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The Effect of Condensation on the Morphology and Magnetic Properties of Modified Barium Hexaferrite(BaFe_(12)O_(19)) 被引量:1
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作者 Z.Durmus H.Sozeri +1 位作者 M.S.Toprak A.Baykal 《Nano-Micro Letters》 SCIE EI CAS 2011年第2期108-114,共7页
We present a comparison for the effect of condensation on the morphology and magnetic prop erties of oleic acid modified BaFe_(12)O_(19) nanoparticles.Two different samples of BaFe_(12)O_(19) nanoparticles were synthe... We present a comparison for the effect of condensation on the morphology and magnetic prop erties of oleic acid modified BaFe_(12)O_(19) nanoparticles.Two different samples of BaFe_(12)O_(19) nanoparticles were synthesized by dehydration(Z1) and rotary evaporation(Z2) method,respectively.Oleic acid was used as the surface modification agent to observe the morphological and magnetic changes.The nanoparticles were analyzed by XRD,FTIR,TGA,SEM,and VSM techniques for structural and physicochemical characteris tics.Crystallographic analysis reveals the phase as hexaferrite and the average crystallite size of Z1 and Z2 is 21±3 nm and 17±2 nm,respectively.Rotary evaporator accelerates the condensation process in viscous gel(Z2).Due to the use of rotary evaporator,the coating with oleic acid for Z2 product has been accomplished very well,as compared with Z1.As a result,saturation magnetization of Z2 sample is much lower than that of Z1 sample. 展开更多
关键词 BAFE12O19 NANOPARTICLES Rotary evaporatory CONDENSATION Magnetic properties
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Hydrothermal Synthesis and Characterization of PEG-Mn_3O_4 Nanocomposite 被引量:1
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作者 E.Karaoglu H.Deligoz +2 位作者 H.Sozeri A.Baykal M.S.Toprak 《Nano-Micro Letters》 SCIE EI CAS 2011年第1期25-33,共9页
Here, we report on the synthesis of PEG-Mn_3O_4 nanocomposite(NP's) via a hydrothermal route by using Mn(acac)2, ethanol, NH3 and PEG-400. The crystalline phase was identified as Mn_3O_4. The crystallite size of t... Here, we report on the synthesis of PEG-Mn_3O_4 nanocomposite(NP's) via a hydrothermal route by using Mn(acac)2, ethanol, NH3 and PEG-400. The crystalline phase was identified as Mn_3O_4. The crystallite size of the PEG-Mn_3O_4 nanocomposite was calculated as 12±5 nm from X-ray line profile fitting and the average particle size from TEM was obtained as 200 nm. This reveals polycrystalline character of Mn_3O_4 NP's. The interaction between PEG-400 and the Mn_3O_4 NP's was investigated by FTIR. Temperature independent AC conductivity of PEG-Mn_3O_4 nanocomposite beyond 20 k Hz provides a strong evidence of ionic conduction through the structure. The conductivity and permittivity measurements strongly depend on the secondary thermal transition of nanocomposite beyond 100. Above that temperature, Mn_3O_4 particles may interact with each other yielding a percolated path that will facilitate the conduction. On the other hand, the relatively lower activation energy(Ea=0.172 e V) for relaxation process suggests that polymer segmental motions of PEG and electrons hopping between Mn2+and Mn3+may be coupled in the sample below 100. Room temperature magnetization curve of the sample does not reach to a saturation, which indicates the superparamagnetic character of the particles. As the temperature increases, the frequency at which(ε′′) reaches a maximum shifted towards higher frequencies. The maximum peak was observed at 1.4 k Hz for 20 while the maximum was detected at 23.2 k Hz for 90. 展开更多
关键词 SPINELS Magnetic nanomaterials CONDUCTIVITY Magnetic properties Hydrothermal Synthesis
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Effect of Hydrolyzing Agents on the Properties of Poly(Ethylene Glycol)-Fe_3O_4 Nanocomposite 被引量:1
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作者 E.Karaoglu H.Kavas +2 位作者 A.Baykal M.S.Toprak H.Szeri 《Nano-Micro Letters》 SCIE EI CAS 2011年第2期79-85,共7页
Poly(ethylene glycol)(PEG) assisted hydrothermal route has been used to study the influence of the hydrolyzing agent on the properties of PEG-iron oxide(Fe_3O_4) nanocomposites.Iron oxide nanoparticles(NPs),as confirm... Poly(ethylene glycol)(PEG) assisted hydrothermal route has been used to study the influence of the hydrolyzing agent on the properties of PEG-iron oxide(Fe_3O_4) nanocomposites.Iron oxide nanoparticles(NPs),as confirmed by X-ray diffraction analysis,have been synthesized by a hydrothermal method in which Na OH and NH_3 were used as hydrolyzing agents.Formation of PEG-Fe_3O_4 nanocomposite was confirmed by Fourier transform infrared spectroscopy(FTIR).Samples exhibit different crystallite sizes,which estimated based on line profile fitting as 10 nm for NH_3 and 8 nm for Na OH hydrolyzed samples.The average particle sizes obtained from transmission electron microscopy was respectively 174±3 nm for Na OH and 165±4 nm for NH3 gas hydrolyzed samples.Magnetic characterization results reveal superparamagnetic characteristics despite a large particle size,which indicate the absence of coupling between the nanocrystals due to the presence of polymer in the nanocomposites.The conductivity curve demonstrates that σDC is strongly temperature dependent. 展开更多
关键词 MAGNETITE PEG Hydrothermal synthesis CONDUCTIVITY MAGNETIZATION
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Temperature-Irradiance Matrix and Determination of Temperature Coefficients of a Monocrystalline PV Module
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作者 Bazkir Ozcan Meric Seval 《Open Journal of Energy Efficiency》 2022年第3期108-121,共14页
