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141.
The fine structure of the Rayleigh line wing depolarized spectrum in a form of a triplet caused by the light scattering by transverse hypersonic waves was detected in a critical solution with a closed stratification region at low temperatures. The propagation velocity of transverse hypersound and its absorbance were measured. The temperature dependence of the shear modulus in solution was calculated. The temperature dependence of the shear modulus was compared to temperature dependences of limiting bulk elastic moduli. The results obtained suggest that the solution structure changes in passing through the stratification region at changing temperature. 相似文献
142.
R. Stanoeva V. Bradnova S. Vokál P. I. Zarubin I. G. Zarubina N. A. Kachalova A. D. Kovalenko A. I. Malakhov G. I. Orlova N. G. Peresadko P. A. Rukoyatkin V. V. Rusakova E. Stan M. Haiduc S. P. Kharlamov I. Tsakov T. V. Shchedrina 《Physics of Atomic Nuclei》2007,70(7):1216-1221
The results obtained by studying the charge topology of fragments produced in the peripheral dissociation of relativistic 8B nuclei in emulsion are presented. Fifty-five events of the peripheral dissociation of a 8B nucleus in events where there was no production of target-nucleus fragments and mesons (“white stars”) were selected. A leading contribution of the 8B → 7Be + p mode, which has the lowest energy threshold, was revealed on the basis of these events. Information about the branching ratios for dissociation modes characterized by a higher multiplicity was obtained. The dissociation of the 7Be core in 8B bears resemblance to the dissociation of a free 7Be nucleus. The transverse-momentum distributions of fragments originating from the 8B → 7Be + p dissociation mode were obtained. For these distributions, a small mean value of 〈P*T〉 = 52 ± 5 MeV/c in the c.m. frame suggests a low binding energy of the outer proton in the 8B nucleus. An indication of a strong azimuthal correlation of the fragments 7Be and p was found. 相似文献
143.
The propagation velocity and absorbance of longitudinal hypersound weremeasured in a wide temperature range by scattered light spectra in pure guaiacol. The Rayleigh line wing spectrum was studied and the relaxation time of anisotropy fluctuations was determined. The temperature dependence and value of the molecular viscosity of guaiacol were determined from the data on the Rayleigh line wing width. 相似文献
144.
145.
The interaction of a Gulyaev-Bluestain surface wave with a granular high-temperature superconducting (HTSC) medium has been
investigated. For piezoelectrics of symmetry 4mm and 6mm, dispersion equations have been derived that describe the characteristics
of surface acoustic waves (SAWs). The temperature dependences of the SAW attenuation and phase have been calculated forZnO andBa
2Si2TiO3 crystals. It is shown that at temperatures higher than the critical temperature an attenuation jump and a phase shift are
observed. The effect intensifies with increase in the electromechanical coupling coefficient and with decrease in the thickness
of the HTSC film. For theBa
2Si2TiO3 crystal the attenuation jump and phase shift are11 dB/cm and38 deg/cm, respectively, at a frequency of820 MHz. The results obtained can also be generalized for periodic HTSC structures and can be used to design frequency-selective
devices and fast-response bolometric photodetectors.
Tomsk State University of Control Systems and Radioelectronics. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika,
No. 4, pp. 49–52, April, 1999. 相似文献
146.
147.
148.
N. N. Strunina T. A. Kovalenko B. T. Baisova L. N. Adeeva 《Journal of Applied Spectroscopy》2009,76(2):257-259
Quantitative atomic emission spectral analysis was used to study the rare-earth content in sapropel and the rare-earth distribution
over the isolated fractions. The conditions for determination of Ce, Y, and La (analytical lines, arc discharge current, exposure
time) were selected empirically. We calculated the metrological characteristics of the proposed technique. We have shown that
in Tyurin fractionation, the nonhydrolyzable residue fraction has the highest concentrations of these elements.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 76, No. 2, pp. 273–276, March–April, 2009. 相似文献
149.
150.
A.L. Dobryakov J.L. Prez Lustres S.A. Kovalenko N.P. Ernsting 《Chemical physics》2008,347(1-3):127-138
Femtosecond transient UV/vis absorption spectra of molecules in solution show vibronic structure initially while pump and probe pulses overlap, superimposed on bands which broaden and shift on several time scales. Third-order perturbation theory is used simulate and understand such spectra under experimental conditions, i.e., with chirped pump pulses and 40–80 fs pump/probe correlation time. The electronic system is coupled to a solvent bath whose fluctuations enter through a lineshape function g(t). This approach has two advantages. (i) In the general case when g(t) is modelled realistically it provides a distinction of coherent and sequential contributions to early transient spectra. The time-zero stimulated emission band can be extracted, giving access to the relaxation function for the emission frequency. (ii) For limiting forms of g(t) corresponding to the Bloch approximation and to inhomogeneous broadening the threefold time integrals underlying the theory reduce to a single integral. In such cases the lineshape formulation of transient absorption spectra can be used for data fitting. 相似文献