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Possible Relevance of the Allende Meteorite Conditions in Prebiotic Chemistry: An Insight into the Chondrules and Organic Compounds
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作者 Alejandro Heredia Barbero Héctor G. Vázquez López +8 位作者 Adriana L. Meléndez López Jorge A. Cruz Castañeda Daniel Luna Laviada Karina E. Cervantes de la Cruz Victor Meza Laguna Vladimir A. Basiuk Ivonne Rosales Chávez Alicia Negrón Mendoza Sergio Ramos Bernal 《Advances in Biological Chemistry》 2023年第3期82-99,共18页
The study of the mineral and organic content of the Allende meteorite is important for our understanding of the molecular evolution of the universe as well as the ancient Earth. Previous studies have characterized the... The study of the mineral and organic content of the Allende meteorite is important for our understanding of the molecular evolution of the universe as well as the ancient Earth. Previous studies have characterized the magnetic minerals present in ordinary and carbonaceous chondrites, providing information on the evolution of magnetic fields. The interaction of organic compounds with magnetic minerals is a possible source of chemical diversity, which is crucial for molecular evolution. Carbon compounds in meteorites are of great scientific interest for a variety of reasons, such as their relevance to the origins of chirality in living organisms. This study presents the characterization of organic and mineral compounds in the Allende meteorite. The structural and physicochemical characterization of the Allende meteorite was accomplished through light microscopy, powder X-ray diffraction with complementary Rietveld refinement, Raman and infrared spectroscopy, mass spectrometry, scanning electron microscopy, and atomic force microscopy using magnetic signal methods to determine the complex structure and the interaction of organic compounds with magnetic Ni-Fe minerals. The presence of Liesegang-like patterns of chondrules in fragments of the Allende structure may also be relevant to understanding how the meteorite was formed. Other observations include the presence of magnetic materials and nanorod-like solids with relatively similar sizes as well as the heterogeneous distribution of carbon in chondrules. Signals observed in the Raman and infrared spectra resemble organic compounds such as carbon nanotubes and peptide-like molecules that have been previously reported in other meteorites, making the Mexican Allende meteorite a feasible sample for the study of the early Earth and exoplanetary bodies. 展开更多
关键词 Allende meteorite Carbonaceous Chondrite Light Microscopy X-Ray Diffraction with the Rietveld Method Raman Spectroscopy Attenuated Total Reflectance Infrared Spectroscopy mass Spectrometry Scanning Electron Mi-croscopy Energy Dispersive X-Ray Spectroscopy Magnetic force Microscopy
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新版苏梅克公式更适合巨大撞击坑能量的计算
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作者 赵华东 李卫高 +1 位作者 党海山 田军东 《中阿科技论坛(中英文)》 2020年第11期205-208,共4页
对于陆地上的撞击坑,科学家往往需要根据撞击坑的直径来估算撞击能量。由于现在学术界还没有统一的公式来描述撞击这一复杂的物理过程,所以就出现了不同的学者估算的结果相差很远的情况,这令人很难判断哪一种结果更符合事实。对于一些... 对于陆地上的撞击坑,科学家往往需要根据撞击坑的直径来估算撞击能量。由于现在学术界还没有统一的公式来描述撞击这一复杂的物理过程,所以就出现了不同的学者估算的结果相差很远的情况,这令人很难判断哪一种结果更符合事实。对于一些地球历史上出现的、已经无法知道撞击角度的撞击坑,就迫切需要一种统一的公式得出一个比较中肯的计算结果。我们比较分析了前人科学家提出的多个公式,认为1990年尤金·苏梅克的公式最好,并对此进行简化和改良,得到了E=6.286 D3.4这样一个简洁的版本(D是以km表示的超过4 km的撞击坑直径,E是以百万吨TNT当量表示的能量)以适应非常巨大的陨星撞击能量的计算。这个公式得到的结果适中,和国际主流的计算结果相符合。文章的末尾,我们还给出了得到撞击能量之后,估算陨星的质量和体积的一般性方法。本文提出的改进版的公式和方法可供学者们和科学爱好者引用和参考。 展开更多
关键词 陨星 撞击坑 撞击能量 新版本的尤金苏梅克公式 估算陨星质量和体积的一般性方法
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