Photovoltaic (PV) modules performance testing and energy rating as described in IEC 61853-1 standard depend on electrical performance parameters (short-circuit current, open-circuit voltage, maximum-power) of PV modul... Photovoltaic (PV) modules performance testing and energy rating as described in IEC 61853-1 standard depend on electrical performance parameters (short-circuit current, open-circuit voltage, maximum-power) of PV modules as a function of temperature and irradiance. In this work, in order to precisely determine the effects of temperature on the electrical parameters of a monocrystalline PV module, the temperature controlled, xenon light based solar simulator system with irradiance attenuating masks was used. This solar simulator, according to the IEC 60904-9 standard in terms of spectral match, spatial non-uniformity and temporal instability has A+A+A+ classes which are two times better than the standard requirements for a solar simulator to be used in PV module measurements. Moreover, the thermal chamber used in this work is a closed type chamber with fast opening door for not allowing the distortion of temperature uniformity over the surface of PV modules under test. Within about 2 m × 2 m area within 15°C to 75°C temperature interval, the temperature uniformity obtained for this system is less than 1.0°C which is almost two times better than the IEC 60891 standard requirements (±2.0°C). The temperature and irradiance dependent measurements of the electrical performance parameters of a mono-crystalline PV module at various irradiance levels and the evaluation of its temperature coefficients [α (% °C<sup>-</sup><sup>1</sup>), β (% °C<sup>-</sup><sup>1</sup>) and δ (% °C<sup>-</sup><sup>1</sup>)] were done by implementing the interpolation method described in IEC 60891 standard. 展开更多
关键词 PHOTOVOLTAIC Temperature Coefficient LINEARITY Energy Rating
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Characterization of Simulator and Relative Spectral Responsivity Measurements of Photovoltaic Modules with Band Pass Filter Technique
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作者 Meric Seval Bazkir Ozcan 《Open Journal of Energy Efficiency》 2022年第3期71-87,共17页
One of the most important parameter used for the evaluation of the energy rating of PV modules is, their spectral responsivities which are the measure of electrical performance parameters per incident solar radiation.... One of the most important parameter used for the evaluation of the energy rating of PV modules is, their spectral responsivities which are the measure of electrical performance parameters per incident solar radiation. In this work, spectral responsivity measurements of a mono-crystalline, a poly-crystalline, a CIGS thin film and a bifacial module were measured using xenon-based flash type solar simulator system and a set of band pass filters. For the comprehensive characterization of parameters that may influence the spectral responsivity measurements, initially the simulator system was characterized both optically and thermally according to the IEC60904-9 and IEC60891 standard requirements. The optical characterizations in terms of spectral match, spatial non-uniformity and temporal instability indicate that the measured results (~3.0%, ~0.30% and ~0.20%) according to the IEC 60904-9 standard’s classification requirements correspond to A+A+A+ classes. Moreover, thermal characterizations in terms of the temperature uniformity show that over the 2 × 2 m area temperature uniformity of simulator system’s light distribution (1&ordm;C) is almost two times better than the IEC 60891 standard requirements (±2&ordm;C). Next, PV modules were electrically stabilized according to the IEC 61215-2 standard requirement’s (stability test) to reduce the fluctuations in their electrical performance parameters. Then, using the band pass filters, temperature controlled xenon-based solar simulator system and a reference PV module of the spectral responsivity of PV modules were measured from 400 nm to 1100 nm with 50 nm steps with relative uncertainty of 10<sup>-3</sup> level. 展开更多
关键词 Photovoltaic Modules RESPONSIVITY Solar Simulator Band Pass Filters
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MnFe2O4@PANI@Ag Heterogeneous Nanocatalyst for Degradation of Industrial Aqueous Organic Pollutants 被引量:1
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作者 Md.Amir U.Kurtan +1 位作者 A.Baykal H.Sozeri 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2016年第2期134-141,共8页
This paper reports a stable heterogeneous nanoparticles catalyst MnFe2O4@PANI@Ag for the degradation of azo dyes. In this synthesizing method, MnFe204 is used as magnetic core and polyaniline (PANI) a linker to stab... This paper reports a stable heterogeneous nanoparticles catalyst MnFe2O4@PANI@Ag for the degradation of azo dyes. In this synthesizing method, MnFe204 is used as magnetic core and polyaniline (PANI) a linker to stabilize the Ag nanoparticles (NPs) on the surface of catalyst. The method has a high ability to prevent Ag NPs from aggregation on the PANI surface, thus resulting in small size and highly dispersed Ag NPs. The composition and nano-structural features of polycrystalline sample were studied by X-ray powder diffractometry, Fourier transform infrared spectroscopy, and scanning electron microsco- py. Vibrating sample magnetometer measurements proved the super-paramagnetic property of the catalyst, and UV results demonstrated that MnFe2O4@PANI@Ag has a high ability to reduce the azo dyes, which come from industrial wastes in the form of pollutant. The nanocomposites could be readily separated by magnet and reused for the next four reductions with high generation efficiency. 展开更多
关键词 Ag NPs MnFe2O4 Magnetic nanocatalyst Catalytic degradation Azo dyes
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