The nonlinear dielectric relaxation ac stationary response of an assembly rigid polar molecules acted on by strong superimposed external dc E0 and E1(t)=E(1) cos omegat electric fields is evaluated in the context noninertial rotational diffusion model. calculation proceeds expanding functions f(n)(t) (the expectation value Legendre polynomials P(n)), which describe system, as a Fourier series time domain. Hence, infinite hierarchy recurrence equations for components obtained. exact solution...

Les limites de la phase L2 des diagrammes ternaires AOT- eau-n-heptane et AOT-eau-n-décane sont définies à température 20 °C.

The dielectric relaxation spectroscopy is used for studying the orientational molecular dynamics in isotropic (I) and nematic (N) phases of two mesogenic liquids composed molecules similar structure length, but an essentially different polarity: n-heptylcyanobiphenyl, C(7)H(15)PhPhCN, 7CB (molecular dipole moment mu approximately 5D) 4-(trans-4'-n-hexylcyclohexyl)isothiocyanatobenzene, C(6)H(13)CyHxPhNCS, 6CHBT (mu 2.5D); advantageously, temperatures I-N phase transition compounds are very...

Based on the temperature behavior of entropy increment induced by probing electric field in isotropic phase mesogenic compounds belonging to homologous series C(n)H(2n+1)PhCOOPhCN ( n = 4-10), it is found that an ability dipolar aggregation molecules depends alkyl tail length, and, particular, strongly reinforced when number changes from 7 8. The role molecular structure self-assembling process discussed.

The problem of the nonlinear dielectric response due to application a strong electric field is reconsidered in context fractional kinetic equations. To accomplish that, we start from noninertial Fokker-Planck equation and restrict ourselves case anomalous subdiffusive processes characterized by critical exponent alpha ranging 0 1, limit normal diffusion. In particular, evaluate first- third-order harmonic components polarization either pure ac or dc bias superimposed on weak field....

The infinite hierarchy of differential-recurrence relations for ensemble averages the spherical harmonics pertaining to noninertial rotational Brownian motion an polar and anisotropically polarizable molecules in a strong external dc electric field is derived by averaging underlying Langevin equation. This procedure avoids recourse Fokker-Planck equation, solution which involves complicated mathematical manipulations. Exact analytic solutions spectra relaxation functions times nonlinear...

Dielectric relaxation measurements are performed with very high accuracy on a liquid crystalline compound n-octylcyanobiphenyl (8CB) in the isotropic (I), nematic (N) and smectic A (SA) phases. The data obtained display an essential difference rotational diffusion process vicinity of I–N phase transition comparison to that taking place N–SA transition. Thus, for transition, anomalously slow (subdiffusion), characterized by anomalous coefficient α<1, is observed, while normal Brownian found...

The linear and nonlinear dielectric relaxation spectra, recorded in the isotropic phase of mesogenic 4-(trans-4'-n-hexylcyclohexyl)isothiocyanatobenzene (6CHBT), reveal an equilibrium between molecules that are involved non-involved pseudo-nematic domains, which spontaneously formed prenematic region. A perturbation by a static electric field high strength (E0 approximately 10(7) V/m) is followed process that, measured with probing E(omega) small amplitude variable frequency (up to 100 MHz),...

We investigate the thermal generation and transport properties of an assembly magnetic nanoparticles embedded in a solid or fluid matrix, subjected to AC field. For this purpose, we first build heat equation for using effective coefficients obtained within medium approach. In present calculation, SAR is from (linear) dynamic response numerically solve extended and, as preliminary study, obtain space-time profile temperature total power absorbed by system.

The nonlinear response to a step external force of system with relaxational dynamics governed by one-dimensional Fokker-Planck equation is considered. An exact analytical expression for the relaxation time derived in terms an integral (which can be evaluated numerically). Applications problems concerning dynamic Kerr effect, dielectric liquid dielectrics, and magnetic systems single domain ferromagnetic particles are given. results compared solutions previously obtained.

The nonlinear impedance of a point Josephson junction is calculated under various conditions for the resistively shunted model in presence noise. calculation proceeds by solving Langevin equation mechanical problem Brownian particle tilted cosine potential strong ac force ignoring inertial effects. exact solution infinite hierarchy equations moments (expectation values Fourier components phase angle), which describe dynamics junction, expressed terms matrix continued fraction. This allows...

Both nonlinear dielectric relaxation and dynamic Kerr effect responses of an assembly polar anisotropically polarizable molecules acted on by strong superimposed external dc E0 ac E1(t)=E1 cos ωt electric fields are evaluated in the context rotational diffusion model noninertial limit. The functions fn(t) (the expectation value Legendre polynomials Pn), which appropriate to describe these phenomena, calculated expanding them as a Fourier series time domain. An infinite hierarchy recurrence...

