柔性约束颗粒冲击阻尼技术及应用

本文介绍了柔性约束颗粒击阻尼技术及其减振机理，并将该技术应用于薄密闭腔体壁板振动和内部噪声的控制。实验证明，该技术结构简便，控制频带宽，减振降噪效果显著。     

Free-floating bike sharing: Solving real-life large-scale static rebalancing problems

Free-floating bike sharing (FFBS) is an innovative bike sharing model. FFBS saves on start-up cost, in comparison to station-based bike sharing (SBBS), by avoiding construction of expensive docking stations and kiosk machines. FFBS prevents bike theft and offers significant opportunities for smart management by tracking bikes in real-time with built-in GPS. However, like SBBS, the success of FFBS depends on the efficiency of its rebalancing operations to serve the maximal demand as possible.Bicycle rebalancing refers to the reestablishment of the number of bikes at sites to desired quantities by using a fleet of vehicles transporting the bicycles. Static rebalancing for SBBS is a challenging combinatorial optimization problem. FFBS takes it a step further, with an increase in the scale of the problem. This article is the first effort in a series of studies of FFBS planning and management, tackling static rebalancing with single and multiple vehicles. We present a Novel Mixed Integer Linear Program for solving the Static Complete Rebalancing Problem. The proposed formulation, can not only handle single as well as multiple vehicles, but also allows for multiple visits to a node by the same vehicle. We present a hybrid nested large neighborhood search with variable neighborhood descent algorithm, which is both effective and efficient in solving static complete rebalancing problems for large-scale bike sharing programs.Computational experiments were carried out on the 1 Commodity Pickup and Delivery Traveling Salesman Problem (1-PDTSP) instances used previously in the literature and on three new sets of instances, two (one real-life and one general) based on Share-A-Bull Bikes (SABB) FFBS program recently launched at the Tampa campus of University of South Florida and the other based on Divvy SBBS in Chicago. Computational experiments on the 1-PDTSP instances demonstrate that the proposed algorithm outperforms a tabu search algorithm and is highly competitive with exact algorithms previously reported in the literature for solving static rebalancing problems in SBSS. Computational experiments on the SABB and Divvy instances, demonstrate that the proposed algorithm is able to deal with the increase in scale of the static rebalancing problem pertaining to both FFBS and SBBS, while deriving high-quality solutions in a reasonable amount of CPU time.     

柔性基层沥青路面非线性特性及模量研究

从室内试验和理论分析两方面研究具有碎石上基层的半刚性沥青路面非线性特性和碎石上基层模量合理取值，研究结果表明碎石上基层具有比传统柔性基层高得多的弹性模量，此外碎石上基层非线性有利于重交通对路面的疲劳作用。     

钢轨移动闪光焊接接头软化问题的研究

通过硬度测定、热影响区宏观形貌和微观组织观察,对移动闪光焊接接头软化问题进行了试验研究。研究结果表明,焊接接头软化区与正火热影响区相对应,软化区内的微观组织为粒状珠光体;接头软化是由于正火热处理加热不足所致。同时,提出预防焊接接头软化问题的措施。     

CT技术在沥青胶结颗粒材料内部结构分析中的应用

沥青胶结颗粒材料是由沥青、集料和孔隙组成的特殊复合颗粒材料,被广泛地应用于交通基础设施建设中。其性能既受沥青、集料和孔隙的体积含量影响,也受这些因素的空间分布影响,具有结构性、各向异性及不连续性等特点。本文提出了利用CT技术定量评价沥青胶结颗粒材料内部结构性的方法,通过不同扫描参数下的CT扫描,从CT数和CT图像两方面分析了试件内部的初始结构,着重对比了试件内部不同层面孔隙的分布,为评价沥青胶结颗粒材料初始损伤奠定了基础。     

Kinetics of municipal sewage degradation in EGSB and UASB reactors at 10 ℃

Kinetics of municipal sewage degradation in Expanded Granular Sludge Bed （EGSB） and Up-flow Anaerobic Sludge Blanket （UASB） reactors at 10℃ were investigated via continuous experimental equipments. The results indicated that the whole reaction process can be simulated by the first-order dynamic equation model. Dynamic parameters such as k, Vmax and Ks of UASB in hydrolysis acidification stage were 1.08 d^-1 , 2.8 d^-1 and 372 mg/L comparing to those of 1.18 d^-1 , 3.5 d^-1 and 112 mg/L in the methanogenesis stage respectively. The EGSB＇s k, Vmax and Ks were 2.91 d^-1 , 14.3 d^-1 and 470 mg/L in the hydrolysis acidification stage comparing to those of 1.68 d^-1, 6.6 d^-1 and 103 mg/L in the methanogenesis stage respectively. Comparison of k values of the two stages in UASB and EGSB indicates that hydrolysis acidification stage is the controlling step for the whole reaction process of UASB, while methanogenesis stage is the controlling step in EGSB. Compared with UASB, municipal sewage treatment by EGSB at 10 ℃ can reach the same effluent requirement with lower retention time due to its effluent recirculation.     

汽车尾气净化催化剂的载体研究综述

随着汽车工业的快速发展,全球汽车的拥有量也在逐年的增加。现如今,控制汽车尾气污染物的排放已成为当前社会急需解决的问题。文章主要介绍了催化剂载体的特点、催化剂载体的种类,分析了它们的优缺点以及特点。并且对未来的研究开发方向提出了意见。     

高海拔粒料基层沥青路面性能研究

为解决西藏公路半刚性基层易产生冻害和反射裂缝等病害缺陷,并考虑充分利用西藏当地筑路材料,对高寒高海拔地区粒料柔性基层沥青路面性能进行研究,必将对西藏公路的建设有重要的现实指导意义,使路面结构更经济更耐用,促进筑路技术的发展.通过分析西藏国道318日喀则至拉孜段粒料基层沥青路面试验路的材料组成及检测结果,评价粒料基层在高海拔地区的路用性能.从冻融稳定性、路用承载力两方面分析高海拔粒料基层沥青路面路用性能控制要素.     

柔性基层永久变形试验研究

控制永久变形是柔性基层应用的关键。本文应用MTS试验机,对改良的级配碎石材料试件进行重复加载永久变形试验,通过对不同级配的试件在各应力水平下采集的永久变形量进行综合分析,得到级配碎石材料的永久变形规律。研究表明,级配碎石材料的永久变形随加载次数的增加而增加,主要永久变形在1000次重复加载后完成,级配是永久变形量的重要影响因素。     

橡胶屑粒在稀浆封层和改性稀浆封层中的应用

阐述了橡胶粒特点及使用方法，通过实验证明在稀浆封层或改性稀浆封层中掺和橡胶粒料可增加骨料的耐磨性，粘附性及材料的抗裂性，实现了废旧轮胎的再利用价值。