A MESO-β SCALE SIMULATION OF THE EFFECTS OF BOREAL FOREST ECOSYSTEM ON THE LOWER ATMOSPHERE

Based on the Intensive Field Campaign(IFC-1)data of Boreal Ecosystem-Atmosphere Study(BOREAS).a three-dimensional meso-β scale model is used to simulate the effect of boreal forests onthe lower atmosphere.A fine horizontal resolution of 2 km×2 km is used in order to distinguish thevegetative heterogeneity in the boreal region.A total of 20×25 grid points cover the entire sub-modeling area in BOREAS' South Study Area(SSA).The ecosystem types and their coverage ineach grid square are extracted from the North American Land Cover Characteristics Data Base(NALCCD)generated by the U.S.Geographical Survey(USGS)and the University of Nebraska-Lincoln(UNL).The topography of the study area is taken from the Digital Elevation Map(DEM)of USGS.The model outputs include the components of the energy balance budget within the canopyand at the ground.the turbulence parameters in the atmospheric boundary layer and the wind.temperature and humidity profiles extending up to a height of 1500 m.In addition to the fine timeand spatial step,the unique feature of the present model is the incorporation of both dynamic andbiological effects of the Boreal forest into the model parameterization scheme.The model resultscompare favorably with BOREAS' IFC-1 data in 1994 when the forest was in the luxuriant growingperiod.     

藏北南羌塘盆地毕洛错地区下侏罗统曲色组石膏岩层

对西藏自治区北部南羌塘盆地毕洛错地区下侏罗统曲色组石膏岩层进行了研究。根据岩石地层和生物地层资料,确认毕洛错地区的石膏岩层和油页岩为曲色组的一部分,地质时代为早侏罗世,并确认下侏罗统曲色组在区域上可能是寻找油气、油页岩资源的重要层位之一。     

欧盟RoHS指令与中国的对策

对欧盟RoHS指令的主要内容进行了简述,初步介绍了与RoHS指令相似或者相关的各国的环保指令,讨论了RoHS指令等对我国电子电气行业带来的巨大冲击。简要总结我国电子信息产业部、国家质量监督检验检疫总局、商务部等各管理及技术部门为了应对RoHS指令和提高我国电子电气行业竞争力而作出的相应对策。     

浅议拉萨城市化发展与水文站网调整的关系

城市化是一个国家现代化的必然过程.本文根据近年拉萨市城市化步伐的加快,提出水文站网要适应城市的发展,逐步在城市防洪排涝、水环境监测、地下水观测等方面构建拉萨市水文监测预警体系,为拉萨市的社会经济发展服务.     

地下水功能评价指标选取依据与原则的讨论

地下水功能评价是实现地下水可持续利用和有效保护生态及地质环境的重要基础,而评价的关键是指标的选取。本文在遵循主导性、可度量、可操作、覆盖面广和灵活性原则的基础上,考虑地下水功能的影响因素、表征特征,从地下水系统的驱动、状态和响应因子中筛选出地下水功能评价的指标,从而为地下水功能评价建立了一套行之有效的指标集。     

奎屯河流域南洼地地下水补给特征分析

独山子石油化工基地第二水源地(简称二水源)位于新疆奎屯河流域南洼地,认识和掌握南洼地地下水补给特征是研究和评价独山子石化基地用水保障程度的重要基础。通过南洼地地下水和主要河流的水化学、环境同位素特征分析,对南洼地地下水的补给得到如下认识:二水源西北缘和中部主要接受奎屯河、小巴音沟水的补给,其东南缘主要接受乌兰布拉克沟和乔路特沟地表水的补给;就整个二水源来讲,奎屯河与小巴音沟的补给是主要的。     

小波分析在天然伽玛测井地质解释中的应用

在分析天然伽玛测井数据的信息特点和小波多分辨率分析原理的基础上,用小波多分辨率分析天然伽玛测井数据,消除其中的统计涨落等噪声干扰及提取天然伽玛放射性强度在不同沉积岩地层中分界标志特征和不同岩性中的变化特征,以提高应用天然伽玛测井资料进行地层划分及岩性识别的准确性和有效性.     

Elasto-Plastic Analysis of Tubular Joints of Offshore Platforms by Finite Element Method

The plastic node method is reformulated by the variational principle and is applied to elasto-plastic finite element analysis of tubular joints, eventually including the effect of internal and external gussets, stiffener rings, etc., if necessary. Four different joints are studied here in detail for the elasto-plastic behavior, the strain at the hot spot, the strain concentration factor around the intersection line, and the propagation of the plastic region with loading up to collapse in order to determine the ultimate strength, safety factor, and development of the plastic field. The present results are in good agreement with the experimental results.