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Enhanced dielectric and optical properties of nanoscale barium hexaferrites for optoelectronics and high frequency application

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Chinese Physics B 2018年第12期27卷 517-525页

作者： j.mohammed A B Suleiman Tchouank Tekou Carol T H Y Hafeez j.oti Sharma Pradip K Maj. Sachin Godara Kumar A K Srivastava Department of Physics School of Chemical Engineering and Physical Sciences Lovely Professional University Department of Physics Faculty of Science Federal University Dutse SRM Research Institute SRM University Department of Polymer and Processing Engineering Indian Institute of Technology Roorkee Department of Chemistry Guru Nanak Dev University

M-type barium hexaferrites with chemical composition Ba1-xDyxFe12-yCryO19(x = 0.0, 0.1, 0.2, and y =0.0, 0.4, 0.5) were synthesized via sol–gel auto-combustion method. The samples were pre-sintered at 400℃ for 3 h and sintered at 950℃ for 5 h. The changes in the structural, dielectric, and optical properties were studied after the substitution of Dy3+and Cr3+ions. X-ray diffraction(XRD) analysis confirms the formation of single phase hexaferrites with the absence of secondary phase. FTIR analysis gives an idea of the formation of hexaferrites with the appearance of two peaks at 438 cm-1and 589 cm-1. The field emission scanning electron micrographs(FESEM) show a combination of crystallites with large shapes close to hexagonal platelet-like shape and others with rice or rod-like shapes, whereas EDX and elemental analysis confirm the stoichiometry of prepared samples. The calculated band gap from UV-vis NIR spectroscopy spectra was found to decreases with increase in Dy3+–Cr3+substitution. The dielectric properties were explained on the basis of Maxwell–Wagner model. Enhancement of dielectric constant at higher frequencies was observed in all the samples. Low dielectric loss is also observed in all the samples and Cole–Cole plot shows that grain boundary resistance(Rgb) contribute most to the dielectric properties. The prepared samples exhibit properties that could be useful for optoelectronics and high frequency application.

关键词： Maxwell–Wagner model dielectric constant Cole–Cole plot optical band-gap

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Magnetic nanoparticles for environmental and biomedical applications： A review

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Particuology 2017年第1期15卷 1-14页

作者： Leena mohammed Hassan G.Gomaa Doaa Ragab j.sse Zhu Chemical and Biochemical Engineering Department Western UniversityLondonOntario N6A 5B9Canada

Engineered magnetic nanoparticles （MNPs） hold great potential in environmental, biomedical, and clin- ical applications owing to their many unique properties. This contribution provides an overview of iron oxide MNPs used in environmental, biomedical, and clinical fields. The first part discusses the use of MNPs for environmental purposes, such as contaminant removal, remediation, and water treatment, with a focus on the use of zero-valent iron, magnetite （Fe304）, and maghemite （~,-Fe203） nanoparticles, either alone or incorporated onto membrane materials. The second part of this review elaborates on the use of MNPs in the biomedical and clinical fields with particular attention to the application of superparamag- netic iron oxide nanoparticles （SP1ONs）, which have gained research focus recently owing to their many desirable features such as biocompatibility, biodegradability, ease of synthesis and absence of hysteresis. The properties of MNPs and their ability to work at both cellular and molecular levels have allowed their application in vitro and in vivo including drug delivery, hyperthermia treatment, radio-therapeutics, gene delivery, and biotherapeutics. Physiochemical properties such as size, shape, and surface and magnetic properties as well as agglomeration of MNPs and methods to enhance their stability are also discussed.

