Yazar "Cengiz, Erhan" seçeneğine göre listele
Listeleniyor 1 - 6 / 6
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe A comprehensive research on gamma-ray attenuation characteristics of the metal-doped hap and natural animal bone(Gümüşhane Üniversitesi, 2020) Köksal, Oğuz Kağan; Cengiz, Erhan; Tozar, Ali; Karahan, İsmail Hakkı; Apaydın, GökhanThis investigation focuses on the gamma ray attenuation parameters of natural animal bone, iron, cobalt, copper and zinc doped Nano hydroxyapatite artificial bone powders and pure hydroxyapatite. The present specimens were excited by means of gamma ray photons with 59.5 keV energy radiated from a 241-Amercium annular radioactive source with 50 mCi activity by means of narrow beam transmission geometry. The transmitted gamma-rays were counted with using Ultra Low Energy Germanium (Ultra-LEGe) detector with a resolution 150 eV at 5.95 keV. The gamma-ray attenuation characteristics such as mass attenuation coefficient (MAC) (µ/ρ), linear attenuation coefficient (LAC) (µ), half value layer (HVL), tenth value layer (TVL) and mean free path (MFP), which has a significant role in the attenuation studies, are also calculated. The values obtained were checked with the predicted values from the XCOM NIST. The results show that the attenuation data of the metal-doped hydroxyapatite synthetic bone dust is very close to the value of the natural animal bone.Öğe Determination of valence electronic structure of Ni in Ni-B alloy coatings using K?-to-K? X-ray intensity ratios(Pergamon-Elsevier Science Ltd, 2019) Cengiz, Erhan; Koksal, Oguz Kagan; Apaydin, Gokhan; Karahan, Ismail Hakki; Unal, ErsinIn this study, K-beta-to-K-alpha X-ray intensity ratios of Ni in Ni-B alloy coatings were investigated. These samples were excited by 59.5 keV gamma-rays from a Am-241 annular radioactive source. K X-rays emitted by the samples were counted using an Ultra-LEGe detector with a resolution of 150 eV at 5.9 keV. The K-beta-to-K-alpha X-ray intensity ratios of Ni-B alloys are compared with pure Ni and each other. Deviations between the results were explained by the change in valence electronic structures of Ni in Ni-B alloy coatings.Öğe Electronic Structure Study of Ni-B Alloy Coatings by XAFS Technique(Springer, 2021) Ozkendir, O. Murat; Cengiz, Erhan; Karahan, I. Hakki; Klysubun, WantanaThe crystal and electronic structure properties of Ni-B (nickel-boron) alloy coatings produced by an electrodeposition method have been investigated. The crystal structures of the alloy coatings were determined by x-ray diffraction patterns and supported by extended x-ray absorption fine structure (EXAFS) spectroscopy. The local atomic structure around the Ni atom was obtained from EXAFS studies at the Ni K-edge, and the EXAFS data were fitted with theoretical calculations. With the addition of boron atoms in the nickel environment, NiB composite alloys were formed in the crystals with an orthorhombic Cmcm structure. The analysis revealed a limited effect of boron doping in the electronic structure of the nickel atoms. Boron atoms were determined as sitting between the Ni atoms and causing a disturbance in the crystal structure due to providing inhomogeneous interstitial potential and defects.Öğe Electronic structure study of the bimetallic Cu1-xZnx alloy thin films(Taylor & Francis Ltd, 2018) Ozkendir, O. Murat; Cengiz, Erhan; Mirzaei, Mahmoud; Karahan, I. Hakki; Ozdemir, Rasim; Klysubun, WantanaA series of Zn doped copper materials were investigated upon their crystal and electronic structure with the general formula Cu1-xZnx. CuZn alloys were produced via electrodeposition method. Galvanostatic deposition was preferred for the deposition. Crystal properties of the samples were studied via X-ray diffraction (XRD) patterns and supported by the X-ray absorption fine structure spectroscopy (XAFS) data. According to the crystal structure analysis, crystal geometries of the substituted samples were mainly determined in bcc cubic. The study has revealed that, low amount of Zn substitution (0.1M) are inactive in the molecular interplays and treated as an impurity in fcc copper environment. However, higher Zn concentrations (> 0.1 M) have built bcc structure under the influence of the highly overlapped 4p levels wavefunctions of the neighbouring Cu and Zn atoms. Thus, 0.1 M zinc substitution has been determined as a threshold of the phase transition from fcc to the bcc structure.Öğe K?-to-K? X-ray intensity ratio studies on changes of valance electron structures of nickel in Ni-B/hBN composite coatings(Pergamon-Elsevier Science Ltd, 2022) Cengiz, Erhan; Karahan, Ismail HakkiIn this study, K beta/K alpha X-ray intensity ratio values of nickel in Ni coating and Ni-B/hBN (hBN: hexagonal Boron Nitride) composite coatings have been determined by the Energy Dispersive X-ray fluorescence spectroscopy (EDXRF) method. The K beta/K alpha X-ray intensity ratios of nickel in the Ni coating and Ni-B/hBN composite coatings have been compared with theoretical, experimental, and fitted data of the pure nickel. X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) measurements have been performed to observe how hBN particles with different bath concentrations affected the crystal structure and microstructure, respectively. The valence electronic structure of Ni in the coatings has been determined by comparing the experimental K beta/K alpha X-ray intensity ratios with Multiconfiguration Dirac-Fock (MCDF) predictions for various electron structures of Ni. The results show that while the values of the K beta/K alpha X-ray intensity ratio of the Ni-B/hBN composite coatings over pure Ni coatings increases, the 3d electron populations decreases. The change in the valence electronic structure were interpreted through charge transfer and rearrangement processes.Öğe A research on the gamma ray attenuation characteristics for real bone and manganese substituted artificial bone dust(2020) Koksal, Oguz Kagan; Tozar, Ali; Cengiz, Erhan; Karahan, Ismail Hakki; Apaydın, GökhanThis research focalized on the gamma ray attenuation charesteristics of real bone andHistory:manganese substituted Nano hydroxyapatite artificial bone dusts. The current samples wereReceived:24.03.2019excited with using 59.5 keV photons emitted from an 241Am annular radioisotope source withAccepted:29.01.202050 mCi activity by using a narrow beam transmission geometry and detected with using UltraKeywords:Low Energy Germanium detector with a resolution 150 eV at 5,95 keV experimentally. TheAttenuationgamma-ray attenuation parameters such as linear attenuation coefficient, half value layer, tenthcharesteristics, Mnvalue layer and mean free path are also calculated experimentally and theoretically. Thesubstituted artificialpresent results points out that the attenuation values of the manganese substitutedbone dust, Real bone,hydroxyapatite artificial bone dust is very close to the value of the real bone.Transmission
