基于底盘测功机的摩托车耐久性和工况排放试验中冷却风机出口风速随距离衰减的研究

摩托车国Ⅲ工况排放测试和耐久性测试中,摩托车要在底盘测功机上跟踪规定的曲线行驶,风机模拟道路行驶中的自然风冷却车辆,速度满足风速等于车速。由于从风机出口断面到摩托车发动机有一定距离,随着距离的增加,出口风速、风量会发生衰减和扩散,这样,到达发动机的风速必然小于车速,致使冷却效果下降,模拟效果不佳,长时间运行还会对发动机、催化转化器产生损害,影响排放结果。     

上中隔壁下双侧壁预锚锭工法在清华园隧道上穿地铁15号线中的应用

为研究新建隧道近距离上穿对既有地铁隧道的变形影响,以京张高铁清华园隧道上穿北京地铁15号线区间隧道为工程背景,提出一种新的施工方法:上中隔壁下双侧壁预锚锭工法,并采用数值模拟和现场实测进行验证,分析隧道施工过程中既有地铁隧道的变形规律。研究结果表明:(1)在侧导洞扩大基础内增加预应力锚索可以有效控制15号线的上浮;(2)上中隔壁下双侧壁预锚锭工法能够保证地铁15号线的安全运营。     

计算机技术在大连港港口设施维修与管理中的应用

在大连港港口设施维修与管理中应用计算机技术,提高了工作效率与管理水平。     

The costs and benefits of a nitrogen emission control area in the Baltic and North Seas

The main purpose of this paper is to analyse the socio-economic justification of implementing a Nitrogen Emission Control Area (NECA), starting 2021, for ships in the Baltic Sea and/or the North Sea and English Channel. We analyse the potential for emission reduction, emission control costs, and monetised benefits following the introduction of a NECA. Costs and benefits are compared for 2030. We compile new data on emission control costs for shipping, use the GAINS model for calculations of emission dispersion, and the Alpha-RiskPoll model for estimating monetary values of health impacts. The model results show that costs to conform to the NO_X regulations of a NECA in the Baltic Sea, North Sea or both sea regions would be 111 (100–123), 181 (157–209), and 230 (195–273) million € per year, respectively. Corresponding benefits from reduced emissions are estimated to be 139 (56–294), 869 (335–1882), and 1007 (392–2177) million € per year, respectively. Calculated benefits surpass costs for most scenarios, but less convincingly for a Baltic Sea NECA. Conforming to the NECA regulations by using Liquefied Natural Gas (LNG) propulsion engines is estimated to give the highest net benefits but also the largest variation (costs: 153 (88–238), benefits: 1556 (49–3795) million €/year). The variations are mainly due to uncertainties in the valuation of avoided fatalities and climate impacts. It is concluded that the NECAs for the Baltic and North Seas can be justified using CBA under all but extreme assumptions.     

中远集团核心信息系统的开发与维护

中远集团核心信息系统是为中国远洋运输（集团）总公司领导和业务部门提供全球范围经贸、航运信息的计算机网络系统。本文将介绍自１９９４年该系统开发和运行以来的四年中,随着计算机信息技术和中远集团全球业务的飞速发展,各项最新计算机信息技术在该系统的开发和维护中的应用     

中俄规范在铁路钢桁梁桥设计中的应用研究

在某国际铁路钢桁梁桥设计过程中,对中、俄两国现行桥梁设计规范计算结果进行对比,同时,采用中国试行极限状态法规范进行试算,比较3种规范的差异性和计算结果的安全储备。中国两种规范设计结果安全储备相差不大,而与俄方规范相比,不同检算项目相差较大,俄方规范对压杆强度控制更为严格,中国规范对疲劳强度控制更为严格。     

国际工程项目风险识别与应对措施

随着我国建筑企业"走出去"战略的实施,承揽的国际工程项目逐渐增多,但同时承担的项目风险也愈来愈多。到底存在哪些风险,如何进行识别,此文从政治、经济、文化、社会和自然环境等方面进行阐述,并对识别出的项目风险如何进行定性和定量分析,根据分析结果采取何种应对措施,控制风险造成的影响和损失进行论述。     

国际工程报价中汇率风险费的估算

在人民币升值的巨大压力下,在确定国际工程投标报价时,汇率风险在风险分析中的地位越发重要,如果在投标阶段不能合理估算汇率风险费用就有可能使项目蒙受经济损失,从而严重影响涉外施工企业的经济效益。此文重点讨论在国际工程投标报价编制阶段,如何对报价组成中的涉汇费用进行分析,并以此为基础估算汇率风险费用。汇率风险费的估算可以有效规避汇率波动对项目造成的经营风险,保持企业经济效益的稳定。     

重庆万豪国际会展大厦风效应试验研究

重庆万豪国际会展大厦是高度达303m的超高层钢结构，其基阶频率仅0．1234Hz，为了准确确定风荷载及其风致响应，对其进行了风致安全性及舒适性评估．采用风洞模型试验方法，对场地大气边界层进行了模拟；通过测压模型风洞试验测量风压系数的分布，并计算静风荷载；用气动弹性模型测量风致响应，包括大厦顶部的位移响应、加速度响应和角速度响应，并计算动风荷载．此外，还讨论了周边环境建筑对其风效应的影响．研究表明，周边建筑环境对大厦的静力和动力风荷载均有较大影响，在设计风速范围内不会产生驰振现象，其顶部加速度和角速度均小于限值，舒适性满足规范要求．     

A game model of international trade,transport costs,invasive species,and protocol compliance

We study the duopolistic interaction between two monopolists located in two different countries who sell an imperfect substitute good in two markets. The traded good is transported between the two nations on ships using solid wood packing materials (SWPMs) and hence the presence of one or more invasive species is a problem. We use a game model to analyze this interaction in three steps. First, we study the benchmark case of autarky or no trade between the two nations. Second, we introduce transport costs and then study the effect of free trade on the profits of the two monopolists. Finally, we suppose that invasive species are present in the SWPMs. This fact requires compliance with an environmental protocol. We model this compliance by increasing the transport costs associated with trade and then demonstrate that a version of the so called Porter hypothesis holds. In other words, we show that compliance with a cost increasing environmental protocol can give rise to higher profits for the two monopolists under consideration.