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 ...

since the 1960s the age effects on learning both first and second language have been explored by many linguists and applied linguists (e.g lennerberg, 1967; schachter, 1996; long, 1990) and the existence of critical period for language acquisition was found to be a common ground of all these studies. in spite of some common findings, some issues about the impacts of age on acquiring a second or...

Mining, industrial and agricultural activities can result in considerable soil pollution by heavy metals (HMs). One of the methods to control this pollution is application of adsorbent minerals. The purpose of this study was to compare the effects of adsorbent minerals (bentonite, zeolite and sepiolite) on transfer of some heavy metals (i.e., Pb, Zn and Cd) from soil to tissues of sunflower (He...

due to the limiting workspace of parallel manipulator and regarding to finding the trajectory planning of singularity free at workspace is difficult, so finding a best solution that can develop a technique to determine the singularity-free zones in the workspace of parallel manipulators is highly important. in this thesis a simple and new technique are presented to determine the maximal singula...

‏‎applications such as high definition viedeo reproduction, portable computers, wireless, and multimedia demand, and ever-increasing need for ligh-frequency high-resolution and low-power analog-to-digital converters. flash, two-step flash, and pipeline convertors are fast but consume large amount of power and require large area. to overcome these problems, successive approximation converter blo...

the effect of the presence of perforations on he stresses of a plate is a problem which is of great interest in structural design and in the mathemattical theory of elasticity. among the many hole patterns that are likely to require consideration is the ring of equally spaced circular holes. the present worke investigates stress & strain analysis of a thin isotropic circular plate containing a ...

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...

this research is a study on indicators of listening instruction in iranian english as a foreign language (efl) curriculum at guidance school and high school educational levels. this thesis aims at determining: a) the indicators of listening instruction at guidance school and high school efl curriculum. b) the indicators of listening instruction in irans guidance school and high school efl curri...

recent years have witnessed an increased attention to form focused instruction and consciousness raising activities (ellis, 2002; doughty & williams, 1998) on the one hand and extensive and meaningful exposure to the target language (klapper & rees, 2003; day & bamford, 1998) on the other. due to significance attributed to above mentioned issues by scholars, this study attempted to bridge them ...

one of the most commonly used techniques to reduce the corrosion rate of rebar in concrete is addition substances named corrosion inhibitors into the concrete. corrosion inhibitor is chemical compounds that were added to concrete to prevent corrosion of steel in concrete. sodium nitrate is a type of anodic inhibitors that this study investigatesthe effect of this inhibitor on the properties of ...