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bandgap engineering to tune the optical properties of be_xmg_(1-x)X(X=S, Se, Te) alloys

Chinese Physics b 2018年第1期27卷 415-423页

作者： b Sabir N A Noor m Rashid Fasih Ud Din Shahid m Ramay Asif mahmood Centre for Advanced Studies in Physics Government College University Department of Physics School of Science University of Management and TechnologyLahore Pakistan Department of Physics COMSATS Institute of Information Technology Physics and Astronomy Department College of Science King Saud University Chemical Engineering Department College of Engineering King Saud University

Structural, electronic, and optical properties of alloys bexmgl-xX （X = S, Se, Te） in the assortment 0 〈 x 〈 1 were theoretically reported for the first time in zinc-blende （Zb） phase. The calculations were carried out by using full-potential linearized augmented plane wave plus local orbitals （FP-LAPW＋lo） formalism contained by the framework of density functional theory （DFT）. Wu--Cohen （WC） generalized gradient approximation （GGA）, based on optimization energy, has been applied to calculate these theoretical results. In addition, we used becke and Johnson （mbJ-GGA） potential, modified form of GGA functional, to calculate electronic structural properties up to a high precision degree. The alloys were composed with the concentrations x = 0.25, 0.5, and 0.75 in pursuance of ＇special quasi-random structures＇（SQS） approach of Zunger for the restoration of disorder around the observed site of alloys in the first few shells. The structural parameters have been predicted by minimizing the total energy in correspondence of unit cell volume. Our alloys established direct band gap at different concentrations that make their importance in optically active materials. Furthermore, density of states was discussed in terms of the contribution of be and mg s and chalcogen （S, Se, and Te） s and p states and observed charge density helped us to investigate the bonding nature. by taking into consideration of immense importance in optoelectronics of these materials, the complex dielectric function was calculated for incident photon energy in the range 0--15 eV.

关键词： bexmgl-xX (X = S Se Te) alloys zinc-blende (Zb) phase density functional theory (DFT),electronic and optical properties

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Dissolution mechanism of a Zr Rich Structure in a Ni_3Al base Alloy

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Journal of materials Science & Technology 2011年第10期27卷 885-892页

作者： H.b.motejadded m.Soltanieh S.Rastegari School of materials Science and Engineering Iran University of Science and Technology

In the present research, the dissolution mechanism of a Zr rich structure during annealing of a Ni3Al base alloy containing Cr, mo, Zr and b, was investigated. The annealing treatments were performed up to 50 h at 900, 1000 and 1100℃. The alloy used in this investigation was produced by vacuum-arc remelting technique. The results show that at the beginning of the process, a mixed interface reaction and local equilibrium （long range diffusion） mechanism controls the dissolution process. After a short time, this mechanism changes and the dissolution mechanism of the Zr rich structure changes to only long range diffusion of Zr element. According to this mechanism, the activation energy of this process is estimated to be about 143.3 ***-1. Also the phases that contribute to this structure and the transformations that occur at the final steps of solidification of this alloy were introduced. According to the results, at the final step of solidification, a peritectic type reaction occurs in the form of L＋ y→Ni7Zr2 and →-Ni7Zr2 segregates from the melt. Following this transformation, →-Ni7Zr2 eutectic separates from the remaining Zr rich liquid. The solidification process will be terminated by a ternary eutectic reaction in the form of L→y＋Ni5Zr＋Ni7Zr2.

关键词： Ni3Al base alloy microstructure Dissolution kinetics Activation energy

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Symmetry in optics and photonics:a group theory approach

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Science bulletin 2018年第4期63卷 244-251页

作者： b.m.Rodriguez-Lara Ramy EI-Ganainy Julio Guerrero Tecnologico de monterrey.Escuela de Ingenieria y Ciencias Monterrey 64849Mexico Instituto Nacional de Astrofisica Optica y Electr6nicaPueblaCP 72840Mexico Department of Physics and Hexes Center for Quantum Phenomena Michigan Technological UniversityHoughton.MI 49931USA Departamento de matematicas Facultad de Ciendas Experimentales y de la SaludCampus Las LagunillasUniversidad de Jaen23071JaenSpain Departamento de Ingenierfa y Tecnologia de Computadores Facultad de lnformdticaCampus EspinardoUnivesidad de Murcia30100 MurciaSpain

