Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 24 of 24

Full-Text Articles in Physical Sciences and Mathematics

Dft Modeling Of Water-Assisted Hydrogen Peroxide Formation From A C(4a)-(Hydro)Peroxyflavin, Yilmaz Özkiliç Jun 2024

Dft Modeling Of Water-Assisted Hydrogen Peroxide Formation From A C(4a)-(Hydro)Peroxyflavin, Yilmaz Özkiliç

Turkish Journal of Chemistry

The cofactor of a class A monooxygenase is reduced at an external location of the enzyme and is subsequently pulled back into the active site after the reduction. This observation brings the question; is there any defense mechanism of the active site of a monooxygenase against the formation of the harmful hydrogen peroxide from the reactive C(4a)-(hydro)peroxide intermediate? In this study, the barrier energies of one to three water molecule-mediated uncoupling reaction mechanisms in water exposed reaction conditions were determined. These were found to be facile barriers. Secondly, uncoupling was modeled in the active site of kynurenine 3-monooxygenase complex which …


Theoretical Analysis Of Oled Performances Of Some Aromatic Nitrogen-Containing Ligands, Mustafa Eli̇k Aug 2023

Theoretical Analysis Of Oled Performances Of Some Aromatic Nitrogen-Containing Ligands, Mustafa Eli̇k

Turkish Journal of Chemistry

It is well-known that tris(8-hydroxyquinoline) aluminum (Alq3) complex and N,N'diphenyl-N,N'-bis(3-methylphenyl)-1,1'- diphenyl-4,4'-diamine compound (TPD) are widely used as electron transfer material (ETL) and hole transfer material (HTL) in organic light emitting diode (OLED) structure, respectively. Considering the reference materials, in the present work, the OLED performances of some cyclic aromatic structures such as 4,4'azopyridine [AZPY], 4,4'-bipyridine [BIPY], 1,2-bis[4'-(4-methylphenyl)2,2':6'2' '-terpyridin6-yl]ethyne (BISTERPY), 5,5'-diamino-2,2'-bipyridine (DABP), dipyrido[3,2-a:2',3'c]phenazine (DPP), 4,7-phenanthroline (PHEN) including nitrogen atom have been theoretically analyzed. It is important to note that B3LYP/6-31G(d) and B3LYP/TZP levels of the theory were taken into account for the calculations about monomeric and dimeric structures, respectively. Additionally, the …


An Experimental And Theoretical Analysis Of Supercritical Carbon Dioxide Extraction Of Cu(Ii) And Pb(Ii) Ions In The Form Of Dithizone Bidentate Complexes, Jeton Halili, Avni Berisha Jan 2022

An Experimental And Theoretical Analysis Of Supercritical Carbon Dioxide Extraction Of Cu(Ii) And Pb(Ii) Ions In The Form Of Dithizone Bidentate Complexes, Jeton Halili, Avni Berisha

Turkish Journal of Chemistry

For more than five decades, dithizone has been widely used as an analytical reagent. This ligand forms strongly colored complexes with metal ions and this ability to form complexes can be used for extraction/removal of certain metal ions in addition to analytical determination. In static mode, the supercritical carbon dioxide extraction of copper and lead ions from aqueous solutions after complexation by the dithizone ligand is studied (at two different conditions: a) p = 120 bar, T = 30 °C, and b) p = 72 bar, T = 50 °C). The addition of methanol improved the extraction process by modulating …


Dissolution Of Alumina In Cryolite Melts: A Conceptual Dft Study, Ali̇met Sema Özen, Zehra Akdeni̇z Jan 2022

Dissolution Of Alumina In Cryolite Melts: A Conceptual Dft Study, Ali̇met Sema Özen, Zehra Akdeni̇z

Turkish Journal of Physics

Interactions between alumina and cryolite clusters were investigated using chemical reactivity descriptors based on Conceptual DFT such as global hardness, $\eta$, global softness, $S$, fukui functions, $f$, and local softness, $s$. Hard and Soft Acids and Bases (HSAB) Principle was applied for identifying clusters that are most likely to interact with alumina, Al$_2$O$_3$. Local reactivity descriptors were employed to predict the most probable regions of interaction within the cluster.


