排序方式: 共有22条查询结果,搜索用时 187 毫秒
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富马酸单乙酯(FAME)的单脉冲1H MAS谱由-高分辨成分与-宽线谱成分组成.高分辨成分可由Hahn回波脉冲序列单独获得.文中通过变温1H MAS与CRAMPS实验对两组分的性质进行了系统的研究.发现当温度趋于样品的熔点时,其1H CRAMPS谱可观察到化学位移明显区别的两套谱,它们分别对应于1H MAS谱的高分辨与宽线组分.实验表明:高分辨成分来自FAME样品的-塑性相,而宽线组分来自通常的刚性相.文中所给出的实验事实充分说明1H MAS与CRAMPS技术是研究有机塑性固体的强有力的工具. 相似文献
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本文报道了一种测角单晶NMR探头。该探头采用单线圃双调谐电路,工作频率在90MHz-110 MHz连续可调,可进行交叉极化大功率去耦实验。文中提出了一种简单而有效的测角装置,可使单晶绕三个互相垂直轴转动实现单晶的NMR测量。作为典型的应用例子,本文利用该探头实现了单晶DGO(2NH2CH2COOH·H2C2O4)屏蔽张量的测量。 相似文献
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强场下煤的13C NMR谱 总被引:4,自引:1,他引:3
由强场静态13C煤谱可以获得与低场魔角旋转高分辨谱相同的fa,从而避免了样品的快速旋转的要求,同时得到了高灵敏度。 相似文献
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Experiments including ~(13)C spin-lattice relaxation, ~(13)C heteronuclear dipolar dephasing and~1H spin diffusion are performed on poly (2, 6-dimethyl-1, 4-phenylene oxide) (PPO). Theresults show that the rotation of the methyl groups in solid PPO is partially restricted, whichresults in a surprisingly efficient spin diffusion between the aromatic proton and methyl protoncharacterized by a diffusion time of 150μs. The results also show that the aromatic ring insolid PPO is rigid and twisted, which causes all aromatic carbons to be chemicallyunequivalent. 相似文献
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For those organic compounds which lack free radicals, a doping approach named melting-liquid-nitrogen-quench was developed in order to perform dynamic nuclear polarization(DNP)-nuclear magnetic resonance experiments. By using this method, the 1H, 13C, 15N DNP enhancements were observed with free-radical-doped dibenzofuran and benzamide. The enhancement mechanism and relation between the concentration of unpaired electrons and the maximum DNP enhancement are discussed. 相似文献
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描述了谱仪的同步控制装置.利用该装置,在MSL-400潜仪上实现了单晶化学位移张量的二维变角相关谱方法测量,获得了典型单晶的DGO (2NH3+CH2COO-·2·COOH)的13C化学位移张量。 相似文献