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Search Results: 1 - 10 of 223857 matches for " R. Khasanov "
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Super-Compressibility Phenomenon  [PDF]
Kholmurad Khasanov
Journal of Modern Physics (JMP) , 2013, DOI: 10.4236/jmp.2013.42028

Super-compressibility and density jump of high-energy field in gases and in condensed matters are established as source of high density energy field in the nozzle with central cone. The nozzle is resonator and dynamic emitter of the fields in spiraled subsonic and supersonic jets. The values of super-accelerations are estimated as result of internal energy changing and decreasing during adiabatic expansion of the gas. Super accelerations in this field provide high energy radiation in continuous media. These phenomena can serve as basis for creation of new sources of energy.

Emission of High Energy during Super-Compressibility of Supersonic Jets  [PDF]
Kholmurad Khasanov
Open Journal of Fluid Dynamics (OJFD) , 2012, DOI: 10.4236/ojfd.2012.24018
Abstract: New source of light emission of high energy is found due to arising of instability in supersonic jets. These phenomena are observed in gas jets flowing from the nozzle with a central cone. It leads to high accelerations of the molecules, ions and elementary particles. The emission spectra of the jets are obtained. Decoding of the spectra allowed us to define inverted population of rotational and vibrational levels, electrons temperature, rotational and vibrational temperatures for molecular ions. Internal energy decreasing provides the instability and gas volume decreasing due to internal forces; super-compressibility is result of it; its produce high density of light energy emission in various continuous media.
The Light during Gravitational Super-Compressibility  [PDF]
Kholmurad Khasanov
Journal of Modern Physics (JMP) , 2013, DOI: 10.4236/jmp.2013.44066

The interaction of electromagnetic and gravitational fields and gravitational super-compressibility were investigated experimentally. Dynamic emitter provides conditions for the generation of eigenfunctions with eigenvalues for the various fields, including: acoustic, gravitational and electromagnetic. We observe the gravitational waves in gas flowing from the dynamic emitter and their interaction with electromagnetic waves. The gravitational field energy was decreasing when electromagnetic field was emitted through the excitation of condensed medium. The direction of maximum change of the emitted energy of excited medium was strongly opposed to gravity vector at that point. The frequency of radiation against the gravity vector in given point of space exceeded radiation frequency of same source in opposite direction.

