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Chinese Physics B 2015年第11期24卷 478-482页

作者： m.a.hadi m.A.Alam m.Roknuzzaman m.T.Nasir A.K.m.A.Islam S.H.Naqib Department of Physics University of Rajshahi Department of Physics Rajshahi University of Engineering and Technology Department of Physics Jessore University of Science and Technology International Islamic University Chittagong

The structural, elastic, and electronic properties of the very recently discovered ternary silicide superconductor, Li2IrSi3, are calculated using an ab-initio technique. We adopt the plane-wave pseudopotential approach within the frame- work of the first-principles density functional theory （DFT） implemented by the CASTEP code. The calculated structural parameters show reasonable agreement with the experimental results. The elastic moduli of this interesting material are calculated for the first time. The electronic band structure and electronic energy density of states indicate the strong cova- lent Ir-Si and Si-Si bonding, which leads to the formation of the rigid structure of Li2IrSi3. Strong covalency gives rise to a high Debye temperature in this system. We discuss the theoretical results in detail in this paper.

关键词： silicide superconductor crystal structure elastic properties electronic structures

New ordered mAX phase mo_2 TiAlC_2: Elastic and electronic properties from first-principles

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Chinese Physics B 2016年第10期25卷 323-329页

作者： m.a.hadi m S Ali Department of Physics University of Rajshahi Department of Physics Pabna University of Science and Technology

First-principles computation on the basis of density functional theory(DFT) is executed with the CASTEP code to explore the structural, elastic, and electronic properties along with Debye temperature and theoretical Vickers’ hardness of newly discovered ordered mAX phase carbide mo2TiAlC2. The computed structural parameters are very reasonable compared with the experimental results. The mechanical stability is verified by using the computed elastic constants. The brittleness of the compound is indicated by both the Poisson’s and Pugh’s ratios. The new mAX phase is capable of resisting the pressure and tension and also has the clear directional bonding between atoms. The compound shows significant elastic anisotropy. The Debye temperature estimated from elastic moduli(B, G) is found to be 413.6 K. The electronic structure indicates that the bonding nature of mo2TiAlC2is a mixture of covalent and metallic with few ionic characters. The electron charge density map shows a strong directional mo–C–mo covalent bonding associated with a relatively weak Ti–C *** calculated Fermi surface is due to the low-dispersive mo 4d-like bands, which makes the compound a conductive *** hardness of the compound is also evaluated and a high value of 9.01 GPa is an indication of its strong covalent bonding.

关键词： new ordered mAX phase density functional theory calculations Debye temperature Vickers hardness

Control over hysteresis curves and thresholds of optical bistability in different semiconductor double quantum wells

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Chinese Physics B 2015年第8期24卷 373-380页

作者： Hamedi H R mehmannavaz m R Afshari hadi Institute of Theoretical Physics and Astronomy Vilnius University Young Researchers and Elite Club Mashhad Branch Islamic Azad University Research Institute for Applied Physics University of Tabriz

The effects of optical field on the phenomenon of optical bistability(OB) are investigated in a K-type semiconductor double quantum well(SDQW) under various parametric conditions. It is shown that the OB threshold can be manipulated by increasing the intensity of coupling field. The dependence of the shift of OB hysteresis curve on probe wavelength detuning is then explored. In order to demonstrate controllability of the OB in this SDQW, we compare the OB features of three different configurations which could arise in this SDQW scheme, i.e., K-type, Y-type, and inverted Y-type systems. The controllability of this semiconductor nanostructure medium makes the presented OB scheme more valuable for applications in all-optical switches, information storage, and logic circuits of all optical information processing.

关键词： optical bistability semiconductor double quantum wells K-type Y-type and inverted Y-type schemes OB threshold intensity

New ternary superconducting compound LaRu2As2： Physical properties from density functional theory calculations

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Chinese Physics B 2017年第3期26卷 453-460页

作者： m.a.hadi m S Ali S H Naqib A K m A Islam Department of Physics University of Rajshahi Rajshahi 6205 Bangladesh Department of Physics Pabna University of Science and Technology Pabna 6600 Bangladesh International Islamic University Chittagong Chittagong 4203 Bangladesh

In this paper, we perform the density functional theory （DFT） -based calculations by the first-principles pseudopo- tential method to investigate the physical properties of the newly discovered superconductor LaRu2As2 for the first time. The optimized structural parameters are in good agreement with the experimental results. The calculated independent elas- tic constants ensure the mechanical stability of the compound. The calculated Cauchy pressure, Pugh＇s ratio as well as Poisson＇s ratio indicate that LaRu2As2 should behave as a ductile material. Due to low Debye temperature, LaRu2As2 may be used as a thermal barrier coating （TBC） material. The new compound should exhibit metallic nature as its valence bands overlap considerably with the conduction bands. LaRu2As2 is expected to be a soft material and easily machinable because of its low hardness value of 6.8 GPa. The multi-band nature is observed in the calculated Fermi surface. A highly anisotropic combination of ionic, covalent and metallic interactions is expected to be in accordance with charge density calculation.

