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61.
Muhammad Javed Iqbal Zahoor Ahmad Turgut Meydan Yevgen Melikhov 《Journal of magnetism and magnetic materials》2012
The temperature and composition dependence of magnetic properties of Co–Cr co-substituted magnesium ferrite, Mg1−xCoxCrxFe2−xO4 (x=0.0–0.5), prepared by novel polyethylene glycol assisted microemulsion method, are studied. The synthesized materials are characterized by the Mössbauer spectrometer and standard magnetic measurements. Major hysteresis loops are measured up to the magnetic field of 50 kOe at 300, 200 and 100 K. The high field regimes of these loops are modeled using the Law of Approach to saturation to determine the first-order cubic anisotropy coefficient and saturation magnetization. Both the saturation magnetization and the anisotropy coefficient are observed to increase with the decrease in temperature for all Co–Cr co-substitution levels. Also, both the saturation magnetization and the anisotropy coefficient achieved maximum value at x=0.3 and x=0.2, respectively. Explanation of the observed behavior is proposed in terms of the site occupancy of the co-substituent, Co2+ and Cr3+ in the cubic spinel lattice. 相似文献
62.
Günseli Turgut Cin Seda Demirel Topel Abban Cakıcı Arzu Özek Yıldırım Ahmet Karadağ 《Journal of chemical crystallography》2012,42(4):372-380
Abstract
Two novel ferrocenyl substituted N-acetyl-2-pyrazolines, N-acetyl-3-(2-furyl)-5-ferrocenyl-2-pyrazoline (3) and N-acetyl-3-(2-thienyl)-5-ferrocenyl-2-pyrazoline (4), have been synthesized and characterized by FTIR, 1H-NMR, 13C-NMR techniques, elemental analysis and X-ray structure analysis. Thermal properties of these compounds have been determined by TGA, DTA and DSC analysis. Compound 3 (C19H18N2O2Fe) crystallizes in the monoclinic space group P21/c and Z = 4, with a = 8.6970(4) ?, b = 18.4725(9) ?, c = 11.0041(5) ?, β = 110.942(3)°. Compound 4 (C19H18N2OSFe) crystallizes in the orthorhombic space group Fdd2 and Z = 16, with a = 84.242(2) ?, b = 13.5416(5) ?, c = 5.9405(2) ?, β = 90°. In terms of crystal packing, each compound shows different molecular arrangement, which are stabilized by C–H···O intermolecular weak hydrogen bonds, and/or C–H···π interactions. 相似文献63.
Muhammad Nasir Ali Syed Muhammad Husnine Asit Saha Samir Kumar Bhowmik Sharanjeet Dhawan Turgut Ak 《Nonlinear dynamics》2018,94(3):1791-1801
In the present work, we observe the dynamical behavior of nonlinear and supernonlinear traveling waves for Sharma–Tasso–Olver (STO) equation. Exact solutions are derived using \({1}/{G^{^{\prime }}}\) expansion and modified Kudryashov methods. The wave transformation is used to transform STO equation into an ordinary differential equation. Combining Runge–Kutta fourth-order and Fourier spectral technique, we use a mixed scheme for the numerical study of STO equation. Since spectral methods expand the solution in trigonometric series resulting into higher-order technique and Runge–Kutta produces improved accuracy, we extract these qualities for a mixed scheme. Results so produced are presented graphically which provide a useful information about the dynamical behavior. Bifurcation behavior of nonlinear and supernonlinear traveling waves of STO equation is studied with the help of bifurcation theory of planar dynamical systems. It is observed that STO equation supports nonlinear solitary wave, periodic wave, shock wave, stable oscillatory wave and most important supernonlinear periodic wave. 相似文献
64.
Synthesis,antioxidant activity and SAR study of novel spiro-isatin-based Schiff bases 总被引:1,自引:0,他引:1
Sonmez Fatih Gunesli Zuhal Kurt Belma Zengin Gazioglu Isil Avci Davut Kucukislamoglu Mustafa 《Molecular diversity》2019,23(4):829-844
Molecular Diversity - A new series of 21 Schiff bases of spiro-isatin was synthesized, and their DPPH, CUPRAC and ABTS cation radical scavenging abilities were investigated for antioxidant... 相似文献
65.
