Sürdürülebilir Kalkınma Amaçları
Yazarlar
Yayınlar
- Kitap BölümüYalnız künye2023Metasurfaces
Kaya, Yunus
The purpose of this book chapter is to ensure an extensive and appropriate definition of MSs, to determine their outstanding features, and also to emphasize some of the advantages that may be gained by using them. A superior property of MSs is their low loss behavior in contrast to MMs. Therefore, MSs permit us to use the extraordinary properties of MMs such as refraction and reflection without incurring production complications and the losses related to MMs.
- MakaleAçık Erişim2019Scopus SJRQ2Modification of eutectic Al-Si alloys by Sr and CuSn5
Çolak, Murat
Enhanced properties can be achieved in Al-Si alloys by several alloying element additions. Typical modifiers are Na, Sr, and Sb that alters Si into a fibrous structure. Fluidity and mechanical properties increase as well as machinability can be improved. In this work, eutectic Al-Si alloy was modified with Al10Sr, CuSn5, and Al10Sr + CuSn5 master alloys. Microstructural characterization was carried out by optical and scanning electron microscopy. Density and hardness of the samples were measured. Wear tests were carried out. It was found that Sr modified Al12Si revealed better performance than CuSn modified.
AtıfScopus21WoS19OpenAlex21
İncele - BildiriAçık Erişim2017Optimization of RT superplasticity of UFG Zn-22Al alloy by applying ECAP at different temperatures and phase regions
Demirtas, M.; Yanar, H.; Purcek, G.; Estrin, Y.; Liao, X.
Zn-22Al alloy was subjected to either one-step or two-step equal channel pressing (ECAP) to investigate the effect of processing temperature on its microstructure and room temperature (RT) superplasticity. In one-step ECAP processes, 4 passes ECAP were applied to the alloy at different temperatures: RT, 100°C and 250°C in two-phase region below eutectoid temperature and 350°C in single-phase region above eutectoid temperature. In two-step ECAP processes, one-step ECAP-processed samples were subjected to four more passes ECAP at RT. Considering the one-step ECAP processing, RT superplasticity increased with decreasing ECAP temperature as expected, and the highest RT superplasticity was achieved as 350% after 4 passes ECAP at RT. On the other hand, application of 4 more passes ECAP at RT to the sample showing the lowest superplastic elongation after one-step ECAP (the sample processed at 350°C) resulted in the maximum RT elongation of 400% at a high strain rate of 5×10-2 s-1. These results suggest that first step temperature of two-step ECAP process is needed to increase above the eutectoid point of Zn-22Al alloy to achieve high RT superplasticity. These results were attributed to the changes in microstructure inside the single-phase and two-phase regions during the processes.
AtıfScopus12WoS10OpenAlex9İncele - MakaleYalnız künye2016Scopus SJRQ2Morphological and optical comparison of the Si doped GaN thin film deposited onto the transparent substrates
Ozen, Soner; Senay, Volkan; Pat, Suat; Korkmaz, Sadan
The aim of this paper is to expand the body of knowledge about the silicon doped gallium nitride thin films deposited on different substrates. The physical properties of the Si doped GaN thin films deposited on the glass and polyethylene terephthalate substrates by thermionic vacuum arc which is plasma production technique were investigated. Thermionic vacuum arc method is a method of producing pure material plasma. The Si doped GaN thin films were analyzed using the following methods and the devices: atomic force microscopy, X-ray diffraction device, spectroscopic ellipsometer and energy dispersive X-ray spectroscopy detector. The produced Si doped GaN thin films are in the (113) orientation. The thicknesses and refractive index were determined by using Cauchy dispersion model. Surface morphologies of produced thin films are homogenous and low roughness. Our analysis showed that the thermionic vacuum arc method present important advantages for optical and industrial applications.
AtıfScopus8WoS7OpenAlex10İncele - BildiriAçık Erişim2016The effects of fuel type in synthesis of NiFe2O4 nanoparticles by microwave assisted combustion method
Karakaş, Zeynep Karcioǧlu; Boncukçuoǧlu, Recep; Karakaş, Ibrahim H.; Durak, R.; Tuzemen, S.
In this study, it was investigated the effects of the used fuels on structural, morphological and magnetic properties of nanoparticles in nanoparticle synthesis with microwave assisted combustion method with an important method in quick, simple and low cost at synthesis of the nanoparticles. In this aim, glycine, urea and citric acid were used as fuel, respectively. The synthesised nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmet-Teller surface area (BET), and vibrating sample magnetometry (VSM) techniques. We observed that fuel type is quite effective on magnetic properties and surface properties of the nanoparticles. X-ray difractograms of the obtained nanoparticles were compared with standard powder diffraction cards of NiFe2O4 (JCPDS Card Number 54-0964). The results demonstrated that difractograms are fully compatible with standard reflection peaks. According to the results of the XRD analysis, the highest crystallinity was observed at nanoparticles synthesized with glycine. The results demonstrated that the nanoparticles prepared with urea has the highest surface area. The micrographs of SEM showed that all of the nanoparticles have nano-crystalline behaviour and particles indication cubic shape. VSM analysis demonstrated that the type of fuel used for synthesis is highly effective a parameter on magnetic properties of nanoparticles.
AtıfScopus22WoS15OpenAlex18İncele - MakaleYalnız künye2016Scopus SJRQ1Optical, morphological properties and surface energy of the transparent Li4Ti5O12 (LTO) thin film as anode material for secondary type batteries
Özen, Soner; Şenay, Volkan; Pat, Suat; Korkmaz, Şadan
LTO thin film was deposited for the first time on a glass microscope slide (MS) by RF magnetron sputtering technology. This method has been suitable for preparation of high-quality thin films. The surface properties of the produced film were determined by atomic force microscope (AFM). The surface of the produced film appeared smooth and homogeneous. LTO coated on MS had compact structure and low roughness. A UV-vis spectrophotometer was used to determine intensity of light passing through the samples. Thus, according to the results obtained the produced film was highly transparent. The refractive index of the LTO thin film was presented in a low MSE value by spectroscopic ellipsometry (SE) and it was about 1.5. The optical band gap (Eg) was determined by the Tauc method. The produced LTO thin film exhibited a wide band gap semiconductor property with a band gap energy of about 2.95 eV. Finally, the surface free energy of the LTO thin film was calculated from the contact angle measurements using the Lewis acid-base, OWRK/Fowkes, Wu and Zisman methods.
AtıfScopus24WoS23OpenAlex27İncele - DergiIOP Conference Series: Materials Science and Engineering
- DergiMaterials Research Express
- DergiJournal of Physics: Conference Series
- DergiJournal of Physics D: Applied Physics