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Microstructure and mechanical properties of AlCuFe eutectic alloy

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Transactions of Nonferrous Metals Society of China 2020年第12期30卷 3183-3194页

作者： Sevda ENGİN Department of Energy Systems Engineering Faculty of TechnologyKütahya Dumlupınar UniversityKütahyaTurkey

In the production of AlCuFe alloy for a special application,the growth rate was changed and the results were *** in the eutectic spacing(microstructure)of a material due to the growth rate are known to affect its mechanical,electrical and thermal *** evaluate its microstructure,the eutectic composition of Al−32.5wt.%Cu−0.5wt.%Fe was prepared and directional solidification experiments were conducted using a Bridgman-type furnace at a constant temperature gradient(G=8.50 k/mm)and five growth rates(V=8.25,16.60,41.65,90.05,164.80μm/s).The effect of the growth rate on the eutectic spacing was then determined,and the resulting microhardness and ultimate tensile strength were obtained based on the change in the microstructure by regression analysis and Hall−Petch *** the fact that the growth rate increased by approximately twenty times,the eutectic spacing decreased by a factor of approximately 5,and these changes in the growth rate and microstructure caused the mechanical properties to change by a factor of approximately 1.5.

关键词： directional solidification aluminum alloy microstructure tensile strength hardness

The C–V and G/ω–V Electrical Characteristics of ^(60)Co γ-Ray Irradiated Al/Si_(3)N_(4)/p-Si (MIS) Structures

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Chinese Physics Letters 2013年第7期30卷 193-197页

作者： S.Zeyrek A.Turan M.M.Bülbül Department of Physics Faculty of Arts and SciencesDumlupınar University43100KütahyaTurkey Department of Physics Faculty of SciencesGazi University06500BeşevlerAnkaraTurkey

The influence of ^(60)Co(γ-ray)irradiation on the electrical characteristics of Al/Si_(3)N_(4)/p-Si(MIS)structures is investigated using capacitance-voltage(C–V)and conductance-voltage(G/ω–V)*** MIS structures are exposed to a ^(60)Coγradiation source at a dose of 0.7 kGy/h,with a total dose range of 0–100 *** C–V and G/ω–V properties are measured before and after ^(60)Coγ-ray irradiation at 500 kHz and room *** is found that the capacitance and conductance values decrease with the increase in the total dose due to the irradiation-induced defects at the *** results also indicate thatγradiation causes an increase in the barrier height ФB,Fermi energy EF and depletion layer width W_(D).The interface state density(N_(ss)),using the Hill–Coleman method and dependent on radiation dose,is determined from the C–V and G/ω–V measurements and decreases with an increase in the radiation *** decrease in the interface states can be attributed to the decrease in the recombination centers and the passivation of the Si surface due to the deposition insulator layer(Si_(3)N_(4)).In addition,it is clear that the acceptor concentration NA decreases with increasing radiation *** profile of series resistance Rs for various radiation doses is obtained from forward and reverse-biased C–V and G/ω–V measurements,and its values decrease with increasing radiation dose,while it increases with increasing voltage in the accumulation region.

关键词： capacitance interface attributed

High seed losses in mountain birch(Betula pubescens ***)and developmental,ecological,and environmental correlates

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Journal of Plant Ecology 2024年第4期17卷 56-69页

作者： Guorun Oskarsdottir Thora E.Thorhallsdottir kristin Svavarsdottir University of Iceland 102 ReykjavíkIceland Land and Forest Iceland ReykjavíkIceland

Plants typically experience great losses from their reproductive potential represented by ovule production to the post-dispersal crop of viable *** examined seed density and viability in a founder population of mountain birch(Betula pubescens ***),aiming to quantify losses at different stages and examine potential selection forces on the reproduction success of the founder generation of an isolated *** the time of the study(2017-2020),the population had recently reached reproductive maturity,following its colonization around 1990 through long-distance dispersal onto an early successional outwash plain in southeast *** densities were high,but 89% of apparently intact seeds did not contain an embryo,despite being visually indistinguishable from filled *** evident losses amounted to about 45% of the total seed crop and were mostly due to predation by the gall midge Semudobia *** all losses were accounted for,2.7% of the seed crop remained viable and *** limitation may partially explain the high incidence of empty *** flower production is compatible with the predator satiation hypothesis but cannot explain pre-dispersal *** adaptation to predation,masting,appears poorly developed in *** results suggest the presence of constraints on the reproduction potential of the new island population,that are more limiting than in neighbouring populations,and we discuss their developmental,ecological,and environmental correlates.

