Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
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Article Citation - Scopus: 2Deformation Behavior of Nanostructured Aluminum: Experiment and Computational Study(Elsevier Ltd, 2023-04) Deka, Surja; Mozafari, Farzin; Mallick, Ashis K.Nanocrystalline metals have been processed from powder predecessors in recent times in significant ways, and nowadays, materials are starting to be manufactured which are not only strong but also ductile. Nanocrystalline aluminum (Average grain size 51 nm) was synthesized through high-energy ball milling at the room temperature of microcrystalline powder. The particle size and crystallite sizes were obtained by Williamson Hall and found to be in good correlation with transmission spectroscopy (TEM) data. There was a significant increase in the mechanical properties of nanostructured aluminum in comparison to coarse-grained aluminum. Moreover, a phenomenological model of large-deformation, isotropic, rate-dependent plasticity is developed, which takes into account pressure dependency, plastic dilatation, and non-normal flow. The model has been incorporated into a finite element program. Compression and tension experiments were performed on nanocrystalline aluminum, and the constitutive parameters within the model were estimated from these experiments. The present study shows that the constitutive model successfully simulates the mechanical response of nanocrystalline aluminum with reasonable accuracy using our numerical finite-element capability. © 2023 Elsevier B.V., All rights reserved.Article Citation - WoS: 2Citation - Scopus: 2Cation Exchange Mediated Synthesis of Bright Au@ZnTe Core-Shell Nanocrystals(IOP Publishing Ltd, 2020-10-16) Sadeghi, Sadra; Melikov, Rustamzhon; Sahin, Mehmet; Nizamoglu, SedatThe synthesis of heterostructured core-shell nanocrystals has attracted significant attention due to their wide range of applications in energy, medicine and environment. To further extend the possible nanostructures, non-epitaxial growth is introduced to form heterostructures with large lattice mismatches, which cannot be achieved by classical epitaxial growth techniques. Here, we report the synthetic procedure of Au@ZnTe core-shell nanostructures by cation exchange reaction for the first time. For that, bimetallic Au@Ag heterostructures were synthesized by using PDDA as stabilizer and shape-controller. Then, by addition of Te and Zn precursors in a step-wise reaction, the zinc and silver cation exchange was performed and Au@ZnTe nanocrystals were obtained. Structural and optical characterization confirmed the formation of the Au@ZnTe nanocrystals. The optimization of the synthesis led to the bright nanocrystals with a photoluminescence quantum yield up to 27%. The non-toxic, versatile synthetic route, and bright emission of the synthesized Au@ZnTe nanocrystals offer significant potential for future bio-imaging and optoelectronic applications.Article Citation - WoS: 51Citation - Scopus: 53CdSe/ZnS Quantum Dot Films for High Performance Flexible Lighting and Display Applications(IOP Publishing Ltd, 2016-06-10) Altintas, Yemliha; Genc, Sinan; Talpur, Mohammad Younis; Mutlugun, EvrenColloidal quantum dots have attracted significant interest in recent years for lighting and display applications and have recently appeared in high-end market products. The integration of quantum dots with light emitting diodes has made them promising candidates for superior lighting applications with tunable optical characteristics. In this work we propose and demonstrate high quality colloidal quantum dots in their novel free-standing film forms to allow high quality white light generation to address flexible lighting and display applications. High quality quantum dots have been characterized using transmission electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, steady state and time resolved photoluminescence and dynamic light scattering methods. The engineering of colloidal quantum dot composition and its optical properties in stand-alone film form has led to the experimentally high NTSC color gamut of 122.5 (CIE-1931) for display applications, color rendering index of 88.6, luminous efficacy of optical radiation value of 290 lm/W-opt and color temperature of 2763 K for lighting applications.