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Electronic structure calculations of rare-earth intermetallic compound YAg using ab initio methods

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Journal of Rare Earths 2009年第4期27卷 664-666页

作者： S.ugur g.ugur F.Soyalp R.Ellialt1oglu Department of Physics Gazi University Teknikokullar Ankara 06500 Turkey Department of Physics Yüzüncü Yll University Zeve Kampüsü Van 65080 Turkey Department of Physics Engineering Hacettepe University Beytepe Ankara 06800 Turkey

The structural, elastic and electronic properties of YAg-B2（CsCl） were investigated using the first-principles calculations. The energy band structure and the density of states were studied in detail, including partial density of states （PDOS）, in order to identify the character of each band. The structural parameters （lattice constant, bulk modulus, pressure derivative of bulk modulus） and elastic constants were also obtained. The results were consistent with the experimental data available in the literature, as well as other theoretical results.

关键词： YAg electronic band structure density of states elastic constants ab initio rare earths

Structural,electronic and elastic properties of YCu from first principles

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Journal of Rare Earths 2009年第4期27卷 661-663页

作者： g.ugur M.ivi S.ugur F.Soyalp R.Ellialt1oglu Department of Physics Gazi University Teknikokullar Ankara 06500 Turkey Department of Physics Yüzüncü Yll University Zeve Kampüsü Van 65080 Turkey Department of Physics Engineering Hacettepe University Beytepe Ankara 06800 Turkey

The structural, electronic and elastic properties of YCu compound in the B2 （CsCl） phase were investigated using the density functional theory （DFT） within the generalized gradient approximation （ggA）. The electronic density of states （DOS） obtained in this way accorded weU with the results of a recent study utilizing the full-potential linearized augmented plane wave （FLAPW） method. We also found that the density of d-states at the Fermi energy was low. The calculated equilibrium properties such as lattice constant, bulk modulus and its first derivative, and the elastic constants were in good agreement with experimental and theoretical results.

关键词： YCu, electronic band structure, density of states, elastic constants, bulk modulus, ab initio rare earths

Discussion on "Thermomagnetic viscoelastic responses in a functionally graded hollow structure"

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Acta Mechanica Sinica 2012年第3期28卷 911-912页

作者： ugur güven Department of Mechanical Engineering Yildiz Technical University34349 BesiktasIstanbul-Turkey

Allam and Tantawy [1] presented an analytical solu- tion for stress distribution and perturbations of the magnetic field vector in FgM hollow structures made from viscoelas- tic composite materials .While studying thi... 详细信息

关键词： Discussion on Thermomagnetic viscoelastic responses in a functionally graded hollow structure Maxwell FgM

THE EFFECT OF BILINEAR BEHAVIOUR ON THE DIRECTION AND MAgNITUDE OF THE PEELINg MOMENT IN A BI-MATERIAL BEAM

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Acta Mechanica Solida Sinica 2011年第6期24卷 506-509页

作者： ugur gven Yildiz Technical University Department of Mechanical Engineering

In this work a bi-material beam exhibiting partly bilinear behaviour under a uniform temperature change is analyzed. The essence of solution is based on the approach of Timoshenko＇s mechanics of materials, The main aim of the present analysis is to understand the effect of the bilinear behaviour on the peeling moment. This theoretical mechanics model mentioned here can give us useful insights to improve the resistance against the delamination.

关键词： peeling moment layered structures interface thermo mechanical delamination

Optoelectronic and thermoelectric properties of Zintl YLi_(3)A_(2)(A = Sb,Bi) compounds through modified Becke-Johnson potential

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Chinese Physics B 2016年第10期25卷 428-435页

作者： T Seddik g.ugur R Khenata S ugur F Soyalp g Murtaza D P Rai A Bouhemadou S Bin Omran Department of Physics and Astronomy College of ScienceKing Saud UniversityP.O.Box 2455Riyadh 11451Saudi Arabia

In the present work,we investigate the structural,optoelectronic and thermoelectric properties of the YLi3X2(X = Sb,Bi) compounds using the full potential augmented plane wave plus local orbital(FP-APW+lo) *** exchangecorrelation potential is treated with the generalized gradient approximation/local density approximation(ggA/LDA) and with the modified Becke-Johnson potential(TB-mBJ) in order to improve the electronic band structure *** addition,the estimated ground state properties such as the lattice constants,external parameters,and bulk moduli agree well with the available experimental *** band structure calculations with ggA and LDA predict that both compounds have semimetallic ***,the band structure calculations with the ggA/TB-mBJ approximation indicate that the ground state of the YLi3Sb2compound is semiconducting and has an estimated indirect band gap(Γ-L) of about 0.036 eV while the ground state of YLi3Bi2compound is *** the LDA/TB-mBJ calculations indicate that both compounds exhibit semiconducting characters and have an indirect band gap(Γ-L) of about 0.15 eV and 0.081 eV for YLi3Sb and ***,the optical properties reveal strong responses of the herein materials in the energy range between the IR and extreme UV *** properties such as thermal conductivity,electrical conductivity,Seebeck coefficient,and thermo power factors are also calculated.

