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41.
以国家重大产业技术开发专项“西部煤炭资源高精度三维地震勘探技术”项目的由来、意义和总体研究目标为引,概括的介绍了项目依托工程中各个专项技术研究完成情况,并对非均匀介质成像技术、高精度三维地震静校正技术、高密度采集技术、特观技术、岩性反演技术、属性体解释技术等六项重大关键技术取得的突破性进展进行了重点说明。指出随着我国煤炭生产重点的逐步西移,应加强诸如叠前、叠后深度偏移技术的研究,以解决复杂山区三维地震面元内地震反射波散射问题,提高其三维地震勘探精度,为西部煤炭工业做出新贡献! 相似文献
42.
辅助纬度反解公式的Hermite插值法新解 总被引:1,自引:0,他引:1
利用计算机代数系统,推导出了地图投影中辅助纬度与大地纬度间的正反解变换公式,发现和纠正了传统正解公式高阶项中的一些错误;借助Hermite插值法得到了符号形式的反解表达式.将各辅助纬度展开式系数表示为简单的偏心率e的幂级数形式,使得系数的表示形式更为统一. 相似文献
43.
横卧于叶县境内干江河上游的燕山水库,是国家确定的治淮骨干工程,也是河南省重点工程。水库共占用叶县保安镇土地34000余亩,需搬迁村庄16个,迁移村民14000多人。自2005年3月正式开工建设以来,叶县国土资源局保安国土资源所充分发挥管理职能,为重点工程建设提供了优质高效的服务。 相似文献
44.
45.
广东省新丰江水库区于1962年3月19日发生6.1级地震。本文分析了1961年以来十四年间,特别是主震前后纵、横波速比Vp/Vs的变化过程。结果表明:波速比Vp/Vs在主震前出现了明显的负异常,总异常时间约为十一个月,于震前一个半月返回正常值,在主震震源附近的深水峡谷区异常幅度最大,异常时间和空间范围比一般构造地震的要小.后期几次强余震前也有异常变化。虚波速度在主震前存在某些异常特征。上述波速比的变化可以用扩容模式较好地解释。 波速比值是由两个台站的记录得到的。对虚波速度的计算采用了联合地震参数的方法。 相似文献
46.
许多实例表明,水库地震与地质构造有十分密切的关系。本文根据一些实际资料着重讨论了水库地震与活动性强烈的大地构造区、断裂带、断块间差异运动之间的关系 相似文献
47.
Norboo Tsering 《中国地球化学学报》2006,25(B08):69-69
Background: Radiographic signs of Pneumoconiosis found in farming Ladakhi despite absences of mines and industries were believed to be due to exposure to frequent dust storms and domestic fire pollutions. Seasonal Koilonychia (spoon nail) occurring predominantly in farming women in absences of iron deficiency anaemia was thought to arise from exposure to water made alkaline by weathering of hornblende minerals. The relation of these health conditions to environmental geohydrochemistry is postulated as the source of irrigation water in the affected population originates from glaciers in trans-Himalaya range of sedimentary geology and steep landscape favouring flushing of silica/silicate containing silts. Methods and results: Survey in two central Ladakh villages revealed radiographic evidence of silicosis in all middle aged women and half in middle aged men. In a large-scale study of 3105 subjects aged over 30 years from three villages; 101 (22.5%) of the 449 radiographed showed signs of pneumoconiosis (ILO 1980 criteria) including eggshell calcification of hilar gland and progressive massive fibrosis. Indoor dust analyzed using Philips 400T electron microscope with energy dispersive analysis system attached showed SiO2 levels upto 53.27% with particle size of 0.5 to 5.0 microns and the concentration during cooking period in the worst affected area was 7.495 mg/m^3. Microscopy and histopathology from the subject was characteristic of pneumoconiosis. Analysis of the inorganic dust in the lung showed 40.2% muscovite, 37.3% quartz with the extracted dust wt 147.9 mg/gm of dry tissue. Prevalence of chronic cough with chronic phlegm and percentage of villagers with FEV1/FVC ratio of less than 65% rose with age. Of 70 subjects studied 19 women and 2 men had Koilonychia with incidence being highest in summer. Absence of seasonal Koilonychia in villages fed by water derived from northern mountain range glaciers with mainly igneous geology supports our hypothesis. 相似文献
48.
