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Alternating-current losses in two-layer superconducting cables consisting of second-generation superconductors coated by U-shaped ferromagnetic materials

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Chinese Physics B 2013年第12期22卷 509-513页

作者： ahmet Cicek Fedai Inanir Fedor Gmry Department of Physics Faculty of Arts and Sciences Mehmet Akif Ersoy University Department of Physics Faculty of Arts and Sciences Recep Tayyip Erdog an University Institute of Electrical Engineering Slovak Academy of Sciences Du'bravska' Cesta 9 842 39 Bratislava Slovakia

Alternating-current losses in a two-layer superconducting cable, each layer being composed of 15 closely-spaced rectangular wires made up of second-generation superconductors when the ends of wires are coated by either a non-magnetic or strong ferromagnetic material having a U profile is numerically investigated. Computations are carried out through the finite-element method. The alternating-current losses do not increase significantly if the relative permeability of the coating is increased three orders of magnitude, provided that the current amplitude is less than half of the critical current in a superconducting wire. However, the losses are much higher for ferromagnetic coating if the amplitude of the applied current oscillating at 50 Hz is close to the critical current. The ferromagnetic coating is seen to accumulate the magnetic field lines normally on its surfaces, while the field lines are parallel to the long axes of the wires, leading to more significant flux penetration in the coated regions. This facilitates a uniform low-loss current flow in the uncoated regions of the wires. In contrast, coating with a non-magnetic material gives rise to a considerably smaller current flow in the uncoated regions, whereas the low-loss flow is maintained in the coated regions. Moreover, the current flows in opposite directions in the coated and uncoated regions, where the direction in each region is converse for the two materials.

关键词： second-generation superconductor two-layer cable ferromagnetic coating U profile alternating-current losses

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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

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On the Use of Nanofluids in Solar Energy Applications

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Journal of Thermal Science 2020年第3期29卷 513-534页

作者： CUCE Erdem CUCE Pinar Mert GUCLU Tamer BESIR ahmet Burhaneddin Department of Mechanical Engineering Faculty of EngineeringRecep Tayyip Erdogan UniversityZihni Derin Campus53100 RizeTurkey Low/Zero Carbon Energy Technologies Laboratory Faculty of EngineeringRecep Tayyip Erdogan UniversityZihni Derin Campus53100 RizeTurkey Department of Energy Systems Engineering Faculty of EngineeringRecep Tayyip Erdogan UniversityZihni Derin Campus53100 RizeTurkey

Renewable energy technologies are in the centre of interest to narrow the gap between fossil fuels and clean energy *** dominant role of solar energy systems among the alternatives is beyond question owing to being associated with an infinite energy source,well-documented theory,simplicity,eco-friendly structure and notably higher energy and exergy efficiency range compared to other ***,in solar energy systems,conventional working fluids with poor thermophysical properties are still *** other words,further improvements are still available in the said systems by the use of unique nanoparticles with superior thermal,electrical,optical and mechanical *** the scope of this research,the applications of nanofluids in various solar energy systems such as tracking and non-tracking solar collectors,photovoltaic/thermal systems,solar thermoelectric devices,solar stills,solar thermal energy storage systems,solar greenhouses and solar ponds are comprehensively *** comparisons and discussions are proposed for the potential impacts of various nanofluids on coefficient of performance(COP)and thermodynamic performance figures of solar energy systems such as energy and exergy efficiency,effectiveness and *** challenges of nanofluids are also addressed which need to be resolved in further works.

关键词： nanofluids solar energy applications thermal and electrical performance COP cost

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Assessing fire severity in Turkey's forest ecosystems using spectral indices from satellite images

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林业研究:英文版 2023年第6期34卷 1747-1761页

作者： Coşkun Okan Güney ahmet Mert Serkan Gülsoy Department of Forest Fires Aegean Forestry Research Institute35430 IzmirTurkey Department of Wildlife Ecology and Management Faculty of ForestryIsparta University of Applied Science32260 IspartaTurkey Department of Soil Science and Ecology Faculty of ForestryIsparta University of Applied Science32260 IspartaTurkey

Fire severity classifications determine fire damage and regeneration potential in post-fire areas for effective implementation of restoration *** fire damage varies according to vegetation and fire characteristics,regional assessment of fire severity is *** objectives of this study were:(1)to test the performance of different satellite imagery and spectral indices,and two field—measured severity indices,CBI(Composite Burn Index)and GeoCBI(Geometrically structured Composite Burn Index)to assess fire severity;(2)to calculate classification thresholds for spectral indices that performed best in the study areas;and(3)to generate fire severity maps that could be used to determine the ecological impact of forest *** large fires in Pinus brutia(Turkish pine)and Pinus nigra *** ***(Anatolian black pine)—dominated forests during 2020 and 2021 were selected as study *** results show that GeoCBI provided more reliable estimates of field—measured fire severity than *** Sentinel-2 and Landsat-8/OLI images performed similarly well,MODIS performed *** severity classification thresholds were determined for Sentinel-2 based RdNBR,dNBR,dSAVI,dNDVI,and dNDMI and Landsat-8/OLI based dNBR,dNDVI,and *** several spectral indices,the highest accuracy for fire severity classification was found for Sentinel-2 based RdNBR(72.1%)and Landsat-8/OLI based dNBR(69.2%).The results can be used to assess and map fire severity in forest ecosystems similar to those in this study.

