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The aim of this paper is to study the free vibration problem of a thermoelastic hollow cylinder in the context of the Lord and Shulman theory with one relaxation time. The eigenvalue approach is used to get the analytical solutions. The dispersion relations for the existence of various types of possible modes of vibrations are obtained. The validation of the roots for the dispersion relation is presented. The numerical results of frequency shift, natural frequency, and thermoelastic damping of vibrations have been presented graphically. PACS No.: 62.20.Dc. Nous etudions ici les vibrations libres d'un cylindre creux fait d'un materiau thermoelastique, en utilisant la theorie de Lord et Shulman avec un seul temps de relaxation. Nous utilisons une approche aux valeurs propres afin de trouver des solutions analytiques et obtenons les relations de dispersion pour les differents modes possibles de vibration. Nous validons les racines de ces relations de dispersion. Nous presentons graphiquement le deplacement en frequence, la frequence naturelle et l'amortissement thermoelastique des vibrations. [Traduit par la Redaction], 1. Introduction The linear theory of elasticity is of paramount importance in the stress analysis of steel, which is the most common engineering structural material. To a lesser extent, linear [...]

The possibility of V-pit formation at terminated dislocations as the predominant relaxation mechanism in highly mismatched systems such as In(sub x)Ga(sub 1-x)N/GaN is explored. The findings suggest that V-pit formation and growth lead to strain relief as the film becomes thicker.

The in situ stress measurements during molecular-beam epitaxy growth of In(sub x)Ga(sub 1-x)As/GaAs provide insight into the relaxation behavior of thin films grown on mismatched substrates. The effect of a nonunifom dislocation array configuration on the overall relaxation behavior is discussed and the results from dislocation dynamics simulations are presented.

A cap layer was used to suppress buckling during the relaxation of compressively strained 30 nm Si0.7Ge0.3 islands on borophosphorosilicate glass. Large, fully relaxed, smooth SiGe islands obtained using cap layers indicate that this approach could be of potential use for electronic device applications.

Measurements of the strain relaxation process in KD2PO4 is discussed. It indicates that the strain waves are generated in the corners of the samples, from where the waves propagate inward at an angle of 45 degree, in square samples the strain waves propagate along the diagonals of the plate.

Phosphorus diffusion has been studied in relaxed Si(sub 1-x)Ge(sub x) samples (x=0.11 and 0.19) and strained Si/Si(sub 1-x)Ge(sub x)/Si heterostrucutres(x=0.08,0.13, and 0.18). Further, P is found to segregate into Si across Si/Si(sub 1-x)Ge(sub x) interfaces and the segregation coefficient increases with increasing Ge concentration.

The electron temperature method is developed for high-density two-dimensional electron gas (2DEG). The method works in the field range up to 3 kV/cm in the consideration 2DEG channels.

The influence of He implantation and annealing on the relaxation of Si(sub 0.7)Ge(sub 0.3) layers on Si (100) substrates is investigated. A low threading dislocation density of 10(super 7) cm(super -2) is achieved.

We present an analysis of the relaxation oscillations in a laser with a Gaussian mirror by taking into account the three-dimensional spatial field distribution of the laser modes and the spatial hole burning effect. In particular, we discuss the influence of the Gaussian mirror peak reflectivity and a Gaussian parameter on the damping rate and frequency of the relaxation oscillation for two different laser structures, i.e., with a classically unstable resonator and a classically stable resonator. OCIS codes: 140.0140, 140.3410, 140.3430, 140.3460.

The detailed comparison of the experimental decomposition of a thermally stimulated depolarization current (TSDC) global relaxation by using thermal sampling (TS) technique and the numerical decomposition obtained with the direct signal analysis (DSA) procedure shows that the results agree when using Arrhenium relaxation times, in spite of the unreal values for the relaxation parameters given by both methods. The partial discharge of the low temperature tail performed on the global peak when fitting it with VTF Debye peaks also helps in minimizing the aging effects which could seriously effect the TS experiments.

Investigation is carried out on the effect of polymeric coatings on the static fatigue. The applied tensile force is gradually transferred from the polymeric coating to the glass fiber and the tensile stress in the glass increases with time due to the viscoelastic behavior of the polymeric coating and the relaxation of the secondary coating should be increased to decelerate this increase resulting in higher stress amplification factor.

