预应力孔道灌浆高性能浆体的试验研究

介绍后张预应力孔道灌浆中高性能水泥浆体的配制,并通过相关试验,对灌浆浆体的配比与性能进行了研究。     

路面沥青复合料基于孔隙水压力损坏的实验分析探究

集料-沥青界面强度实验,集料-沥青界面黏合机能影响要素分析,孔隙水压对沥青复合料的损坏原理。本研究经过界面拉拔实验,分析沥青老化、温度和水分等要素对集料-沥青界面黏合机能的影响,探讨车辆载荷作用下孔水压对集料-沥青黏合机能的影响及损坏原理,以为同类沥青复合料路面工程应用提供研究和技术参考。     

Consumer preferences for battery electric vehicles: A choice experimental survey in China

To accelerate the diffusion of battery electric vehicles (BEVs), consumer preferences for different products and policy attributes must be determined. Although previous studies have investigated consumer preferences for some product attributes, including purchase price, operation cost, driving range, and charging time, limited studies have discussed the broader aspects of product attributes, such as battery warranty and depreciation rate. Moreover, market-oriented incentives, including the personal carbon trading (PCT) scheme and the tradable driving credits (TDC) scheme, can theoretically be effective alternatives to expensive purchase subsidies. However, there is a lack of empirical evidence that confirms the influence of these two schemes on BEV adoption. To fill these gaps, we conducted a stated preference choice experimental survey in China and investigated the effect of product attributes, existing policy incentives, and two emerging market-oriented incentives on BEV adoption. Our results reveal that along with the main product attributes, battery warranty has a significant positive effect on inducing mainstream consumers to adopt BEVs while no preference difference occurs among existing policy incentives after purchase subsidies are abolished. For young consumers, almost all incentives that reduce the operation cost (e.g., PCT) or increase convenience (e.g., TDC) can increase their adoption of BEVs. These findings can provide important implications for the government with regard to designing novel incentives and promoting BEV adoption.     

刚架拱桥的检测与承载能力评定

对某缺失资料的刚架拱桥进行了病害调查、无损检测及荷载试验,重点对荷载试验进行了分析.通过对结构加载模拟分析、加载等级与方式的确定、变形和自振频率的实测与分析,表明该桥的承载能力不满足规定的荷载等级,且动力性能较差,需要进行加固维修.此方法为该类桥梁的维护使用和加固改造提供参考.     

一种舰船低频电磁干扰的整改方法与试验研究

为解决声呐系统的低频电磁干扰故障,基于电磁干扰三要素中的辐射耦合路径,提出了一种采用坡莫合金与波纹管相结合的电磁屏蔽整改方法。首先分析了电磁干扰的形成机制以及舰船平台上的常见类型,采用对比试验与电磁环境测试,掌握了此次电磁干扰的耦合路径;通过电磁屏蔽试验以及试验改进,验证了整改方法的可行性。在舰船上实施改进的整改方法,测试结果证明了该方法的有效性,解决了声呐系统的低频电磁干扰故障。     

郁江口及羊栏滩汇流段船舶对会条件改善措施研究

长洲枢纽建成后只能渠化其上游159 km航道,水浅流急的羊栏滩处于水库脱水段。在贵港至梧州二级航道整治工程中对羊栏滩进行了整治,但未根本改善回水末端的郁江口及羊栏滩河段的船舶双向通航条件,按照《航道整治工程技术规范》(JTJ312-2003),加宽后的设计方案航道尺度根本无法满足设计船队的双线通航要求,严重影响航道的通过能力。文章分析了郁江口汇流段及羊栏滩河床形态和通航水流条件的特殊性,通过物理模型试验和自航船模试验相结合的方法,提出并研究了满足船舶对会的工程方案,并对现行规范中弯道双向航道尺度的计算方法提出了建议。     

气田集输管道钢材的选择

针对某气田的气质条件,对气田集输管道材料选择进行了专题研究。分析CO2和Cl-的腐蚀机理,选取了碳钢、不锈钢及双相不锈钢材料进行了气体集输管道腐蚀环境耐蚀模拟试验。实验结果表明：碳钢平均腐蚀速率最快,双相不锈钢腐蚀速率最慢。选取了4种不锈钢进行耐点蚀性能试验与评价。结果显示：马氏体不锈钢2Cr13抗点腐蚀能力最差,25Cr双相不锈钢因其抗点蚀、坑蚀能力强,适宜于某气质腐蚀环境。最后,分别从防腐效果和经济角度论证了采用25Cr双相不锈钢作为内部集输管线的材料优于碳钢＋缓蚀剂。     

车辆协同巡航控制系统设计改进与试验评价

为提高交通流运行的机动性、稳定性,对车辆协同巡航控制(CACC)系统进行了改进设计. 基于经典Newell 模型提出了考虑CACC的改进跟驰模型,分析了所提出的CACC改进跟驰模型的动力学特性,给出了CACC改进跟驰模型的线性稳定性条件,并对由CACC车辆和非CACC车辆组成的非均匀车队的不同无线通讯拓扑结构进行了比较研究. 通过数值试验进一步研究了在起步、刹车和意外事件的情况下,CACC车辆的存在对交通流动力学的影响. 研究结果表明,通过合理设计CACC跟驰系统的模型参数取值后,CACC车辆的存在一方面可以提高交通流运行的机动性与稳定性,另一方面可以使交通出行更加的安全和舒适. 此外,由于不同车队中CACC车辆的无线通讯拓扑结构会影响交通流的机动性与稳定性,对于 CACC车辆的无线通讯拓扑结构应慎重的设计与优化.     

Electric vehicles and residential parking in an urban environment: Results from a stated preference experiment

This paper presents the results of a preference survey of 1545 respondents’ willingness to purchase electric vehicles (EVs) in Philadelphia. We pay particular attention to respondents’ willingness to pay for convenient charging systems and parking spaces. If the value of dedicated parking substantially outweighs the value of convenient charging systems, residential-based on-street charging systems are unlikely to ever be politically palatable. As expected, respondents are generally willing to pay for longer range, shorter charging times, lower operating costs, and shorter parking search times. For a typical respondent, a $100 per month parking charge decreases the odds of purchasing an EV by around 65%. Across mixed logit and latent class models, we find substantial variation in the willingness to pay for EV range, charge time, and ease of parking. Of note, we find two primary classes of respondents with substantially different EV preferences. The first class tends to live in multifamily housing units in central parts of the city and puts a high value on parking search time and the availability of on-street charging stations. The second class, whose members are likelier to be married, wealthy, conservative, and residing in single-family homes in more distant neighborhoods, are willing to pay more for EV range and charge time, but less for parking than the first group. They are also much likelier to consider purchasing EVs at all. We recommend that future research into EV adoption incorporate neighborhood-level features, like parking availability and average trip distances, which vary by neighborhood and almost certainly influence EV adoption.     

舰艇激振和航迹响应实验研究

船舶振动研究在现代船舶上正得到了越来越广泛的应用.内河船一般吃水较小,螺旋桨与船壳的间隙很小,而转速又很高,加上伴流的不均匀,使螺旋桨的激振力加大,对船舶的性能产生很大影响,振动问题更加突出.文章以某舰艇作为主要研究对象,用实验得到的舰艇固有频率和实船振动水平,为作者编制的相近类型船艇振动预报软件提供了检验实例.结果令人满意.