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本文根据灾害威胁的范围不同,提出了自然灾害与技术灾害在不同的社会时期和不同性质的国家的分布与造成的影响不同的观点,进而从灾害研究的历史中分析自然灾害与技术灾害的内在联系以及人们对灾害研究的观念与方法的历史变革。在上述基础上,重点阐述了灾害评估的基本概念、灾害评估的内容和程序以及灾害管理的过程与方法。 相似文献
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Korzennik SG Brown TM Fischer DA Nisenson P Noyes RW 《The Astrophysical journal》2000,534(2):L147-L150
We present deep Hubble Space Telescope (HST) imaging, as well as ground-based imaging and spectroscopy, of the optical afterglow associated with the long-duration gamma-ray burst GRB 990712 and its host galaxy. The data were obtained 48-123 days after the burst occurred. The magnitudes of the host (R=21.9, V=22.5) and optical afterglow (R=25.4, V=25.8, 47.7 days after the burst) favor a scenario in which the optical light follows a pure power-law decay with an index of alpha approximately -1.0. We find no evidence for a contribution from a supernova like SN 1998bw. This suggests that either there are multiple classes of long-duration gamma-ray bursts or that the peak luminosity of the supernova was more than 1.5 mag fainter than SN 1998bw. The HST images and EFOSC2 spectra indicate that the gamma-ray burst was located in a bright, extended feature (possibly a star-forming region) 1.4 kpc from the nucleus of a 0.2L*B galaxy at z=0.434, possibly a Seyfert 2 galaxy. The late-time afterglow and host galaxy of GRB 990712 bear some resemblance to those of GRB 970508. 相似文献
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Krahn MM Hanson MB Baird RW Boyer RH Burrows DG Emmons CK Ford JK Jones LL Noren DP Ross PS Schorr GS Collier TK 《Marine pollution bulletin》2007,54(12):1903-1911
“Southern Resident” killer whales include three “pods” (J, K and L) that reside primarily in Puget Sound/Georgia Basin during the spring, summer and fall. This population was listed as “endangered” in the US and Canada following a 20% decline between 1996 and 2001. The current study, using blubber/epidermis biopsy samples, contributes contemporary information about potential factors (i.e., levels of pollutants or changes in diet) that could adversely affect Southern Residents. Carbon and nitrogen stable isotopes indicated J- and L-pod consumed prey from similar trophic levels in 2004/2006 and also showed no evidence for a large shift in the trophic level of prey consumed by L-pod between 1996 and 2004/2006. ∑PCBs decreased for Southern Residents biopsied in 2004/2006 compared to 1993–1995. Surprisingly, however, a three-year-old male whale (J39) had the highest concentrations of ∑PBDEs, ∑HCHs and HCB. POP ratio differences between J- and L-pod suggested that they occupy different ranges in winter. 相似文献
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中国典型煤的激光显微荧光特征及R—I—VRo相关模式图的建立 总被引:1,自引:0,他引:1
利用激光显微荧光探针、MPV-Ⅲ显微光度计等方法系统地研究了我国典型煤的激光显微荧光特征,并运用二项参数(I400、R)与澳大利亚同期煤进行了对比,结果发现我国煤的I400普遍比澳大利亚同期煤高,据此,建立了我国煤的R-I-VRo相关模式图,该图对于正常评价我国烃源岩成熟度具有重要意义。 相似文献