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Barbara Wolf Paul D. Mudgett Ronald D. Macfarlane 《Journal of the American Society for Mass Spectrometry》1990,1(1):28-36
A new approach to electrostatic ion deflection is described where an electrostatic particle guide (EPG) operating with reversed polarity is used to deflect ions in a cylindrical geometry about the axis of a time-of-flight mass spectrometer. The method has advantages over the standard parallel-plate deflector geometry in that it is more effective in deflecting ion beams that have a significant radial velocity component. The device is being used in 252cs Cf plasma desorption mass spectrometry (252cs Cf -PDMS) experiments in an on/off mode to record neutral particle spectra and in a synchronized pulsed mode to reduce the magnitude of the uncorrelated background in the time-of-flight spectrum. Radial distribution functions have been measured for various EPG voltages. Its use as a background suppression technique is demonstrated by using the 252cs Cf-PDMS spectrum of insulin. (28-36) 相似文献
995.
996.
V. A. Zazhigalov Yu. P. Zaitsev V. M. Belousov N. Wüstneck H. Wolf H. Seeboth 《Reaction Kinetics and Catalysis Letters》1986,30(1):47-53
Mechanism of n-butane oxidation of -VOPO4 has been studied in pulse fixed and vibrofluidized catalyst bed reactors by the pulse microcatalytic method. It has been established that the rates of catalysis and reduction are similar, which indicates a reduction-oxidation mechanism for butane conversion and maleic anhydride formation. In the course of catalysis the reaction products are formed largely at the expense of catalyst oxygen and -VOPO4 reduces to (VO)2P2O7.
- -VOPO4. , - . , , , -VOPO4 (VO)2P2O7.相似文献
997.
Joachim Heitbaum Wolf Vielstich 《Angewandte Chemie (International ed. in English)》1974,13(11):683-696
The investigation of electrode processes calls for the use of methods that yield information on the reaction mechanism and the reaction rate, on the nature and stability of intermediates, and on adsorption processes at the electrode. It is no longer enough to record current-voltage curves or charging curves. In addition to the potentiostatic scan method, other methods that have proved useful for the investigation of electrode kinetics are the rotating disc electrode in particular, and to a smaller extent AC polarography. Intermediates can be identified with rotating double electrodes and by ESR spectroscopy or mass spectrometry. Adsorption processes on electrode surfaces can be studied by optical methods or by radioactive tracer methods. 相似文献
998.
999.
C. Lewin D. Denegri A. Givernaud M. Loret L. Mosca J. Saudraix H. Grässler J. Klugow U. Kriegel M. Walter E. De Wolf F. Verbeure D. R. O. Morrison F. A. Triantis C. Dujardin F. Grard Yu. Arestov M. Boglyubsky V. Bumazhnov P. V. Chliapnikov V. M. Perevoztchikov A. P. Vorobjev H. Dibon France-Soviet Union Collaboration CERN-Soviet Union Collaboration 《Zeitschrift fur Physik C Particles and Fields》1980,3(4):275-284
Results are presented onK + p andK ? p elastic scattering at 32.1 GeV/c in the |t| interval 0.06–1.4 GeV2. The samples contain approximately 15,000 events each and are obtained in the MIRABELLE bubble chamber at the Serpukhov accelerator. The |t| distributions are parametrized by quadratic exponential formsdσ/dt=A exp (bt+ct 2). The total elastic cross sections, obtained by integrating the fitted distributions, are (2.39±0.07) mb and (2.57±0.10) mb inK + p andK ? p interactions, respectively. A cross-over between theK + p andK ? p differential cross sections is found at |t c |=0.17±0.02 GeV2. The hypothesis of geometric scaling becomes valid somewhere between 32 and 70 GeV/c forK + p interactions, and is trivially verified forK ? p scattering. Finally, an impact parameter analysis of the difference betweenK ? p andK + p elastic amplitudes is presented. 相似文献
1000.