نتایج جستجو برای: while the temperature increasing resulted in nano

تعداد نتایج: 21287345  

In this study, the effects of nitrogen addition on the production of ultrafine/nano grained AISI 201L stainless steel by advanced thermo-mechanical process were investigated. Cast samples were first homogenized at 1200 °C for 4 h, hot-rolled at 1100 °C and finally, solution-annealed at 1150 °C for 2.5 h. Unidirectional and cross multipass cold rolling at 25 °C was carried out to 90% reduction i...

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد تهران مرکزی - دانشکده زبانهای خارجی 1392

the aim of the current study was to investigate the relationship among efl learners learning style preferences, use of language learning strategies, and autonomy. a total of 148 male and female learners, between the ages of 18 and 30, majoring in english literature and english translation at islamic azad university, central tehran were randomly selected. a package of three questionnaires was ad...

پایان نامه :دانشگاه تربیت معلم - تهران - دانشکده ادبیات و علوم انسانی 1389

abstract the primary purpose of this study was to explore the actual practices and cognitions of two groups of iranian eap teachers, i.e. language teachers and content teachers, with respect to teaching reading-comprehension and vocabulary. to this end, tehran university of medical sciences which authorizes both groups of teachers to teach eap courses was selected as the context of the study s...

Journal: :international journal of nanoscience and nanotechnology 2007
a. amrollahi a. a. hamidi a. m. rashidi

in this investigation the silicate nano structure of mcm-41 has been used for the production of nanofluid.the particles have negligible heat conductivity and therefore by their dispersion in a base fluid likewater, it is possible to study the increase of heat conductivity due to the brownian motion effects. in thiswork a suitable apparatus for the measurement of heat conductivity has been built...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سیستان و بلوچستان - دانشکده ادبیات و علوم انسانی 1392

the present study seeks to determine the effect of explicit instruction of metacognitive strategies on iranian high school students’ reading comprehension ability. it also attempts to investigate the relationship between the learners reading comprehension and metacognitive strategies. furthermore, the study investigates whether iranian efl female high school students are high, medium, or low me...

Journal: :journal of ultrafine grained and nanostructured materials 2015
sedigheh rashidi abolghasem ataie

in this research, the effect of different biopolymers such as polyethylene glycol (peg) and polyvinylalcohol (pva) on synthesis and characterization of polymer/cobalt ferrite (cf) nano-composites bymechanical alloying method has been systematically investigated. the structural, morphological andmagnetic properties changes during mechanical milling were investigated by x-ray diffraction (xrd),fo...

Blue nano pigments of CoAl2O4 were successfully prepared by polyol method. Two different groups of materials containing chloride and acetate compounds were used to synthesis the nano pigments. The nano pigments were calcinated at 1100 °C. The CoAl2O4 nano pigments were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), dynamic li...

Electrochemical impedance spectroscopy and gravimetric methods were carried out to analyze water uptake of thin polyurethane films separately filled with either hydrophobic or hydrophilic nano-silica. Correspondingly the impedance spectra and gravimetric data were interpreted in terms of movement of water within the coating and/or to the coating/metal interface. Although the obtained results fr...

Nano-structured lanthanum strontium cobalt ferrite, La0.6Sr0.4Co0.2Fe0.8O3 (LSCF), was successfully synthesized via co-precipitation method using metal nitrates as starting materials. Effects of precipitating agent and calcination temperature on the phase composition and morphology of synthesized powders were systematically studied using X-ray diffraction (XRD) and field emission scanning elect...

2017
Yang Zhao Xueqi Huang Bo Yu Xiaoyun Yuan Xianghua Liu

The microstructure, mechanical properties, and hydrogen permeation behavior of hot rolled enamel steel were investigated. Three coiling temperatures were adopted to gain different sizes of ferrite grain and TiC precipitates. The results show that a large number of interphase precipitates of nano-sized TiC can be obtained at coiling temperatures of 650 and 700 °C, while a few precipitates are fo...

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