关键词： Remote sensing Forest fire Fire severity Spectral indices Composite burn index

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Time to give up traditional methods for the management of gastrointestinal neuroendocrine tumours

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World Journal of Clinical Cases 2021年第29期9卷 8627-8646页

作者： ahmet Yozgat Murat Kekilli Mustafa Altay Department of Gastroenterology Ufuk UniversityAnkara06510Turkey Department of Gastroenterology Gazi UniversityAnkara 06560Turkey Department of Endocrinology and Metabolism University of Health Sciences TurkeyKeçiören Health Administration and Research CenterAnkara 06190Turkey

Neuroendocrine tumors(NETs)are a rare and heterogeneous disease group and constitute 0.5%of all *** annual incidence of NETs is increasing *** reason for the increase in the incidence of NETs is the detection of benign lesions,incidental detection due to the highest use of endoscopic and imaging procedures,and higher recognition rates of *** have been exciting developments regarding NET biology in recent *** these,first of all,somatostatin receptors and downstream pathways in neuroendocrine cells have been found to be important regulatory mechanisms for protein synthesis,hormone secretion,and ***,activation of the mammalian target of rapamycin pathway was found to be an important mechanism in angiogenesis and tumor survival and cell ***,the importance of proangiogenic factors(platelet-derived growth factor,vascular endothelial growth factor,fibroblastic growth factor,angiopoietin,and semaphorins)in the progression of NET has been *** the combination of biomarkers and imaging methods allows early evaluation of the appropriateness of treatment and response to treatment.

关键词： Enterochromaffin cells 68Ga-DOTATATE Gastrointestinal Neuroendocrine tumours Somatostatin receptor Targeted peptide receptor radiotherapy

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Different accelerated corneal collagen cross-linking treatment modalities in progressive keratoconus

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Eye and Vision 2019年第1期6卷 114-122页

作者： ahmet Kirgiz Mustafa Eliacik Yusuf Yildirim Department of Ophthalmology University of Health SciencesBagcilar Training and Research HospitalIstanbulTurkey Department of Ophthalmology Istanbul Medipol UniversityIstanbulTurkey University of Health Sciences Beyoglu Eye Training and Research HospitalIstanbulTurkey

Background:To compare the outcomes of two different protocols of accelerated corneal crosslinking(CXL)on visual,corneal high order aberrations(HOA)and topographic parameters in patients with progressive ***:In this prospective comparative study,sixty-six eyes of 66 patients with progressive keratoconus were divided into two groups;37 eyes in Group 1 received 18 mW/cm^(2) for five minutes,and 29 eyes in Group 2 were treated with 9 mW/cm^(2) for 10 *** uncorrected distant visual acuity(UCVA),best-corrected distant visual acuity(BCVA),corneal HOAs and topography parameters were measured preoperatively and postoperatively at the end of 12 *** data for the two groups were compared ***:The mean UCVA and BCVA were significantly improved at the postoperative 12 months compared with the preoperative values in both groups(P<0.05 for all).A significant improvement in corneal HOAs was observed in both groups(P<0.05 for all).The change in corneal coma value was significantly higher in Group 2(P<0.05).The change in keratometric values K1,K2,AvgK and maximum keratometry(AKf)were significantly higher in Group 2(P<0.05 for all).The regression model showed that the most important factor predicting the change in AKf was the type of CXL(β=−0.482,P=0.005).Conclusions:Accelerated CXL using 10 min of UVA irradiance at 9 mW/cm^(2) showed better topographic improvements and coma values than five minutes of UVA irradiance at 18 mW/cm^(2) independent of keratoconus severity.

关键词： Accelerated crosslinking Corneal collagen CXL High order aberrations Keratoconus Topography

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Comparison of phenolic components and biological activities of two Centaurea *** by three extraction techniques

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Asian Pacific Journal of Tropical Medicine 2017年第6期10卷 669-676页

作者： Sevil Albayrak Bayram Atasagun ahmet Aksoy Erciyes University Science FacultyDepartment of Biology38039 KayseriTurkey Akdeniz University Science FacultyDepartment of Biology07058 AntalyaTurkey