Pressure effect on the in-plane magnetic penetration depth in YBa_2Cu_4O_8
R. Khasanov,J. Karpinski,H. Keller
Physics , 2004, DOI: 10.1088/0953-8984/17/15/016
Abstract: We report a study of the pressure effect (PE) on the in-plane magnetic field penetration depth lambda_{ab} in YBa_2Cu_4O_8 by means of Meissner fraction measurements. A pronounced PE on lambda_{ab}^{-2}(0) was observed with a maximum relative shift of \Delta\lambda^{-2}_{ab}/\lambda^{-2}_{ab}= 44(3)% at a pressure of 10.2 kbar. It arises from the pressure dependence of the effective in-plane charge carrier mass and pressure induced charge carrier transfer from the CuO chains to the superconducting CuO_2 planes. The present results imply that the charge carriers in YBa_2Cu_4O_8 are coupled to the lattice.
Evidence for charged critical behavior in the pyrochlore superconductor RbOs2O6
T. Schneider,R. Khasanov,H. Keller
Physics , 2004, DOI: 10.1103/PhysRevLett.94.077002
Abstract: We analyze magnetic penetration depth data of the recently discovered superconducting pyrochlore oxide RbOs2O6. Our results strongly suggest that in RbOs2O6 charged critical fuctuations dominate the temperature dependence of the magnetic penetration depth near Tc. This is in contrast to the mean-field behavior observed in conventional superconductors and the uncharged critical behavior found in nearly optimally doped cuprate superconductors. However, this finding agrees with the theoretical predictions for charged criticality and the charged criticality observed in underdoped YBa2Cu3O6.59.
Pressure effects on the superconducting properties of YBa_2Cu_4O_8
R. Khasanov,T. Schneider,H. Keller
Physics , 2005, DOI: 10.1103/PhysRevB.72.014524
Abstract: Measurements of the magnetization under high hydrostatic pressure (up to 10.2 kbar) in YBa_2Cu_4O_8 were carried out. From the scaling analysis of the magnetization data the pressure induced shifts of the transition temperature T_c, the volume V and the anisotropy \gamma have been obtained. It was shown that the pressure induced relative shift of T_c mirrors essentially that of the anisotropy. This observation uncovers a novel generic property of anisotropic type II superconductors, that inexistent in the isotropic case.
Comparison of different methods for analyzing $μ$SR line shapes in the vortex state of type-II superconductors
A. Maisuradze,R. Khasanov,A. Shengelaya,H. Keller
Physics , 2008, DOI: 10.1088/0953-8984/21/7/075701
Abstract: A detailed analysis of muon-spin rotation ($\mu$SR) spectra in the vortex state of type-II superconductors using different theoretical models is presented. Analytical approximations of the London and Ginzburg-Landau (GL) models, as well as an exact solution of the GL model were used. The limits of the validity of these models and the reliability to extract parameters such as the magnetic penetration depth $\lambda$ and the coherence length $\xi$ from the experimental $\mu$SR spectra were investigated. The analysis of the simulated $\mu$SR spectra showed that at high magnetic fields there is a strong correlation between obtained $\lambda$ and $\xi$ for any value of the Ginzburg-Landau parameter $\kappa = \lambda/\xi$. The smaller the applied magnetic field is, the smaller is the possibility to find the correct value of $\xi$. A simultaneous determination of $\lambda$ and $\xi$ without any restrictions is very problematic, independent of the model used to describe the vortex state. It was found that for extreme type-II superconductors and low magnetic fields, the fitted value of $\lambda$ is practically independent of $\xi$. The second-moment method frequently used to analyze $\mu$SR spectra by means of a multi-component Gaussian fit, generally yields reliable values of $\lambda$ in the whole range of applied fields $ H_{c1} \ll H \lesssim H_{c2}$ ($H_{c1}$ and $H_{c2}$ are the first and second critical fields, respectively). These results are also relevant for the interpretation of small-angle neutron scattering (SANS) experiments of the vortex state in type-II superconductors.
Vortex excitations above T_c as revealed by ESR
Yu. Talanov,L. Salakhutdinov,E. Giannini,R. Khasanov
Physics , 2010,
Abstract: Using electron spin resonance (ESR) technique we have obtained data evidencing the existence of magnetic vortices in high-temperature superconductors at temperatures above the critical one $T_c$. We have studied magnetic excitations in \bis single crystals above $T_c$ with the method of surface spin decoration. The surface layer of diphenyl-picrylhydrazyl was used as a sensitive probe of magnetic field distortions. The temperature dependence of the ESR signal parameters has indicated that far above $T_c$ the magnetic flux of a sample is affected by the superconducting order parameter fluctuations while close to $T_c$ its changes are due to vortex-type excitations.
Relevance of electron-lattice coupling in cuprates superconductors
T. Schneider,R. Khasanov,K. Conder,H. Keller
Physics , 2003, DOI: 10.1088/0953-8984/15/50/L03
Abstract: We study the oxygen isotope (^{16}O,^{18}O) and finite size effects in Y_{1-x}Pr_{x}Ba_{2}Cu_{3}O_{7-\delta} by in-plane penetration depth (\lambda _{ab}) measurements. A significant change of the length L_{c} of the superconducting domains along the c-axis and \lambda_{ab}^{2} is deduced, yielding the relative isotope shift \Delta L_{c}/L_{c}\approx \Delta \lambda _{ab}^{2}/\lambda_{ab}^{2}\approx -0.14 for x=0, 0.2 and 0.3. This uncovers the existence and relevance of the coupling between the superfluid, lattice distortions and anharmonic phonons which involve the oxygen lattice degrees of freedom.
Intrinsic and structural isotope effects in Fe-based superconductors
R. Khasanov,M. Bendele,A. Bussmann-Holder,H. Keller
Physics , 2010, DOI: 10.1103/PhysRevB.82.212505
Abstract: The currently available results of the isotope effect on the superconducting transition temperature T_c in Fe-based high-temperature superconductors (HTS) are highly controversial. The values of the Fe isotope effect (Fe-IE) exponent \alpha_Fe for various families of Fe-based HTS were found to be as well positive, as negative, or even be exceedingly larger than the BCS value \alpha_BCS=0.5. Here we demonstrate that the Fe isotope substitution causes small structural modifications which, in turn, affect T_c. Upon correcting the isotope effect exponent for these structural effects, an almost unique value of \alpha~0.35-0.4 is observed for at least three different families of Fe-based HTS.
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