许沟特大桥主拱结构徐变与收缩影响研究

针对许沟特大桥主跨220 m钢筋混凝土等截面悬链线箱形无铰拱,主拱圈采用支架上分层分段现浇施工方法属国内首创,混凝土徐变与收缩对主拱受力影响很大。通过建立合理的徐变与收缩数学模型和采用数值及有限元分析方法,研究了各加载工况下混凝土徐变、收缩对主拱主控截面内力与变形以及截面应力重分布的影响,分析了混凝土收缩对主拱圈分层浇注自应力的影响。研究结果为大桥预拱度设置及分段分层浇注方案制定和时间间隔控制提供了可靠的理论依据,并为同类桥梁的设计、施工提供借鉴指导。     

Impacts of trade liberalization on Chinese economy with Belt and Road initiative

China has been continuously implementing the open-door policy for past 15 years ever since it joined the World Trade Organization, which escalated international trade and demand for shipping. Compared with the other major importing countries in the world, China’s importing tariff is relatively low. Under the Belt and Road initiatives, more Free Trade Agreements to be concluded and more Free Trade Zones to be established, it is expected that the effective import tariff rate may continue to decrease in the future. This study analyses the impact of further reduction in Chinese import tariff rate on major economic indicators using a computable general equilibrium (CGE) model and based on the Chinese macro-economic data of 2012. The model results show that, with a balanced international payment, such a reduction can increase GDP, resident consumption, both imports and exports, and reduce GDP price, trade surplus, and government revenue. The results ease the concern that further import tariff reduction may harm the domestic production. Rather, it points out that there are still rooms to improve national economy and increase the consumer utility by trade liberation.     

影响轿车乘降性能主要因素

针对轿车在总布置基本尺寸及硬点的确认过程中,如何确保设计轿车具有较好的乘降陛能（出入车方便性）,文章从驾驶员和乘员与汽车门洞、座椅、方向盘、B柱、门槛及车门等方面阐述了进出车厢方便性能的主要因素及相关尺寸的设计控制方法,提出了一些供设计者参考的设计经验数值,指出任何尺寸定义都不能独立于其他尺寸或硬点的定义之外,要考虑造型、结构、安全及性能等方面要求。     

脉搏血氧仪定标曲线的研究

为解决脉搏血氧仪经验定标曲线低血氧饱和度段数据极难获取的问题。同时避免传统方法对受试者的健康损害 ,选取满足条件的 1 84例成年肺部疾病患者 ,由血气分析仪测得的 Sa O2值与经过改造的脉搏血氧仪同步得的 R/IR值构成数据点 ,建立脉搏血氧仪临床定标准曲线同。经实验验证 ,使用该定标曲线的脉搏血氧仪与国外名牌脉搏血氧仪以及血气分析仪同时进行人体实测 ,结果基本相同。表明本文采用的方法具有可行性和实用性。     

国企呼唤创新求变的人力资源管理

现代企业的生存与发展受众多因素影响和制约。其中,最重要也是最根本的因素就是企业的劳动者——人力资源,他们是企业所有资源中最宝贵的,因而必须对其进行有效管理。但是在实际操作中,许多企业更关心的可能是它的资金和市场问题,人力资源管理常常为其所忽视。然而恰恰可能是人力资源的瓶颈阻碍了企业的进一步发展。本文就此提出国企中人力资源管理的几点建议。     

深层水泥搅拌桩结合地连墙在码头中的应用

在软弱地基上修建板桩码头，采用地连墙替代板桩结构，同时考虑到码头作业平台荷载较大的实际情况．应用深搅桩进行地基处理，将地连墙与搅拌桩有机组合形成一个整体，以维持码头整体稳定。该结构型式开辟了码头型式的一条新思路，具有一定的社会经济效益。     

浮动平均值在大变形隧道定额测定与分析中的应用

近年来,国内外对大变形段隧道在设计、施工技术方面的研究取得了一定的成果,例如兰渝、拉林等铁路项目均对高地应力大变形进行了研究,铁建设[2007]155号文也针对施工降效明确了定额增加幅度系数。但是在定额测定的过程中,由于隧道工程施工的复杂性和综合性,所需的施工组织模型原始现场数据数量极大,算数平均等方法求解的消耗量会因施工环境变化等难以避免的因素,存在偏差或异常。本文介绍了R语言编程计算浮动平均值的方法,并运用研究成果,对写实数据进行二次处理和优化,有效提高了数据的准确性和稳定性。     

如何避免GSM-R无线通信系统对机场电磁干扰

以拟建合湛高速铁路经过遂溪机场的线路方案为例,对Longley-Rice不规则地形信道模型进行了简要介绍,仿真分析了该模型在不同传输距离和置信区间下信号的衰落情况。现场实测数据验证了Longley-Rice信道模型的准确性和合理性。结合仿真和实测结果,提出了GSM-R无线覆盖的解决方案,并且为铁路选线方案的优化提供了技术支撑。     

CORS在公路测量中的应用

随着连续运行GPS参考站技术的不断发展,网络RTK的优势不断体现出来。文章结合内蒙古全球导航卫星连续运行参考站综合服务系统网（NMGCORS）的建设,陈述了网络RTK的原理及Trimble R8 GPS如何进行网络RTK设置,希望对相关技术人员有参考作用。     

Does uncertainty make cost-benefit analyses pointless?

Cost-benefit analysis (CBA) is widely used in public decision making on infrastructure investments. However, the demand forecasts, cost estimates, benefit valuations and effect assessments that are conducted as part of CBAs are all subject to various degrees of uncertainty. The question is to what extent CBAs, given such uncertainties, are still useful as a way to prioritize between infrastructure investments, or put differently, how robust the policy conclusions of CBA are with respect to uncertainties. Using simulations based on real data on national infrastructure plans in Sweden and Norway, we study how investment selection and total realized benefits change when decisions are based on CBA assessments subject to several different types of uncertainty. Our results indicate that realized benefits and investment selection are surprisingly insensitive to all studied types of uncertainty, even for high levels of uncertainty. The two types of uncertainty that affect results the most are uncertainties about investment cost and transport demand. Provided that decisions are based on CBA outcomes, reducing uncertainty is still worthwhile, however, because of the huge sums at stake. Even moderate reductions of uncertainties about unit values, investment costs, future demand and project effects may increase the realized benefits infrastructure investment plans by tens or hundreds of million euros. We conclude that, despite the many types of uncertainties, CBA is able to fairly consistently separate the wheat from the chaff and hence contribute to substantially improved infrastructure decisions.