ORIGINAL_ARTICLE
The Interaction of HCN Gas on the Surface of Pristine, Ga, N and GaN-Doped (4,4) Armchair Models of BPNTs: A Computational Approach
In this research, the interactions of HCN gas with pristine, Ga-, N- and GaN-doped of boron phosphide nanotube (BPNTs) were investigated by using density function theory (DFT). The structure, electrical and NQR parameters, quantum descriptors involving energy gap, global hardness, global softness, electrophilicity, electronic chemical potential and electronegativity were calculated. The adsorption energy values of the AI-BIV models were negative and the adsorption process was exothermic. GaN-doped impurity atoms increased the adsorption of HCN gas on the surface of nanotube and the GaN-doped model was favorable than other models. The NQR parameters of the fourth layer of pristine and N-doped models were more than those of other models due to the change of the geometrical parameters. The energy gap between LUMO and HOMO orbital changed slightly from 2.83-3.09 eV, with adsorption of HCN gas on the surface of BPNTs. The global hardness and ionization potential and natural charge of NBO calculations showed a charge transfer from the HCN molecule (nucleophile agent) to the nanotube models (electrophile agent).
https://www.physchemres.org/article_10307_a9040b096fcb97b794fe02c3abe00029.pdf
2015-12-01
265
277
10.22036/pcr.2015.10307
BPNTs
DFT
HCN interaction
Ga-
N- and GaN-doped
Mahdi
Rezaei Sameti
mrsameti@gmail.com
1
Department of Chemistry, Faculty of Science, Malayer University, Malayer, Iran
LEAD_AUTHOR
ORIGINAL_ARTICLE
An Efficient Method for Correlation of Vapor Pressure of Gaseous Compounds Containing C-H-O
Prediction of available vapor pressure data in the case of compounds containing C-H-O led to derivations and recommendations of standard equations for this property. The accuracy of vapor pressure estimations is essential to use as a basis to calculate acentric factor, thermal and equilibrium properties. In this study, according to the previous work, an accurate equation to estimate vapor pressure is developed to 130 pure C-H-O compounds as a function of reduced temperature and critical pressure. With new proposed equation, vapor pressures have been calculated in comparison with experimental data reported in literature for 2019 data points of 130 pure C-H-O compounds and the overall average absolute relative deviation is only 0.333%. The accuracy of the developed equation has been compared to that of Antoine and other mostly used equations. Our comparisons show that new equation leads to more accurate results than those of literature methods.
https://www.physchemres.org/article_10448_8e69c2ef0a287b8708a90aa4a5f27522.pdf
2015-12-01
279
291
10.22036/pcr.2015.10448
vapor pressure
C-H-O
Pure compounds
Correlation
Antoine
Mehdi
Reiszadeh
reiszadeh@iaush.ac.ir
1
Chemical Engineering Department, Shahreza Branch, Islamic Azad University, Shahreza, Iran
AUTHOR
Ehsan
Sanjari
sanjary@gmail.com
2
Mechanical Engineering Department, Najafabad Branch, Islamic Azad University, Isfahan, Iran
LEAD_AUTHOR
Zahra
Jali
zahrajaly19861364@gmail.com
3
Chemical Engineering Department, Shahreza Branch, Islamic Azad University, Shahreza, Iran
AUTHOR
Mohammad
Saviz Baktash
msbaktash@gmail.com
4
Chemical Engineering Department, Shahreza Branch, Islamic Azad University, Shahreza, Iran
AUTHOR
ORIGINAL_ARTICLE
Fabrication and Characterization of Rutile TiO2 Nanocrystals by Water Soluble Precursor
In this research, TiO2 nanoparticles were synthesized by a simple wet chemical method. TiCl4 was used as precursor in hydrogen peroxideand ethanol. The TiO2 nanoparticles were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), electron dispersive spectroscopy (EDS) and UV-Vis spectrophotometer. The particle size of the as-synthesized TiO2 was estimated by XRD and TEM analyses in the range of 5-10 nm. The SEM images showed that the size of sphere-like shaped nanoparticles decrease with increasing annealing temperature. The prepared TiO2 nanoparticles were characterized for phase composition, using X-ray diffractometry. The crystal structure of the nanoparticles after annealing was measured by XRD analysis. It was realized that phase transition from anatase to rutile occurs after heat treatment at 600 °C. The particle size of the annealed sample was also calculated about 20 nm by XRD analysis. The EDS spectrum showed peaks of titanium and oxygen with fewer impurities. The UV-Vis spectrum showed anatase and rutile phase at wavelength about 375 nm (Eg = 3.30 eV) and 470 nm (Eg = 2.63 eV) for as-prepared TiO2 and annealed TiO2 nanoparticles respectively.
