نتایج جستجو برای: attenuation relationships

تعداد نتایج: 275770  

H. Baharvand, M. Kardan, N. Sharafi, S. Sina, S.M.J. Mortazavi,

Background: Polyethylene composites including boron can be used as an effective neutron shield. Our investigation focuses on manufacturing borated polyethylene nano-composite. The purpose of this study is to design a radiation shield for use in both neutron and gamma fields. Materials and Methods: Borated polyethylene shields containing 2%, and 5% weight percentage of Boron nano-particles w...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیخ بهایی - دانشکده زبانهای خارجی 1391

phatic communion is a cultural concept which differs across cultures. according to hofstede (2001), the u.s. tends to have individualistic culture; however, asian countries tend to have collectivistic cultures. these cultures view phatic communion differently. in individualistic cultures like u.s., phatic communion reflects speakers’ socio-cultural relationships in conversations. to see whether...

Journal: :Journal of nuclear medicine : official publication, Society of Nuclear Medicine 2003
Chuanyong Bai Paul E Kinahan David Brasse Claude Comtat David W Townsend Carolyn C Meltzer Victor Villemagne Martin Charron Michel Defrise

UNLABELLED There has been considerable debate about the desirability of attenuation correction in whole-body PET oncology imaging. The advantages of attenuation correction are quantitative accuracy, whereas the perceived disadvantages are loss of contrast, noise amplification, and increased scanning time. In this work, we explain contrast changes between images reconstructed with and without at...

2013
Kenneth A. Miles Balaji Ganeshan Michael P. Hayball

Analysis of texture within tumours on computed tomography (CT) is emerging as a potentially useful tool in assessing prognosis and treatment response for patients with cancer. This article illustrates the image and histological features that correlate with CT texture parameters obtained from tumours using the filtration-histogram approach, which comprises image filtration to highlight image fea...

H. Canakci, I. Akkurt,

Background: Radiation shielding properties is an important for a material wish can be used the photon attenuation coefficients of clay produced using different rate of boron have been measured for the purpose of radioactive waste disposal. Materials and Methods: The measurement has been performed using gamma spectrometer contains NaI (Tl) detector at the photon energies of 662, 1173 an...

2015
J. S Ojo M. O Ajewole S. K Sarkar

Rain attenuation is a major shortcoming of microwave transmission. J.S Ojo1, 2, M.O Ajewole1, S.K Sarkar2. An improved approach of predicting rain attenuation cumulative. rain attenuation formula Approach for determining the values of rain attenuation at different.Attenuation due to rain is an important constraint in the designing of the microwave. The paper presents a new prediction model of r...

Golsar is located in north-west of Rasht the capital city of Guilan province. This region, according to standards 2800, is identified among the regions with relatively high risk of earthquake. A set of historical and instrumental seismicity data used in radius of 200 km which covers the period twelveth century until now. Kijko method has been applied for estimating for parameters considering of...

Journal: :Remote Sensing 2022

The modeling of laser transmission characteristics in complex seawater is fundamental for bathymetric and oceanographic detection systems. Because the factors affecting are independent one another, firstly, this paper, a Monte Carlo model propagation seawaters with suspended matter was established to study influence specific radius on underwater transmission. Secondly, depth number photons exti...

Journal: :Journal of the Acoustical Society of America 2021

Rayleigh waves are well known to attenuate due scattering when they propagate over a rough surface. Theoretical investigations have derived analytical expressions linking the attenuation coefficient statistical surface roughness parameters, namely, surface's root mean squared height and correlation length wave's wavenumber. In literature, three regimes been identified—the geometric (short wavel...

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