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On Nearly σ-Embedded Subgroups of Finite Groups

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Algebra Colloquium 2019年第4期26卷 677-688页

作者： muhammad tanveer hussain Chenchen Cao Li Zhang AAIvanov School of Mathematical Sciences University of Science and Technology of China Hefei 230026China School of Mathematics and Statistics Ningbo University NingboZhejiang 315211China Department of Mathematics and Physics Anhui Jianzhu University Hefei 230022China 不详

Let G be a finite group,σ={σi|i∈ I}be some partition of the set of all primes and σ(G)={(σi|σi∩ π(G)≠0}.We say that a subgroup H of G is nearly cr-cmbcdded in G if there exists a cr-permutable subgroup T of G... 详细信息

关键词： finite group cr-permutable subgroup cr-permutably embedded subgroup nearly cr-embedded subgroup supersoluble group

Efficient Simplification Methods for Generating High Quality LODs of 3D Meshes

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Journal of Computer Science & Technology 2009年第3期24卷 604-612,F0003页

作者： muhammad hussain Department of Computer Science King Saud University

Two simplification algorithms are proposed for automatic decimation of polygonal models, and for generating their LODs. Each algorithm orders vertices according to their priority values and then removes them iteratively. For setting the priority value of each vertex, exploiting normal field of its one-ring neighborhood, we introduce a new measure of geometric fidelity that reflects well the local geometric features of the vertex. After a vertex is selected, using other measures of geometric distortion that are based on normal field deviation and distance measure, it is decided which of the edges incident on the vertex is to be collapsed for removing it. The collapsed edge is substituted with a new vertex whose position is found by minimizing the local quadric error measure. A comparison with the state-of-the-art algorithms reveals that the proposed algorithms are simple to implement, are computationally more efficient, generate LODs with better quality, and preserve salient features even after drastic simplification. The methods are useful for applications such as 3D computer games, virtual reality, where focus is on fast running time, reduced memory overhead, and high quality LODs.

关键词： polygonal models simplification LOD modeling multi-resolution modeling

Mammogram Enhancement Using Lifting Dyadic Wavelet Transform and Normalized Tsallis Entropy

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Journal of Computer Science & Technology 2014年第6期29卷 1048-1057页

作者： muhammad hussain Department of Software Engineering King Saud University

In this paper, we present a new technique for mammogram enhancement using fast dyadic wavelet transform （FDyWT） based on lifted spline dyadic wavelets and normalized Tsallis entropy. First, a mammogram image is decom- posed into a multiscale hierarchy of low-subband and high-subband images using FDyWT. Then noise is suppressed using normalized Tsallis entropy of the local variance of the modulus of oriented high-subband images. After that, the wavelet coefficients of high-subbands are modified using a non-linear operator and finally the low-subband image at the first scale is modified with power law transformation to suppress background. Though FDyWT is shift-invariant and has better poten- tial for detecting singularities like edges, its performance depends on the choice of dyadic wavclcts. On the other hand, the nulnber of vanishing moments is an important characteristic of dyadic wavelets for singularity analysis because it provides an upper bound measurement for singularity characterization. Using lifting dyadic schemes, we construct lifted spline dyadic wavelets of different degrees with increased number of vanishing moments. We also examine the effect of these wavelets on mammogram enhancement. The method is tested on mammogram images, taken from MIAS （Mammographic Image Analysis Society） database, having various background tissue types and containing different abnormalities. The comparison with tile state-of-the-art contrast enhancement methods reveals that the proposed method performs better and the difference is statistically significant.

关键词： mammogram enhancement lifting dyadic wavelet transform Tsallis entropy

Computational Fluid Dynamics(CFD) Modeling of Heat Transfer in a Polymeric Membrane using Finite Volume Method

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Journal of Thermal Science 2016年第6期25卷 564-570页

作者： muhammad Ahsan Arshad hussain School of Chemical and Materials Engineering(SCME) National University of Sciences and Technology(NUST)

The efficiency,robustness and reliability of recent numerical methods for finding solutions to flow problems have given rise to the implementation of computational fluid dynamics(CFD) as a broadly used analysis method for engineering problems like membrane separation *** CFD modeling in this study observes steady and unsteady(transient) heat flux and temperature profiles in a polymeric(cellulose acetate) *** study is novel due to the implementation of user defined scalar(UDS) diffusion equation by using user-defined functions(UDFs) infinite volume method(FVM).Some details of the FVM used by the solver are carefully discussed when implementing terms in the governing equation and boundary conditions(BC).The contours of temperature due to high-temperature gradient are reported for steady and unsteady problems.

