制氢方法的评价及对氢燃料电池汽车推广的影响研究

氢燃料电池汽车（FCV）是未来交通运输的理想解决方案,由于其在使用过程中仅消耗氢气,寻找对资源、能源和环境影响最小的氢气来源,对交通运输行业的节能减排具有重要意义。分析和评估了4种不同的制氢方法,通过建立FCV燃料循环的全生命周期评估数学模型,并与GaBi软件的基础数据库相结合,实现对FCV的全生命周期评价。选择丰田MIRAI FCV作为实例对象,对所建立模型的有效性进行验证。基于建立的评价模型,对FCV生命周期的各个阶段进行评价,探讨不同制氢方法对资源、能源和环境的影响,研究中国电力结构和制氢效率改进对电解水制氢法的积极作用,分析了以不同清洁能源作为电力来源时对电解水制氢法的影响程度。在对中国的人口、能源分布情况和能源结构变化趋势进行分析后,结合建立的清洁能源电价预测数学模型,提出了短期内适合推广FCV的区域,明确了考虑环境成本时的各区域推荐的制氢方法或清洁能源发电类型,给出了考虑经济成本时的各区域在当前和未来30年内推荐的清洁能源发电类型。通过所建立的生命周期评价模型和清洁能源电价预测模型,确定当前阶段的最佳制氢方法,发现了中国当前电力结构存在的问题,明确未来中国各地区能源结构发展的方向。研究结果表明：只有以清洁能源发电作为电力来源时,电解水制氢法才是未来大规模制氢的理想方案,清洁能源使用优先级顺序为核能、水电、风能;人口密度小于150人·km^-2的地区（除中心城市外）未来一段时间内不应大面积推广FCV,推广的重点应该在中国的东南部地区。     

基于电力电子变流技术的风力能源变换系统

利用电力电子变流技术的风力发电系统是风力能源系统中一个发展迅速的分支,基于逆变技术和先进控制技术的系统可以使风机在不同的风速下运行在最大功率状态.文章综述了该领域电力电子变流技术的风力能源变换系统的组成、逆变器的PWM控制方法以及能量最大化的控制策略.以电力电子变流技术为基础的能源变换系统具有风能利用效率高,动态响应快等特点.     

基于Simulink的柴油引燃式天然气发动机控制模型开发

为了提高柴油引燃式天然气发动机在中小负荷的热效率,采用具备电子节气门的电子控制系统,利用Simulink软件开发了针对该系统的具有电子节气门控制功能的发动机控制模型,通过自动代码生成工具生成嵌入式代码,并下载至发动机控制器进行试验。试验结果表明,该节气门控制算法具有较好的控制效果,发动机控制算法能够有效控制发动机中小负荷的混合气空燃比,明显提高热效率。     

参数横摇薄弱性衡准研究

鉴于国际海事组织（IMO）第二代完整稳性衡准工作组正在制定参数横摇薄弱性衡准。文章首先编制了参数横摇第一层和第二层薄弱性衡准的计算程序,其中采用解析稳态解法求解横摇响应,并给出了衡准中关键参数即波浪中稳性高变化的计算方法;其次以国际标模 C11集装箱为例详细分析了参数横摇衡准的计算过程,同时分析了横摇阻尼对计算结果的影响;最后通过与试验结果的比较,验证了衡准方法的一致性及程序的可靠性。     

铁路列流图自动生成算法

针对铁路列流图目前由手工绘制存在的缺陷,研究铁路列流图自动生成算法。根据图论理论,从列流图中的列流路径由车流组织确定而无需考虑路径长度的特点出发,借鉴最短径路算法,提出站点连通路径标号算法,用来求出起点至终点经历的站点集合。采用点集合及边集合自动生成算法,自动生成路网内的车站、衔接方向、道岔及铁路线。分析不同情形下径点偏移的横纵坐标关系,按列流线等间距绘制的要求提出列流线自动生成算法。依据自动生成算法开发列流图编制软件,运用该软件自动生成具有65条列流线的某路网列流图,证明列流图自动生成算法能够很好地提高设计效率和质量,同时有助于实现列流图的规范化。     

发展可再生能源及变流技术的一些问题

对国内外当前可再生能源发展的背景,特别对2005年11在北京召开的第二届国际可再生能源大会的主要精神,国内外可再生能源利用的发展概况和我国在发展可再生能源方面的政策和举措进行了简要的概述.对风能发电、太阳能发电、生物能及燃料电池发电与大功率变流技术发展的关系进行了讨论.     

论建设新一代的免维修给水排水设备

根据铁路给水排水行业快速发展和技术装备迅速实现现代化的要求 ,揭示了新一代免维修设备的内涵 ,明确了免维修设备的标志 ,阐明了建设免维修给水排水管道的技术和管理要求 ,同时提出了免维修设备的管理意见     

Can induced traffic be measured by surveys?

This paper addresses the feasibility of measuring induced traffic by means of appropriately designed surveys. The problems which confront any attempt to measure induced traffic are described and discussed. They include: inherent variability of traffic data, difficulty in establishing what would have happened in the absence of the scheme, uncertainties in the attribution of cause and difficulty in determining the most appropriate time to conduct surveys. Some of these problems have no solution while others can be reduced with an appropriate programme of surveys and control studies. Calculations are made of the sample sizes required to achieve various levels of target accuracy. It is concluded that, given an appropriate programme of traffic counts including control studies and extensive screenlines, it should be possible at relatively modest cost and with reasonable precision, to measure the increases in traffic associated with a scheme and to identify how much of that increase is due to rerouteing. Any further disaggregation of this extra traffic into that which is due to change of mode, change of destination and increased frequency, is much more problematic. The basic traffic counts would need to be supplemented by a programme of public transport surveys, registration plate marking and/or roadside interviews, which would add very considerably to the cost of the exercise. However, even with considerable expenditure, adequate precision may be difficult to achieve and attribution of cause impossible to make.     

An activity-episode generation model that captures interactions between household heads: development and empirical analysis

In this paper, we develop an approach for modeling the daily number of non-work, out-of-home activity episodes for household heads that incorporates in its framework both interactions between such members and activity setting (i.e. independent and joint activities). Trivariate ordered probit models are estimated for the heads of three household types – couple, non-worker; couple, one-worker; and couple, two-worker households – using data from a trip diary survey that was conducted in the Greater Toronto Area (GTA) during 1987. Significant interactions between household heads are found. Moreover, the nature of these interactions is shown to vary by household type implying that decision-making structures and, more generally, household dynamics also vary by household type. In terms of predictive ability, the models incorporating interactions are found to predict more accurately than models excluding interactions. The empirical findings emphasize the importance of incorporating interactions between household members in activity-based forecasting models.     

沥青路面温差发电系统设计分析与试验研究

针对沥青路面集热研究现状,设计了一种利用导热铝片取代水流管网作为载热体的沥青路面温差发电系统,通过构建沥青路面集热数学模型、导热铝片传热数学模型和半导体温差发电数学模型等动态仿真模型,对系统进行理论分析和试验研究,结果表明采用导热铝片作为载热体可以增强沥青混凝土内的热量转移,从而降低路面的温度梯度,减少路面的热应力,同时温差发电模块可将路面热量转化为电能输出,作为城市市政工程用电的补充.