北京风沙若干问题的讨论     

陈广庭  贺大良  宋锦熙  关有志 《地理研究》1988,7(3):17-26

本文在实地调查研究的基础上提出对北京风沙一些问题的看法:1)北京风沙物质来源为本地超沙,尘的来源复杂,以外来成分最多;2)分析35午风沙资料得出这些年北京平原风沙趋于成少。  相似文献   

THERMAL EFFECTS OF BUILDING＇S EXTERNAL SURFACES IN CITY——Characteristics of Heat Flux into and out of External Wall Surfaces     

ZHANGYi-ping HEYun-ling LIUYu-hong MAYou-xin LIYou-rong DOUJun-xia 《中国地理科学(英文版)》2004,14(4):343-349

This study examined the thermal effects of building‘s external wall surfaces, using observational data of spatial-temporal distribution of surface temperature, air temperature, and heat flux into and out of external surface. Results indicate that external wall surface temperature and nearby air temperature vary with the change of orientation, height and season. In general, the external wall surface temperature is lower near the ground, and is higher near the roof, than nearby air temperature. But north wall surface temperature is mostly lower than nearby air temperature at the same height; south wall surface temperature during the daytime in December, and west wall surface temperature all day in August, is respectively higher than nearby air temperature. The heat fluxes into and out of external wall surfaces show the differences that exist in the various orientations, heights and seasons. In December,south wall surface at the lower sites emits heat and north wall surface at the higher sites absorbs heat. In April, all external wall surfaces, emit heat near the ground and absorb heat near the roof. In August, west wall surface all day emits heat, and other wall surfaces just show the commensurate behavior with that in April.  相似文献   

农田生态系统中重金属的积累积循环     

穆从如  夏增祿  李森照  孟维奇  沈瑞珍  何瑞珍 《地理研究》1986,5(3):76-81

本文通过对北京东郊高碑店地区污染农田的调查研究,探讨了重金属在农田生态系统中的积累和循环,计算出重金属在区域环境中的输入输出量,说明本区仍处于重金属积累状态,为防治农田环境污染,提出了停止施用污水处理厂的晾干污泥,减少灌溉污水中的重金属含量等保护性措施。  相似文献   

疏散星团M11的维里质量     

赵君亮  何燕萍 《中国天文和天体物理学报》1987,(4)

对疏散星团进行统计研究时,场星的混淆可能是一个严重问题,必须认真对待。本文详细讨论了在估算疏散星团维里(Virial)质量时,正确利用成员概率的重要性。分析表明,只有利用大概率的成员星才能得到合理的星团Virial质量。重新计算后M11的Virial质量为5094μ_⊙,与直接观测到的光度质量的最新结果(4671μ_⊙)符合得很好,维里系数为0.9。  相似文献   

地球物理测井数据格式及面向对象的数据读取   总被引：1，自引：0，他引：1  

李河  王祝文  李舟波  丁永浩 《物探与化探》2005,29(2):174-178

在进行地球物理测井数据处理或解释软件开发时,只有知道所处理的测井数据的格式,才能正确地进行读取、格式转换、数据处理以及绘图等工作。在对ECLIPS 5700数控测井系统XTF文件格式分析的基础上,基于内存映射文件技术,采用面向对象的方法创建了XTF文件数据读取类,实现了大数据量XTF文件数据的快速读取,也可为其它格式测井数据的格式转换和数据处理提供技术参考。  相似文献   

Gas formation mechanism of marine carbonate source rocks in China   总被引：5，自引：1，他引：4  

ZHAO Wenzhi  WANG Zhaoyun  HE Haiqing  ZHANG Mingjie  WANG Hongjun  WANG Yunpeng & QIN Yong . Research Institute of Petroleum Exploration & Development  PetroChina  Beijing  China  . PetroChina Exploration & Production  Beijing  China  . Department of Geology  Lanzhou University  Lanzhou  China  . Guangzhou Geochemical Institute  Chinese Academy of Sciences  Guangzhou  China  . China University of Mining  Technology  Xuzhou  China 《中国科学D辑(英文版)》2005,48(4):441-453

It has been proven in exploration practice that thecarbonates in China not only can generate hydrocar-bons, but also form commercial reservoirs. The car-bonates are different from clastic rocks in view of theirdeposition environment as well as their sedimentaryand diagenetic processes. Therefore, the evaluationcriteria and hydrocarbon generation mechanism forcarbonates can not be the same as that for clasticrocks, and it is important to establish a special hydro-carbon generation mechanism and…  相似文献   

