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Quantum spin Hall and quantum valley Hall effects in trilayer graphene and their topological structures

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Chinese Physics B 2017年第12期26卷 481-490页

作者： Majeed Ur Rehman A A abid ICQD Hefei National Laboratory for Physical Sciences at Microscale Department of Physics University of Science and Technology of China Hefei 230026 China Key Laboratory of Geospace Environment(Chinese Academy of Sciences) Department of Geophysics and Planetary Science University of Science and Technology of China Hefei 230026 China

The present study pertains to the trilayer graphene in the presence of spin orbit coupling to probe the quantum spin/valley Hall effect. The spin Chern-number Cs for energy-bands of trilayer graphene having the essence of intrinsic spin-orbit coupling is analytically calculated. We find that for each valley and spin, Cs is three times larger in trilayer graphene as compared to single layer graphene. Since the spin Chern-number corresponds to the number of edge states, consequently the trilayer graphene has edge states, three times more in comparison to single layer graphene. We also study the trilayer graphene in the presence of both electric-field and intrinsic spin-orbit coupling and investigate that the trilayer graphene goes through a phase transition from a quantum spin Hall state to a quantum valley Hall state when the strength of the electric field exceeds the intrinsic spin coupling strength. The robustness of the associated topological bulk-state of the trilayer graphene is evaluated by adding various perturbations such as Rashba spin-orbit （RSO） interaction αR, and exchange-magnetization M. In addition, we consider a theoretical model, where only one of the outer layers in trilayer graphene has the essence of intrinsic spin-orbit coupling, while the other two layers have zero intrinsic spin-orbit coupling. Although the first Chern number is non-zero for individual valleys of trilayer graphene in this model, however, we find that the system cannot be regarded as a topological insulator because the system as a whole is not gaped.

关键词： trilayer graphene quantum spin Hall effect topological insulator quantum phase transition

Liver parasites:A global endemic and journey from infestation to intervention

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World Journal of Gastroenterology 2025年第1期31卷 8-15页

作者： Yumna Shahid Bushra Emman Shahab abid Department of Medicine Section of GastroenterologyAga Khan University HospitalKarachi 75500SindhPakistan Aga Khan Medical College Aga Khan University HospitalKarachi 75500SindhPakistan

Parasites have coexisted with humans throughout history,forming either symbiotic relationships or causing significant morbidity and *** liver is particularly vulnerable to parasitic infections,which can reside in,pass through,or be transported to the liver,leading to severe *** editorial explores various parasites that infect the liver,their clinical implications,and diagnostic considerations,as discussed in the article“Parasites of the liver:A global problem?”.Parasites reach the liver primarily through oral ingestion,mucosal penetration,or the bloodstream,with some larvae even penetrating the *** parasites such as cestodes(Echinococcus),trematodes(Clonorchis,Opisthorchis),nematodes(Ascaris),and protozoa(Entamoeba histolytica)can also cause systemic infections like visceral leishmaniasis,malaria,cryptosporidiosis,and *** infections like clonorchiasis and opisthorchiasis are linked to persistent hepatobiliary inflam.ation,potentially progressing to cholangiocarcinoma,a fatal bile duct cancer,particularly prevalent in Southeast *** global nature of liver parasite infestations is alarming,with hundreds of millions affected ***,control over treatment quality remains *** the significant public health threat posed by these parasites,international medical organizations must prioritize improved diagnosis,treatment,and preventive *** educational efforts and enhancing healthcare provider training are critical steps toward mitigating the global impact of parasitic liver diseases.

关键词： Liver flukes Nematodes Cestodes Trematodes Protozoa Parasites

Selective catalytic reduction of NO by NH3 on cerium modified faujasite zeolite prepared from aluminum scraps and industrial metasilicate

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Journal of Rare Earths 2020年第3期38卷 250-256页

作者： Rahma abid Gerard Delahay Hassib Tounsi Laboratory of Advanced Materials National School of Engineers of SfaxUniversity of SfaxTunisia Institut Charles Gerhardt ENSCM"Advanced Materials for Health and Catalysis"240 Av Professor Emile Jeanbrau34296 MontpellierFrance

This work was devoted to the study of the selective catalytic reduction of NO by NH3 on calcined and hydrothermal treated cerium loaded zeolite *** parent faujasite zeolite Na-F(Si/Al=1.32 and SBET=749 m^2/g) used as support for the preparation of the catalysts was obtained from industrial sodium metasilicate and aluminum *** expected,the NO conversion increases with increasing the percentage of cerium in the structure of the faujasite *** NO conversion into N2 is reached at 400℃at a space velocity of 250 000 h^-*** high conversion is due to the redox shift between Ce^3+/Ce^4+and the strong acid sites related to the rare earth present in the framework that is the key in SCR of NO ***,the highest loaded cerium catalyst retains almost its activity after hydrothermal treatment at 850℃.This higher loading is desirable for both activity and stability provided that two stages of preparation are used to put the Ce ions in the sodalite cages.

