用准定常升力线理论预报螺旋桨在非均匀流场中的性能

本文应用准定常升力线理论预报船用螺旋桨的性能,建立了适合中型计算机的程序。通过四个桨模的敞水试验和性能计算结果比较表明,对于计算螺旋桨的推力与转矩系数,只要应用升力线理论加上简单的粘性经验修正及升力面影响修正,不必作边界层计算即可得到比较满意的结果。伴流场中单个叶片推力与转矩脉动计算表明,用升力线作计算时,伴流产生的水流弯曲对推力、转矩脉动有较明显的影响,对推力偏心度则影响不大,计算所得的推力、转矩脉动可供计算主机扭振及轴系振动的外力作参考。     

Assessment of policies and detection of unintended effects: Guiding principles for the consideration of methods and tools in policy-packaging

Single policies or entire policy packages are often assessed using different methods aiming at a quantification of effects as well as the detection of undesired outcomes. The knowledge of potential impacts is essential to take informed policy actions. Hence, there is a constant need for efficient assessment approaches to support policy decision-making. A broad range of such assessment methods is used in policymaking. Some of them are using quantitative data; others are characterized by qualitative information, observations or opinions. Practical experiences with transport policy prove that these methods all have their pros and cons, but none of them are able to detect the full range of effects. This leads to important questions this article deals with, such as what are the strengths and limitations of the different tools and methods for assessing impacts, and how should different approaches be integrated into the policymaking processes?We analyze the ability of assessment methods to detect different kinds of intended and unintended effects, and introduce the concepts of structurally open (mainly qualitative) and structurally closed (mainly quantitative) methods. It is argued that these concepts support making the pros and cons of the tools and methods more explicit and, thus, allow integrating the different tools and methods into the process of policy packaging. Based on a policy package example, we provide practical recommendations on how to integrate different assessment methods adequately and show that both quantitative and qualitative tools should be used in different phases of the process. The main recommendation is to alternate the application of assessment methods with structurally open methods used in the beginning and the end of the policymaking process and applying structurally closed methods in between.     

The underground economy: Tracking the higher-order economic impacts of the São Paulo Subway System

Over one million workers commute daily to São Paulo City center, using different modes of transportation. The São Paulo subway network reaches 74.2 km of length and is involved in around 20% of the commuting trips by public transportation, enhancing mobility and productivity of workers. This paper uses an integrated framework to assess the higher-order economic impacts of the existing underground metro infrastructure. We consider links between mobility, accessibility and labor productivity in the context of a detailed metropolitan system embedded in the national economy. Simulation results from a spatial computable general equilibrium model integrated to a transportation model suggest positive economic impacts that go beyond the city limits. While 32% of the impacts accrue to the city of São Paulo, the remaining 68% benefit other municipalities in the metropolitan area (11%), in the State of São Paulo (12.0%) and in the rest of the country (45%).     

The Gothenburg congestion charge. Effects,design and politics

This paper summarizes the traffic effects of the Gothenburg congestion charges introduced in 2013. The system is similar to the system introduced in Stockholm in 2006; both are designed as time-of-day dependent cordon pricing systems. We find that many effects and adaptation strategies are similar to those found in Stockholm, indicating a high transferability between smaller and larger cities with substantial differences in public transport use. However, there are also important differences regarding some of the effects, the accuracy of the model forecasts and public support arising from different topologies, public transport use, congestion levels and main objectives communicated to the public. Finally, the Gothenburg case suggests that whether congestion charges are introduced or not depends on the support among the political parties, and that this is determined primarily by the prevailing institutional setting and power over revenues, and to a lower extent by the public support, and benefits from congestion reduction.     

移就的修辞方式修辞效果及翻译方法

移就是在特殊语言环境中改变词语搭配关系的一种临时迁就,是词语搭配的创造性运用。其常用的修辞方式分为移人于物、移物于人、移物于物三种。其修辞效果是能传达丰富的情感,产生出无穷的艺术张力。移就修辞格的翻译可采用直译法、位置还原法、状语化法和分译法等。     

一种新型抑尘剂对道路扬尘的抑制特性

以泰州大桥项目施工现场便道路面扬尘为研究对象,对东南大学市政工程系研制的新型道路扬尘抑制剂与纯水进行抑尘对比试验研究,重点分析了抑尘剂和纯水的渗透效果,蒸发量与时间的变化关系及抗风与抗雨淋性能.结果表明抑尘剂的渗透速率优于纯水,但二者的渗透变化规律相似,分别在800s与200s内渗透速率最大,随后二者渗透速率趋于平缓....     

多振型效应对铁路高柔桥墩弹塑性地震响应的影响

对FEMA356和ATC-40中考虑多自度效应的非线性静力分析法进行改进。并在FEMA440考虑土-结构相互作用能力谱法基础上,以我国西南某铁路特大桥桥墩为研究对象,选取与我国《铁路工程抗震规范》Ⅱ类场地相符合的80条强震记录,利用FEMA440性能点轨迹法求解高柔桥墩结构延性及性能点;并与80条强震记录非线性时程分析计算结果平均值进行比较。验证本文改进的非线性静力分析法反映高柔桥墩多自度效应的合理性,及考虑土-结构相互作用能力谱法在铁路桥梁工程中应用的可行性。     

本科医学生的心理卫生调查研究

本文以西安医科大学219名本科二年级学生为对象,采用心身健康状况(CMI)、人格(EPQ)、气质、情绪状态(SAS、SDS)等五个量表,进行了心理卫生调查研究。发现医学生中处于焦虑抑郁情绪状态的百分数较高,分别为44.29%、21.00%,有51.14%的人情绪不稳定,10.50%的人有“神经症倾向”,以艾森克人格问卷分析中正常人的均值作常模,与其进行比较,内外向E的均值、神经项N的均值均增高。再与北京医科大学研究生的调查结果进行比较,医学生在焦虑、抑郁、情绪不稳定方面,都明显高于医学研究生。本文还就医学生产生焦虑、抑郁、情绪不稳定的原因进行了分析。     

关于足球比赛中运动员心理状态的探讨

足球比赛情况错综复杂、变化莫测,强与弱是相对的.在一定的条件下,优势与劣势可以相互转化.因此,教练员在注意加强运动员技术、战术和身体素质训练的同时,还要注意加强运动员良好心理素质的训练与培养.     

生态责任约束下港口与其物流系统的联动效应

港口在为社会经济发展提供保障的同时,应在生态责任的约束下打造与其物流系统间的联动效应,并考虑港口自身的发展模式。文中构建了港口及其生态物流系统的理论框架,基于与一般绿色物流的不同,分析了港口与物流系统中其他节点企业及与最终客户之间如何实现联动。针对生态责任约束下港口自身的发展给出了相关对策及建议,认为应加强生态型中转设施、临港生态工业园区等建设工作。对构建以港口为中心的生态物流系统具有一定意义。