نتایج جستجو برای: chemical and thermal analysis
تعداد نتایج: 17354413 فیلتر نتایج به سال:
the purpose of this study was to examine the english language needs of medical students at tehran university of medical sciences . analysis of the needs took place for three groups: 320 undergraduate students, 30 postgraduate students and 20 university instructors. a triangulation approach to collect data was used in which a combination of the quantitative (using the questionnaires) and qualita...
بررسی ارزش غذایی تاغ و عمل آوری آن با سود و آهک در مراحل مختلف رشدبا استفاده از روش کیسه های نایلونی
abstract this study is carried out to determine the chemical composition in the three vegetative stages of the haloxylon sp., degradation parameters, with adding naoh and ca(oh2 ). for this purpose, in may and october and january 2010 enough some haloxylon sp. of the ammary area was prepared. crude protein and ash percentage are decrease, neutral detergent fiber percentage with pragress stage ...
In this study, hydroxyapatite (HA) nanocrystals have been synthesized via chemical precipitation technique. Diammonium hydrogen phosphate and calcium nitrate 4-hydrate were used as starting materials and sodium hydroxide solution was used as the agent for pH adjustment. The powder sample was evaluated by techniques such as scanning electron microscope, transmission electron microscope, Fou...
Zeolites are hydrated crystalline aluminosilicates of alkali and alkaline earth cations. Their three dimensional framework consist of [SiO4]- and [AlO4]- tetrahedra. Beside their low price and abundance, three main properties of zeolites i.e: adsorption, ion exchange and catalytical properties promote their versatile industrial applications. In Iran, lack of a systematic and comprehensive resea...
previous studies have aimed at testing a hypothesis but the present study is data-first research in which researcher tries to form a theory from data rather than the use of data to test a hypothesis. this study aims at exploring teachers perceptions of the strengths and weaknesses of the current syllabus for college preparatory course. eight experienced teachers were selected to collect data du...
abstract in this study, we synthesized a novel template polymer by using methacrylic acid (mma) as functional monomer, ethylene glycol dimethacrylate(egdma) as cross linker, 2,2-azobisisobutyronitrile (aibn) as initiator and olanzapine as targeted molecule in the presence of chloroform and acetonitrile as solvent. the products have been characterized and confirmed by (chn)elemental analysis,...
this study was conducted to determine the causes and outcomes of burn in patients referred to shahid mohammadi hospital in bandar abbass, southern iran, in which 212 burned patients were assessed from march 2007 to march 2008 .mean age of patients was 22.14 yr. heat contact was the main cause of burn with 92.5%. 49.1% of total burns occurred among less than 20 yr old people. mortality rate was ...
background: in recent years, natural products, especially natural antioxidants, play an important role in various fields. in fact, lippia citriodora is one of the medicinal plants which is cultivated in iran and it may be has potential antioxidant activity. objective: the chemical composition of lippia citriodora essential oil (lceo) has been determined. the total phenolic content and antioxida...
in this research, the effect of nanoclay on physiochemical, thermal and structural properties of urea formaldehyde resin (uf) was investigated. the prepared gluf resin was mixed mechanically with the 0.5, 1 and 1.5% nanoclay for 5 min at room temperature. the physicochemical properties of the prepared resins were measured according to standard methods. also, the thermal and structural changes i...
this study investigated the effect of prior knowledge on the listening comprehension performance of fl learners. twenty students, male and female, drawn from the two intact groups of the senior and junior english language and literature majors were chosen as the participants of this study . the two groups were then randomly assigned into the experimental and control group. the experimental gr...
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