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α-异戊基-3,3-二甲基-2-降冰片烷甲醇中立体异构体的碳谱分析
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作者 徐瑞秋 康国君 《北京大学学报(自然科学版)》 CAS CSCD 北大核心 1990年第6期653-658,共6页
新化合物α-异戊基-3,3-二甲基-2-降冰片烷甲醇具有4对对映异构体,我们通过柱层析、^(13)C-NMR谱定量、DEPT技术、计算化学位移植等方法,确定了4对对映异构体的百分含量及各碳的化学位移。同时根据其百分含量,了解到α-异戊基-3,3-二甲... 新化合物α-异戊基-3,3-二甲基-2-降冰片烷甲醇具有4对对映异构体,我们通过柱层析、^(13)C-NMR谱定量、DEPT技术、计算化学位移植等方法,确定了4对对映异构体的百分含量及各碳的化学位移。同时根据其百分含量,了解到α-异戊基-3,3-二甲基-2-降冰片烷甲醇由相应的醛与Grignard试剂合成时,应符合Cram规则。 展开更多
关键词 降冰片烷甲醇 立体化学 碳谱分析
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熏蒸提取法对比测定不同土种中的微生物碳含量
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作者 范雪滢 赖伟 +3 位作者 徐志锐 梁诗捷 邓豪健 梅承芳 《中国无机分析化学》 CAS 北大核心 2023年第12期1389-1395,共7页
土种是土壤发生分类中的最基础分类单元,基于土种的微生物量调查是土壤生物调查中的重要工作,其中微生物量以微生物碳含量表征。采用氯仿熏蒸提取法-碳光谱分析法和重铬酸钾氧化法对比测定土壤中的微生物碳含量,对于提取液中的有机碳含... 土种是土壤发生分类中的最基础分类单元,基于土种的微生物量调查是土壤生物调查中的重要工作,其中微生物量以微生物碳含量表征。采用氯仿熏蒸提取法-碳光谱分析法和重铬酸钾氧化法对比测定土壤中的微生物碳含量,对于提取液中的有机碳含量,碳光谱分析法的检出限为0.11 mg/L,重铬酸钾氧化法的检出限为1.55 mg/L。在精密度实验中,对于熏蒸后的土样,碳光谱分析法的RSD为8.8%~9.9%,重铬酸钾氧化法的RSD为7.0%~17.6%。对于未熏蒸处理的土样,两种方法的RSD分别为5.3%~9.3%和9.3%~12.0%。微生物碳测试结果与土壤的水分含量相关性显著(p<0.05)。对比两种方法的测定结果,发现熏蒸土样的相对偏差为0.1%~49.4%,未熏蒸土样的相对偏差为0~60.9%,低浓度样品的偏差较大。对于不同土种中微生物碳含量的测定,碳光谱分析法测得结果为146~414μg/g dry soil,重铬酸钾氧化法为131~407μg/g dry soil,两种方法测定结果间无显著差异。结果表明,低浓度样品测定时采用重铬酸钾氧化法造成的误差较大,宜采用碳光谱分析法,两种方法均能有效测定不同土种中的微生物碳含量。 展开更多
关键词 熏蒸提取法 微生物 土种 谱分析 重铬酸钾氧化法
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碳碳相关谱测定Oplopanone的结构 被引量:14
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作者 彭国平 楼凤昌 《天然产物研究与开发》 CAS CSCD 2001年第6期9-11,共3页
从四川产泽泻 (AlismaorientalisJuzep .)中分离出一个倍半萜成分 ,经碳碳相关等核磁谱测定为Oplopanone。该成分为首次从泽泻科中分得 ,利用碳碳相关信息对该成分的碳谱进行了全归属 ,并讨论了该化合物的生物合成途径。
关键词 泽泻 Oplopanone 二维相关谱分析技术 中药材
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CS_2 extraction and FTIR & GC/MS analysis of a Chinese brown coal 被引量:4
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作者 TIAN Damin LIU Xiangyun DING Mingjie 《Mining Science and Technology》 EI CAS 2010年第4期562-565,共4页
The abundance of low-rank coals in China, such as bituminous and brown coals, makes studies of their composition and structure of great significance to both coal chemistry research and for efficient utilization of the... The abundance of low-rank coals in China, such as bituminous and brown coals, makes studies of their composition and structure of great significance to both coal chemistry research and for efficient utilization of the coal. We describe how a Chinese brown coal was ultrasonically extracted with carbon disulfide (CS2) and the raw and extracted coals were characterized by Fourier Transform Infrared Spectroscopy (FTIR). The corresponding extract was analyzed with a coupled gas chromatograph mass spectrometer (GC/MS). The FTIR analysis shows a great abundance of amidocyanogen, carbonyl, aromatic and hetero aromatic rings and single carbon-beteroatom bonds. This suggests the possible occurrence of compounds like alcohols, phenols, amines, esters, carboxylic acids, ethers, aromatics or heteroaromatics. The GC/MS analysis of the CS2 extract detected 62 compounds, among which the non-polar ones were of lower abundance while the polar ones were in higher abundance and were structurally diverse. This demonstrates the compositional and structural complexity of Shengli coal. 展开更多
关键词 low-rank coal solvent extraction FTIR GC-MS analysis
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Polycyclic aromatic hydrocarbon formation under simulated coal seam pyrolysis conditions 被引量:5
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作者 Liu Shuqin Wang Yuanyuan +2 位作者 Wang Caihong Bao Pengcheng Dang Jinli 《Mining Science and Technology》 EI CAS 2011年第4期605-610,共6页
