非对称荷载作用下圆形洞室塑性区边界的近似计算

考虑到隧道围岩塑性区的边界受到中间主应力的影响,通过对Moth-Coulomb和Drucker-Prager两个屈服准则在工程中的运用比较,结果表明在运用Drueker-Prager计算塑性区边界时围岩塑性区增大,证明中间主应力对塑性区有影响。该理论弥补了Morh-Coulomb理论未考虑中主应力对塑性区范围的影响,为工程实践提供更加安全的计算理论。     

顶管施工引起海堤过大沉降的原因分析及补救措施研究

近年来顶管法已成为城市管线建设和改造的主要手段,特别在沿江、沿海地区进行顶管施工不可避免地要穿越海堤,施工期确保海堤安全,保证其结构稳定性及防洪御潮功能是非常关键的。为保证海堤工程安全,顶管施工应对工程进行现场沉降监测,分析海堤产生沉降的原因,过大的沉降要研究海堤的加固补救措施,提出适用的施工方案对其进行加固补救,对比加固前后的沉降数据,验证加固措施的可行性。研究成果对类似的工程具有一定的参考意义。     

Automatic Multi-Document Summarization Based on Keyword Density and Sentence-Word Graphs

As a fundamental and effective tool for document understanding and organization,multi-document summarization enables better information services by creating concise and informative reports for large collections of documents.In this paper,we propose a sentence-word two layer graph algorithm combining with keyword density to generate the multi-document summarization,known as Graph Keywordρ.The traditional graph methods of multi-document summarization only consider the influence of sentence and word in all documents rather than individual documents.Therefore,we construct multiple word graph and extract right keywords in each document to modify the sentence graph and to improve the significance and richness of the summary.Meanwhile,because of the differences in the words importance in documents,we propose to use keyword density for the summaries to provide rich content while using a small number of words.The experiment results show that the Graph Keywordρ method outperforms the state of the art systems when tested on the Duc2004 data set.     

公路路面施工中沥青摊铺的施工技术分析

本文结合作者多年的施工经验,分别从沥青摊铺的技术特征、摊铺前的技术准备工作、摊铺施工过程中的技术运用以及摊铺完成后的测查等阶段,综合分析了沥青摊铺技术在公路路面施工中的运用,以期为同类工程提供借鉴.     

多用途液化气船BOG再液化系统流程模拟分析

从装载多种液货的角度出发,选择单级压缩与两级压缩中间完全冷却系统相复叠的形式组成新的再液化系统。运用流程模拟软件Aspen Plus模拟设计的多用途液化气船再液化系统各模块装载不同液货,分别对再液化系统的循环效率、制冷系数和压缩机能耗等进行模拟计算分析。分析不同冷凝温度条件下所设计的再液化系统的运行情况,给出各液货最佳冷凝温度的范围,并对再液化系统进行优化。最后,对装载液货LEG时,复叠式制冷循环高温制冷剂采用R134a和R410A时所取得的不同效果进行分析。     

基于公路桥梁设计中的安全性和耐久性分析研究

在建设公路桥梁时,最重要的是考虑关于安全和耐久两方面的指标。而频繁发生的桥梁安全事故,对于桥梁整体的工程效益有很大的影响,对于交通运输网络的破坏性也是相当明显的。本文将结合具体的工程案例,具体分析桥梁设计中存在的问题,对于提升桥梁设计的安全与耐久性进行探讨。最后提出相应的措施来提升桥梁工程施工质量。希望对以后的类似工程有一定的借鉴作用。     

汽车油耗监测技术的研究分析

本文简要介绍了汽车油耗智能监测系统的各组成部分及其作用,着重讨论了在汽车上安装三种不同的油耗监测设备。通过对实车耗油量与相应行驶里程的分析,以及安装难易度、成本等方面的研究,得出了三种不同油耗监测技术间的差异,对今后汽车油耗监测方式的选择具有一定的参考意义。     

Microscopic structure and property of double-electrode gas metal arc welding of AZ31B magnesium alloy

This paper focuses on the research on double-electrode gas metal arc welding(DE-GMAW) of AZ31 B magnesium alloy sheet with 2 mm thickness. During the welding process, stable hybrid arc of metal inert gas(MIG) and tungsten inert gas(TIG) is employed as welding heat source. Optical and electron microscopes are used to observe the microstructures of the weld joint. X-ray diffraction(XRD) and energy dispersive spectroscopy(EDS) are employed to identify the components in fusion zone. Microhardness is also tested. When the MIG current is 80 A, the perfect weld joint is obtained, though figures of fish scales are observed in all joints in the research. The fusion zone is formed by dendrites, where β-Mg17(Al, Zn)12is dispersed. The hardness in fusion zone and heat affected zone(HAZ) is lower than that in base metal(BM). The average Vickers hardness of fusion zone and HAZ is about 58 and 56 respectively, while the Vickers hardness of BM is about 63.