A Theoretical Study Of Co Adsorption On Cu(211) Surface With Coverage Effects, Murat Oluş Özbek Jan 2022

A Theoretical Study Of Co Adsorption On Cu(211) Surface With Coverage Effects, Murat Oluş Özbek

Turkish Journal of Chemistry

CO adsorption on the Cu(211) surface was investigated using energy, geometry and vibrational data, which were produced through periodic DFT computations. Adsorption on the (111) terrace, as well as the previously reported top and bridge sites of the step-edges, was studied at 0.25, 0.33, 0.50, 0.66, 0.75, and 1.00 monolayer (ML) CO coverage. Results showed that up to and including 0.50 ML, on-top or bridge adsorption is preferred on the step-edges. When 0.50 ML is exceeded, top-bridge alternating patterns become feasible on the step edges along with possible shifts towards the terrace. Several feasible patterns were identified at 0.66, 0.75, …


A Study Of Silicon And Germanium-Based Molecules In Terms Of Solar Cell Devices Performance, Emi̇ne Taniş Jan 2022

A Study Of Silicon And Germanium-Based Molecules In Terms Of Solar Cell Devices Performance, Emi̇ne Taniş

Turkish Journal of Chemistry

Photovoltaic energy sources are increasingly in demand due to the cost of petroleum fuels and concerns about carbon emissions. For this reason, it is important to determine the photovoltaic properties of the compounds that are thought to be suitable for these energy sources. Here, 1,1,2,3,4,5-Hexaphenyl-1H-silole (HPS) and 1,1,2,3,4,5-Hexaphenyl-1H-germole (HPG) compounds that are thought to have excellent photovoltaic properties, electronic and charge transport properties were investigated experimentally and theoretically. The total energies, absorption spectra, Fermi energy (Efl) and work function (φ), maximum open circuit voltage (VOC), reorganization energies (λe and λh), frontier molecular orbital …


Theoretical Investigation Of The Interaction Between The Metal Phthalocyanine [Mpc] A(M = Sc, Ti, And V; A = ?1, 0, And +1) Complexes And Formaldehyde, Nasim Hassani Jan 2021

Theoretical Investigation Of The Interaction Between The Metal Phthalocyanine [Mpc] A(M = Sc, Ti, And V; A = ?1, 0, And +1) Complexes And Formaldehyde, Nasim Hassani

Turkish Journal of Chemistry

Formaldehyde (FA, CH2O) is one of the toxic volatile organic compounds that cause harmful effects on the human body. In this work, the interaction of FA gas with metal phthalocyanine (MPc) molecules was studied by employing density functional theory calculations. A variety of [MPc] a (M = Sc, Ti, and V; a = -1, 0, and +1) complexes were studied, and the electronic properties, interaction energies, and charge transfer properties of all of the studied molecules were systematically discussed. Among the studied complexes, the Sc and Ti phthalocyanines were more reactive toward the adsorption of FA gas. Moreover, it was …


Fluorescent Sensing Platform For Low-Cost Detection Of Cu$^{\Mathbf{2+}}$ By Coumarin Derivative: Dft Calculation And Practical Application In Herbal And Black Tea Samples, Tahi̇r Savran, Abdurrahman Karagöz, Şükri̇ye Ni̇han Karuk Elmas, Duygu Aydin, Furkan Özen, Kenan Koran, Fatma Nur Arslan, Ahmet Orhan Görgülü, İbrahi̇m Yilmaz Jan 2020

