نتایج جستجو برای: constant and variable stoichiometry

تعداد نتایج: 16869885  

In recent decades, fuel cells have been widely used in energy generation. In a PEMFC, considering the specific application, two types of oxidants are used. Durability tests, which are highly costly products,  are of crucial importance in evaluating the lifetime of fuel cells. The purpose of the present paper is to investigate the performance of a fuel cell by changing the type of oxidant from a...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشگاه پیام نور استان تهران - دانشکده اقتصاد و علوم اجتماعی 1389

چکیده: پژوهش حاضر به بررسی تطبیقی اعتماد اجتماعی در بین دبیران زن و مرد مقطع راهنمایی شهر ایلام می پردازد. امروزه در جوامع شاهد گسترش ارتباطات هستیم و با توجه به این که دامنه کنش های اجتماعی از حد روابط با آشنایان و دوستان فراتر رفته و به تعامل با کنشگران غربیه و نا آشنا گسترش یافته است، لزوم وجود اعتماد، بیش از پیش احساس می شود. اما با توجه به نقش دبیران در نهادهای آموزشی، در انتقال ارزش ها و...

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...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه اراک - دانشکده علوم انسانی 1393

this research study aimed to investigate the relationship between field-dependence/independence cognitive style and vocabulary learning strategies among iranian efl learners. ninety participants majoring in english translation at arak university were chosen. the participants were classified into two groups of field-dependent and independent based on the results of group embedded figure test (ge...

Journal: :The Journal of the Royal Aeronautical Society 1938

2016
Kai W. Wirtz Onur Kerimoglu

Autotrophic organisms reveal an astounding flexibility in their elemental stoichiometry, with potentially major implications on biogeochemical cycles and ecological functioning. Notwithstanding, stoichiometric regulation, and co-limitation by multiple resources in autotrophs were in the past often described by heuristic formulations. In this study, we present a mechanistic model of autotroph gr...

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد تهران مرکزی - دانشکده اقتصادو علوم اجتماعی 1390

today, the route for economic development in most countries is the same as international open competitive economy. economic institutes well known that supportive public economy belonged on the past and they may compete in the global economy. it is obvious that if they have no competitive potency or not familiar with competition technique, they may be devastated. banking system aims to collect t...

Journal: :تحقیقات مهندسی کشاورزی 0
سیدمحمدرضا امینی زاده دانشجوی کارشناسی ارشد رشتة آبیاری و زهکشی از گروه آبیاری دانشگاه تهران محمد محمودیان شوشتری استــاد گروه مهندسی عمران، دانشگاه شهید چمران اهواز عبدالمجید لیاقت استادیار گروه مهندسی آبیاری و آبادانی دانشگاه تهران. صلاح کوچک زاده دانشیار گروه مهندسی آبیاری و آبادانی دانشگاه تهران.

infiltration in furrow irrigation is 2-d which depends on both time and surface characteristics at which infiltration occurs. however, in many furrow irrigation models, infiltration is determined as a function of infiltration time opportunity, assuming the variation of weted perimeter is low along furrow. in order to compare the proposed asumptions, two zero-inertia furrow irrigation models wer...

2001
Serenella Cerrito Marta Cialdea Mayer

2010
Daniel Granadero Jorge Bordello Maria Jesus Pérez-Alvite Mercedes Novo Wajih Al-Soufi

The host-guest complexation between an Alexa 488 labelled adamantane derivative and beta-cyclodextrin is studied by Fluorescence Correlation Spectroscopy (FCS). A 1:1 complex stoichiometry and a high association equilibrium constant of K = 5.2 x 10(4) M(-1) are obtained in aqueous solution at 25 degrees C and pH = 6. The necessary experimental conditions are discussed. FCS proves to be an excel...

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