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Hydrophobic coating of surfaces by plasma polymerization in an RF plasma reactor with an outer planar electrode:synthesis,characterization and biocompatibility

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Plasma Science and Technology 2017年第8期19卷 109-117页

作者： Mustafa KARAMAN Mehmet GüRSOY Fatmanur AYKüL Zahide TOSUN M Demirel KARS H bekir yildiz Department of Chemical Engineering Selcuk University Advanced Technology Research and Application Center Selcuk University Department of Materials Science and Nanotechnology Engineering KTO Karatay University

This paper presents the plasma polymerization of poly（hexafluorobutyl acrylate）（PHFBA） thin films on different substrates in an RF plasma reactor with an outer planar electrode. This reactor configuration allows？large area uniformity and fast processing times. Deposition rates of up to60 nm min-1were observed. The influence？of plasma power and substrate temperature on the？deposition rate, structure and wettability of the as-deposited films was？investigated. It was observed that better hydrophobicity was obtained at high plasma power and in low temperature conditions. PHFBA thin films deposited on electrospun poly（acrylonitrile） fiber mats under such conditions resulted in superhydrophobic surfaces with？contact angle values greater than 150°.In？vitro cell studies using human epithelial cells demonstrated the non-toxic nature of the？plasma-polymerized PHFBA films.

关键词： plasma hydrophobic PECVD polymer biocompatible

New-fashioned solitons of coupled nonlinear Maccari systems describing the motion of solitary waves in fluid flow

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Journal of Ocean Engineering and Science 2024年第4期9卷 353-363页

作者： Tarikul Islam ali Akbar Hadi Rezazadeh Ahmet bekir Department of Mathematics Hajee Mohammad Danesh Science and Technology UniversityDinajpurBangladesh Department of Applied Mathematics University of RajshahiBangladesh Faculty of Modern Technologies Engineering Amol University of Special Modern TechnologiesAmolIran Neighbourhood of Akcaglan Imarli StreetNo.28/4Eskisehir 26030Turkey

The Schrodinger equation type nonlinear coupled Maccari system is a significant equation that flourished with the wide-ranging arena concerning fluid flow and the theory of deep-water waves,physics of plasma,nonlinear optics,*** exploit the enhanced tanh approach and the rational(G/G)-expansion process to retrieve the soliton and dissimilar soliton solutions to the Maccari system in this *** suggested systems of nonlinear equations turn into a differential equation of single variable through executing some operations of wave variable ***,with the successful implementation of the advised techniques,a lot of exact soliton solutions are *** obtained solutions are depicted in 2D,3D,and contour traces by assigning appropriate values of the allied unknown *** diverse graphical appearances assist the researchers to understand the underlying processes of intricate phenomena of the leading *** individual performances of the employed methods are praise-worthy which justify further application to unravel many other nonlinear evolution equations ascending in various branches of science and engineering.

关键词： Rational(G'/G)-expansion method Coupled nonlinear schrodinger equations Soliton Improved tanh method Exact solutions

Effect of Porosity on the Mechanical Properties and Wear Performance of 2% Copper Reinforced Sintered Steel Used in Shock Absorber Piston Production

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Journal of Materials Science & Technology 2009年第5期25卷 577-582页

作者： bekir Yalin Technical Education Faculty Suleyman Demirel University

Powder metallurgy （P/M） method has mainly been used to produce automobile parts such as self-lubrication beds, shock absorber parts, and gear wheels. In order to investigate the effect of porosity on the mechanical and tribological properties in sintered steel, specimens with 10%, 15%, and 20% porosity were produced in a 10 mm×10 mm×55 mm prismatic shape by pre-alloying powders of the MPIF Fe-C-0.205 alloy used in the production of shock absorber pistons. Sintering was carried out at 900℃ for 45 min in an argon atmosphere. Tensile, charpy, and microhardness tests were performed on these specimens. In addition, the wear performance of a 2% Cu reinforced sintered steel alloy under dry sliding conditions was determined. Metallographic studies such as pore formation, worn surface, and fractured surface analyses were performed by scanning electron microscopy and optical microscopy. The results indicate that irregular pore formation tendencies increase with an increase in porosity （%）. Furthermore, an increase in porosity was shown to decrease the mechanical properties and increase the wear trace area and the friction coefficient of sintered steel.

