Correlation of transverse relaxation time with structure of biological tissue.

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.

Anisotropy of spin-spin and spin-lattice relaxation times in liquids entrapped in nanocavities: Application to MRI study of biological systems.

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.

Nuclear spin-lattice relaxation in nanofluids with paramagnetic impurities.

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.

NMR method for amplification of single-spin state.

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.