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101.
102.
New data on weak quark decays and on weak heavy quark production are used to obtain the allowed ranges of elements of the quark mixing matrix for three or four generations of sequential quarks. The analysis yields allowed ranges for the three mixing angles in the six-quark case and for the six mixing angles in the eight-quark case. 相似文献
103.
W. Schatz P. T. Lang T. Kass M. A. Heusinger K. F. Renk 《International Journal of Infrared and Millimeter Waves》1992,13(6):853-867
In this paper we report on the determination of the spectral width of Raman gain regions for different far infrared laser gases using a metal mesh Fabry Pérot interferometer. By use of broadband pump radiation emitted from a high pressure CO2 laser we generated far infrared radiation within the Raman gain regions via stimulated Raman scattering. The spectral width of the far infrared radiation was determined using a Fabry Pérot interferometer in high interference order. We applied the method to study stimulated Raman scattering in D2O and methylfluoride at different gas pressures. 相似文献
104.
J. Grenzer E. Schomburg A. A. Ignatov K. F. Renk D. G. Pavel'ev Yu. Koschurinov B. Ja. Melzer S. Ivanov S. Schaposchnikov P. S. Kop'ev 《Annalen der Physik》1995,507(4):265-271
We report the observation of frequency multiplication of microwave radiation in a GaAs/AlAs semiconductor superlattice at room temperature. We observed, for a fundamental frequency of 9 GHz, second and third harmonic generation. We associate the harmonic generation with a nonlinear current-voltage characteristic that is determined by Bloch oscillations of electrons propagating along the superlattice axis. Our results suggest for the frequency multiplication an upper limit in the tetrahertz frequency range. 相似文献
105.
R. Baumgartner W. Eisfeld G. Pauli K.F. Renk N. Riehl 《Solid State Communications》1978,27(11):1105-1107
High-frequency acoustic phonons are detected in a ZnO crystal by phonon- induced luminescence radiation. Our experiments indicate that this radiation is caused by recombination processes of carriers captured at very shallow traps with an ionization energy of about 4 meV. Propagation of the phonons is studied by a time of flight method. 相似文献
106.
Experimental data are used to constrain the parameters of the six quark mixing model and of a composite quark model. A combined fit of the mixing angles in the Kobayashi-Maskawa scheme gives sinθ 1=0.228±0.011 and error contours around the best values sinθ 2=0.12 and sinθ 3≈0. From this, a limit of τ B >0.35×10?13 s for the mean lifetime of bottom-flavoured hadrons is obtained. For the composite quark model of Katsumata and Tomozawa, a value of τ B =(0.22?0.23)10?13 s is derived. 相似文献
107.
Experimental data on the fragmentation of charmed quarks produced in neutrino ande + e ? reactions are compared. The resulting hard fragmentation functions agree mutually. They are parametrized in two ways suggested by kinematical considerations. 相似文献