نتایج جستجو برای: specific surface area and dm
تعداد نتایج: 17056430 فیلتر نتایج به سال:
In the present study, a type of graphitic mesoporous carbon (denoted as GMC) is synthesized and its structural properties were characterized by nitrogen physisorption isotherms, transmission electron microscopy and Raman spectroscopy. According to BET and BJH methods, the specific surface area (SBET) and the average pore diameter of GMC are estimated to be 720 m2/g and 3.4 nm, respectively....
This paper presents a new gel combustion method to synthesize palladium nanoparticles, palladium oxide (PdO) nanoparticles and palladium-palladium oxide nanocomposites. In the proposed method, there are some effective parameters including palladium chloride concentration, polyvinyl alcohol (PVA) concentration, acid concentration, solvent composition and combustion temperature that their values ...
hedging is a multi-purpose rhetorical strategy which is usually used in scientific arguments to secure ratification of claims, reduce the risk of negation, avoid conflict, manage disagreement and leave room for the audience to assess presented information. hedges are frequently used in research articles to mitigate the findings of research endeavors. the present research aims to investigate the...
This work describes the optical and structure properties of nickel sulfide and cobalt sulfide nanoparticles in ZSM-5 zeolite. The samples were obtained by sulfidation of the Ni2+ and Co2+ ion-exchange ZSM-5 zeolites in a Na2S solution at room temperature. The optical properties of the samples were studied by UV-visible spectroscopy. Their crystalline structure and morphology were studied by X-r...
abstract nowadays, industries cannot play a crucial role in national and international competitions. the tourism industry is no exception. tourism industry development as the most important economic sector and income generation is one of the key challenges of economic development in the world. therefore, countries were successful that take advantage of the capabilities of tourism sector using ...
textbooks play a crucial role in language learning classrooms. the problem is that among the great quantity of available textbooks on the market which one is appropriate for a specific classroom and a group of learners. in order to evaluate elt textbooks, theorists and writers have offered different kinds of evaluative frameworks based on a number of principles and criteria. this study evaluate...
Cryogen spray cooling (CSC) is an auxiliary procedure to dermatologic laser surgery which consists of pre-cooling the superficial skin layer (epidermis) during laser irradiation of subsurface targets to avoid non-specific epidermal thermal damage. While previous studies have investigated the interaction of cryogen sprays with microscopically smooth human skin models, it is important to recogniz...
this study was an attempt to investigate the effect of teaching meta cognitive strategies on iranian intermediate efl students speaking proficiency. in this study the researcher has employed metacognitive strategies taken from brown (2000) to teach speaking strategies to number of participants. the participants were intermediate students of shokouh language institute; they were divided into an ...
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