Objective: The present study aimed to compare the polyphenol content, total phenolic, total flavonoid, antioxidant and antimicrobial activity of the extracts obtained from Centaurea amaena Boiss. & Balansa and Centaurea aksoyi Hamzao?lu & Budak. Methods: Both species were subjected to maceration, Soxhlet and ultrasonication extractions with methanol in order to macerated(ME), Soxhlet(SE) and ultrasonicated(UE) extracts. Their phenolic profiles were qualitatively examined by LC-MS. Their antioxidant activities were determined by phosphomolybdenum, β-carotene bleaching and DPPH assays. Agar diffusion and broth dilution methods were carried out to find the antimicrobial activity of these extracts against fifteen microorganisms. Results: Quercetin, quercetin-3-β-D-glucoside and protocatechuic acid were the main components of the both extracts obtained by Soxhlet extraction. The highest phenolic and flavonoid contents were found in the UE for both species. All the extracts exhibited good total antioxidant and DPPH radical scavenging activity. UE obtained from C. amaena showed the highest antioxidant activity with the highest phenolic and flavonoid contents. The antibacterial activity of UE obtained from C. amaena was better than other extracts and antibacterial activity of C. amaena was also better than C. aksoyi. Discussion: This study confirms that ultrasonic extraction may be an ideal, simple and rapid method to obtain polyphenol-rich extracts have antioxidant as well as antibacterial activity from both Centaureaspecies especially from C. amaena.

关键词： Centaurea aksoyi Centaurea amaena LC-MS Antioxidant activity Antimicrobial activity

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Elastic line deformed on a pseudo-hypersurface by an external field in pseudo-Euclidean spaces

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Science China Mathematics 2008年第2期51卷 233-240页

作者： YCESAN ahmet KEN A.Ceylan Department of Mathematics Süleyman Demirel University32260 IspartaTurkey

We derive intrinsic formulation for elastic line deformed on a pseudo-hypersurface by an external field in the pseudo-Euclidean spaces E_v^*** formulation determines elastic line deformed on a pseudo-hypersurface.

关键词： elastic line pseudo-Euclidean spaces intrinsic formulation external field 53A35 53B30 74M30

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Synthesis, Spectroscopic and Electrochemical Investigations of Two vic-Dioximes and Their Mononuclear Ni（Ⅱ）, Cu（Ⅱ） and Co（Ⅱ） Metal Complexes Containing Morpholine Group

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Chinese Journal of Chemistry 2006年第11期24卷 1599-1604页

作者： KILIC, ahmet TAS, Esref GUMGUM, Bahattin YILMAZ, Ismail Department of Chemistry Harran University Sanliurfa 63510 Turkey Department of Chemistry Dicle University Diyarbakir 21280 Turkey Department of Chemistry Technical University oflstanbul Istanbul Maslak 34469 Turkey

Two vic-dioxime ligands （LxH2） containing morpholine group have been synthesized from 4-[2-（dimethylaminoethyl）] morpholine with anti-phenylchloroglyoxime or anti-monochloroglyoxime in absolute THF at -15 ℃. Reaction of two vic-dioxime ligands with MCl2·nH2O （M： Ni, Cu or Co and n=2 or 6） salts in 1 ： 2 molar ratio afforded metal complexes of type [M（LxH）2] or [M（LxH）2·2H2O]. All of metal complexes are non-electrolytes as shown by their molar conductivities （Am） in DMF （dimethyl formamide） at 10^-3 mol·L^-1. Structures of the ligands and metal complexes have been solved by elemental analyses, FT-IR, UV-Vis, ^1H NMR and ^13C NMR, magnetic susceptibility measurements, molar conductivity measurements. Furthermore, redox properties of the metal complexes were investigated by cyclic voltammetry.

关键词： morpholine electrochemistry dioxime structure metal complex cyclic voltammetry

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Basin-wide hydrological system assessment under climate change scenarios through conceptual modelling

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International Journal of Digital Earth 2020年第8期13卷 915-938页

作者： Cenk Donmez Suha Berberoglu ahmet Cilek Peter Krause Division of Remote Sensing and GIS Department of Landscape ArchitectureFaculty of ArchitectureUniversity of CukurovaAdanaTurkey Thuringian State Institute for Environment and Geology JenaGermany

Mediterranean region is identified as a primary hot-spot for climate change due to the expected temperature and rainfall *** the potential impacts of climate change on the hydrology in these regions is an important task to develop long-term water management *** aim of this study was to quantify the potential impacts of the climate changes on local hydrological quantities at the Goksu Watershed at the Eastern Mediterranean,Turkey as a case study.A set of Representative Concentration Pathways(RCP)scenarios were used as drivers for the conceptual hydrological model J2000 to investigate how the hydrological system and the underlying processes would respond to projected future climate *** model was implemented to simulate daily hydrological quantities including runoff generation,Actual Evapotranspiration(AET)and soil-water balance for present(2005–2015)and future(up to 2100).The results indicated an increase of both precipitation and runoff throughout the region from January to *** region showed a strong seasonally dependent runoff regime with higher flows during winter and spring and lower flows in summer and *** study provides a comparative methodology to include meteorological-hydrological modelling integration that can be feasible to assess the climate change impacts in mountainous regions.

关键词： Hydrological modelling RCP climate change Mediterranean watershed

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