Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 5Citation - Scopus: 5Madelung Representation of Damped Parametric Quantum Oscillator and Exactly Solvable Schrödinger-Burgers Equations(American Institute of Physics, 2010) Atılgan Büyükaşık, Şirin; Pashaev, OktayWe construct a Madelung fluid model with time variable parameters as a dissipative quantum fluid and linearize it in terms of Schrödinger equation with time-dependent parameters. It allows us to find exact solutions of the nonlinear Madelung system in terms of solutions of the Schrödinger equation and the corresponding classical linear ordinary differential equation with variable frequency and damping. For the complex velocity field, the Madelung system takes the form of a nonlinear complex Schrödinger-Burgers equation, for which we obtain exact solutions using complex Cole-Hopf transformation. In particular, we give exact results for nonlinear Madelung systems related with Caldirola-Kanai-type dissipative harmonic oscillator. Collapse of the wave function in dissipative models and possible implications for the quantum cosmology are discussed. © 2010 American Institute of Physics.Article Citation - WoS: 19Citation - Scopus: 19Systematic Tuning the Hydrodynamic Diameter of Uniformed Fluorescent Silica Nanoparticles(American Chemical Society, 2011) Durgun, Gülay; Ocakoğlu, Kasım; Özçelik, SerdarWe report a facile method for systematic tuning the hydrodynamic diameter of uniformed fluorescent silica particles in the size range from 12 to 465 nm. Dynamic light scattering and electron microscopy studies demonstrate that the hydrodynamic size distribution of the silica particles is uniform. We show that the initial amounts of ethanol and ammonia are essential to tune the size of these particles. The hydrodynamic diameter of such a particle increases as the amount of ammonia is increased. On the other hand, an increase in the amount of ethanol leads to the formation of smaller particles. Higher initial amount of ethanol yield an increase in the concentration of ethoxide ions and a decrease in the concentration of hydroxide ions. Such control over the concentration of hydroxide ion, which is responsible for the formation of siloxane bonds, causes a controlled-growth of the silica particles, resulting in precise tuning the hydrodynamic size. We confirm that a linear relationship exists between size and brightness of particles, demonstrating that the amount of dye molecules in such particles can be regulated by the presented method. We prove that the silica network provides protection for dye molecules encapsulated in particles against solvents, fluorescence quenchers, and unfavorable pH of environments. Moreover, the fluorescent silica particles with the size of 12, 50 and 250 nm were found to not be cytotoxic against the epithelial cell lines of MCF7 and PC3 even when the dosage levels up to 1.0 mg/ml and incubation periods up to 72 hours were applied.