关键词： new superconductor LaRu2As2 density functional theory (DFT) calculations mechanical proper-ties electronic features

An adaptive finite element procedure for crack propagation analysis

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第2期8卷 228-236页

作者： ALSHOAIBI Abdulnaser m. hadi m.S.A. ARIFFIN A.K. Department of mechanical & materials Engineering Universiti Kebangsaan malaysia 43600 Bangi Selangor Darul Ehsan Malaysia

This paper presents the adaptive mesh finite element estimation method for analyzing 2D linear elastic fracture problems. The mesh is generated by the advancing front method and the norm stress error is taken as a posteriori error estimator for the h-type adaptive refinement. The stress intensity factors are estimated by a displacement extrapolation technique. The near crack tip displacements used are obtained from specific nodes of natural six-noded quarter-point elements which are generated around the crack tip defined by the user. The crack growth and its direction are determined by the calculated stress intensity factors. The maximum circumference theory is used for the latter. In evaluating the accuracy of the estimated stress intensity factors, four cases are tested consisting of compact tension specimen, three-point bending specimen, central cracked plate and double edge notched plate. These were carried out and compared to the results from other studies. The crack trajectories of these specimen tests are also illustrated.

关键词： Linear elastic fracture mechanics Adaptive refinement Stress intensity factors Crack propagation

Energy Efficient Scheduler of Aperiodic Jobs for Real-time Embedded Systems

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International Journal of Automation and computing 2020年第5期17卷 733-743页

作者： Hussein El Ghor El-hadi mAggoune University Institute of Technology Lebanese UniversityLebanon Sensor Networks and Cellular Systems(SNCS)Research Center UTSaudi Arabia Electrical Engineering Department University of Tabuk Sensor Networks and Cellular Systems(SNCS)Research Center 71491 TabukSaudi Arabia

Energy consumption has become a key metric for evaluating how good an embedded system is,alongside more performance metrics like respecting operation deadlines and speed of *** improvement is no longer the only metric by which optimality is *** fact,energy efficiency is becoming a preferred choice with a fundamental objective to optimize the system's *** this work,we propose an optimal energy efficient scheduling algorithm for aperiodic real-time jobs to reduce CPU energy ***,we apply the concept of real-time process scheduling to a dynamic voltage and frequency scaling(DVFS)*** address a variant of earliest deadline first(EDF)scheduling algorithm called energy saving-dynamic voltage and frequency scaling(ES-DVFS)algorithm that is suited to unpredictable future energy production and irregular job *** prove that ES-DVFS cannot attain a total value greater than C/ˆSα,whereˆS is the minimum speed of any job and C is the available energy *** also investigate the implications of having in advance,information about the largest job size and the minimum speed used for the competitive factor of *** show that such advance knowledge makes possible the design of semi-on-line algorithm,ES-DVFS∗∗,that achieved a constant competitive factor of 0.5 which is proved as an optimal competitive *** experimental study demonstrates that substantial energy savings and highest percentage of feasible job sets can be obtained through our solution that combines EDF and DVFS optimally under the given aperiodic jobs and energy models.

关键词： Real-time systems energy efficiency aperiodic jobs scheduling dynamic voltage scaling low-power systems embedded systems

Spectral features and antibacterial properties of Cu-doped ZnO nanoparticles prepared by sol-gel method

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Chinese Physics B 2016年第7期25卷 459-465页

作者： Alireza Samavati A F Ismail hadi Nur Z Othaman m K mustafa Centre for Sustainable Nanomaterials Ibnu Sina Institute for Scientific and Industrial ResearchUniversiti Teknologi Malaysia Advanced membrane Technology Research Centre (AmTEC) Universiti Teknologi Malaysia Faculty of Science Technology and Human Development Universiti Tun Hussein Onn Malaysia

Zn（1-x）Cux O（x=0.00, 0.01, 0.03, and 0.05） nanoparticles are synthesized via the sol-gel technique using gelatin and nitrate precursors. The impact of copper concentration on the structural, optical, and antibacterial properties of these nanoparticles is demonstrated. Powder x-ray diffraction investigations have illustrated the organized Cu doping into ZnO nanoparticles up to Cu concentration of 5%（x = 0.05）. However, the peak corresponding to CuO for x= 0.01 is not distinguishable. The images of field emission scanning electron microscopy demonstrate the existence of a nearly spherical shape with a size in the range of 30–52 nm. Doping Cu creates the Cu–O–Zn on the surface and results in a decrease in the crystallite size. Photoluminescence and absorption spectra display that doping Cu causes an increment in the energy band gap. The antibacterial activities of the nanoparticles are examined against Escherichia coli（Gram negative bacteria）cultures using optical density at 600 nm and a comparison of the size of inhibition zone diameter. It is found that both pure and doped ZnO nanoparticles indicate appropriate antibacterial activity which rises with Cu doping.

