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一、前言 中纬度地区电离层Es的成因与影响因素是一复杂的问题。远东地区Es既多又强,其它电离层现象也有一些特色,本文在文献[9]的基础上,从分析原始频高图入手,对远东地区夜间f0Es剧增与地磁K指数的关系作了统计研究,发现两者之间关系甚为密切,即地磁K指数的突然变化伴随着夜间Es层临界频率f0Es的剧烈增加。 相似文献
2.
Introduction Human-induced environmental change in China has led to different consequences due to various causes. They conver certain regions and places where their impacts may threaten the long-term or even the short-term sustainability of human-environmental relationships. Designating such areas as "critical environmental situations," Russian Geographers have developed "red data maps" showing their locations[1]. Yet, there are no fully developed conceptualizations of environmental critical… 相似文献
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According to the data of optical observations of the Tuorla Observatory in Finland, using the power spectrum method, DCF (Discrete Correlation Function) method, and Jurkevich method, respectively, we analyzed the periodicity of the long-term light variation of the BL Lac object 1ES 1959+650, and obtained its light period to be P =1.4±0.3 yr. Assuming that the origin of the periodicity is concerned with the accretion disk, we obtained the region where the instability of this source occurs being R =9.65 Rg, here Rg represents the Schwarzschild radius. 相似文献
4.
Monika Cieszynska-Semenowicz Justyna Rogowska Wojciech Ratajczyk Joanna Ratajczyk Lidia Wolska 《国际泥沙研究》2018,33(2):191-197
Elemental sulfur(ES) is a component essential for proper development of animals, but it can be toxic for aquatic organisms. The objectives of the study reported here included determination of ES concentrations in sediment collected in the area of the Gulf of Gdansk(Baltic Sea) and search for the possible correlations with the ecotoxicity results. Sediment samples were collected from four locations: the Vistula River mouth, in the Port Basin, in the area of discharge of the treated wastewater from the Wastewater Treatment Plant(WWTP) and in the area of the sunken World War Ⅱ s/s 'Stuttgart' shipwreck. The levels of elemental sulfur were determined using a gas chromatograph coupled with a mass spectrometer(GC-MS). Toxicity of marine sediment samples was estimated for three biotest organisms-bioluminescent bacteria Vibrio fischeri, crustacean Heterocypris incongruens, and Synapis alba plant. The highest toxicity of sediments for all indicator organisms was observed in samples taken at the place of the shipwreck(2-100%). The same samples had a high sulfur content(16.7-143.2 μg/g dry weight(d.w.))therefore, it was decided to investigate whether the presence of ES in the sediment in the studied area can have an impact on the results of the ecotoxicity determination in real samples. However, the removal of sulfur from the samples resulted in no significant changes in the level of toxicity of the samples. In this research it could not be confirmed that the presence of elemental sulfur is the only factor responsible for the observed sediment toxicity. It seems that other compounds or their mixtures present in the sediment may have a significant influence on the results obtained. 相似文献
5.
Journal of Geographical Sciences - Global urbanization has led to drastic land use change, interfering the ecosystem services (ES) supply-demand balance, in turn threatening the well-being of... 相似文献
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Matthias Beilicke 《Astrophysics and Space Science》2007,309(1-4):139-145
The HESS experiment (High Energy Stereoscopic System), consisting of four imaging atmospheric Cherenkov telescopes (IACTs)
in Namibia, has observed many extragalactic objects in the search for very high energy (VHE) γ-ray emission. These objects include active galactic nuclei (AGN), notably Blazars, Seyferts, radio galaxies, starburst galaxies
and others. Beyond the established sources, γ-ray emission has been detected for the first time from several of these objects by HESS, and their energy spectra and variability
characteristics have been measured. Multi-wavelength campaigns, including X-ray satellites, radio telescopes, and optical
observations, have been carried out for AGNs, in particular for PKS 2155-304, H 2356-309 and 1ES 1101-232, for which the implications
concerning emission models are presented. Also results from the investigations of VHE flux variability from the giant radio
galaxy M 87 are shown.
For the HESS Collaboration. 相似文献
7.
The multiband nonthermal emissions in radio,X-ray,and very high-energy (VHE)γ-ray bands from two distant blazars,H 2356-309 and 1ES 1218+304,have been detected,and,especially from recent observations with the Suzaku,MAGIC and VERITAS telescopes,clearly reveal nonthermal power-law spectra. We study the broadband nonthermal spectra of the two sources by using a combination of a onezone homogeneous synchrotron self-Compton (SSC) model and an inhomogeneous conical jet model,where the new external background light (EBL) model is taken into account. The results show that (1) the nonthermal emissions of the two blazars,ranging from X-rays to VHE γ-rays,are from the homogeneous zone whereas the emissions in the radio bands can be explained as the radiation from the inhomogeneous conical jet; (2) a strict lower-limit EBL model can be used to explain their observed spectra well. 相似文献
8.
《武汉大学学报(信息科学版)》1995,(1)
为解决控制性规划管理中项目咨询、审批和管理问题，探讨了ＥＳ与ＧＩＳ结合的可能性，提出了ＺＯＭＡＮ的系统原型，介绍了ＺＯＭＡＮ的系统结构，并以温州市为例，说明了它的应用． 相似文献
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综合利用岩芯观察、岩石铸体薄片、流体包裹体、岩芯实测物性并结合埋藏史分析,对渤南洼陷北部陡坡带沙四上亚段砂砾岩储层的成岩演化和物性演化特征进行了研究.结果表明:储层经历了强烈压实、碳酸盐灰泥重结晶、多期胶结和溶解以及复杂交代等成岩演化过程.结合成岩环境演化特征,认为储层经历了多期酸碱交替的流体演化,在同一成岩环境演化背景下,由于近岸水下扇不同亚(微)相沉积特征差异性,控制了不同亚(微)相成岩演化特征的差异性,并决定了其物性演化的差异性.采用反演回剥的方法对地史时期近岸水下扇砂砾岩储层的物性进行了恢复,可知对储层物性演化起到重要影响的有压实作用、碳酸盐胶结、碳酸盐灰泥重结晶作用、酸性溶解及油气充注,并建立了近岸水下扇不同亚(微)相储层物性演化模式:扇根砾岩在埋藏过程中成岩作用以压实作用和灰泥杂基重结晶作用为主,溶解作用微弱,物性持续降低,在中深层灰泥杂基的重结晶作用使扇根砾岩物性快速降低,现今物性极差,主要发育干层.扇中辫状水道距泥岩层较远的储层,由于两期酸性溶解对储层的改造以及油气充注对胶结作用的抑制,中深层仍发育大量原生孔隙和次生孔隙,储层物性较好,可作为良好的油气储集层.扇中辫状水道距泥岩层较近的储层、扇中水道间和扇缘储层成岩作用以强烈胶结作用和交代作用为主要特征,现今物性差,主要发育干层. 相似文献
10.
惠民凹陷临邑断裂沙四、沙三段活动规律及对油气成藏的控制 总被引：3，自引：2，他引：1
研究了临邑断裂断层不同走向段的生长指数和断层落差,分析沙四、沙三段各沉积亚段地层沉积特征,研究发现断层的幕式活动控制了地层沉积和空间展布,沉降中心沿断裂带自西向东迁移;深入剖析断面发育特征与断层两盘岩性对置关系,探讨了临邑断裂带的油气运移轨迹及勘探潜力区带。 相似文献