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991.
It is shown that the small-scale Rossby waves in a shallow rotating fluid placed in a gravitational field can generate large-scale
zonal flows by means of a two-stream-like mechanism. This mechanism is revealed under the conditions when the Lighthill instability
criterion is not satisfied.
The text was submitted by the authors in English. 相似文献
992.
We consider a class of Lagrangian theories where part of the coordinates does not have any time derivatives in the Lagrange function (we call such coordinates degenerate). We advocate that it is reasonable to reconsider the conventional definition of singularity based on the usual Hessian and, moreover, to simplify the conventional hamiltonization procedure. In particular, in such a procedure, it is not necessary to complete the degenerate coordinates with the corresponding conjugate momenta. 相似文献
993.
The research presented here concerns the simultaneous grouping of the components of a vocal sound source. McAdams [J. Acoust. Soc. Am. 86, 2148-2159 (1989)] found that when three simultaneous vowels at different pitches were presented with subaudio frequency modulation, subjects judged them as being more prominent than when no vibrato was present. In a normal voice, when the harmonics of a vowel undergo frequency modulation they also undergo an amplitude modulation that traces the spectral envelope. Hypothetically, this spectral tracing could be one of the criteria used by the ear to group components of each vowel, which may help explain the lack of effect of frequency modulation coherence among different vowels in the previous study. In this experiment, two types of vowel synthesis were used in which the component amplitudes of each vowel either remained constant with frequency modulation or traced the spectral envelope. The stimuli for the experiment were chords of three different vowels at pitch intervals of five semitones (ratio 1.33). All the vowels of a given stimulus were produced by the same synthesis method. The subjects' task involved rating the prominence of each vowel in the stimulus. It was assumed that subjects would judge this prominence to be lower when they were not able to distinguish the vowel from the background sound. Also included as stimulus parameters were the different permutations of the three vowels at three pitches and a number of modulation conditions in which vowels were unmodulated, modulated alone, and modulated either coherently with, or independently of, the other vowels. Spectral tracing did not result in increased ratings of vowel prominence compared to stimuli where no spectral tracing was present. It would therefore seem that it has no effect on grouping components of sound sources. Modulated vowels received higher prominence ratings than unmodulated vowels. Vowels modulated alone were judged to be more prominent than vowels modulated with other vowels. There was, however, no significant difference between coherent and independent modulation of the three vowels. Differences among modulation conditions were more marked when the modulation width was 6% than when it was 3%. 相似文献
994.
M. S. Tikhov 《Journal of Mathematical Sciences》1991,53(6):607-614
Limiting distributions are constructed for the log likelihood ratio of close hypotheses and for estimators from censored samples.Translated from Statisticheskie Metody Otsenivaniya i Proverki Gipotez, pp. 95–104, 1986. 相似文献
995.
We consider a two-dimensional problem concerned with static deformation of an elastic halfstrip under the action of a self-equilibrated load at its end. A method is proposed for regularization of series over homogeneous solutions in the case of non-smooth prescribed loads. An example is given of a load for which divergence obtains for a series over homogeneous solutions for the stress field at the end of the halfstrip.Translated from Teoreticheskaya i Prikladnaya Mekhanika, No. 19, pp. 111–116, 1988. 相似文献
996.
Gulis I. M. Komyak A. I. Saechnikov K. A. Tsvirko V. A. 《Journal of Applied Spectroscopy》1989,50(3):257-262
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 50, No. 3, pp. 385–391, March, 1989. 相似文献
997.
Theoretical and Mathematical Physics - 相似文献
998.
999.
1000.
M. F. Vigneras 《Inventiones Mathematicae》1989,98(3):549-563
Research at MSRI supported in part by NSF Grant DMS-812079-05 相似文献