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Journal of Natural Gas Chemistry 2009年第2期18卷 187-190页

作者： syed Tajammul Hussain Muhammad Mazhar Muhammad Arif Nadeem National Centre for Physics Quaid-i-Azam UniversityIslamabad 43520 Pakistan Department of Chemistry Quaid-i-Azam UniversityIslamabad 43520 Pakistan

In Fischer-Tropsch synthesis reaction, methane formation is one of the side reactions which must be suppressed in order to get better catalytic selectivity for light olefins. In the present study, we have modified cobalt based Fischer-Tropsch catalyst and developed a process to minimize methane production, consequently to produce maximum yield of light olefins. Manganese-cobalt oxide supported on H-5A zeolite catalyst was synthesized using modified H-5A zeolite, to increase its surface acid sites. Increased acidity of zeolite plays a major part in the suppression of methane formation during the Fischer-Tropsch reaction. The modified zeolite results in the electronic modification of catalyst surface by creating new active catalytic sites. The results are compared with other supported catalysts along with unmodified zeolite. Appreciable reduction in methane formation is achieved on modified zeolite supported catalyst in comparison with unsupported catalyst.

关键词： methane formation Fisher-Tropsch synthesis manganese cobalt suppression

Fractional Processing Based Adaptive Beamforming Algorithm

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Computers, Materials & Continua 2023年第7期76卷 1065-1084页

作者： syed Asghar Ali Shah Tariqullah Jan syed Muslim Shah Ruhul Amin Khalil Ahmad Sawalmeh Muhammad Anan Department of Electrical Engineering University of Engineering and TechnologyPeshawar25120Pakistan Department of Electrical Engineering Capital University of Science and TechnologyIslamabad44000Pakistan Department of Computer Science Northern Border UniversityArar91431Saudi Arabia Department of Software Engineering Alfaisal UniversityRiyadh11533Saudi Arabia

Fractional order algorithms have shown promising results in various signal processing applications due to their ability to improve performance without significantly increasing *** goal of this work is to inves-tigate the use of fractional order algorithm in the field of adaptive beam-forming,with a focus on improving performance while keeping complexity *** effectiveness of the algorithm will be studied and evaluated in this *** this paper,a fractional order least mean square(FLMS)algorithm is proposed for adaptive beamforming in wireless applications for effective utilization of *** algorithm aims to improve upon existing beam-forming algorithms,which are inefficient in performance,by offering faster convergence,better accuracy,and comparable computational *** FLMS algorithm uses fractional order gradient in addition to the standard ordered gradient in weight *** derivation of the algorithm is provided and supported by mathematical convergence *** is evaluated through simulations using mean square error(MSE)minimization as a metric and compared with the standard LMS algorithm for various *** results,obtained through Matlab simulations,show that the FLMS algorithm outperforms the standard LMS in terms of convergence speed,beampattern accuracy and scatter *** outperforms LMS in terms of convergence speed by 34%.From this,it can be concluded that FLMS is a better candidate for adaptive beamforming and other signal processing applications.

关键词： Adaptive beamforming adaptive array fractional processing least mean square fractional least mean square

Debating the magnesium-selenium battery technology

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Journal of Magnesium and Alloys 2020年第4期8卷 980-988页

作者： Muhammad Rashada syed Danish Ali Zaidi Muhammad Asif School of Materials Science and Engineering Jiangsu University of Science and TechnologyZhenjiang 212003JiangsuChina Advanced Rechargeable Batteries Laboratory Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China Department of Chemical Sciences School of Natural SciencesUniversity of LimerickLimerick V94 T9PXIreland

Magnesium ion batteries(MIBs)have received tremendous research attention owing to their low cost,dendrite free electroplating,and high theoretical capacities compared with lithium ion batteries(LIBs).Despite these advantages,the launching of MIBs is hindered by sluggish kinetics of the magnesium ions inside the host ***,several magnesium-selenium batteries have been developed to achieve the fast kinetics of magnesium ions inside the selenium-based ***,we have critically reviewed the five-year advancements made in the field of selenium cathode design,selenium loadings,compatible organic and inorganic electrolytes,their resultant reversible capacities,working voltages,cycle life,and specific *** selenium-based cathodes were critically debated in terms of their electrochemical performance and *** the end of this review article,several irmovative directions are proposed to shed light on future research.c 2020 Published by Elsevier *** behalf of Chongqing University.

