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Journal of Semiconductors 2014年第7期35卷 1-9页

作者： muhammad Bilal m.shafiq Iftikhar Ahmad Imad Khan Department of Physics University of MalakandChakdaraPakistan

Structural, elastic, electronic and optical properties ofzinc-chalcogenides （viz. ZnX, X = S, Se and Te） are studied in zinc-blende structure under hydrostatic pressure using the full-potential linearized augmented plane wave method. Generalized gradient approximation is used for exchange correlation potentials. Pressure-dependent lattice constants and bulk moduli are obtained using the optimization method. Young＇s modulus, Poisson＇s ratio, internal strain parameter and anisotropy are also calculated. The higher values of Young＇s modulus in comparison to the bulk modulus show that these materials are hard to break. Poisson＇s ratio is computed for the first time for these materials to the best of our knowledge and its values show higher ionic contribution in these materials. modified Becke and Johnson （mBJ） method is used to study band gaps, density of states, dielectric function and refractive index. Electronic study shows direct band gaps convert to indirect band gaps with increasing pressure in the case of ZnS and ZnTe. We compared our results with other theoretical and experimental results. Our results are far better than other theoretical results because mBJ is the best technique to treat Ⅱ-Ⅵ semiconductors.

关键词： semiconductors elastic properties electronic band structures

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Journal of Rare Earths 2018年第10期36卷 1106-1111页

作者： Sardar Ahmad m.shafiq Rashid Ahmad S.Jalali-Asadabadi Iftikhar Ahmad Department of Chemistry University of Malakand Center for Computational materials Science University of Malakand Department of Physics Abbottabad University of Science and Technology Department of Physics Faculty of SciencesUniversity of Isfahan

In this paper, we explored the structural, elastic and mechanical properties of the strongly correlated electron systems, intermetallic Ln-Au（Ln = Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu） in cubic structure,using PF-LAPW method within the density functional theory. Structural properties of these intermetallics were investigated by treating the exchange-correlation potential with the GGA-PBE, GGA-PBEsol and GGA ＋ U. The effectiveness of the U for the structural properties as compared to other methods confirms the strong correlated nature of these compounds and the calculated lattice constants endorse the divalency of Yb. The results demonstrate the stable cubic CsCl structure of these compounds. Bulk modulus, Young＇s modulus, shear modulus, B/G ratio, Cauchy pressure, Poisson＇s ratio, anisotropic ratio,Kleinman parameters and Lame＇s coefficients were studied using the PBEsol to evaluate their importance in various types of engineering applications. The most prominent features of these compounds are their ductility, very high melting points, resistance to corrosion, and anisotropic nature.

关键词： Strongly correlated electron systems Rare-earth monoaurides mechanical properties Ab-initio calculation

Pulsed ion beam-assisted carburizing of titanium in methane discharge

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Chinese Physics B 2010年第1期19卷 247-256页

作者： m.shafiq m.Hassan K.Shahzad A.Qayyum S.Ahmad R.S.Rawat m.Zakaullah Department of Physics Quaid-i-Azam University Department of Physics GC University National Tokamak Fusion Program Natural Sciences and Science Education National Institute of EducationNanyang Technological University

The carburizing of titanium （Ti） is accomplished by utilizing energetic ion pulses of a 1.5 kJ mather type dense plasma focus （DPF） device operated in methane discharge. X-ray diffraction （XRD） analysis confirms the deposition of polycrystalline titanium carbide （TIC）. The samples carburized at lower axial and angular positions show an improved texture for a typical （200）TIC plane. The Williamson-Hall method is employed to estimate average crystallite size and microstrains in the carburized Ti surface. Crystallite size is found to vary from - 50 to 100 nm, depending on the deposition parameters. microstrains vary with the sample position and hence ion flux, and are converted from tensile to compressive by increasing the flux. The carburizing of Ti is confirmed by two major doublets extending from 300 to 390 cm^-1 and from 560 to 620 cm^-1 corresponding to acoustic and optical active modes in Raman spectra, respectively. Analyses by scanning electron microscopy/energy dispersive x-ray spectroscopy （SEm/EDS） have provided qualitative and quantitative profiles of the carburized surface. The Vickers microhardness of Ti is significantly improved after carburizing.

