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141.
142.
Analyses of trace elements of the Lower Palaeozoic carbonate rock strata in Beijing show that the contents of As, Hg, F increase from primary carbonate rocks to weathered carbonate rocks and from primary carbonate rocks to the soil coexisting with carbonate rocks, but the distribution regularity of S is not obvious. In the whole weathered stages, the sorption of As is mainly affected by Fe2O3. In soil Fe2O3 is also the main affecting factor of Hg enrichment. The main existing forms of Hg in primary carbonate rocks should simply be physical adsorption, coprecipitation and false isomorphous form between surface of carbonate rock and Hg. In soil the enrichment of F has little relationship with sul-fides and Fe2O3. In primary carbonate rocks, F is mainly absorbed by sulfides and clay minerals, etc. Weathered samples have closer genetic relationships with primary carbonate rocks. This also implies that weathered carbonate rocks have the close existing forms to that of primary carbonate rocks. In primary carbonate rocks FeS2 and FeS are the main forms of S, and sulfides have fixation effect on some heavy metals, whereas in weathered carbonate rocks and soil the fixation effect is weakened. 相似文献
143.
144.
Numerical simulation for the coupling effect of local atmospheric circulations over the area of Beijing,Tianjin and Hebei Province 总被引:8,自引:0,他引:8
ShuHua Liu ZhenXin Liu Ju Li YinChun Wang YanJun Ma Li Sheng HePing Liu FuMing Liang GuoJun Xin JianHua Wang 《中国科学D辑(英文版)》2009,52(3):382-392
Using the model system MM5.V3 and multi-layer grid nesting technique, we have done a multi-scale numerical simulation over
the area of Beijing, Tianjin and Hebei Province to analyze the temperature and wind field there and study its local circulations.
The results show a coupling effect of Urban Heat Island Circulation (UHIC), Mountain Valley Breeze (MVB) and Sea Land Breeze
(SLB) occurs in this area when the synoptic system is weak. The SLB can penetrate deep into the mainland for about 200 km
when it is blooming. MVB can extend to south and cover almost the whole plain area in Beijing. Both MVB and SLB are diurnal
periodical; meanwhile the phase of MVB drops behind that of SLB for about six hours. As a local circulation, the UHIC weakens
the two circulations above, and it also has a diurnal period. As a result, the coupling effect of circulations reveals not
only different features in spring-summer period and autumn-winter period in a year but also the difference between early morning
to noonday and afternoon to night in a day. We noted the diffusion of contamination over the area around Beijing, and found
the steady presence of a transport routine of contamination over North-China throughout the year caused by the Coupling Effect
mentioned above. This find is important for studying the environment pollution in this area.
Supported by Central Public Welfare Special Fund Program for the Institute and Higher Education (Grant No. IUMKY200701), Public
Welfare Special Fund Program (Meteorology) of China Scientific and Technological Ministry (Grant Nos. CYHY20080620, CYHY200706004),
Spread New Technology Program of China Meteorological Administration (Grant No. CMATG2007M15) and Urban Meteorology Scientific
Research Fund Program of the Institute of Beijing Urban Meteorology, China Meteorological Administration (Grant No. UMRF200702) 相似文献
145.
Gravitational wave(GW)signals from compact binary coalescences can be used as standard sirens to constrain cosmological parameters if their redshift can be meas... 相似文献
146.
147.
通过广泛的网上资料搜集、分析和整理分类,为广大水文地质及相关行业工作者介绍了英特网上的水文地质信息资源,主要有与水文地质有关的大学、科研机构、电子期刊、虚拟图书馆、虚拟实验室和链接站点的最新获取途径。 相似文献
148.
从沙埝油田地质条件和地面条件的复杂性出发,在该油田产能建设中针对性地应用了石油勘探开发综合技术。重点介绍了三维地震处理解释一体化技术、储层横向预测技术、油藏工程研究技术的应用及取得良好的效果和显著经济效益的情况。说明多学科相互渗透的综合技术是油田发展的重要途径。 相似文献
149.
—In this paper,the second-order perturbation method in frequency domain is used to calculateRAO and spectra of motion and mooring line tension of a turret-moored tanker in ballast condition.Thecalculated results are compared with corresponding experiment results.In the experiment the wave head-ing is 180°,and the wave spectra is the P-M spectrum and white noise spectrum.In the theoretical calcu-lations,the damping coefficient of slow oscillation of the tanker is determined on the basis of the dampingobtained from a test of irregular waves where the mooring system is replaced by a nonlinear spring withnonlinear stiffness similar to that of the mooring system.From the comparison between theoretical calcula-tions and experimental results,it can be found that the theoretical results obtained by the second-orderperturbation method in frequency domain are in good agreement with the experimental results,indicatingthat the damping coefficient of slow oscillation of the tanker required in frequency domain calcu 相似文献
150.
利用T213 1°×1°和欧洲中心实时资料,对2007年4月l~3日四川盆地区域性寒潮天气过程的环流背景及影响系统进行了分析,结果表明:500 hPa乌拉尔山到贝加尔湖以东为宽广深厚的低压带,地面上巴湖附近为冷高压,此冷高压在500 hPa脊前西北气流的引导下东移南压,是造成此次寒潮大风天气的主要原因;而且低空急流也对降温有一定的作用. 相似文献