A new interpretation of the pretransitional temperature behavior static dielectric permittivity and its derivative in terms basic thermodynamic quantities: internal energy, entropy, Helmholtz free energy is presented.It was shown that case strongly polar mesogenic compounds (as homologous series alkylcyanobiphenyls) electric field-induced increments both entropy exhibit a critical-like dependence vicinity transition from isotropic liquid to nematic phase.As most important effect, it at about...

We address the issue of inter-particle dipolar interactions in context magnetic hyperthermia. More precisely, main question dealt with here is concerned conditions under which specific absorption rate enhanced or reduced by interactions. For this purpose, we propose a theory for calculation AC susceptibility, and thereby rate, monodisperse two-dimensional assembly nanoparticles oriented anisotropy, presence DC field, addition to field. also study competition between both transverse...

Dielectric relaxation of complex polar fluids is considered in the context anomalous diffusion characterized by a fractional parameter alpha < or = 1 (subdiffusion). An infinite hierarchy three-term differential-recurrence equations governing time evolution electric polarization established following purely phenomenological procedure. The matrix-continued fraction method used to derive exact numerical solution stationary regime for an assembly nonelectrically interacting, symmetric-top...

The p K a of eighteen heterocyclic carboxylic acids derived from thiophene, furan, pyrrole, benzothiophene, benzofuran, indole, pyridine and quinoline have been determined by spectrophotometry potentiometry. values thus obtained are discussed using additive models the Free-Wilson type. Some theoretical calculations within AM1 approximation carried out in order to understand why annelation effects dependent on position, α or β, group. In case acids, problem tautomerism between neutral...

Perturbation theory is used to derive the complex harmonic components (stationary regime) arising in Kerr effect relaxation for an assembly of nonelectrically interacting, polar, and polarizable symmetric-top molecules acted on by a strong dc bias electric field superimposed weak ac field. The approach starts from fractional kinetic equation written configuration space represents extension Smoluchowski dynamics. This solved context subdiffusive process characterized anomalous exponent alpha...

We develop a general formalism for analyzing the ferromagnetic resonance characteristics of magnetic dimer consisting two elements (in horizontal or vertical configuration) coupled by dipolar interaction, taking account their finite-size and aspect ratio. study effect on frequency field applied amplitude direction), inter-element coupling, uniaxial anisotropy in various configurations. obtain analytical expressions regimes interlayer coupling. (numerically) investigate behavior corresponding...

The solution of the Langevin equation describing dynamics a Brownian particle in tilted periodic potential overdamped limit is obtained terms matrix continued fraction, allowing us to evaluate statistical averages governing nonlinear response strong ac force. Pronounced effects are observed for large values For weak force and low noise strength, results agree closely with previously available linear noiseless solutions, respectively.

The steady-state nonlinear dielectric response is calculated where the applied electric field consists of an alternating superimposed on a constant field. Both permanent and induced dipolar moments are considered. This gives rise to three harmonic terms in ω, 2ω, 3ω which time-dependent stationary frequency-dependent term, if we restrict ourselves third-order response. These results obtained from Smoluchowski equation by using perturbation method therefore complementary those previously...

Magnetic relaxation in Ni nanowires was measured both on single and an array of about 106 nanowires. The logarithmic rate S = dM/d ln(t) deduced from after-effect experiments is presented as a function the applied field temperature. dependence S(H) very similar to distribution switching fields array, whereas time one nanowire linear window experiment. temperature S(T) arrays decreases with increasing measurement macroscopic used infer thermal behavior This conflict Néel-Brown activation...

In the case of a nonlinear stationary response resulting from application an alternating field superimposed on continuous in dielectric liquid, birefringence that medium is well expressed as real and imaginary parts two normalized complex functions \ensuremath{\Delta}${N}_{j}^{\mathrm{*}}$=${X}_{j}$-${\mathrm{iY}}_{j}$, where j=1,2. By eliminating angular frequency \ensuremath{\omega} parametric equations ${X}_{j}$(\ensuremath{\omega}) ${Y}_{j}$(\ensuremath{\omega}), Cartesian are obtained,...

The problem of the nonlinear dielectric relaxation complex liquids is tackled in context Cole-Davidson [J. Chem. Phys. 19, 1484 (1951)] model. By using an appropriate time derivative noninteger order, infinite hierarchy differential-recurrence relations for moments (expectation values Legendre polynomials) obtained. solution established stationary regime ensemble polar and symmetric-top molecules acted on by a strong dc bias electric field superimposed weak ac field. results first three...