<Superscript>40</Superscript>Ar/<Superscript>39</Superscript>Ar chronology and geochemistry of high-K volcanic rocks in the Mangkang basin,Tibet     

Huihua?Zhang  Huaiyu?He  Jianghai?WangEmail author  Guanghong?Xie 《中国科学D辑(英文版)》2005,48(1):1-12

Our two newly obtained high-quality ⁴⁰Ar/³⁹Ar ages suggest that the high-K volcanic rocks of the Lawuxiang Formation in the Mangkang basin, Tibet were formed at 33.5 ± 0.2 Ma. The tracing of elemental and Pb-Sr-Nd isotopic geochemistry indicates that they were derived from an EM2 enriched mantle in continental subduction caused by transpression. Their evidently negative anomalies in HFSEs such as Nb and Ta make clear that there is an input of continental material into the mantle source. The high-K rocks at 33.5 ± 0.2 Ma in the Mangkang basin may temporally, spatially and compositionally compare with the early one of two-pulse high-K rocks in eastern Tibet distinguished by Wang J. H. et al., implying that they were formed in the same tectonic setting.  相似文献   

ENERGY BALANCE IN 40－50 DAY PERIODIC OSCILLATION OVER THE ASIAN SUMMER MONSOON REGION DURING THE 1979 SUMMER     

He Jinhai  T. Murakami  T. Nakazawa 《大气科学进展》1987,4(1):66-73

Based on calculations of data from FGGE Level III b, a discussion is made of the energy balance in the 40－50 day periodic oscillation over the Asian monsoon region during the 1979 summer. It is found that the main source of 40－50 day periodic perturbation is the monsoon region extending from central South Asia to Southeast Asia. In the upper layer over the North Pacific subtropical area (10－20oN, 150oE－150oW) pres-sure work turns into kinetic energy that maintains 40－50 day periodic perturbation associated with the variation in position and intensity of the mid-Pacific trough. The mean energy budget in the three-dimensional space (0－30oE, 30oE－150oW, 100－1000 hPa) indicates that the 40－50 day periodic perturbation transports kinetic energy to a seasonal mean and a transient perturbation wind field.  相似文献   

Zonal propagation of kinetic energy and convection in the South China Sea and Indian monsoon regions in boreal summer   总被引：7，自引：0，他引：7  

CHEN Longxun  GAO Hui  HE Jinhai  TAO Shiyan & JIN Zuhui .Chinese Academy of Meteorological Sciences  Beijing  China  .Nanjing Institute of Meteorology  Nanjing  China  .Institute of Atmospheric Physics  Chinese Academy of Sciences  Beijing  China 《中国科学D辑(英文版)》2004,47(12):1076-1084

As early as in the 1980s, Chinese scientists hadfirst proposed that there exits two summer monsoonsystems in Asia, namely the East Asian summer mon-soon (EASM) and the Indian summer monsoon(ISM)[1-4]. The two monsoon systems are quite dif-ferent in characteristics. Since then, such issue andconclusion had been documented and approved by alot of studies in the past two decades, and was appliedin the guideline of the South China Sea summer mon-soon experiment (SCSMEX), which was undertak…  相似文献   

Environmental impact of drainage of Dianzi Iron Mine on the groundwater system of the Dawu Water Supply Base   总被引：1，自引：0，他引：1  

He?KeqiangEmail author  Xu?Guangming 《Environmental Geology》2004,45(8):1131-1136

Due to growing water extraction for industry and agriculture, the Dawu Water Supply Base, in the east of Zibo, China, has been in a state of serious over-extraction. It will also be affected by the deep drainage of the Dianzi Iron Mine, which will be exploited in 2005. As to the environmental impact on the groundwater system of the Dawu Water Supply Base is concerned, this paper makes a systematic study about the influence of the mine draining on the water-supply environment of the Dawu Water Supply Base by using the numerical model of groundwater system. The result shows that the groundwater level will have an additional drawdown of 1.2–1.8 m/yr by the mine draining alone. The numerical analysis results indicate that the optimal model for determining the best extraction plan is the solution for the contradiction between water supply and water drainage.  相似文献