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Comparative Studies on Mass Spectrometric fragmentation of Linear Chiral Secondary Alcohols (R)-1-(4-Alkylphenyl) and (R)-1-(4-Alkoxyphenyl/Alkylthiophenyl) Alcohols

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Chemical Research in Chinese Universities 2006年第3期22卷 347-350页

作者： ZHANG Qi-han SU Xian-bin XU Jia-xi Key Laboratory of Bioorganic Chemistry and Molecular Engineering College of Chemistry and Molecular Engineering Peking University Beijing 100871 P.R. China

Mass spectrometric behaviour of （R） -1- （ 4-alkylphenyl ） alcohols, 1- （4-alkoxylphenyl） alcohols, and 1- （4-alkylthiophenyl） alcohols were studied with the aid of mass-analyzed ion kinetic energy spectrometry under electron impact ionization. All the title compounds show a tendency to eliminate a water molecule to form alkene ions and undergo an a-cleavago to produce protonated aldehyde ions by the loss of alkyl radicals. Except these two common fragment ions, they also show some different fragmentations due to with or without oxy/thioether-linkage.

关键词： 1-(4-Alkylphenyl) alcohol 1-(4-Alkoxylphenyl) alcohol 1-(4-Alkylthiophenyl) alcohol Electron impact ionization fragmentation mechanism Mass spectrometry

Mass spectrometric studies of cis- and trans-1a,3-disubstituted-1, 1-dichloro-4-formyl-1a ,2,3,4-tetrahydro-1H-azirino [ 1,2-a] [1,5] benzodiazepines

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Chinese Journal of Chemistry 2000年第3期18卷 368-372页

作者：许家喜张新宇金声 College of Chemistry and Molecular Engineering Peking University Beijing 100871 China

The mass spectrometric behaviour of four cis- and trans-1a, 3-disuhsdtuted-1,1-dichloro-4-formyl-1a,2,3,4-tetrahydro-1H-azirino[1, 2-a] [1, 5]benzodiazepines has been studied with the aid of mass-analysed ion kinetic energy spectrometry and exact mass measurements under electron impact ionization. All compounds show a tendency to eliminate a chlorine atom from the aziridine ring, and then eliminate a neutral propene or styrene from the diazepine ring to yield azirino[1, 2b][1,3] benzimidazole ions. These azirino[1,2-a][1,5]benzodiazepines can also eliminate HCl, or Cl plus HCl simultaneously to undergo a ring enlargement rearrangement to yield 1,6-benzodiazocine ions, which further lose small molecular fragments, propyne or phenylacetylene, with rearrangement to give quinoxaline ions.

关键词： 1H-azirino[1,2-a]benzodiazepine electron impact ionization fragmentation mechanism mass spectrometric studies ring enlargement rearrangement

Photodissociation of Cycloketones by Ultraintense Femtosecond Laser Pulses

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Chinese Chemical Letters 2000年第6期11卷 545-548页

作者： Cheng Yin WU Yi Jia XIONG Jin Xiong WANG Fan Ao KONG (Institute of Chemistry, The Chinese Academy of Sciences, Beijing 100080) Chinese Acad Sci Inst Chem Beijing 100080 Peoples R China

Photodissociation of cyclopentanone (C5H8O) and cyclohexanone (C6H10O) was studied with 800nm, 50fs laser pulse at intensities of 5.0 - 13.0x10(13) W/cm(2). A time of flight mass spectrometer was employed to detect the ion signals. Parent ions dominated at lower laser intensities. fragmentation of the parent ions increases with increasing laser intensity and molecular size. The fragmentation mechanism was discussed.

关键词： intense field femtosecond laser fragmentation mechanism

Discrimination of Structural Isomers of Aromatic Compounds with EI Mass Spectra and Their Ionization Efficiency Curves of Dehydrogenated Fragment Ions

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Chinese Chemical Letters 1998年第10期9卷 961-964页

作者： Zeper ABLIZ Li Jun LI Teruo KAN and Toyotoshi UEDA(Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050Tokyo Metropolitan Research Laboratory of Public Health, Shinjuku-ku, Tokyo 160, JapanDepa Chinese Acad Med Sci Inst Mat Med Beijing 100050 Peoples R China Peking Union Med Coll Beijing 100050 Peoples R China Tokyo Metropolitan Res Lab Publ Hlth Shinjuku Ku Tokyo 160 Japan Meisei Univ Dept Chem Hino Tokyo 191 Japan

The mechanism of ionization and fragmentation for terphenyl (diphenylbenzene) with three structural ring isomers (ortho-, meta- and para-), and stilbene (1,2-diphenylethylene) with two geometrical isomers (trans- and ... 详细信息

关键词： terphenyl and stilbene EI mass spectrometry ionization efficiency curve overcrowding effect fragmentation mechanism

