基于LINUX网桥实现隔离网闸技术的应用

网闸是网络安全防护手段之一,传统方法是硬件实现,成本高、控制复杂.本文提出了一种逻辑网闸技术,基于Linux网桥的Ebtables架构,可以在链路层截获数据,并利用逻辑开关实现单向数据通过以及应用层过滤等功能,从而在软件上实现了一个物理隔离网闸的作用.     

Research on subsidence method aided by water injection and its engineering application for the north anchor of Taizhou Bridge

The north anchorage caisson of Taizhou Bridge encountered some difficulties during the sinking process for the large sidewall frictional resistances. To solve this problem, a new concept and method called subsidence method aided by water injection is proposed. Numeral analysis is adopted to simulate the effects of this method for the north anchor of Taizhou Bridge, which confirmed the feasibility and validity. Finally, the method is applied to the north anchor caisson during the caisson sinking procedure and helps the caisson sink and embed to the designed position smoothly.     

坝陵河大桥隧道锚围岩力学特性原位试验研究

为全面认识坝陵河悬索桥西岸隧道锚的受力变形特性及安全稳定性,在分析研究锚碇区地层岩性特点基础上,利用相似性原理设计了与锚碇系统实际受力状态相适应的隧道锚原位模型试验系统,研究了原位试验加载及测试方法.试验成果表明,锚塞体混凝土和岩体在不同岩体条件下呈现出不同的变形特点:当岩体质量较好时,变形基本呈线性变化;当锚塞体周围岩体质量较差时,岩体的非线性变形特征明显.锚塞体与岩体之间的剪切残余变形表明锚塞体和岩体接触面在设计荷载作用下将产生较大的相对滑动.完整性较差岩体中的锚塞体变形远大于完整性较好情况下的锚塞体变形.     

Study on Complexity of Sutong Bridge’s Objectives system and its Meta-Synthesis Management

Objectives define the boundaries of complex engineering system. It is a hard work to determine the specific objectives of a complex engineering system. The objectives system development needs a complicated process, from nix to prototype, and to final definition. The total process will cover the following course: from chaos to well-ordered; from qualitativeness to combination of quantitativeness and qualitativenss, then to qualitativeness to quantitativeness (a recurrent process), expert experience and theoretical science, rationality and sensibility, synthetic analysis and meta-synthetic, routinization and non-routinization. Such process is explicit in phase development yet overlapped; mutually confined yet mutually independent; permeated conflicts yet pregnant in harmony. This article explores the complexity of Sutong bridge’s objectives development and the process of meta-synthesis in the Sutong Bridge engineering.     

Cultivating technical capabilities of enterprises is an important task of the Sutong Bridge project

The paper analyzes existing state of innovation system in the field of public infrastructure construction in China and elaborates on the duty and role of owner in establishment of a technical innovation system with enterprise as the main body following the process of production-education-research. This paper also claims that the key project construction is an important resource to enhance national capability of innovation and accordingly puts forward an effective approach to cultivate the core competitiveness of leading enterprises on the basis of practice in the Sutong Bridge project.     

光纤光栅传感在桥梁工程中的应用

分析了光纤Bragg光栅传感器的基本原理,对目前光纤Bragg光栅传感器在桥梁结构健康监测中的应用情况进行了讨论;探讨了光纤Bragg光栅传感器在研究和应用过程中存在的问题并适当提出了解决方案．     

桥梁大体积混凝土温度裂缝控制与处理

为了使桥梁大体积混凝土温度裂缝得到有效控制,针对桥梁大体积混凝土工程的特点,通过对桥梁大体积混凝土温度裂缝产生的机理分析研究,认为由混凝土内外温差、自身约束和外部约束共同作用产生的温度应力是形成桥梁大体积混凝土温度裂缝的主要原因,并从设计和施工两个方面提出了控制措施。最后,对温度裂缝的处理提出了对策。     

曲率模态理论在桥梁损伤诊断中的应用研究

在曲率模态理论基础上,建立一连续桥梁有限元模型,通过计算研究了桥梁损伤的结构动态响应特点,验证了曲率模态对桥梁结构整体损伤、局部损伤都有较好的敏感性,其结论可为实际公路桥梁损伤诊断提供参考。     

基于角平分线的工程滑移索结构分析方法

针对滑移索结构,提出了一种基于滑轮相邻索单元角平分线的简捷分析方法,解决了其内力和变形求解复杂的难题.具体算法如下:(1)采用固定铰模拟滑轮对索的约束作用,利用无应力长度调整影响矩阵求解角平分线垂直方向约束反力为零时,各子索无应力长度调整量;(2)根据调整后子索线形计算新角平分线的方向角,按照步骤(1)重新计算,重复至索线形(包括角平分线方向角)和内力收敛.基于此算法编制分析程序,通过2~4次迭代即可得到高精度的收敛解,实现滑轮处索力连续性和滑移索总无应力长度恒定的目标.计算示例和工程实例证明了此算法的正确性和高效性.     

图中的生成闭迹

本文得到了如下结果:设G是n≥3级简单图,δ(G)≥2,且G(?)K_(2,n-2))(n为奇数)。若对任意顶点不相交的两边e_0及e_1,d(e_0)+d(e_1)≥2n-2,则G有一个生成闭迹。