关键词： Magnetic nanoparticle Water treatment SPION Biomedical application

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Exploring physical features of anisotropic quark stars in Brans-Dicke theory with a massive scalar field via embedding approach

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Chinese Physics C 2022年第4期46卷 185-198页

作者： Abdelghani Errehymy G.Mustafa Youssef Khedif mohammed Daoud Laboratory of High Energy Physics and Condensed Matter(LPHEMaC) Department of PhysicsFaculty of Sciences Aïn ChockHassanⅡUniversity of CasablancaB.P.5366 MaarifCasablanca 20100Morocco Department of Physics Zhejiang Normal UniversityJinhua 321004China Department of Physics Faculty of SciencesUniversity of Ibn TofailB.P.133Kenitra 14000Morocco Abdus Salam International Centre for Theoretical Physics MiramareTrieste 34151Italy

The main aim of this study is to explore the existence and salient features of spherically symmetric relativistic quark stars in the background of massive Brans-Dicke *** exact solutions to the modified Einstein field equations are derived for specific forms of coupling and scalar field functions using the equation of state relating to the strange quark matter that stimulates the phenomenological MIT-Bag model as a free Fermi gas of *** use a well-behaved function along with the Karmarkar condition for class-one embedding as well as j.nction conditions to determine the unknown metric *** radii of strange compact stars viz.,PSR j.416-2230,PSR j.903+327,4U 1820-30,CenX-3,and EXO1785-248,are predicted via their observed mass for different values of the massive Brans-Dicke *** explore the influences of the mass of scalar field m_(ϕ),coupling parameter ωBD,and bag constant B on state determinants and perform several tests on the viability and stability of the constructed stellar ***,we find that our stellar system is physically viable and stable as it satisfies all the energy conditions and necessary stability criteria under the influence of a gravitational scalar field.

关键词： Brans-Dicke gravity karmarkar's condition exact solutions strange stars MIT bag EoS anisotropy

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Explicit solutions to the time-fractional generalized dissipative Kawahara equation

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j.urnal of Ocean Engineering and Science 2024年第4期9卷 348-352页

作者： Marwan Alquran mohammed Ali Omar Alshboul Department of Mathematics and Statistics Jordan University of Science and TechnologyIrbid 22110Jordan

In this paper,the generalized dissipative Kawahara equation in the sense of conformable fractional derivative is presented and solved by applying the tanh-coth-expansion and sine-cosine function *** quadratic-case and cubic-case are investigated for the proposed *** solutions are obtained with highlighting to the effect of the presence of the alternative fractional-derivative and the effect of the added dissipation term to the generalized Kawahara *** graphical analysis is presented to support the findings of the ***,we believe that the obtained results in this work will be important and valuable in nonlinear sciences and ocean engineering.

关键词： Time-fractional Kawahara equation Conformable-derivative Tanh-coth-expansion method Sine-cosine function method

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Mathematical Development and Verification of a Finite Volume Model for Morphodynamic Flow Applications

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Advances in Applied Mathematics and Mechanics 2011年第4期3卷 470-492页

作者： Fayssal Benkhaldoun mohammed Seaıd Slah Sahmim LAGA Universite Paris 1399 Av J.B.Clement93430 VilletaneuseFrance School of Engineering and Computing Sciences University of DurhamSouth RoadDurham DH13LEUK Laboratoire D’ingenierie Mathematique Ecole Polytechnique de TunisieB.P.743-2078 La MarsaTunisia

The accuracy and efficiency of a class of finite volume methods are investigated for numerical solution of morphodynamic problems in one space *** governing equations consist of two components,namely a hydraulic part described by the shallow water equations and a sediment part described by the Exner *** on different formulations of the morphodynamic equations,we propose a family of three finite volume *** numerical fluxes are reconstructed using a modified Roe’s scheme that incorporates,in its reconstruction,the sign of the j.cobian matrix in the morphodynamic system.A well-balanced discretization is used for the treatment of the source *** method is wellbalanced,non-oscillatory and suitable for both slow and rapid interactions between hydraulic flow and sediment *** obtained results for several morphodynamic problems are considered to be representative,and might be helpful for a fair rating of finite volume solution schemes,particularly in long time computations.