关键词： Cu-doped ZnO nanoparticles photoluminescence antibacterial E.coli

Evaluation of electrical and optical characteristics of ZnO/CdS/CIS thin film solar cell

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Chinese Physics B 2016年第2期25卷 388-392页

作者： hadi Zarei Rasoul malekfar Department of Physics Tarbiat Modares University P O. Box 14115-175 Tehran I. R./ran

In this study, device modeling and simulation are conducted to explain the effects of each layer thickness and temperature on the performance of ZnO/CdS/CIS thin film solar cells. Also, the thicknesses of the CIS and CdS absorber layers are considered in this work theoretically and experimentally. The calculations of solar cell performances are based on the solutions of the well-known three coupling equations： the continuity equation for holes and electrons and the Poisson equation. Our simulated results show that the efficiency increases by reducing the CdS thickness. Increasing the CIS thickness can increase the efficiency but it needs more materials. The efficiency is more than 19% for a CIS layer with a thickness of 2 μm. CIS nanoparticles are prepared via the polyol route and purified through centrifugation and precipitation *** nanoparticles are dispersed to obtain stable inks that could be directly used for thin-film deposition via spin *** also obtain x-ray diffraction（XRD） peak intensities and absorption spectra for CIS experimentally. Finally, absorption spectra for the CdS window layer in several deposition times are investigated experimentally.

关键词： CIGS solar cell thin film efficiency CdS XRD

Applying the Protective mn-Co-La_(2)O_(3)Coating on Crofer 22 APU Ferritic Stainless Steel Used as Solid Oxide Fuel Cell Interconnects

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Acta metallurgica Sinica(English Letters) 2024年第5期37卷 872-888页

作者： Farhad mohsenifar hadi Ebrahimifar Ahmad Irannejad Department of materials Engineering and metallurgy Faculty of EngineeringShahid Bahonar University of KermanKermanIran mechanical Engineering Department Faculty of EngineeringHigher Education Complex of Bam76615-314BamIran Department of materials Engineering Faculty of Mechanical and Materials EngineeringGraduate University of Advanced TechnologyKerman ***Iran

This research studies the effect of mn-Co-La_(2)O_(3) coating synthesized by the electrodeposition method on the oxidation resistance and electrical conductivity of the Crofer 22 APU stainless steel interconnect plates in solid oxide fuel *** test samples were characterized by a field emission scanning electron microscope(FESEm)equipped with energy dispersive spectroscopy(EDS),X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS).The oxidation kinetics of the coated and uncoated samples were studied by tracking their weight changes over time at 800°C,showing that the oxidation mechanism for all samples follows the parabolic *** oxidation rate constant(k_(p))values of the coated sample compared with that of the uncoated one indicated a reduction in the oxidation rate of the steel substrate in the presence of the mn-Co-La_(2)O_(3) *** examination of the cross-section of different samples after the isothermal oxidation for 500 h at 800°C exhibited that applying the composite coating leads to a decrease in the thickness of the chromia layer formed on the steel ***,under these conditions,the area-specific resistance(ASR)of the coated sample(13.11 mΩcm^(2))is significantly lower than that of the uncoated one(41.45 mΩcm^(2)).

关键词： Area specific resistance Oxidation Fuel cell Composite coating

Tensile and tear-type fracture toughness of gypsum material:Direct and indirect testing methods

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Journal of Rock mechanics and Geotechnical Engineering 2023年第7期15卷 1777-1796页

作者： Daniel Pietras m.R.m.Aliha hadi G.Kucheki Tomasz Sadowski Lublin University of Technology Civil Engineering and architecture departmentNadbystrzycka 40 str20-618LublinPoland Welding and Joining Research Center School of Industrial EngineeringIran University of Science and Technology(IUST)Narmak16846-13114TehranIran

In this context,four specimens,i.e.(i)circumferentially notched cylindrical torsion(CNCT),(ii)circum-ferentially notched cylindrical direct tension(CNCDT),(iii)edge notch disc bend(ENDB)and(iv)three-point bend beam(3PBB),were utilized to measure the modesⅠandⅢfracture toughness values of *** the CNCT specimen provides pure modeⅢloading in a direct manner,this pure mode condition is indirectly produced by the ENDB *** ENDB specimen provided lower KⅢc and a non-coplanar(***)fracture surface compared with the CNCT specimen,which showed a planar modeⅢfracture *** ENDB specimen is also employed for conducting pure modeⅠ(with different crack depths)and mixed modeⅠ/Ⅲ*** value was independent of the notch depth,and it was consistent with the RILEm and ASTm standard *** the modeⅢfracture results were highly sensitive to the notch *** the fracture resistance against modeⅢwas significantly lower than that of modeⅠ,the greater work of fracture under modeⅢwas noticeable.

关键词： Gypsum Pure modesⅠandⅢfracture toughness mixed modeⅠ/Ⅲ Circumferentially notched cylindrical torsion(CNCT)specimen Circumferentially notched cylindrical direct tension(CNCDT)specimen Edge notch disc bend(ENDB)specimen Experimental measurement Geometry and loading type effects