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981.
The localised modes associated with interstitial hydrogen in the β-phases of Pd and Pd-Ag alloys have been studied by neutron energy loss at 295K, 80K and for Pd at 30K. Their energies vary little but their widths increase significantly with temperature and silver content, an effect which is ascribed to local disorder and anharmonic contributions. 相似文献
982.
Operation of most tokamaks in limited byq
a, the edge safety factor, which is usually about 2–3. In the SINP tokamak we have been able to obtain discharges withq
a values as low as 0·8. In this paper we describe our results on the setting up processes and the MHD activity associated with
these ultra lowq
a discharges. 相似文献
983.
A. Z. M. Shaifullah Chowdhury Yasuyuki Shibata Masatoshi Morita Kunimitsu Kaya Kazuhisa Hiratani 《Journal of heterocyclic chemistry》2001,38(5):1173-1177
Reaction of 2-aminopyrazine 1 with isothiocyanate, isocyanate or dithioketal reagent furnished pteridines 3,4 in good yield. Thioxo compound 3a was chlorinated, methylated and subsequently displaced by amines. A simple one-step synthesis of heterocondensed pteridines 8–13 by reaction of 2-aminopyrazine with various imino thioacetals was described 8–13 . 相似文献
984.
This note reports the detection of fluorescence from unrelaxed S1 state of benzil using Boxcar gating technique. The new emission exhibits mirror image relationship with absorption and blue shift in hydroxylic solvent. In order to ascertain wheter geometrical relaxation occurs in S1 state, intensities of fluorescence from relaxed and unrelaxed state have been compared at various temperatures. 相似文献
985.
I. Ahmad S.M. Austin B.B. Back R.R. Betts F.P. Calaprice K.C. Chan A. Chishti P. Chowdhury C. Conner R.W. Dunford J.D. Fox S.J. Freedman M. Freer S.B. Gazes A.L. Hallin T. Happ D. Henderson N.I. Kaloskamis E. Kashy W. Kutschera J. Last C.J. Lister M. Liu M.R. Maier D.J. Mercer D. Mikolas P.A.A. Perera M.D. Rhein E. Roa J.P. Schiffer T.A. Trainor P. Wilt J.S. Winfield M. Wolanski F.L.H. Wolfs A.H. Wuosmaa A. Young J.E. Yurkon 《Zeitschrift für Physik A Hadrons and Nuclei》1997,358(2):235-236
986.
J. Wilson Y.H. Chung S.R. Faber A. Pakkanen P.J. Daly I. Ahmad P. Chowdhury T.L. Khoo R.D. Lawson R.K. Smither 《Physics letters. [Part B]》1981,103(6):413-416
Studies of delayed γ-rays from the reactions 122Te(32S, p3n) and 121Sb(32S, 3n) have located high-spin excitations in 150Ho up to a 92 ± 8 ns isomer at 2625 keV. The main yrast level sequence is found to agree closely with shell model predictions (based on an inert 146Gd core) of level energies, isomeric half-life and deexcitation pathway for the configuration. 相似文献
987.
A. N. Chakravarti A. K. Chowdhury S. Ghosh K. P. Ghatak A. Dhar 《Czechoslovak Journal of Physics》1981,31(9):1037-1042
An expression is derived for the diffusivity-mobility ratio in degenerate narrow-gap ternary semiconductors in the presence of a quantizing magnetic field. With the help of this expression, the diffusivity-mobility ratio is shown, taking n-Hg1–xCdxTe as an example, to have an oscillatory dependence on a quantizing magnetic field. The influence of alloy composition on such dependence is also investigated. 相似文献
988.
989.
With the use of S(N)Ar or Ullmann reactions, the synthesis of the first lower-rim aryl ether derivatives of tert-butylcalix[4]arene is reported, as are some of their conformational properties, (1)H NMR spectra, and X-ray crystal structures. The lower-rim aryl pendants reported herein provide for new scaffolds upon which a host of other new molecular architectures can be constructed, thus extending the capability of the versatile calix[4]arenes even further. 相似文献
990.
Arindam Sengupta 《Journal of Theoretical Probability》2000,13(4):951-976
A time-space harmonic polynomial for a stochastic process M=(M
t) is a polynomial P in two variables such that P(t, M
t) is a martingale. In this paper, we investigate conditions for the existence of such polynomials of each degree in the second, space, argument. We also describe various properties a sequence of time-space harmonic polynomials may possess and the interaction of these properties with distributional properties of the underlying process. Thus, continuous-time conterparts to the results of Goswami and Sengupta,(2) where the analoguous problem in discrete time was considered, are derived. A few additional properties are also considered. The resulting properties of the process include independent increments, stationary independent increments and semi-stability. Finally, a generalization to a measure proposed by Hochberg(3) on path space is obtained. 相似文献