A method is presented to determine the bulk elastic properties of isotropic elastic closed-cell foams from impedance tube sound absorption tests. For such foams, a resonant sound absorption is generally observed, where acoustic energy is transformed into mechanical vibration, which in turn is dissipated into heat due to structural damping. This article shows how the bulk Young's modulus, Poisso...

Cocaine produces its psychoactive and addictive effects primarily by acting on the brain's limbic system, a set of interconnected regions that regulate pleasure and motivation. An initial, short-term effect -- a buildup of the neurochemical dopamine -- gives rise to euphoria and a desire to take the drug again. Researchers are seeking to understand how cocaine's many longer term effects produce...

The transport of radioactive substances is, in many ways, necessary the context nuclear fuel cycle that aims to generate energy or radioisotopes. In event a possible accident, shock-absorbing parts reduce mechanical stresses on other components packaging, since large part kinetic is absorbed by shock absorber. To standardize design research reactor spent assembly devices numerical analysis, set...

Absiruct-We present analytical expressions for the frequency response of avalanche photodetectors (APD’s) with separate absorption and multiplication regions (SAM). The effect of the electric field profile in the multiplication layer on frequency response is considered for the first time. Previous theories have assumed that the multiplication layer is very thin and the peak electric field, whic...

A new approach, utilizing an elevated pressure reactor and high-resolution electron energy loss spectroscopy (HREELS), to the measurement of sticking coefficients of methane decomposition on Ru(0001) has been demonstrated. It has been shown that the detection, by Auger electron spectroscopy and photoelectron spectroscopy, of fractional monolayers of carbon on ruthenium is difficult because of t...

We have studied experimentally the temporal and spectral characteristics of an actively mode-locked laserdiode array in an external cavity as it evolves to the steady state. It is found that the buildup time to steadystate picosecond pulses takes less than 45 round trips. The number of clusters of the longitudinal-mode spectrum reduces during the evolution and finally approaches a steady-state ...