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本研究联合使用川滇地区36个台站(云南区域数字台网中22个台站,四川区域数字地震台网中14个台站)记录的644个帆3.5~6.0地震共7468条波形数据,开展川滇地区Lg波Q值层析成像研究.研究中以2.8~3.6km/s的传播速度窗选取Lg波波段,采用平移窗方法计算Lg波垂直向观测位移谱.我们首先利用Lg波观测谱反演得到了研究区的平均QLg(f),通过棋盘测试方法确定将研究区划分为0.5°×0.5°的网格,用平均值QLg-1作为每个网格的初始值,分别反演了0.5Hz,1Hz,2Hz,5Hz等多个频率的QLg(f)分布. 相似文献
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Phenylalkanes with carbon numbers between 16 and 19, characterized by the main carbon-18, have been identified in the modern sediments collected from gas hydrate area from the Gulf of Mexico. The structure of phenylalkanes with four isomers for every carbon number was determined by means of their mass spectra and previous studies. The distribution of the series characterized by a low molecular mass was similar to the distribution of n-alkane, alkylcyclohexanes and alkylbenzenes in each sample. There were differences in the distribution of the phenylalkane series between the S - 1, S - 4, S - 7, S - 9 samples and the S - 8, S - 10 and S - 11 samples. The phenylalkanes might be derived from Archaea associated with anaerobic oxidation of methane (AOM) processes in S - 1, S -4, S -7 and S -9 samples according to their distribution resembled with the distribution of the extract from a type of Archaea. The distribution of alkylcyclohexanes and alkylbenzenes in S - 1, S - 4, S - 7 and S - 9 sample was found to be similar to each other. The odd-over-even predominance of alkylcyclohexanes was seen as the input of some bac- terial. 相似文献
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Water quality assessment by pollution-index method in the coastal waters of Hebei Province in western Bohai Sea, China 总被引:8,自引:0,他引:8
Sources of pollution discharges and water quality samples at 27 stations in 2006 in the coastal waters of Hebei Province, western Bohai Sea, have been analyzed in this study. Pollutant loads from industrial sewages have shown stronger impact on the water environment than those from the general sewages. Analysis indicates that pollution of COD is mainly resulted from land-based point pollutant sources. For phosphate concentration, non-point source pollution from coastal ocean (fishing and harbor areas) plays an important role. To assess the water quality conditions, Organic Pollution Index and Eutrophication Index have been used to quantify the level of water pollution and eutrophication conditions. Results show that pollution was much heavier in the dry season than flood season in 2006. Based on COD and phosphate concentrations, results show that waters near Shahe River, Douhe River, Yanghe River, and Luanhe River were heavily polluted. Water quality in the Qinhuangdao area was better than those in the Tangshan and Cangzhou areas. 相似文献
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1976年和林格尔6.3级地震前后震兆特征分析 总被引:2,自引:0,他引:2
从时空变化特征、震源参数、地震波谱特征,b值,Vp/Vs,Q值,持续时间衰减比,Ap/As等方面对1976年4月6日和林格尔6.3级地震进行了较为全面的分析,着重分析了地震前后2年左右出现的运动学和动力学变化特征,以提取和林格尔6.3级地震的短临信息,分析后认为此次地震出现的震兆特征与包头6.4级地震,张北6.级地震某些方面有相似处,对探讨分析未来阴山、燕山地震带浅源中强震的孕育过程及提取临震信息,具有参考意义。 相似文献
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在对单项观测资料进行概率化的基础上,以唐山地区和乌鲁木齐地区为研究区,计算分析了多种前兆观测资料的合成缺信量,结果表明在强震和中强震发生前,合成缺信量的低值异常过程是比较明显的。进行这项研究对于综合识别多种前兆变化图象及在实际预报中的应用均有一定的意义。 相似文献