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101.
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Ohne Zusammenfassung
Deutsch von K. Popp (Leipzig). 相似文献
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The single-colour photoionization spectrum of atomic uranium is recorded in the spectral region from 366 to 371 nm. Most of the 43 observed resonances are found to be associated with the two-step photoionization process. Based on known energy levels seven new transitions have been proposed. Three of these transitions originate either from the ground state or the lowest metastable state at 620 cm–1. 相似文献
107.
The low lying levels in51Cr have been populated by51V (p, ny)51Cr reaction. The angular distribution of the ground state electromagnetic transitions from 1165, 1353, 1479 and 1557 keV states have been measured. The results are compared with the Hauser-Feshbach model of the statistical theory of nuclear reactions. The spins for the levels at 1165, 1479 and 1557 keV are shown to be 9/2?, 11/2? and 5/2? respectively. 相似文献
108.
Alain Leborgne Shadi Lal Malhotra Louis-Philippe Blanchard 《Journal of polymer science. Part A, Polymer chemistry》1976,14(12):2853-2866
The polymerization of 1,2-butylene oxide initiated with triphenylmethyl hexafluoroarsinate in the ?20 to +25°C temperature range with 1,2-dichloroethane as solvent is characterized by a rapid nonstationary initial stage. This is followed by a second slower stage, during which the disappearance of monomer is first-order with respect to its concentration. The conversion of monomer at the end of the first stage is related to the initial catalyst concentration but not to the initial monomer concentration. Invoking the hypothesis of an instantaneous initiation reaction, the experimental results lead to the conclusion of the existence of a unimolecular termination step. Propagation-to-termination rate constant ratios yield a propagation–termination activation energy difference of 5.9 kcal/mole. The termination step proposed is thought to involve the formation of stable macrocyclic oxonium ions. These, in turn, can reactivate the polymerization by an intramolecular reaction leading to the formation of new active centers. An energy of activation of 8.7 kcal/mole was calculated for this reactivation. GPC analyses of the reaction products recovered at the end of the first stage revealed the presence of large proportions of oligomers. Based on kinetic data, the formation of oligomers is explained by a backbiting process similar to the reactivation reaction suggested for the initiation of the second stage. 相似文献
109.
An exact solution of Einstein-Maxwell-Yukawa field equations has been obtained in a space-time with a static metric. A critical analysis reveals that the results previously obtained by Patel [9], Singh [10], and Taub [11] are particular cases of our solution. The singular behavior of the solutions has also been discussed in this paper. Further, extending the technique developed by Janis et al. [12], for static fields, to the case of nonstatic fields, an exact time-dependent axially symmetric solution of EMY fields has been obtained. Our solution in the nonstatic case is nonsingular in the sense of Bonnor [15] and presents a generalization of the results obtained by Misra [7] to the case when a zero-mass scalar field coexists with a source free electromagnetic field. 相似文献
110.
Alok Kumar Rastogi A. K. Tiwari R. P. Shrivastava 《International Journal of Infrared and Millimeter Waves》1993,14(7):1445-1453
The dielectric optical wave guide is finding growing attention at millimeter wave frequencies. However the dielectric optical waveguide radiates at bends and thus transmission loss increases. These radiations are in the outword direction of bends. This output radiation at output bends arises due to change in phase velocities of the propagating wave at the centre of the dielectric guide and the phase velocity at the outer surface of the dielectric guide. A unique methiod is suggested to avoid these radiation losses.Experimental results are also shown at microwave frequencies. 相似文献