https://www.physchemres.org/article_10641_769690183772824fd8c313c16bc1dc29.pdf
2015-12-01
293
298
10.22036/pcr.2015.10641
TiO2 nanocrystals
Wet chemical
Anatase
Phase transition
Rutile
Majid
Farahmandjou
farahmand_ph@yahoo.com
1
Department of Physics, Varamin Pishva Branch, Islamis Azad University, Varamin, Iran
LEAD_AUTHOR
ORIGINAL_ARTICLE
Effect of Defects on Mechanical Properties of Graphene under Shear Loading Using Molecular Dynamic Simulation
Graphene sheet including single vacancy, double vacancy and Stone-Wales with armchair and zigzag structure was simulated using molecular dynamics simulation. The effect of defects on shear’s modulus, shear strength and fracture strain was investigated. Results showed that these shear properties reduce when the degrees of all kinds of defects increase. The dangling bond in SV and DV defected graphene leads to decrease its mechanical properties especially shear strength and fracture strain where the role of weak interatomic bonds are important. The vacancies in DV defected graphene are also next to each other and slide over each other under shear deformation results to less shear strength than that of SV defected graphene. Results can be useful in tuning the mechanical properties of graphene-based materials that is a key-role parameter in designing and fabrication of nanomechanical systems. However, the maximum and minimum reduction occurs for single vacancy and Stone-Wales defects, respectively. It was also found that distinction between shear properties of zigzag and armchair structures is preserved in defected graphene.
https://www.physchemres.org/article_10716_3640171fc02e47b5975e8fb9719d9c91.pdf
2015-12-01
299
304
10.22036/pcr.2015.10716
graphene
Simulation
Shear’s modulus
Defect
Salimeh
Kimiagar
s.kimia8579@gmail.com
1
Islamic Azad University- central Tehran Branch - Tehran - Iran
LEAD_AUTHOR
Ali
Rajabpour
a.rajabpour@gmail.com
2
Mech. Eng., Imam Khomeini International University, Qazvin
AUTHOR
Fatemeh
Tavazoee
tavazoee.f@gmail.com
3
Islamic Azad University, Central Tehran Branch, Physics department, Tehran.
AUTHOR
ORIGINAL_ARTICLE
Determination and Modeling of Activity Coefficients of Sodium Chloride in (Glycerol + Water) Mixtures Based on Potentiometric Measurements
In this work, the results concerning to the mean activity coefficient measurements for NaCl in the (glycerol + water) system using the potentiometric method are reported. The potentiometric measurements were performed on the galvanic cells without liquid junction of the type: Ag|AgCl|NaCl (m), glycerol (wt%), H2O (1 - wt)%|Na-ISE, in various mixed solvent systems containing 0, 5, 10, 20 and 30 mass fraction percents of glycerol over ionic strength ranging from 0.0020-3 mol kg-1 at T = 298.2 K. The sodium ion selective electrode and Ag-AgCl electrode as self-made electrodes had a reasonably Nernst response. The modified zeolite was used to fabricate the sodium ion selective electrode as electrochemical sensor. The modeling of the investigated system was made based on an extended Debye-Hückel equation, the Pitzer and Pitzer-Simonson-Clegg models. The unknown parameters were determined for each model. The resulting values of the mean activity coefficients, osmotic coefficients and excess Gibbs energy are reported for the studied system.
