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近两年国内气相色谱的进展 总被引:1,自引:0,他引:1
对近两年国内学者对气相色谱(GC)的研究和应用进行了综述.GC已经是一门十分成熟和广泛应用的分析技术,近两年国内学者的研究发展近似于国外的GC研究和发展,基础性GC研究不多,大多为GC在各个领域的应用研究.应用研究包括在食品、中药、水、气、石油、石化、工业品、农残和烟草分析中的应用. 相似文献
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综述了近年来环状芳香低聚物的合成及应用研究发展状况,对其合成方法和应用情况进行了综述和分析,并对今后的研究发展进行了预测。 相似文献
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通过文献研究的方法,探讨了现实增强技术在化学教学应用中的研究现状、教学应用价值和未来的研究方向。研究表明,现实增强技术在化学教学中具有较广阔的应用前景,合理使用将会带来化学教学方式和教学模式新的变革。化学现实增强教学研究需要实现由技术应用到化学教学整合的转变,关注学习过程研究,寻求硬件、技术和教师专业能力限制的突破,并以理性的眼光来审视其在化学实验教学、教育现实中的应用路径。 相似文献
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国内气相色谱近年的进展 总被引:17,自引:0,他引:17
本文对近三年国内学者在气相色谱方面的研究和应用作了综述 ,国内学者的研究基本和国际上气相色谱方面的研究类似 ,在全二维气相色谱、快速气相色谱 ,微型气相色谱仪、新型气相色谱固定相和色谱柱的溶胶 凝胶涂渍技术领域的研究方面作出了贡献。有关气相色谱的应用研究中 ,介绍了大量在药物分析、食品分析、环境分析、石油和石化分析和化工产品及高聚物分析等领域中应用的题目和摘要 相似文献
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阐述了电势-pH图的意义、研究现状及应用,详述了电势-pH图的计算机自动成图,主要包括:图形算法、算法的实现和图形表示;概述了电势-pH图在湿法冶金和防腐研究中的应用,并探讨了电势-pH图今后研究的重点和方向。 相似文献
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本文研究了改进石墨炉原子吸收光谱分析的几个途径,并联合应用这些手段较为深入地研究了钒和锗的方法,自制了光电测湿装置,应用测量慢速升温吸光度-时间曲线的办法和分子吸收光谱法,x-射线衍射法等对应用涂锆管测定锗的原子化机理进行了研究,提出了新的观点。制定了环境样品中痕量 相似文献
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Ye Feng Wang Yuan Zhou Jia Rui Wang Lei Liu Qing Xiang Guo Department of Chemistry University of Science Technology of China Hefei China 《中国化学快报》2007,18(5):499-501
N,N0-Diarylhydrazines have been prepared via the reaction of N-Boc-aryl hydrazines with boronic acids mediated by copper acetate. This mild reaction condition tolerates the presence of a variety of functional groups. 相似文献
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《Journal of Coordination Chemistry》2012,65(5):863-874
New heteronuclear Ln(III)–Bi(III) complexes (Ln?=?Nd, Eu, Tb, Yb, Lu) with ethylenediamine-N,N,N′,N′-tetraacetic (H4edta), trans-1,2-cyclohexane-diamine-N,N,N′,N′-tetraacetic (H4cdta), diethylenetriamine-N,N,N′,N″,N″-pentaacetic (H5dtpa), and triethylenetetraamine-N,N,N′,N″,N″′,N″′-hexaacetic (H6ttha) acids have been synthesized with a different synthetic approach. Bi(III) is a sensitizer of the 4f-luminescence in visible and near IR region. Emission spectra of Eu(III)–Bi(III) complexes were studied and the asymmetry of Eu(III) coordination environment was estimated, in good agreement with molecular models. The complexes synthesized by self-assembly are characterized by higher values of the 4f-luminescence quantum yield than other Ln(III)–Bi(III) complexes. 相似文献
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Dr. Lajos Kovács 《Chemical record (New York, N.Y.)》2023,23(1):e202200203
Nucleic acids play a pivotal role in life processes. The endeavours to shed light on the essential properties of these intriguing building blocks led us to the synthesis of different analogues and the investigation of their properties. First various peptide nucleic acid monomers and oligomers have been synthesized, using an Fmoc/acyl protecting group strategy, and their properties studied. The serendipitous discovery of a side reaction of coupling agents led us to the elaboration of a peptide sequencing method. The capricious behaviour of guanine derivatives spurred the determination of their substitution pattern using 13C, 15N NMR, and mass spectrometric methods. The properties of guanines initiated the logical transition to the study of supramolecular systems composed of purine analogues. Thus, xanthine and uracil derivatives have been obtained and their supramolecular self-assembly properties scrutinized in gas, solid, and liquid states and at solid-liquid interfaces. 相似文献
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IntroductionAbouttenyearsago ,PNA ,astructuralmimicofDNAinwhichthesugar phosphatebackboneisreplacedbyN (2 aminoethyl)glycine (aeg)linkageemergedasapotentialanti sensetherapeuticagent.1PNAhassomeadvantages:(1)itisstabletocellularnucleasesandproteases,(2 )ithybridizeswithcomplementaryDNAorRNA (cDNA/RNA)sequenceswithhighaffinity ,(3)ithaslownon specificinteractionwithcellularcontentsand (4 )itiseasilysynthesizedbyadoptionofsolidphasepeptidesynthesischemistry .However,thema jorlimitationo… 相似文献
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Hydrogenations at Room Temperature and Atmospheric Pressure with Mesoionic Carbene‐Stabilized Borenium Catalysts 下载免费PDF全文
Dr. Patrick Eisenberger Brian P. Bestvater Eric C. Keske Dr. Cathleen M. Crudden 《Angewandte Chemie (International ed. in English)》2015,54(8):2467-2471
