中国区域缺水问题的发展趋势与解决对策   总被引：5，自引：0，他引：5  

沈大军 《地球科学进展》1996,11(4):342-349

分析了建国以来我国两个缺水阶段的特点，即第一阶段是由农田灌溉面积快速发展引起的，第二阶段是供水能力增长缓慢造成的；然后根据我国工业发展速度、宜农荒地面积和农田灌溉面积的增长情况，分５个地区对我国２１世纪的水资源需求进行了预测，２１世纪我国的需水量将持续增长，至２０５０年达９５０×１０９ｍ３，但供水发展缓慢，因此我国２１世纪上半叶区域缺水问题严重。最后提出了解决我国区域缺水问题的四条对策，即开源、节流、加强污水处理与扩大资金投入  相似文献   

Comparison of sound speed and attenuation measured in a sandy sediment to predictions based on the Biot theory of porous media   总被引：2，自引：0，他引：2  

Williams  K.L. Jackson  D.R. Thorsos  E.I. Dajun Tang Schock  S.G. 《Oceanic Engineering, IEEE Journal of》2002,27(3):413-428

During the sediment acoustics experiment in 1999 (SAX99), several researchers measured sound speed and attenuation. Together, the measurements span the frequency range of about 125 Hz-400 kHz. The data are unique both for the frequency range spanned at a common location, and for the extensive environmental characterization that was carried out as part of SAX99. Environmental measurements were sufficient to determine or bound the values of almost all the sediment and pore water physical property input parameters of the Biot poroelastic model for sediment. However, the measurement uncertainties for some of the parameters result in significant uncertainties for Biot-model predictions. Here, measured sound-speed and attenuation results are compared to the frequency dependence predicted by Biot theory and a simpler "effective density" fluid model derived from Biot theory. Model/data comparisons are shown where the uncertainty in Biot predictions due to the measurement uncertainties for values of each input parameter are quantified. A final set of parameter values, for use in other modeling applications e.g., in modeling backscattering (Williams et al., 2002) are given, that optimize the fit of the Biot and effective density fluid models to the sound-speed dispersion and attenuation measured during SAX99. The results indicate that the variation of sound speed with frequency is fairly well modeled by Biot theory but the variation of attenuation with frequency deviates from Biot theory predictions for homogeneous sediment as frequency increases. This deviation may be due to scattering from volume heterogeneity. Another possibility for this deviation is shearing at grain contacts hypothesized by Buckingham; comparisons are also made with this model.  相似文献   

双星系统在密林区的测量方法及应用效果分析   总被引：2，自引：0，他引：2  

雷迎春  李大军  王向阳  罗伦才 《测绘通报》2010,(4)

在森林区进行地震勘探测量的主要方法有两种,GPS测量和全站仪常规测量。常规测量主要用于卫星遮挡严重的峡谷地区,但是需要通视条件,这就涉及林木砍伐的问题,这是国家严格控制甚至某些地段是绝对禁止的,充分利用双星系统的各种功能、采用多种作业方式和不同的软件进行解算,尽量避免林木砍伐,既能提高在原始森林中的测量作业效率,又极大限度地保护了森林资源,这也是今后相当一段时间内石油勘探测量的一个重要课题。通过在东北某密集林区的作业情况证明,采用双星系统的多种作用方式既能提高作业速度又能最大限度地避免砍伐林木,同时节约勘探成本。  相似文献   

Research on formation density MWD instrument in engineering geological exploration     

Dajun ZHAO    Guosheng JIANG  Youhong SUN  Junhua ZHENG  Zhuwen WANG .Faculty of Engineering  China University of Geosciences  Wuhan  China.College of Construction Engineering  Jilin University  Changchun  China.College of Geoexploration Science  Technology  China 《东北亚地学研究》2008,11(4):228-231

A high efficiency method is very important in geological survey for a new city in China. Geophysical parameters are Measured While Drilling （MWD）, and these parameters are processed and explained on the ground, so the method can replace conventional engineering geological exploration for drilling rock sample. According petroleum engineering MWD, using the different characters of different rock absorbs γ radial, with the method of storing data in hole and explaining data on the ground, engineering geological exploration formation density MWD is researched. The MWD works stabilized, and the performance is good with precise data.  相似文献   

