Climatic characteristics of summer high temperature and assessment methods in the large cities of North China     

ZHANG Shangyin  ZHANG Dekuan  WANG Shourong  SONG Yanling 《地理学报》2006,16(1):13-22

Based on the high temperature data of June to August in 1961-2000 in North China, the high temperature weather processes are investigated, and a more complete data set for severe high temperature processes is created. The climatic characteristics of adverse high temperature weather in Beijing, Tianjin, Shijiazhuang, Jinan and Taiyuan are analyzed respectively. The major features of the East-Asia Subtropical High and Transformed Continental High are discussed. The outcomes indicate that the influence of both East Asia Subtropical High and Transformed Continental High on these weather events varies, by a larger margin, from one city to another over North China and they are also closely related to the relative humidity. It is found that the behaviours of East-Asia Subtropical High and Transformed Continental High are the major important systems that give rise to the summer high temperature weather over the region. Based on these findings, the 5-day, 10-day and monthly assessment models for such high impact events have been developed. The assessment outcomes prove to be useful in assessing severe high-temperature events in major cities of North China.  相似文献   

Geotechnical Properties of Low Calcium and High Calcium Fly Ash   总被引：1，自引：0，他引：1  

Sarat Kumar Das  Yudhbir 《Geotechnical and Geological Engineering》2006,24(2):249-263

In this paper, a comparative study has been made for physical and engineering properties of low calcium and high calcium Indian fly ash. The grain size distribution of fly ash is independent of lime content. Fly ash particles of size >75 μm are mostly irregular in shape whereas finer fractions are spherical for low calcium fly ash. For high calcium fly ash, chemical and mineralogical differences have been observed for different size fractions. Compared to low calcium fly ash, optimum moisture content is low and maximum dry density is high for high calcium fly ash. Optimum moisture content is directly proportional and maximum dry density is inversely proportional to the carbon content. The mode and duration of curing have significant effect on strength and stress–strain behavior of compacted fly ash. The gain in strength with time for high calcium fly ash is very high compared to that of low calcium fly ash due to presence of reactive minerals and glassy phase.  相似文献   

Groundwater and highways interaction: past and present experiences of highway construction in Slovenia     

Mihael Brencic 《Environmental Geology》2006,49(6):804-813

During the planning, designing, construction, operation and maintenance of highways, groundwater can be of important environmental and constructional constraint that can significantly influence the safety operation of traffic and of big influence on the operational costs of highways. To classify and conceptualize the relation between groundwater and highways, three important groups of problems can be determined: groundwater protection from highway influences, protection of highway from groundwater and economic use of groundwater for highway operation. In the present study, groundwater management strategies are represented during all life cycles of highways. Greater emphasis is given to groundwater protection and field hydrogeological investigations for proper groundwater management related to the highway. The approach adopted in Slovenia and the role of hydrogeology is given as an illustration.  相似文献   

层状介质高频电磁场响应及位移电流影响     

郑圣谈  曾昭发  王者江 《吉林大学学报(地球科学版)》2006,(Z1)

所讨论的电磁场频率介于传统的低频电磁法和雷达频率之间。在这个频率范围内,传导电流和位移电流都是不可忽略的。采用高密度采样算法计算水平层状磁偶线圈模型的电磁响应,通过对归一化的电磁响应在不同地电情况的模拟,比较分析了高频电磁场响应特征以及位移电流对高频电磁响应的贡献。  相似文献   

Practical Research of IKONOS-2 Geopositioning and Its Accuracy in Tibet of China     

CHENChujiang LIDeren ZHUQing 《地球空间信息科学学报》2005,8(1):33-38

This paper presents the studies of the refining of IKONOS-2 RPC, the transform of the datum, the mode of the control point distribution and the method of IKONOS stereo triangulation, so that IKONOS imagery can be used to collect the precise geospatial data and produce the large scale map. The transform between the IKONOS-2 image space and the national coordinate system based on the RPC have been developed, and the results of block adjustment with various control schemes in a practical project near Himalayas have been examined and analysed. The encouraging results of high positioning accuracy have been obtained.  相似文献   

黄骅坳陷北大港构造带古近系沙河街组高分辨率层序地层格架及其对储层非均质性的控制   总被引：9，自引：1，他引：9  

范乐元  朱筱敏  宋鹍  朱之春  谢楠 《地层学杂志》2005,29(4):355-361,367

陆相湖盆层序的发育是在湖盆蓄水量周期性变化的条件下实现的。层序发育过程实际上是基准面旋回变化过程中湖泊冲刷沉积作用彼此消长的过程。北大港构造带古近系沙河街组可划分为2个长期基准面旋回、8个中期基准面旋回和43个短期基准面旋回。在等时地层格架内,基于基准面变化过程中的沉积响应及其伴生的可容空间变化的分析,探讨了基准面旋回变化与储层展布及储层非均质性之间的相关关系:基准面旋回的升降变化对储层的非均质性、空间展布以及有利储层的分布等均具有明显的控制作用;短期基准面旋回控制储层砂体内部的非均质模式,中长期基准面旋回控制了储层砂体的层间非均质性特征;在中长期基准面低位处,尤其是在基准面旋回的转换点处,储层发育良好,砂体厚度、展布面积均较大,物性相对较好;而在中长起基准面较高位处,则出现相反的储层特征。  相似文献   

早涝碱咸综合治理与生态环境良性循环     

方生陈秀玲  范振铎万宝林 《地下水》2005,27(1):1-5,9

华北平原东部淡水资源短缺，旱涝碱成灾害限制了农业生产的可持续发展。海河的治理，解决了排洪排涝排咸出路。春季开发利用地下水包括微咸水和半咸水抗旱灌溉。夏季利用伏雨洗盐排咸，增大降雨入渗，减少径流流失，防治渍涝灾害，把降雨转化为地下水资源。秋冬引蓄河水，回灌地下水补源。以土壤与潜水的地层空间作为调节大气降水、土壤水、地下水、地表水的地下水库，以调控地下水埋深在临界动态为指标，最大限度地把时空分布不均的天然降雨转化为可持续利用的水资源。地表水地下水联合运用，促使水资源采补平衡，降雨灌溉淋洗脱盐强于干旱蒸发积盐过程，地下水淡化强于矿化过程。实现旱涝碱咸综合治理，水土资源可持续利用，经济社会可持续发展，生态环境良性循环。  相似文献   

论运城市地下水超采与保护策略     

卢莉莉 《地下水》2005,27(3):154-155

本文论述了2002年运城市地下水超采状况及其引起的环境地质等一系列问题.并遵循可持续发展的思想,提出了地下水资源保护的几点意见.  相似文献   

北京市地下水动态监测示范工程的建设和应用     

杨忠山  薛伟  周东 《地下水》2005,27(5):384-387

北京市地下水动态监测示范工程是北京市科委的重大项目,从1999年开始建设,到2004年4月全面完成.本文详细介绍了该项目的建设及开发内容,以及在北京市地下水动态监测工作中的应用情况.  相似文献   

山西省地下水资源开发利用的对策     

狄丕勋 《地下水》2005,27(6):466-469

本文基于可持续发展的思想,论述了山西省地下水开发利用现状及存在的问题,分析了地下水的开发利用潜力,提出了地下水资源开发、利用应采取的对策.  相似文献