巻号一覧
37 巻, 2 号
選択された号の論文の4件中1～4を表示しています
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報文
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Sakuo Matsui, Hikaru Inoue, Hiromitsu Nakabushi, Toshihiro Ueda, Yasuk ...1989 年 37 巻 2 号 p. 97-107
発行日: 1989年
公開日: 2007/05/01
ジャーナル フリーMethod of comparing the positron mass with the electron mass by using crossed fields is discussed on the basis of the relativistic calculation to the second order. Remodeling of a high resolution magnetic β-ray spectrometer into a positron-electron mass spectrometer is proposed. The crossed fields in the β-ray spectrometer equipped with a pair of cylindrical electrodes gives the mass dispersion of 1.3 μm/ppm at the optical circle of 0.75 m radius. Simulated peak profiles are presented for the monochromatic source of electrons or positrons and the β-ray source that emits them simultaneously in the continuous distribution.抄録全体を表示PDF形式でダウンロード (618K) -
Susumu Tajima, Kazuo Ogino, Seiji Tobita, Ikuo Sakai1989 年 37 巻 2 号 p. 109-116
発行日: 1989年
公開日: 2007/05/01
ジャーナル フリーThe structures of the decomposing intermediate ions, [C7H8N]+ generated from a variety of toluidine and aniline derivatives were examined with the aid of kinetic energy release (KER).
Among these ions, [C7H8N]+ ions generated from o-, m-, and p-toluidines and from 2, 3-, 3, 4-, and 2,6-xylidines are assigned to aminotropylium ion (a). The ions from o-, m-, and p-ethylanilines are interpreted as the corresponding aminobenzyl ion (b). A methyliminocy-clohexadiene ion structure (c) is postulated for the intermediate ion from N-methyl-o-, m-, and p-toluidines. The ion from N-ethylaniline is elucidated to be anilinomethene ion (d).
These are in agreement with the results for the non-decomposing (stable) [C7H8N]+ ions, which were obtained by experimental heats of formation.抄録全体を表示PDF形式でダウンロード (479K) -
山本 正夫, 堀口 雅枝, 横田 佳子, 田中 基子, 竹内 孝江, 岩井 薫, 竹村 富久男1989 年 37 巻 2 号 p. 117-128
発行日: 1989年
公開日: 2007/05/01
ジャーナル フリーWe have studied the fragmentation of four lower alkylsilanes (CH3SiH2C2H5, CH3SiH2-C3 H7, (C2H5)2SiH2, CH3SiH2C4H9) appeared in EIMS. The main fragment ions of m/z 45 (CH3 SiH2+) of ethylmethylsilane and methylpropylsilane were produced by the cleavage of the Si-C bond on the longer alkyl chain side, respectively, and the large fragment ion of m/z 59 (C2H5 SiH2+) of diethylsilane was also produced by the cleavage of Si-C bond. The base peak of butylmethylsilane was m/z 73 (CH3SiH2CH2CH2+). The H-loss ions [M-H]+ and the H2-loss ions [M-H2]+ of CH3SiH2C2H5 and CH3SiH2C3H7 were very abundant, especially at low ionization energies. The optimized geometries of neutral molecules and molecular cations of methylpropylsilane and butylmethylsilane were calculated by using ab initio MO method. The Si-C bond on the larger alkyl group side of molecular cation was lengthened from 1.87Å to 2.17Å and the net charge on Si-atom was positive. This showed that the Si-C bond was easy to cleavage and the fragment containing Si-atom to have a positive charge.抄録全体を表示PDF形式でダウンロード (480K) -
Mitsuo Takayama, Toshio Fukai, Taro Nomura1989 年 37 巻 2 号 p. 129-140
発行日: 1989年
公開日: 2007/05/01
ジャーナル フリーPositive ion FAB mass spectra of prenylated flavonoids were compared with the corresponding EI and CI mass spectra, and some fragment ions similar to those in the EI mass spectra and CI-like intense protonated molecules (M+H)+ were recognized. Major fragmentations in the EI and FAB mass spectra were discussed. It was concluded that FAB ionization possesses both features, EI-like hard ionization and CI-like soft ionization.抄録全体を表示PDF形式でダウンロード (533K)
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