Fluorescent Sensing Platform For Low-Cost Detection Of Cu$^{\Mathbf{2+}}$ By Coumarin Derivative: Dft Calculation And Practical Application In Herbal And Black Tea Samples, Tahi̇r Savran, Abdurrahman Karagöz, Şükri̇ye Ni̇han Karuk Elmas, Duygu Aydin, Furkan Özen, Kenan Koran, Fatma Nur Arslan, Ahmet Orhan Görgülü, İbrahi̇m Yilmaz

Turkish Journal of Chemistry

A fluorogenic probe based on a coumarin-derivative for Cu$^{2+}$ sensing in CH$_{3}$CN/H$_{2}$O media (v/v, 95/5, 5.0 \textmu M) was developed and applied in real samples. 3-(4-chlorophenyl)-6,7-dihydroxy-coumarin (MCPC) probe was obtained by synthetic methodologies and identified by spectral techniques. The probe MCPC showed remarkable changes with a ``turn-off'' fluorogenic sensing approach for the monitoring of Cu$^{2+}$ at 456 nm under an excitation wavelength of 366 nm. The response time of the probe MCPC was founded as only 1 min. The detection limit of the probe MCPC was recorded to be 1.47 nM. The binding constant and possible stoichiometric ratio (1:1) values …


Design Of Novel Substituted Phthalocyanines; Synthesis And Fluorescence, Dft,Photovoltaic Properties, Mehmet Sali̇h Ağirtaş, Derya Güngördü Solğun, Ümi̇t Yildiko, Abdullah Özkartal Jan 2020

Design Of Novel Substituted Phthalocyanines; Synthesis And Fluorescence, Dft,Photovoltaic Properties, Mehmet Sali̇h Ağirtaş, Derya Güngördü Solğun, Ümi̇t Yildiko, Abdullah Özkartal

Turkish Journal of Chemistry

The 4-(2-[3,4-dimethoxyphenoxy] phenoxy) phthalonitrile was synthesized as the starting material of new syntheses. Zinc, copper, and cobalt phthalocyanines were achieved by reaction of starting compound with Zn(CH3COO)2, CuCl2, and CoCl2 metal salts. Basic spectroscopic methods such as nuclear magnetic resonance electronic absorption, mass and infrared spectrometry were used in the structural characterization of the compounds. Absorption, excitation, and emission measurements of the fluorescence zinc phthalocyanine compound were also investigated in THF. Then, structural, energy, and electronic properties for synthesized metallophthalocyanines were determined by quantum chemical calculations, including the DFT method. The bandgap of HOMO and LUMO was determined to be …


Synthesis, Optical, And Structural Properties Of Bisphenol-Bridgedaromatic Cyclic Phosphazenes, Bünyemi̇n Çoşut, Burcu Topaloğlu Aksoy, Süreyya Oğuz Tümay, Ahmet Şenocak, Serkan Yeşi̇lot Jan 2020

Synthesis, Optical, And Structural Properties Of Bisphenol-Bridgedaromatic Cyclic Phosphazenes, Bünyemi̇n Çoşut, Burcu Topaloğlu Aksoy, Süreyya Oğuz Tümay, Ahmet Şenocak, Serkan Yeşi̇lot

Turkish Journal of Chemistry

Phenoxy- and naphthoxy-substituted bisphenol-bridged cyclic phosphazenes were synthesized in 2 steps and their thermal, photophysical, and electrochemical properties were investigated. The structures of the cyclic phosphazene compounds were determined by ESI-MS mass spectrometry and $^{1}$H, $^{13}$C, and $^{31}$P NMR spectroscopies. The photophysical studies of phenoxy- and naphthoxy-substituted bridged cyclophosphazenes were investigated by means of absorption and fluorescence spectroscopies in different solvents. Thermal and electrochemical properties of the target compounds were also studied. Furthermore, the excimer emissions through intramolecular interactions in solution and in solid state were investigated by fluorescence spectroscopy and the theoretical calculations were performed in detail using DFT.


