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101.
D. R. Xiong H. J. Zhang X. Zhang Y. G. Zheng T. F. Yi W. G. Liu Y. J. Cha B. J. Li 《Astrophysics and Space Science》2013,345(2):345-354
We study broad line and multi-wave luminosity relations for 80 flat-spectrum radio quasars (FSRQs) detected by Fermi LAT. Our results are as follows: for FSRQs, the correlations between logL γ and logL BLR, between logL X and logL BLR, between logL O and logL BLR, between logL R and logL BLR are significant; the correlation between logL IR and logL BLR (P=0.08) is not significant, but might be refereed as a “trend” of significant correlation. These results support a close link between jet formation and accretion disk, and the L γ -L BLR correlation suggests that the radiation mechanism of the γ-ray emission in FSRQs is likely to be inverse Compton scattering of seed photons from BLR or outflowing BLR. 相似文献
102.
Biostratigraphic analysis is an essential element for understanding global tectonics and the evolution of life on Earth. Quantitative analysis of sedimentary sequences provides the precise age constraints on timing of significant events in Earth’s history. This paper presents results from quantitative stratigraphic analysis of Upper Cretaceous Tethyan Himalayan sequences. This analysis resulted in a new composite stratigraphic section for the Cretaceous strata of Tibet (TIBETKCS). The eight Upper Cretaceous sections were analyzed in this study and 12 planktonic foraminifera zones were recognized based on available data. Quantitative measurements were made using a Graphic Correlation with Graphcor 3.0 software and correlated to the world standard Cretaceous Composite Section (MIDKCS). The sections were also examined using Constrained Optimization software by CONOP9. Level Penalty was applied as the rule to measure misfit among automatically correlated sections. The new TIBETKCS correlates well with planktonic foraminifera ages from previous work in southern Tibet. A fitting equation of y=?0.19x+305 with a correlation coefficient of 0.94 was obtained from this work. The ages of the first and last appearances of 64 planktonic foraminifera can be calculated with this equation with ± 0.3 Ma precision. This level of precision is approximately 10 times higher than age determinations with traditional methods. Two extinction events were resolved within this analysis at ~93.5 Ma and ~85.5 Ma corresponding to the Ocean Anoxic Events at Cenomanian–Turonian and Coniacian–Santonian boundaries respectively. 相似文献
103.
太湖水体氮、磷赋存量的逐月变化规律研究 总被引:5,自引:0,他引:5
基于中国科学院太湖湖泊生态系统研究站2005~2009年对太湖逐月叶绿素a、氮、磷各形态因子及水深的监测,结合太湖大浦水文站的逐日水位数据,估算出2005~2009年太湖的逐日水量,并运用泰森多边形法,估算出太湖水体总氮(TN)、总磷(TP)、溶解性总氮(TDN)、溶解性总磷(TDP)、硝态氮(NO3)、铵态氮(NH4)、亚硝态氮(NO2)、反应性活性磷(PO4)、颗粒态总氮(TPN)、颗粒态总磷(TPP)、浮游藻类叶绿素a(Chla)的逐月动态变化过程。结果表明:(1)太湖2005~2009年TN、TDN、NO2、NO3、NH4、TP、TDP、PO4、TPN、TPP、Chla的平均赋存量分别为1.36×104t、1.02×104t、0.02×104t、0.37×104t、0.25×104t、514.34 t、147.30 t、51.44 t、0.34×104t、367.04 t、7.92 t,不同月份、年际之间变化剧烈,变幅分别为106%、142%、657%、252%、233%、95%、196%、276%、236%、131%、276%;(2)2007年6月无锡贡湖水厂"饮用水危机"事件之后,截止到2009年12月,太湖水体各形态氮及总磷赋存量的下降趋势不明显,溶解性总磷、反应性活性磷的赋存量反而增高,反映出营养盐控制任务的艰巨性。本研究表明,对于年水量变幅巨大的大型湖泊,全湖水体营养盐赋存量在评估水体营养盐污染状况中是一个有价值的指标;对于太湖流域的污染控制效果,仅从浓度角度评价具有一定的缺陷,有必要从水体营养盐赋存量的变化规律上探讨其治理效果。 相似文献
104.