关键词： carbide plasma focus microstructure surface morphology

Investigation of 50 Hz Pulsed DC Nitrogen Plasma with Active Screen Cage by Trace Rare Gas Optical Emission Spectroscopy

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Plasma Science and Technology 2014年第4期16卷 324-328页

作者： A.SAEED A.W.KHAN m.shafiq F.JAN m.ABRAR m.ZAKA-UL-ISLAm m.ZAKAULLAH Department of Physics Gomal University Department of Physics Quaid-i-Azam University Department of Physics Hazara University Mansehra Plasmant Department of Chemistry Univesity of Antwerp campus DriEkin

Optical emission spectroscopy is used to investigate the nitrogen-hydrogen with trace rare gas （4% Ar） plasma generated by 50 Hz pulsed DC discharges. The filling pressure varies from 1 mbar to 5 mbar and the current density ranges from 1 mA-cm-2 to 4 ***-2. The hydrogen concentration in the mixture plasma varies from 0% to 80%, with the objective of identifying the optimum pressure, current density and hydrogen concentration for active species （[N] and IN2]） generation. It is observed that in an N2-H2 gas mixture, the concentration of N atom density decreases with filling pressure and increases with current density, with other parameters of the discharge kept unchanged. The maximum concentrations of active species were found for 40% H2 in the mixture at 3 mbar pressure and current density of 4 ***-2.

关键词： TRG-OES DC glow discharge reactive species

Nitriding molybdenum: Effects of duration and fill gas pressure when using 100-Hz pulse DC discharge technique

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Chinese Physics B 2014年第10期23卷 349-356页

作者： U.Ikhlaq R.Ahmad m.shafiq S.Saleem m.S.Shah T.Hussain I.A.Khan K.Abbas m.S.Abbas Department of Physics Government College University Centre for Advanced Studies in Physics (CASP) Government College University Department of Physics Quaid-i-Azam University Department of Physics GC University Faisalabad

molybdenum is nitrided by a 100-Hz pulsed DC glow discharge technique for various time durations and fill gas pressures to study the effects on the surface properties of molybdenum. X-ray diffractometry （XRD）, scanning electron microscopy （SEm）, and atomic force microscopy （AFm） are used for the structural and morphological analysis of the nitrided layers. Vickers＇ microhardness tester is utilized to investigate surface microhardness. Phase analysis shows the formation of more molybdenum nitride molecules for longer nitriding durations at fill gas pressures of 2 mbar and 3 mbar （1 bar = 105 Pa）. A considerable increase in surface microhardness （approximately by a factor of 2） is observed for longer duration （10 h） and 2-mbar pressure. Longer duration （10 h） and 2-mbar fill gas pressure favors the formation of homogeneous, smooth, hard layers by the incorporation of more nitrogen.

关键词： pulsed DC glow discharge scanning electron microscopy atomic force microscopy microhard-ness

Fault Tolerant Optical mark Recognition

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Computers, materials & Continua 2023年第2期74卷 3829-3847页

作者： Qamar Hafeez Waqar Aslam m.Ikramullah Lali shafiq Ahmad mejdal Alqahtani muhammad shafiq Department of Computer Science&IT The Islamia University of Bahawalpur63100Pakistan Department of Information Sciences The University of EducationLahore54770Pakistan Industrial Engineering Department College of EngineeringKing Saud UniversityP.O.Box 800Riyadh11421Saudi Arabia Department of Information and Communication Engineering Yeungnam UniversityGyeongsan38541Korea

