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Yi-Zhong Fan Zi-Gao Dai Yong-Feng Huang Tan Lu Department of Astronomy Nanjing University Nanjing 《中国天文和天体物理学报》2002,2(5):449-453
The optical flash accompanying GRB 990123 is believed to be powered by the reverse shock of a thin shell. With the best-fit physical parameters for GRB 990123 and the assumption that the parameters in the optical flash are the same as in the afterglow, we show that: 1) the shell is thick rather than thin, and we have provided the light curve for the thick shell case which coincides with the observation; 2) the theoretical peak flux of the optical flash accounts for only 3×10~-4 of the observed. In order to remove this discrepancy, the physical parameters, the electron energy and magnetic ratios, εe and εB, should be 0.61 and 0.39, which are very different from their values for the late afterglow. 相似文献
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Lin Chuanyi 《中国地球化学学报》1990,9(2):132-136
Electronic structures of square planar coordinated transition metal ions in BaCuSi4O10 and CaCrSi4O10 are investigated using the ligand-field theory (LFT), angular overlap model (AOM) and iterative extended Hückel molecular
orbital theory (IET). The electronic energy levels of the natural mineral dioptase are also investigated, in which the Cu2+ ions occupy the sites of pseudo D4h symmetry. Both LFT and AOM predict that the crystal-field levels of transition metal ions in these compounds follow such
an order that E (2B1g <E(2B2g <E(2A1g )<E(2Eg ), and the frequencies of the crystal-field transitions obtained from point charge calculations are in good agreement with
those observed. However, the energy-level order cannot be determined unambiguously from the IET calculation because it depends
on the values of parameters chosen for the calculation. 相似文献
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近日,焦作市国土资源局山阳分局干部职工纷纷解囊,帮助生命垂危的新城国土所所长薛现桥共度难关。薛现桥同志从事国土资源工作10余年,工作积极主动,任劳任怨,连续多年被市局和分局评为先进工作者。 相似文献
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他一脸孩子气,却透着精明与干练,走起路来风风火火,办起业务老练利索。虽参加工作时间不长,却是局里上下公认的业务拔尖人才。 相似文献
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<正>(2010年8月1日,根据录音整理)听了今天的演讲比赛,我相信大家的感受是共同的:感动、激奋、震撼。此时此刻,我觉得演讲比赛的名次谁先谁后、演讲的技巧谁高谁低、演讲的肢体语言熟练与笨拙,都已经没有意义。因 相似文献
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在湖北省仙桃市彭场镇杨步垸与辉云口镇(今木兰村)交界处,有个湖名叫陈印湖。湖水清澈碧透,宛若明镜。湖岸百花吐艳,柳红垂金。每逢月圆之夜,湖中霞光万道,人们见了惊喜地高喊:“金印!金印在闪光!”有的人还怀着热切的希望在闪光处挖掘金印……神奇的景观展现着一幅动人的历史画卷,讲述着一个古老的传说。 相似文献
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9219人、14463人、51151人、69181……,一串串不断上升的触目惊心的遇难数字让我们一次又一次泪眼朦胧;87小时,160小时,200小时……,一个个不断刷新的生命奇迹令我们一次又一次欣喜万分。一车车昼夜不停运往灾区的救援物资,一笔笔不断飞往灾区的爱心捐款,让我们感受到了全中国人民万众一心、众志成城的力量。中国加油,四川加油的呐喊声响彻了神州大地。 相似文献
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提起宝石,人们脑海中常会浮现出欧洲贵妇手腕或颈项上那一件件熠熠闪光的亮眼饰品。是的,宝石是西方人非常喜爱的饰品,同我们东方人喜欢玉石一样。而在众多宝石中,最珍贵则要属红宝石了。红宝石的"Ruby"一词来源于拉丁语"Rubens",意为红色,是指颜色呈红色的刚玉。它与蓝宝石同属于刚玉族,但不是自然界所有红色的宝石都是红宝石,只有由Cr(铬)致色的红色的刚玉才能够叫作红宝石。红宝石摩氏硬度为9,是仅次于钻石的自然界中第二硬的天然矿物。同时它可以承受约2000摄氏度的高温而不熔化,这要比钻石不到1000摄氏度的熔点高出许多。红 相似文献