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Journal of Modern Power Systems and Clean Energy 2019年第1期7卷 186-199页

作者： Taha Nurettin GüCIN Muhammet BIBEROGLU bekir FINCAN Energy Systems Engineering Department University of Yalova Electrical Engineering Department Istanbul Technical University

This paper proposes a design and control approach to parallel resonant converter(PRC) based battery *** proposed approach is particularly suitable for the constant-current constant-voltage(CC-CV)charging method, which is the most commonly utilized *** the PRC is operated at two different frequencies for each CC and CV charging modes, this approach eliminates the need for complicated control techniques such as the frequency-control and *** proposed method not only simplifies the design and implementation processes of the converter unit but also simplifies the design of output filter configuration and decreases the number of the required components for the control of the *** proposed method is confirmed by two experimental *** results show that the designed charger circuit ensured a very stable constant current in CC charging phase, where the charging current is fixed to 1.75 *** a voltage increase in CV phase is observed, the charger circuit is able to decrease the charging current to 0.5 A in CV phase, as depicted in battery *** efficiency of the charger is figured out to be in the range of 86%-93% in the first setup, while it is found to be in the range of 78%-88% in the second setup,where a high frequency transformer is employed.

关键词： Resonant converter Parallel resonant converter Battery charger Constant-current constant-voltage(CC-CV)charging

ELECTRORHEOLOGY AND CREEP-RECOVERY BEHAVIOR OF CONDUCTING POLYTHIOPHENE/POLY(OXYMETHYLENE)-BLEND SUSPENSIONS

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Chinese Journal of Polymer Science 2012年第1期30卷 16-25页

作者： Ozlem Erol H.Ibrahim Unal bekir Sari Smart Materials Research Lab Chemistry Department Gazi UniversityAnkaraTurkey

Electrorheological properties and creep-recovery behavior of polythiophene/polyoxymethylene-blend having PT（50%）/POM（50%） composition were *** size,conductivity and dielectric values were measured to be 24.77μm,3.85×10^（-5） S·m^（-1） and 26.75,*** ratio was measured to be 64%at the end of 16 *** effects of dispersed particle volume fraction,external electric field strength,shear rate,frequency and temperature on ER properties and storage modulus of PT/POM-blend/silicone oil（SO） suspensions were *** were observed in the electric field viscosities of the suspensions and thus they were classified as a smart *** thinning non-Newtonian viscoelastic behavior was determined for PT/POM-blend/SO ***,time-dependent deformation was examined by creep-recovery tests and recoverable viscoelastic deformation established.

关键词： Conducting polythiophene/poly(oxymethylene) Blends Electrorheogical fluids Creep-recovery behavior

Dark Soliton Solutions of Space-Time Fractional Sharma–Tasso–Olver and Potential Kadomtsev–Petviashvili Equations

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Communications in Theoretical Physics 2017年第2期67卷 182-188页

作者： Ozkan Guner Alper Korkmaz Ahmet bekir Cankiri Karatekin University Department of International Trade Cankiri 18200 Turkey ankiri Karatekin University Department of Mathematics Cankiri 18200 Turkey Eskisehir Osniangazi University Department of Mathematics & Computers Eskisehir 26200 Turkey

Dark soliton solutions for space-time fractional Sharma–Tasso–Olver and space-time fractional potential Kadomtsev–Petviashvili equations are determined by using the properties of modified Riemann–Liouville derivative and fractional complex transform. After reducing both equations to nonlinear ODEs with constant coefficients, the tanh ansatz is substituted into the resultant nonlinear ODEs. The coefficients of the solutions in the ansatz are calculated by algebraic computer computations. Two different solutions are obtained for the Sharma–Tasso–Olver equation as only one solution for the potential Kadomtsev–Petviashvili equation. The solution profiles are demonstrated in 3D plots in finite domains of time and space.

