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microstructure Dependent Fatigue Cracking Resistance of Ti-6.5Al-3.5mo-1.5Zr-0.3Si Alloy

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Journal of materials Science & Technology 2012年第7期28卷 614-621页

作者： Z.m. Song l.m. lei b. Zhang X. Huang G.R Zhang Shenyang National laboratory for materials Science Institute of Metal Research Chinese Academy of SciencesShenyang 110016 China AVIC Commercial Aircraft Engine Co. Ltd. Shanghai 200241 China Titanium Alloys laboratory Beijing Institute of Aeronautical Materials Beijing 100095 China Key laboratory for Anisotropy and Texture of materials of ministry of Education School of Materials and MetallurgyNortheastern University Shenyang 110819 China

Fatigue cracking behavior from a notch was investigated at room temperature for ***-3.5mo-1.5Zr- 0.3Si （TClI） alloys with four different microstructures obtained at different cooling rates from the β transus temperature. It was found that the alloy with l.m.llar structures consisting of α/β l.m.llae or acicular α＇ martensite laths had a higher fatigue crack initiation threshold from the notch, while the bimodal structure with coarse a grain had a lower fatigue cracking resistance. The alloy with α/β l.m.llar structure showed a higher fatigue crack growth resistance. The length scales of the microstructures were characterized to correlate with fatigue cracking behavior. Fatigue cracking mechanism related to microstructures was discussed.

关键词： Ti alloy Fatigue crack initiation Crack propagation microstructure

Influence of Solid Fraction on Gravity Segregation of Sn in A1-20Sn Alloy Casting

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Journal of materials Science & Technology 2000年第6期16卷 577-580页

作者： Zhang, P. Du, Y.H. Zeng, D.b. Cui, J.Z. ba, l.m. Dep. of mechanical Eng. Tsinghua Univ. Beijing 100084 China

The influence of solid fraction of Al-20Sn alloy mushy on gravity segregation of Sn in casting was studied . The relationship between solid fraction and the temperature of alloy mushy and that between solid fraction of alloy mushy and size of Sn particle in ingot were determined. The results show that the relationship between solid fraction and the temperature of alloy mushy was fb>sb>=1683-4.86t+0.003 5t2. The extent of gravity segregation of Sn in casting reduced gradually with the increase of solid fraction of alloy mushy. When solid fraction of alloy mushy was larger than 40%, the gravity segregation of Sn in casting could be removed basically, and the relationship between solid fraction of alloy mushy and size of Sn particle in ingot was s=-0.64fb>sb>+70.8.

关键词： metal casting

Effect of periodic heat transfer on the transient thermal behavior of a convective-radiative fully wet porous moving trapezoidal fin

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Applied mathematics and mechanics(English Edition) 2023年第4期44卷 653-668页

作者： b.J.GIREESHA m.l.KEERTHI Department of PG Studies and Research in mathematics Kuvempu UniversityShankaraghatta 577451India

A moving trapezoidal profiled convective-radiative porous longitudinal fin wetted in a single-phase fluid is considered in the current *** periodic variation in the fin base temperature is taken into account along with the temperature sensitive thermal conductivity and convective heat transfer *** modeled probl.m.which is resolved into a non-linear partial differential equation(PDE),is made dimensionless and solved by employing the finite difference method(FDm).The results are displayed through graphs and *** effects of amplitude,frequency of oscillation,wet nature,Peclet number,and other relevant quantities on the distribution of temperature through the fin length and with the dimensionless time are *** is deciphered that the periodic heat transfer gives rise to the wavy nature of the fin thermal profile against *** analysis is beneficial in the design of fin structures for applications like solar collectors,space/airborne applications,and refrigeration industries.

关键词： convection fully wet porous fin trapezoidal profile moving fin unsteady periodic thermal condition

A theoretical investigation of the band alignment of type-I direct band gap dilute nitride phosphide alloy of GaN_xAs_yP_(1-x-y)/GaP quantum wells on GaP substrates

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Chinese Physics b 2014年第7期23卷 640-644页

作者： O l nsal b Gnül.m.Temiz Department of Engineering Physics University of Gaziantep

