نتایج جستجو برای: density distribution

تعداد نتایج: 974041  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه یاسوج - دانشکده علوم 1391

in this investigation the effect of external field on the electron density of nanostructures of cds, cdse, cdte, gaas and polymeric structure of three, four, five and six units of cds as a kind of nanosolar cells has been studied theoretically. as modeling this system in nanodimension, molecular structures has used. specific properties of molecular structures permit us to consider different sym...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه ارومیه 1377

the methods which are used to analyze microstrip antennas, are divited into three categories: empirical methods, semi-empirical methods and full-wave analysis. empirical and semi-empirical methods are generally based on some fundamental simplifying assumptions about quality of surface current distribution and substrate thickness. thses simplificatioms cause low accuracy in field evaluation. ful...

Journal: :journal of ornamental plants 2015
fatemeh bidarnamani elham sanatgar mehdi shabanipoor

the two-spotted spider mite, tetranychus urticae koch (acari: tetranychidae), is an economically important pest of ornamental plant in iran. the population abundance and spatial distribution were studied on five rosa cultivars including maroussia, wendela, elderado, wenedetta, and hot lady during two growing seasons of 2011 and 2012 in greenhouse. the k parameter, index of dispersion, lloyd’s m...

1994
Barnali Gupta Debashis Pal Robert Drago Jonathan Hamilton John Heywood William Holahan

Recent work suggests that Cournot oligopolists competing in a spatial model, with a uniform distribution of consumers, agglomerate in the center of the market. In this paper we analyze the robustness of this result with a general symmetric distribution of consumers and show that if the population density is "too thin" at the center of the market, then Cournot competition does not yield spatial ...

Journal: :iranian journal of medical physics 0
ali asghar mowlavi associate professor, physics dept., faculty of sciences, sabzevar tarbiat moallem university, sabzevar, iran majed yazdani m.sc of physics, physics dept., faculty of sciences, sabzevar tarbiat moallem university, sabzevar, iran

introduction: clinical application of encapsulated radioactive brachytherapy sources has a major role in cancer treatment. in the present research, the effects of different tissue densities on the dose distribution of a 103pd brachytherapy source in a spherical phantom of 50 cm radius have been studied. material and methods: as is well known, absorbed dose in tissue depends to its density, but ...

Journal: :international journal of advanced biological and biomedical research 2013
m.r. hemami s.s. mohaghegh a. rohina s. sobhani ardakani

since density is considered as one of the most important numerical indices to explain quantitative values of a plant community by affecting on many aspects and activity of ecosystem, on the other hand, awareness about plants distribution pattern in environment is an essential preparation for measurement and study of vegetative cover, therefore, in this research determination of density and dist...

Journal: :Physical review. E, Statistical, nonlinear, and soft matter physics 2002
R Rajesh Dibyendu Das Bulbul Chakraborty Mustansir Barma

The effect of introducing a mass-dependent diffusion rate approximately m(-alpha) in a model of coagulation with single-particle breakup is studied both analytically and numerically. The model with alpha=0 is known to undergo a nonequilibrium phase transition as the mass density in the system is varied from a phase with an exponential distribution of mass to a phase with a power-law distributio...

Journal: :journal of agricultural science and technology 2010
r. kianpour y. fathipour k. kamali b. naseri

bionomics of aphis gossypii glover and its predators coccinella septempunctata l. and hippodamia variegata goeze were studied in varamin (tehran province) during 11th may to 5th october 2006 on eggplant crop, with the interaction (density dependence) between the aphid and either of the predators determined. the reliable sample size (number of leaves) with a maximum variation of 6.73% was about ...

Journal: :future of medical education journal 0
alireza mehridehnavi 1.medical physics and engineering department, medical school, isfahan university of medical sciences, isfahan, iran 2.school of optometry and visual science, university of waterloo, waterloo, canada. hossein mehri-dehnavi 3.department of physics, babol university of technology, babol, iran.

background: score worksheets have been extracted for phd candidates in epidemiology, microbiology and parasitology for the academic year of 1386-87. the main objective in this study is the impact and importance of different subjects on the discrimination results of admission. methods: extracted scores from worksheets are analyzed by minitab15 statistical toolbox. the regression values of differ...

Journal: :journal of mining and environment 2013
ali nejati kalateh amin roshandel kahoo

we inverse the surface gravity data to recover subsurface 3d density distribution with two strategy. in the first strategy, we assumed wide density model bound for inverting gravity data and in the second strategy, the inversion procedure have been carried out by limited bound density. wediscretize the earth model into rectangular cells of constant andunidentified density. the number of cells i...

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