the ac electrical behaviour of nano porous silicon (psi) with tio2 thin films was examined over the range of frequency 102 to 105 hz. porous silicon (psi) layers were obtained by electrochemical etching in hf solution and tio2 thin films were deposited on psi substrates by using electron beam evaporation technique at room temperature. the porosity of psi layer was found by using the gravimetric...

this study is focused on investigating the parameters of laser percussion drilling process of nickel-base super alloy inconel 718 with thickness of 1 mm. fiber laser with the power of 500 watts was used as the laser source. laser pulse frequency, duty cycle, laser power, focal point position, were assumed as the laser drilling process variables. the hole geometry features, i.e. entrance hole di...

Molecular dynamics simulations employing reactive potentials were used to determine the activation barriers to the dissolution of the amorphous SiO2 surface in the presence of a 2 nm overlayer of water. The potential of mean force calculations of the reactions of water molecules with 15 different starting Q4 sites (Qi is the Si site with i bridging oxygen neighbors) to eventually form the disso...

The difference between literature values of ultrasonic attenuation and absorption coefficients, defined as the scatter coefficient, was related to percent wet weight collagen concentration for brain, heart, liver, kidney, and tendon, in the range of 0.7 to 7 MHz. The comparison shows that as the ultrasonic frequency increases, the scatter coefficient increases, and the dependence of scattering ...

A simple semi-phenomenological model, which accurately predicts the dependence of thresholdcurrent for temperature of Resonant-phonon three well quantum cascade laser based on verticaltransitions is offered. We found that, the longitude optical phonon scattering of thermally excitedelectrons is the most important limiting factor for thermal performance of high frequency THz QCLs.In low frequenc...

We analyze the derivative nonlinear Schrödinger equation iqt + qxx = i ( |q|q ) x on the half-line using the Fokas method. Assuming that the solution q(x, t) exists, we show that it can be represented in terms of the solution of a matrix Riemann-Hilbert problem formulated in the plane of the complex spectral parameter ζ. The jump matrix has explicit x, t dependence and is given in terms of the ...

PURPOSE To demonstrate how reference data affect the quantification of the apparent diffusion coefficient (ADC) in long diffusion time measurements with diffusion-weighted stimulated echo acquisition mode (DW-STEAM) measurements, and to present a modification to avoid contribution from crusher gradients in DW-STEAM. METHODS For DW-STEAM, reference measurements at long diffusion times have sig...