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γ暴研究的重大突破:余辉的发现与观测研究 被引量:8
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作者 黄永锋 《天文学进展》 CSCD 北大核心 1998年第4期330-345,共16页
由于BeppoSAX卫星的独特贡献,最近观测到了若于Υ暴在X射线、光学甚至射电波段上的对应体,一度陷入困境的Υ暴研究再次取得了突破性的进展。目前已经观测到了Υ暴GRB970228持续六个月以上的光学余辉,发现它可能位于一个暗弱的宿主星... 由于BeppoSAX卫星的独特贡献,最近观测到了若于Υ暴在X射线、光学甚至射电波段上的对应体,一度陷入困境的Υ暴研究再次取得了突破性的进展。目前已经观测到了Υ暴GRB970228持续六个月以上的光学余辉,发现它可能位于一个暗弱的宿主星系中;GRB970508的光学余辉有较为复杂的表现,并测出其红移范围0.85<z<2.1。在该暴发生约五、六天之后,还观测到了射电耀发现象。观测上的重大突破比较有力地支持了Υ暴的宇宙学起源及火球模型。 展开更多
关键词 Γ射线 中子 γ星线天文学 Γ暴
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Study on Mutagenic Effect of Space Flight in Two-line Sterile Rice 被引量:1
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作者 杨震 彭选明 +2 位作者 彭伟正 庞爱军 庞伯良 《Agricultural Science & Technology》 CAS 2009年第4期105-107,174,共4页
Seeds of two-line sterile rice cultivars Zhu 1S and Lu 18S were carried into space by "Shijian 8" breeding recoverable satellite, then planted in ground. Mutagenic effects from space induction were compared with tho... Seeds of two-line sterile rice cultivars Zhu 1S and Lu 18S were carried into space by "Shijian 8" breeding recoverable satellite, then planted in ground. Mutagenic effects from space induction were compared with those from y-irradiation and complex processing of space induction and y-irradiation. The results showed that agronomic effect was stimulated in Mo progenies of the two-line sterile rice varieties treated by space flight, and their radiosensitivities to the irradiation of space flight performed non-sensitive. The order of mutation frequency was determined to be SP + γ 〉 γ 〉 SP in M2 generation. And a series of mutated elites(individuals) were screened. Physiological indices of mutants screened like the activity of protective enzymes were measured to explore the physiological and biochemical basis of biological effect in space environment to two-line sterile rice. The results of this study show that space mutation breeding is an effective novel mean for breeding. 展开更多
关键词 Space flight y-irradiation Complex process Two-line sterile variety Mutagenic effects
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仙女座和三角座
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作者 成怡然 《天文爱好者》 1995年第6期18-20,共3页
仙女座和三角座成怡然冬季的夜晚当我们仰望飞马座时,在其东北侧可以看到几颗亮星排成一列.它们属仙女座。飞马座四边形东北角的那颗亮星是仙女座α.仙女座所占天区面积722.3平方度,位于赤经:22时56分~2时36分,赤纬... 仙女座和三角座成怡然冬季的夜晚当我们仰望飞马座时,在其东北侧可以看到几颗亮星排成一列.它们属仙女座。飞马座四边形东北角的那颗亮星是仙女座α.仙女座所占天区面积722.3平方度,位于赤经:22时56分~2时36分,赤纬:21.4度~53.9度。每年11... 展开更多
关键词 仙女座 三角座 α γ星
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The gamma-ray spectral index changes for blazars 被引量:3
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作者 YANG JiangHe FAN JunHui +1 位作者 NIE JianJun YANG RuShu 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2012年第11期2179-2185,共7页
Based upon Fermi 1FGL and EGRET 3EG samples, a sample including 79 blazars (53 FSRQs, 26 BL Lacs) is presented. It is investigated that the correlations between the ratio of EGRET to Fermi blazars g-ray flux densiti... Based upon Fermi 1FGL and EGRET 3EG samples, a sample including 79 blazars (53 FSRQs, 26 BL Lacs) is presented. It is investigated that the correlations between the ratio of EGRET to Fermi blazars g-ray flux densities and the spectral index differ for EGRET to Fermi blazars for three subclasses of high-frequency peaked BL Lacertae objects-HBL, low-frequency peaked BL Lacertae objects-LBL, and flat spectrum radio quasars-FSRQs. There is a consistent relationship between the ratio of the two γ-ray flux densities and the spectral index difference for the three subclasses. It suggests that the spectrum changed with the source brightness in the gamma-ray band. Both the spectral index difference and the correlation slopes follow a continuous sequence from FSRQs to LBLs to HBLs, which is consistent with the noted blazar sequence. 展开更多
关键词 active galactic nuclei (AGN) BLAZARS gamma-ray emission spectral index
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