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91.
Gonnelli RS Daghero D Ummarino GA Stepanov VA Jun J Kazakov SM Karpinski J 《Physical review letters》2002,89(24):247004
We present the results of the first directional point-contact spectroscopy experiments in high-quality MgB2 single crystals. Because of the directionality of the current injection into the samples, the application of a magnetic field allowed us to separate the contributions of the sigma and pi bands to the total conductance of our point contacts. By using this technique, we were able to obtain the temperature dependency of each gap independent of the other. The consequent, strong reduction of the error on the value of the gap amplitude as a function of temperature allows a stricter test of the predictions of the two-band model for MgB2. 相似文献
92.
The energy of plasma oscillations of free charge carriers in bismuth crystals ?ωp can be qual to the band gap at the L point of the Brillouin zone E gL as a result of doping with an acceptor impurity. Variation in the edge shape and splitting of the minimum in the plasma reflection are observed in experimental studies of reflection under normal incidence of radiation on the crystal. An analysis of the totality of available experimental data shows that the above special features are caused by interaction of elementary excitations (such as the plasma oscillations) with band-to-band transitions. It became possible for the first time to ascertain the composition of the bismuth crystals for which the condition ?ωp=E gL is satisfied and observe the variation in the characteristics of the plasma oscillations of free charge carriers, which occurs as a result of electron-plasmon interaction. 相似文献
93.
We suggest a novel method for significant improvement of fiber Bragg grating (FBG) spectral characteristics based on compensation of repeatable errors during the grating writing process. The method is based on an open loop scheme in which a test grating is written first and then a corrected design is obtained and implemented by writing another (compensated) grating. The results are presented for a FBG dispersion compensator. 相似文献
94.
V. Burjan J. Cejpek J. Fojtu V. Kroha D. V. Aleksandrov B. G. Novatskii D. N. Stepanov 《Zeitschrift für Physik A Hadrons and Nuclei》1996,356(1):281-286
The analogue of the 0+ ground state in118Sn has been observed in the compound nucleus118Sb through117Sn(p,nγ)117Sb reaction. The neutron decays of this analogue resonance have been studied from the deexcitingγ-rays of the residual nucleus117Sb. From off resonance excitation functions, spin assignments have been made to states in117Sb, on the basis of Hauser-Feshbach formalism. The resonance parameters of the isobaric analogue resonance have been determined, including the total, proton and neutron decay widths. 相似文献
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Using birefringent crystals such as LiNbO3: Fe, reading and writing of holograms at different wavelengths and so nondestructive readout of information may be accomplished. 相似文献
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