We present an empirical model for the electron energy relaxation time. It is based on Monte-Carlo simulation results and is applicable to all relevant diamond and zinc-blende structure semiconductors. The energy relaxation times are expressed as functions of the carrier and lattice temperatures, and in the case of semiconductor alloys, of the material composition. # 1999 Elsevier Science Ltd. A...

Nuclear magnetic resonance has emerged as a vital technique for investigating strongly correlated electron systems, and is particularly important for studying superconductivity. In this paper the basic features of NMR as a technique for probing the superconducting state are reviewed. Topics include include spin relaxation processes, studies of vortex lattices, and phenomena associated with unco...

We consider elastic wave velocities in fluid-saturated porous media with pore fluids distributed in “patches” (i.e., heterogeneity much larger than the typical pore size). We model elastic properties of such materials using inclusion-based effective medium theory (IBEMT). The standard IBEMT formulation assumes insufficient time during the wave cycle for pore fluids to flow in response to wave-i...

Dairy cream, as a suspension of lipid droplets in water, is a potentially useful magnetic resonance imaging (MRI) phantom material and an interesting material for studying fundamental relaxation mechanisms. Here we report a strong increase in the transverse relaxation rates with field strength for both the water and lipid protons in dairy cream. Also, studies at 4.7 T reveal a nonlinear respons...

A macroscopic constitutive equation is developed for a high-density cellulose insulation material with emphasis on the outof-plane stress relaxation behavior. A hypothesis is proposed where the total stress is additively composed by an out-of-plane visco-elastic isotropic contribution and an in-plane elastic orthotropic response. The theory is validated against out-of-plane stress relaxation, c...

In this paper, nonlinear static analysis of moderately thick plate made of functionally graded materials subjected to mechanical transverse loading is carried out using dynamic relaxation method. Mindlin first order shear deformation theory is employed to consider thick plate. Discretized equations are extracted for geometrically nonlinear behavior analysis.Loading Conditions and boundary condi...

Nuclear magnetic resonance relaxation is a fast and well-known method to get a measure of pore size distributions. To obtain reliable results, one needs to get information about influences like internal gradients evoked by paramagnetic impurities on the NMR relaxation signal. Therefore, we did a series of longitudinal and transverse relaxation experiments of samples with variable paramagnetic c...

A model is proposed that considers aging and rejuvenation in a soft glassy material as, respectively, a decrease and an increase in free energy. The aging term is weighted by an inverse of characteristic relaxation time suggesting that greater mobility of the constituents induces faster aging in a material. A dependence of relaxation time on free energy is proposed, which under quiescent condit...

In this paper we examine nonradiative processes ~cross relaxation and energy migration! vital for the generation of blue avalanche emission in Tm:LiYF4 crystals subjected to radiation near 648 nm. Time-domain and temperature-dependent measurements indicate that two sequential cross-relaxation processes dominate the nonradiative decays of the G4 and H4 excited states in this crystal. The occurre...

The electron spin properties are promising for future spin-driven applications. Silicon, the major material of microelectronics, also appears to be a perfect material for spintronic applications. The peculiarities of the subband structure and details of the spin propagation in ultra-thin silicon films in presence of the spin-orbit interaction and strain are investigated. The application of shea...