论乾嘉汉学繁荣的原因

清代乾隆、嘉庆两朝,考据学全盛,形成了乾嘉学派.乾嘉学派的出现及乾嘉汉学的繁荣,一方面受政治、社会、文化等外缘因素的影响,另一方面是学术自身发展的必然趋势.这两方面相互作用的合力促成了乾嘉汉学的兴盛.     

Grid convergence study in the resistance calculation of a trimaran

As a new type of hull form, trimaran has remarkable excellent performances and has drawn more and more attention. When the viscous CFD technology now available is applied to the research of resistance performance of trimaran, the spatial discretization would usually result in the grid error and uncertainty, and thus the considerable discrepancy between the numerical results and the experimental data. In order to ascertain how much the grid would affect the calculation, the grid convergence should be studied. A mathematical trimaran was chosen as an example, with the commercial code CFX for the simulation, VOF for surface treatment, and the grid study was carried out based on two different turbulence models. It was concluded that carrying out grid study is helpful in estimating the grid error and uncertainty, and indicating the direction of improving the credibility of the numerical calculation, and, in addition to grid errors and uncertainties, the turbulence modeling errors and uncertainties contribute to the simulation errors.     

黄韩候铁路二线复杂条件下路基支挡方案比选及设计

以黄韩候铁路二线一处复杂条件下的路基工程为例，在收集翔实可靠资料的基础上,通过各种控制因素的分析研究，开展多种支挡方案比选，提出各种控制因素的具体对策，既考虑了整体支挡方案的合理性，又充分重视各个控制点工程措施的针对性、有效性和可实施性，顺利地解决了复杂条件下路基工程难题。     

The GRAAL of carpooling: GReen And sociAL optimization from crowd-sourced data

Carpooling, i.e. the sharing of vehicles to reach common destinations, is often performed to reduce costs and pollution. Recent work on carpooling takes into account, besides mobility matches, also social aspects and, more generally, non-monetary incentives. In line with this, we present GRAAL, a data-driven methodology for GReen And sociAL carpooling. GRAAL optimizes a carpooling system not only by minimizing the number of cars needed at the city level, but also by maximizing the enjoyability of people sharing a trip. We introduce a measure of enjoyability based on people’s interests, social links, and tendency to connect to people with similar or dissimilar interests. GRAAL computes the enjoyability within a set of users from crowd-sourced data, and then uses it on real world datasets to optimize a weighted linear combination of number of cars and enjoyability. To tune this weight, and to investigate the users’ interest on the social aspects of carpooling, we conducted an online survey on potential carpooling users. We present the results of applying GRAAL on real world crowd-sourced data from the cities of Rome and San Francisco. Computational results are presented from both the city and the user perspective. Using the crowd-sourced weight, GRAAL is able to significantly reduce the number of cars needed, while keeping a high level of enjoyability on the tested data-set. From the user perspective, we show how the entire per-car distribution of enjoyability is increased with respect to the baselines.     

消减波浪荷载的桥梁沉箱基础外形设计研究

基于波浪场中动水压强的空间分布特征,提出了消减跨海桥梁沉箱基础波浪荷载的方法:一是优化基础横截面外形,调节基础横截面外轮廓不同位置波浪压力的相位差,减小基础所受到波浪力和力矩;二是优化基础竖截面外形,减小水面附近波浪能量集中区域的截面尺寸,增大靠近海床面区域的截面尺寸,将基础下部的迎浪面设置为外伸斜面,利用斜面上波浪压力竖向分力产生的力矩抵消部分水平分力产生的力矩,从而消减桥梁基础上的总波浪力矩。对于大尺度矩形和圆端矩形截面的桥梁深水沉箱基础,基于势流绕射理论和边界积分方法进行分析,结果表明,相比于矩形截面,采用圆端矩形截面可有效减小基础的波浪力和力矩;相比于上下等截面的基础,采用下部迎浪面设置外伸斜面的基础可以大幅减小基础的波浪力矩。研究成果可为跨海桥梁深水基础设计提供参考。     

岩石各向异性的单轴压缩试验研究

岩体具有不同程度的各向异性。对现场取样的各向异性岩石进行了单轴压缩试验,确定了描述岩石横观各向同性特征的5个弹性常数以及各向异性岩石的强度指标,并分析了各参数的变化规律。研究结果可为各向异性岩体工程计算和分析提供参考依据。     

红砂岩崩解特性及其路堤填筑技术研究

结合某高速公路大型模拟试验路堤及实体工程试验路段试验研究,从研究红砂岩的化学成分与结构特征入手,深入探讨了红砂岩崩解试验方法及其崩解机理与特性,从而提出了红砂岩的有效工程分类方法,并在此基础上,深入研究了红砂岩作为路用材料的路堤填筑技术,进而确定出红砂岩路基填筑的合理施工工艺,并提出了相应合理的路基填筑质量控制标准及其检测方法,为红砂岩地区高速公路路堤填筑提供了可靠的技术保证。     

三水源新安江与相应涨差耦合模型的研究及应用

本文从河道非恒定流St．Venant方程组出发，应用水文预报中洪水时段涨差的基本概念，建立了河道洪水预报的相应涨差模型，与区间洪水预报的三水源新安江模型相耦合，建立了三水源新安江与相应涨差耦合模型。经在资水拓溪～桃江区间洪水预报中应用，效果较好。     

冲击式压路机两个重要参数的探讨研究

通过对冲击式压路机工作时对牵引力的要求及大轴受力状况的分析计算，给出了两个参数的确定思路和依据，具有一定的探讨和参考价值。     

宜昌长江公路大桥竣工文件编制与研究简介

结合宜昌长江公路大桥建设实际，介绍了公路桥梁建设项目竣工文件编制与研究的必要性，编制与研究的技术线路，主要内容及其特点。