检索结果-南通市图书馆

Large eddy simulation of flow in a street canyon with tree planting under various atmospheric instability conditions

引用

Science China(Technological Sciences) 2010年第7期53卷 1928-1937页

作者： GU ZhaoLin1, ZHANG YunWei2 & LEI KangBin3.1 school of human settlements and {3. engineering, xi’an jiaotong university, xi’an 710049, China 1 school of Energy and Power engineering, xi’an jiaotong university, xi’an 710049, China 3.RIKEN Institute, Wako, Saitama, 3.1-0198, Japan 1. school of human settlements and {3. engineering Xi’an Jiaotong University Xi’an 710049 China2. School of Energy and Power Engineering Xi’an Jiaotong University Xi’an 710049 China3. RIKEN Institute Wako Saitama 351-0198 Japan

In this work, a large eddy simulation (LES) model, which includes momentum and heat source (or sink) inside the tree planting layer, is proposed for the simulation of flow in a street canyon with tree planting. Vegetation canopy layer simulation shows that this model can be used to simulate the velocity distribution and temperature variation inside the canopy layer. Effects of atmospheric instability on flow and pollutant distribution in a street canyon with tree planting of an aspect ratio of 0.5 are studied. Results show that compared with the canyon with no tree planting (or the exposed street canyon), the canyon with tree planting shows a reduced wind circulation and pollutant exchange rate (PER) at the top layer of the street canyon, which induces the increase in the pollutant concentrations near road surface, leeward wall and windward wall. When street canyon atmosphere is under a strongly unstable condition, wind velocity decreases while pollutant concentration is increased in the areas near the street canyon top, road surface, leeward and windward walls, compared with the wind velocity in the street canyon with the neutral stratification. When street canyon atmosphere is under a weakly unstable condition, wind velocity weakens near the street canyon top and windward wall, but strengthens near the road surface and leeward wall, and pollutant concentration is decreased near the leeward and windward walls and is increased between the two rows of trees. When the street canyon atmosphere is under an unstable condition, PER is lower than that under the neutral stratification.

关键词： street canyon flow tree planting atmospheric instability large eddy simulation pollutant concentration distribution

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Nitrogen isotopic composition of plant-soil in the Loess Plateau and its responding to environmental change

引用

Chinese Science Bulletin 2009年第2期54卷 272-279页

作者： LIU WeiGuo1,2 & WANG Zheng1,3.1 State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, xi’an 710075, China 2.xi’an jiaotong university, school of human settlement and civil engineering,{3., China 3.Graduate {3. of Chinese Academy of Sciences, Beijing 100049, China Chinese Acad Sci Inst Earth Environm State Key Lab Loess and Quaternary Geol Xian 710075 Peoples R China.

The nitrogen isotope of soil is of emerging significance as an indicator of climatic change and biogeochemical cycle of nitrogen in nature systems. In this paper, the nitrogen content and isotopic composition of modern ecosystems from arid and semiarid Loess Plateau in northwestern China, including plant roots and surface soil, were determined to investigate trends in δ15N variation of plant roots and soil along a precipitation and temperature gradient in northwestern China under the East Asian Monsoon climate condition. The δ15N values of surface soil from the study area vary from ?1.2‰ to 5.8‰, but from -5.1‰ to 1.9‰ in the plant roots. Our results indicate that (1) although the isotopic compositions of both plant roots and surface soil change with a similar trend along the climate gradient, the apparent nitrogen difference between plant roots and soil existed, with -δ15N values ranging from 0.3. to 7.2‰ with average of 4.1‰; and (2) mean annual precipitation (MAP) is the dominant factor for isotopic composition of plant-soil nitrogen in the Loess Plateau, and the δ15N values are less correlated with MAT; we suggest that nitrogen isotopic composition of soil is a potential tracer for environmental changes.

