نتایج جستجو برای: mass attenuation coefficient
تعداد نتایج: 679612 فیلتر نتایج به سال:
In this study, time-resolved optical coherence tomography (OCT) scanning images of the process of water diffusion in the skin that illustrate the enhancement in the backscattered intensities due to the increased water concentration are presented. In our experiments, the water concentration in the skin was increased by soaking the hand in water, and the same region of the skin was scanned and me...
Tomographic images with absolute units have been reconstructed successfully from Small Angle X-ray Scattering (SAXS) intensities of an interdiffusion layer a precipitation strengthened model alloy cut multilayered Al/Al–Zn/Al sample after heat treatment. Cross sectional specimen Zn concentration distribution was obtained the mass attenuation coefficient; volume fraction precipitates SAXS integr...
Average vertical attenuation coefficients, K(av), for irradiance calculated by linear regression of ln E(z) on z through the euphotic zone or from two irradiance values in a certain depth interval, are useful but somewhat arbitrary procedures for estimating these important apparent optical properties of the ocean. A more fundamental approach is to calculate an irradiance-weighted coefficient, K...
A relaxation process, with the associated phenomenology of sound attenuation and sound velocity dispersion, is found in a simulated harmonic Lennard-Jones glass. We propose to identify this process with the so-called microscopic (or, instantaneous) relaxation process observed in real glasses and supercooled liquids. A model based on the memory function approach accounts for the observation and ...
In this paper, we propose an iterative beam hardening correction method that is applicable for the case with multiple materials. By assuming that the materials composing scanned object are known and that they are distinguishable by their linear attenuation coefficients at some given energy, the beam hardening correction problem is converted into a nonlinear system problem, which is then solved ...
The determination of the local mass per unit area m /A=erdt and the thickness of a specimen is an important aspect of its characterization and is often required for material quality control in fabrication. We discuss common methods which have been used to determine the local thickness of thin specimens. We then propose an x-ray technique which is capable of determining the local thickness and t...
Classical radiative transfer programs are based on the plane-parallel assumption. We show that the Gershun equation is valid if the irradiance is averaged over a sufficiently large area. We show that the equation is invalid for horizontal areas of the order of tens of meters in which horizontal gradients of irradiance in the presence of waves are much larger than vertical gradients. We calculat...
An exact expression for the remotely sensed reflectance (RSR, upwelling radiance divided by downwelling scalar irradiance) just beneath the surface of the ocean is derived from the equation of radiative transfer. It is shown that the RSR at a given depth in the ocean depends only on the inherent optical properties, the attenuation coefficient for upwelling radiance, and two shape factors that d...
Precise measurement of void coefficient in two phase flow is one of important parameters in thermal hydraulic parameters such as average density, two phase flow pressure drop and two phase flow pattern. In this study the void coefficient has been correlated experimentally based on attenuation coefficient gamma ray emitted form 137Cs source passing a rectangular channel. The average void fractio...
the effects and influences of various parameters upon the efficiency and the overall volumetric mass transfer coefficients are important subjects to be studied in most liquid-liquid extraction processes. one of these important parameters is surface active agent (surfactant). in this paper, in order to study the effect of sodium dodecyl sulfate (sds) concentration on the efficiency and the avera...
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