a phase-locked loop (pll) based frequency synthesizer is an important circuit that is used in many applications, especially in communication systems such as ethernet receivers, disk drive read/write channels, digital mobile receivers, high-speed memory interfaces, system clock recovery and wireless communication system. other than requiring good signal purity such as low phase noise and low spu...

determination of uranium in natural water and complex solutions using ion exchange chromatography: a combined procedure using ion exchange chromatography and uv-vis spectrophotometry techniques has been developed to measure uranum in natural water and complex solutions. after conditicing , one hundred milli liters of sample solutions have been passed through an ion exchange column,pachked with ...

attempts have been made to study the thermodynamic behavior of 1,3 butadiene purification columns with the aim of retrofitting those columns to more energy efficient separation schemes. 1,3 butadiene is purified in two columns in series through being separated from methyl acetylene and 1,2 butadiene in the first and second column respectively. comparisons have been made among different therm...

abstract sensitive and precise voltammetric methods for the determination of trace amounts of furaldehydes, mainly as furfural (f) and 5-hydroxymethyl-2-furaldehyde (hmf), in waste waters and other matrices is described. determination of total furaldehyde at < ?g g-1 levels in alkaline buffered aqueous media was individually investigated. by the use of ordinary swv and adsorptive square wave ...

the present paper offers a postcolonial reading of two of the best novels by v. s. naipaul – half a life and the mimic men – in five chapters. the focus of this research is on different notions of postcolonial criticism and their application on the two novels as discussed from homi bhabha’s and frantz fanons points of view. having introduced the life and literary career of v. s. naipaul in th...

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: country’s fiber optic network, as one of the most important communication infrastructures, is of high importance; therefore, ensuring security of the network and its data is essential. no remarkable research has been done on assessing security of the country’s fiber optic network. besides, according to an official statistics released by ertebatat zirsakht company, unwanted disconnec...

two groups of students were assigned as experimental and control ones, and were given instruction on directed reading-thinking activities and after some treatment, they were post-tested. although the initial pre-test did not show any significant differences, the final post-test result revealed that the cooperative reading comprehension helped the experimental group. the cooperative students’...

hydrochlorothiazide (hct) is a diuretic agent which is shown to be effective in the treatment of hypertension. literature reports have demonstrated that urinary excretion data may be used to assess the bioavailability of various formulations containing this thiazide. also hct consumption by the athletes is one of the drugs which should be regulated by world anti-doping agency (wada), because of...

the present study was conducted to investigate the role of summary in teaching grammar process on pre-university students. to this end, 48 male pre-university students in semnan were participants. they were math class that we called experimental group and science class as control group. in order to make sure there was no significant difference in proficiency level of two groups. a pre-test wa...