1,2,3‐Triazolylidene‐based mesoionic carbene boranes have been synthesized in a convenient one‐pot protocol from the corresponding 1,2,3‐triazolium salts, base, and borane. Borenium ions are obtained by hydride abstraction and serve as catalysts in mild hydrogenation reactions of imines and unsaturated N‐heterocycles at ambient pressure and temperature. 相似文献
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The 14N nuclear quadrupole resonance (NQR) quadrupole coupling tensors of picolinic, nicotinic, isonicotinic and dinicotinic acids have been determined. Two different 14N quadrupole coupling constants 1007 kHz and 4159 kHz have been observed for picolinic acid demonstrating the presence of both protonated and non-protonated nitrogen atoms in this system in the solid. Only one set of non-protonated 14N NQR lines has been observed in other pyridinecarboxylic acids demonstrating the absence of the protonated zwitter ion forms observed in picolinic acid. The non-protonated 14N quadrupole coupling constant is the highest for the non-protonated nitrogen in picolinic acid and decreases to 3774 kHz in nicotinic acid and 3570 kHz in isonicotinic acid. It is the lowest in dinicotinic acid where the corresponding 14N quadrupole coupling constant is 2794 kHz. The observed anomalous decrease in the 14N quadrupole coupling constant of dinicotinic acid with decreasing temperature is tentatively explained as reflecting the increase in the residence time of the N–H?O bonded proton in the potential well close to the nitrogen. 相似文献
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A. B. Rozhenko W. W. Schoeller V. N. Kozel V. E. Pashinnik Yu. G. Shermolovich 《Magnetic resonance in chemistry : MRC》2009,47(9):791-800
The parent (H2N? S? F) and N,N‐dialkyl‐substituted fluorides of amidosulfoxylic acid (R2N? S? F, R?Me or R2N?Morph) as well as the related compounds X? S? F (X?CH3, OH, F, SiH3, PH2, SH, Cl) have been investigated with quantum chemical calculations at the ab initio (MP2) level of approximation. The geometries, electronic structures, molecular orbital (MO) energies and NMR chemical shift values have been calculated to evaluate the role and extent of the polarization and delocalization effects in forming of the high‐field fluorine NMR resonances within the series of interest. The δF magnitudes for all investigated fluorides of amidosulfoxylic acid as well as the δN value calculated for Me2N? S? F are in the good agreement with the 19F and 14N NMR chemical shift values measured experimentally. For the parent compounds, H2N? S? F and H2N? SO2? F, the orientation of principal axes of the magnetic shielding tensors and the corresponding principal σii values along these axes have been qualitatively interpreted basing on the analysis of the MO interactions in the presence of the rotating magnetic field. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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Jarno Riefer Ludwig Zapf Dr. Raphael Wirthensohn Dr. Philipp T. Hennig Dr. Tatjana Ribbeck Dr. Jan A. P. Sprenger Dr. Nikolai V. Ignat'ev Prof. Dr. Maik Finze 《European journal of organic chemistry》2023,26(17):e202300031
Cyanoborane adducts of the Lewis acids B(CN)3, BF(CN)2, and BH(CN)2 with pyridine and 4-cyanopyridine have been obtained in high yields. The syntheses were accomplished by oxidation of the readily available potassium salts of the cyano(hydrido)borate anions [BH(CN)3]− ( MHB ), [BFH(CN)2]− ( FHB ), and [BH2(CN)2]− ( DHB ) with bromine in the presence of the respective pyridine derivative C5H5N or 4-CN-C5H4N as starting material. All six cyanoborane adducts have been characterized by NMR and vibrational spectroscopy, elemental analysis, and single-crystal X-ray diffraction. The reduction of the cyanoborane adducts has been investigated by cyclic voltammetry and the Lewis acidity of the different cyanoboranes has been assessed using the Gutmann-Beckett method. Selected experimental data and trends are compared to theoretical ones, for example fluoride ion affinities (FIAs). 相似文献
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Osmanoğlu S Aydın M Osmanoğlu YE Dicle IY Başkan MH 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,78(5):1611-1614
An EPR study has been carried out to investigate the structure and behaviour of the free radical formed γ-irradiated l-alaninamide hydrochloride, dl-glutamic acid monohydrate and N-(2-carboxyethyl) iminodiacetic acid powders at room temperature. The observed paramagnetic species have been attributed to the CH(3)?HCONH(2), HOOCCH(2)CH(2)?HCOOH and HOOCCH(2)CH(2)N?HCH(2)(COOH)(2) radicals, respectively. Some spectroscopic properties and suggestions concerning possible structure of the radicals were also discussed in this study. 相似文献