关键词： Aluminum scraps Ce-Y NH3-SCR Hydrothermal stability

Complex Network Formation and Analysis of Online Social Media Systems

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Computer Modeling in Engineering & Sciences 2022年第3期130卷 1737-1750页

作者： Hafiz abid Mahmood Malik Faculty of Computer Studies Arab Open UniversityA’aliKingdom of Bahrain

To discover and identify the influential nodes in any complex network has been an important *** is a significant factor in order to control over the *** control on a network,any information can be spread and stopped in a short span of *** targets can be achieved,since network of information can be extended and as well ***,information spread and community formation have become one of the most crucial issues in the world of SNA(Social Network Analysis).In this work,the complex network of twitter social network has been formalized and results are *** this purpose,different network metrics have been *** of the network is provided in its original form and then filter out(different percentages)from the network to eliminate the less impacting nodes and edges for better *** network is analyzed according to different centrality measures,like edge-betweenness,betweenness centrality,closeness centrality and eigenvector *** nodes are detected and their impact is observed on the *** communities are analyzed in terms of network coverage considering theMinimum Spanning Tree,shortest path distribution and network *** is found that these are the very effective ways to find influential and central nodes from such big social networks like Facebook,Instagram,Twitter,LinkedIn,etc.

关键词： Complex network data extraction nodes and edges network visualization social media network main hubs centrality measures

A New Algorithm for a Condenser Design for Large-Scale Nuclear Power Plants in Tropical Region

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Journal of Thermal Science 2020年第5期29卷 1370-1389页

作者： KHAN abid Hossain ISLam Md.Shafiqul Department of Industrial and Production Engineering Jashore University of Science and TechnologyJashore 7408Bangladesh Department of Nuclear Engineering University of DhakaDhaka 1000Bangladesh

This work presents a new velocity search algorithm for designing a condenser of a 1200 MWe large-scale nuclear power plant situated in tropical *** this,the condenser pressure was considered in the range of 7.5-15 kPa while its tube inner diameter was taken as 28 mm with 1 mm tube wall *** longitudinal and transverse condensers with multiple shell tanks and varied shell tank lengths from 8-14 m have been considered in this *** different tertiary coolant temperature rises were chosen as 4°C,8°C and 12°C by considering tropical region average reservoir water temperature range of 28°C to 32°C during *** of tertiary coolant was kept within 0.75-1.5 m/s to ensure sufficient turbulence to avoid erosion-corrosion of the *** simulation has been employed to obtain tube-side pressure drop and convection heat transfer coefficient directly from tertiary coolant inlet velocity using κ-ω turbulent flow model.A new iterative“Velocity-search algorithm”has been developed that focuses on finding the correct tertiary coolant velocity instead of overall heat transfer *** revealed that velocity-search algorithm yielded very close to the important physical and thermal parameters of condenser compared to the existing design data in large scale nuclear power ***-search algorithm has given less number of condenser design physical parameters that meets the velocity acceptance criteria for longitudinal condenser compared to the transverse ***,velocity-search algorithm is found to be more reliable,robust,and consistent for condenser design compared to the conventional design algorithm used in Log-Mean Temperature Difference method.

关键词： nuclear power plant vacuum condenser velocity-search algorithm tropical region

Film Flow of Nano-Micropolar Fluid with Dissipation Effect

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Computer Modeling in Engineering & Sciences 2024年第9期140卷 2487-2512页

作者： Abuzar abid Siddiqui Mustafa Turkyilmazoglu Department of Basic Sciences&Humanities Faculty of Engineering&TechnologyBahauddin Zakariya UniversityMultanPakistan Department of Mathematics Hacettepe UniversityAnkaraTürkiye Department of Medical Research China Medical University HospitalChina Medical UniversityTaichungTaiwanChina

The physical problem of the thin film flow of a micropolar fluid over a dynamic and inclined substrate under the influence of gravitational and thermal forces in the presence of nanoparticles is *** different types of nanoparticle samples are accounted for in this current study,namely gold Au,silver Ag,molybdenum disulfide MoS_(2),aluminum oxide Al_(2)O_(3),and silicon dioxide SiO_(2).Blood,a micropolar fluid,serves as the common base *** exact closed-form solution for this problem is derived for the first time in the *** results are particularly validated against those for the Newtonian fluid and show excellent *** was found that increasing values of the spin boundary condition and micropolarity lead to a reduction in both the thermal and momentum boundary layers.A quantitative decay in the Nusselt number for a micropolar fluid,as compared to a Newtonian one for all the tested nanoparticles,is *** and silver nanoparticles(i)intensify in the flow parameter as the concentration of nanoparticles increases(ii)yield a higher thermal transfer rate,whereas molybdenum disulfide,aluminum oxide,and silicon dioxide exhibit a converse attitude for both Newtonian and micropolar *** reduction in film thickness for fluid comprising gold particles,as compared to the rest of the nanoparticles,is remarkable.

