The Experts below are selected from a list of 231 Experts worldwide ranked by ideXlab platform
Hiroshi Kontani - One of the best experts on this subject based on the ideXlab platform.
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intrinsic spin and orbital hall effects in heavy fermion systems
Physical Review B, 2010Co-Authors: T Tanaka, Hiroshi KontaniAbstract:We study the intrinsic spin Hall effect (SHE) based on the orbitally degenerate periodic Anderson model, which is an effective model for heavy fermion systems. In the very low resistivity regime, the magnitude of the intrinsic spin Hall conductivity (SHC) is estimated as $2000\ensuremath{\sim}3000\ensuremath{\hbar}\text{ }{e}^{\ensuremath{-}1}\text{ }{\ensuremath{\Omega}}^{\ensuremath{-}1}\text{ }{\text{cm}}^{\ensuremath{-}1}$; it is about ten times larger than that in Pt. Its sign is negative (positive) in Ce (Yb) compound systems with ${f}^{1}$ $({f}^{13})$ configuration. Interestingly, the Obtained Expression for the SHC depends only on the density of conduction electrons but is independent of the strength of the $c\text{\ensuremath{-}}f$ mixing potential and the mass-enhancement factor. The origin of the huge SHE is the spin-dependent Berry phase induced by the complex $f$-orbital wave function, which we call the ``orbital Aharonov-Bohm effect.''
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general formula for the thermoelectric transport phenomena based on fermi liquid theory thermoelectric power nernst coefficient and thermal conductivity
Physical Review B, 2003Co-Authors: Hiroshi KontaniAbstract:On the basis of linear response transport theory, the general Expressions for the thermoelectric transport coefficients, such as thermoelectric power $(S),$ Nernst coefficient $(\ensuremath{\nu}),$ and thermal conductivity $(\ensuremath{\kappa}),$ are derived by using Fermi liquid theory. The Obtained Expression is exact for the most singular term in terms of $1/{\ensuremath{\gamma}}_{\mathbf{k}}^{*}$ $({\ensuremath{\gamma}}_{\mathbf{k}}^{*}$ being the quasiparticle damping rate). We utilize Ward identities for the heat velocity which is derived by the local energy conservation law. The derived Expressions enable us to calculate various thermoelectric transport coefficients in a systematic way, within the framework of the conserving approximation of Baym and Kadanoff. Thus the present Expressions are very useful for studying strongly correlated electrons such as high-${T}_{c}$ superconductors, organic metals, and heavy fermion systems, where the current vertex correction (VC) is expected to play important roles. By using the derived Expression, we calculate the thermal conductivity $\ensuremath{\kappa}$ in a free-dispersion model up to second order with respect to the on-site Coulomb potential U. We find that it is slightly enhanced due to the VC for the heat current, although the VC for electron current makes the conductivity $(\ensuremath{\sigma})$ of this system diverge, reflecting the absence of the umklapp process.
Hiroyuki Ohshima - One of the best experts on this subject based on the ideXlab platform.
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Approximate analytic Expression for the pH-dependent electrophoretic mobility of soft particles
Colloid and Polymer Science, 2016Co-Authors: Hiroyuki OhshimaAbstract:A theory on the electrophoretic mobility of a soft particle, i.e., a hard particle covered with an ion-penetrable surface layer of polyelectrolytes (Ohshima J Colloid Interface Sci 163: 474, 1994) is extended by taking into account the degree of dissociation of fixed ionizable groups in the polyelectrolyte surface layer. A simple approximate analytic Expression for the pH-dependent electrophoretic mobility of a soft particle, carrying monovalent acidic ionizable groups in the polyelectrolyte layer, is derived, which involves the pH-dependent Donnan and surface potentials of a soft particle. With the help of the Obtained Expression for the pH-dependent electrophoretic mobility of soft particles, the electrophoretic fingerprinting approach can be applied to soft particles.
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electrophoretic mobility of a highly charged soft particle relaxation effect
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2011Co-Authors: Hiroyuki OhshimaAbstract:Abstract An approximate analytic Expression is derived for the electrophoretic mobility of a soft particle, that is, a hard particle of radius a covered with an ion-penetrable surface layer of polyelectrolytes of thickness d in an electrolyte solution of concentration n under conditions at which κa ≫ 1, κd ≫ 1, λa ≫ 1, and λd ≫ 1 (where κ = Debye–Huckel parameter and 1/ λ = softness parameter). The Obtained Expression is an improvement of a previously derived mobility Expression [Ohshima, J. Colloid Interface Sci., 163 (1994) 474; ibid. 228 (2000) 190] by taking into account the relaxation effect for the region outside the surface charge layer so that it can be applicable for arbitrary values of the density N of fixed-charges in the surface charge layer. It is observed that the electrophoretic mobility plotted as a function of N or n exhibits a maximum due to the relaxation effect.
Adrián Rocha-ichante - One of the best experts on this subject based on the ideXlab platform.
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Second virial coefficient of a generalized Lennard-Jones potential.
The Journal of chemical physics, 2015Co-Authors: Alfredo González-calderón, Adrián Rocha-ichanteAbstract:We present an exact analytical solution for the second virial coefficient of a generalized Lennard-Jones type of pair potential model. The potential can be reduced to the Lennard-Jones, hard-sphere, and sticky hard-sphere models by tuning the potential parameters corresponding to the width and depth of the well. Thus, the second virial solution can also regain the aforementioned cases. Moreover, the Obtained Expression strongly resembles the one corresponding to the Kihara potential. In fact, the Fk functions are the same. Furthermore, for these functions, the complete expansions at low and high temperature are given. Additionally, we propose an alternative stickiness parameter based on the Obtained second virial coefficient.
Andrea Pelissetto - One of the best experts on this subject based on the ideXlab platform.
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Virial coefficients and osmotic pressure in polymer solutions in good-solvent conditions
The Journal of chemical physics, 2006Co-Authors: Sergio Caracciolo, Bortolo Matteo Mognetti, Andrea PelissettoAbstract:We determine the second, third, and fourth virial coefficients appearing in the density expansion of the osmotic pressure of a monodisperse polymer solution in good-solvent conditions. Using the expected large-concentration behavior, we extrapolate the low-density expansion outside the dilute regime, obtaining the osmotic pressure for any concentration in the semidilute region. Comparison with field-theoretical predictions and experimental data shows that the Obtained Expression is quite accurate. The error is approximately 1-2% below the overlap concentration and rises at most to 5-10% in the limit of very large polymer concentrations.
A Afbnas - One of the best experts on this subject based on the ideXlab platform.
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to the theor17 of spherical particles localization in the field of zeroth order bessel beam the rayleigh gans approximation
2003Co-Authors: A A Rjibinov, A AfbnasAbstract:In this paper the amplitude of gradient force acting on a transparent spherical particle in the field of the zeroth order Bessel beam is calculated. The Obtained Expression for gradient force amplitude, takes into account heterogeneity of acting radiation in the volume of particle. Optimal conditions (parameters of particle, liquid, and Bessel beam) for localization and transportation of a particle are determined using the solution of kineticequation. It was shown, that for some definite relationships between the particle size and the width of Bessel beam the localization region is shifted from the central maximum of the beam. It is cause by the equilibrium the gradient forces from the central maximum and from first interference ring of the Bessel beam. The qualitative comparison of the Obtained results with known experimental data is performed.
