有轨电车系统规划设计思考

作为城市轨道交通系统的组成部分,有轨电车系统规划设计的关键在于认清其在轨道交通系统中所处的功能地位和发挥的价值作用。从分析城市轨道交通的发展背景出发,解读有轨电车面临的发展机遇。探讨合理构建有轨电车系统的规划设计思路,以及有轨电车如何适应生态文明和社会文明的发展需要。重点阐述在有轨电车规划设计过程中如何实现与多层级轨道交通系统的协调、与城市空间用地的互动,以及与城市综合交通系统的衔接。     

基于轨迹数据的车辆跟驰行为分析与建模综述

随着轨迹收集技术与数据分析技术的迅速发展,越来越多的车辆行驶轨迹被采集并用于 交通流研究。车辆轨迹数据主要包括车辆运行的位置与时间等信息,利用这些信息可以推算出 车辆的速度、加速度及其与前车之间的空间和时间距离等驾驶行为参量。通过研究轨迹数据可 以揭示车辆自身的运行规律,车辆之间的相互作用规律,道路环境对车辆的作用规律,以及由此 产生的宏观、微观交通流现象,因此,轨迹数据研究受到日益重视。本文简要回顾了与轨迹数据 收集相关的历史,介绍了自然场景下采集的Next Generation SIMulation(NGSIM)数据及实验场景 下采集的车队轨迹数据,并梳理了近几年基于车辆跟驰轨迹的理论研究。首先,分析以交通振 荡、交通回滞为代表的交通流关键实测现象研究工作;整理跟驰行为分析方面的研究成果,包括 不对称跟驰行为、稳定跟驰行为的存在性、跟驰行为的记忆效应、任务难度、随机性、异质性。之 后,介绍基于跟驰行为分析成果而构建的仿真模型。最后,从3个方面评述现有基于轨迹数据的 研究,并提出未来展望：交通流关键实测现象方面,应收集更多不同条件下的数据,并尝试构建更 加普适性的理论或模型解释交通流现象;跟驰行为分析方面,可结合数据挖掘技术或生理、心理 理论,量化驾驶员跟驰特性与生理、心理特征,并将两者结合深入分析跟驰行为的机理;仿真建模 方面,可更多考虑驾驶员生理和心理变量,使模型更具人性化特征,并关注模型的评价方法,注重 模型对实际交通流的解释能力。     

加速中国社会经济发展的非物质化转型已迫在眉睫——三议非物质化是人类社会经济发展的必然趋势

当前我国严峻的生态危机和资源匮乏现状已对全面建设小康社会和实现中华民族的可持续发展构成了巨大威胁。我们必须摒弃发达国家走过并且正在走的以物质消耗和占有为考量标准的社会经济发展模式，并根据我国人口、资源与环境现状尽快实施社会经济发展的非物质化转型，走具有中国特色的全民富裕、全面小康的社会经济发展之路。为此，我们应首先全面提高国民的环境保护综合素质，树立适度消费的新观念；提高国家技术创新能力和自主技术依存度；下决心不惜一切代价从生产、消费源头乃至全过程保护生态环境、治理环境污染和控制资源的消耗，走非物质化的社会经济发展之路，构建资源节约型、环境友好型的和谐社会，为中华民族的可持续发展奠定生态环境和物质资源基础。     

Lengthscales of motions that control air–water gas transfer in grid-stirred turbulence

The relationship between the gas transfer velocity and turbulent lengthscales is investigated experimentally in a grid-stirred turbulent flow. The horizontal velocity field at the water surface is measured using particle image velocimetry (PIV). The gas transfer velocity for oxygen is obtained through reaeration experiments. In addition, the gas transfer process by surface-renewal eddies is visualized using laser-induced fluorescence (LIF) technique, in which carbon dioxide is used as the tracer gas. The definition of the Taylor microscale holds that the root-mean-square (RMS) of the surface divergence is expressed by the square root of the turbulent kinetic energy divided by the Taylor microscale. Experimentally obtained data support this scaling. They show the gas transfer velocity to be proportional to the square root of the RMS of the surface divergence. These experimental results imply that the Taylor microscale is an important parameter for gas transfer velocity at the air–water interface. These relations indicate that a nondimensional gas transfer velocity is proportional to the − 1/4 power of a turbulent-macroscale Reynolds number, which is similar to a small-eddy model, assuming that turbulent eddies with the Kolmogorov scale control the gas transfer process. However, this Reynolds number dependence does not necessarily mean the superiority of turbulent eddies with the Kolmogorov scale in the gas transfer. The LIF visualizations in horizontal and vertical planes close to the air–water interface indicate that the horizontal CO₂-concentration field has a fine spatial pattern, which resembles that of the surface divergence field, and that surface-renewal motions observed in the vertical plane have a larger lengthscale than the Kolmogorov scale. We infer from both PIV and LIF results that the Taylor microscale is an important lengthscale for air–water gas transfer.     