Structural Effect on Electron Impact Decomposition of 1,3-and 1,4-Cyclohexane Dinitrites

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Chinese Journal of Chemical Physics 2021年第4期34卷 429-435,I0002,I0003,I0011,I0012页

作者： Tai Qin Jun-fei Xue Lily Zu College of Chemistry Beijing Normal UniversityBeijing 100875China

Alkyl dinitrites have at-tracted attention as an im-portant type of nitrosating agent and a pollution source in *** reac-tivity and chemistry of alkyl dinitrites induced by the two ONO functional groups are relatively *** this work,decompositions of 1,3-cyclohexane dinitrite and 1,4-cyclohexane dinitrite are studied by electron impact ionization mass spectroscopy(EI-MS).Apart from NO^(+)(m=z=30),fragment ions m=z=43 and 71 are the most abundant for the 1,*** the other hand,fragments m=z=29,57,85,and 97 stand out in the EI-MS spectrum of 1,*** dissociation mechanisms of the two dinitrites are proposed by theoretical *** results reveal that the ring-opening of 1,3-cyclohexane dinitrite mainly starts from the intermediate ion(M-NO)^(+)by cleavage of twoαC-βC *** 1,4-cyclohexane dinitrite,in addition to the decomposition via intermediate(M-NO)^(+),cleavage ofβC-βC bonds can occur directly from the parent cation(M)^(+).The results will help to understand the structural related chemistry of alkyl dinitrites in atmosphere and in NO transfer process.

关键词： Cyclohexane dinitrite Structural isomers Substitution position Electron impact decomposition fragmentation mechanism

Stress distribution and its influencing factors of bottom-hole rock in underbalanced drilling

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Journal of Central South University 2018年第7期25卷 1766-1773页

作者： ZHANG Ran LI Gen-sheng TIAN Shou-ceng Key Laboratory of Fluid and Power Machinery of Ministry of Education Xihua UniversityChengdu 611743China State Key Laboratory of Petroleum Resource and Prospecting China University of PetroleumBeijing 102249China

The underbalanced drilling has been widely used due to its advantages of high drilling efficiency and low cost etc., especially for hard formation drilling. These advantages, however, are closely related to the stress state of the bottom-hole rock; therefore, it is significant to research the stress distribution of bottom-hole rock for the correct understanding of the mechanism of rock fragmentation and high penetration rate. The stress condition of bottom-hole rock is very complicated while under the co-action of overburden pressure, horizontal in-situ stresses, drilling mud pressure, pore pressure and temperature etc. In this paper, the fully coupled simulation model is established and the effects of overburden pressure, horizontal in-situ stresses, drilling mud pressure, pore pressure and temperature on stress distribution of bottom-hole rock are studied. The research shows that： in air drilling, as the well depth increases, the more easily the bottom-hole rock is broken; the mud pressure has a great effect on the bottom hole rock. The bigger the mud pressure is, the more difficult to break the bottom-hole rock; the max principle stress of the bottom-hole increased with the increasing of mud pressure, well depth and temperature difference. The bottom-hole rock can be divided into 3 regions respectively according to the stress state, 3 direction stretch zone, 2 direction compression area and 3 direction compression zone; the corresponding fragmentation degree of difficulty is easily, normally and hardly.

关键词： thermo-poroelastoplasticity bottom-hole rock stress fully coupled numerical solution fragmentation mechanism

Discussion on the Application of LS-DYNA in Superfine Grinding of Wheat Bran

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Grain & Oil Science and Technology 2018年第3期1卷 138-144页

作者： CHENG Min LIU Baoguo CAO Xianzhou School of Mechanical and Electrical Engineering National Engineering Laboratory of Wheat & Corn Further Processing Henan University of Technology

Superfine grinding, involving the fragmentation mechanism of wheat bran cell tissue, is being employed by milling industry. In order to determine the effect of wheat bran cell tissue on the fragmentation mechanism when using superfine grinding,a technical scheme of the nonlinear finite element numerical simulation method based on LS-DYNA is proposed in this *** physiological characteristics of wheat bran structural layers including outer pericarp, intermediate layer and aleurone layer are examined first, and then the mechanical properties of wheat bran structural layers and their effects on the super fine grinding process are analyzed. Secondly, the explicit time integration algorithm of LS-DYNA is introduced, and the application feasibility of LS-DYNA in the analysis of wheat bran superfine grinding mechanism is discussed. Finally, the specific application of LS-DYNA in the determination of grinding form and load, the selection and design of the grinding media and the selection of grinding temperature are discussed in detail in the process of superfine grinding for wheat bran cell tissue. The above research provides a theoretical basis for selecting and developing the equipment and technology suitable for wheat bran superfine grinding, and lays a theoretical foundation for enhancing the quality and efficiency of wheat bran superfine grinding.

关键词： LS-DYNA Wheat bran Superfine grinding fragmentation mechanism Cell tissue

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