A Theoretical Investigation On The Activation Of Small Molecules By A Disilenide: A Dft Prediction, Cem Burak Yildiz, Akin Azi̇zoğlu Jan 2019

A Theoretical Investigation On The Activation Of Small Molecules By A Disilenide: A Dft Prediction, Cem Burak Yildiz, Akin Azi̇zoğlu

Turkish Journal of Chemistry

Herein, we proposed several mechanistic scenarios for activation of small molecules (NH$_{3}$, CO$_{2}$, CS$_{2}$, H$_{2}$, CH$_{4}$, N$_{2}$, and N$_{2}$O) by a disilicon analogue of a vinyl anion (1H) using density functional theory (DFT) calculations. The DFT results established that all the possible reactions to yield a variety of potential products have an exergonic nature except for the activation of N$_{2}$ with the obtained overall energy of $\Delta $G = 33.6 kcal mol$^{-1}$. Moreover, the highest exergonic character was $\Delta $G = $-$95.8 kcal mol$^{-1}$ for N$_{2}$O. Therefore, the findings reveal that 1H can be considered a suitable candidate for activation …


Density Functional Theory Of Cubic Zirconia And 6-15 Mol% Doped Yttria-Stabilized Zirconia: Structural And Mechanical Properties, Berna Akgenç, Tahi̇r Çağin Jan 2018

Density Functional Theory Of Cubic Zirconia And 6-15 Mol% Doped Yttria-Stabilized Zirconia: Structural And Mechanical Properties, Berna Akgenç, Tahi̇r Çağin

Turkish Journal of Physics

Results of ab-initio density-functional theory calculations within the generalized gradient approximation (GGA-PBE) of structural and mechanical properties of cubic zirconia and yttria-stabilized zirconia (YSZ) with yttria (Y$_{2}$O$_{3})$ concentrations of 6.67, 10.34, and 14.28 mol% are reported. It is found that the calculated structural and mechanical parameters of all considered structures are highly consistent with the existing experimental data and the other theoretical values. The doping concentration of yttria-stabilized zirconia has critical importance in ionic conductivity and stabilization of high temperature down to room temperature. The lattice parameter and cell volume linearly decrease with increases in doping concentration. Moreover, the effects …


Density Functional Study Of The Structure And Water Adsorption Activity Of An Al$_{30}$O$_{30}$ Star-Shaped Alumina Nanocage, Mehdi Zamani Jan 2016

Density Functional Study Of The Structure And Water Adsorption Activity Of An Al$_{30}$O$_{30}$ Star-Shaped Alumina Nanocage, Mehdi Zamani

Turkish Journal of Chemistry

Molecular and electronic structures of a novel Al$_{30}$O$_{30}$ star-shaped alumina nanocage (SANC) were studied using the recently developed CAM-B3LYP density functional method. Comparison of the stretching vibrational modes of this compound with the corresponding modes related to an Al$_{20}$O$_{30}$ perfect cage and Al$_{50}$O$_{75}$ tubular alumina nanomaterials showed a shift to lower frequencies, while the bending modes moved to higher frequencies. The highest occupied molecular orbital (HOMO) of the SANC had 65% nonbonding character, whereas the lowest unoccupied molecular orbital (LUMO) was 72% antibonding. The HOMO and LUMO of the SANC arose mostly from Al 3s and 2p atomic orbitals. The …


Experimental And Theoretical Investigation Of The Reaction Between Co$_{2}$ And Carbon Dioxide Binding Organic Liquids, Hi̇lal Tankal, Özge Yüksel Orhan, Erdoğan Alper, Telhat Özdoğan, Hakan Kayi Jan 2016

Experimental And Theoretical Investigation Of The Reaction Between Co$_{2}$ And Carbon Dioxide Binding Organic Liquids, Hi̇lal Tankal, Özge Yüksel Orhan, Erdoğan Alper, Telhat Özdoğan, Hakan Kayi

