Papers by Victor Meerovich
International Journal of Applied …, 2001
... high-temperature superconductors V. Meerovich a,∗ , V. Sokolovsky a and I. Vajda b a Ben-Guri... more ... high-temperature superconductors V. Meerovich a,∗ , V. Sokolovsky a and I. Vajda b a Ben-Gurion University of the Negev, POBox 653, 84105 Beer-Sheva, Israel b Budapest University of Technology and Economics, Egry Jozsef utca 18, H-1111, Budapest, Hungary Abstract. ...
Journal of Magnetic Resonance
Journal of Magnetic Resonance
Journal of Magnetic Resonance
Physica C: Superconductivity, 2000
Due to the very low thermal conductivity of high temperature superconductors HTSC , AC losses can... more Due to the very low thermal conductivity of high temperature superconductors HTSC , AC losses can result in a non-uniform temperature distribution inside a sample. We report the results of an experimental investigation of the temperature distribution in the wall of the BSCCO hollow cylinder in AC magnetic field. The BSCCO cylinder has a 2 Ž. relatively low critical current density of 550 Arcm at 77 K measured under DC conditions at 1 mVrcm criterion. The Ž temperature of the interior of the cylinder relative to the outside coolant raised 2.5 K at low external magnetic field ; 0.04. T. The change in temperature is increased linearly with frequency and as the third power of the applied magnetic field. The experimental results are compared with the theoretical predictions obtained in the framework of the critical state model complemented by the heat equation.
Journal of magnetic resonance (San Diego, Calif. : 1997), Sep 1, 2016
Transverse spin-spin relaxation of liquids entrapped in nanocavities with different orientational... more Transverse spin-spin relaxation of liquids entrapped in nanocavities with different orientational order is theoretically investigated. Based on the bivariate normal distribution of nanocavities directions, we have calculated the anisotropy of the transverse relaxation time for biological systems, such as collagenous tissues, articular cartilage, and tendon. In the framework of the considered model, the dipole-dipole interaction is determined by a single coupling constant. The calculation results for the transverse relaxation time explain the angular dependence observed in MRI experiments with biological objects. The good agreement with the experimental data is obtained by adjustment of only one parameter which characterizes the disorder in fiber orientations. The relaxation time is correlated with the degree of ordering in biological tissues. Thus, microstructure of the tissues can be revealed from the measurement of relaxation time anisotropy. The clinical significance of the corre...
Quantum Information Processing, 2014
ABSTRACT We study behavior of quantum discord, a kind of quantum correlation, in systems of dipol... more ABSTRACT We study behavior of quantum discord, a kind of quantum correlation, in systems of dipole-dipole interacting spins in an external magnetic field in the whole temperature range (). It was shown that negative temperatures, which are introduced to describe inversions in the population in a finite level system, provide more favorable conditions for emergence of quantum correlations including entanglement. We show that at negative temperature, the correlations become more intense and discord exists between remote spins being in separated states.
Journal of magnetic resonance (San Diego, Calif. : 1997), 2015
We study the spin-lattice relaxation of the nuclear spins in a liquid or a gas entrapped in nanos... more We study the spin-lattice relaxation of the nuclear spins in a liquid or a gas entrapped in nanosized ellipsoidal cavities with paramagnetic impurities. Two cases are considered where the major axes of cavities are in orientational order and isotropically disordered. The evolution equation and analytical expression for spin lattice relaxation time are obtained which give the dependence of the relaxation time on the structural parameters of a nanocavity and the characteristics of a gas or a liquid confined in nanocavities. For the case of orientationally ordered cavities, the relaxation process is exponential. When the nanocavities are isotropically disordered, the time dependence of the magnetization is significantly non-exponential. As shown for this case, the relaxation process is characterized by two time constants. The measurements of the relaxation time, along with the information about the cavity size, allow determining the shape and orientation of the nanocavity and concentra...
Journal of magnetic resonance (San Diego, Calif. : 1997), Jan 4, 2016
Spin-spin and spin-lattice relaxations in liquid or gas entrapped in nanosized ellipsoidal caviti... more Spin-spin and spin-lattice relaxations in liquid or gas entrapped in nanosized ellipsoidal cavities with different orientation ordering are theoretically investigated. The model is flexible in order to be applied to explain experimental results in cavities with various forms, from very prolate up to oblate ones, and different degree of ordering of nanocavities. In the framework of the considered model, the dipole-dipole interaction is determined by a single coupling constant, which depends on the form, size, and orientation of the cavity and number of nuclear spins in the cavity. It was shown that the transverse and longitudinal relaxation rates differently depend on the angle between the external magnetic field and cavity main axis. The calculation results for the local dipolar field, transverse and longitudinal relaxation times explain the angular dependencies observed in MRI experiments with biological objects: cartilage and tendon. Microstructure of these tissues can be characte...
