公路养护成本控制及防护方案决策影响因素分析

鉴于公路养护的重要性,提出为了更好地促进我国公路管理事业的发展,必须加强对于公路养护的重视程度,有效控制公路的养护成本,并选择最适合公路养护的方案决策,这样才能使我国的公路养护事业逐渐发展完善起来。     

台风的预防预控

防抗台风是海事部门的重点工作之一，只有采取有效的针对性措施才能最大限度地减小损失。     

Public transit subsidies, output effect and total factor productivity

This paper extends previous works on total factor productivity decomposition when firms receive both operating and capital subsidies. It shows that previous works considered either the lump-sum or substitution effects of these subsidies but not together. Using constrained cost minimization as the framework it offers formal proofs to show that cost increases are inevitable if the total effects of the subsidies are considered, and that total factor productivity growth results from increasing amounts of subsidies under economies of scale and in the absence of technical change. Applications of the decomposition equations derived to a sample of transit systems finds near constant returns to scale and negative contributions of these subsidies to total factor productivity growth. Technical change reverses this decline and results in total factor productivity growth. Further, it finds that the lump-sum effects of the subsidies reduce total factor productivity more than does the substitution effect.     

天津富民桥锚碇及箱梁过渡段构造施工

天津富民桥主桥为单塔空间索面自锚式悬索桥结构,介绍该桥主跨自锚式锚碇、边跨重力式锚碇及钢-混凝土过渡段的施工特点以及根据现场实际情况采取的有效措施.     

Technical Note: Force Control in Electrohydraulic Active Suspensions Revisited

The inner loop control for the actuator force can be quite simply compensated by means of a correction term to the desired force signal at the input. The correction requires only a measurement of the actuator piston velocity and is employed to cancel the loop disturbance caused by the oil flow to the actuator. Although an additional time constant is introduced by the integration in the inner loop force control, the overall performance is nevertheless quite close to that of an ideal optimal system.     

沥青混凝土热铺层厚度测量仪设计

针对在公路养护与沥青混凝土路面摊铺过程中,沥青混凝土的厚度控制对施工成本、路面平整度、路面质量及验收结果的影响,设计了一种能够精确测量沥青混凝土热铺层厚度的实用新型厚度测量仪,克服了目前公路工程施工中沥青混凝土热铺层厚度测量技术中的缺点与不足     

桥梁抗风控制及设计探讨

桥梁结构的抗风性是影响桥梁设计和施工其中一个重要因素.对桥梁抗风设计和桥梁风致振动控制进行探讨并提出相应的措施,可为桥梁抗风工作提供参考.     

中日高速公路养护作业控制区对比研究

以日本阪神高速公路养护作业控制区的实际布置为例,与我国JTG H30-2015《公路养护安全作业规程》中的相关规定进行了详细对比分析,从而得出中日两国之间在高速公路养护作业控制区布置方面的差异,对指导我国高速公路养护作业控制区划分及其相关研究有一定的参考价值。     

内河航道智能微型测量船的设计与应用研究

传统的航道水深测量方式，测量成本较高，而且，很多情况下，由于水浅等原因，较大的常规测量船不能到达，而难以测量．文中介绍了航道水深测量遥控测量船的设计原理和应用情况．遥控船上安装有测量系统，能够实现远程手动遥控测量和按预定航线自动导航测量．该船吃水浅、航速快、稳性好、遥控距离远，有2套动力系统，可远程自由切换，安全性高．2011年投入使用以来，取得了较好的效果．     

Modelling and control of a new differential steering concept

This paper presents a new steer-by-wire concept using an all-wheel drive vehicle layout with in-wheel motors while completely omitting the application of any dedicated steering device. Steering is based on the so-called differential steering principle which generates the necessary steering moment about the kingpins by a traction force difference between left and right sides of the vehicle. In order to investigate the behaviour of the vehicle and to design the underlying control algorithms, a planar vehicle model is presented, where the vehicle is described as constrained non-holonomic system requiring a special treatment. A state feedback linear controller for controlling of the lateral dynamics of the vehicle at higher speeds and a simple PI angle controller for low-speed manoeuvring are developed. The resulting behaviour of the system is investigated by various simulation experiments demonstrating a comparable steering performance of the new steering concept as that of conventional passenger cars.