基于快速傅里叶方法的地震前兆振幅谱分析 总被引:1,自引:1,他引:0
利用FFT方法,对地电、地磁、形变及重力等前兆时间序列信号进行分析,结果显示,宝昌地震台及乌加河地震台地电两测向日均值时间序列存在3个主要谐波分量,其中周期近一年的分量物理意义明确.FFT方法在精确确定前兆时间序列中的干扰信息周期时具有较好的效果. 相似文献
105.
106.
???÷??????????????????????????????2000??????????????????????Bursa????????????в?????????54???????80??????????澫???????????????????????????????????80???????54????????????????顣 相似文献
107.
Jae-Hoon Cha Kwang-Bae Kim Ji-Na Song In-Soo Kim Jeong-Bin Seo Chul-Hwi Kwoun 《Ocean Science Journal》2013,48(4):319-328
This study was carried out to learn about differences in the sessile macrobenthic fauna communities between the artificial and natural habitats. There were some differences in terms of species composition and dominant species and community structure between two habitat types. The dominant species include Pollicipes mitella and Granuilittorina exigua in natural rocky intertidal zones; Monodonta labio confusa, Ligia exotica, Tetraclita japonica in the artificial rocky intertidal zones. Among all the species, L. exotica and T. japonica occurred only in the artificial rocky intertidal zone. The results of cluster analysis and nMDS analysis showed a distinct difference in community structure between artificial and natural rocky intertidal zones. The fauna in the natural rocky intertidal zones were similar to each other and the fauna in the artificial rocky intertidal zones were divided depending on the slope of the substratum. In the case of a sloping tetrapod, M. labio confusa and P. mitella were dominant, but at the vertical artificial seawall, Cellana nigrolineata, L. exotica T. japonica were dominant. The analysis of the species presented in natural and artificial rocky intertidal areas showed the exclusive presence of 10 species on natural rocks and 12 species on artificial rocks. The species in the natural rocky intertidal area included mobile gastropods and cnidarians (i.e. rock anemones), and the species in the artificial rocky intertidal area mostly included non-mobile attached animals. The artificial novel structure seems to contribute to increasing the heterogeneity of habitats for marine invertebrate species and an increase the species diversity in rocky coastal areas. 相似文献
108.
华北地区地震活动与地壳热结构关系研究 总被引:5,自引:0,他引:5
本文应用双差定位法对2009—2015年华北地区发生的地震进行了重新定位, 共得到6225次地震的精确定位结果. 结果显示, 重定位后的小震更加集中分布于断裂附近, 震源深度多为5—15 km. 利用基于三维分形磁化模型的中心点法获得了华北地区的居里点深度并计算了磁性层的平均地温梯度, 进而利用随温度变化的热导率一维稳态热传导方程获得了华北地区的地壳温度结构. 结果显示: ① 除张渤地震带中东部地区以外, 大多数地震均发生在地温梯度较小的地方; ② 1966年邢台MS7.2地震和1976年唐山MS7.8地震均发生在地温梯度较小的地方, 二者发生的温度约为200℃—300℃; ③ 大多数M≥2.0地震发生的温度为100℃—500℃, M≥4.0地震发生的温度多为200℃—400℃. 这些温度与实验室地壳岩石脆-塑性变形过渡区的温度测量值相当, 表明华北地区的地震多发生在地壳脆-塑性变形过渡区. 相似文献
109.
110.
承德庞家沟银多金属矿主要与中生代早白垩世大北沟期陆相火山活动有关,火山管道相附近构造有利部位和岩性物性差异界面为成矿有利部位。通过对研究区的物探异常特征进行研究,重点分析了该区域岩(矿)石电性特征、激电中梯异常特征和激电测深剖面异常特征,并结合该区域地质背景与资料,综合圈定成矿远景区。研究结果表明: 研究区岩(矿)体之间物性差异明显,电阻率与极化率异常可作为重要的地球物理找矿间接标志; 研究区内以近EW向构造为主,同时发育NS、NE和NW向断层。基于激电异常分析方法,在该区域共圈定6个靶区,IP1南段异常是寻找金矿的有利地段, IP6异常存在于银铅锌矿体中,为该区域的进一步找矿提供参考。 相似文献