我国交通影响分析技术发展综述

为反映我国交通影响分析（TIA）的技术发展状况和存在的问题，对相关文献进行分析总结，从发展状况、阈值理论、预测模型、交通影响费、制度模式5个方面进行综述。研究显示，我国交通影响分析更重视交通对土地的反作用，实施对象由单体项目向区域化发展，而在交通影响分析调控土地开发强度的能力和为筹集建设资金增开渠道的作用方面尚未得到充分发挥。为了使我国交通影响分析工作更加完善，需要在4个方面进行更深入的研究：区域性交通影响分析理论、适合交通影响分析的分配算法、适合我国的交通影响费制度以及交通影响评价市场的规范化。     

Numerical analysis on free surface waves and stern viscous flow of a ship model

This paper deals with numerical techniques for computing the viscous flow past a ship hull with and without a free surface using a Reynolds-averaged Navier-Stokes solver with global conservation. In the first technique, a coarse grid is used to find an approximate solution to the free surface problem. Interpolation of a fine grid is subsequently carried out, and a more exact solution, particularly in the boundary layer and wake, is obtained. In the second technique, a modified Baldwin-Lomax model is introduced to compute the viscous flow with and without a free surface. These numerical techniques are applied to simulations of the flow around a Series 60 and an SR196C ship model. The results are compared with measurement data, and the usefulness of the numerical techniques is demonstrated.     

掺气分流墩三维流场数值模拟

采用RNGk-ε三维紊流模型和VOF方法,1:1几何建模,对柘林水电站左岸泄洪洞下游掺气分流墩的三维流场进行了数值模拟.在与原型观测试验对比验证的基础上,对该流场的流态、水面、流速分布和压强分布进行了分析.结果表明:流态模拟正确,水面、流速与原型观测结果均能较好吻合;联合作用下的流场,在三维涡体的形成、增强掺气效果和空化空蚀的防止等方面均明显优于无掺气分流墩的流场;三维涡体主要由两股入水主流与池内前部淹没水跃的水体相互摩擦形成;被抛向高空的水翅在下落入水时卷入大量空气,具有较深穿透力,使得波动坎及坎下区域充分掺气,从而破坏空化,防止空蚀.     

社会保险工作在改善劳动关系中的作用

本文梳理了劳动关系的内涵和现阶段我国不和谐劳动关系的表现形式和后果。在此基础上，作者提出社会保险是政府改善不和谐劳动关系的重要举措。     

建筑施工企业年金计划问题研究

本文根据我国政府提出的建立多层次保障体系的要求 ,阐述了企业补充养老保险 ,即“企业年金”在企业发展的作用。合理确定企业年金方案和企业年金的制定和实施办法以及对企业年金的展望。指出了企业年金是社会养老保险三大支柱中极为重要的组成部分 ,它将是很多职工退休后保障晚年生活品质的最主要的收入来源。     

Modelling physical processes of haline stratification in ROFIs with application to the Rhine outflow region

A physical and numerical study is made of the processes governing the stratification and circulation in ROFIs (Regions of Freshwater Influence) where there is an important impact of wind and tides. Observations in the Rhine ROFI showed that the salinity field consists of a mean and a tidally oscillating part. The physical processes are first analysed using the analytical solutions from a one-dimensional two-layer model. A justification is given for the neglection of non-linear advective terms in the equations of momentum and salinity. The dimensionless forms of the solutions can be expressed in terms of a series of dimensionless numbers. It is shown in particular that stratification and cross-shore circulation largely depend on the balance between rotation and turbulent diffusion, which depends in turn on parameters such as the Ekman number, the bottom friction coefficient, the eddy viscosity ratio and the depth of the layer interface. Surface winds either enhance or destroy stratification depending on the wind angle. The response to wind forcing is discussed using classical Ekman theory. To verify the analytical theory numerical tests are performed with a point model including an advanced turbulence closure scheme. Differences arise due to the non-linear interaction between turbulence on the one hand and current shear and stratification on the other hand. It is shown in particular that the amplitude of the tidal forcing and the off-shore horizontal salinity gradient strongly affect the semi-diurnal and semi-monthly variation of stratification. The effect of the wind is found to be in good agreement with the analysis of the two-layer model. Finally, the numerical model is compared with existing observational data in the Rhine ROFI for October 1990.