Performance of shallow anchor in ice-rich silt

Thesis (M.S.) University of Alaska Fairbanks, 2014Shallow anchor systems have been widely used for decades due to their time and cost efficiency. Yet when it comes to cold regions like Alaska, new challenges caused by the harsh environment need to be resolved before they are used extensively in cold regions. One challenge associated with anchor installation could be the potential thawing of warm permafrost due to the grout mortar hydration, which might undermine the capacity of the anchor. Another challenge is that due to low temperature the grout may cure slower or not cure at all, which will also result in a significant decrease in the ultimate strength of the anchor. Field tests were conducted to evaluate the performance of shallow anchors including duckbill anchors and grouted anchors with three types of different grouting materials, including Microsil Anchor Grout, Bentonite Clay and a newly-developed Antifreeze Grout Mortar. Constant-load creep test and pullout test were conducted to evaluate the performance of the anchors. Test results indicated that the anchors grouted with Antifreeze Grout Mortar caused the least permafrost disturbance and degradation, gained the largest tensile strength, exhibited the least creep displacement, and showed relatively large pullout capacity, and thus achieved the best performance among all types of shallow anchors

Construction of Subject Service Innovative System Based on the Restraint of Information Flow

将信息流概念引入学科服务中,以决定信息流系统的两个关键因素,即以内容和架构为基础,探讨了学科服务中服务资源和服务架构的创新建设,构建了基于信息流约束机制的高校图书馆学科服务创新体系。以期推动学科服务成为高校学科建设中不可或缺的一环。The concept of information flow was introduced to the subject service.There were two key factors affecting the system of information flow, including content and framework.The paper discussed the innovative construction of service content and service framework, and established university libraries' subject service innovation system based on the restraint of information flow, so as to promote the subject service becoming an essential part of universities' subject construction

Thinking About the Construction of Institutional Repository in Xiamen University Library

目前,如何有效管理不断增多的学术资源且提高学术典藏库利用率,已成为厦门大学学术典藏库急需解决的问题。随着厦门大学科研事业的发展,各学科科研团队作为科研主体,提出了在已建设的厦门大学学术典藏平台基础上,由图书馆学科馆员以科研团队为单位有效管理学术典藏库的意见。因此,本文对厦门大学图书馆学术典藏库建设与服务进行思考,以期能更好地为科研团队提供各种有效的信息服务。Now it's urgent for Xiamen University Institutional Repository(IR) that how to manage the academic resource in an effective way and increase resource utilization rate.With the development of research of Xiamen University, as the main part of scientific research, different kinds of research teams have suggested that the subject librarians should divide resources into several parts based on their teams.Therefore the paper mainly raised the thinking about the constructions of Xiamen University IR to service effectively for research team

survey on transformation-based large graph visualization

大图可视化是信息可视化领域的前沿课题之一,也是在线社会网络、信息安全、电子商务等热点行业大数据分析的重要支撑技术.基于变换的大图点边可视化方法由于其具有在线处理时间短、可视复杂度低、交互方法灵活多样等优点,近年来在学术界与实际商用系统中得到广泛重视与应用.文中从图可视化的基本概念及其在大图上的关键挑战出发,梳理了基于变换的大图点边可视化方法的典型分类与主要流程;通过详述3类基于变换的大图点边可视化典型方法(图数据抽象、视图变换与视角转换),阐明了不同方案的优缺点与适用场景,并进一步指出了未来工作的可行方向与潜在难点.国家“九七三”重点基础究发展计划项目(2010CB328105)|国家自然科学基金(60932003,60973144

中国城市化对外商直接投资影响的实证检验

文章结合我国城市化的实际情况,对城市化进程对fdI的影响进行了探究。通过对我国1990~检验2008年省级面板数据分别进行时间分段回归和整体回归,其结果显示,在各种因素的相互作用下,我国城市化进程与外商直接投资之间存在着显著的倒n型关系

GLS Estimator for Random Effect Based on Lattice Search

面板数据随机效应模型两步回归法参数估计使用的方差分量来自第一步的回归估计,它没有考虑方差分量的精度。为了弥补这一缺陷,故提出最优方差分量法(OPTIMAl VArIAnCE COMPOnEnT),简称OVC。OVC方法增加了“格点搜索“技术,能够提供更多的方差分量组合,因此在一定程度上提高了参数估计的精度。蒙特卡罗模拟的结果虽然支持上述论点,但该方法却存在一定的问题,仍有待进一步完善。The Variance Components used in two-step regression parameter estimation for random effect model of panel data are extracted in the first step of estimation,the validity of Variance Component are not considered.To cover the shortage,the paper suggests Optional Variance Component,shorted for OVC.OVC adopts "lattice search" technique;it provides more combinations of variance components,so it can improve the validity of estimators to some degrees.The result of Monte Carlo simulation study supports the above argument,but the OVC exist some problems,it should be improved further