Scopus İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8651

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  • Article
    Citation - WoS: 1
    Citation - Scopus: 2
    On the Complementary Nabla Pachpatte Type Dynamic Inequalities Via Convexity
    (Elsevier, 2024) Kaymakcalan, Billur; Kayar, Zeynep
    Pachpatte type inequalities are convex generalizations of the well-known Hardy-Copson type inequalities. As Hardy-Copson type inequalities and convexity have numerous applications in pure and applied mathematics, combining these concepts will lead to more significant applications that can be used to develop certain branches of mathematics such as fuctional analysis, operator theory, optimization and ordinary/partial differential equations. We extend classical nabla Pachpatte type dynamic inequalities by changing the interval of the exponent delta from delta > 1 to delta < 0. Our results not only complement the classical nabla Pachpatte type inequalities but also generalize complementary nabla Hardy-Copson type inequalities. As the case of delta < 0 has not been previously examined, these complementary inequalities represent a novelty in the nabla time scale calculus, specialized cases in continuous and discrete scenarios, and in the dual outcomes derived in the delta time scale calculus.
  • Article
    Citation - WoS: 15
    Citation - Scopus: 16
    Binary Phase Shift Keying-Subcarrier Intensity Modulation Performance in Weak Oceanic Turbulence
    (Elsevier, 2019) Baykal, Yahya; Ata, Yalcin; Gokce, Muhsin Caner
    The performance analysis of underwater wireless optical communication (UWOC) system that employs binary phase shift keying-subcarrier intensity modulation (BPSK-SIM) is investigated in weak oceanic turbulence. BPSK-SIM Gaussian beam and finite sized positive-intrinsic-negative (PIN) photodetector are employed at the transmitter and at the receiver, respectively. Bit error rate (BER) is taken as the performance indicator and in the evaluation of the BER, the required signal power and the aperture averaged scintillation index are obtained respectively by the use of the extended Huygens-Fresnel principle and the Rytov theory. Considering various noise types in underwater turbulence, BER variations are examined versus the oceanic turbulence parameters and the photodetector parameters, namely receiver aperture diameter, PIN-responsivity, noise factor, load resistor, and the electronic bandwidth. (c) 2019 Elsevier B.V. All rights reserved.
  • Article
    Citation - WoS: 10
    Citation - Scopus: 9
    Hydrogen Recombination on a Mixed Adsorption Layer at Saturation on a Metal Surface: H→(D+h)sat+ni
    (Elsevier, 2003) Güvenç, ZB; Güvenç, D
    Interactions of H atom beams with (D + H)-covered Ni(1 0 0) surfaces are simulated at saturation level of 0.93 monolayer using quasi-classical microcanonical trajectory method. The Ni substrate is treated as a non-rigid multilayer slab using an embedded-atom method. The model many-body potential energy surface London-Eyring-Polanyi-Sato used to characterize the interactions between H-H and H-Ni(1 0 0) systems parameterized by fitting to the results of detailed total-energy calculations based on density functional theory. Since most of the incident H atoms trap to form hot atoms, reactions between the projectile atom and adsorbates are mainly due to the hot atom process. Results of a linear behavior of the total HD and quadratic behavior of the D-2 yields with the initial D coverage, in addition, significantly low secondary reactions between the adsorbates are found to be in good agreement with the experiment. In addition distributions of the rotational states of the product molecules, molecular desorption angles, vibrational states of the product molecules, molecular formation and desorption time, total and translational energies of the product molecules are also calculated as functions of different H and D coverages on the surface. (C) 2003 Elsevier Science B.V. All rights reserved.
  • Article
    Citation - WoS: 73
    Citation - Scopus: 70
    Energetics and Structures of Small Clusters: Ptn, N=2-21
    (Elsevier, 2003) Sebetci, A; Güvenç, ZB
    The Voter and Chen version of an embedded-atom model, derived by fitting to experimental data of both diatomic molecule and bulk platinum simultaneously, has been applied to study the locally stable structures, energies and growth patterns of small platinum clusters in the size range of N = 2-21. Using molecular dynamics and thermal quenching simulations, the global minima and the other locally stable structures have been distinguished from those stationary structures that correspond to saddle points of the potential energy surface. Ten thousand independent initial configurations generated at high temperatures (about 2600 K) were used to obtain the number of isomers and the probabilities of sampling different basins of attractions, for each size of the clusters. Their energy spectra have been analyzed. Comparisons have been made with the results of previous calculations using electronic structure and empirical potential methods. Although many of the lowest energy structures correspond to icosahedral growth, a number of new structures have been identified for N = 15, 16, 17, 18, 20 and 21. It has been found that the lowest energy structures are not always the most probable isomers for each size. (C) 2002 Elsevier Science B.V. All rights reserved.
  • Article
    Citation - WoS: 12
    Citation - Scopus: 16
    Fast Fluorometric Enumeration of E. Coli Using Passive Chip
    (Elsevier, 2019) Cogun, Ferah; Yildirim, Ender; Boyaci, Ismail Haklu; Cetin, Demet; Ertas, Nusret; Kasap, Esin Nagihan; Dogan, Uzeyir
    In this report, a passive microfluidic chip design was developed for fast and sensitive fluorometric determination of Escherichia coli (E. coli) based on sandwich immunoassay. Initially, magnetic nanoparticles (MNPs) and chitosan modified mercaptopropionic acid capped cadmium telluride (CdTe) quantum dots (QDs) were functionalized with E.coli specific antibody to form a sandwich immunoassay with the E. coli. The magnetic separation and preconcentration of the E.coli from the sample solution was performed in the vial. Conjugation of QDs to the magnetically captured E. coli and washing were performed using a passive type of microchip. The microfluidic chip consists of four microchambers connected to each other by microchannels which act as capillary valves. Signal measurement was performed at the last chamber by using a hand-held spectrofluorometer equipped with a fiber optic reflection probe. The selectivity of the method was tested with Enterobacter aerogenes (E. aerogenes) and Salmonella enteritidis (S. enteritidis), it was observed that these bacteria have no interference effect on E.coli determination. The calibration curve was found to be linear in the range of 10(1)-10(5) cfu/mL with a correlation coefficient higher than 0.99. The limit of detection was calculated as 5 cfu/mL. The method was successfully applied to spiked tap and lake water samples. The results suggest that the developed method is applicable for on-site E. coli detection and offers several advantages such as large dynamic range, high sensitivity, high selectivity and short analysis time.