Opticalmark Recognition(OmR)systems have been studied since *** is widely accepted as a data entry *** technology is used for surveys and multiple-choice *** to its ease of use,OmR technology has grown in popularity over the past two decades and is widely used in universities and colleges to automatically grade and grade student responses to *** accuracy of OmR systems is very important due to the environment inwhich they are *** relies on pixel projection or Hough transform to determine the exact answer in the *** techniques rely on majority voting to approximate a predetermined *** performance of these systems depends on precise input from dedicated *** and scanning OmR tables introduces artifacts that make table processing *** observation is a fundamental limitation of traditional pixel projection and Hough transform *** on the type of artifact introduced,accuracy is affected *** classified the types of errors and their frequency according to the artifacts in the OmR *** a major contribution,we propose an improved algorithm that fixes errors due to *** proposal is based on the Hough transform for improving the accuracy of bias correction mechanisms in OmR *** a minor contribution,our proposal also improves the accuracy of detecting markers in OmR *** results show an improvement in accuracy over existing algorithms in each of the identified *** improvement increases confidence in OmR document processing and increases efficiency when using automated OmR document processing.

关键词： Optical mark recognition fault recognition marking system

Stratified magnetohydrodynamic flow of tangent hyperbolic nanofluid induced by inclined sheet

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Applied mathematics and mechanics(English Edition) 2017年第2期38卷 271-288页

作者： T. HAYAT m. mUmTAZ A. shafiq A. ALSAEDI Department of mathematics Quaid-i-Azam University 45320 Islamabad 44000 Pakistan Nonlinear Analysis and Applied mathematics (NAAm) Research Group Department of Mathematics Faculty of Science King Abdulaziz University Jeddah 21589 Saudi Arabia Department of mathematics Preston University Kohat Islamabad Campus Islamabad 44000 Pakistan

This paper studies stratified magnetohydrodynamic （mHD） flow of tan- gent hyperbolic nanofluid past an inclined exponentially stretching surface. The flow is subjected to velocity, thermal, and solutal boundary conditions. The partial differential systems are reduced to ordinary differential systems using appropriate transformations. The reduced systems are solved for convergent series solutions. The velocity, temperature, and concentration fields are discussed for different physical parameters. The results indi- cate that the temperature and the thermal boundary layer thickness increase noticeably for large values of Brownian motion and thermophoresis effects. It is also observed that the buoyancy parameter strengthens the velocity field, showing a decreasing behavior of temperature and nanoparticle volume fraction profiles.

关键词： two-dimensional magnetohydrodynamic (mHD) flow tangent hyperbolicnanofluid mixed convection exponential stretching double stratification inclined sheet

Evolution of plasma parameters in an Ar-N2/He inductive plasma source with magnetic pole enhancement

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Plasma Science and Technology 2017年第2期19卷 34-42页

作者： maria YOUNUS N U REHmAN m.shafiq m NAEEm m ZAKA-UL-ISLAm m ZAKAULLAH Department of Physics Plasma Physics LaboratoryQuaid-i-Azam University45320 IslamabadPakistan Plasma Physics Laboratory Department of PhysicsCOMSATS Institute of Information Technology44000 IslamabadPakistan Department of Physics Faculty of ScienceJazan University114 JazanSaudi Arabia

magnetic pole enhanced inductively coupled plasmas （maPE-ICPs） are a promising source for plasma-based etching and have a wide range of material processing applications. In the present study Langmuir probe and optical emission spectroscopy were used to monitor the evolution of plasma parameters in a maPE-ICP Ar-Na/He mixture plasma. Electron density （ne） and temperature （Te）, excitation temperature （Texc）, plasma potential （Vp）, skin depth （6） and the evolution of the electron energy probability function （EEPF） are reported as a function of radiofrequency （RF） power, pressure and argon concentration in the mixture. It is observed that ne increases while Te decreases with increase in RF power and argon concentration in the mixture. The emission intensity of the argon line at 750.4 nm is also used to monitor the variation of the ‘high-energy tail＇ of the EEPF with RF power and gas pressure. The EEPF has a ‘bi-maxwellian＇ distribution at low RF powers and higher pressure in a pure N2 discharge. However, it evolves into a ‘maxwellian＇ distribution at RF powers greater than 70 W for pure N2, and at 50 W for higher argon concentrations in the mixture. The effect of argon concentration on the temperatures of two electron groups in the ‘bi-maxwellian＇ EEPF is examined. The temperature of the low-energy electron group TL shows a decreasing trend with argon addition until the ‘thermalization＇ of the two temperatures occurs, while the temperature of high-energy electrons Ta decreases continuously.