Group theory(GT) provides a rigorous framework for studying symmetries in various disciplines in physics ranging from quantum field theories and the standard model to fluid mechanics and chaos theory. To date, the application of such a powerful tool in optical physics remains limited. Over the past few years however, several quantum-inspired symmetry principles(such as parity-time invariance and supersymmetry) have been introduced in optics and photonics for the first time. Despite the intense activities in these new research directions, only few works utilized the power of group theory. motivated by this status quo, here we present a brief overview of the application of GT in optics, deliberately choosing examples that illustrate the power of this tool in both continuous and discrete setups. We hope that this review will stimulate further research that exploits the full potential of GT for investigating various symmetry paradigms in optics, eventually leading to new photonic devices.

关键词： Group theoryHelmholtz equationDiscrete opticsParity-time (PT) symmetry

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ON PERTURbED AbSTRACT FUNCTIONAL INTEGRODIFFERENTIAL EQUATION

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Acta mathematica Scientia 1988年第3期8卷 263-282页

作者： m.b.Dhakne,b.G.Pachpatte Dept.of math.& Stat. marathwada Univ. Aurangabad India Dept.of math.& Stat. marathwada Univ. Aurangabad India

In the present paper the existence of a unique strong solution of a general nonlinear perturbed abstract functional integ odifferential equation is investigated. The technique used in the proof of our main r esult is based on Kato's approach recently extended by Kartsatos and Parrott to evolution equations involving functional perturbations.

关键词： lim Holder 一夕

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Numerical analysis for peristaltic transport of Carreau-Yasuda fluid with variable thermal conductivity and convective conditions

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Journal of Central South University 2015年第11期22卷 4467-4475页

作者： F.m.Abbasi T.Hayat b.Ahmad Department of mathematics Comsats Institute of Information Technology Department of mathematics Quaid-I-Azam University 45320 Nonlinear Analysis and Applied mathematics (NAAm) Research Group Faculty of Science King Abdulaziz University

Peristalsis of Carreau-Yasuda fluid is investigated. Analysis is carried out in the presence of velocity slip and convective boundary conditions. Thermal conductivity of the fluid is taken to be temperature dependent. Lubrication analysis is used in the formulation of the problem. Resulting nonlinear system of equations is solved numerically. Impact of embedded parameters on the quantities of interest is examined through graphs and tables. Comparison of the behavior of the Carreau-Yasuda, Carreau and Newtonian fluid models is presented. Results show that the heat transfer rate at the wall for the Carreau fluid model is large when compared with the Newtonian or the Carreau-Yasuda fluid model. Also the heat transfer rate at the wall decreases with increase in the velocity slip and variable thermal conductivity parameters. Further, an increase in the biot number reduces the fluid temperature by a considerable amount.

关键词： peristaltic transport Carreau-Yasuda fluid variabl

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Coarsening Kinetics of γ' Precipitates in Dendritic Regions of a Ni_3 Al base Alloy

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Journal of materials Science & Technology 2012年第3期28卷 221-228页

作者： H.b.motejadded m.Soltanieh S.Rastegari School of metallurgy and materials Engineering Iran University of Science and TechnologyTehranIran

Coarsening behavior of γ＇ precipitates in the dendritic regions of a Ni 3 Al base alloy containing chromium,molybdenum,zirconium and boron was *** treatment was performed up to 50 h at 900,1000 and 1100℃.The alloy was produced by vacuum-arc remelting *** show that coarsening of the γ＇ precipitates in this complex alloy containing high volume fractions of γ＇ phase follows Lifshitz-Slyozov-Wagner（LSW） *** activation energy of the γ＇ precipitates was evaluated to be about 253.5 ***-1 which shows that the growth phenomenon is controlled by volume diffusion of *** an innovative approach,diffusion coefficient of the solute element（s） and the interfacial energy between γ＇ precipitates and γ＇（matrix） were estimated at 900,1000 and 1100℃.Accordingly,the interfacial energies at 900,1000 and 1100℃ are 4.49±1.48,2.08±0.69 and 0.98±0.32 mJ.m-2,*** the diffusivities of solute element（s） at these temperatures are 3.41±1.08,30±9.5 and 145.15±45.85（10-15 m-2.s-1）,respectively.