关键词：氮同位素物理性质化学性质环境论

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Experimental Investigation on Local Air Age and Air Distribution of Stratum Ventilation

引用

湖南大学学报（自然科学版） 2009年第S1期36卷 35-39页

作者： WANG Feng-hao,LI Yuan-bin,LIU xiao-dong,WANG xin-ke(school of {3. settlements and {3. engineering,xi’an jiaotong university,xi’an,Shaanxi 710049,China) school of human settlements and {3. engineering Xi'an Jiaotong University Xi'an 710049 China

Because of the multiple problems on high energy consumption and unbalanced thermal comfort caused by the traditional ventilation system,a new concept of ventilation-stratum ventilation has been proposed,which sends the fresh air to the breathing zone *** this paper,the local air distributions of the displacement ventilation and the stratum ventilation in a model office were *** air ages in the breathing zone for the displacement ventilation and stratum ventilation were compared with the tracer gas concentration decay *** decay curves of tracer gas concentration for these two ventilation systems in the breathing zone were obtained,and the air ages were *** experimental results show that the stratum ventilation system can offer lower air age for four mechanically ventilated cases in the breathing zone,and it can also provide better thermal comfort,which renews the air of breathing zone more quickly and reduces the energy consumption in some *** experimental investigation provides a theoretical basis for the application of stratum ventilation system.

关键词： ventilation air quality air age distribution

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A method for support stiffness failure identification in a steel spring floating slab track of urban railway: a case study in China

引用

Journal of Zhejiang university-Science A(Applied Physics & engineering) 2024年第3期25卷 206-222页

作者： Junyuan ZHENG Caiyou ZHAO Duojia SHI Ping WANG Jian WANG Bolong JIANG xi SHENG Key Laboratoryof High-speed Railway engineering Ministry of EducationSouthwest Jiaotong UniversityChengdu 60031China school of civil engineering Southwest Jiaotong UniversityChengdu 610031China 01 DYNA(Qingdao)Test&Data Co. Ltd.Qingdao 266000China Rail Transit Digital Construction and Measurement Technology National engineering Research Center China Railway Design CorporationTianjin300308China Institute of Urban Smart Transportation&Safety Maintenance Shenzhen UniversityShenzhen 518060China

The extensive use of steel spring floating slab tracks has effectively addressed the challenge of alleviating the environmental vibrations induced by urban rail transit ***,under the combined action of train dynamic loads and complex environmental factors,problems,such as the fracture of steel spring vibration isolators and suspension vibrations induced by the uneven settlement of the base,often *** failure of isolator support stiffness is often hidden in its early stages and is challenging to identify by conventional detection *** the same time,it will aggravate the wheel-rail interaction,accelerate the deterioration of track structure,and even affect the driving *** study first establishes a detailed coupled train-floating slab track-foundation analytical *** the influence of the vibration isolator support stiffness failure on the dynamic indices of the floating slab track system response is analyzed.A set of defect identification methods that can detect the number of failed steel springs,severity of damage,and their location is ***,an intelligent monitoring system for support stiffness of floating slab track is built by combining the density-based spatial clustering of applications with noise algorithm and statistical data analysis and is applied to a rail line in southern *** a three-year monitoring campaign,a suspension failure and a fracture of a steel spring were each successfully detected and detailed failure information was *** investigation results were consistent with the damage identification *** repair,the track structure dynamic response returned to the average pre-damage level and further deterioration had been *** proposed damage identification methods and monitoring system provide an approach for intelligent identification of track structure support stiffness failures.

关键词： Floating slab track Support stiffness Detailed analytical model Failure identification Monitoring system

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in numerical methods for the solution of population balance equations for disperse phase systems