关键词： maPE-ICP Langmuir probe OES EEPF

mHD stagnation point flow of nanofluid with SWCNT and mWCNT over a stretching surface driven by Arrhenius kinetics

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Applied mathematics(A Journal of Chinese Universities) 2022年第3期37卷 366-382页

作者： Sohail Nadeem.shafiq Ahmad Alibek Issakhov Ibrahim m.Alarifi Department of mathematics Quaid-I-Azam UniversityIslamabad 44000Pakistan Al-Farabi Kazakh National University av.al-Farabi 71050040AlmatyKazakhstan Department of mechanical and Industrial Engineering College of engineering Majmaah UniversityAl-Majmaah 11952RiyadhSaudi Arabia

The intention of the current research is to address the conclusion of non-isothermal heterogeneous reaction on the stagnation-point flow of SWCNT-engine oil and mWCNT-engine oil nanofluid over a shrinking/stretching ***,exemplify the aspect of heat and mass transfer the upshot of magnetohydrodynamics(mHD),thermal radiation,and heat generation/absorption coefficient are *** bvp4 c from matlab is pledged to acquire the numerical explanation of the problem that contains nonlinear system of ordinary differential equations(ODE).The impacts of miscellaneous important parameters on axial velocity,temperature field,concentration profile,skin friction coefficient,and local Nusselt number,are deliberated through graphical and numerically erected tabulated *** solid volume fraction diminishes the velocity distribution while enhancing the temperature ***,the rate of shear stress declines with increasing the magnetic and stretching parameter for both SWCNT and mWCNT.

关键词： heat generation surface reaction CNTs based nanofluid stretching/shrinking sheet thermal radiation

Chaos-Based Cryptographic mechanism for Smart Healthcare IoT Systems

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Computers, materials & Continua 2022年第4期71卷 753-769页

作者： muhammad Samiullah Waqar Aslam Arif mehmood muhammad Saeed Ahmad shafiq Ahmad Adel m.Al-Shayea muhammad shafiq Department of Computer Science&IT The Islamia University of BahawalpurBahawalpur63100Pakistan Department of Computer Science&IT Government Sadiq College Women UniversityBahawalpurPakistan Industrial Engineering Department College of EngineeringKing Saud UniversityP.O.Box 800Riyadh11421Saudi Arabia Department of Information and Communication Engineering Yeungnam UniversityGyeongsan38541Korea

Smart and interconnected devices can generate meaningful patient data and exchange it automatically without any human intervention in order to realize the Internet of Things(IoT)in healthcare(HIoT).Due to more and more online security and data hijacking attacks,the confidentiality,integrity and availability of data are considered serious issues in HIoT *** this regard,lightweight block ciphers(LBCs)are promising in resourceconstrained environment where security is the primary *** prevalent challenge while designing an LBC for the HIoT environment is how to ascertain platform performance,cost,and *** of the existing LBCs primarily focus on text data or grayscale *** main focus of this paper is about securing color images in a cost-effective *** emphasis high confidentiality of color images captured by cameras in resource-constrained smartphones,and high confidentiality of sensitive images transmitted by low-power sensors in IoT *** order to reduce computational complexity and simulation time,the proposed Lightweight Symmetric Block Cipher(LSBC)exploits chaos-based confusion-diffusion operations at the inter-block level using a single *** strength of LSBC is assessed by cryptanalysis,while it is ranked by comparing it to other privacy-preserving *** results show that the proposed cipher produces promising results in terms of key sensitivity and differential attacks,which proves that our LSBC is a good candidate for image security in HIoT.

关键词： IoT healthcare lightweight block cipher symmetric block cipher