基于PSTN和IP宽带网的远程监控系统

为提高远程视频监控系统扩展性和灵活性,适应网络带宽的变化,提出了基于PSTN和IP宽带网的监控系统结构模型。使用位率控制精度较高的编码器以适应PSTN(公众交换网的缩写)这种低带宽网络。并采用带宽自适应的策略和方法,实现对网络状况的动态自适应。该系统的编码器采用纯软件实现,能动态地适应网络状况,并能最大限度地利用网络资源。     

Flexible feeder transit route design to enhance service accessibility in urban area

To improve the accessibility of transit system in urban areas, this paper presents a flexible feeder transit routing model that can serve irregular‐shaped networks. By integrating the cost efficiency of fixed‐route transit system and the flexibility of demand responsive transit system, the proposed model is capable of letting operating feeder busses temporarily deviate from their current route so as to serve the reported demand locations. With an objective of minimizing total bus travel time, a new operational mode is then proposed to allow busses to serve passengers on both street sides. In addition, when multiple feeder busses are operating in the target service area, the proposed model can provide an optimal plan to locate the nearest one to response to the demands. A three‐stage solution algorithm is also developed to yield meta‐optimal solutions to the problem in a reasonable amount of time by transforming the problem into a traveling salesman problem. Numerical studies have demonstrated the effectiveness of the proposed model as well as the heuristic solution approach. Copyright © 2015 John Wiley & Sons, Ltd.     

广珠城际铁路双箱单室预制箱梁施工技术研究

针对城际铁路双箱单室箱梁施工的特殊性,研究了该种梁的施工工艺、施工方法和设备选型,解决了该梁型施工生产过程模板拼装、抽拔成孔、混凝土浇筑、小孔道穿束、移梁方式等问题,供类似工程参考.     

Application of the reverse 3D scanning method to evaluate the wear of forging tools divided on two selected areas

This study is focused on tools used in the industrial hot forging process of a front wheel forging (eventually–gear wheel) manufactured for the automotive industry. Four different variants were applied for the tools: 2 die inserts were coated with two different hybrid layers (GN + PVD type), i.e. AlCrTiN and AlCrTiSiN, one insert was only nitrided, and one was pad welded, to improve tool durability. The tool wear was analysed and represented by the material degradation on the working surface, based on the 3D scanning and the material growth of the periodically collected forgings. Additionally, the scanned tools were divided into two areas, in which it was found, based on the reliminary analysis, that various degradation mechanisms are predominant. Microstructural and hardness measurements of the analyzed tools were also performed. Based on the results, it was found that, in the central part of the die insert (area A), thermo-mechanical fatigue and wear occurred, while in the area of the bridge insert (area B), only abrasive wear could be observed. For these areas (A and B), the loss of material was determined separately. In area A for the inserts with hybrid layer GN+AlCrTiSiN and gas nitrided, an intensive increase of wear took place, which was not observed for the pad welded and GN+AlCrTiN layer insert, for which, together with the increase of the forging number, a proportional growth of the loss of material occurred. In area B the weakest results were obtained for the insert with GN+AlCrTiSiN layer, while wear of other die inserts grew similar and proportional.     

基于“聚焦物流”理论的军事运输发展研究

＂聚焦物流＂是美军提出的一种先进物流理念,它要求在准确的地点、时间提供给联合作战各种参战人员和各类装备数量合适的后勤物资供应,它建立在以网络为基础的实时可视化信息系统之上,高效快速地连接战场指挥官和后勤供应机构,通过物流机构和程序的改革,为联合作战提供多功能的后勤保障。＂聚焦物流＂在历次局部战争中得到很好应用,取得良好...     

Finite element modeling of hydrostatic stress distribution in copper dual-damascene interconnects

Hydrostatic stresses of copper dual-damascene interconnects are calculated by a commercial finite element software in this paper. The analytical work is performed to examine the effects of different low-k (k is permittivity) dielectrics, barrier layer and aspect ratio of via on hydrostatic stress distribution in the copper interconnects. The results of calculation indicate that the hydrostatic stresses are highly non-uniform throughout the copper interconnects and the highest tensile hydrostatic stress exists on the top interface of lower level interconnect near via. Both the high coefficient of thermal expansion and the low elastic modulus of the low-k dielectrics and barrier layer can decrease the highest hydrostatic stress on the top interface, which can improve the reliability of the copper interconnects.     

桥面物理除冰雪加热功率与环境因素关系分析

为解决化学融雪剂腐蚀桥梁结构和污染环境的问题，提出桥面敷设加热电缆方式除冰雪技术方案，以30m预应力混凝土T梁桥、沥青混凝土桥面为分析对象，进行了瞬态热分析和稳态热分析，系统研究了在桥面加热升温和稳态融雪节段加热功率与环境温度和环境风速的关系。经分析可知桥面加热过程可分为滞后、升温和稳态三个阶段，得出了一些有意义的结论，可为桥面敷设加热电缆除冰雪设计提供理论参考。     

The Safety Topic of“Oilto Gas”

As a new type of energy,LNG has aroused strong repercussions in the shipping market.The reason for this is that compared with traditional fuel,LNG has certain advantages both in energy conservation and emission reduction and in fuel costs.However,it can not be ignored that as a new type of energy,it has also     

国际海事公约“修行”之路

每一部国际海事公约的出台,都是相关各方不断角力和相互妥协的结果。近年来,随着国际航运业的迅猛发展和技术的不断进步,以及国际社会对海上船舶安全和海洋环境的日益关注,与之相关的国际海事公约不断产生、修正和修订。而这些公约,其效力通过国际海事组织对船旗国履约工作的促进和对港口国监督机制的强化,已形成了一整套确保航行安全和保护海洋环境     

铅酸蓄电池板栅结构的模拟分析

铅酸蓄电池的充放电过程中电流传导主要依靠板栅来完成。板栅的形状、外型尺寸和结构是影响蓄电池性能的重要因素。通过建立铅酸蓄电池单电池的有限元分析模型，分析了板栅的高宽比，极耳的位置，筋条的设计对板栅的电位分布影响，最后得到适当降低板栅的高宽比，极耳的位置向板栅中部移动，增加板栅的竖筋数量有助于降低欧姆压降。