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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 [...]

Several experimental studies are conducted to explain the impact of the electrical properties and structural relaxation (SR) of the chalcogenide materials on the phase-change memory (PCM) cells. A high current or high voltage readout is shown to highly improve the resistance stability of the system.

The article presents and examines a new physical model, which is employed to demonstrate the impact of structural relaxation (SR) of the chalcogenide materials on the reliability of phase-change memory (PCM) cells. The defect annihilation dynamics is also shown to be highly affected by the electrical characteristics of the cells.

A micrographic study is performed to determine struts dimensions and cell geometry and hence, a unit cell model to describe these open-cell polymeric foams. The analysis of the measured sigmoid growth is used for determining the probability function, needed by the probabilistic tortuous walk model, which has described the variation of the apparent tortuosity.

A new technique is proposed for the robust estimation of relaxation-time distribution in tissue. Results suggest the feasibility of the proposed technique.

A methodology used to determine unrelaxed mobilities [mu]m of model peptides and proteins including finite bead size effects is outlined and the method used to account icon relaxation is examined. It is learnt that the effects of ion relaxation can be significant if the absolute electrophoretic mobility of a peptide exceeds approximately 0.20 [cm.sup.2]/ (kV s).

The water [2.super.H] and [17.super.O] magnetic relaxation dispersion (MRD) profiles from gelatin gels over wide ranges of resonance frequency and pH are reported. The MRD analysis shows a highly mobile hydration layer at the surface of the gelatin triple helix and a small number of trapped water molecules with residence times on the order of [10.sup.-8]s, presumably associated with structural defects and branch points in the gel.

The excitation relaxation dynamics of dimethylanthracene (DMA) in aqueous solutions in the presence of [alpha]-, [beta]-, and [gamma]-CDs was studied and it was found that there are both hydrated and anhydrated species of DMA in the [alpha]- and [gamma]-CD nanocavities. The structure of anhydrated (DMA)2-([gamma]-CD)2 is configured from the [(sup.1).B.sub.b] exciton splitting observed in the fluorescence excitation spectrum with the help of LJ + Coulombic potential calculations.

The solid state NMR spectroscopy was used for (super 31)P and (super 2)H relaxation studies of helix VI and the cytoplasmic helix of human cannabinoid receptor. This technique can be used to sense the physical state of the lipid bilayer as well as the molecular motions associated with acyl chains in the presence of macromolecules.

A theoretical investigation of the modification of dynamical properties in a semiconductor laser by a strong injected signal is presented. The results show different relaxation oscillation behaviors for free-running and injected lasers, arising from distinctly different physical processes.

The dynamic disorder in the crystalline phases of anhydrous caffeine is studied using the dielectric technique of thermally stimulated depolarization currents (TSDC). The experimental results suggest that both crystalline phases II and I of caffeine, that have distinct crystal structures, are solid rotator phases showing reorientational glass transition at the same temperature in phase II and in metastable phase I.

The high-bias electrical properties of suspended metallic single-walled carbon nanotubes (SWNTs) are investigated at various temperatures in vacuum, in various gases, and when coated with molecular solids. The results reveal that the gas molecules surrounding suspended SWNTs assist the relaxation of hot phonons and afford enhanced current flow along nanotubes.

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 design of an up/down counter composed of 4-Junction Logic (JL) gates and the digital/analog (D/A) converter using an R-2R ladder circuit is presented to realize the digital flux locked-loop (FLL) circuit. The 4 JL gates with the Superconducting QUantum Interference Device (SQUID) regulator is developed and the correct logic operations are successfully confirmed using fabricated 4JL gates.

The relaxation of the O - H stretch vibration of water in aqueous salt solvent using femtosecond bi-color pump-probe spectroscopy is examined. A model explaining all the effects of ions on the vibrational relaxation of liquid water is presented.

Electron spin lattice relaxation rates (1/T1e) of nitroxyl radicals were measured by saturation recovery at X-band, S-band and L-band. Further studies are required to understand the relevant motions of nitroxyls with different structures.

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.

Supercritical CO2 is expected to be an environmentally benign media for reaction processes. The experimental determination or reorientational correlation provides a picture of solvation dynamics of CO2.

The triethylamine (TEA)/water system that provides a classic base model for phase separation in a relatively simple mixture is studied. This mixture has a lower critical consolute temperature and is also convenient for inducing phase-separation.

New NMR relaxation methods are presented that describe ligand flexibility at the atomic level and natural abundance (super 13)C cross-correlated relaxation parameters are measured for ligands in rapid exchange between the free and receptor-bound states. The ligand flexibility profiles obtained from the relaxation data helps to assess the influence of dynamics on ligand potency or pharmacokinetic properties or both.