关键词： unsteady solver scalar polymeric Membrane robustness governing carefully details discretization

Enhancing Dielectric and Mechanical Behaviors of Hybrid Polymer Nanocomposites Based on Polystyrene,Polyaniline and Carbon Nanotubes Coated with Polyaniline

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Chinese Journal of Polymer Science 2016年第12期34卷 1500-1509页

作者： tanveer ul Haq Zia Ahmad Nawaz Khan Majid hussain Ibrar Hassan Iftikhar hussain Gul Department of Materials Engineering School of Chemical and Materials EngineeringNational University of Sciences and Technology

The dielectric and mechanical properties of hybrid polymer nanocomposites of polystyrene/polyaniline/carbon nanotubes coated with polyaniline （pCNTs） have been investigated using impedance analyzer and extensometer. The blends of PS/PANI formed the heterogeneous phase separated morphology in which pCNTs are dispersed uniformly. The incorporation of a small amount of pCNTs into the blend of PS/PANI has remarkably increased the dielectric properties. Similarly, the AC conductivity of PS/PANI is also increased five orders of magnitude from 1.6 × 10^-10 to 2.0×10^-5 ***-1 in the hybrid nanocomposites. Such behavior of hybrid nanocomposites is owing to the interfacial polarization occurring due to the presence of multicomponent domains with varying conductivity character of the phases from insulative PS to poor conductor PANI to highly conductive CNTs. Meanwhile, the tensile modulus and tensile strength are also enhanced significantly up to 55% and 160%, respectively, without much loss of ductility for three phase hybrid nanocomposites as compared to the neat PS. Thereby, the hybrid nanocomposites of PS/PANI/pCNTs become stiffer, stronger and tougher as compared to the neat systems.

关键词： Nanocomposites Carbon nanotubes Dielectric behavior Mechanical properties Polystyrene.

Metallized siligraphene nanosheets （SiC7） as high capacity hydrogen storage materials

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Nano Research 2018年第7期11卷 3802-3813页

作者： Syeda R. Naqvi tanveer hussain Wei Luo Rajeev Ahuja Condensed Matter Theory Group Department of Physics and Astronomy Box 516 Uppsala University S-75120 Uppsala Sweden Applied Materials Physics Department of Materials and Engineering Royal Institute of Technology (ICFH) S-10044 Stockholm Sweden Centre for Theoretical and Computational Molecular Science Australian Institute for Bioengineering and Nanotechnology The University of Queensland Brisbane Old 4072 Australia

A planar honeycomb monolayer of siligraphene （SIC7） could be a prospective medium for clean energy storage due to its light weight, and its remarkable mechanical and unique electronic properties. By employing van der Waals- induced first principles calculations based on density functional theory （DFT）, we have explored the structural, electronic, and hydrogen （H2） storage characteristics of SiC7 sheets decorated with various light metals. The binding energies of lithium （Li）, sodium （Na）, potassium （K）, magnesium （Mg）, calcium （Ca）, scandium （Sc）, and titanium （Ti） dopants on a SiC7 monolayer were studied at various doping concentrations, and found to be strong enough to counteract the metal clustering effect. We further verified the stabilities of the metallized SiC7 sheets at room temperature using ab initio molecular dynamics （MD） simulations. Bader charge analysis revealed that upon adsorption, due to the difference in electronegativity, all the metal adatorns donated a fraction of their electronic charges to the SiC7 sheet. Each partially charged metal center on the SiC7 sheets could bind a maximum of 4 to 5 H2 molecules. A high H2 gravimetric density was achieved for several dopants at a doping concentration of 12.50%. The H2 binding energies were found to fall within the ideal range of 0.2-0.6 eV. Based on these findings, we propose that metal-doped SiC7 sheets can operate as efficient H2 storage media under ambient conditions.