关键词： Morphodynamic model shallow water equations sediment transport finite volume method well-balanced discretization

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Intraoperative radiation therapy deserves to be made more readily available to patients

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Chinese j.urnal of Cancer Research 2016年第4期28卷 461-462页

作者： mohammed Keshtgar Norman R.Williams The Breast Unit Royal Free HospitalRoyal Free London Foundation Trust

Whole breast external beam radiotherapy is an effective adj.vant treatment for early breast cancer, and was a key factor in the move from mastectomy to breast-conserving surgery for women with low-risk disease. The logical development from partial surgical removal of the breast is partial breast radiotherapy. Several methods of delivery have been investigated, but as yet none has been widely accepted.

关键词： more Intraoperative radiation therapy deserves to be made more readily available to patients IMRT

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Implementation Study of Dynamic Load Balancing Algorithm of Parallel Tree Computation on Clusters of Heterogeneous Workstation

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j.urnal of Donghua University(English Edition) 2005年第2期22卷 81-86页

作者： mohammed A.M. Ibrahim M.SaifMokbel Faculty of Engineering Department of Software Engineering Taiz University Republic of Yemen Taiz city P. O.Box:6038

The rapid growth of interconnected high performance workstations has produced a new computing paradigm called clustered of workstations computing. In these systems load balance problem is a serious impediment to achieve good performance. The main concern of this paper is the implementation of dynamic load balancing algorithm, asynchronous Round Robin (ARR), for balancing workload of parallel tree computation depth-first-search algorithm on Cluster of Heterogeneous Workstations (COW) Many algorithms in artificial intelligence and other areas of computer science are based on depth first search in implicitty defined trees. For these algorithms a load-balancing scheme is required, which is able to evenly distribute parts of an irregularly shaped tree over the workstations with minimal interprocessor communication and without prior knowledge of the tree’s shape. For the (ARR) algorithm only minimal interprocessor communication is needed when necessary and it runs under the MPI (Message passing interface) that allows parallel execution on heterogeneous SUN cluster of workstation platform. The program code is written in C language and executed under UNIX operating system (Solaris version).

关键词： cluster of workstations parallel tree computation dynamic load balancing performance metrics

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Study the Biochemical Correlation of Insulin Resistance with HbA1c and Sex Hormones in NIDDM Patients/Meisan-Iraq

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j.urnal of Diabetes Mellitus 2017年第4期7卷 302-315页

作者： Adnan j. M. Al-Fartosy Ibrahim M. mohammed Department of Chemistry College of Science University of Basra Basra Iraq

Obj.ctive: The association between type 2 diabetes mellitus and certain endocrine disorders has the paucity of information and limited data in the province of Meisan (southern of Iraq). Hence, in the present study, an attempt was made to investigate the levels of plasma HbA1c, serum insulin resistance and levels of serum sex hormones in men and women of control and type 2 diabetic patients. Also, the present study aimed to explored the correlation coefficient (r) between insulin resistance and level of HbA1c, FSH, LH, Tt, progesterone and estradiol in men and women patients with NIDDM. Methods: One hundred Iraqi volunteers with abdominal obesity were selected in the present study. Fifty diabetic patients with NIDDM (26 men, and 24 women) aged between (37) and (65) years and 50 healthy individuals (25 men, and 25 women) aged between (36) and (65) years considered as control group. Complete medical history was taken from each subj.ct and complete clinical examinations were performed for all volunteers. Then, the two groups were matched for their fasting blood sugar, BMI, insulin hormone;c-peptide, HbA1c, sex hormones and insulin resistance parameters (HOMA2-IR, HOMA%B and HOMA%S) were calculated using HOMA2 calculator software. Results: We found that insulin resistance demonstrated negative correlations (p 0.05) with levels of serum follicle stimulating hormone (FSH), luteinizing hormone (LH), total testosterone, progesterone and estradiol. While, there was a positive and significant correlation (p 0.01) with value of HbA1c in men and women NIDDM patients. Conclusion: We conclude that an increase in the level of insulin resistance is associated with increased level of blood HbA1c and decreased in level of serum sex hormones (FSH, LH, Tt, E2 and progesterone) in men and women of diabetic group. These behaviors might suggest that insulin resistance can be used as a potential biomarker for predicting dysfunction of sex hygiene in NIDDM patients in addition to glycemic co

