all analytical methods are generally based on the measurement of a parameter or parameters which are somehow related to the concentration of the species.an ideal analytical method is one in which the concentration of a species can be measured to a high degree precision and accuracy and with a high sensitivity. unfortunately finding such a method is very difficult or sometimes even impossible.in...

abstract part one: the electrode oxidation potentials of a series of eighteen n-hydroxy compounds in aqueous solution were calculated based on a proper thermodynamic cycle. the dft method at the level of b3lyp-6-31g(d,p) was used to calculate the gas-phase free energy differences ,and the polarizable continuum model (pcm) was applied to describe the solvent and its interaction with n-hydroxy ...

تهیه ترکیب فسفرتری کلرید بااستفاده از واکنش فسفر سفید(زرد) و گاز کلر در فاز محلول و درمقیاس آزمایشگاهی موردمطالعه قرارگرفت .پس از انتخاب مناسبتر روش و انتخاب بهترین شرایط کوشش درجهت طراحی واحد نیمه صنعتی انجام شد و توانستیم دراین راستا به تولید 10 کیلوگرم درساعت باخلوص 99/5 درصد برسیم . abstract the preparation of phosphorous trichloride by the reaction of white phosphorous and chlorine gas in ...

abstract deviation or in other words committing a crime is literally a social problem. this research that was conducted in 1389 and 1390 has tried to investigate the causes of crimes committed by young male inmates qazvin central prison and effective variables on their tendency to deviation. accordingly after collecting theoretical framework and offering theoretical model including both hirsch...

abstract due to the growing importance and influence of the self of the teacher in the field of educational and cognitive psychology, the current study intended to investigate the relationship between three teacher qualities and characteristics, i.e. teacher self efficacy, self regulation, and success as perceived by their learners. the study aimed at finding whether teacher self efficacy an...

for several years, researchers in familiarity of efl teachers with post-method and its role in second and foreign language learners’ productions have pointed out that the opportunity to plan for a task generally develops language learners’ development (ellis, 2005). it is important to mention that the critical varies in language teaching was shown is the disappearances of the concept of method ...

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...

the purpose of this study is to investigate the relationships between teachers’ immediacy behaviors and iranian students’ willingness to talk in english classes. analysis of the results from willingness to talk scale represents a relatively high level of willingness to talk in english classrooms among iranian language learners. the total mean score of students’ willingness to talk was 66.3 ou...

this research was conducted in two protect and destroy region in the middle zagros, in illam province. in order to identification of ecological species group and evaluate density of regeneration, effect of many factors such as protection, vegetation, physiographic factors, physical and chemical properties of soil in study locations were studied. to achieve these purpose number of 54 plots using...