引用

Science China Chemistry 2009年第8期52卷 1063-1079页

作者： SU JunWei1,GU ZhaoLin2,3.& XU X.Yun41 Department of Mechanical engineering and Automation,school of Mechanical engineering,{3.’an {3. university,{3.’an 710049,China 2 Key Laboratory of Mechanics on Disaster and Environment in Western China,Ministry of Education,Lanzhou 73.000,China 3.Department of Environmental Science and Technology,school of human settlements and civil engineering,{3.’an {3. university,{3.’an 710049,China 4 Department of Chemical engineering,Imperial College London,London SW7 2AZ,UK 1. Department of Mechanical engineering and Automation School of Mechanical Engineering Xi’an Jiaotong University Xi’an 710049 China 2. Key Laboratory of Mechanics on Disaster and Environment in Western China Ministry of Education Lanzhou 730000 China 3. Department of Environmental Science and Technology School of Human Settlements and Civil Engineering Xi’an Jiaotong University Xi’an 710049 China 4. Department of Chemical engineering Imperial College London London SW7 2AZ UK

Accurate prediction of the evolution of particle size distribution is critical to determining the dynamic flow structure of a disperse phase system.A population balance equation(PBE),a non-linear hyperbolic equation of the number density function,is usually employed to describe the micro-behavior(aggregation,breakage,growth,etc.) of a disperse phase and its effect on particle size *** solution is the only choice in most *** this paper,three different numerical methods(direct discretization methods,Monte Carlo methods,and moment methods) for the solution of a PBE are evaluated with regard to their ease of implementation,computational load and numerical *** attention is paid to the relatively new and superior moment methods including quadrature method of moments(QMOM),direct quadrature method of moments(DQMOM),modified quadrature method of moments(M-QMOM),adaptive direct quadrature method of moments(ADQMOM),fixed pivot quadrature method of moments(FPQMOM),moving particle ensemble method(MPEM) and local fixed pivot quadrature method of moments(LFPQMOM).The prospects of these methods are discussed in the final section,based on their individual merits and current state of development of the field.

关键词： population balance equation direct discretization method Monte Carlo method moment methods disperse phase system

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The application of geographic information technology to coastal geomorphology

引用

Acta Oceanologica Sinica 2009年第5期28卷 49-57页

作者： GUO Wei LI Shuheng ZHU Dakui school of human settlements and {3. engineering Xi＇an Jiaotong University Xi＇an 710049 China Department of Computer Sciences Xi＇an Jiaotong University Xi＇an 710049 China Department of Urban and Resources Sciences Northwest University Xi＇an 710032 China Faculty of Environmental Sciences University of Waterloo Waterloo N2L3G1 Canada Key Laboratory of Coast ＆ Island Development of Ministry of Education Nanjing University Nanjing 210093 China

With the development of modern oceanic observation technologies, coastal survey data have been experiencing a substantial growth. The integration management of the data from different disciplines, different sources and different formats has become a major research field in coastal geomorphology by using Geographic Information System （GIS）. This paper puts forward a new methodology framework of GIS techniques in coastal ocean geomorphology, including data acquisition, process, analysis, and representation. It focuses on some major GIS techniques to study the land-ocean interaction mechanism, such as spatial analysis, submarine topography model and three-dimension （3.） visualization, and apply its result to coastal urban planning, harbor site selection and geomorphology environment about coral reef and islands on the continental shelf. The case studies cover the whole coastal ocean to serve the social community, economical development and diplomatic rights for decision-making all round in the coastal zone. The research shows clearly that the application of coastal multi-source geospatial platform has changed the traditional coastal geomorphology science dramatically from its research scope, fields and methods, however, as made clear in this paper, extracting accurate information from remote sensing data and GIS databases for coastal geomorphological applications is a nontrivial challenge that requires the combined knowledge and skills of information scientists and geomorphologists.

关键词： coastal geomorphology geographic information system (GIS) spatial analysis threedimensional visualization

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

RESEARCH ON THE BEST SLOPE GRADIENT OF SLOPE SOLAR INDUCED CONVECTIVE FLOWS POWER GENERATION SYSTEM

RESEARCH ON THE BEST SLOPE GRADIENT OF SLOPE SOLAR INDUCED C...