关键词： Shock absorber piston Powder metallurgy Porosity Friction coefficient

Evaluation of new Austrian tunnelling method applied to Bolu tunnel’s weak rocks

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第3期12卷 541-556页

作者： Ebu bekir Aygar Fugro Sial Geosciences Consulting and Engineering Ltd. Cankaya06690AnkaraTurkey

Since the development of the new Austrian tunnelling method(NATM)in the 1960s,this technique has been applied successfully in many ***,opinions of NATM principles emerged till 2000,*** is not a tunnelling method,but an approach covering all general principles of *** investigate the general principles of the NATM,this study focused on tunnelling practises in the Bolu tunnel,and evaluated the conditions under which the NATM practises could be *** Bolu tunnel project was designed following the NATM *** is evident that practises adopted in this tunnel are important with respect to the *** addition,it shows that the solutions to the problems encountered in this tunnel are consistent with the NATM ***,the study determines the ground types of the NATM principles and proposes associated updates.

关键词： Bolu tunnel New Austrian tunnelling method(NATM) Support types

Levels of oxidative stress parameters and the protective effects of melatonin in psychosis model rat testis

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Asian Journal of Andrology 2008年第2期10卷 259-265页

作者： bekir S. Parlaktas Birsen Ozyurt Huseyin Ozyurt Ayten T. Tunc ali Akbas Department of Urology Gaziosmanpasa University School of Medicine Tokat 60100 Turkey Department of Anatomy Gaziosmanpasa University School of Medicine Tokat 60100 Turkey Department of Biochemistry Gaziosmanpasa University School of Medicine Tokat 60100 Turkey Department of Histology and Embryology Gaziosmanpasa University School of Medicine Tokat 60100 Turkey

Aim： To evaluate the effects of melatonin on antioxidant enzyme levels and histopathologic changes in dizocilpine （MK-801）-induced psychosis model rat testis. Methods： A total of 24 adult male Wistar-Albino rats were divided into three groups with 8 in each. Group I was used as control. Rats in Group II were injected with MK-801 （0.5 mg/kg body weight i.p. for 5 days）. In addition to MK-801, melatonin （50 mg/kg body weight i.p. once a day for 5 days） was injected into the rats in Group Ⅲ. The testes were harvested bilaterally for biochemical and histopathological examinations. Antioxidant enzyme activities, malondialdehyde, protein carbonyl and nitric oxide （NO） levels in testicular tissues were analyzed using spectrophotometric analysis methods. Histopathological examinations of the testes were also performed. Results： MK-801 induced testicular damage, which resulted in significant oxidative stress （OS） by increasing the levels of antioxidant enzymes. The malondialdehyde, protein carbonyl and NO levels were increased in testicular tissues of rats. Treatment with melatonin led to significant decrease in oxidative injury. Administration of melatonin also reduced the detrimental histopathologic effects caused by MK-801. Conclusion： The results of the present study showed that MK-801 cause OS in testicular tissues of rats and treatment with melatonin can reduce the harmful effects＇of MK-801. （Asian JAndro12008 Mar; 10： 259-265）

关键词： testis dizocilpine psychosis oxidative stress melatonin antioxidant enzymes

Bright and dark soliton solutions for some nonlinear fractional differential equations

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Chinese Physics B 2016年第3期25卷 52-59页

作者： Ozkan Guner Ahmet bekir Cankiri Karatekin University Faculty of Economics and Administrative Sciences Department of International Trade CankiriTurkey Eskisehir Osmangazi University Art-Science Faculty Department of Mathematics-Computer Eskisehir Turkey

In this work, we propose a new approach, namely ansatz method, for solving fractional differential equations based on a fractional complex transform and apply it to the nonlinear partial space-time fractional modified Benjamin-Bona- Mahoney （mBBM） equation, the time fractional mKdV equation and the nonlinear fractional Zoomeron equation which gives rise to some new exact solutions. The physical parameters in the soliton solutions： amplitude, inverse width, free parameters and velocity are obtained as functions of the dependent model coefficients. This method is suitable and more powerful for solving other kinds of nonlinear fractional PDEs arising in mathematical physics. Since the fractional deriva- tives are described in the modified Riemann-Liouville sense.