In this research, chlorinated hydrocarbons (polychlorinated biphenyls and organochlorine pesticides) were measured by GC-ECD in sediments from the Hongfeng Reservoir area. The concentrations of total PCBs range from 3.2 to 31.6 ng/g, among which PCB28, PCB52 are the major congeners with the concentrations from 0.5 to 4.6 ng/g, and from 0.4 to 28.1 ng/g, respectively. The concentrations of these pollutants decrease from surface to bottom, while the concentrations at 1-4 cm are lower than at 5-8 cm, suggesting the decline of PCBs input. TOC concentrations of sediment are found in a significant positive correlation with those of PCBs, suggesting that PCBs are mainly adsorbed on organic matter and particles. HCHs and DDTs are the predominant organochlorine pesticides with the concentrations ranging from 1.6 to 8.9 ng/g (average 3.2 ng/g) and 0.9 to 25.7 ng/g (average 7.8 ng/g), respectively. β-HCH and γ-HCH (lindane) are the predominant HCH isomers from sediments, and p, p'-DDE and p, p'-DDT are the predominant DDT isomers. DDT/DDE+DDD and α-HCH/γ-HCH ratios range from 0.6 to 0.9 and 0.1 to 3.0, respectively, which indicates more use of lindane than technical mixtures of HCHs before, and also suggests changes in HCHs and DDTs in the environment. The high values of β-HCH and p, p'-DDE also show that atmospheric input is one of the important sources of the Hongfeng Reservoir, because β-HCH and p, p'-DDE are stable and have low Sw and Pv so that they can be easily transferred over a long range in atmosphere. 相似文献
49.
Teddy W. Sudinda Teddy 《中国地球化学学报》2006,25(B08):156-157
Flood and desiccation are perceived as two most critical and influential disasters which contradict between causes and consequences. Flood occurs when the water surface could no longer flow the whole water flow, thus, the water flooded. Contradicted to that, desiccation occurs when the water flow contains a low volume of water deposit, thus, the water requirement exceeds the available potential. That condition was caused by land utilization as the consequences due to the increased land requirement for housing or industrial needs. An attempt to overcome the flood, nowadays, is implemented mostly in a structural way, through building canals, implementing rivers normalization, building gateways or building flood control pump which are more directed toward the flood direction in order to increase the surface flow in an immediate maner to the sea. However, the effort to overcome the flood its self, could be more effective if followed by an effort to increase the soil ability to absorb natural recharge or artificial recharge or by refilling the water into the earth surface. Absorption reservoir used as one of technology alternatives (artificial recharge) could also be used to support the attempt to overcome flood and desiccation. Absorption reservoir is a dam which was designed according to the basic principles, such as the bottom surface of the reservoir that has a high permeability surface; the surface of the reservoir water is higher (higher aquifer) along with a high permeability, considering the availability of water source that has been absorbed and its quality; considering the aquifer category on the water absorption dam; 相似文献
50.
Yuchun WANG Jun ZHU Congqiang LIU 《中国地球化学学报》2006,25(B08):161-162
Damming is a common anthropogenic intervention along the course of rivers, which is defined as "artificial-lake effect", both in China and across the world. Today as many as 48000 dams and/or reservoirs are in operation in the Changjiang River (Yangtze River) drainage area, and more are being constructed. While damming is well known to affect riverbome nutrient loads, and thus the riverine ecosystems owing to removal of carbon fixation, and removal of particles in reservoir sediments, there is limited information on the detailed early diagenesis of sediments in reservoirs including the regeneration processes of nutrients deposited in sediments and exchange flux across the sediment-water interface, which is important for mass balance of riverbome nutrients. In the present study, two large-size reservoirs, Wujiangdu Reservoir (WJDR) and Dongfeng Reservoir (DFR), located on the main steam of the Wujiang River and with uniformity hydrography and discrepancy biogeochemical activity (e. g. primary production), were selected for a comparative study on the detailed processes of nutrient regeneration. Water, pore water and sediment were sampled from these two reservoirs and dissolved organic carbon (DOC), NH4^+, NO3^-, PO4^3-, dissolved silica (DSi) in the overlying water and pore water, and total organic matter in sediments were determined. The results of correlation analysis suggested that in these two reservoirs, processes of nutrient regeneration near the sediment-water interface were significantly different. As a result of rapid decomposition of algae-derived "labile" organic matter in upper sediments, nutrient regeneration processes and upward fluxes in WJDR are dramatically stronger than those of DFR. NH4^+ upward flux from sediment in WJDR was about 17 times higher than that in DFR. PO4^3- flux in WJDR is about 13 times above that in DFR. DOC flux in WJDR is larger that in DFR by 5 times, and DSi by 1 time. 相似文献