribution as N and T tends to infinity. The test procedure is further generalized to accommodate individual specific intercepts or linear time trends. From our Monte Carlo simulations it turns out that the robust OLS t -statistic performs well with respect to size and power, whereas the GLS t -statistic may suffer from severe size distortions in small and moderate sample sizes. The tests are applied to test for a unit root in real exchange rates.     

Why do companies transfer the trading compartment of their common stocks

We analyze the motives and determinants of voluntarily stock exchange section switching on the NYSE Euronext. By strategically deciding trading-section transfer when it is beneficial, managers expect to reduce their liquidity and invisibility costs, cost of capital, or their listing costs. We show that managers decide to change the trading compartment of their common stocks based on various factors including firm's size, liquidity level, debt ratio, and expected growth opportunities. Firms that move voluntarily from a less or non regulated compartments to a more regulated one are likely to have transferred to increase their credibility, improve their stocks’ liquidity, re-balance their leverage, and to finance their growth opportunities. Whereas those that move their common stocks toward a less-regulated compartments do it mainly for costs saving reasons.     

大断面煤层沿空巷内支护加固技术研究

地下岩体在开采之前,由于自重和构造所引起的应力是处于平衡状态的,当掘巷道或者进行回采工作时,就破坏了原来应力的平衡状态,使岩体内部应力重新分布,具体表现在巷体周围的煤、岩体产生移动、变形,直到煤和岩体内部形成新的应力平衡状态为止。在煤的开掘过程中,由于采掘活动引起巷道围岩应力集中和重新分配,为了防止围岩变形遭到破坏,需要对围岩进行支护和加固。本文就大断面煤层沿空巷内支护加固技术进行研究,以便为煤矿在开采过程中积累一些技术和经验。     

关于公路与桥梁之间过渡段施工技术初探

本文主要分析了公路桥梁间过渡段出现不均沉降的原因以及公路桥梁间过渡段的施工技术的应用情况,此项技术对降低施工成本,提升桥梁的可靠性与安全性有重要作用。     

济南市古生物化石赋存特征及保护区划研究

为贯彻《古生物化石保护条例》,提高济南市古生物化石保护水平,在对区内古生物化石资源进行野外勘查和综合整理的基础上,依据古生物化石鉴定结果及其赋存地层分布特征,得出济南市古生物化石的分布特征,划分了古生物化石产地,选择化石完整程度、富集程度、剖面出露程度、周边地质环境、工程活动影响五个评价因子,运用综合指数法,建立了符合济南实际的古生物化石保护区划分体系,将区内古生物化石产地进行了保护区分级,并按照“保护优先,结合实际”的原则,制定了符合济南市实际的古生物化石保护措施。     

某大型立交桥工程结构设计及关键施工工序研究

该文从桥梁关键施工工艺出发,对立交桥关键结构的设计及施工工艺进行了细致的讨论,解决了施工过程中施工人员遇到的部分实际问题,为指导安全施工提供了技术上的支持。     

论和谐社会视野中水库管理部门纪检监察工作的开展

纪检监察机关肩负着反腐倡廉为构建和谐社会提供纪律保证的艰巨任务,必须深刻理解构建社会主义和谐社会这一全新执政治国理念的重大现实意义和深远历史意义。本文分析了在建设社会主义和谐社会的大背景下如何展开水库管理部门纪检监察工作的对策。     

地铁PBA车站大断面倒挂井壁施工工法的应用研究

地铁工程倒挂井壁法多用于隧道区间临时竖井、暗挖车站临时竖井及区间联络通道处,长春地铁1号线一期工程长春火车南广场站车站PBA暗挖段受新建地下三层全盖挖逆作法长春火车站综合交通换乘中心南广场工程、地下一层既有春华商场地下人防改造影响,工期滞后先完成全盖挖逆作法综合换乘中心南广场工程和负四层地铁盖挖段车站结构后,再由车站小...     

预应力锚索工作性状数值模拟分析

预应力锚索作为一种有效的岩土体支护技术,在软土场地中的应用较少,但是该结构的经济性较好,在一些软土基坑支护中得到应用.为了分析预应力锚索在软土场地中的工作性状,通过数值模拟手段计算了预应力锚索的轴力分布、锚固段长度的影响等问题,得出锚索在岩体和软土中的工作状态存在差异,因此实际应用中应区别对待.