نتایج جستجو برای: activation energy and sol

تعداد نتایج: 16997413  

Journal: :international journal of nano dimension 0
m. riazian department of engineering, tonekabon branch, islamic azad university, tonekabon, iran. a. bahari department of physics, university of mazandaran, babolsar, iran.

we report on the synthesis, morphology, chemically and structurally of tio2-cuo-sio2 nanostructure with different precursors molar ratio and calcined temperatures. in the present work, ternary reactive powders in the tio2-cuo-sio2 systems have been obtained using the sol-gel method, by the simultaneous gelation of all cations. the compounds and other elements change in special chemical and phys...

Journal: :international journal of nano dimension 0
m. riazian department of engineering, tonekabon branch, islamic azad university, tonekabon, iran

we report on the synthesis, morphology, chemically and structurally of tio2-nio-sio2 nanostructure. the tio2-nio-sio2 nanostructure was synthesized by a method based on the sol-gel method, by the simultaneous gelation of all cations. the coatings were deposited on dried soda-lime glass slides by spin coating. composite powders and coating on glass have been characterized by xrd, sem, edax, and ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه بیرجند - دانشکده علوم انسانی 1389

abstract amino acids are building blocks of proteins, and play a vital role in living beings existence and their functionality. the interaction of these compounds with metal ions is of great importance to biochemists, and chemists, because their functions can be utilized as a model in understanding enzymes mechanism for transport of metal ions to tissues. among twenty essential amino acids w...

میلانی‌مقدم, حسین, نصیریان, شهروز,

 In this letter, titanium dioxide nanoparticles (TiO2) were synthesized via a sol-gel method and combining titanium tetrachloride (TiCl4) and ethanol. The activation energy was investigated on the phase transformation from anatase to rutile in the presence and absence of ultrasound waves. The anatase nanocrystallites were only crystallized up to the calcination of 500 º C. By increasing the cal...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سیستان و بلوچستان 1390

a one dimensional dynamic model for a riser reactor in a fluidized bed catalytic cracking unit (fccu) for gasoil feed has been developed in two distinct conditions, one for industrial fccu and another for fccu using various frequencies of microwave energy spaced at the height of the riser reactor (fccu-mw). in addition, in order to increase the accuracy of component and bulk diffusion, instanta...

this thesis attempts to investigate the effects of prelistening activities on enhancing iranian efl learners` listening comprehension. the present study investigated ways in which learners` background knowledge could be activated in order to enhance their l2 listening comprehension by limiting the number of possible text interpretations prior to listening. the experiments conducted in this study examined the effect of prior knowledge and vocabulary teaching on iranian efl learners listening comprehension. the current study has two purposes: one is to investigate the effect of background knowledge on the second language listening comprehension of iranian intermediates and the other is to determine whether second language is facilitated by the introduction of unknown vocabularies in the form of prelistening activities. to conduct the study different instruments such as listening proficiency test and four listening tests such as pre and posttests were used and various statistical processes and techniques including paired-sample t-test, and analysis of variance (anova) were used. the findings of this study supported all three hypotheses tested. differences were found between the means of preteaching vocabulary variable, the background knowledge activation variable, and mean difference between these two strategies variable. subjects scored higher when the unknown words were taught in advance. likewise, subjects scored higher when they were asked some relevant questions about the topic than on those without them. there was, in addition, a significant difference between the means of preteaching vocabulary strategy and background knowledge activation strategy. in fact, preteaching vocabulary had a better effect in enhancing the students’ listening comprehension, in comparison to background knowledge activation strategy.

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد تهران مرکزی - دانشکده زبانهای خارجی 1390

this thesis attempts to investigate the effects of prelistening activities on enhancing iranian efl learners` listening comprehension. the present study investigated ways in which learners` background knowledge could be activated in order to enhance their l2 listening comprehension by limiting the number of possible text interpretations prior to listening. the experiments conducted in this stud...

پایان نامه :دانشگاه تربیت معلم - تهران - دانشکده علوم 1393

in this thesis, structural, electronical, and optical properties of inverse pervskite(ca3pbo) in cubic phase have been investigated.the calculation have been done based on density functional theory and according to generalized gradiant approximate (gga) as correlating potential. in order to calculate the configurations, implementing in the wien2k code have been used from 2013 version. first of ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه علامه طباطبایی 1391

this research is about the political economy of china in central asia. in this research the political & economic interactions affected on chinas political economy in central asia are examined. chinas goal of presence in central asia including political-security, economic and energy goals is described in one part. in another part, the trade relations between china and central asian countries ar...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه زنجان - دانشکده علوم انسانی و اجتماعی 1392

most specialists in the field of foreign language teachingconsiderreading skill as an interactive process between the reader’s prior knowledge and the text.accordingly, the activation of prior knowledge for an effective comprehension is very important. it is generally agreed that the pre-reading phase is the stage where this type of interaction and activation may be enhanced throughcertain stra...

The work is the report about stearic acid sol-gel synthesis method, magnetically, electricalcharacterization and activation energy of copper manganese oxide nanostructures. The CuMn2O4 nanostructures are synthesized at a temperature of 600°C using the sol-gel method. The structural analysis using X-ray diffraction (XRD) and Scherrer equation show that the crystallite size of CuMn2O4 is ab...

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