In this Letter, Exp-function method is employed to obtain traveling wave solutions of the Fisher equation. It is shown that, on this example, the Exp-function method is easy to implement and concise method for nonlinear evolution equations in mathematical physics. 相似文献
66.
Gizem Gülsoy Toplan Turgut Takn Gkalp can Fatih Gger Mine Kürküolu Aye Civa Gülay Ecevit-Gen Afife Mat Kemal Hüsnü Can Baer 《Molecules (Basel, Switzerland)》2022,27(6)
The potential applications of Achillea species in various industries have encouraged the examination of their phytochemical components along with their biological potential. In the present study, phenolic contents and essential oil compositions together with the in vitro biological activities of the aerial parts from Achillea biebersteinii Afan. and Achillea millefolium subsp. millefolium Afan. collected from Turkey were evaluated. Different solvent extracts (n-hexane, chloroform, methanol, water) were prepared and their antimicrobial, anticholinesterase, and antioxidant activities were studied. The LC-MS/MS results revealed the presence of 16 different phenolic compounds, including chlorogenic acid, rutin, quercetin, and luteolin glycosides, in methanolic extracts. According to GC-FID and GC/MS results, the primary components of the oils were identified as 1,8-cineole (32.5%), piperitone (14.4%), and camphor (13.7%) in A. biebersteinii and 1,8-cineole (12.3%) and β-eudesmol (8.9%) in A. millefolium subsp. millefolium. The infusion and methanolic extracts of both species were found to be rich in their total phenolic content as well as their antioxidant and anticholinesterase activity. In contrast, the n-hexane and chloroform extracts of both species showed strong antimicrobial activity with MIC values ranging from 15 to 2000 μg/mL. Our findings suggest that the investigated Achillea species could be evaluated as potent natural agents, and further studies into the promising extracts are needed. 相似文献
67.
Turgut Önder 《manuscripta mathematica》1995,86(1):393-407
LetG be a finite group and letM be a unitary representation space ofG. We consider the existence problem of equivariant frame fields on the unit sphereS(M) whose orthogonal complements in the tangent bundleT(S(M)) admitG-equivariant complex structures. Under mild fixed point conditions we give a complete solution for this problem whenG is either ℤ/2ℤ or a finite group of odd order.
This article was processed by the author using theLaTEX style filecljourl from Springer-Verlag. 相似文献
68.
69.
Merve Yuzbasioglu Baran Zuhal Guvenalp Iclal Saracoglu Cavit Kazaz Bekir Salih L. Omur Demirezer 《Natural product research》2020,34(12):1669-1677
AbstractIn this study, phytochemical composition of Arnebia densiflora (AD) was determined and cytotoxic effects of the n-hexane extract and compounds isolated from this species on various cell lines were investigated. By means of serial chromatographic studies, 6 naphthoquinone derivatives were yielded, which are isovalerylalkannin, α-methyl-n-butyl alkannin, acetylalkannin, β-acetoxy isovalerylalkannin, alkannin and a new compound: 4-hydroxy 4-methyl valeryl alkannin. Structures of the isolated compounds were elucidated using UV, IR, 1D-2D NMR, MS and CD methods. Cytotoxic effects of the extract and isolated alkannins were investigated on L929, HeLa, HEp-2 cells. AD and the isolated compounds demonstrated moderate to strong cytotoxic effects (IC50 range: 4.92-172.35?µg/ml). The results of DNA fragmentation and caspase-3 activity studies on HeLa cells exhibited that AD and the naphthoquinones isolated from it caused cytotoxicity through induction of apoptosis. 相似文献
70.
W incorporated tin oxide (TO) thin films were grown via spray pyrolysis with various tungsten contents. The films were observed to be polycrystalline tetragonal crystal nature with (301) and (211) preferential planes. From EDX analysis, it was seen the tungsten concentrations in the TO films were slightly higher than ones in the starting solutions. Polyhedron-like and small rod like grains were observed in the SEM images. 3 at % W doped tin oxide film has minimum sheet resistance (44.67 Ohm) and resistivity (3.685 × 10?3 Ohm cm) values and maximum figure of merit (75.74 × 10?5 Ohm?1) value. The optical band gap (Eg) of pure film raised from 3.84 to 3.91 eV with 3 at % W contribution level. 相似文献