Turkish Journal of Chemistry

The reaction kinetics of CO$_{2}$ absorption into new carbon dioxide binding organic liquids (CO$_{2}$BOLs) was comprehensively studied to evaluate their potential for CO$_{2}$ removal. A stopped-flow apparatus with conductivity detection was used to determine the CO$_{2}$ absorption kinetics of novel CO$_{2}$BOLs composed of DBN (1,5-diazabicyclo[4.3.0]non-5-ene)/1-propanol and TBD (1,5,7-triazabicyclo[4.4.0]dec-5-ene)/1-butanol. A modified termolecular reaction mechanism for the reaction of CO$_{2}$ with CO$_{2}$BOLs was used to calculate the observed pseudo-first-order rate constant k$_{0}$ (s$^{-1})$ and second-order reaction rate constant k$_{2}$ (m$^{3}$/kmol.s). Experiments were performed by varying organic base (DBN or TBD) weight percentage in alcohol medium for a temperature range of 288-308 K. …


A Computational Study On The Interaction Between O$_{2}$ And Pristine And Ge-Doped Aluminum Phosphide Nanotubes, Mahdi Rezaei Sameti, Alireza Kazemi Jan 2015

A Computational Study On The Interaction Between O$_{2}$ And Pristine And Ge-Doped Aluminum Phosphide Nanotubes, Mahdi Rezaei Sameti, Alireza Kazemi

Turkish Journal of Physics

In this research the interaction between oxygen molecules and the outside and inside surfaces of pristine and Ge-doped (4,4) armchair and (6,0) zigzag models of aluminum phosphide nanotubes (AlPNTs) was systematically investigated using density function theory. Structural parameters, adsorption energy, quantum parameters, HOMO/LUMO orbitals, and nuclear quadrupole resonance (NQR) parameters were calculated for all models of AlPNTs. The aim of this work was to investigate the effects of Ge doping and O$_{2}$ adsorption on the electrical and structural parameters of (4,4) armchair and (8,0) zigzag models of AlPNTs. The results revealed that adsorption energies for all models were negative with …


Theoretical Investigations Of Pt_3x (X = Al, Sc, Hf, Zr) Ground State, Adewumi Isaac Popoola, Lesley Heath Chown, Lesley Alison Cornish Jan 2014

Theoretical Investigations Of Pt_3x (X = Al, Sc, Hf, Zr) Ground State, Adewumi Isaac Popoola, Lesley Heath Chown, Lesley Alison Cornish

Turkish Journal of Physics

The electronic structure of Pt_3X compounds showed that Pt_3Hf and Pt_3Zr were more stable for the D0_{24} structure, rather than L1_2. The compound Pt_3Al was predicted to be the hardest and most ductile, but not with the L1_2 structure at ground state. The density of states showed that Pt_3Hf, Pt_3Zr, and Pt_3Al can be stabilized to the L1_2 phase with suitable element addition. All calculations were done within the density functional theory framework.


Nature Of Second-Order Nonlinear Optical Response In Phthalocyanine Derivatives: A Density Functional Theory Study, Chiming Wang, Chao Chen, Qingqi Zhang, Dongdong Qi, Jianzhuang Jiang Jan 2014

Nature Of Second-Order Nonlinear Optical Response In Phthalocyanine Derivatives: A Density Functional Theory Study, Chiming Wang, Chao Chen, Qingqi Zhang, Dongdong Qi, Jianzhuang Jiang

Turkish Journal of Chemistry

Density functional theory was employed to investigate a series of phthalocyanine derivatives, discovering the limitation when the expansion of the conjugated system was employed to improve the hyper-Rayleigh scattering response coefficient. Furthermore, an unusually C_{\infty v}-type octupolar population was found by electrostatic potential analysis. In addition, the dynamic and static hyper-Rayleigh scattering responses (\beta_{HRS}) were simulated using the coupled perturbed density functional theory, showing an increasing dynamic \beta_{HRS} value along with an increase in incident light energy.