https://www.physchemres.org/article_10862_c3ee6f090057cf7b7cd1ebc4b57822b9.pdf
2015-12-01
305
318
10.22036/pcr.2015.10862
Activity coefficient
Potentiometry
NaCl
Glycerol
Pitzer model
Maryam
Hosseini
hosseynimaryam@ymail.com
1
University of Guilan
AUTHOR
Bahram
Ghalami-Choobar
b.ghalami@gmail.com
2
University of Guilan
LEAD_AUTHOR
Mohammad Ali
Zanjanchi
zanjanchi@guilan.ac.ir
3
University of Guilan
AUTHOR
ORIGINAL_ARTICLE
Biological Applications of Isothermal Titration Calorimetry
Most of the biological phenomena are influenced by intermolecular recognition and interaction. Thus, understanding the thermodynamics of biomacromolecule ligand interaction is a very interesting area in biochemistry and biotechnology. One of the most powerful techniques to obtain precise information about the energetics of (bio) molecules binding to other biological macromolecules is isothermal titration calorimetry (ITC). In a typical ITC experiment, a macromolecule solution is titrated by a solution containing a reactant at a constant temperature, and exchanged heat of the reaction is measured, allowing determination of thermodynamic parameters (enthalpy change, entropy change, change in Gibbs free energy, binding affinity and stoichiometry) of molecular interactions. In this review article, we describe the ITC approach briefly and review some applications of ITC for studying protein-ligand interactions, protein-protein interactions, self-association, and drug design processes. Furthermore, the application of ITC for determination of kinetic parameters of enzyme catalyzed reactions as well as thermodynamic parameters will be discussed.
https://www.physchemres.org/article_11066_9c29ae4d27dcf425d85bb2530721bd4b.pdf
2015-12-01
319
330
10.22036/pcr.2015.11066
Isothermal titration calorimetry
Ligand binding
Enthalpy of binding
Drug design
Enzyme kinetics
Maliheh Sadat
Atri
m.atri@umz.ac.ir
1
Department of Molecular and Cell Biology, Faculty of Basic Sciences, University of Mazandaran, Babolsar, Iran
LEAD_AUTHOR
Ali Akbar
Saboury
saboury@ut.ac.ir
2
Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran. Center of Excellence in Biothermodynamics, University of Tehran, Tehran, Iran.
AUTHOR
Faizan
Ahmad
faizan.ahmad.jmi@gmail.com
3
Centre for Interdisciplinary Research in Basic Sciences, JamiaMilliaIslamia (A Central University), Jamia Nagar, NEW DELHI - 110 025, India
AUTHOR
ORIGINAL_ARTICLE
Influence of Different Percentages of Copper on the Size and Optical Properties of Ag-Cu Nanoparticles Formed by Wet-Chemical Method
In this work, Ag-Cu nanoparticles (with different percentages of copper, 10%, 25%, 50%, 75% Cu) were synthesized by wet chemical method. Copper(II) sulfate and silver nitrate were taken as metal precursors, ascorbic acid as reducing agent and anhydride maleic (MA) as a modifier. The prepared nanoparticles were characterized by means of X-ray diffraction (XRD) technique and scanning electron microscopy (SEM-EDAX), Fourier transform infrared spectroscopy (FT-IR) and UV-Vis spectroscopy. SEM indicated the formation of uniform spherical crystalline nanoparticle in a well distributed size and morphology. It can be seen from these pictures that the particle size decreased with increasing of the copper percent. When the molar ratio of Cu2+/Ag+ is 75/25 (>50%), mixture of the spherical and hexagonal nanoparticles was prepared. Three pronounced Ag diffraction peaks (111), (200) and (220) appeared at 2θ = 38°, 43.9° and 64.1°, respectively. The three most intense peaks of the XRD pattern of sample showed a slight shifting of the center of the diffraction peaks toward a lower angle. No shifting was observed in XRD lines with the increase of Cu2+ to Ag+ ratio in the Cu2+/Ag+ mixed solution (> 50% Cu). Fourier transform infrared spectroscopy (FT-IR) showed that nanoparticles are coordination between oxygen atoms and nanoparticles, because functional unit C=O present in MA, shifts to 1652.69 cm-1 after embedding nanoparticles. The position of the surface plasmon resonance (SPR) absorption band on the nanoparticles could be shifted from 380-350 nm via the change of their percentage of Cu.
