能效设计指数EEDI功率曲线的直接计算方法

船舶能效规则强制生效后,所有适用船舶必须满足Attained EEDI≤Requied EEDI的条件,因此准确估算或预报功率曲线从而计算得到Attained EEDI将对适用船型具有极为重要的意义。根据国内外关于功率-转速-航速预报的最新进展,依据螺旋桨敞水性能图谱,采用KT/J^2系数,给出了功率曲线的直接计算方法,经实际算例验证,该方法相对传统的间接计算方法更为清晰简便,且结果准确可靠。     

抗紫外老化剂对沥青性能的影响

为解决南方湿热地区沥青路面受紫外光老化影响问题,利用紫外老化环境箱和动态剪切流变仪研究老化时间和受阻胺类抗紫外老化卉l】（GW一944）对沥青高温动态力学性能、低温和疲劳性能的影响。试验结果表明：强紫外光降低了沥青疲劳性能和低温性能,改善了抗车辙性能,且随老化时间延长而加剧;受阻胺类抗紫外老化剂（GW-944）能较好地对SBS改性沥青进行抗老化性能改善,且对其性能改善存在合适的掺量范围,适宜掺量为0．5％,而对基质沥青性能改善并不适用。研究成果为沥青路面有效防治紫外光老化提供了技术依据。     

圆砾泥岩复合地层泥水盾构下穿建筑物

泥水盾构机在圆砾、泥岩复合地层中掘进时,容易发生泥浆管、盾构机前仓进渣口堵塞(堵管堵仓)的现象,引起前仓压力波动,施工风险急剧增加。通过对盾构泥浆性能进行优化,降低堵管堵仓发生的概率;通过设定合理的前仓压力,优化掘进参数,保证开挖面的稳定,有效控制建筑物变形;之后选取正确的材料和施工工艺,利用同步注浆和二次补浆,有效控制地层和建筑物后续变形;同时利用信息化管理技术,采用自动化监测和信息化管理平台,使地下与地上联动,及时调整施工参数,更加有效地控制了建筑物沉降,为盾构机安全顺利下穿建筑物提供有力保障。     

国产轻轨车辆的主要技术参数特点

国产轻轨车辆采用铰接式、短轴距转向架及大截面铝合金车体等先进技术,实现了3、4、5辆车灵活编组及单辆车的双向运行。简要介绍车体、转向架、主电路、辅助电源、制动等主要系统和部件的特点及其技术参数。     

Impact of inerter nonlinearities on vehicle suspension control

This paper discusses the nonlinear properties of inerters and their impact on vehicle suspension control. The inerter was recently introduced as an ideal mechanical two-terminal element, which is a substitute for the mass element, where the applied force is proportional to the relative acceleration across the terminals. Until now, ideal inerters have been applied to vehicle, motorcycle and train suspension systems, in which significant performance improvement was achieved. However, due to the mechanical construction, some nonlinear properties of the existing mechanical models of inerters are noted. This paper investigates the inerter nonlinearities, including friction, backlash and the elastic effect, and their influence on vehicle suspension performance. A testing platform is also built to verify the nonlinear properties of the inerter model.     

The effects of wheelset driving system suspension parameters on the re-adhesion performance of locomotives

In this study, in order to examine the effects of a wheelset driving system suspension parameters on the re-adhesion performance of locomotives, the stick–slip vibration was analysed according to theoretical and simulation analysis. The decrease of the slip rate vibration amplitude improved the stability of the stick–slip vibration and the re-adhesion performance of locomotives. Increasing the longitudinal guide stiffness of the wheelset and the motor suspension stiffness were proposed as effective measures to improve the re-adhesion performance of locomotives. These results showed that the dynamic slip rate was inversely proportional to the series result of the square root of the longitudinal guide and motor suspension stiffness. The larger the motor suspension stiffness was, the smaller the required longitudinal guidance stiffness was at the same re-adhesion time once the wheel slip occurred, and vice versa. The simulation results proved that the re-adhesion time of the locomotive was approximately proportional to amplitude of the dynamic slip rate. When the stick–slip vibration occurred, the rotary and the longitudinal vibrations of the wheelset were coupled, which was confirmed by train's field tests.     

Estimation of delay variability at signalized intersections for urban arterial performance evaluation

Urban arterial performance evaluation has been broadly studied, with the major focus on average travel time estimation. However, in view of the stochastic nature of interrupted flow, the ability to capture the characteristics of travel time variability has become a critical step in determining arterial level of service (LOS). This article first presents a stochastic approach that integrates classic cumulative curves and probability theories in order to investigate delay variability at signalized intersections, as a dominant part of the link travel time variability. This serves as a basis for arterial travel time estimation, which can be obtained through a convolution of individual link travel time distributions. The proposed approach is then applied in the estimation of travel time along one arterial in Shanghai, China, with abundant automatic vehicle identification (AVI) data sources. The travel time variability is evaluated thoroughly at 30-min intervals, with promising results achieved in comparison to the field measurements. In addition, the estimated travel time distributions are utilized to illustrate the probability of multiple LOS ranges, namely, reliability LOS. The results provide insights into how we might achieve a more reliable and informative understanding of arterial performance.     

新型沙漏式FPSO的浮体外形参数对水动力性能的影响

为了解决传统船型和已有圆柱筒状FPSO的性能局限,论文提出了一种具有沙漏型浮式主体的新概念FPSO。根据所研发的新型沙漏式浮体模型,确定了能够反映浮体几何形状、FPSO基本功能和水动力性能的5个相互独立的外形参数。然后,采用基于频域势流理论的边界元数值模拟方法研究了新型沙漏式浮体在波浪中的运动响应,并且定性分析了不同浮体外形参数(下倾角、水线面半径等)对浮体水动力性能的影响,得到一些有意义的结论,以期能够为新型沙漏式FPSO的主浮体外形设计提供参考依据和准则。     

海水电池用导电聚苯胺正极性能的研究

研究导电聚苯胺作为海水电池正极性能,通过与镁合金负极组成电池进行电性能实验,并与Mg/氯化银电池进行性能比较。结果表明导电聚苯胺作为海水电池正极具有较好的放电性能,其工作电压可达到1.2~1.35 V;导电聚苯胺自身的导电性使其在激活初始时期能在短时间内耐受较大电流;增加导电添加剂和减薄电极厚度后可增加Mg/导电聚苯胺电池的电压稳定时间;导电聚苯胺与聚四氟乙烯溶液(5%wt)比例在3.7:1~4:1时有利于正极成型。     

Numerical Investigations on the Aerodynamic Performance of Wind Turbine：Downwind Versus Upwind Configuration

Although the upwind configuration is more popular in the field of wind energy, the downwind one is a promising type for the offshore wind energy due to its special advantages. Different configurations ...