关键词： dean energy functionalization binding characteristics dopants

Proper Conformal Killing Vectors in Kantowski-Sachs Metric

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Communications in Theoretical Physics 2018年第4期69卷 393-398页

作者： Tahir hussain muhammad Farhan Department of Mathematics University of Peshawar Khyber Pakhtunkhwa Pakista

This paper deals with the existence of proper conformal Killing vectors(CKVs) in Kantowski-Sachs *** to some integrability conditions, the general form of vector filed generating CKVs and the conformal factor is presented. The integrability conditions are solved generally as well as in some particular cases to show that the nonconformally flat Kantowski-Sachs metric admits two proper CKVs, while it admits a 15-dimensional Lie algebra of CKVs in the case when it becomes conformally flat. The inheriting conformal Killing vectors(ICKVs), which map fluid lines conformally, are also investigated.

关键词： conformal killing vectors killing vectors Kantowski-Sachs metric

Moirépatterns arising from bilayer graphone/graphene superlattice

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Nano Research 2020年第4期13卷 1060-1064页

作者： Hu Li Raffaello Papadakis tanveer hussain Amir Karton Jiangwei Liu Key Laboratory of High Efficiency and Clean Mechanical Manufacture School of Mechanical EngineeringShandong UniversityJinan 250061China School of Electrical and Electronic Engineering University of ManchesterM139PL ManchesterUK Department of Chemistry Angstrdm LaboratoryUppsala University75121 UppsalaSweden School of Molecular Sciences University of Western AustraliaWA6009 PerthAustralia

Moirépatterns from two-dimensional(2D)graphene heterostructures assembled via van der Waals interactions have sparked considerable interests in physics with the purpose to tailor the electronic properties of *** we report for the first time the observation of moire patterns arising from a bilayer graphone/graphene superlattice produced through direct single-sided hydrogenation of a bilayer graphene on *** to pristine graphene,the bilayer superlattice exhibits a rippled surface and two types of moire patterns are observed:triangular and linear moire patterns with the periodicities of 11 nm and 8-9 nm,*** moire patterns are revealed from atomic force microscopy and further confirmed by following fast Fourier transform(FFT)*** functional theory(DFT)calculations are also performed and the optimized lattice constants of bilayer superlattice heterostructure are in line with our experimental *** findings show that well-defined triangular and linear periodic potentials can be introduced into the graphene system through the single-sided hydrogenation and also open a route towards the tailoring of electronic properties of graphene by various moirépotentials.

关键词： Moire patterns graphone/graphene superlattice atomic force microscopy triangular pattern linear pattern

Performance of hot-mix asphalt using polymer-modified bitumen and marble dust as a filler

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Journal of Traffic and Transportation Engineering(English Edition) 2023年第3期10卷 385-398页

作者： Diyar Khan Rawid Khan muhammad Tariq Khan muhammad Alam tanveer Hassan Department of Civil Engineering University of Engineering and TechnologyPeshawarPakistan Faculty of Transport and Aviation Engineering Silesian University of TechnologyKatowice 40-019Poland Department of Civil Engineering University of Engineering and TechnologyMardanPakistan Department of Built Environment and Architecture London South Bank UniversityLondon SE10AAUK

Marble dust waste powder generated by the marble cutting industry has a high *** this research,the use of marble dust(MD)as a mineral filler substitute in hot mixed asphalt(HMA)was *** Marshall mix design was used to determine the optimum bitumen content(OBC)for all of the *** each of the four MD contents,i.e.,0,2%,4%,and 6%by weight of the total aggregates,four different bitumen percentages were *** results of the Marshall stability test showed that the optimum filler content was 4%*** were prepared with 0 MD in the control mix and varying percentages of MD as an alternate *** addition,MD aided in increasing the Marshall stability,rutting resistance,and permanent deformation and reduced the fatigue life of asphalt *** the percentage of MD increases,the rutting resistance and stiffness at high temperatures both *** the percentage of MD increases,the fatigue life *** resistance in high-temperature conditions can be improved by using MD in HMA as a partial substitute for stone dust(SD).In areas where extensive MD waste is present,MD can be incorporated into HMA mixtures instead of conventional fillers.

关键词： Asphalt mixture Marble dust Wheel tracker test Dynamic modulus test Four-point fatigue beam test