The GaP-based dilute nitride direct band gap material Ga（NAsP） is gaining importance due to the monolithic integra- tion of laser diodes on Si microprocessors. The major advantage of this newly proposed laser material system is the small lattice mismatch between GaP and Si. However, the large threshold current density of these promising laser diodes on Si substrates shows that the carrier leakage plays an important role in Ga（NAsP）/GaP QW lasers. Therefore, it is necessary to investigate the band alignment in this laser material system. In this paper, we present a theoretical investigation to optimize the band alignment of type-I direct band gap GaNxAsyP1-x-y/GaP QWs on GaP substrates. We examine the effect of nitrogen （N） concentration on the band offset ratios and band offset energies. We also provide a comparison of the band alignment of type-I direct band gap GaNxAsyP1-x-y/GaP QWs with that of the GaNxAsyP1-x-y/Al2Ga1-2P QWs on GaP substrates. Our theoretical calculations indicate that the incorporations of N into the well and AI into the barrier improve the band alignment compared to that of the GaAsP/GaP QW laser heterostructures.

关键词： quantum well band alignment carrier confinement dilute nitride phosphide alloy

A Search on Dirac Equation

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Chinese Physics letters 2007年第11期24卷 3024-3027页

作者： m. Kocak, b. Gonül Department of Engineering Physics Faculty of Engineering University of Gaziantep 27310 Gaziantep Turkey

The solutions, in terms of orthogonal polynomials, of Dirac equation with analytically solvable potentials are investigated within a novel formalism by transforming the relativistic equation into a Schrodinger-like one. Earlier results are discussed in a unified framework, and some solutions of a large class of potentials are given.

关键词： coated conductor buffer layer self-epitaxy CeO2

Remarks on Exact Solvability of Quantum Systems with Spatially Varying Effective mass

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Chinese Physics letters 2005年第11期22卷 2742-2745页

作者： b. Goenül.m. Kocak Department of Engineering Physics Faculty of Engineering University of Gaziantep 27310 Gaziantep Türkiye

Within the frame of a novel treatment we make a complete mathematical analysis of exactly solvable onedimensional quantum systems with non-constant mass, involving their ordering ambiguities. This work extends the results recently reported in the literature and clarifies the relation between physically acceptable effective mass Hamiltonians.

关键词： DEPENDENT EFFECTIVE mASSES SUPERSYmmETRIC APPROACH SCHRODINGER-EQUATION PERTURbATION-THEORY POTENTIAlS SEmICONDUCTORS STATES

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–Col.m.n 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

Unsteady generalized Couette flow in composite microchannel

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Applied mathematics and mechanics(English Edition) 2011年第1期32卷 23-32页

作者： m.l.KAURANGINI b.K.JHA Department of mathematical Sciences Kano University of Science and Technology Department of mathematics Ahmadu Bello University

A numerical study is reported on the fully developed unsteady l.m.nar fluid flow in microchannel parallel-plates partially filled with a uniform porous medium and partially filled with a clear fluid. The flow is induced by the movement of one of the plates and the pressure gradient. The brinkman-extended Darcy model is utilized to model the flow in the porous region, while the Stokes equation is used in the clear fluid region. A theoretical analysis is also presented for the fully developed steady flow to find closed- form expressions for the interracial velocity and the velocity and skin frictions at the bounding plates. Numerical computations shows excellent agreement between the closedform solutions for fully developed steady flow and the numerical solution to unsteady flow at large values of time.

关键词： unsteady flow composite microchannel

Effects of stretching/shrinking on the thermal performance of a fully wetted convective-radiative longitudinal fin of exponential profile

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Applied mathematics and mechanics(English Edition) 2022年第3期43卷 389-402页

作者： b.J.GIREESHA m.l.KEERTHI G.SOWmYA Department of PG Studies and Research in mathematics Kuvempu UniversityShankaraghatta 577451India Department of PG mathematics The National College(Auto)Bangalore 560070India

The present investigation focuses on the thermal performance of a fully wet stretching/shrinking longitudinal fin of exponential profile coated with a mechanism like a conveyer *** modeled equation is non-dimensionalized and solved by applying the Runge-Kutta-Fehlberg(RKF)*** effects of parameters such as the wet parameter,the fin shape parameter,and the stretching/shrinking parameter on the heat transfer and thermal characteristics of the fin are graphically analyzed and *** is inferred that the negative effects of motion and internal heat generation on the fin heat transfer rate can be lessened by setting a shrinking mechanism on the fin *** current examination is inclined towards practical applications and is beneficial to the design of fins.

关键词： fully wet longitudinal fin convection exponential profile internal heat generation moving fin