关键词： Magnesium-selenium batteries Energy storage Selenium cathodes Electrolytes Electrochemical properties

Poincaré-MacMillan Equations of Motion for a Nonlinear Nonholonomic Dynamical System

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Chinese Physics Letters 2012年第3期29卷 132-134页

作者： Amjad Hussain syed Tauseef Mohyud-Din Ahmet Yildirim Department of Mathematics Zhejiang UniversityHangzhou 310027 Department of Mathematics HITEC UniversityTaxila Cantt Pakistan Department of Mathematics Ege University35100 Bornova IzmirTurkey University of South Florida Department of Mathematics and StatisticsTampaFL 33620-5700USA

MacMillan's equations are extended to Poincaré's formalism,and MacMillan's equations for nonlinear nonholonomic systems are obtained in terms of Poincaré*** equivalence of the results obtained here with other forms ... 详细信息

关键词： Poincaré parameters MacMillan

Fractional-calculus analysis of human immunodeficiency virus and CD4+T-cells with control interventions

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Communications in Theoretical Physics 2022年第10期74卷 1-15页

作者： Rashid Jan Salah Boulaaras syed Azhar Ali Shah Department of Mathematics University of SwabiSwabi 23430KPKPakistan Department of Mathematics College of Sciences and ArtsArRassQassim UniversitySaudi Arabia

It is undeniable that HIV infection has been a censorious public health concern over the past four *** is reported that HIV is the main reason for AIDs which has decimated the global population of humans and imposed a significant economic burden on affected ***,it is significant to study the transmission of HIV viruses in the body of a human *** this study,we use a fractional framework to organise the intricate interactions of CD4^(+)T-cells and HIV viruses in order to investigate HIV infection with control *** apply the operators of Caputo and Atangana–Baleanu to interrogate the transmission phenomena of HIV *** the analysis of our system,we present the basic concepts of the fractional *** schemes are provided to show the solution pathways of the system with the variation of input ***,the findings emphasise the chaotic and dynamical behaviour of *** run several simulations to visualise the influence of input factors and quantitatively illustrated the dynamics of *** and oscillatory behaviour are intimately linked,and this is owing to the system’s ***,our findings indicate the most important factors for infection control and prevention.

关键词： fractional-calculus HIV infection dynamics of HIV numerical method time series analysis

Buckling of thin-walled beams by a refined theory

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2012年第10期13卷 747-759页

作者： syed Muhammad IBRAHIM Erasmo CARRERA Marco PETROLO Enrico ZAPPINO Specialty Units for Safety and Preservation of Structures King Saud UniversityRiyadhSaudi Arabia Department of Mechanical and Aerospace Engineering Politecnico di TorinoCorso Duca degli Abruzzi 2410129 TorinoItaly

The buckling of thin-walled structures is presented using the 1D finite element based refined beam theory formulation that permits us to obtain N-order expansions for the three displacement fields over the section *** higher-order models are obtained in the framework of the Carrera unified formulation(CUF).CUF is a hierarchical formulation in which the refined models are obtained with no need for ad hoc *** theories are obtained on the basis of Taylor-type and Lagrange polynomial *** of these theories have been carried out by their applications to studies related to the buckling of various beam structures,like the beams with square cross section,I-section,thin rectangular cross section,and annular *** results obtained match very well with those from commercial finite element softwares with a significantly less computational ***,various types of modes like the bending modes,axial modes,torsional modes,and circumferential shell-type modes are observed.

关键词： Unified beam theory Carrera unified formulation(CUF) Buckling 1D formulation

MgO(001) barrier based magnetic tunnel junctions and their device applications

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Science China(Physics,Mechanics & Astronomy) 2013年第1期56卷 29-60页

作者： HAN XiuFeng ALI syed Shahbaz LIANG ShiHeng State Key Laboratory of Magnetism Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of Sciences

Spintronics has received a great attention and significant interest within the past decades,and provided considerable and remarked applications in industry and electronic information *** spintronics,the MgO based magnetic tunnel junction(MTJ) is an important research advancement because of its physical properties and excellent performance,such as the high TMR ratio in MgO based *** present an overview of more than a decade development in MgO based *** review contains three main sections.(1) Research of several types of MgO based MTJs,including single-crystal MgO barrier based-MTJs,double barrier MTJs,MgO based MTJs with interlayer,novel electrode material MTJs based on MgO,novel barrier based MTJs,novel barrier MTJs based on MgO,and perpendicular MTJs.(2) Some typical physical effects in MgO based MTJs,which include six observed physical effects in MgO based MTJs,namely spin transfer torque(STT) effect,Coulomb blockade magnetoresistance(CBMR) effect,oscillatory magnetoresistance,quantum-well resonance tunneling effect,electric field assisted magnetization switching effect,and spincaloric effect.(3) In the last section,a brief introduction of some important device applications of MgO based MTJs,such as GMR & TMR read heads and magneto-sensitive sensors,both field and current switching MRAM,spin nano oscillators,and spin logic devices,have been provided.

