汽车用闪光继电器的无线电骚扰抑制技术

为适应国家推出的GB186 55—2002《用于保护车载接收机的无线电骚扰特性的限值和检测方法》,在分析汽车用闪光继电器工作原理及产生无线电骚扰原因的基础上,设计了2种解决方案。根据这2种方案的工作原理,在相同的条件下分别进行了电磁干扰噪声的测试。得出方案2完全符合要求,指出使用数字电路可以很好地解决开关电路引起的电磁兼容问题。     

574.8 km/h世界高速列车速度新记录的启示

分析法国创造574.8km/h高速列车最高试验速度记录的技术手段。阐述先进的技术标准体系是法国高速领域不断创新的技术支撑。展望世界高速列车技术的发展方向。     

基于自抗扰控制的空间矢量直接转矩控制策略研究

针对三相异步电动机这个非线性、强耦合控制对象,利用自抗扰控制对不确定对象的适应性和对系统未建模动态及参数摄动的鲁棒性,提出基于自抗扰控制的空间矢量直接转矩控制策略,借鉴自抗扰控制思想,引入不连续投影算子加以修正,解决了标准扩张状态观测器对时变外扰无法保证观测误差有界的问题,设计了速度环和磁链环控制器,并通过Lyapunov稳定性理论分析了其稳定性,得出可定量设计的参数化收敛边界描述。仿真结果表明,文中提出的控制策略能有效改善系统对时变扰动及未建模动态的鲁棒性,具有一定的理论和实践价值。     

车轮速度传感器的构造与维护

车轮速度传感器的作用是将车轮的转变为电压信号,输送给电子控制系统（ＥＣＵ）,并发出相应的指令。介绍了车轮速度传感器的构造、工作原理、维护与检测。     

大型油船航速估算方法

对现有的船舶航速估算方法分析比较，提出了大型油船的航速估算方法。其中有效功率估算是根据上海船研所肥大船系试验图谱和实船试验资料经分析、修正得出，与荷兰Ｈｏｌｔｒｏｐ法、大连造船厂法比较，本文方法均方差最小，估算值与试验值最接近；自航因子估算以ＳＳＰＡ大油轮系列自航试验资料为基础，用上海船研所大量肥大船模型自航试验数据修正得出。     

摩托车减震器阻力—速度特性曲线构成(1)

通过对产生阻力结构的分析,建立了复原、压缩行程的数学模型。对3种阻力一速度特性曲线的研究,依据努伯利流量连续定理,推导出阻力的基本公式。这些公式对研究阻力产生的结构,以及运动油的流向具有重要的意义。     

某28000DWT散货船EEDI分析研究

文章针对某28 000DWT散货船的船型尺度、主要性能、基本布置以及内部结构等内容提出了散货船EEDI这一概念,并提出了一系列的改进措施以提高散货船EEDI。     

Contrasting the direct use of data from traffic radars and video-cameras with traffic simulation in the estimation of road emissions and PM hotspot analysis

This study investigates the effect of traffic volume and speed data on the simulation of vehicle emissions and hotspot analysis. Data from a microwave radar and video cameras were first used directly for emission modelling. They were then used as input to a traffic simulation model whereby vehicle drive cycles were extracted to estimate emissions. To reach this objective, hourly traffic data were collected from three periods including morning peak (6–9 am), midday (11–2 pm), and afternoon peak (3–6 pm) on a weekday (June 23, 2016) along a high-volume corridor in Toronto, Canada. Traffic volumes were detected by a single radar and two video cameras operated by the Southern Ontario Centre for Atmospheric Aerosol Research. Traffic volume and composition derived from the radar had lower accuracy than the video camera data and the radar performance varied by lane exhibiting poorer performance in the remote lanes. Radar speeds collected at a single point on the corridor had higher variability than simulated traffic speeds, and average speeds were closer after model calibration. Traffic emissions of nitrogen oxides (NOx) and particulate matter (PM₁₀ and PM_2.5) were estimated using radar data as well as using simulated traffic based on various speed aggregation methods. Our results illustrate the range of emission estimates (NO_x: 4.0–27.0 g; PM₁₀: 0.3–4.8 g; PM_2.5: 0.2–1.3 g) for the corridor. The estimates based on radar speeds were at least three times lower than emissions derived from simulated vehicle trajectories. Finally, the PM₁₀ and PM_2.5 near-road concentrations derived from emissions based on simulated speeds were two or three times higher than concentrations based on emissions derived using radar data. Our findings are relevant for project-level emission inventories and PM hot-spot analysis; caution must be exercised when using raw radar data for emission modeling purposes.     

Dynamic optimization of ship energy efficiency considering time-varying environmental factors

Nowadays, optimization of ship energy efficiency attracts increasing attention in order to meet the requirement for energy conservation and emission reduction. Ship operation energy efficiency is significantly influenced by environmental factors such as wind speed and direction, water speed and depth. Owing to inherent time-variety and uncertainty associated with these various factors, it is very difficult to determine optimal sailing speeds accurately for different legs of the whole route using traditional static optimization methods, especially when the weather conditions change frequently over the length of a ship route. Therefore, in this paper, a novel dynamic optimization method adopting the model predictive control (MPC) strategy is proposed to optimize ship energy efficiency accounting for these time-varying environmental factors. Firstly, the dynamic optimization model of ship energy efficiency considering time-varying environmental factors and the nonlinear system model of ship energy efficiency are established. On this basis, the control algorithm and controller for the dynamic optimization of ship energy efficiency (DOSEE) are designed. Finally, a case study is carried out to demonstrate the validity of this optimization method. The results indicate that the optimal sailing speeds at different time steps could be determined through the dynamic optimization method. This method can improve ship energy efficiency and reduce CO₂ emissions effectively.     

On two speed optimization problems for ships that sail in and out of emission control areas

This paper deals with two speed optimization problems for ships that sail in and out of Emission Control Areas (ECAs) with strict limits on sulfur emissions. For ships crossing in and out of ECAs, such as deep-sea vessels, one of the common options for complying with these limits is to burn heavy fuel oil (HFO) outside the ECA and switch to low-sulfur fuel such as marine gas oil (MGO) inside the ECA. As the prices of these two fuels are generally very different, so may be the speeds that the ship will sail at outside and inside the ECA. The first optimization problem examined by the paper considers an extension of the model of Ronen (1982) in which ship speeds both inside and outside the ECA are optimized. The second problem is called the ECA refraction problem, due to its conceptual similarity with the refraction problem when light travels across two different media, and also involves optimizing the point at which the ship crosses the ECA boundary. In both cases the objective of the problem is to maximize daily profit. In addition to mathematical formulations, examples and sensitivity analyses are presented for both problems.