نتایج جستجو برای: Size dependent effect

تعداد نتایج: 2639806  

پایان نامه :وزارت علوم، تحقیقات و فناوری - پژوهشگاه دانشهای بنیادی (مرکز تحقیقات فیزیک نظری و - پژوهشکده علوم نانو 1392

among the low–dimensional allotropes of carbon, nanotubes and graphene have attracted very much attention from nano–science and nanotechnology specialists. they have been proposed as building blocks in nanometer device engineering. however, these structures are not defect–free. in this thesis, we focused on defective carbon nanotubes and graphene, and studied the effect of couple of very common...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه فردوسی مشهد - دانشکده ادبیات و علوم انسانی دکتر علی شریعتی 1392

a large number of single research studies on the effects of strategy-based instruction (sbi) in teaching english as a foreign or second language has been conducted so far. however, the lack of a comprehensive meta-analysis targeting the effectiveness of english language sbi is observed. moreover, the findings of experimental studies regarding the context of the english language, proficiency lev...

Journal: :journal of petroleum science and technology 2015
ahmad tavasoli saba karimi rohollah keyaei

the influence of mo particle size on the catalytic activity and product selectivity of alkalized mos2 nanocatalysts has been investigated. nanocatalysts are prepared using a microemulsion technique with water-to-surfactant ratios of 1-12. three different techniques, including xrd, tem, and hydrogen chemisorption were used to determine the molybdenum average particle size and their activity and ...

پایان نامه :دانشگاه تربیت معلم - تهران - دانشکده روانشناسی و علوم تربیتی 1391

the purpose of this study was the relationship between problem – solvi ability with fdi cognitive style of students.the research method was correlation method. for data analysis pearson test was used. statistical society in this research was all the students of alligoodarz city in 1391-92 year.to sampling of statiscal population was used sampling multi-stage random the size of sample selected 2...

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 بیرجند 1388

a significant problem in multicarrier communication systems is the necessity to reduce the value of papr (peak-to-average power ratio) of transmitting signal. in this thesis we study the effect of the system parameters such as coding and modulation types on papr and ultimate ber in a mc-cdma system. in this study we consider fading channel as well as the nonlinearity of transmitter’s amplifier ...

2016
Joris Meurs

PURPOSE The aim is of this study was to show the poor statistical power of postmortem studies. Further, this study aimed to find an estimate of the effect size for postmortem studies in order to show the importance of this parameter. This can be an aid in performing power analysis to determine a minimal sample size. METHODS GPower was used to perform calculations on sample size, effect size, ...

Journal: :ecopersia 2013
mohammad reza kalbassi seyed ali johari mahdi soltani il yu

in order to understand the importance of particle size and agglomeration for nano-eco-toxicological studies in aquatic environments, the acute toxicity of two different types (suspended powder and colloidal) of silver nanoparticles (agnps) were studied in alevin and juvenilerainbow trout. fish were exposed to each type of agnps at nominal concentrations of 0.032, 0.1, 0.32, 1, 3.2, 10, 32, and ...

Journal: :international journal of nanoscience and nanotechnology 2013
p. boroojerdian

semiconductor nanoparticles exhibit size dependent properties due to quantum confinement effect that arenot present in their bulk counterparts. in this work, extremely fine and pure sno2 nanoparticles of ~1.1nm size were synthesized by a solution process, in which amorphous precipitate of sno2 was crystallizedby microwave heating. the particles sizes varied from ~1.1 to ~2.7 nm. by xrd analysis...

S Rahmanian Sh Hosseini Hashemi,

The impetus of this study is to investigate the chaotic behavior of a size-dependent nano-beam with double-sided electrostatic actuation, incorporating surface energy effect and intermolecular interactions. The geometrically nonlinear beam model is based on Euler-Bernoulli beam assumption. The influence of the small-scale and the surface energy effect are modeled by implementing the consistent ...

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