Coal seam pyrolysis occurs during coal seam fires and during underground coal gasification. This is an important source of polycyclic aromatic hydrocarbon (PAH) emission in China. Pyrolysis in a coal seam was simula... Coal seam pyrolysis occurs during coal seam fires and during underground coal gasification. This is an important source of polycyclic aromatic hydrocarbon (PAH) emission in China. Pyrolysis in a coal seam was simulated in a tubular furnace. The 16 US Environmental Protection Agency priority controlled PAHs were analyzed by HPLC. The effects of temperature, heating rate, pyrolysis atmosphere, and coal size were investigated. The results indicate that the 3-ring PAHs AcP and AcPy are the main species in the pyrolysis gas. The 2-ring NaP and the 4-ring Pyr are also of concern. Increasing temperature caused the total PAH yield to go through a minimum. The lowest value was obtained at the temperature of 600℃. Higher heating rates promote PAH formation, especially formation of the lower molecular weight PAHs. The typical heating rate in a coal seam, 5 ℃/min, results in intermediate yields of PAHs. The total PAHs yield in an atmosphere of N2 is about 1.81 times that seen without added N2, which indicates that an air flow through the coal seam accelerates the formation of PAHs. An increase in coal particle size reduces the total PAHs emission but promotes the formation of 5- and f-ring PAHs. 展开更多
关键词 PAHs Coal field fires Underground coal gasification Lignite
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Lipid Oxidation and Fatty Acid Composition in Salt-Dried Yellow Croaker(Pseudosciaena polyactis) During Processing 被引量:5
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作者 CAI Qiuxing WU Yanyan +3 位作者 LI Laihao WANG Yueqi YANG Xianqing ZHAO Yongqiang 《Journal of Ocean University of China》 SCIE CAS CSCD 2017年第5期855-862,共8页
Lipid oxidation in salt-dried yellow croaker(Pseudosciaena polyactis) was evaluated during processing with commonly used analytical indices, such as the peroxide value(POV), the thiobarbituric acid reactive substances... Lipid oxidation in salt-dried yellow croaker(Pseudosciaena polyactis) was evaluated during processing with commonly used analytical indices, such as the peroxide value(POV), the thiobarbituric acid reactive substances(TBARS) value, and oxidative-relative lipoxygenase(LOX) activity. Additionally, fatty acids were analyzed using gas chromatography-mass spectrometry. Both POV and TBARS increased significantly(P < 0.05) at the rinsing stage. POV reached its peak value of 3.63 meq O_2 per kg sample at the drying stage, whereas TBARS constantly increased from 0.05 to 0.20 mg MDA per kg sample. Processing of salt-dried yellow croaker had an extremely significant(P < 0.01) effect on LOX activity. Twenty-six fatty acids were identified. Combined eicosapentaenoic acid(EPA; C20:5n3) and docosahexaenoic acid(DHA; C22:6n3) content varied between(19.20 ±0.37) mg g^(-1) and(23.45 ± 1.05) mg g^(-1). The polyunsaturated fatty acid/saturated fatty acid(PUFA/SFA) ratio in yellow croaker was 0.73–1.10, and the n-6/n-3 PUFA ratio was approximately 0.13–0.20. The contents of most fatty acids varied significantly(P <0.05) during the different processing stages, and these differences were caused by lipid oxidation. C18:0, C16:1n7, C19:0, and C22:6n3 showed clear changes in principle component one of a principle components analysis. These fatty acids are potential markers for evaluating lipid oxidation in fish muscle because there was a significant correlation between these markers and TBARS and LOX activity(P < 0.05) with Pearson's coefficients > 0.931. 展开更多