关键词： Betula pubescens ssp.tortuosa(Ledeb.)Nyman Iceland seed quality seed losses Semudobia betulae sub-arctic

Relations between Simplicial Groups, 3-Crossed Modules and 2-Quadratic Modules

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Acta Mathematica Sinica,English Series 2014年第6期30卷 968-984页

作者： Hasan ATk Erdal ULUALAN Department of Mathematics stanbul Medeniyet University Department of Mathematics Dumlup?nar University

In this paper, we define two-quadratic module and explore the relations among two-quadratic modules, three-crossed modules and simplicial groups.

关键词： Simplicial group quadratic module grossed module

The ft values of the superallowed Fermi beta decays

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Science China(Physics,Mechanics & Astronomy) 2013年第4期56卷 718-723页

作者： ALIk Abdullah Engin GEREkLIOGLU Murat SELAM Cevad Department of Physics Faculty of Arts and Sciences Dumlup nar University Kütahya 43100 Turkey Department of Physics Faculty of Science Ege University Bornova zmir 35100 Turkey Department of Physics Faculty of Arts and Sciences Mu Alparslan University Mu 49100 Turkey

In this work, the ft values of the 0+ →0+ superallowed Fermi beta decays have been investigated. In the calculations, the shell model has been modified by Pyatov's restoration method because of the isospin breaking a... 详细信息

关键词： superallowed beta decays Fermi matrix elements ft values

Short term temporal variability of selected organophosphate esters among healthy adults living in the National Capital Region of Canada

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Emerging Contaminants 2024年第3期10卷 293-303页

作者： Shabana Siddique Gong Zhang Rocio Aranda-Rodriguez Leonora Marro Cariton kubwabo Environmental Health Science and Research Bureau Health CanadaOttawaONK1A 0K9Canada

Organophosphate esters(OPEs)are used primarily as flame-retardants and *** are commonly detected in various environmental matrices,food and drinking water,and their metabolites are frequently found and quantified in *** adverse impacts on human health,including carcinogenicity,neurotoxicity,developmental and reproductive toxicity have been well *** concentration of OPE metabolites can vary in the same individual,depending on the sampling time,thus introducing significant uncertainty in exposure *** current study focusses on the assessment of short term temporal variability in adult men and women residing in Canada's Capital *** OPE metabolites were analyzed in 562 daily urine samples,collected every three days for five weeks from 11 *** extraction procedure was performed on an automated SPE and extracts analyzed using UPLC-MS/*** spot urine samples as well as first morning void(FMV),the detection frequency was greater than 50%for bis(2-chloroethyl)hydrogen phosphate(BCEP),bis(1-chloro-2-propyl)phosphate(BCIPP),bis(1,3-dichloro-2-propyl)phosphate(BDCIPP),diphenyl phosphate(DPHP)and bis(2,4-ditert-butylphenyl)hydrogen phosphate(B2,4DtBPP).Significant difference was observed in males and females for BCEP and ***-class correlation coefficient(ICC)for creatinine corrected data for the spot urine samples ranged from 0.37 to *** reproducibility was observed for creatinine corrected DPHP and BCIPP in both spot urine and FMV *** variation was observed between study participants in the spot urine samples when compared to the FMV ***,when considering diurnal difference there was a considerable inter-day variation in the FMV samples compared to the spot *** strength of the study is that the participants belonged to the same geographical location and working in the same facility,hence spatial variability did not influence the outcome of the results.

关键词： Organophosphate esters Flame retardants Plasticizers Temporal variability Canada

Electrical and dielectric properties of Al/p-Si and Al/perylene/p-Si type diodes in a wide frequency range

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Chinese Physics B 2014年第1期23卷 519-524页

作者： Ahmet kaya Sedat Zeyrek Sait Eren San Şmsettin Altındal Opticianry Department Vocational School of Medical Sciences Turgut Ozal University Ankara 06370 Turkey Physics Department Faculty Sciences Dumlupınar University Kütahya 43000 Turkey Physics Department Gebze Institute of Technology Kocaeli 41400 Turkey Physics Department Faculty of Sciences Gazi University Ankara 06500 Turkey

