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Article Citation - WoS: 5Citation - Scopus: 6Synthesis, X-Ray Data, and Hall Effect Measurements of Li-Doped Tl-Ba Superconductor(Wiley-v C H verlag Gmbh, 2003) Kayed, TSLithium-doped Tl-based superconductor was prepared by adding an amount of 0.3 mol.% to the Tl1.8Ba2Ca2.2Cu3Ox compound. The usual solid-state reaction method has been applied under optimum conditions. The x-ray data of the sample show a tetragonal structure with a high ratio of Tl-2223 superconducting phase. The sample showed a transition at 125 K and the zero resistance was observed at 117 K. Longitudinal (transport) and transverse (Hall) resistivities were measured at different temperatures under different magnetic fields and the data were interpreted. A positive Hall coefficient was observed at normal state and a sign reversal appears at temperatures lower than the critical temperature. (C) 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.Article Citation - WoS: 6Citation - Scopus: 6Dielectric Dispersion at the Mn/Znpc Interfaces(Wiley-v C H verlag Gmbh, 2020) Qasrawi, Atef F.; Zyoud, Hadeel M.Herein, the effects of manganese transparent (150 nm) substrates on the structural, nonlinear optical, and dielectric properties of zinc phthalocyanine are explored. ZnPc thin films are observed to exhibit deformed crystal structure associated with remarkable enhancement in the light absorbability by 21 times at 2.62 eV and by 173 times in the near-infrared (NIR) region of light upon replacement of glass by transparent Mn substrates. The Mn layer also causes a redshift in the energy bandgap, allows generation of free carrier absorption process and increases the dielectric constant by more than 169% in the NIR region. The interaction between the manganese substrates with the organic ZnPc thin layers decreases the free holes density, widens the plasmon frequency range, and improves the drift mobility of holes. The nonlinear dielectric response with the highly improved light absorbability in the NIR range of light nominates the Mn/ZnPc thin films for optoelectronic applications.Article Citation - WoS: 11Citation - Scopus: 11Microstructural, thermal, and electrical properties of Bi1.7V0.3Sr2Ca2Ca3Ox glass-ceramic superconductor(Wiley-v C H verlag Gmbh, 2004) Kayed, TS; Calinli, N; Aksu, E; Koralay, H; Günen, A; Ercan, I; Cavdar, SA glass-ceramic Bi1.7V0.3Sr2Ca2Cu3Ox superconductor was prepared by the melt-quenching method. The compound was characterized by scanning electron microscopy, x-ray diffraction, differential thermal analysis, current-voltage characteristics, transport resistance measurements, and Hall effect measurements. Two main phases (BSCCO 2212 and 2223) were observed in the x-ray data and the values of the lattice parameters quite agree with the known values for 2212 and 2223 phases. The glass transition temperature was found to be 426 degreesC while the activation energy for crystallization of glass has been found to be E-a = 370.5 kJ / mol. This result indicates that the substitution of vanadium increased the activation energy for the BSCCO system. An offset T-c of 80 K was measured and the onset T-c was 100 K. The Hall resistivity rho(H) was found to be almost field-independent at the normal state. A negative Hall coefficient was observed and no sign reversal of rho(H) or RH could be noticed. The mobility and carrier density at different temperatures in the range 140-300 K under different applied magnetic fields up to 1.4 T were also measured and the results are discussed.Article Citation - WoS: 6Citation - Scopus: 6Design and characterization of (Al, C)/p-Ge/p-BN/C isotype resonant electronic devices(Wiley-v C H verlag Gmbh, 2015) Al Garni, S. E.; Qasrawi, A. F.In this work, a Ge/BN isotype electronic device that works as a selective microwave bandstop filter is designed and characterized. The interface is designed using a 50-m thick p-type BN on a 0.2-m thick p-type germanium thin film. The modeling of current-voltage characteristics of the Al/Ge/BN/C channel of the device revealed that the current is dominated by thermionic emission and by the tunneling of charged particles through energy barriers. The evaluation of the conduction parameters reflected a resonant circuit with a peak-to-valley