نتایج جستجو برای: activation analysis
تعداد نتایج: 3193728 فیلتر نتایج به سال:
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...
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 effect of mechanical activation on structural changes and kinetics of carbothermic reduction of hematite with graphite was studied in this research. hematite powder mixture with graphite (with stoichiometry ratio c/o=1) was milled for the time periods of zero to 50 hours, and the structural changes were studied using x ray diffraction (xrd). the effect of mechanical activation on the kineti...
introduction there is a growing interest in determining the concentration of various elements in food spices. in the present study, the instrumental neutron activation analysis (inaa) was employed to measure the trace elements in 11 commonly food spices consumed in tehran, iran. materials and methods the levels of k, mn, na, cl, v, br, al, and as were determined and their effects on human healt...
background: in addition to gas pollutants, many chemicals and air pollutants are in the form of particulate matter. particulate matter consists of a complex mixture of variable sized particles and physicochemical composition. these particles mainly contain minerals including fe, al, ca, k, cu, ti, mn, ni, v and their size, chemical composition and concentration are important to assess the exten...
شرح آزمایش این گونه است که نمونه توسط نوترون هایی که از چشمه خارج میشوند بمباران می شود. پس از برخورد نوترون به هسته پایدار هدف (نمونه) این هسته ناپایدار شده ودر زمانی کم یک پرتو گاما با انرژی مشخص از خود گسیل می کند. به همین علت این روش را تجزیه وتحلیل گامای آنی با استفاده از فعال سازی با نوترون((prompt gamma ray neutron activation analysis می نامند. اگر این پرتو در مسیر آشکارساز قرار بگیرد ت...
(large sample prompt gamma neutron activation analysis) روشی غیر مخرب برای تعیین کسرهای جرمی نمونه های بزرگ با ترکیب همگن ناشناخته می باشد و زمانی که نمونه بزرگ باشد، اثراتی مانند خودحفاظی نوترون و تضعیف گاما در تخمین مقدار ماده، سبب بروز مشکلاتی خواهند شد. برای تعیین مقدار دقیق نمونه، باید تصحیحاتی اعمال گردد، بنابراین ضرایب تصحیحی در نظر گرفته می شوند. در این پایان نامه ضریب خودحفاظی نوترون...
بیماری ام اس (multiple sclerosis) یک بیماری عصبی خود ایمن است که در آن، دستگاه ایمنی بدن به دلیل یا دلایل ناشناخته ای به دستگاه عصبی مرکزی حمله کرده و با از بین بردن غلاف سلول های عصبی، آسیب های متعددی را به بدن وارد می کند. یکی از عوامل بروز این بیماری می تواند متعادل نبودن میزان عناصر کم مقدار در بدن انسان باشد. تجزیه ی خون با استفاده از تجزیه به روش فعال سازی نوترونی (neutron activation anal...
in this study, the recycling possibility of residual oil fly ash (rofa) towards preparing activated carbon and its application in environmental remediation through adsorbing cu (ii) and pb (ii) ions from aqueous solutions were investigated. activated carbons were prepared using two different physical activation methods such as under steam flow at 950 0c, and combined steam and co2 flow at 850 0...
ige-mediated cell signaling, induced by cross-linking of high affinity receptor for ige (fcεri) in the presence of antigen (ag), is a well known mechanism described for mast cell activation in allergy and hypersensitivity reactions, which induces a spectrum of cellular responses such as secretion and up-regulation of cell surface fcεri. although for several years ige binding to fcεri was ...
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