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251.
利用江苏数字地震台网1999年1月1日-2008年12月31日3个以上子台记录到的约1 500条地震,以台网的平均震级为标准震级,详细分析了江苏数字台网子台的震级偏差原因,结果显示:①在震中距较小时(100 km),子台测定的震级偏小,在100 km△250 km范围内,震级偏差基本为零;②子台测定的震级偏差存在地域分布特征,随方位角显示趋势性变化,地区邻近的子台之间变化特征相近或相似;③江苏数字台网子台台基类型中松散沉积对震级影响最大,偏差均为正值,最大偏差约0.3级,灰岩类型的台基对震级测定影响最小,几乎为零。 相似文献
252.
介绍了基于Web的流动地震监测数据库查询系统的开发背景和目的,描述了数据库查询系统的设计和实现过程。该系统借助Internet/Intranet网络,以B/S(浏览器/服务器)体系结构作为基础架构,采用WAMP集成化软件开发,具有系统加密、数据查询、数据维护、数据导出和资料下载等功能。 相似文献
253.
油页岩综合利用对周围环境的影响——以抚顺矿区为例 总被引:3,自引:0,他引:3
世界能源日益减少的局面为油页岩的开发应用带来广阔的前景,但油页岩工业所带来的环境影响亦不容忽视。以抚顺油页岩为例,从油页岩综合利用和油页岩工业对环境的影响等方面系统讨论了在我国发展油页岩工业时,如何本着节约能源、保护环境、实现可持续发展的观念,利用现有先进技术,科学发展油页岩工业,降低生产过程中的固、液、气污染物对环境的危害。 相似文献
254.
通过对江苏地区及南黄海海域历史地震资料特点分析,将研究区历史地震类型分为相对安全类和相对危险类,并对地震类型的统计结果、地理分布特征及构造进行探讨. 结果表明:① 江苏及南黄海地区绝大多数中强以上历史地震类型为相对安全类,仅有13.8%的中强以上历史地震为相对危险类;② 江苏陆地、长江口以东海域和南黄海北部坳陷地区以相对安全类地震为主,苏中沿海南黄海海域地震类型分布较为复杂,相对安全类和相对危险类地震类型比例基本相当;③ 研究区历史地震类型统计结果和空间分布特征与现代地震序列类型实况非常吻合,反映本区地震活动具有继承性的特点.研究结果可以作为江苏省地震应急工作中震后早期趋势判定的参考依据. 相似文献
255.
With the floating structures pushing their activities to the ultra-deep water,model tests have presented a challenge due to the limitation of the existing wave basins.Therefore,the concept of truncated mooring system is implemented to replace the full depth mooring system in the model tests,which aims to have the same dynamic responses as the full depth system.The truncated mooring system plays such a significant role that extra attention should be paid to the mooring systems with large truncation factor.Three different types of large truncation factor mooring system are being employed in the simulations,including the homogenously truncated mooring system,non-homogenously truncated mooring system and simplified truncated mooring system.A catenary moored semi-submersible operating at 1000 m water depth is presented.In addition,truncated mooring systems are proposed at the truncated water depth of 200 m.In order to explore the applicability of these truncated mooring systems,numerical simulations of the platform’s surge free decay interacting with three different styles of truncated mooring systems are studied in calm water.Furthermore,the mooring-induced damping of the truncated mooring systems is simulated in the regular wave.Finally,the platform motion responses and mooring line dynamics are simulated in irregular wave.All these simulations are implemented by employing full time domain coupled dynamic analysis,and the results are compared with those of the full depth simulations in the same cases.The results show that the mooring-induced damping plays a significant role in platform motion responses,and all truncated mooring systems are suitable for model tests with appropriate truncated mooring line diameters.However,a large diameter is needed for simplified truncated mooring lines.The suggestions are given to the selection of truncated mooring system for different situations as well as to the truncated mooring design criteria. 相似文献
256.