Low frequency dielectric study of glass-forming maltitol and sorbitol is performed. Side branching leads in maltitol to a sharpening of the corresponding distribution and occurrence of an intermediate strongly activated process, which has no separate secondary counterpart.

A study demonstrating a means to monitor energy flow on the surface of cubic MgO nanoparticles chemically is presented. Bleaching of electron holes by H2 plays a significant role in the assessment of excitation and subsequent relaxation processes related to O(super 2-) anions in MgO surfaces.

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.

Vibrational relaxation, mode coupling, and peptide structural constraints are obtained by femtosecond two-dimensional vibrational spectroscopy of an acetylproline-NH2 model peptide. Three high-frequency vibrational modes are examined, two amide-I modes and the amide-II amino end mode, where efficient vibrational energy transfer between amide-I and amide-II bands located on the same amide are observed.

We have measured the relaxation of the initial magnetic permeability after sample demagnetization, in the temperature range 80 K < T < 420 K, in polycrystalline barium hexaferrites with a Ba : Fe ratio in the initial composition of 1:18 corresponding to stoichiometric W phase. The materials were sintered under different temperature and oxygen pressure conditions. The results represented by isochronal curves show the existence of up to four relaxation processes. Additional thermo-gravimetric and X-ray diffraction studies reveal the successive formation of M, X, and W hexagonal phases with the increase of the sintering temperature. In this framework, we ascribe the relaxation processes to the progressive increase of ferrous cations in the different sites within the hexagonal lattice. Index Terms--Barium ferrites, disaccommodation, hexagonal ferrites, magnetic aftereffect.

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.

Research has been conducted on the RNA hairpin tetraloops. The analysis of the tetraloops' dynamics via fluorescent spectroscopy and fluorescence-detected temperature-jump relaxation has been performed.

Transient absorbance pump-probe spectroscopy is used in studying the photoinduced electron transfer reactions in a porphyrin-viologen complex. Results indicate relaxation from the S2 to the S1 state in the wavelength region from 430 nm to 650 nm. Electron transfer occurs directly from the S2 state since the ZnTPPS(super 4-) to MV(super 2+) electron transfer could be time resolved. The back electron transfer took place with a lifetime of 0.8 plus/minus 0.1 ps.

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.

The dynamics of micellization on a dodecylpyridinium iodide/water system has been studied through photon correlation measurements. It has been noted that large micelles are formed after the temperature goes down to 25 degrees C from 80 degrees C. The micellar radius exhibits extremely long relaxation times which may take several hours. The unfavorable equilibrium concentration of intermediates of submicellar size prevents the nucleation of micelle aggregates. This results in a nonequilibrium distribution with an excess of large micelles during thermal equilibrium.

The relaxation phenomena of positive charges in thin gate oxides has been studied by measuring the applied gate voltage shifts (delta-V(sub FN)) at various constant Fowler-Nordheim current stresses. The formation and relaxation of positive charges have been analyzed from injections from the gate and from the substrate. Results show that there is a logarithmic relation between (delta-V(sub FN)) and the relaxation time. The transient current is inversely proportional to the relaxation time. These results are consistent with those obtained from tunneling front model.

We discuss, in terms of 1D and 2D micromagnetic models, the basic characteristics of the demagnetization mechanisms acting in hard magnetic materials. This includes the study of the hysteretic and relaxational processes and, particularly, the investigation of the temperature dependence of coercivity. From our results we conclude that, even in highly anisotropic materials, demagnetization should be described in terms of nucleation and propagation of finite magnetic moment structures of the domain wall type.

The dynamics of methyl groups are measured by calculating the 2H T(sub 1) and T(sub 1-rho) relaxation times in proteins which are uniformly C(super 13) labeled and partially deuterated. This new method of measurement is based on a constant-time H(super 1)-C(super 13) HSQC sequences, and requires mathematical interpretation. The relaxation nature of CH2D methyl groups establish that relaxation rates can be measured accurately. The sidechain dynamics of the C-terminal SH2 domain from phospholipase C(sub gamma-1) are also determined using the new method.

Theoretical investigations are performed to measure the electron-electron and electron-phonon relaxation rates in a hot electron microbolometer. The Born approximation is used in conjunction with the Thomas-Fermi theorem on Coulomb interactions to describe the different relaxation parameters, such as the branching ratio and electromagnetic noise density. Results show that these relaxation processes increase the bolometer's effective thermal conductance and significantly influence bolometer noise.