نتایج جستجو برای: charge density

تعداد نتایج: 532561  

Journal: :physical chemistry research 0
heydar ali shafiei gol university of sistan and baluchestan mehdi noura university of sistan and baluchestan, zahedan, iran.

the storage capacity of hydrogen on na-decorated born nitride nanotubes (bnnts) is investigated by using density functional theory within quantum espresso and gaussian 09. the results obtained predict that a single na atom tends to occupy above the central region of the hexagonal rings in (5,0) and (3,3) bnnt structures with a binding energy of -2.67 and -4.28 ev/na-atom respectively. when a si...

Journal: :journal of nanostructures 2014
h. a. shafieigol h. a. najari

in this research, structural and electronic properties of zncdn-1ten clusters (n=1-10) have been studied by formalism of density functional theory and using the projector augmented wave within local density approximation. the structural properties (such as bond length/angle and coordination number), electronic and optical properties (such as binding energy, kohn-sham spectrum and partial charge...

Journal: :molecular biology research communications 2015
marjan rafiee masoumeh javaheri

tyrosinase is a multifunctional copper-containing enzyme. it can catalyze two distinct reactions of melanin synthesis and benzaldehyde derivatives, which are potential tyrosinase inhibitors.  to find the relationships between charge distributions of benzaldehyde and their pharmaceutical behavior, the present study aimed at investigating nuclear quadrupole coupling constants of quadrupolare nucl...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 2008
alireza badiei razieh vahidifar abed hasheminasab

based on the {s+, i-} pathway, the concentration of surfactant and surface charge density of silanolate groups control the phase transition from lamellar, to hexagonal through cubic form. the high surface charge density of silanolate groups was observed for the lamellar phase. with decrease of molar concentration of surfactant on the gel, the yield of reaction decreases and the stability of mes...

Journal: :international journal of nano dimension 0
s. jalili department of chemistry, k. n. toosi university of technology,tehran, iran. computational physical sciences research laboratory, department of nano-science, institute for studies in theoretical physics and mathematics (ipm),tehran, iran r. vaziri department of chemistry, k. n. toosi university of technology,tehran, iran.

first principle calculations were performed using density functional theory within the local spin density approximation (lsda) to understand the electronic properties of au(100)+tbt system and compare the results with au(100) and bulk au properties. band structure, the total dos and charge density for these materials are calculated. we found that the homo for au(100)+tbt becomes broader than au...

Journal: :journal of physical & theoretical chemistry 2014
m. anafcheh f. naderi m. ezatvar h. masoomi

dft calculations were applied to evaluate the electronic and magnetic properties of zigzag bc2nnanotubes based on the 13c, 15n, and 11b nmr parameters and natural charge analysis. weconsidered three types of zigzag nanotubes, zz-1, zz-2, and zz-3 (n, 0) with n = 8, 12, and 14. theobtained results indicated the divisions of the electrostatic environments around c nuclei into a fewlayers, consist...

Journal: :journal of oil, gas and petrochemical technology 2014
sedigheh ghazvini mohammadreza omidkhah nasrin manouchehr nikazar

this study has been investigated, the effects of three different polar polyacrylamides (anionic, cationic, and nonionic) on asphaltene deposition in porous media. all experiments were carried out in various dead oil flow rates (0.2, 0.1 and 0.02 cc/min) and different polymer concentrations (500, 2500, 4000 ppm). the results indicated that asphaltene precipitation was affected by the presence of...

Journal: :علوم و تکنولوژی پلیمر 0
احمد ربیعی مهدی گیلانی هاجر جمشیدی

synthetic water soluble acrylamide-based polymers have wide range of ap-plications  in  the  feld  of  soil  establishment  and  non-desertifcation.  in  this research, the acrylamide-based anionic polyelectrolytes were prepared by  solution polymerization. the polymerization was carried out using aibn as a radical initiator and at different degrees of anionic charges ranging between 10% and 30...

Journal: :iranian journal of science and technology (sciences) 2012
m. waseem

zirconium dioxide, commonly known as zirconia, is an interesting material and is receiving growing attention due to its excellent mechanical properties. the solid was characterized for surface area measurements, scanningelectron microscopy (sem), energy dispersive x-ray diffractometry (edx) and potentiometric titrations. surface titrations were carried out at the temperature range 303 to 323k i...

پایان نامه :وزارت علوم، تحقیقات و فناوری - پژوهشگاه دانشهای بنیادی (مرکز تحقیقات فیزیک نظری و - پژوهشکده علوم نانو 1392

among the low–dimensional allotropes of carbon, nanotubes and graphene have attracted very much attention from nano–science and nanotechnology specialists. they have been proposed as building blocks in nanometer device engineering. however, these structures are not defect–free. in this thesis, we focused on defective carbon nanotubes and graphene, and studied the effect of couple of very common...

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