An experimental study on seismic responses of multifunctional vibration‐absorption reinforced concrete megaframe structures

Two models are tested on a shake‐table. One of the models is a normal reinforced concrete megaframe structure and the other is a multifunctional vibration‐absorption reinforced concrete megaframe structure in which the laminated rubber bearings are placed between the major frame and the minor frames. Two earthquake motions (the El Centro wave and the Taft wave) are used during the test. This paper presents the dynamic characteristic, the seismic responses and the failure mechanism of these two models under varying peak acceleration levels for each of the earthquake motions. The test results demonstrate that the aseismic behavior of a multifunctional vibration‐absorption reinforced concrete megaframe structure is much better than that of a normal reinforced concrete megaframe structure. Copyright © 2003 John Wiley & Sons, Ltd.     

数值预报产品在夏季持续高温预报中的释用

利用 1999～ 2 0 0 2年 6～ 8月 96～ 192h日本数值预报产品 85 0hPa气温与吉林省的日平均气温、阶段性高温及极端最高气温 (长春市 )资料 ,通过线性分析 ,找出了日本数值预报产品的 85 0hPa气温与吉林省地面日平均气温、阶段性高温及极端最高气温的对应关系 :吉林省 6～ 8月日平均气温在 96～ 192h的 85 0hPa日本数值预报长春站日平均值上加 6 6～ 4 1℃ ,6～ 8月的极端最高气温在相应的日本数值预报产品上加 9 3～ 13 0℃。     

北京地区两次沙尘(暴)天气过程对比分析

通过对 2 0 0 0年 4月 6日和 4月 9日北京地区两次沙尘 (暴 )天气过程的对比分析认为 :蒙古气旋型和不伴有气旋的西北槽型所造成的北京沙尘天气的严重程度不同 ;沙源地区中低层较强上升运动的主要作用是将当地沙尘垂直输送到空中 ,然后在70 0hPa较强西北气流的引导下将卷起的沙尘水平输送到下游地区 ;不稳定层结又加强了沙尘天气 ;沙尘暴区上空z 螺旋度分布的特征是高层为负值 ,低层为正值 ,对流层中低层螺旋度正的大值区与卫星云图显示的沙尘暴区具有较好的一致性 ,对沙尘暴的预报有一定的指示意义     

鹤壁市雷暴短时监测和临近预报流程

利用卫星云图数字化资料、雷达探测和雷电定位探测资料对雷暴天气进行短时监测 ,并与多种短期预报方法集成 ,建立时效为 3～ 6小时的雷暴临近预报流程 ,从而达到预测强对流天气之目的。     

CASIOfx-4500PA型计算器在矿床地质勘查中的应用

CASIOfx-4500PA型计算器为可编程、大容量的科学计算器。通过对地质计算中面积计算、槽坑钻样品厚度计算、钻孔弯曲度修正值计算的原理阐述，简化了计算程序，提高了计算效率。     

网络安全加密技术在基于IIMS信息管理系统中的应用

介绍网络加密技术和DES(对称密钥体制)加密算法，分析了选用DES数据加密标准对网络数据流加密的可行性和优越性，研究了JAVA安全结构和在B／S模式下APPLET与SERVLET之间的通信机制，最后基于该模式给出了一个在四川省图书馆综合管理系统中的应用实例。     

基于RS和GIS的农业土地利用污染分析

农业已被确认为地表和地下水最主要的非点源污染源，而土地利用方式又是影响非点源污染的关键性因素。大规模的土地利用与开发、化肥与农药用量的增加、规模养殖业的发展、生活垃圾的增加等，这些非点污染源严重威胁水体质量，进而影响到人们的生活。为了更好地预测和控制、管理非点源污染，必须研究其负荷定量化问题。本文从以上几方面入手，讨论了非点源污染与农业土地利用方式之间的关系，利用组件GIS技术，以网格为评价单元，实现非点源污染负荷的定量计算及可视化分析。文章最后以上海市松江区作为研究区域，对该区的污染情况进行了分析。     

Estimation of ocean primary productivity and its spatio-temporal variation mechanism for East China Sea based on VGPM model

According to calculation results of ocean chlorophyll concentration based on SeaWiFS data by SeaBAM model and synchronous ship-measured data, this research set up an improved model for CaseⅠand CaseⅡwater bodies respectively. The monthly chlorophyll distribution in the East China Sea in 1998 was obtained from this improved model on calculation results of SeaBAM. The euphotic depth distribution in 1998 in the East China Sea is calculated by using remote sensing data of K490 from SeaWiFS according to the relation between the euphotic depth and the oceanic diffuse attenuation coefficient. With data of ocean chlorophyll concentration, euphotic depth, ocean surface photosynthetic available radiation (PAR), daily photoperiod and optimal rate of daily carbon fixation within a water column, the monthly and annual primary productivity spatio-temporal distributions in the East China Sea in 1998 were obtained based on VGPM model. Based on analysis of those distributions, the conclusion can be drawn that there is a clear bimodality character of primary productivity in the monthly distribution in the East China Sea. In detail, the monthly distribution of primary productivity stays the lowest level in winter and rises rapidly to the peak in spring. It gets down a little in summer, and gets up a little in autumn. The daily average of primary productivity in the whole East China Sea is 560.03 mg/m2/d, which is far higher than the average of subtropical ocean areas. The annual average of primary productivity is 236.95 g/m2/a. The research on the seasonal variety mechanism of primary productivity shows that several factors that affect the spatio-temporal distribution may include the chlorophyll concentration distribution, temperature condition, the Yangtze River diluted water variety, the euphotic depth, ocean current variety, etc. But the main influencing factors may be different in each local sea area.     

西风带研究动态

本文较为详细地介绍了影响我国气候的重要因子——西风带的一些国内外最新研究动态,这些研究动态和研究成果将对山西省的气候研究起到积极作用。