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991.
M. G. Bettoli M. Ravanelli L. Tositti O. Tubertini L. Guzzi W. Martinotti G. Queirazza M. Tamba 《Radiation Physics and Chemistry》1998,52(1-6):327-331
Decomposition by ionizing radiations of p-chlorophenol and tetrachloroethylene in synthetic water samples at about 2 mg Cl L−1, has been studied on laboratory-scale experiments. Bicarbonate/carbonate and nitrate ions, at two concentration levels (20 and 200 mg HCO3−1 and 1 and 50 mg NO3−L−) were added to synthetic samples in order to evaluate their influence on decomposition yield. At 5 kGy γ dose level, a quantitative degradation of p-chlorophenol is obtained whereas only qualitative consideration can be drawn on tetracholoroethylene. Comparative study with respect to degradation of p-cholophenol solutions (about 2 mg Cl L−1) by γ-rays and electron beam irradiation treatment at 0.5 kGy dose level, are in progress; preliminary results indicate that irradiation with γ-rays seems to be more efficient in terms of removal efficiency respect to electron beams source. 相似文献
992.
993.
994.
The Dirac equation is solved for two novel terms which describe the interaction energy between the half-integral spin of a
fermion and the classical, circularly polarized, electromagnetic field. A simple experiment is suggested to test the new terms
and the existence of radiation-induced fermion resonance. 相似文献
995.
W. Ryba-Romanowski G. Dominiak-Dzik S. Golab W. A. Pisarski I. Pracka 《Journal of Applied Spectroscopy》1995,62(5):903-909
Conclusions Nonradiative energy transfer between similar and different rare-earth ions in LiNbO3 has been evidenced for the first time. The contribution of nonradiative energy transfer to the decay of the1G4 and3H4 levels of thulium and the4S3/2 and4I13/2 levels of erbium is significant for activator concentrations of the order of several thousand ppm in LiNbO3. The excitation of higher-lying levels of both activators is transferred faster in codoped crystal to the lowest luminescent
levels, from which the luminescence in the 1–2-μm spectral region occurs. This accelerated relaxation is advantageous for
broadband optical pumping since the contribution of radiative transitions competing with the3F4−3H6 laser transition of thulium is reduced. On the other hand, it appears that erbium ions will influence adversely the efficiency
of a laser-diode-pumped LiNbO3∶Er, Tm laser operating near 1.8 μm since the part of the3H4 excitation transferred to erbium ions is emitted from the long-lived4I11/2 level of Er3+. Furthermore, the4I13/2 excitation is not transferred fully to thulium ions and is lost in4I13/2−4I15/2 emission. Lithium niobate singly doped with thulium is more promising since the cross-relaxation process that transfers the
excitation from the3H4 level to the3F4 level appears to be efficient in this host.
Published in Zhurnal Prikladnoi Spektroskopii, Vol. 62, No. 5, pp. 125–133, September–October, 1995. 相似文献
996.
D. Abbaneo P. Antilogus T. Behnke S.C. Blyth M. Elsing R. Faccini R.W.L. Jones K. Mönig S. Petzold R. Tenchini 《The European Physical Journal C - Particles and Fields》1998,4(2):185-191
Measurements of the forward-backward production asymmetry of heavy quarks in Z decays provide a precise determination of
. The asymmetries are sensitive to QCD effects, in particular hard gluon radiation. In this paper QCD corrections for and are discussed. The interplay between the experimental techniques used to measure the asymmetries and the QCD effects is
investigated using simulated events. A procedure to estimate the correction needed for experimental measurements is proposed,
and some specific examples are given.
Received: 26 February 1998 / Published online: 2 June 1998 相似文献
997.
998.
A single-change covering designSC (v, k, b) on av-setV is a sequence ofb k-sets (blocks) onV which together cover every pair of elements ofV at least once, such that two successive blocks havek–1 elements in common. It is desirable to minimizeb. Some constructions and lower bounds forb are given. 相似文献
999.
Mixed block elimination for linear systems with wider borders 总被引:1,自引:0,他引:1
The paper is about the stable solution of possibly ill-conditionedbordered linear systems. Given stable solvers for matrix A andfor AT, we prove that the Govaerts Mixed Block Elimination (BEM)method constitutes a stable solver for the matrix consistingof A or AT with a border of width 1, and hence by recursionfor a border of any width. We express the algorithm in an efficient,iterative, form. We analyse its operation count, and verifythe theory by extensive numerical experiments.
*Senior Research Associate of the Belgian National Fund of ScientificResearch NFWO. 相似文献
1000.
The thermal properties of perfluorocarbonsulfonic acid ionomer films cast from solution and their temperature-dependent far infrared spectra have been investigated. In addition to the endotherms and spectral changes associated with the loss of solvent as the films were heated, a significant exotherm has been observed and assigned to the relaxation associated with rearrangements resulting in partially crystallized phases in insoluble thermally treated membranes. © 1993 John Wiley & Sons, Inc. 相似文献