关键词： exact solution modified Riemann–Liouville derivative space-time fractional Sharma–Tasso–Olver equation space-time fractional potential Kadomtsev–Petviashvili equation

Self-sufficient Cytochrome P450s and their potential applications in biotechnology

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Chinese Journal of Chemical Engineering 2021年第2期34卷 121-135页

作者： bekir Engin Eser Yan Zhang Li Zong Zheng Guo Department of Engineering Faculty of Technical SciencesAarhus UniversityDenmark Key Laboratory for Molecular Enzymology and Engineering The Ministry of EducationSchool of Life ScienceJilin UniversityChangchun 130021China

Cytochrome P450s(CYPs)are ubiquitously found in all kingdoms of life,playing important role in various biosynthetic pathways as well as degradative pathways;accordingly find applications in a vast variety of areas from organic synthesis and drug metabolite production to modification of biomaterials and ***,CYPs catalyze chemically challenging CAH and CAC activation reactions using a reactive high-valent iron-oxo intermediate generated upon dioxygen activation at their heme center,while the other oxygen atom is reduced to the level of water by electrons provided through a reductase partner ***-sufficient CYPs,encoding their heme domain and reductase protein in a single polypeptide,facilitate increased catalytic efficiency and render a less complicated system to work *** self-sufficient CYP enzyme from CYP102A family(CYP102A1,BM3)is among the earliest and most-investigated model enzymes for mechanistic and structural studies as well as for biotechnological *** increasing number of self-sufficient CYPs from the same CYP102 family and from other families have also been reported in last *** this review,we introduce chemistry and biology of CYPs,followed by an overview of the characteristics of self-sufficient CYPs and representative *** engineering efforts leading to novel self-sufficient CYP variants that can catalyze synthetically useful natural and non-natural(nature-mimicking)reactions are ***,the strategy and efforts that aim to circumvent the challenges for improved thermostability,regio-and enantioselectivity,and total turnover number;associated with practical use of self-sufficient CYPs are reviewed.

关键词： Biocatalysis Heme enzymes CAH activation Cytochrome P450s Self-sufficient P450s P450 BM3

Effects of slag fineness on durability of mortars

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第11期8卷 1725-1730页

作者： TOPU lker bekir BLR Turhan Department of Civil Engineering Eski■ehir Osmangazi University Eski■ehir 26480 Turkey

In recent years, the usages of by-products and wastes in industry have become more important. The importance of the sustainable development is also of increasing. The utilizations of wastes, as mineral admixture or fine aggregate, reduce the consumption of the natural resources and improve the durability of concrete. In this study, the effect of the fineness on the high temperature and sulphate resistances of concrete mortar specimens, produced with ground granulated blast-furnace slag (GBFS) replacing cement, is investigated. The compressive and flexural strength test results for all series related to durability effects, exposing temperature and solutions, exposure times for these durability effects, slag content and fineness are discussed. Conse- quently, the optimum slag contents are determined for producing the sulphate and high temperature resistant mortars.

关键词： Cement Fineness Ground slag High temperature effect Sulphate attack Sustainable development

Solving Space-Time Fractional Differential Equations by Using Modified Simple Equation Method

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Communications in Theoretical Physics 2016年第5期65卷 563-568页

作者： Melike Kaplan Arzu Akbulut Ahmet bekir Eskisehir Osmangazi University Art-Science Faculty Department of Mathematics-Computer

In this article,we establish new and more general traveling wave solutions of space-time fractional Klein–Gordon equation with quadratic nonlinearity and the space-time fractional breaking soliton equations using the modified simple equation *** proposed method is so powerful and effective to solve nonlinear space-time fractional differential equations by with modified Riemann–Liouville derivative.