current ratio of (PVCR) of 63 at a peak (V-p) and valley (V-v) voltages of 1.84 and 2.30V, respectively. The ac signal analysis of the Al/Ge/BN/C channel that was carried out in the frequency range of 1.0-3.0GHz displayed a bandstop filter properties with notch frequency (f(n)) of 2.04GHz and quality factor (Q) of 102. The replacement of the Al electrode by C through the C/Ge/BN/C channel caused the disappearance of the PVCR and shifted f(n) and Q to 2.70GHz and 100, respectively. The features of the Ge/BN device are promising as they indicate the applicability of these sensors in communication technology.Article Citation - WoS: 9Citation - Scopus: 9Electrical Properties of Bi1.5znsb1.5< Pyrochlore Ceramics(Wiley-v C H verlag Gmbh, 2003) Kayed, TS; Mergen, ABi1.5ZnSb1.5O7 pyrochlore samples were prepared by solid state reaction method. They were examined by x-ray diffraction and scanning electron microscopy. Single phase, belongs to the cubic pyrochlore structure, with a lattice parameter of 10.442 Angstrom and grain size that varies from 16 to 20 mum was obtained. The electrical properties were measured at different temperatures in the range 15-330 K under different applied magnetic fields up 1.4 T. In our measurements for Hall coefficient, Hall resistivity, and mobility; we noticed an anomalous behavior at two temperatures (around 250 and 310 K) which was supported by the I-V measurements (double transition of the slope of I-V characteristics (beta) at the same temperatures). This was discussed in terms of polarization phenomenon and mixed ionic-electronic conduction. (C) 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.Article Citation - WoS: 28Citation - Scopus: 27Photoelectronic and Electrical Properties of Cuin5s8< Single Crystals(Wiley-v C H verlag Gmbh, 2003) Qasrawi, AF; Gasanly, NMTo identify the impurity levels in CuIn5S8 single crystals, the dark electrical conductivity and photoconductivity measurements were carried out in the temperature range of 50-460 K. The data reflect the intrinsic and extrinsic nature of the crystals above and below 300 K, respectively. Energy band gaps of 1.35 and 1.31 eV at 0 K and 300 K, were defined from the dark conductivity measurements and the photocurrent spectra, respectively. The dark and photoconductivity data in the extrinsic temperature region reflect the existence of two independent donor energy levels located at 130 and 16 meV. The photocurrent-illumination intensity dependence (F) follows the law I(ph)alphaF(gamma), with gamma being 1.0, 0.5 and 1.0 at low, moderate and high intensities indicating the domination of monomolecular, bimolecular and strong recombination at the surface, respectively. In the intrinsic region and in the temperature region where the shallow donor energy level 16 meV is dominant, the free electron life time, tau(n), is found to be constant with increasing F. In the temperature region 140 K < T < 210 K, the free electron life time increases with increasing illumination intensity showing the supralinear character. Below 140 K, tau(n) decrease with decreasing illumination intensity. (C) 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.Article Citation - WoS: 16Citation - Scopus: 16Keggin Type-Polyoxometalate Decorated Ruthenium Nanoparticles: Highly Active and Selective Nanocatalyst for the Oxidation of Veratryl Alcohol as a Lignin Model Compound(Wiley-v C H verlag Gmbh, 2017) Baguc, Ismail Burak; Saglam, Serif; Ertas, Ilknur Efecan; Keles, Muhammed Nuri; Celebi, Metin; Kaya, Murat; Zahmakiran, MehmetDescribed herein is a new nanocatalyst system that efficiently works in the aerobic oxidation of veratryl alcohol (VA), which is formed by cleavage of beta-O-4 linkages in lignin, to veratraldehyde (VAL) under mild reaction conditions. The new nanocatalyst system comprised of ruthenium(0) nanoparticles supported on the Keggin type polyoxometalate (POM; K-3[PMo12O40]) network (Ru/POM) can simply and reproducibly be prepared by the dimethylamine-borane ((CH3)(2)NHBH3) reduction of ruthenium(III) chloride trihydrate (RuCl3.3H(2)O) in isopropanol solution of K-3[P Mo12O40] at room temperature. The characterization of Ru/POM by the combination of various analytical techniques reveals that the formation of well-dispersed ruthenium(0) nanoparticles