关键词 Pseudosciaena yellow PUFA Lipid constantly varied saturated dried lipoxygenase extremely
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Fatty acid profiles of muscle from large yellow croaker (Pseudosciaena crocea R.) of different age 被引量:2
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作者 Hong-gang TANG Li-hong CHEN +1 位作者 Chao-geng XIAO Tian-xing WU 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2009年第2期154-158,共5页
We investigated the fatty acid profiles of muscle from large yellow croaker (Pseudosciaena crocea R.) of different age. One- and two-year-old fish were cultured in floating net cages and sampled randomly for analysi... We investigated the fatty acid profiles of muscle from large yellow croaker (Pseudosciaena crocea R.) of different age. One- and two-year-old fish were cultured in floating net cages and sampled randomly for analysis. Moisture, protein, lipid and ash contents were determined by methods of Association of Analytical Chemist (AOAC) International. Fatty acid profile was deter- mined by gas chromatography. Crude protein, fat, moisture and ash contents showed no significant differences between the two age groups. The contents of total polyunsaturated fatty acids and docosahexaenoic acid (DHA) were significantly higher and eicosapentaenoic acid (EPA) content was significantly lower in the two-year-old large yellow croaker than in the one-year-old (/'〈0.05). No significant differences were observed in the contents of total saturated fatty acids and monounsaturated fatty acids, or the ratio ofn-3/n-6 fatty acids among the large yellow croakers of the two age groups. We conclude that large yellow croakers are good food sources of EPA and DHA. 展开更多
关键词 Fatty acid Large yellow croaker Age
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Mapping of Total Carbon and Clay Contents in Glacial Till Soil Using On-the-Go Near-Infrared Reflectance Spectroscopy and Partial Least Squares Regression 被引量:2
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作者 SHEN Zhang-Quan SHAN Ying-Jie +1 位作者 PENG Li JIANG Yu-Gen 《Pedosphere》 SCIE CAS CSCD 2013年第3期305-311,共7页
Characterizing spatial variability of soil attributes, using traditional soil sampling and laboratory analysis, is cost prohibitive. The potential benefit of managing soils on a site-specific basis is well established... Characterizing spatial variability of soil attributes, using traditional soil sampling and laboratory analysis, is cost prohibitive. The potential benefit of managing soils on a site-specific basis is well established. High variations in glacial till soil render detailed soil mapping difficult with limited number of soil samples. To overcome this problem, this paper demonstrates the feasibility of soil carbon and clay mapping using the newly developed on-the-go near-infrared reflectance spectroscopy (NIRS). Compared with the geostatistics method, the partial least squares regression (PLSR), with NIRS measurements, could yield a more detailed map for both soil carbon and clay. Further, by using independent validation dataset, the accuracy of predicting could be improved significantly for soil clay content and only slightly for soil carbon content. Owing to the complexity of field conditions, more work on data processing and calibration modeling might be necessary for using on-the-go NIRS measurements. 展开更多
关键词 independent validation on-the-go measurement soil carbon mapping soil clay mapping soil sensors
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