关键词： Zintl compounds TB-mBJ electronic band-structure optical properties thermoelectric properties

Influences of 2.5wt%Mn addition on the microstructure and mechanical properties of Cu-Al-Ni shape memory alloys

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International Journal of Minerals,Metallurgy and Materials 2010年第2期17卷 192-198页

作者： ugur Sari Department of Computer Education and Instructional Technology Faculty of EducationKinkkale University

The influences of 2.5wt%Mn addition on the microstructure and mechanical properties of the Cu-11.9wt%Al-3.8wt%Ni shape memory alloy（SMA） were studied by means of scanning electron microscopy（SEM）,transmission electron microscopy（TEM）,and differential scanning calorimeter（DSC）.The experimental results show that Mn addition influences considerably the austenite-martensite transformation temperatures and the kind of martensite in the Cu-Al-Ni *** martensitic transformation changes from a mixedβ1→β＇1＋γ＇1 transformation to a singleβ1→β＇1 martensite transformation together with a decrease in transformation *** addition,the observations reveal that the grain size of the Cu-Al-Ni alloy can be controlled with the addition of 2.5wt%Mn and thus its mechanical properties can be *** Cu-Al-Ni-Mn alloy exhibits better mechanical properties with the high ultimate compression strength and ductility of 952 MPa and 15%,*** improvements are attributed to a decrease in grain ***,the hardness decreases from Hv 230 to Hv 140 with the Mn addition.

关键词： Cu-Al-Ni shape memory alloys martensitic transformations grain size mechanical properties.

Evolution of Structural and Magnetic Properties of BaFe12O19 with B2O3 Addition

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Chinese Physics Letters 2010年第11期27卷 177-180页

作者： ugur Topal Nationai Metrology Institute Tubitak UME P.K. 54 Gebze 41470-Kocaeli Turkey

We investigate the effects of B2O3 addition on structural and magnetic properties of hard magnetic BaFe12O19 particles. The conventional solid state reaction method is used as the synthesis route. Single phase BaFe12O19 could be synthesized with very small amounts of B2O3 addition and with calcination at low temperatures （850°C） in short times （1 h）. B2O3 addition also improves the magnetic parameters significantly. Remanence magnetization and specific magnetization at 1.5 T increase by ～40% in magnitude although no significant variations on coercivity is observed.

关键词： Condensed matter: electrical magnetic and optical Nanoscale science and low-D systems Condensed matter: structural mechanical & thermal

Stepping up after spinal cord injury:negotiating an obstacle during walking

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Neural Regeneration Research 2025年第7期20卷 1919-1929页

作者： Alain Frigon Charly g.Lecomte Department of Pharmacology-Physiology Faculty of Medicine and Health SciencesUniversitéde SherbrookeCentre de recherche du Centre Hospitalier Universitaire de SherbrookeSherbrookeQCCanada

Every day walking consists of frequent voluntary modifications in the gait pattern to negotiate *** spinal cord injury,stepping over an obstacle becomes *** over an obstacle requires sensorimotor transformations in several structures of the brain,including the parietal cortex,premotor cortex,and motor *** information and planning are transformed into motor commands,which are sent from the motor cortex to spinal neuronal circuits to alter limb trajectory,coordinate the limbs,and maintain *** spinal cord injury,bidirectional communication between the brain and spinal cord is disrupted and animals,including humans,fail to voluntarily modify limb trajectory to step over an ***,in this review,we discuss the neuromechanical control of stepping over an obstacle,why it fails after spinal cord injury,and how it recovers to a certain extent.

关键词： biomechanics locomotion neurophysiology obstacle negotiation spinal cord injury

Comparison of intravitreal anti-vascular endothelial growth factor agents and treatment results in Irvine-gass syndrome

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International Journal of Ophthalmology(English edition) 2020年第10期13卷 1586-1591页

作者： Fahrettin Akay Mehmed ugur Isιk Berkay Akmaz Yusuf Ziya güven Department of Ophthalmology Izmir Katip Celebi University Atatürk Educating and Research HospitalIzmir 35620Turkey Department of Ophthalmology Kastamonu University Faculty of MedicineKastamonu 37100Turkey

AIM:To compare the efficacy of bevacizumab,ranibizumab,and aflibercept in pseudophakic cystoid macular edema(CME)patients with Irvine-gass syndrome(IgS).METHODS:This study is designed as retrospective consecutive case *** who developed postoperative pseudophakic CME that refractory to topical treatment and were treated with anti-vascular endothelial growth factor(VEgF)agents included in the *** coherence tomography(OCT)examination including central macular thickness(CMT),total macular volume(TMV),retinal nerve fiber layer(RNFL),ganglion cell layer(gCL)and choroidal thickness(ChT)measurements at the baseline,1 st,3 rd and 6 th month controls were ***:Fifty-nine eyes of 59 patients with CME and other healthy eyes of the patients(Control group)were *** were 22 eyes of 22 patients in the bevacizumab group(group 1),19 eyes of 19 patients in the ranibizumab group(group 2),and 18 eyes of 18 patients in the aflibercept group(group 3).There was no difference in terms of age,gender,axial length,IOP,and spherical equivalent *** baseline subfoveal and mean ChT were higher in the IgS *** difference between the baseline and sixth month values of subfoveal and mean ChT were compared in the CME groups,thinning was observed in all three *** was thinner in the patient group at the 6 th month of *** resolution time of CME was observed faster in group ***:All three anti-VEgF agents seem to be effective in CME but bevacizumab appears to be slightly more cost-effective than the other two alternatives.

关键词： anti-VEgF agents choroidal thickness ganglion cell complex Irvine-gass syndrome macular edema