with a mean diameter of 4.7 +/- 1.2nm on the surface of POM network structure. This new Ru/POM nanocatalyst displays remarkable activity (TOF=7.5mol VAld/mol Ru x h) at high selectivity (> 98%) and almost complete conversion (98%) in the aerobic oxidation of VA to VAld under mild conditions.Article Citation - WoS: 1Citation - Scopus: 1Characterization of Pbmo0.3w0.7< Crystal: a Potential Material for Photocatalysis and Optoelectronic Applications(Wiley-v C H verlag Gmbh, 2024) Isik, Mehmet; Gasanly, Nizami MamedPbMo0.3W0.7O4 semiconductor crystal, which contains the balanced ratios of Mo and W, is grown for the first time by Czochralski method. The structural and optical properties of the crystal are investigated in detail in the present study. Structural analysis shows that crystal has tetragonal structure like PbMoO4 and PbWO4 compounds. The optical characteristics are studied by transmission, Raman, FTIR and photoluminescence methods. The bandgap energy is found to be 3.18 eV, and the positions of the conduction and valence bands are determined. The vibrational characteristics are studied by means of Raman and FTIR spectroscopy techniques. Photoluminescence spectrum presents three peaks around 486, 529, and 544 nm which fall into the green emission spectral range. Taking into account the properties of the compound, it is stated that PbMo0.3W0.7O4 (or Pb(MoO4)(0.3)(WO4)(0.7)) has the potential to be used in water splitting applications and optoelectronic devices that emit green light.Article Citation - WoS: 7Citation - Scopus: 7Structural and Dielectric Properties of Ba1-x< Solid Solutions(Wiley-v C H verlag Gmbh, 2021) Qasrawi, A. F.; Sahin, Ethem Ilhan; Abed, Tamara Y.; Emek, MehribanHerein, lanthanum doping effects on the structural, dielectric, and electrical properties of Ba1-xLax(Zn1/3Nb2/3)O-3 (BZN) solid solutions are focused upon. The La contents which are varied in the range of 0.02-0.20 exhibit a solubility limit of x = 0.02. Although minor phases of Ba5Nb4O15 and Ba3LaNb3O12 appear for samples doped with La contents of x = 0.05 and x = 0.10, they play no remarkable role for the enhanced structural and dielectric properties of BZN. The La doping content of x = 0.02 succeeds in increasing the crystallite size by 51.16% and lowering the microstrain by 34.18% and defect concentration by 63.10%. La-doped BZN ceramics display higher values of relative density and electrical conductivity. The analyses of the dielectric spectra as a function of temperature display dielectric relaxation behavior above 120 degrees C. In the temperature range of 20-120 degrees C, La doping changes the temperature coefficient of dielectric constants from +30 ppm degrees C-1 in pure samples to -341 ppm degrees C-1 in samples doped with La contents of x = 0.10. The enhancements in structural parameters, density values, and dielectric responses that are achieved via La doping make BZN ceramics more suitable for electronic device fabrication.Article Citation - WoS: 32Citation - Scopus: 32Urine Analysis Using Ftir Spectroscopy: a Study on Healthy Adults and Children(Wiley-v C H verlag Gmbh, 2021) Sarigul, Neslihan; Kurultak, Ilhan; Gokceoglu, Arife Uslu; Korkmaz, FilizUrine spectra from 108 healthy volunteers are studied by attenuated total refraction-Fourier transform infrared (ATR-FTIR) spectroscopy. The spectral features are correlated with observable urine components. The variation of spectra within a healthy population is quantified and a library of reference spectra is constructed. Using the band assignments, these spectra are compared with both age-wise and gender-wise. Children show the least intensity variations compared to both adult groups. Young adults show the highest variation, particularly in the 1650 to 1400 cm(-1) and 1200 to 900 cm(-1) regions. These results indicate the importance of the size of the control group in comparative studies utilizing FTIR. Age-wise comparisons reveal that phosphate and sulfate excretion decreases with age, and that the variance of phosphate among individuals is higher with adults. As for gender-wise comparisons, females show a slightly higher citrate content at 1390 cm(-1) regardless of the age and they show a higher variance in the 1200 to 1000 cm(-1) region when compared to men.
