fluorescence chemical sensors for the highly sensitive and selective determination of pb2+ , hg2+, co2+ and fe3+ ions in aqueous solutions are described. the ion sensing system was prepared by incorporating lipophilic ligand (l) as a neutral ion-selective fluoroionophore in the plasticized pvc membrane containing sodium tetraphenylborate or potasium tetrakis (p-chlorophenyl) borate as a liphoph...

this is an original study on the effect of a polyisobutylene – polydimethylsiloxane (pibpdms) block copolymer modifier used as an interfacial active agent on the dynamics behaviour of single newtonian drops suspended in a polyisobutylene (pib) newtonian matrix. the results were divided in two sections. the first part included the experiments carried out on the non-modified and 2% block cop...

in this thesis, a new optically active poly(amide-imide) (pai) was synthesized by the indirect polycondensation reaction of the l-phenylalanine based diacid chloride and 4,4?-diaminodiphenylether in the presence of triethylamine in n-methyl-2-pyrrolidone. the formation of pai was confirmed by ftir, 1h nmr and elemental analysis. in next step, the surface of titanium dioxide (tio2) nanoparticles...

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...

abstract abstract of thesis (includes summary, goals, execution methods, and results) story “al-obnosat al-bayza” is one of the short stories from “hanna mineh” collection. this story is a selection of lives of some humans during a voyage together, each of them is a symbol of human nature (love, mind, kindness) and examine social, cultural, and political aspects of governing system, and it...

مقدار تبخیر و تعرق حقیقی مزرعه یونجه واقع در باجگاه بوسیله روش تعادل آبیاری در 9 کرت آزمایشی و دولیسمتر از نوع وزنی بمنظور تعیین آب مصرفی گیاه یونجه تعیین شد. در طول مدت آزمایش مقدار آب موجود در خاک بوسیله نمونه برداری وزنی از خاک و دستگاه نوترون متر تعیین و مقدار تشعشع رسیده از خورشید بزمین و ساعات آفتابی روز نیز اندازه گیری شد. مقدار تبخیر و تعرق پتانسیل بوسیله روشهای modified blaney-criddle ...

data envelopment analysis (dea) is a powerful tool for measuring relative efficiency of organizational units referred to as decision making units (dmus). in most cases dmus have network structures with internal linking activities. traditional dea models, however, consider dmus as black boxes with no regard to their linking activities and therefore do not provide decision makers with the reasons...

in solvo-hydrothermal method, xrd pattern was indicated presence of intermediate of ammonium octatmolybdate and ammonium tetramolybdate, which were changed to stble phase of ?-moo3 annealing. sem images were indicated nanoparticle with semispheical morphology and tem image was demonstrated nanoparticles with a diameter size of 25nm. also in impregnate method. the xrd pattern was shown high crys...

the treatment of in completely formed pulpless teeth has presented considrable problems. these teeth have wide open apexes and the walls of the root canal diverge toward the apical tissues. mechanical preparation cannot be done in the normal manner beacause of the large initial size and the taper of apical part of the canal , a mechanical stop cannot be produced at the apex of the canal and , t...

به منظور جمع آوری و شناسایی کنه های بالاخانواده ی raphignathoidea باغات و مزارع شهرستان های ماکو و چایپاره، نمونه برداری هایی در فصل زراعی سال 1391 از خاک و اندام های هوایی صورت گرفت. در این مطالعه حدود 1200 اسلاید تهیه گردید که منجر به شناسایی 5 خانواده، 11 جنس و 31 گونه متعلق به بالا خانواده ی raphignathoidea گردید. از بین این تعداد 7 گونه برای فون دنیا و 8 گونه برای فون کنه های استان آذربایج...