نتایج جستجو برای: energy correction

تعداد نتایج: 823665  

Journal: :journal of sciences, islamic republic of iran 2013
t. vazifehshenas s. saberi-pouya

we calculate the stopping power for heavy-ion diclusters moving in a strongly coupled two-dimensional electron gas system by using the local field corrected dielectric function at finite temperature. we obtain a parameterized local field correction factor based on a relation between the thermal compressibility and exchange-correlation energy in two-dimension. the interpolated parameter is deriv...

Journal: :iranian journal of basic medical sciences 0
shabnam oloomi department of medical physics, mashhad university of medical science, mashhad, iran hadi noori eskandari department of applied mathematics, school of mathematical sciences, ferdowsi university of mashhad, mashhad, iran seyed rasoul zakavi nuclear medicine research center, imam reza hospital, faculty of medicine, mashhad university of medical sciences, mashhad, iran peter knoll department of nuclear medicine wilhelminenspital vienna, austria faraz kalantari research center for nuclear medicine, tehran university of medical sciences, tehran, iran mohsen hajizadeh saffar department of medical physics, mashhad university of medical science, mashhad, iran

objective(s): in spect, the sinogram contains scatter and lack of attenuated counts that degrade the reconstructed image quality and quantity. many techniques for attenuation and scatter correction have been proposed. an acceptable method of correction is to incorporate effects into an iterative statistical reconstruction. here, we propose new maximum likelihood expectation maximization (mlem) ...

2007
M. M. Martins C.L.P. Maurício K. C. S. Patrão A. X. da Silva

Neutron individual monitoring is considerably less established than photon individual monitoring. The main difficulty is the impossibility to find a detector that covers the large occupational neutron energy range. All commercial individual monitors have strong energy dependence. Another difficulty is to calibrate an individual neutron monitor in the ISO 21909 established energy operational ran...

2009
Hendrik Huwald Chad W. Higgins Marc-Olivier Boldi Elie Bou-Zeid Michael Lehning Marc B. Parlange

[1] Most standard air temperature measurements are subject to significant errors mainly due to sensor heating by solar radiation, even when the measurement principle is accurate and precise. We present various air temperature measurements together with other measurements of meteorological parameters using different sensor systems at a snow-covered and a vegetated site. Measurements from natural...

2006
Zhengrong Ying Ram Naidu Carl R. Crawford

Single energy computed tomography (CT) scanners use measurements of densities to detect explosives in luggage. It is desirable to apply dual energy techniques to these CT scanners to obtain atomic number measurements to reduce false alarm rates. However, the direct application of existing dual energy techniques has practical problems, such as, approximation errors and lack of boundary constrain...

2012
Pablo Sartori Simone Pigolotti

We study stochastic copying schemes in which discrimination between a right and a wrong match is achieved via different kinetic barriers or different binding energies of the two matches. We demonstrate that, in single-step reactions, the two discrimination mechanisms are strictly alternative and can not be mixed to further reduce the error fraction. Close to the lowest error limit, kinetic disc...

2008
G. Royer

The coefficients of different mass formulae derived from the liquid drop model and including or not the curvature energy, the diffuseness correction to the Coulomb energy, the charge exchange correction term, different forms of the Wigner term and different powers of the relative neutron excess I = (N − Z)/A have been determined by a least square fitting procedure to 2027 experimental atomic ma...

Journal: :Physical review. E, Statistical, nonlinear, and soft matter physics 2006
Yong Kong

The classical monomer-dimer model in two-dimensional lattices has been shown to belong to the "#P-complete" class, which indicates the problem is computationally "intractable." We use exact computational method to investigate the number of ways to arrange dimers on mxn two-dimensional rectangular lattice strips with fixed dimer density rho . For any dimer density 0<rho<1 , we find a logarithmic...

Journal: :Physics in medicine and biology 2004
Myung Hwan Jeong Yong Choi Yong Hyun Chung Tae Yong Song Jin Ho Jung Key Jo Hong Byung Jun Min Yearn Seong Choe Kyung-Han Lee Byung-Tae Kim

The purpose of this study was to improve the performance of a small gamma camera, utilizing a NaI(Tl) plate and a 5" position sensitive PMT. We attempted to build a NaI(Tl) plate crystal system which retained all its advantages, while at the same time integrating some of the advantages inherent in an array-type scintillation crystal system. Flood images were obtained with a lead hole mask, and ...

Journal: :journal of physical & theoretical chemistry 2009
f. naderi m. yari f. mollaamin a.r. ilkhani m. khaleghian

interaction of meso — tetrakis (p-sulphonato phenyl) porphyrin (hereafter abbreviated to tspp)with na+ has been examined using hf level of theory with 6-31g* basis set. counterpoise (cp)correction has been used to show the extent of the basis set superposition error (bsse) on thepotential energy curves. the numbers of na+ have a significant effect on the calculated potentialenergy curve (includ...

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