关键词： Ni3 Al base intermetallic Coarsening kinetics Activation energy

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Effects of nano-voids and nano-cracks on the elastic properties of a host medium: xfem modeling with level-set function and free surface energy

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Acta mechanica Sinica 2019年第4期35卷 799-811页

作者： b.E. Hachi D. Hachi m. Haboussi Laboratoire de Développement en mécanique et matériaux (LDmm) Université de Djelfa PB 3117 Djelfa Algérie Laboratoire d’Automatique Appliquée et Diagnostics Industriels (LAADI) Université de Djelfa PB 3117 Djelfa Algérie Laboratoire des Sciences des Procédés et des matériaux (LSPm) Université Paris 13 UPR 3407 CNRS Paris France

This work deals with the influences of nano-heterogeneities in the form of voids/cavities or cracks on the elastic (please confirm which word is correct. effective or elastic? According to the title of paper, I choose elastic.) properties of a host medium. With a relatively large ratio of apparent-surface to volume and particularly strong physical interactions with the surrounding medium at nano-scale, nano-heterogeneities can potentially affect the elastic(effective or elastic?) properties of the parent medium (matrix) containing them in a significant manner. This has been reported by various theoretical and experimental studies, some of them are discussed in the present paper. To describe the positive (reinforcement) or negative (degradation) effect of the nano-heterogeneities from the modeling perspective, it is necessary to take into account the energy of interfaces/surfaces between nano-heterogeneities and the matrix which, by the fact of the relatively large extent of their apparent surface and their strong physical interaction with their neighborhood, can no longer be neglected compared to those of the volume energy. Thus, to account for the effects of interfaces/surfaces in a nanostructured heterogeneous medium, the coherent interface model is considered in the present investigation within a periodic homogenization procedure. In this interface/surface model, the displacement vector is assumed to be continuous across the interface while the stress vector is considered to be discontinuous and satisfying the Laplace-Young equations. To solve these equations coupled to the classical mechanical equilibrium problem, a numerical simulation tool is developed in a two-dimensional (2D) context using the eXtended Finite Element method (XFEm) and the Level-Set functions. The developed numerical tool is then used to carry out a detailed analysis about the effect of nano-heterogeneities on the overall mechanical properties of a medium. The nano-heterogeneities are present

关键词： Interface/Surface energy XFEm Level-Set function Periodic homogenization Nano-voids/Nano-cavities Nano-cracks Nano-inclusions/Nano-heterogeneities

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Influence of the Thermal barrier Coatings Design on the Oxidation behavior

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Journal of materials Science & Technology 2009年第4期25卷 499-507页

作者： b. Saeedi A. Sabour A. Ebadi A.m. Khoddami materials Engineering Department at Tarbiat modares University materials Engineering Faculty Tehran University

The properties of two different types of thermal barrier coatings （TbCs） were compared to improve the surface characteristics on high temperature components. These TbCs consisted of a duplex TbC and a five-layered functionally graded TbC. NiCrAIY bond coats were deposited on a number of Inconel-738LC specimens using high velocity oxy-fuel spraying （HVOF） technique. For duplex coating, a group of these specimens were coated with yttria stabilized zirconia （YSZ） using plasma spray technique. Functionally graded NiCrAIY/YSZ coatings were fabricated by plasma spray using co-injection of the two different powders in a single plasma torch. The amount of zirconia in functionally graded coatings were gradually increased from 30 to 100 vol. pct. microstructural changes, thermally grown oxide （TGO） layer growth and damage initiation of the coatings were investigated as a function of isothermal oxidation test at 970℃. As a complementary test, the performance of the fabricated coatings by the optimum processing conditions was evaluated as a function of intense thermal cycling test at 1100℃. Also the strength of the adhesive coatings of the substrate was also measured. microstructural characterization was analyzed by scanning electron microscopy （SEm） and optical microscopy whereas phase analysis and chemical composition changes of the coatings and oxides formed during the tests were studied by XRD （X-ray diffraction） and EDS （energy dispersive spectrometer）. The results showed that microstructure and compositions gradually varied in the functionally graded coatings. by comparison of duplex and functionally graded TbCs oxidation behavior （duplex failure after 1700 h and funcitionally graded TECs failure after 2000 h）, thermal shock test and adhesion strength of the coatings, the functionally graded TbC had better performance and more durability.

