集料毛体积相对密度测试方法研究

文章分析了粗集料试样烘干质量对于毛体积相对密度测试值以及沥青混合料最佳沥青用量的影响．并提出了测试方法的改进措施;分析采用吻合表观相对密度值的方法,以保证细集料毛体积相对密度测试结果的准确可靠。     

论提高机械制图课程的教学质量

文中从提高教师的素质、优化课程结构、加强实践教学、改进教学方法、培养学习兴趣等方面,论述了《机械制图》课程改革的可行性操作方法。     

预应力混凝土梁板质量事故分析

通过对预应力混凝土梁、板在预制、安装、堆放和移运等过程中容易发生的质量问题进行分析,通过有关实例加以说明解释,并且提出一些注意事项和解决措施,以便提高预应力混凝土梁、板预制、安装的施工质量和技术水平。     

高墩T型刚构桥主桥设计及质量控制

本文以武广客运专线上黄土湾大桥——55m＋65m预应力混凝土T型刚构桥的设计资料为例,介绍了预应力混凝土T型刚构桥的构造,结构计算特点以及纵、横向预应力设计,为同类型桥梁设计提供参考。     

水泥稳定碎石路面基层施工技木的探讨

水泥稳定碎石基层在高等级公路路面工程中已越来越得到广泛的应用。针对水泥稳定碎石基层的施工准备、混合料拌制、运输、摊铺、碾压、养生等施工全过程进行研讨，分析影响施工质量的因素，提出控制质量的施工方法及技术措施．对防止路面的早期损坏具有重要的意义。     

A Distributed and adaptive framework for provisioning QoS in IPv6 networks

A distributed and adaptive framework （DAF） was proposed for provisioning quality of service （QoS） in IPv6 network. In DAF, per-flow admission control and resource reservation, in conjunction with a new IPv6 flow label mechanism, can be performed instantaneously in a fully distributed and independent fashion at the edge of network without hop-by-hop signaling. The flow label helps in resource reservation and packets forwarding for aggregated traffic on an edge-to-edge path basis. In addition, a bounded directional probing technique for DAF was designed to reconfigure resource reservation adaptively between every pair of edge router for aggregated traffic according to the fluctuation of its traffic load. The simulation results show that DAF provides QoS guarantees to individual flows with minimal overhead, as well as keeping the scalability characteristic like DiffServ.     

桥梁工程混凝土质量管理方法

简要分析影响桥梁混凝土质量的主要因素，总结桥梁混凝土质量管理方法。研究表明，保证混凝土的质量需要合理划分施工标段，严格监理，严格遵守配比和相关流程，通过第三方进行质量检测。     

钢筋混凝土质量通病及防治措施

随着我国社会经济的高速发展,交通运输需求不断增强,我国的高速公路道路建设行业也迎来了良好的发展机遇,同时也出现一些问题,钢筋混凝土施工质量的控制便成了重中之重。针对国内高速公路道路混凝土施工中的相关质量问题进行分析,提出有效的控制技术措施,供同行参考和借鉴。     

新型局域共振橡胶减振垫振动传递特性测试分析

为了研究一种应用于浮置板轨道结构的新型橡胶减振垫的振动传递特性,对比某基于局域共振新型减振垫与普通橡胶减振垫的减振性能,研究预压质量与激振加速度对振动传递特性的影响,对新型橡胶减振垫进行刚度试验与振动传递特性试验,测试其在30~200 Hz频率下的传递特性,试验过程中采用不同的预压质量与激振加速度,振动传递特性测试采用加速度激振的方法,以加速度传递率作为减振垫振动传递特性的评价指标。结果表明:新型减振垫加速度传递率更小,减振效果更好,最大可以减小10 dB左右;减振垫上方预压质量对振动传递特性有较大影响,预压质量越大,加速度传递率越大,减振效果越差;减振垫的刚度对其振动传递特性有一定的影响,激振的加速度幅值对加速度传递率影响较小。     

Non-exhaust particle emissions under various driving conditions: Implications for sustainable mobility

Non-exhaust particle (NEP) emissions from road traffic contribute significantly to Particulate Matter (PM) pollution in urban areas. The primary objective herein is to develop the knowledge required to move toward more sustainable mobility. NEP emissions are studied by means of complementary experiments on chassis dynamometers, on test tracks and at the roadside. Laboratory tests demonstrate that brake wear particles (BWP) emissions can change with braking force and frequency. A brake pad temperature threshold exists, above which the rate of ultrafine particle emissions is quite high. Below this threshold, the BWP emissions are dominant in the accumulation and coarse modes. Test track measurements have demonstrated that tire-road contact particle (TRCP) emissions considerably modify the atmospheric PM background especially for the supermicron fraction. Their number size distribution highlighted an ultrafine and accumulation modes centered at about 40 nm and 200 nm, respectively. The TRCP level increases with vehicle speed and during the acceleration and deceleration phases. Roadside measurements in the urban environment confirm the presence of NEP in significant proportions, in both the accumulation and coarse modes. The chemical composition of NEP differs depending on the size mode: BWP mainly stem from the degradation of brake pad lining materials, while TRCP are a mixture of tire tread wear and re-suspended dust. The presence of Fe-rich particles nevertheless serves as a good indicator of the NEP contribution to PM at the roadside. Lastly, in considering the parameters influencing NEP emissions, a series of recommendations are offered in order to achieve a more sustainable mobility.