نتایج جستجو برای: source shape
تعداد نتایج: 600126 فیلتر نتایج به سال:
Alzheimer's disease (AD) is a no-cure disease that has been frustrating the scientists for many years. Analyzing the disease has become an important but challenging research topic. The shape analysis of the sub-cortical structure of AD patients has been commonly used to understand this disease. In this paper, we assess the feasibility of using shape information on the hippocampal (HP) surfaces ...
Crystals bent to logarithmic spirals have been used in applications where large acceptance of divergent x-rays from a small source is needed [1]. Small acceptances can be easily handled with cylindrically bent crystal. In cases where larger acceptances are needed differential bending may be adequate [2]. However, the largest acceptance is obtained from a flat crystal plate when bent into the lo...
We propose a new method for phase retrieval that uses partially coherent illumination created by any arbitrary source shape in Köhler geometry. Using a stack of defocused intensity images, we recover not only the phase and amplitude of the sample, but also an estimate of the unknown source shape, which describes the spatial coherence of the illumination. Our algorithm uses a Kalman filtering ap...
In the present study, analytical solutions are developed for three-dimensional advection-dispersion equation (ADE) in semi-infinite adsorbing saturated homogeneous porous medium with time dependent dispersion coefficient. It means porosity of the medium is filled with single fluid(water). Dispersion coefficient is considered proportional to seepage velocity while adsorption coefficient inversel...
In the present study, analytical solutions are developed for three-dimensional advection-dispersion equation (ADE) in semi-infinite adsorbing saturated homogeneous porous medium with time dependent dispersion coefficient. It means porosity of the medium is filled with single fluid(water). Dispersion coefficient is considered proportional to seepage velocity while adsorption coefficient inversel...
The shape of the human erythrocyte is normally maintamed in vivo as a biconcave disc for 120 days. In vitro. the cell shape can be altered readily by amphipathic cornpounds; however. given time and an energy source. the cells can recover the discoid morphology. An active shape control mechanism is postulated to regulate erythrocyte shape. The shape recovery process is a necessary element in rev...
There are many techniques available to approach reflectance-based shape recovery in appropriate fields of application [4]. For instance, three-source photometric stereo method may be used for generating height maps of a human face, a human hand, etc. As an example, the following figures show three input images generated by using Lambertian reflectance maps (Figure 1). Figure 2 shows the shape r...
A miniature X-ray source has been optimized for electronic brachytherapy. The cooling fluid for this device is water. Unlike the radionuclide brachytherapy sources, this source is able to operate at variable voltages and currents to match the dose with the tumor depth. First, Monte Carlo (MC) optimization was performed on the tungsten target-buffer thickness layers versus energy such that the m...
In this research, we have used 102 strong motion recordings from 2012 Ahar-Varzaghan earthquakes (Mw=6.5 and Mw=6.3) to study the form of attenuation of shear wave Fourier amplitude spectra of those two events. The analysis is carried out in a broad-band frequency range from 0.1 to 20 Hz. A bilinear shape for geometrical spreading is assumed based on nonparametric regression of the data. The hi...
A quadratic surface can be fitted to potential-field data within 3×3 windows, which allow us to calculate curvature attributes from its coefficients. Phillips (2007) derived an equation depending on the most negative curvature to obtain the depth and structural index of isolated sources from peak values of special functions. They divided the special functions into two categories: Model-specific...
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