关键词： Thin film flow micropolar fluid nanoparticles molybdenum disulfide inclined substrate

Effect of different catalysts and growth temperature on the photoluminescence properties of zinc silicate nanostructures grown via vapor-liquid-solid method

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Chinese Physics B 2022年第5期31卷 657-665页

作者： Ghfoor Muham.ad Imran Murtaza Rehan abid Naeem Ahmad Department of Physics International Islamic UniversityIslamabad 44000Pakistan

We explore the photoluminescence properties of zinc silicate(Zn_(2)SiO_(4)) nanostructures synthesized by vapor-liquidsolid(VLS)mode of growth using three different catalysts(Sn,Ag,and Mn).Different catalysts significantly influence the growth rate which in turn has an impact on the structure and hence the photoluminescence of the prepared zinc silicate ***_(2)SiO_(4) has a wide bandgap of about 5.5 eV and in its pure form,it does not emit in visible region due to its inner shell electronic transitions between the 3 d5 energy ***,the incorporation of different catalysts(Sn,Ag and Mn)at different growth temperatures into the Zn_(2)SiO_(4) crystal growth kinetics provides wide visible spectral range of photoluminescence(PL)*** analysis shows broad multi-band spectrum in the visible region and distinct colors(red,yellow,green,blue,cyan and violet)are obtained depending on the crystalline structure of the prepared *** allowed transitions due to the effect of different catalysts on zinc silicate lattice offer a huge cross-section of absorption that generates strong *** correlation between the structural and optical properties of the synthesized nanostructures is discussed in *** synthesized photoluminescent nanostructures have potential applications in solidstate lighting and display devices.

关键词： nanostructures vapor-liquid-solid growth mode photoluminescence spectra fluorescence microscopy

Cybernet Model:A New Deep Learning Model for Cyber DDoS Attacks Detection and Recognition

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Computers, Materials & Continua 2024年第1期78卷 1275-1295页

作者： Azar abid Salih Maiwan Bahjat Abdulrazaq Department of Information Technology Technical College of DuhokDuhok Polytechnic UniversityDuhokIraq Department of Computer Science Faculty of ScienceUniversity of ZakhoDuhokIraq

Cyberspace is extremely dynamic,with new attacks arising *** cybersecurity controls is vital for network *** Learning(DL)models find widespread use across various fields,with cybersecurity being one of the most crucial due to their rapid cyberattack detection capabilities on networks and *** capabilities of DL in feature learning and analyzing extensive data volumes lead to the recognition of network traffic *** study presents novel lightweight DL models,known as Cybernet models,for the detection and recognition of various cyber Distributed Denial of Service(DDoS)*** models were constructed to have a reasonable number of learnable parameters,i.e.,less than 225,000,hence the name“lightweight.”This not only helps reduce the number of computations required but also results in faster training and inference ***,these models were designed to extract features in parallel from 1D Convolutional Neural Networks(CNN)and Long Short-Term Memory(LSTM),which makes them unique compared to earlier existing architectures and results in better performance *** validate their robustness and effectiveness,they were tested on the CIC-DDoS2019 dataset,which is an imbalanced and large dataset that contains different types of DDoS *** results revealed that bothmodels yielded promising results,with 99.99% for the detectionmodel and 99.76% for the recognition model in terms of accuracy,precision,recall,and F1 ***,they outperformed the existing state-of-the-art models proposed for the same ***,the proposed models can be used in cyber security research domains to successfully identify different types of attacks with a high detection and recognition rate.

关键词： Deep learning CNN LSTM Cybernet model DDoS recognition

Conceptual design,modeling and compliance characterization of a novel 2-DOF rotational pointing mechanism for fast steering mirror

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Chinese Journal of Aeronautics 2020年第12期33卷 3564-3574页

作者： Muham.ad abid Jingjun YU Yan XIE Abdus SALam Robotics Institute School of Mechanical Engineering and AutomationBeihang UniversityBeijing 100083China School of Aeronautic Science and Engineering Beihang UniversityBeijing 100083China

In this paper,a novel 2-DOF rotational pointing mechanism(RPM)is designed inspired by the guidelines of the graphical *** mechanism integrates with a fast steering mirror(FSM)for compensating pointing errors of a laser *** design intends to achieve an angular travel of±10 mrad and steers a 25 mm mirror aperture.A planar flexure with beam flexures accompanied in parallel with an axial flexure build-up mechanism *** mechanismbased RPM ensures high precision and *** characteristics are established based on the stiffness matrix method for four different planar flexure *** layout with best in-plane rotational compliance is then assessed for performance sensitivity to mechanism dimension parameters and parasitic error,thus informing the design *** stiffness in both the inplane rotational axes and stress is determined based on finite element analysis(FEA).The wire electrical discharge machining(EDM)is employed for developing the proof of concept for the RPM and is then assembled in *** are conducted to determine the rotational stiffness and angular travel about both in-plane rotational *** among theoretical,numerical and experiments reveal excellent linearity of rotational stiffness along the rotational travel *** maximum theoretical error is less than 5.5%compared with FEA while,the experimental error has a mean of 5%and 3%for both rotational axes thus satisfying the intended design requirement.

关键词： Compliant mechanism Finite element analysis Graphical approach Rotational stiffness Sensitivity analysis