a simple, sensitive and selective method for solvent extraction and spectrophotemetric determination of lanthanum (ii) europium (iii), and cerium (iii) is described , the rare earth metals are extracted into chloroform solution of n-phenylbenzohydroxamic acid (pbha) at ph 9-10 various parameters are studied to optimize the extraction conditions. the molar absorptivity is found to increase from ...

there are two major theories of measurement in psychometrics: classical test theory (ctt) and item-response theory (irt). despite its widespread and long use, ctt has a number of shortcomings, which make it problematic to be used for practical and theoretical purposes. irt tries to solve these shortcomings, and provide better and more dependable answers. one of the applications of irt is the as...

iv abstract this study examined the linguistic behaviors of two iranian efl teachers each of them teaching learners of two similar proficiency levels, a beginner level and an intermediate level, to investigate the relationship between the learners proficiency levels and the amounts and purposes for l1 use by the two teachers. the study was carried out to investigate whether there were differe...

w. a. dudek, m. shahryari, representation theory of polyadic groups, algebra and representation theory, 2010. و a. borowiec, w. a. dudek, s. duplij, bi-element representations of ternary groups, comminications in algebra 34 (2006). هدف اصلی این پایان نامه، معرفی نمایش های گروه های n-تایی و بررسی ویژگی های اصلی آن ها با تمرکز روی گروه های سه تایی است.

the purpose of this two-phase, sequential mixed methods study was to find out whether there were any decencies between male and female ma students’ theses regarding the common features of academic writing such as syntactic complexity, means of integrating cited information, and organizing arguments. i chose 10 male written theses and 15 female written theses in tefl and linguistics. in the firs...

the poor orientation of the restaurants toward the information technology has yet many unsolved issues in regards to the customers. one of these problems which lead the appeal list of later, and have a negative impact on the prestige of the restaurant is the case when the later does not respond on time to the customers’ needs, and which causes their dissatisfaction. this issue is really sensiti...

abstract nowadays, the science of decision making has been paid to more attention due to the complexity of the problems of suppliers selection. as known, one of the efficient tools in economic and human resources development is the extension of communication networks in developing countries. so, the proper selection of suppliers of tc equipments is of concern very much. in this study, a ...

over the past decades a number of approaches have been applied for forecasting mortality. in 1992, a new method for long-run forecast of the level and age pattern of mortality was published by lee and carter. this method was welcomed by many authors so it was extended through a wider class of generalized, parametric and nonlinear model. this model represents one of the most influential recent d...

abstract ion selective electrodes (ises) are electrochemical sensors that respond selectivity to the activity of ionic species. an ion-selective electrode is an electrochemical device that uses a thin selective membrane or film as the recognition element, and is an electrochemical half-cell equivalent to other half-cells of the zeroth (inert metal in a redox electrolyte). in common methods o...

abstract amino acids are building blocks of proteins, and play a vital role in living beings existence and their functionality. the interaction of these compounds with metal ions is of great importance to biochemists, and chemists, because their functions can be utilized as a model in understanding enzymes mechanism for transport of metal ions to tissues. among twenty essential amino acids w...