https://www.physchemres.org/article_11124_f04a4fdbb6d4d337b96652bcf4d4c6a2.pdf
2015-12-01
331
339
10.22036/pcr.2015.11124
Different percentages of copper
Control size
Copper-silver
Wet-chemical method
Optical properties
Parivash
Mashayekhishams
prmashayekhi@gmail.com
1
Department of chemistry, Science and Research branch, Islamic Azad university, Tehran, Iran.
LEAD_AUTHOR
Alireza
Banaei
alireza.banaei@gmail.com
2
Payame Noor university, Tehran, Iran.
AUTHOR
ORIGINAL_ARTICLE
How to Change the Redox Potential of Guanine?
Due to some important applications of guanine electrode in scientific and technology research such as electro-chemical DNA based biosensors, and a problem of high redox potential of guanine (0.81 V), our research study concentrates on reducing guanine redox potential by substituting Cu, Ag, Au, CH3, C2H5 and Cl on sites of 1, 2 and 9 of guanine. A 5.0% reduction of redox potential for 9-Ag-guanine was the sign of favorable result. In order to have further lower potential, sliver clusters (Ag2 andAg3) were used. The obtained percentages of reduction of potentials were 53.6% and 36.8% for 9-Ag2 and 9-Ag3-guanine, respectively. In this research, Gaussian 09 was used and DFT was applied with long-range corrected xc-functional (LC-BLYP).
https://www.physchemres.org/article_11247_2b97abdcfa14429753dcbc12026e9995.pdf
2015-12-01
341
346
10.22036/pcr.2015.11247
Redox Potentials
Guanine
Substitutions
Biosensor
Ali
Pakiari
pakiariah@gmail.com
1
Shiraz University
LEAD_AUTHOR
Elham
Dehghanpisheh
e-dehghanpisheh@gmail.com
2
Shiraz University, Chemistry Department.
AUTHOR
Behzad
Haghighi
bhaghighi@shirazu.ac.ir
3
Chemistry Dept. Shiraz University
AUTHOR
ORIGINAL_ARTICLE
A Hard Convex Core Yukawa Equation of State for Nonassociated Chain Molecules
The compressibility factor of nonassociated chain molecules composed of hard convex core Yukawa segments was derived with SAFT-VR and an extension of the Barker-Henderson perturbation theory for convex bodies. The temperature-dependent chain and dispersion compressibility factors were derived using the Yukawa potential. The effects of temperature, packing fraction, and segment number on the compressibility factor were investigated for chains of the prolate sphereocylinder segments. A comparison of hard core Yukawa chain compressibility factor values and hard chain compressibility factor values showed that the type of interaction potential has more effect on those chain molecules with higher segment numbers. The results demonstrated that in reduced temperatures 1.4 and 2.4, the Yukawa chain of the compressibility factor is insensitive to temperature, while the dispersion term of the compressibility factor changes remarkably with the temperature. The derived equation of state can fairly predict the SAFT-VR results of the hard sphere core chain molecules in the limit of α = 1.
https://www.physchemres.org/article_11597_f8c6ca55c0c2e9239e0b8951aa3f72ca.pdf
2015-12-01
347
360
10.22036/pcr.2015.11597
Convex body
Chain molecule
Perturbation theory
SAFT-VR
Yukawa potential
Nahid
Farzi
nfarzi@sci.ui.ac.ir
1
physical chemistry
LEAD_AUTHOR
Zeinab
Yaghoubi
yaghobizainab@ymail.com
2
Department of chemistry, university of Isfahan,Iran
AUTHOR