A Combined First Principles Tddft And Experimental Study On The Uv-Vis Spectra Properties Of M(P-Nitrophenyl Azo Resorcinol)_3 Complexes (M: Fe, Cr), Tuğba Ari̇fi̇oğlu, Meli̇s Efeçinar, Nuray Şatiroğlu Jan 2014

A Combined First Principles Tddft And Experimental Study On The Uv-Vis Spectra Properties Of M(P-Nitrophenyl Azo Resorcinol)_3 Complexes (M: Fe, Cr), Tuğba Ari̇fi̇oğlu, Meli̇s Efeçinar, Nuray Şatiroğlu

Turkish Journal of Chemistry

UV-Vis absorption data of p-nitrophenyl azo resorcinol (Magneson I) and its 2 Fe(III) and Cr(III) complexes were investigated both experimentally and theoretically. The geometries were optimized at BP86/TZVP level. The most stable spin states were computed as doublet and quartet for Fe(magneson)_3 and Cr(magneson)_3 complexes, respectively. Time-dependent density functional theory (TDDFT) was employed to explore the absorption spectra properties, whereas the solvent effects were taken into account using the polarizable continuum model (PCM). The M06, B3LYP, and PBE0 hybrid functionals together with TZVP/LANL2TZ basis sets were used for comparing the results with experimental data. The theoretical analysis of electronic structure …


Synthesis, Characterization, And Dft Calculation Of A Pd(Ii) Schiff Base Complex, Alireza Akbari, Zahra Alinia Jan 2013

Synthesis, Characterization, And Dft Calculation Of A Pd(Ii) Schiff Base Complex, Alireza Akbari, Zahra Alinia

Turkish Journal of Chemistry

The 4-((E)-(2-((E)-2, 4-dihydroxybenzylideneamino) ethylimino) methyl) benzene-1,3-diol tetradentate ligand, H_2L, reacted with PdCl_2 to produce the related complex. The complex was characterized by elemental analysis, infrared and electronic spectroscopy, thermogravimetric study, and molar conductance. Furthermore, the fully optimized geometries were calculated using the ADF 2009.01 package. Comparison between the calculated and experimental results covering molecular structures, assignment of fundamental vibrational modes, and thermodynamic properties were investigated. The optimized molecular geometries were compared with the experimental data obtained from X-ray data of a similar complex, which indicated that the theoretical results agree with the corresponding experimental values. The UV-Vis spectrum of the …


Ni_{55} Nanocluster: A Density Functional Theory Study Of The Binding Energy Of Nickel And Ethylene Adsorption, Nusret Duygu Yilmazer, Mehmet Ferdi̇ Fellah, Işik Önal Jan 2012

Ni_{55} Nanocluster: A Density Functional Theory Study Of The Binding Energy Of Nickel And Ethylene Adsorption, Nusret Duygu Yilmazer, Mehmet Ferdi̇ Fellah, Işik Önal

Turkish Journal of Chemistry

Ethylene adsorption on a Ni_{55} nanocluster was studied by means of the density functional theory (DFT)/B3LYP using the basis sets of 6-31G(d,p) and 86-411(41d)G in Gaussian 03. The Ni_{55} nanocluster was found to have a distorted icosahedral geometry, in accordance with the experimental findings. The binding energy value for the Ni_{55} nanocluster was calculated to be 3.51 eV/atom using equilibrium geometry calculations. The estimated bulk nickel binding energy was in reasonable agreement with the experimental value (4.85 versus 4.45 eV/atom). In addition, equilibrium geometry calculations were performed for ethylene adsorption on the Ni_{55} nanocluster for 2 different coordination numbers of …


E)--2--Acetyl--4--(4--Methoxyphenyldiazenyl) Phenol: X--Ray And Dft--Calculated Structure, Serap Yazici, Çi̇ğdem Albayrak, İsmai̇l Erdem Gümrükçüoğlu, İsmet Şenel, Orhan Büyükgüngör Jan 2011