关键词： Insulin Resistance Biochemical Correlation HbA1c Sex Hormones NIDDM

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Hydrocarbon generating-potential and maturity-related changes of the Khatatba Formation, Western Desert, Egypt

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Petroleum Research 2019年第2期4卷 148-163页

作者： mohammed A.Ahmed Mostafa M.A.Hassan Geology Department Faculty of ScienceMansoura University35516MansouraEgypt Egyptian General Petroleum Corporation CairoEgypt

The petroliferous province of the Western Desert comprises several sedimentary basins with different hydrocarbon potentiality and production *** middle j.rassic Khatatba Formation was proved a potential source rock in some basins and active/effective in *** current study aims to give a comprehensive assessment and evaluation of the potential organic-rich intervals of the Khatatba Formation across j. and j. fields,northeast Abu Gharadig Basin(NEAG).The hydrocarbon generating capability and sourcing of the Khatatba Formation studied through organic geochemistry calibrated with well ***,the efficiency of some widely used plots of geochemistry is re-evaluated according to their accuracy and *** cuttings,thirteen cores and two oil samples obtained from three wells(j.-2,j.-3 and j.-4)were *** samples revealed total organic carbon(TOC)values ranging from 1 to 9 wt%,exhibiting a good-excellent potential source rock.A single sample in the j.-4 well attained a TOC value of 21.3 wt%with a generating potential(represented by S2 parameter)exceeding 146 mgHc/g rock required a special *** of the samples(mainly in the j.-4 well)attained a sufficient level of thermal maturity for hydrocarbon generation with a Tmax up to 449*** vitrinite reflectance(%Ro)values(a common maturity-related indicator)acquired from the j.-4 well ranging between 0.76%and 0.92%.These values are tediously increasing with depth indicating a uniform geothermal *** Khatatba organofacies,with wide variety of kerogen types(I,II,II-S and II/III),contain marine organic matter with a slight terrigenous input,exhibiting anoxic-suboxic environmental ***-source correlations define the organic-rich intervals responsible for charging the accumulated hydrocarbon in the NEAG concession.

关键词： NEAG concession Abu Gharadig Basin Source rock evaluation Khatatba Formation Well logging

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CubeSat Autonomous Orbit Determination Based on Magnetometer and Sun Sensor Data

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Transactions of Nanj.ng University of Aeronautics and Astronautics 2017年第6期34卷 700-709页

作者： Wesam mohammed Elmahy Zhang Xiang Lu Zhengliang Liao Wenhe School of Mechanical Engineering Nanjing University of Science and TechnologyNanking 210094P.R.China

CubeSats have evolved from purely educational tools to a standard platform for technology demonstration,scientific instrumentation and application in less than a *** open the door to new challenges and interplanetary missions which lead to the direct realization of autonomous orbit determination(AOD)which has been investigated before with different integrated sensors combined with various *** these studies were carried out for larger satellites with more accurate *** and sun sensor combined with extended Kalman filter(EKF)are chosen to complete AOD task considering their light *** the purpose of AOD and the computational cost requirements imposed on CubeSats,it is important to develop and apply low cost on-board *** this perspective,a magnetic model based on a table look up is proposed to generate the reference magnetic field with a low computational *** current article the simulations through Matlab and Satellites Tool Kit(STK)especially focus on the accuracy of the AOD system provided by this *** analysis three EKFs are carried out with different calculation models and data *** system based on the proposed model is fully autonomous,low-cost and has moderate-accuracy required by most CubeSats *** AOD system can be applied as main or backup system depending on the space missions′demands.

关键词： CubeSat autonomous orbit determination(AOD) magnetometer sun sensor

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