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991.
DOU Suzhen SUN Zhaocai CAO Ying MA Yumei ZHANG Jingfu LIU Guicheng KOU Xiaoyan Environmental Protection Monitoring Station of Taian City Tai ''an Shandong Environmental Protection Bureau of Dongping County Dongping Shandong 《《地质学报》英文版》2000,74(2):329-333
The Hydrobios in Dongping Lake, Shandong Province, mainly includes phytoplankton, zooplankton, benthic animals, fishes and hydrophytic vascular plants. Nitrogen and phosphorus are the restrictive factors for the growth and propagation of hydrophyta, therefore the key to the prevention and control of eutrophication in lakes lies in the control of the contents of the two elements in the water. Artificial fishing of algae can reduce the concentrations of trophic substances such as nitrogen and phosphorus in the water bodies, and biological measures may decrease the contents of these trophic substances in the bottom sediments and the water bodies, thereby playing an active role in modifying the eutrophication of the lake. 相似文献
992.
FENG Weiheng FENG Yun Shanghai Gamma Ray Technology Co. Ltd. Laohumin Rd. Shanghai 《《地质学报》英文版》2000,74(3):685-691
The main reason why the application of nuclear technology in petroleum exploration has not yet been accepted by most exploration workers is that they are not clear about the homologous distribution features of oil and gas fields and radioactive radiation. The authors hold that the disequilibrium of uranium, radium and radon as a natural radioactive series is the basic feature in the use of this technology in petroleum exploration. The invention Gamma-ray Spectral Measurement of the Equilibium Coefficient Kp and Its Embodiment of the senior author now can readily solve that problem and replace the impedient measure of normalization of uranium and potassium to thorium that had to be proposed before. Application of this impedient measure has some limitations. In areas where the surface is covered by beach or river sands, thorium minerals such as monazite may be concentrated by placering. This could result in local thorium highs that would yield local uranium and potassium lows after normalization to thoriu 相似文献
993.
This paper retrieves the yearly and monthly mean 0.75μm aerosol optical depth(AOD)of 41A-class solar radiation stations over China from 1979 to 1990,and analyzes the spatial andtemporal distribution of AOD over China mainland.The data employed are daily direct solarradiation and sunshine duration,as well as the TOMS version-7 ozone observation data in the sametime.The results indicate that the Siehuan Basin is the largest center of yearly mean AOD overChina.and the other two larger centers lie in Wuhan City and the South Xinjiang Basin,separately.AOD values are also relatively larger in the middle-and-lower reaches area ofChangjiang River.Shandong Peninsula and coastal area of Guangdong Province:while in YunnanProvince,coastal area of Fujian Province.most parts of Northwest and Northeast China,AODvalues are relatively smaller.The distribution of AOD varies with different months.In most partsof China.the maximum of AOD occurs in spring season;but the minimum varies in differentregions,From 1979 to 1990.in the Qinghai-Xizang Plateau,West Siehuan Basin,North GuizhouProvince.most areas of the middle-and-lower reaches of Changjiang River,Shandong Peninsulaand west part of South Xinjiang Basin.AOD shows an increasing trend.But in Northeast China,most part of Northwest China,Yunnan-Guizhou Plateau,western Guangxi Region and the coastalareas of East China,AOD shows decreasing tendency.Generally,the seasonal variationcharacteristics of AOD in China can be classified into four typical models,i.e.,mono-modal typesA and B,bimodal and Poly-modal. 相似文献
994.
松辽盆地三肇地区上生下储“注入式”成藏机制 总被引:71,自引:1,他引:70
三肇地区位于松辽盆地中部,是一个继承性深断陷-坳陷区。在上部坳陷中沉积了一套“上泥下砂”的地层。巨厚泥岩段底部的青山口组一段黑色泥岩是本区最主要的生油岩,在嫩江湖(Campanian)末期进入生油门限,明水期(Maastrichtian)末期一早第三纪晚期(Chattian)达到生烃、排烃高峰。在上覆大段泥岩封闭作用下,青一段地层形成超压,迫使油气向下排泄到下伏的扶扬油层储层。同时期,大量断开青一 相似文献
995.
川西北马脑壳金矿床流体包裹体研究及对成矿条件的制约 总被引:8,自引:1,他引:7
川西北的马脑壳金矿床为一赋存于三叠系碎屑岩、碳酸盐岩系的大型微细浸梁型金矿床,通过详细野外地质调查和室内综合研究,可将矿床的热液成矿作用划分为四个阶段,应用均一法测得:I、II、III、IV阶段的成矿温度分别为175~230℃,179~255℃,157~207℃,120~200℃,峰值分别为190~210℃,200~230℃,170~190℃,130~170℃,盐度变化范围,I、II、III、IV 相似文献
996.
“诱发前震”预测效能评价 总被引:1,自引:0,他引:1
“诱发前震”现象在区域地震活动中较普遍,据此提出A-F-B图象预报方法,以区域大震后短时间内发生的小震为预报因子,判断以后大震的位置并推测其震级与时间。为了检验该方法的实用性,统计了我国西南地区1970—1983年和华北地区1966—1984年的地震资料,对其预测效能做了统计评价。评分采用W值与R值。其中:W=1-(漏报率+虚报率);R=报对地震占有面积/应预报地震占有面积-预报区占有面积/研究区总面积。结果为W与R值都大于0.5,波动在0.5~0.8之间;并计算出各种不同预报参量的频数概率分布,给出了单次预报在取不同空间与时间范围的信度。 相似文献
997.
考虑土-结构相互作用的高层建筑抗震分析 总被引:17,自引:0,他引:17
本文采用通用有限元程序ANSYS,针对上海地区一例土-箱基-高层建筑结构进行了三维有限元分析,计算中土体的本构模型采用等效线性模型,利用粘一弹性人工边界作为土体的侧向边界,并研究了土体边界位置、土性、基础埋深、基础形式以及上部结构刚度等参数对动力相互作用体系动力特性及地震反应的影响。 相似文献
998.
Xu Chunrong Lin Yunfang Lu Guifang Zhao Ming Li Shengxiang Gou Xianbin Yu Jingzhong and Zeng XiaopingInstitute of Crustal Dynamics CSB Beijing China Institute of Geophysics CSB Beijing China Seismological Bureau of Yunnan Province Kunming China Seismological Office of Chongqing Municipality Chongqing China 《中国地震研究》1998,(4)
Many earthquakes occurred during the period 1994 -1996 in Sichuan and Yunnan Provinces, Southwest China. Taking the process of the initial main phase recovery phase of the magnetic storm as the process of load-unload response of the geomagnetic field to the solar wind, we have estimated and analyzed the distribution in time and space of the load-unload response ratio P(z) of the storm time disturbance daily variation of the vertical component Z of the geomagnetic field at ten stations in Southwest China. We found that the area with high ratio P(z) was just the area where moderately strong earthquakes would occur from 44 days to 15 months later. The relationship between the high ratio P(z) and weather disasters in both seismic and non-seismic areas is discussed briefly. 相似文献
999.
上海市气象局预报组数值预报小组 《大气科学》1976,(1):16-20
自1975年9月16日起我们制作三层业务数值预报,每天根据08时(北京时,下同)高空资料作一次直到72小时的700毫巴、500毫巴、300毫巴的环流形势预报。用的是DJS-6电子计算机,该机平均运算速度5万次(浮点)—7万次(定点),内存容量3万2千个48位二进制单元。 上述业务数值预报,在每天14:05时由控制台打字机打入电传命令后,调度程序即行控制自高空气象电报纸带输入至数值预报图输出的自动化过程。14:10时二盘纸带输 相似文献
1000.