By using a bilayer serial model, the study has shown that heterogeneous piezoelectric structures may exhibit Maxwell-Wagner type piezoelectric relaxation if the constitutent materials possess different dielectric and piezoelectric properties. The model is relevant for a wide range of heterogeneous structures.

The radio frequency (rf) dynamical characteristics of a very strongly hysteretic superconducting quantum interference device (SQUID) ring, coupled to an rf tack circuit resonator display relaxation oscillations. It is demonstrated that the overall form of these characteristics, together with the relaxation oscillations can be modeled accurately by solving the quasiclassical nonlinear equations of motion for the system.

The thermalization of nonequilibrium electrons and phonons is investigated theoretically by using a semiclassical description of the Boltzmann equations. By utilizing a discretization scheme, the coupled nonlinear Boltzmann equations for the electron-phonon system are directly solved numerically.

The short time relaxation effects in amorphous ferromagnetic ribbons of Fe64Co21B15 and Co77B23 are investigated using three-dimensional neutron depolarization and magnetic induction method. Results show that the time dependence of magnetization caused by the stabilization of the domain wall to an equilibrium position is dependent on the sample composition and stress anisotropy. A model was also derived to analyze the experimental findings.

Characteristic peculiarities of the formation of the photoacoustic-detector signal from excitation of absorbing gas molecules by a short laser pulse ([[Tau].sub.p] [much less than] [[Tau].sub.vt]) that allows for the natural oscillations of the microphone membrane are considered. A technique for [[Tau].sub.vt] measurement is proposed on the strength of the finding that the signal form is determined by the microphone membrane oscillation under low pressure (P [less than or equal to] 10 Torr). The results of measurement of the [[Tau].sub.vt] of the vibrational state [v.sub.1] + 3[v.sub.3] in [H.sub.2]O for the collisions [H.sub.2]O-[H.sub.2]O and [H.sub.2]O-air are presented.

Experimental methods help determine the stability of the electro-optic coefficient of a cross-linked and poled nonlinear optical polymer at 100, 85 and 110 degrees Celsius. Various models help analyze the orientational relaxation of the optical dyes. The continuously varying relaxation time is responsible for the orientational relaxation in the polymers.

Examination of various models of slow relaxation in magnetic materials indicates that a theory based on intrinsic energy accounts for the form of time dependence of magnetization. A fictitious fluctuation field Hf that helps evaluate the activation volume Vact helps relate the slow relaxation to irreversible magnetic behavior. Magnetization reversal process exhibits relation with both Hf and Vact, and a comparative study of the Monte Carlo simulations with experimental data confirms the relation of Vact with micromagnetic magnetization reversal mode.

A model suggests interactions or couplings as the origin for the quasilogarithmic time dependence associated with many physical systems. Interactions of the dipole-dipole couplings and relaxing spins drive the system from its initial state to equilibrium, and relaxation of the system decreases both dipolar energy and driving force. The relaxation leads to slow relaxation-time dependence. The model accounts for the nonmonotonic temperature dependence of the logarithmic decay slope.

Examination of the optical characteristics of an AlInAs/InP type-II superlattice at room temperature reveals that excitons in type-II superlattice are responsible for the occurrence of peak structures in the photocurrent spectra. Electroabsorption studies prove that application of the electric field increases the excitonic structure. The relaxation time of type-II superlattices measured by time-resolved photoluminescences is almost similar to that of type-I superlattices.

Femtosecond optical studies of minority electrons present in carbon-doped GaAs reveal that fast electron-hole scattering enhances the minority electron relaxation to low-energy states. Reflectivity and transient absorption depend on the high hole concentration that causes an energy-loss in the doped material. Band tailing and band-gap renormalization provide the low-energy states for electron relaxation.

A new approach was used to elucidate the relaxation in Si/SiGe bilayers grown on Si/SiO2 substrates. The bilayer was relaxed when the Si layer was subjected to glide dislocation and the top SiGe layer was relaxed and remained free from dislocation. Maximum relaxation was obtained when the temperature was above 1050 degrees centigrade.