27th European Microwave Conference and Exhibition, 1997
ABSTRACT Not Available
Physica C: Superconductivity, 1993
The model of an inductive current-limiting device consists of a copper coil and a high-Tc superco... more The model of an inductive current-limiting device consists of a copper coil and a high-Tc superconducting ring which are placed on a ferrite core and are coupled magnetically. The rings were prepared by extrusion of the YBaCuO submicron precursor powder and organic binder, followed by sintering in oxygen atmosphere. The principle of the device's operation is based on a rapid
Applied Superconductivity, 1994
The experimental investigation results of superconducting-normal state transitions in a high-T, s... more The experimental investigation results of superconducting-normal state transitions in a high-T, superconducting ring with induced current are presented. A transformer device is used, where the superconducting ring forms a secondary winding of a transformer. Using the analysis method based on an equivalent circuit of the transformer, the voltage and current in the ring vs time are obtained from oscilloscope traces of the voltage and current in the primary winding of the device. The dynamic voltage-current characteristic of the ring is found to have a hysteresis. This hysteresis is explained by the inertia of thermal processes and propagation of a resistive zone in the ring.
Materials Science Forum, 2012
The results of experimental study of the critical current and AC losses in high pressure-synthesi... more The results of experimental study of the critical current and AC losses in high pressure-synthesized MgB2bulk superconductors are presented. The method is based on the use of the transformer configuration and suitable for samples in the form of hollow superconducting cylinders and rings. It was shown that the critical current measured by the transformer method is an order of magnitude lower than the value given by the magnetization technique. The obtained dependencies of the losses on current and frequency reveal the deviations from the critical state model behavior and reflect structural peculiarities of the investigated MgB2samples.
RSC Adv., 2015
The multiple pulse spin locking dynamics of the nuclear spins in nanofluids was studied. Oriented... more The multiple pulse spin locking dynamics of the nuclear spins in nanofluids was studied. Oriented (a) and disoriented (b) nanocavities containing water molecules (c) were considered. Analytical expressions for the magnetization and the relaxation time were obtained.
Solid state nuclear magnetic resonance
We investigate theoretically the Multiple Quantum (MQ) NMR dynamics at negative absolute temperat... more We investigate theoretically the Multiple Quantum (MQ) NMR dynamics at negative absolute temperatures in systems of nuclear spins 1/2 coupled by the dipole-dipole interactions and with the initial conditions determined by the dipolar ordered state. Two different methods of MQ NMR are used. One of them is based on the measurement of the dipolar energy. The other method uses an additional resonance (π/4)y-pulse after the preparation period of the standard MQ NMR experiment. It is shown that at negative temperatures many-spin clusters and spin correlations are created faster, and the intensities of MQ coherences are higher than in the usual MQ NMR experiments. So, the eighth-order MQ coherence in 10-spin system of the cyclopentane molecule appears to be 1.5 times faster and its intensity is four orders higher than at positive temperatures. The proposed MQ NMR methods at negative absolute temperatures can be used for the investigation of many-spin dynamics of nuclear spins in solids.
Solid state nuclear magnetic resonance, 2007
Amplification of a single-spin state using nuclear magnetic resonance (NMR) techniques in a rotat... more Amplification of a single-spin state using nuclear magnetic resonance (NMR) techniques in a rotating frame is considered. The main aim is to investigate the efficiency of various schemes for quantum detection. Results of numerical simulation of the time dependence of individual and total nuclear polarizations for 1D, 2D, and 3D configurations of the spin systems are presented.
Zeitschrift für Naturforschung A, 2007
The process of amplification of a single spin state using nuclear magnetic resonance (NMR) techni... more The process of amplification of a single spin state using nuclear magnetic resonance (NMR) techniques in a rotating frame is considered. Our main aim is to investigate the efficiency of various schemes for quantum detection. Results of numerical simulation of the time dependence of individual and total nuclear polarizations for 1D, 2D, and 3D configurations of the spin systems are presented.
Uploads
Papers by Victor Meerovich