关键词： symbolic computation exact solution space-time fractional differential equation space-time fractional Klein–Gordon equation the space-time fractional breaking soliton equations

Fatty acid hydratase for value-added biotransformation:A review

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Chinese Journal of Chemical Engineering 2020年第8期28卷 2051-2063页

作者： Yan Zhang bekir Engin Eser Peter Kristensen Zheng Guo Department of Engineering Faculty of Science and TechnologyAarhus UniversityGustav wieds vej 108000 AarhusDenmark Faculty of Engineering and Science Department of Chemistry and BioscienceAalborg University9220 AalborgDenmark

The synthesis of hydroxy fatty acids(HFAs) from renewable oil feedstock by addition of water onto C_C bonds has attracted great attention in recent years. Given that selective asymmetric hydration of non-activated C_C bonds has been proven difficult to achieve with chemical catalysts, enzymatic catalysis by fatty acid hydratases(FAHs) presents an attractive alternative approach to produce value-added HFAs with high regio-, enantioand stereospecificity, as well as excellent atom economy. Even though FAHs have just been investigated as a potential biocatalyst for a decade, remarkable information about FAHs in different aspects is available;however, a comprehensive review has not been archived. Herein, we summarize the research progresses on biochemical characterization, structural and mechanistic determination, enzyme engineering, as well as biotechnological application of FAHs. The current challenges and opportunities for an efficient utilization of FAHs in organic synthesis and industrial applications are critically discussed.

关键词： Hydroxy fatty acids Fatty acid hydratases Enzyme characterization Catalytic mechanism Enzyme engineering Biotransformation

Explicit solutions of nonlinear wave equation systems

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Chinese Physics B 2013年第1期22卷 39-45页

作者： Ahmet bekir Burcu Ayhan M. Naci zer Mathematics and Computer Science Department Eskisehir Osmangazi University

We apply the （G＇/G）-expansion method to solve two systems of nonlinear differential equations and construct traveling wave solutions expressed in terms of hyperbolic functions, trigonometric functions, and rational functions with arbitrary parameters. We highlight the power of the （G＇/G）-expansion method in providing generalized solitary wave solutions of different physical structures. It is shown that the （G＇/G）-expansion method is very effective and provides a powerful mathematical tool to solve nonlinear differential equation systems in mathematical physics.

关键词： (G'/G)-expansion method long-short-wave interaction system coupled integrable dispersionless system

Linear and Nonlinear Optical Properties in Spherical Quantum Dots

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Communications in Theoretical Physics 2010年第6期53卷 1185-1189页

作者： Yusuf Yakar bekir Cakir Ayhan Ozmen Physics Department Faculty of Science and Letters Aksaray University Physics Department Faculty of Science Selcuk University

We calculate the energy eigenvalues and the sate functions of one-electron Quantum Dot （QD） by using a combination of Quantum Genetic Algorithm （QGA） and Hartre-Fock-Roothaan （HFR） method. The linear and the third-order nonlinear optical absorption coefficients for the 1s-1p, 1p-1d, and 1d-1f transitions are examined as a function of the incident photon energy for three different values of the stoichiometric ratio. The results show that the stoichiometric ratio, impurity, relaxation time, and dot size have great influence on the optical absorption coefficients of QDs.

关键词： optical properties spherical quantum dot QGA and HFR method

Interaction properties of solitons for a couple of nonlinear evolution equations

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Chinese Physics B 2021年第1期30卷 185-190页

作者： Syed Tahir Raza Rizvi Ishrat Bibi Muhammad Younis Ahmet bekir Department of Mathematics COMSATS University IslamabadLahore CampusPakistan Punjab University College of Information Technology University of the PunjabLahorePakistan Neighbourhood of Akcaglan Imarli Street Number 28/426030EskisehirTurkey

We study one-and two-soliton solutions for the Cahn–Allen(CA) equation and the Brethorton equation. The CA equation has broad spectrum of applications especially in anti-phase boundary motion and it is used in phase-field *** the Brethorton equation is a model for dispersive wave systems, it is used to find the resonant nonlinear interaction among three linear modes. We use the Hirota bilinear method to obtain one-and two-soliton solutions to the CA equation and the Brethorton equation.

关键词： Hirota bilinear method soliton interaction evolution equations