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 study was designed to investigate the impacts of teachers self-disclosure on students foreign language classroom anxiety, attitude to english language learning and their achievement scores at the end of the term. there were 48 female learners of intermediate level. they were not randomly selected. there were one experimental group with 21 students and one control group with 27 students.the...

in new management approaches, in the organizations with inflexible structure, existing of red tapes and interruptions caused by limitations and also non-compliance with environmental changes, create demotivation among staff. with regard to the influence of job motivational potential and its relationship to the type of organizational structure( enabling and dissuasive), the goal of this research...

the aim of the present study was to investigate the frequency and the type of discourse markers used in the argumentative and expository writings of iranian efl learners and the differences between these text features in the two essay genres. the study also aimed at examining the influence of the use of discourse markers on the participants’ writing quality. to this end the discourse markers us...

abstract biometric access control is an automatic system that intelligently provides the access of special actions to predefined individuals. it may use one or more unique features of humans, like fingerprint, iris, gesture, 2d and 3d face images. 2d face image is one of the important features with useful and reliable information for recognition of individuals and systems based on this ...

learning a second or foreign language requires the manipulation of four main skills, namely, listening, reading, speaking, and writing which lead to effective communication. it is obvious that vocabulary is an indispensible part of any communication, so without a vocabulary, no meaningful communication can take place and meaningful communication relies heavily on vocabulary. one fundamental fac...

this thesis is presented 10 ghz voltage controlled ring oscillator for high speed application. the voltage controlled ring oscillator was designed and fabricated in 0.13یm cmos technology. the oscillator is 7-stages ring oscillator with one inverter replaced by nand-gate for shutting down in the ring oscillator during idle mode. tri-state inverter was used to control of 126 bit vector in ri...