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文摘
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甲烷水合物(CH_4·nH_2O)是主要由甲烷和水分子构成的冰状笼型化合物,在自然界储量巨大.固体核磁共振(NMR)波谱和激光拉曼光谱是在分子水平分析甲烷水合物的重要手段.该文利用低温固体核磁共振碳谱(~(13)C NMR)对合成的甲烷水合物结构进行了研究,分别使用~(13)C交叉极化(13C CP)和高功率质子去偶(~1H HPDEC)2种脉冲程序采集甲烷水合物的~(13)C NMR谱图,结合实验结果分析及理论推导可知,使用~1H HPDEC方法得到的~(13)C NMR谱图信号更强,更利于定量分析;甲烷气体与冰粉合成的甲烷水合物为I型,其大笼和小笼占有率分别为0.988和0.824,水合数为6.07;甲烷气体与SH2站位沉积物和冰粉合成的甲烷水合物也为I型,其大笼和小笼占有率分别为0.987和0.887,水合数为5.98;SH2站位沉积物使合成的甲烷水合物的小笼占有率提高、水合数降低、水合物饱和度提高.激光拉曼光谱结果证实了上述结果的准确性.该文为甲烷水合物测试提供了重要的方法参考. |
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其他语种文摘
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Methane hydrates (CH_4·nH_2O) mainly composed of methane and water are ice-like crystalline clathrate compounds. They form a large natural gas reservoir due to their abundance. Solid-state NMR and laser Raman spectroscopy are two techniques which can be used for microscopic analysis for methane hydrates. In this paper, a low temperature solid-state ~(13)C NMR technology was used to study the structures of synthesized methane hydrates. It was shown that 1H high power decoupling (~1H HPDEC) had a better performance than ~(13)C cross polarization (13C CP) for quantitative analysis for methane hydrates. The NMR results indicated that the methane hydrates synthesized by mixing methane gas with ice powder had a type-I structure, with large and small cage occupancies of 0.988 and 0.824, respectively, and a hydrate number of 6.07. Methane hydrates synthesized by mixing the methane gas with the continental slope of the South China Sea site SH2 sediments and ice powder also had a type-I structure, with large and small cage occupancies of 0.987 and 0.887, respectively, and a hydrate number of 5.98. The result showed that addition of site SH2 sediments could reduce hydrate number of methane hydrates, and make small cage occupancy and hydrate saturation higher, which were verified by laser Raman spectroscopy. |
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来源
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波谱学杂志
,2017,34(2):148-155 【扩展库】
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DOI
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10.11938/cjmr20170203
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关键词
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固体~(13)C NMR
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激光拉曼光谱
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甲烷水合物
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地址
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1.
中国科学院广州地球化学研究所, 中国科学院天然气水合物重点实验室, 广东, 广州, 510640
2.
青岛海洋地质研究所, 国土资源部天然气水合物重点实验室;;青岛海洋科学与技术国家实验室, 山东, 青岛, 266071
3.
中国科学院广州能源研究所, 中国科学院天然气水合物重点实验室, 广东, 广州, 510650
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语种
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中文 |
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文献类型
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研究性论文 |
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ISSN
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1000-4556 |
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学科
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物理学 |
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基金
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中国科学院广州能源研究所所长创新基金培育专项
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中国石油-中科院科技合作项目
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国家自然科学基金资助项目
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文献收藏号
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CSCD:5999314
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