关键词： exact solutions ansatz method space-time fractional modified Benjamin-Bona-Mahoney equa-tion time fractional mKdV equation

Evaluation of line brattice length in an empty heading to improve air flow rate at the face using CFD

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International Journal of Mining Science and Technology 2017年第2期27卷 253-259页

作者： Feroze Tariq Genc bekir School of Mining Engineering University of the WitwatersrandJohannesburg 2050South Africa

The effectiveness of line brattice(LB) ventilation system depends on the associated system ***, the effect of these variables on the air flow rates close to the face of the heading is not extensively studied. In this paper, the effect of the LB length in relation to the LB-wall distance on the air flow rate reaching the face is analysed. Scenarios were developed using four LB lengths, two LB-wall distances and two heading depths. These scenarios were simulated with a validated CFD model. The air flow rates and patterns at various locations inside the heading were analysed. This helped to find the minimum LB-face distance that should be maintained for each LB-wall distance to maximise the air flow rate at the face. The minimum length when used will improve ventilation and reduce energy cost.

关键词： Coal mine ventilation Auxiliary ventilation Line brattice ventilation system Computational fluid dynamics

The biochemical effects of ischemia-reperfusion injury in the ipsilateral and contralateral testes of rats and the protective role of melatonin

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Asian Journal of Andrology 2014年第2期16卷 314-318,I0012页

作者： bekir S Parlaktas Dogan Atilgan Huseyin Ozyurt Yusuf Gencten ali Akbas Fikret Erdemir Nihat Uluocak Department of Urology Gaziosmanpasa University Faculty of Medicine Tokat Turkey Department of Biochemistry Gaziosmanpasa University Faculty of Medicine Tokat Turkey.

Testicular torsion （TT） is a serious urologic emergency that is observed in adolescent males and that can lead to infertility if left untreated. The ischemia-reperfusion （I/R） injury due to TT has been implicated in the pathogenesis of testicular damage. We investigated the effects of melatonin on oxidative damage in the ipsUateral and contralateral testes of rats induced by unilateral TT. A total of 21 prepubertal male Wistar albino rats were divided into three groups, each consisting of seven rats, In Group 1 （SHAM group）： a sham operation to the left testis and bilateral orchiectomy were performed. In Group 2 （I/R group）： I/R injury was created by rotating the left testis 720° in a clockwise direction for 2 h and detorsing the testis after 2 h. Group 3 （I/R ＋ MEL group）： rats were subjected to I/R injury and one-shot melatonin injection （50mgkg-1, intraperitoneal （i.p.））. The testes of the rats were excised bilaterally in all groups. The testicular tissue activities of antioxidant catalase （CAT）, superoxide dismutase （SOD） and glutathione peroxidase enzymes （GSH-Px）, and the tissue levels of malondialdehyde （MDA）, protein carbonyl （PC） and nitric oxide （NO） were determined. Administration of melatonin caused a significant decrease in lipid peroxidation and enzyme activities in the ipsilateral testis when compared with the control group （P 〈 0.05）. All of the changes in the enzyme activities of the contralateral testis were insignificant （P 〉 0.05）. MDA levels were significantly altered in the contralateral testis （P = 0.009）, Melatonin administration decreased the deleterious effects of I/R injury in the ipsilateral torted testes of the rats. The contralateral testes were slightly affected by unilateral TT.

关键词： antioxidant enzymes ischemia-reperfusion (I/R) lipid peroxidation melatonin testicular torsion {TT)

Applications of the first integral method to nonlinear evolution equations

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Chinese Physics B 2010年第8期19卷 24-27页

作者： Filiz Tascan Ahmet bekir Eskisehir Osmangazi University Art-Science FacultyDepartment of MathematicsEskisehir-TüRKIYE

In this paper, we establish travelling wave solutions for some nonlinear evolution equations. The first integral method is used to construct the travelling wave solutions of the modified Benjamin-Bona-Mahony and the coupled Klein-Gordon equations. The obtained results include periodic and solitary wave solutions. The first integral method presents a wider applicability to handling nonlinear wave equations.

关键词： travelling wave solutions first integral method modified Benjamin-Bona-Mahony equa- tion coupled Klein-Gordon equation