Isotope Tracing and Prospecting Assessment of Gold-Silver Deposits in Zhejiang Province 总被引:1,自引:0,他引:1
Chen Haoshou Xu Butai Department of Earth Sciences Zhejiang University Hangzhou Zhejiang Zhejiang Institute of Geology Mineral Resources Hangzhou Zhejiang Liu Xinzhu 《《地质学报》英文版》1997,71(3):293-304
Three different types of gold and silver deposits in Zhejiang Province(Huangshan gold deposit, Zhilingtou gold-silver deposit and Haoshi silver deposit) showmarked differences in lead and strontium isotopic composition, suggesting three differentsources and geneses of these deposits. The Huangshan gold deposit features low initial Srisotope ratios and low μ values or low content of radiogenic Pb and its ore-forming materialscame primarily from the upper mantle; the Zhilingtou gold-silver deposit shows high initial Srisotope ratios and high μ values or high content of radiogenic Pb and the ore-forming materialswere derived mainly from the upper crust; and the Haoshi silver deposit has its Pb and Srisotope ratios between the above two cases with the ore-forming materials stemming from boththe mantle and the crust. The characteristic Pb isotopic composition may serve as an indicatorfor prospecting for different types of ore deposits. 相似文献
257.
Argentian mercurian gold,golden-yellow in colour,is a variety of native gold containing Ag and Hg,coccurring as hexagonal and tetragonal crystals in hairy,milk-droplet or irregular forms.Its microhardness Hv=91kg/mm^2,equivalent to 3.04on Mons‘scale,and the reflectance is 70.35%(589nm).Chemical analysis gave:Au 56.05-67.33,Ag18.29-31.06 and Hg 10-14.82%,as well as minor Cu.In a few samples Bi or Fe was also detected.The simplified formula is (Au0.52Ag0.36Hg0.09Cu0.02)0.99.X-ray analysis suggests the mineral is of isometric system,with space group=Oh^5-Fm3m,a0=0.40803nm,V=0.06739nm^3,and Z=4.Argentian mercurian gold occurs in a Ag-multimetal deposit at Xiacun,Baiyu County,Sichuan Province,As observed in the mining district,the mineral is distributed along the fissures of the main metallic minerals pyrite,tetrahedrite,chalcopyrite,arsenopyrite,galena,sphalerite,etc.,or in the sulfide veinlets developed in the.fissures of these minerals.Also found in the mineral deposit are native gold,argentite,sulvanite,bournonite,boulangrite,etc. 相似文献
258.
本文根据层序地层学的基本原理,立足东部箕状断陷盆地的特点,以冀中拗陷和二连盆地为重点研究对象,提炼出陆相断陷盆地层序地层学模式,在缓坡带,以风暴浪基面作为“陆架边角”的参照物,层序地层特征相似于海相被动大陆边缘背景;在陡坡带则截然不同,并以湖面与边界断裂的交点取代“陆架边角”,各体系域所含沉积体系与海相模式不尽相同,在盆地形成初期的层序,低水位体系域发育,湖泊消亡以后,主要发育高水位体系域。此外,本文还探索了层序地层与油气赋存的关系,指出富砂的“盆底扇”是今后勘探开发的重要方向。 相似文献
259.
260.
The variations of current circulation, salt intrusion, and vertical stratification under different river flow and wind conditions in the Pamlico River Estuary (PRE) were investigated in this paper using a three-dimensional numerical model. The model was calibrated and verified against water level variation, temperature, and salinity variations during 2003 and 2001, respectively. Eight sensitivity tests were conducted with different river flow and wind conditions specified in the model. Model results show that salinity intruded further upstream under scenarios with low flow, downriver local wind, and remote-wind-caused water level set-up conditions. In contrast, the responses of salinity stratification to different environmental forcing functions were different in different portions of the estuary. Salinity stratification was enhanced under high flow condition at the lower part of the estuary, under upriver wind near the river mouth, under downriver wind at the upstream to middle portion of the estuary, and under remote-wind-caused water level set-up condition at the majority of the estuary except near the river mouth. Model results also show that across-channel wind tended to reduce salt intrusion and salinity stratification in the PRE through increased vertical mixing. 相似文献