Impact of road gradient on energy consumption of electric vehicles

We investigate the impact of road gradient on the electricity consumption of electric vehicles (EVs) by combining long-term GPS tracking data with digital elevation map (DEM) data for roads in Aichi prefecture, Japan. Eight regression models are constructed and analysed to compare the differences between linear and logarithmic forms of trip energy consumption, differences between considering the road gradient or not, and differences between considering the fixed effects of EVs or not. By categorizing gradients and assigning a percentage of the trip distance to each category, a significantly better model of electricity consumption can be achieved. The results of this study are a novel contribution toward understanding the challenges and benefits associated with downgrade braking on energy regeneration.     

Measuring energy and environmental efficiency of transportation systems in China based on a parallel DEA approach

Because of China’s rapid economic development, its transportation system has become one of China’s high-energy-consumption and high-pollution-emission sectors. However, little research has been done which pays close attention to China’s transportation system, especially in terms of energy and environmental efficiency evaluation. In this paper, data envelopment analysis (DEA) is applied to measure the energy and environment performance of transportation systems in China with the goal of sustainable development. This paper treats transportation as a parallel system consisting of subsystems for passenger transportation and freight transportation, and extends a parallel DEA approach to evaluate the efficiency of each subsystem. An efficiency decomposition procedure is proposed to obtain the highest achievable subsystem efficiency. Our empirical study on 30 of mainland China’s provincial-level regions shows that most of them have a low efficiency in their transportation system and the two parallel subsystems. There are large efficiency differences between the passenger and freight transportation subsystems. In addition, unbalanced development has occurred in the three large areas of China, with the east having the highest efficiency, followed by central China and then west. Therefore, more measures should be taken to balance and coordinate the development between the three large areas and between the two subsystems within them. Our analysis approach gives data for determining effective measures.     

动车组显控界面字体大小对司机识别效率的影响

从动车组的列车运行监控及记录装置(LKJ)和列车超速防护系统(ATP)显控界面上,选取分布频率最高的6,9,12和15画且左右结构的4组常见汉字,以正确的反应时间为识别效率指标,测试这4组汉字的结构复杂度和字体面积对动车组司机识别效率的影响.首先采用因子方差分析法分析司机在识别这4组不同结构复杂度常见汉字时反应时间的差异;然后采用对数函数对测试数据进行回归分析,得到字体面积与识别效率间的定量关系式;最后以满足正常识读速度和反应操作耗时为限制条件得到对应这4组常见汉字字体面积的最小阈值分别为26,28,22和20mm2.     

A Practical Adaptive TuCM Scheme for Rayleigh Flat Fading Channels

IntroductionAs stated in Ref.[1 ],if the channel state isknown atthe transmitter,then channel capacity isachieved by adapting the transmit power,data rateand coding scheme relative to this fade state.Based on those results,an uncoded adaptive modu-lation was proposed[2 ] .This adaptive modulation is1 7d B more power efficientthan non- adaptive mod-ulation in fading.Combining trellis coded modula-tion ( TCM) with adaptive modulation,an adaptivecoded modulation was studied[3 ] .The results sh…     

混凝土灌注桩基础桩底压浆工艺的应用与发展

通过对混凝土灌注桩基础桩底压浆工艺的适用条件、原理、施工工艺及技术特点的详细阐述和经济效益分析 ,反映了该项工艺的诸多优越性和较高的推广价值     

铁路远动信道信息传输差错控制特性分析

本文就电气化铁道牵引变电所远动监控系统中信道的信息传输问题，在其可靠性，吞吐率及最佳码长等方面进行了分析，并分别推导出其数学模型，它直接关系到运动系统信息传输协议的制定及通信方式的选择。     

基于最大输出功率的高效钢轨交流闪光焊工艺

针对目前国内大量使用的К型交流钢轨闪光焊机,根据焊接主回路等效电路建立了最大功率输出和高效焊接控制的数学模型,编制了过程控制程序.采用К900钢轨焊机设置不同的高压阶段焊接电流进行试验,以测量在相同烧化量时的高压阶段时间.试验表明,当高压阶段焊接电流接近设备最大功率输出的焊接电流时,高压阶段焊接时间较短.在高压阶段和低压阶段的前期,采用基于最大输出功率的高效焊接控制模型,可以快速加热钢轨,缩短焊接时间,提高焊接生产率.     

磨料水射流提高加工工程陶瓷效率试验研究

工程陶瓷材料是一种经过高温烧结而形成的无机非金属材料，具有耐高温、耐腐蚀、抗磨损及抗热冲击等优点，但由于它硬度高、脆性大，大多数陶瓷材料不导电，用传统的机械加工方法难以加工，使用范围受到限制。近年来，高压磨料水射流这种新兴的加工工程陶瓷的方法越来越受到人们的重视，选择不同的工艺参数，作了大量试验，研究分析了各工艺参数对加工效率的影响，给出了一种优选工艺参数的方法。     

改善航道条件促进沿江经济发展

本文在分析长江航运发展现状的基础上,阐述了影响长江航道,尤其是江苏段航道发展的因素,提出了提高长江下游江苏段航道通航效率的对策。