The perylene （C20H12） layer effect on the electrical and dielectric properties of Al/p-Si （MS） and Al/perylene/p-Si （MPS） diodes have been investigated and compared in the frequency range of 0.7 kHz-2 MHz. Experimental results show that C-V characteristics give an anomalous peak for two structures at low frequencies due to interface states （Nss） and series resistance （Rs）. The increases in C and G/o3 at low frequencies confirm that the charges at interface can easily follow an ac signal and yield excess capacitance and conductance. The frequency-dependent dielectric constant （er） and dielectric loss （e＇） are subtracted using C and G/co data at 1.5 V. The eI and e＂ values are found to be strongly dependent on frequency and voltage, and their large values at low frequencies can be attributed to the excess polarization coming from charges at traps. Plots of ln（o＇ac）-ln（w） for two structures have two linear regions, with slopes of 0.369 and 1.166 for MS, and of 0.077 and 1.061 for MPS, respectively. From the C 2-V characteristics, the doping acceptor atom concentration （NA） and barrier height （,~） for Schottky barrier diodes （SBDs） 1.303 ~ 1015 cm-3, and 1.10 and I. 13 eV, respectively. of MS and MPS types are also obtained to be 1.484 ~ 1015

关键词： organic-inorganic based Schottky diodes perylene (C20H12) interfacial layer electrical and di-electric properties frequency and voltage dependence

Nonlinear dynamic modeling of planar moving Timoshenko beam considering non-rigid non-elastic axial effects

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Applied Mathematics and Mechanics(English Edition) 2024年第3期45卷 479-496页

作者： M.ABBASI GAVARI M.R.HOMAEINEZHAD Faculty of Mechanical Engineering K.N.Toosi University of TechnologyTehran 19991-43344Iran

Due to the importance of vibration effects on the functional accuracy of mechanical systems,this research aims to develop a precise model of a nonlinearly vibrating single-link mobile flexible *** manipulator consists of an elastic arm,a rotary motor,and a rigid carrier,and undergoes general in-plane rigid body motion along with elastic transverse *** accurately model the elastic behavior,Timoshenko’s beam theory is used to describe the flexible arm,which accounts for rotary inertia and shear deformation *** applying Newton’s second law,the nonlinear governing equations of motion for the manipulator are derived as a coupled system of ordinary differential equations(ODEs)and partial differential equations(PDEs).Then,the assumed mode method(AMM)is used to solve this nonlinear system of governing equations with appropriate shape *** assumed modes can be obtained after solving the characteristic equation of a Timoshenko beam with clamped boundary conditions at one end and an attached mass/inertia at the *** addition,the effect of the transverse vibration of the inextensible arm on its axial behavior is *** the axial rigidity,the effect makes the rigid body dynamics invalid for the axial behavior of the ***,numerical simulations are conducted to evaluate the performance of the developed model,and the results are compared with those obtained by the finite element *** comparison confirms the validity of the proposed dynamic model for the *** to the mentioned features,this model can be reliable for investigating the system’s vibrational behavior and implementing vibration control algorithms.

关键词： planar moving Timoshenko beam non-rigid non-elastic axial effect as-sumed mode method(AMM) nonlinear motion analysis

Bearing capacity of circular footings on multi-layered sand-waste tire shreds reinforced with geogrids

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第3期16卷 1085-1094页

作者： Mahmoud Ghazavi Ehsan khosroshahi Faculty of Civil Engineering K.N.Toosi University of TechnologyTehranIran

The presence of waste tires poses an environmental challenge as they occupy a significant amount of land and are expensive to dispose in ***,reusing waste tires can address this issue when waste tires are used in geotechnical *** determine the viability of this approach,laboratoryscale tests were conducted to investigate load-bearing capacity of circular footings on sand-tire shred(STS)mixtures with shredded waste tire contents of 5%e15%by weight and three different widths of *** investigation focused on analyzing the thickness of layers composed of STS mixtures,the soil cap,and the impact of geogrids on bearing *** results indicate that a specific mixture of sand and tire shreds provides the highest footing-bearing *** addition,the optimal shred content and size were found to be 10%by weight and 2 cm×10 cm,***,for a given tire shred width,a particular length provides the largest bearing *** results agree well with that of previous research conducted by the first author and his colleagues in direct shear and California bearing ratio(CBR)*** primary finding of this research is that the use of two-layered STS mixtures reinforced by geogrids significantly enhances the bearing capacity.

关键词： Geogrid Sand Waste tire shred Bearing capacity Waste tire shred optimization Tire shred aspect ratio