E)--2--Acetyl--4--(4--Methoxyphenyldiazenyl) Phenol: X--Ray And Dft--Calculated Structure, Serap Yazici, Çi̇ğdem Albayrak, İsmai̇l Erdem Gümrükçüoğlu, İsmet Şenel, Orhan Büyükgüngör

Turkish Journal of Chemistry

The crystal structure of the title compound, (E)-2-acetyl-4-(4-methoxyphenyldiazenyl) phenol, displays a trans configuration of the azo moiety as found for other azo (diazene) derivatives. The aromatic mean planes are nearly coplanar and the dihedral angle between the 2 aromatic rings is 3.04(8)°. The molecules, with strong intramolecular O--H...O hydrogen bonding, are linked by weak van der Waals interactions in the 3-dimensional network. The molecular geometry, determined using X-ray diffraction techniques, was also calculated with the density functional theory (DFT), employing the hybrid exchange-correlation functional B3LYP. Experimental and theoretical IR spectra of the compound were also calculated for comparison. The results …


A Density Functional Theory Study Of Oxidation Of Benzene To Phenol By N_2o On Fe- And Co-Zsm-5 Clusters, Mehmet Ferdi̇ Fellah, Işik Önal Jan 2009

A Density Functional Theory Study Of Oxidation Of Benzene To Phenol By N_2o On Fe- And Co-Zsm-5 Clusters, Mehmet Ferdi̇ Fellah, Işik Önal

Turkish Journal of Chemistry

Density functional theory (DFT) calculations were carried out in the study of oxidation of benzene to phenol by N_2O on relaxed [(SiH_3)_4AlO_4M] (where M=Fe, Co) cluster models representing Fe- and Co-ZSM-5 surfaces. The catalytic cycle steps are completed for both Fe-ZSM-5 and Co-ZSM-5 clusters. The general trend of the results that were obtained in terms of activation barriers for the Fe-ZSM-5 cluster is in agreement with the experimental and theoretical literature. It was observed that the phenol formation step is the rate-limiting step for both clusters and Co-ZSM-5 surface has a lower activation barrier than the Fe-ZSM-5 surface (i.e. 35.82 …


Activation Of Light Alkanes On Pure And Fe And Al Doped Silica Clusters: A Density Functional And Oniom Study, Mehmet Ferdi̇ Fellah, Işik Önal Jan 2007

Activation Of Light Alkanes On Pure And Fe And Al Doped Silica Clusters: A Density Functional And Oniom Study, Mehmet Ferdi̇ Fellah, Işik Önal

Turkish Journal of Chemistry

C-H bond activation was studied by use of density functional theory (DFT) and ONIOM calculations as implemented in Gaussian 2003 at the B3LYP level utilising 6-31G* as the basis set for Si, Al, and Fe atoms and 3-21G** as the basis set for O and H atoms. Relative energy profiles were determined for pure silica modeled by a Si_7O_{21} cluster and Fe and Al doped silica clusters via coordinate driving calculations. The activation barriers for C-H bond activation of methane and ethane decrease with the substitution of Fe on the silica surface, which theoretically demonstrates a favorable effect of Fe …


A Labview-Based Virtual Instrument For Engineering Education: A Numerical Fourier Transform Tool, Levent Sevgi̇, Çağatay Uluişik Jan 2006

A Labview-Based Virtual Instrument For Engineering Education: A Numerical Fourier Transform Tool, Levent Sevgi̇, Çağatay Uluişik

Turkish Journal of Electrical Engineering and Computer Sciences

Engineering is based on practice. The minima of this practice should be given during the university education. This has become more and more comprehensive and expensive parallel to high-technology devices developed and presented to societies. Computers, microprocessor-based devices, programmable systems on Chip (PSoC), etc., make engineering education not only very complex but interdisciplinary as well. Building undergraduate labs has become more and more expensive if only physical experimentation and hands-on training are targeted. On the other hand, simple, comparatively much cheaper software may turn a regular personal computer (PC) into a virtual lab. The key question therefore is, to establish …