ATM技术特性及应用

ATM是一项全新的技术,近年来得到了迅速的发展。介绍了ATM的技术原理和接八方式,并在此基础上开发新的应用．使得城市公共ATM宽带网朝着具有极大信息变换及传输能力并能包容各种业务的全业务网络的方向发展,并结合实例描述了某市ATM网络的建设和发展状况。     

H2控制方法中加权函数对海洋平台振动控制效果的影响分析

采用具有鲁棒性能的H2控制方法对海洋平台的过度振动进行控制,给出与控制效果相关的加权函数W1和与控制力相关的加权函数W2的表达形式,以一典型平台为例,重点分析加权函数中各参数对振动控制效果及所需控制力的影响趋势,并对加权函数中的各参数进行敏感性分析。     

政策法规变化对公路煤炭运输行业的影响研究

随着排放法规升级、“公转铁”等政策的实施,促使公路煤炭运营模式进入深度调整期,收益模式由原来的粗放型逐步向集约型转化,文章通过对典型公路煤炭运输模式进行市场调研,并用TCO全生命周期运营成本分析法对影响公路煤炭运输运营成本的相关因素进行分析得出:1)公路煤炭运输在法规的影响下运营成本升高、用户收益空间变窄;2)公路煤炭运输行业开始寻求运营成本更低的集约化运输模式,以实现降本增效。     

温度对油气管道的CO2腐蚀速率的影响研究

为了研究温度对油气管道CO2腐蚀速率的影响,采用A3钢挂片全浸泡实验方法,在不同温度和含饱和CO2的油田模拟水中进行腐蚀试验,并与不合CO2的油田模拟水溶液中的全浸泡腐蚀试验结果进行比较,从而得出温度对油气管道腐蚀速率的影响.     

Large eddy simulations for quasi-2D turbulence in shallow flows: A comparison between different subgrid scale models

In this study, the performance of the horizontal large eddy simulation module, developed at the University of Leuven (HLES-KULeuven module) is assessed. A comparison between different subgrid scale models has been carried out. The study is concerned with the non-rotating and unstratified flows. The results of the simulation for an oscillatory backward facing (BFS) flow are presented in case of an expanding flume based on a one-length scale approach and a two-length scale approach. Three subgrid scale (SGS) models have been tested: Smagorinsky SGS model (Smagorinsky, J., (1963). General circulation experiments with the primitive equations, I. the basic experiments. Monthly Weather Review, 91(3), 99–164), Uittenbogaard SGS model (Uittenbogaard, R.E., and van Vossen, B., (2004). Subgrid-scale model for quasi-2D turbulence in shallow water. Shallow Flows. Jirka and Uijttewaal (Eds.), Taylor & Francis Group, London, ISBN 90 5809 700 5) and a proposed two-length scale approach. The first two models are considered to be a one-length scale models. A simulation without a subgrid scale model for the horizontal mixing has also been conducted. In all simulations, a quadratic friction model parameterizes the dissipation produced by the 3D-subdepth scale turbulence. The two-length scale concept uses a newly mixing length formulation for the quasi-2D turbulence and doesn't depend on the filter width in contrast to the one-length scale approach, in which the mixing length is function of the filter width. The outputs of the HLES-KULeuven module have been compared with the experimental data taken from Stelling, G.S., and Wang, L.X., (1984). Experiments and computations on separating flow in an expanding flume. Dept. Civil Engineering, Delft University of Technology, Report 2–84.). The two-length scale approach has been validated with experimental data from SERC Flood Channel Facility at HR Wallingford. In general, there is a qualitative agreement with the experimental data. It has also been found that the two-length scale approach produces more elongated and less isotropic vortex than the one-length scale models.     

二维凹槽内加机翼减阻效果的数值分析

对平板、二维凹槽和二维凹槽内加机翼三种模型进行对比分析,数值探讨二维凹槽内加机翼的减阻效果。数值摸拟采用商业软件fluent,结果表明在二维凹槽内加入机翼后的阻力比平板的阻力有14．8％的减阻效果。     

沥青混合料细观结构离散元分析

为了在细观层次上分析沥青混合料的力学特性,本文用多边形单元模拟粗集料,球形单元粘结在一起模拟沥青玛蹄脂,在细观尺度上建立比较直观、清晰的离散元数值模型,采用3种接触模型描述沥青混合料内部的相互作用,并进行单轴压缩虚拟试验,分析沥青混合料的变形与应力情况。论文对虚拟试验结果进行分析,得出一些重要结论,并对本文的后继研究提出有意义的建议。     

In及In-Sn电极电还原CO2的研究

CO2电还原技术在降低"温室效应"、缓解能源危机及消除密闭环境的CO2等方面都有很重要的意义.本文利用电沉积的方法制备了用于电还原CO2的In及In-Sn电极,在三电极测试体系及电解槽中,对所制备的电极进行活性及稳定性测试.在常温常压和2 000 A·m-2的电流密度下,所制备的In和In-Sn电极(43 cm2)电还原CO2,生成HCOOH的速率分别达到0.585 L·h-2,0.922 L·h-2.在40 h的电解测试中,两者皆具有较好的稳定性.In-Sn较In具有更高的CO2电还原活性,是一类更具应用前景的电极.     

自由能最小化方法处理化学激光器燃烧产物组份的探讨

简单阐述了最小自由能法的原理,行迭代求解,用Fortran语言编写计算程序,烧室中不同配比下的燃烧温度和平衡组份,在数学上采用了线形化迭代方法,对线形方程组进并利用此方法计算了NF3-H2体系的化学激光器燃为进行这方面的实验提供了参考。     

TiO2光催化剂的改性研究

本文综述了离子掺杂、贵金属沉积以及与半导体复合等方法来改善TiO2可见光光催化活性的研究进展,简要分析不同方法对其光催化性能的影响,并展望了TiO2光催化剂今后的研究方向。