关键词： Thermal barrier coatings (TbCs) Isothermal oxidation Functionally graded TbC Thermally grown oxide bond strength High velocity oxy-fuel spraying

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Synthesis, spectroscopic characterization, and thermal decomposition kinetics of some lanthanide(III) nitrate complexes of 2-(N-o-hydroxyacetophenone) amino-3-carboxyethyl-4,5,6,7-tetrahydrobenzo[b]thiophene

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Journal of Rare Earths 2008年第4期26卷 463-468页

作者： K. mohanan m. Thankamony b. Sindhu Kumari Department of Chemistry University of Kerala Kariavattom Campus Trivandrum-695 581. Kerala India

Complexes of La（Ⅲ）, Ce（Ⅲ）, Pr（Ⅲ）, Nd（Ⅲ）, Sm（Ⅲ）, Eu（Ⅲ）, Gd（Ⅲ）, Dy（Ⅲ）, Yb（Ⅲ）, and Lu0ID with 2-（N-o- hydroxyacetophenone）amino-3-carboxyethyl-4,5,6,7-tetrahydrobenzo[b]thiophene （HAAT） formed by the condensation of o-hydroxyacetophenone and 2-amino-3-carboxyethyl-4,5,6,7-tetrahydrobenzo[b]thiophene were synthesized and characterized on the basis of elemental analyses, molar conductance measurements, magnetic susceptibility data, UV-Visible, IR, and NmR spectral studies. The spectral data revealed that the ligand acted as a neutral tridentate coordinating to the metal ion through ONO donor sequence. A coordination number nine was proposed for the complexes. Thermal decomposition studies of the ligand and lanthanum（Ⅲ） complex were carried out and kinetic parameters were calculated using Coats-Redfem equation. The decomposition reactions followed random nucleation mechanism with one nucleus on each particle.

关键词： lanthanides o-hydroxyacetophenone molar conductance magnetic susceptibility thermal study rare earths

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Yield Traits and Associated marker Segregation in Elite Introgression Lines Derived from O. sativa × O. nivara

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Rice science 2018年第1期25卷 19-31页

作者： G.HARITHA b.P.m.SWAmY m.L.NAIK b.JYOTHI b.DIVYA S.mALATHI N.SARLA Indian Council of Agricultural Research Indian Institute of Rice Research Plant breeding Genetics and Biotechnology Division International Rice Research Institute

Introgression lines(ILs)derived from interspecific crosses are a source of new genetic variability.A total of 55 ILs derived from two crosses Swarna×*** IRGC81848(population A)and Swarna×*** IRGC81832(population b)were characterized for yield and yield-related traits/*** of 103 simple sequence repeat(SSR)markers associated with yield-related QTLs was *** A showed an average of 12.6%homozygous *** alleles and population b showed 10.6%.Interestingly,three SSR markers,Rm223,Rm128 and Rm517,showed conspicuous pattern of *** distribution of parental alleles at three loci Rm223,Rm128 and Rm517 linked to yield-related traits was *** markers flanked to several yield-related ***223,flanking to qyld8.3,was heterozygous in almost all the 55 ILs except in IL10-3S and ***128 on chromosome 1 and Rm517 on chromosome 3 were mutually exclusive in 46 out of 55 *** 46 ILs showed either of the marker allele Rm128 or Rm517 from *** but not ***166S had both Rm128and Rm517 from *** and the other ILs showed homozygous Swarna allele at Rm517 except *** structure assigned the 55 ILs to three sub-populations based on their genomic ***65S,IL166S,IL248S,IL7K and IL250K showed high yields in multi-location trials,and IL248S was released for cultivation as DRRDhan 40.

关键词： introgression line heterozygosity Oryza nivara wild rice population structure yield simple sequence repeat

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