引用

2007世界太阳能大会：太阳能与人类居住

作者： Wei Jing Wang Fenghao school of human settlements and {3. xi’an jiaotong university xi ’an 710049 China Zhao Liang State Key Laboratory of Multiphase Flow in Power engineering xi’an jiaotong university xi ’an 710049 China

＜正＞Based On the monthly average solar radiation data from 1991 to 2000 year of China and the theory of the solar induced convective flows power generation,the feasibility of building slope solar induced convective flows power generation in west areas of China was analyzed and the gradient’s inflection on system power and efficiency was studied in this paper.A MATLAB code was compiled in this paper to get the best gradient of different *** the slope system was compared with horizontal system in performance under the same *** results show that the best gradient of the solar induced convective flows power generation is similar to the latitude;the slope collector can serve as a part of the chimney.

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

清代官办书院的城市社会学功能研究

引用

人类文化遗产保护 2015年第1期7卷 67-71页

作者：周晶李天西安交通大学人居环境与建筑工程学院

清代官办书院是中国古代教育体系的重要组成部分,也是近代中国高等教育发展的基础与平台。清代官办书院多建于当时州府一级城市,除了承担官学的基本职能之外,还具有某些城市社会学功能,这些功能对其城市文化风格的形成起到了非常重要的... 详细信息

清代官办书院是中国古代教育体系的重要组成部分,也是近代中国高等教育发展的基础与平台。清代官办书院多建于当时州府一级城市,除了承担官学的基本职能之外,还具有某些城市社会学功能,这些功能对其城市文化风格的形成起到了非常重要的作用。本文试图通过对清代城市中的官办书院从书院等级、选址、建筑格局、发展流变等方面的研究,说明中国古代官办书院对城市文化风格的形成与城市发展有很大贡献。

关键词：清代官办书院城市社会学功能

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

天津法租界市政建设管理机制研究(1900-1943.

引用

人类文化遗产保护 2015年第1期7卷 75-80页

作者：李天周晶西安交通大学人居环境与建筑工程学院

1900年天津法租界扩张之后,法租界设立公共工程委员会,系统管理市政建设。公共工程委员会负责法租界内道路、卫生设施、公共建筑等市政工程的规划、招标与管理,并设置顾问工程师对市政工程进行监督。通过合理的行政机构与严格的法规,天... 详细信息

1900年天津法租界扩张之后,法租界设立公共工程委员会,系统管理市政建设。公共工程委员会负责法租界内道路、卫生设施、公共建筑等市政工程的规划、招标与管理,并设置顾问工程师对市政工程进行监督。通过合理的行政机构与严格的法规,天津法租界完善了城市设施与城市管理,呈现出现代化的城市面貌。

关键词：天津法租界市政建设管理机制

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The Comparison of Environmental Time Series Statistical Prediction Methods

The Comparison of Environmental Time Series Statistical Pred...

引用

2012 Asia Pacific Conference on Environmental Science and Technology(APEST 2012)

作者： Jing Zhang1 a Hongqiang Jiang1 b Zhijing Chen2 c Xuxiang Li2 d and Yaling Lu1 e 1 Key Laboratory of Environmental Planning and Policy Simulation Chinese Academy for Environmental Planning Beijing 100012 China 2 Department of Environmental Science and Technology school of human {3. and {3. engineering xi’an jiaotong university xi’an 710049 China

Four approaches of time-series analysis,neural network,wavelet analysis,nonparametric regression were briefly outlined in the beginning of this *** daily average concentrations of SO2,NO2 and PM10 in xi’an during September 27,2006 to May 3.2008 were analyzed using different methods,e.g.,time-series analysis,BP neural network,RBF neural network,de-noising BP neural network,de-noising RBF neural network,and nonparametric regression,and the concentrations of SO2 in xi’an from April 4,2008 to May 3.2008 were *** forecasting results were compared and discussed in order to evaluate the effects of different *** results show that all the methods mentioned can be used in time series analysis of air pollutants and the de-noising BP neural network is more scientific.

关键词： Time Series Analysis Artificial Neural Networks Wavelet Analysis Nonparametric Regression forecast data analysis.

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：