关键词： magnetic tunnel junction (MTJ) tunneling magnetoresistance (TMR) MgO spin transfer torque (STT) Coulombblockade magnetoresistance (CBMR)

Potential Antioxidant Activities Improve Salt Tolerance in Ten Varieties of Wheat (<i>Triticum aestivum</i>L.)

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American Journal of Plant Sciences 2013年第6期4卷 69-76页

作者： Aurangzeb Rao syed Dilnawaz Ahmad syed Mubashar Sabir shahid Iqbal Awan Asad Hussain Shah syed Rizwan Abbas Saima Shafique Fareed Khan Atia Chaudhary Department of Chemistry University of the Poonch Rawalakot Pakistan. Department of Plant Breeding and Molecular Genetics Faculty of Agriculture University of the Poonch Rawalakot Pakistan Department of Plant Breeding and Molecular Genetics Faculty of Agriculture University of the Poonch Rawalakot Pakistan University of Azad Jammu and Kashmir Muzaffarabad Pakistan

The activity of antioxidative enzymes system is affected by salt stress, chlorophyll content (CHL), leaf relative water content (RWC), Na+ and K+ contents, their ratio and some oxidative stress indices were studied in leaves of ten bread wheat cultivarsSehar-06, Lu-26, NARC-09, BARC-09 and Pirsbak-09’(salt-tolerant) and Kaghan-94, Rohtas-90, Soughat-90, Shaheen-94 and Zardana-89’(salt-sensitive), grown under salinity treatments carried out in five levels (1 dS·m-1 as control, 2, 4, 8, 16 dS·m-1) via sodium chloride. Under high salt potency significant increase for activities of antioxidant enzymes such as ascorbate peroxidase (APX) and guiacol peroxidase (GPX), occured in salt tolerant varieties. Meanwhile, under salinity condition the activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and (GPX) in sensitive cultivar were lower than control. Regarding (APX) activity there was no significant difference between salinity and control situation. Under salt stress membrane stability index (MSI) of both cultivars were negatively influenced. Hydrogen peroxide (H2O2) content of salinity sensitive cultivars was higher than control. Salt tolerant varieties had more amounts of K+ content, K+ and Na+ ratio, relative water content, yield and chlorophyll under salt conditions, and sensitive ones recorded higher Na+ content at tillering stage. The mechanism of salt stress might be achieved due to low lipid peroxidation, assumingly lower changes in membrane stability index and evasion of Na+ combination and amplified activity of antioxidant enzymes.

关键词： Antioxidant Enzymes Chlorophyll Content+/Na+ Ratio Relative Water Content Salinity Wheat

Perpendicular magnetic tunnel junction and its application in magnetic random access memory

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Chinese Physics B 2014年第7期23卷 13-21页

作者：刘厚方 syed Shahbaz Ali 韩秀峰 Beijing National Laboratory of Condensed Matter Physics Institute of Physics Chinese Academy of Sciences

Recent progresses in magnetic tunnel junctions with perpendicular magnetic anisotropy （PMA） are reviewed and summarized. At first, the concept and source of perpendicular magnetic anisotropy （PMA） are introduced. Next, a historical overview of PMA materials as magnetic electrodes, such as the RE-TM alloys TbFeCo and GdFeCo, novel tetragonal manganese alloys Mn-Ga, L10-ordered （Co, Fe）/Pt alloy, multilayer film [Co, Fe, CoFe/Pt, Pd, Ni, AU]N, and ultra-thin magnetic metal/oxidized barrier is offered. The other part of the article focuses on the optimization and fabrication of CoFeB/MgO/CoFeB p-MTJs, which is thought to have high potential to meet the main demands for non-volatile magnetic random access memory.

关键词： magnetic random access memory perpendicular magnetic anisotropy spin transfer torque effect,magnetic tunnel junction

Interaction properties of solitons for a couple of nonlinear evolution equations

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Chinese Physics B 2021年第1期30卷 185-190页

作者： syed Tahir Raza Rizvi Ishrat Bibi Muhammad Younis Ahmet Bekir Department of Mathematics COMSATS University IslamabadLahore CampusPakistan Punjab University College of Information Technology University of the PunjabLahorePakistan Neighbourhood of Akcaglan Imarli Street Number 28/426030EskisehirTurkey

We study one-and two-soliton solutions for the Cahn–Allen(CA) equation and the Brethorton equation. The CA equation has broad spectrum of applications especially in anti-phase boundary motion and it is used in phase-field *** the Brethorton equation is a model for dispersive wave systems, it is used to find the resonant nonlinear interaction among three linear modes. We use the Hirota bilinear method to obtain one-and two-soliton solutions to the CA equation and the Brethorton equation.

关键词： Hirota bilinear method soliton interaction evolution equations