Nanosecond laser pulses were used to analyze crystallization and relaxation kinetics of amorphous germanium films on silicon. The thermal conductivity of the silicon substrate efficiently extracted the film-absorbed laser energy to facilitate amorphous regrowth of the films when subjected to melting and sudden solidifications.

A differential scanning calorimetry is used to investigate the effects of relaxation on the glass transition and crystallization of Zr(sub 41)Ti(sub 14)Cu(sub 12.5)Ni(sub 10)Be(sub 22.5) bulk metallic glass. Results show that glass transition and crystallization behavior and their activation energy are marked effectively by the preannealing induced relaxation.

Analysis of lattice relaxation in Al(x)Ga(1-x)As layers grown on GaAs(100) substrate plane by organometallic vapor phase epitaxy shows that the coherent length of AlGaAs is susceptible to reduction induced by tensile stress rather than compressive stress. Coherent length also depends on growth temperature. Infusion of even small amount of Al in the epilayers on GaAs substrates increases the coherent length.

A crossover in the presence of reentrant transition was observed when low-field thermoremanent relaxation in a reentrant was measurement. The crossover involved the reentrant's transition from equilibrium dynamics in the ferromagnetic phase to nonequilibrium dynamics. The transition was age-dependent in the reentrant phase.

The article explains the various effects of long-range screening exhibited on the surface morphology of the thin films that are formed by the magnetron sputtering deposition technique. The transition taking place in the films is shown to be highly dependent on the diffusional relaxation and angular distribution of the incident particle flux.

The various mechanisms involved in the strain relaxation taking place in the highly mismatched hexagonal heterosystem are analyzed. The formation of the various interfacial misfit dislocations during the relaxation process is also studied.

Relaxation oscillations in chalcogenide phase change memory are studied and voltage and current oscillations are measured. The physical mechanism of oscillations and their stochastic nature are described in the framework of field-induced nucleation, while the transition from stable to decaying amplitudes is ascribed to concomitant thermally induced nucleation.

The new semiconducting noncrystalline solid tellurite glasses are prepared in bulk form with different compositions. The results have showed the presence of a very well defined peak that has shifted to higher temperature with increasing frequency, which has shown a kind of relaxation process.

Epitaxial ferroelectric Pb[Zr.sub.0.2][Ti.sub.0.8][O.sub.3] thin films are grown by pulsed laser deposition and they are doped with Cr acting as acceptor ion. The Cr has facilitated the elastic relaxation of the film and the leakage current is increased through a reduction of the Schottky barrier.

In situ measurements are performed on the high-frequency shear modulus during linear heating into the glass transition region of bulk glassy [Pd.sub.40][Cu.sub.30][Ni.sub.10][P.sub.20] sample in the initial state, after full structural relaxation, and subsequent fast quenching from the supercooled liquid region. Fast quenching after full relaxation has resulted in the recovery of structural relaxation and the concentration of interstitialcylike defects in the initial, relaxed, quenched conditions is calculated.

Electron paramagnetic resonance (EPR) signals of both modern and ancient wooden taxa are studied in order to analyze some features of the free radicals in natural wood. Microwave power saturation behaviors of seasoned wooden samples are studied and remarkable differences are found between softwoods and hardwoods.

A well-posed magnetic imaging method based on magnetic relaxation of magnetic nanoparticles is used for obtaining high-spatial resolution image of magnetic tracers. An image of superparamagnetic iron oxide nanoparticles tracer is obtained from mapping the magnetization decays and the imaging capability is shown by using gamma-ferric oxide magnetic nanoparticles.

Spin dynamics of antivortices excited by sudden action of a spin-polarized dc is described. Two main excitation modes have increased current density, which have involved a translational (gyrotropic) mode and a core reversal mode.

A fully coupled finite element method (FEM) is used for analyzing a cooling effect of magnetic fluid with an alternating magnetic field driven with the power frequency of 60 Hz. The Langevin function is used for considering the nonlinear magnetic susceptibility for analyzing the Kelvin force density and the power dissipations due to the Neel relaxation and Brownian relaxation.