نتایج جستجو برای: probably due to formation of soluble complexes
تعداد نتایج: 22215675 فیلتر نتایج به سال:
building on previous studies on the effectiveness of different types of written corrective feedback, the present study aimed at investigating whether direct focused corrective feedback and direct unfocused corrective feedback produced any differential effects on the accurate use of english articles by efl learners across two different proficiency levels (low and high). in current study, the par...
methodology non-native participants in this study were sixty ba students majoring in english literature and teaching english as a foreign language at khayyam university of mashhad. they were senior students, between 21 to 24 years old, who had studied english for at least three and a half years and had passed several courses including grammar, reading, conversation, and writing. this was assum...
in this thesis, a new optically active poly(amide-imide) (pai) was synthesized by the indirect polycondensation reaction of the l-phenylalanine based diacid chloride and 4,4?-diaminodiphenylether in the presence of triethylamine in n-methyl-2-pyrrolidone. the formation of pai was confirmed by ftir, 1h nmr and elemental analysis. in next step, the surface of titanium dioxide (tio2) nanoparticles...
The complexation of Cd2+ by diallyl disulfide (DADS) and diallyl sulfide (DAS) has been studied by differential pulse voltammetry. Stability constants, (log β), of the 1:1 (PbL) and 1:2 (PbL2) complexes, where L = ligand, were found to be in the range of ca. 5.8 - 6.2 and 9.6 -10.6, respectively. Complex formation is accompanied with a significant decrease in the peak current and the shift of t...
In this article cloud-point extraction (CPE) was used with chelating agent to extract uranium from aqueous solutions. The methodology used is based on the formation of metal complexes soluble in a micellar phase of surfactant. The metal ions complexes are then extracted into the surfactant-rich phase at a temperature above the cloud-point temperature. The effect of type of surfactants and ligan...
The complexation of Alkali metal cations by the water-soluble p-sulfonic acid calix(4)arenewas thermodynamically characterized using spectrophotometeric data which are consistentwith the formation of a 1:1 complex resulting from electrostatic interactions between thesulfonato groups and alkali metal cations. In this study, we determined the formationconstants (log K) of the complexes and have c...
the main purpose of this research was to:1.develop a coking model for thermal cracking of naphtha.2.study coke inhibition methods using different coke inhibitors.developing a coking model in naphtha cracking reactors requires a suitable model of the thermal cracking reactor based on a reliable kinetic model.to obtain reliable results all these models shall be solved simultaneously.for this pu...
a series of schiff bases of ni(ii) and cu(ii) using acetylacetone (acac), salicylaldehyde (sal), ethylenediamine (en), and o-phenylendiarnine (dabe) were prepared and characterized. the electronic spectra of some copper chelates in various organic solvents depend strongly on the solvent used and the d-d band of cu(ii) shifts to red with the increase of the donor number (dn) of solvent. the colo...
vascular fibrin formation were studied; ( I ) patients with preeclampsia; (2) those having treatment with ancrod (Arvin). In preeclampsia, soluble fibrin formation was greatly. increased in comparison with normal pregnant women. The isolated fibrin contained intact a, p and 7 chains; on polyacrylamide gel electrophoresis, no crosslinking of y chains could be found. A positive correlation was fo...
in this project, some new polyaspartimides, (pas)s, have been synthesized form michael addition reaction between new synthetic bismaleimide (bmi) and some aromatic diamines. a characteristic property of this polyaspartimides is a pendent carboxylic group, which introduced to these polymers from new bismaleimide. bismaleimides (bmi) is one of the interesting compounds, which can be self-polymeri...
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