基于岩石表面位移场的超声波振动下花岗岩损伤特性试验研究          下载免费PDF全文

张程  赵大军  张书磊  周宇 《探矿工程》2021,48(3):39-45

超声波振动碎岩技术作为解决硬岩钻进难题的新方法,其技术可行性受到国内外学者的大量验证,但是对于超声波振动下硬岩破碎机理的认识还存在不足。超声波振动下岩石表面径向响应位移与内部损伤状态存在着必然的联系,本文通过监测岩石在超声波振动过程中表面不同深度处的径向响应位移,利用应力波传播理论从能量耗散角度分析了岩石表面不同深度监测点径向响应位移的时空演化与岩石内部损伤发展的关系,得出超声波振动下岩石损伤主要由振动头高频冲击岩石造成的Hertz锥形环状裂纹和超声波振动交变应力产生的疲劳拉伸裂纹造成的,Hertz锥形环状裂纹的扩展深度为10 mm,疲劳损伤裂纹主要在10~20 mm深度处产生,超声波振动下岩石发生局部宏观破碎前存在着明显的径向响应位移征兆,岩石表面径向响应位移可以作为超声波振动下的破坏判据。本文的研究对于丰富超声波振动下硬岩的破碎机理具有重要意义。  相似文献   

“浣熊”强度变化的环境背景和卫星观测分析   总被引：1，自引：1，他引：0  

李勋  李泽椿  赵声蓉  王勇  赵大军 《气象》2009,35(12):21-29

利用实况观测定位和强度资料、NCEP的1°×1°全球最终分析资料、NOAA周平均1°×1°海温再分析资料和FY卫星水汽图像,分析台风浣熊(0801)的环境背景条件和内核结构演变与强度变化的关系.结果表明:(1)环境风垂直切变增大至10m·s~(-1)左右与南海北部海表温度逐步减小导致最大可能强度不断降低是"浣熊"快速发展过程中断并减弱的重要外部条件;(2)卫星水汽图像显示内核结构存在眼壁破裂和复原现象,该现象精确地反映其强度变化.眼壁破裂(复原)过程导致"浣熊"减弱(增强).  相似文献   

Paleomagnetic results of the Cretaceous marine sediments in Tongyouluke, southwest Tarim     

SHEN Zhongyue  CHEN Hanlin  FANG Dajun  DING Jinghai  ZHANG Shiben  HUANG Zhibin & LI Meng . Department of Earth Sciences  Zhejiang University  Hangzhou China  . Tarim Oil Field Company  PetroChina Company Limited  Korla  China 《中国科学D辑(英文版)》2005,48(3):406-416

Southwest Tarim (hereafter SW Tarim) is one of afew areas that well developed Cretaceous marinesedimentary rocks in China [1]. The Cretaceous marinesediments are stretched in front area along the Tian-shan and Kunlun Mountains. Toward the center ofTarim Basin, the Cretaceous sediments are buried bygreat thickness of Tertiary and Quaternary sedimentswith little exposure. Compared with the Cretaceousterrestrial strata of north Tarim, the Cretaceous marinestrata of SW Tarim continue and d…  相似文献   

Cenozoic paleomagnetic results and phanerozoic apparent polar wandering path of Tarim Block*     

Fang Dajun  Wang Pengyan  Shen Zhongyue  Tan Xiaodong 《中国科学D辑(英文版)》1998,41(2):105-112

New paleornagnetic data from Cenozoic rocks in Tarim enable people to revise the Phanerozoic apparent polar wandering path (APWP) of this block. This modified Tarim APWA is supported by data from other Chinese blocks. On the basis of the APWA, it is concluded that Tarim rode on a plate subducting under the Kazakhstan plate between Carboniferous and Permian time. By the Late Permian, subduction had finished. The APWP also revealed that tectonic evolution of the Tarim was characterized by northern latitudinal displacement during the Paleozoic time, while Tarim remained at relative low latitude (about 20°) until1 Cretaceous.  相似文献   

恩施州富硒区儿童发镉的调查     

邵器行  毛大钧  苏宏灿 《矿物岩石地球化学通报》1998,(2)

恩施州富硒区儿童发镉的调查邵器行（中国地质大学,武汉４３００７４）毛大钧苏宏灿（恩施州卫生防疫站,湖北恩施４４５０００）（恩施州妇幼保健院,湖北恩施４４５０００）关键词镉元素的组合效应儿童富硒区湖北恩施Ｃｄ是对人体有害的微量元素。在铅锌多金属硫化物矿...  相似文献   

冀东金厂峪特大型金矿床的地质地球化学特征和矿床成因   总被引：6，自引：0，他引：6  

秦大军  蔡新平 《地质与勘探》1997,33(5):4-9

金厂峪金矿产于八道河群王厂组，矿体受刘村寨－双沟峪复式向斜控制，成矿与中生代构造作用及岩浆活动有密切关系矿床的形成经历了复式向斜构造的形成，与岩浆活动有关的成矿热液沿构造薄弱带运移；热液蚀变及矿质沉淀。硫，氧，碳，铅同位素数据表明成矿物质来源于深部，与矿床围岩具有不同的属性。  相似文献