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61.
MA Freitas SR Dillon RC Dougherty AG Marshall 《Rapid communications in mass spectrometry : RCM》1999,13(15):1622-1625
The self-chemical ionization of diethylzinc is examined by Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry and semiempirical molecular orbital calculations. Electron impact of diethylzinc neutral produces the radical cation, C(4)H(15)Zn(+) (m/z x 122), which reacts further with the neutral (C(2)H(5))(2)Zn to give the following product ions: Zn(+) (m/z x 64), C(2)H(5)Zn(+) (m/z x 93), C(4)H(9)Zn(+) (m/z x 121), C(4)H(11)Zn(2)(+) (m/z x 187), and C(6)H(15)Zn(2)(+) (m/z x 215). To determine the structure and pathways for production of these ions, monoisotopic (12)C(4)H(15)(64)Zn(+), (64)Zn(+) and (12)C(2)H(5)(64)Zn(+) were individually isolated and reacted with the neutral background. We also performed semiempirical molecular orbital calculations (ZINDO/1). The molecular orbital calculations and experimental data are consistent in predicting that the ethyl group on the diethylzinc cation carries the positive charge. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
62.
Nonlinear Dynamics - Port Knocking is a method for authenticating clients through a closed stance firewall, and authorising their requested actions, enabling severs to offer services to... 相似文献
63.
K. -H. Münch A. Kratzer G. M. Kalvius K. Maier J. Major M. Hampele TH. Pfiz 《Hyperfine Interactions》1994,87(1):1049-1054
A technique to handle the high data rates of a pulsed beam as available at KEK and RAL is described. Different detector concepts, which would also allow to increase the initial asymmetry have been tested and are presented.This work was supported by the German Federal Minister for Research and Technology (Bundesminister für Forschung und Technologie [BMFT]) under Contract Nr. 03KA2-TUM-4. 相似文献
64.
A. Fritzsche M. Hampele D. Herlach K. Maier J. Major L. Schimmele A. Seeger W. Staiger W. Templ C. Baines 《Hyperfine Interactions》1991,64(1-4):691-700
The spin-precession frequencies and the transverse spin relaxation rates of positive mouns (μ
+) have been measured on two elastically strained α-Fe single crystal platelets as well as on an unstrained reference α-Fe
crystal at temperatures down to 2.7 K in applied magnetic field 0≤B
appl≤3 T. The drastic effects of the strains may be qualitatively understood in terms of their influence on both the magnetic
domain structure and theμ
+ energies at the various interstitial sites. This leads to the conclusion that at low temperaturesμ
+ in α-Fe occupy configurations related to octahedral interstitials with dipolar fieldB
dip=0.70 T. 相似文献
65.
We report on the systematic open-aperture Z-scan characterization of the two-photon absorption properties in one of the most efficient solid-state Raman frequency shifters, the crystal potassium gadolinium tungstate [KGd(WO4)2]. The two-photon absorption coefficient was determined in the 370-600-nm wavelength range, with the highest value found to be approximately 1.9 cm/GW at 370 nm. Nonlinear losses are crucial in determining the conversion efficiency of the stimulated Raman scattering process when it is excited with ultrashort laser pulses with photon energy exceeding half of the bandgap. In addition, the results were analyzed within the context of a simple two-parabolic-band theoretical model to yield an effective bandgap energy value for the crystal. 相似文献
66.
We report an efficient transient stimulated Raman conversion of high-energy picosecond pulses at 1350 nm into the eye-safe 1500-nm wavelength range by use of a KGd(WO4)2 crystal. The conversion efficiency into either 1503- or 1537-nm radiation (767- or 901-cm(-1) Raman modes, respectively) is measured to be approximately 10% in a single-pass configuration. The transient Raman gain coefficient is found to be approximately 0.8 cm/GW. Simultaneous generation of multiple Raman lines is also observed. 相似文献
67.
68.
J.A. Charlesworth R.L. Sekulin M.J. Emms J.B. Kinson L. Riddiford B.J. Stacey M.F. Votruba P.L. Woodworth I.G. Bell M. Dale J.V. Major 《Nuclear Physics B》1973,65(2):253-289
The production of ?0 and f0 mesons has been studied using a sample of 15485 fits to the reaction π+d → pspπ+π? at 4 GeV/c. Results are presented on the spin structure and production mechanisms of these resonances. An Estabrooks and Martin analysis has been carried out in the ?0 region, giving results similar to those obtained in their analysis of 17.2 GeV/c data. Natural parity exchange is less important at our momentum, however. In the case of f0 production, we find evidence for the presence of s-, p- and d-waves in the π π system. Averaging all events in the f0 peak, the s- and d-waves are found to be close in phase. The f0 production mechanism has been investigated using a positivity analysis of the complete J = 0, 1, 2 density matrix, and the same general features are observed as are seen in ?0 production. However, the unnatural parity exchange component is found to be even more dominant in f0 production than in ?0 production. Our results are compared with the predictions of various models. 相似文献
69.
70.
A partial wave analysis of the (3π)0 system from the charge exchange reaction π+n→π+π−πop AT 4 GeV/c
M.J. Emms G.T. Jones J.B. Kinson B.J. Stacey M.F. Votruba P.L. Woodworth I.G. Bell M. Dale J.V. Major J.A. Charlesworth D.J. Crennell R.L. Sekulin 《Physics letters. [Part B]》1975,60(1):109-112
From a partial wave analysis of the (3π)o state in the charge exchange reaction π+n→π+π?πop, we observe strong unnatural parity as well as natural parity production. The observed strong unnatural parity states are identified with well-established resonances. The unnatural parity production is consistent with Reggeized Deck model predictions, with the exception of the I = 1, JP = 1+ state. Here there is no evidence for A1 production at ~1.1 GeV, but the data could support resonance production at higher masses. 相似文献