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Comparative Study of th. One Dimensional Dielectric and Metallic Ph.tonic Crystals

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Optics and Ph.tonics Journal 2012年第2期2卷 105-112页

作者： arafa h. aly Moh.med Ismaeel Eh.b Abdel-Rah.an Department of Ph.sics Faculty of Sciences Beni-Suef University Beni-Suef Egypt Department of Ph.sics The American University in Cairo New Cairo Egypt YJ-STRC The American University in Cairo New Cairo Egypt

Th. optical transmission properties of two types of ph.tonic crystals h.ve been analyzed by using th. transfer matrix meth.d. Th. first one is th. dielectric ph.tonic crystal (DPC), and th. second is th. metallic ph.tonic crystal (MPC). We found th. dielectric and metallic ph.tonic crystals h.ve different transmission spectra. Th. effect of th. most prameters on th. transmission spectra of th. dielectric and metallic ph.tonic crystals h.s been studied.

关键词： Transmission Metallic Ph.tonic Crystals Dielectric Ph.tonic Crystals Ph.tonic Band Gap

Improve th. Efficiency of Scintillation Detectors Using Reflectors Based on Ph.tonic Crystals Arrays

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Journal of Electromagnetic Analysis and Applications 2014年第2期6卷 25-29页

作者： M. F. Eissa arafa h. aly Ph.sics Department Faculty of Science Beni-Suef University Beni-Suef Egypt.

In th. present work, we designed th. new type of ph.tonic crystals (PCs) as reflectors. Reflections from single layer of Al2O3/MgO PC h.lp us in recapturing th. ligh. th.t does escape from th. scintillation surface. Ph.tonic crystals in one dimension array of Al2O3 and MgO with.silver at periodicities N = 1, 2 and 3 were used as a reflector around th. surface of th. scintillation volume. Scintillation detectors are widely used in nuclear medicine. Th. efficiency is an important parameter for ch.racterizing th. capability of th. detectors. Th. counting efficiency of th. detectors depends on th. ligh. emission induced by radiation. Th. ligh. th.n was converted by th. ph.tomultiplier tube into electrical pulses. Th. efficiency may increase by an amount of 1.64% if MgO-Ag ph.tonic crystals are used at periodicity N = 1 as a reflector.

关键词： TMM Ph.tonic Crystals Scintillation Detectors Radiation Ph.tonic Band Gap

Numerical Studies on Electromagnetic Waves Properties in Metallic-Dielectric Ph.tonic Crystal

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Journal of Electromagnetic Analysis and Applications 2011年第11期3卷 465-470页

作者： arafa h. aly Eh.b Abdel-Rah.an h.ssan S. h.nafey 不详

We h.ve performed numerical analyses to investigate th. propagation ch.racteristics of a simple-one dimensional metallic-dielectric structure. Several different metals h.ve been studied (aluminum, gold, copper, and silver). Copper gives th. smallest absorption and aluminum is more absorptive. We h.ve compared between th. transmittance of th.se structures with.different metals and th. same dielectric material. Also we used th.se different metals with.th. same layer th.ckness, incidence angels, number of layers and th. same electromagnetic waves range.

关键词： Transmittance PC Pasmonic

Effect of nutrition-related infodemics and social media on maternal experience: A nationwide survey in a low/middle income country

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World Journal of Clinical Pediatrics 2024年第1期13卷 93-106页

作者： Marwa M Zein Noh. arafa Mortada h.F El-Sh.brawi Neh.l Moh.mmed El-Koofy Department of Public h.alth.and Community Medicine Cairo UniversityCairo 515211Egypt Department of Pediatric Endocrinology and Diabetes Children's HospitalKasralainy Medical SchoolCairo UniversityCairo 515211Egypt Department of Pediatrics Cairo UniversityCairo 12411Egypt Department of Pediatrics The Children's HospitalCairo UniversityCairo 12411Egypt

BACKGROUND Undernutrition is a crucial cause of morbidity and mortality among ch.ldren in low-or middle-income countries(LMICs).A better understanding of maternal general h.alth. nutrition knowledge,as well as misbeliefs,is h.gh.y essential,especially in such.*** th. current era of infodemics,it is very strenuous for moth.rs to select not only th. righ. source for maternal nutrition information but th. correct information as *** To assess maternal h.alth. nutritional knowledge and nutrition-related misbeliefs and misinformation in an LMIC,and to determine th. sources of such.information and th.ir assessment *** Th.s cross-sectional analytical observational study enrolled 5148 randomly selected Egyptian moth.rs wh. h.d one or more ch.ldren less th.n 15 years *** data were collected th.ough.online questionnaire forms:One was for th. general nutrition knowledge assessment,and th. oth.r was for th. nutritional myth.*** of information and ways of evaluating internet sources using th. Currency,Relevance,Auth.rity,Accuracy,and Purpose test were additionally *** Th. mean general nutrition knowledge score was 29±9,with.a percent score of 70.8%±12.1%(total score:41).Th. median myth.score was 9(interquartile range:6,12;total score:18).Th. primary sources of nutrition knowledge for th. enrolled moth.rs were social media platforms(55%).h.lf of th. moth.rs managed information for currency and auth.rity,except for considering th. auth.r's contact *** th.n 60%regularly ch.cked information for accuracy and *** moth.rs with.significant nutrition knowledge ch.cked periodically for th. auth.r's contact information(P=0.012).Th. nutrition myth.score was significantly lower among moth.rs wh. periodically ch.cked th. evidence of th. information(P=0.016).Moth.rs dependent on th.ir h.alth.are providers as th. primary source of th.ir general nutritional knowledge were less likely to h.ld myth. by 13%(P=0.044).h.wever,usi

关键词： Nutrition Infodemics Maternal knowledge Myth Low/middle income country

Low band gap frequencies and multiplexing properties in 1D and 2D mass spring structures

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Ch.nese Ph.sics B 2016年第11期25卷 333-339页

作者： arafa h.aly Ah.ed Meh.ney Ph.sics Department Faculty of Sciences Beni-Suef University

Th.s study reports on th. propagation of elastic waves in 1D and 2D mass spring *** analytical and computation model is presented for th. 1D and 2D mass spring systems with.different *** enh.ncement in th. band gap values was obtained by modeling th. structures to obtain low frequency band gaps at small ***,th. evolution of th. band gap as a function of mass value is *** attention is devoted to th. local resonance property in frequency ranges with.n th. gaps in th. band structure for th. corresponding infinite periodic lattice in th. 1D and 2D mass spring system.A linear defect formed of a row of specific masses produces an elastic waveguide th.t transmits at th. narrow pass band *** frequency of th. waveguides can be selected by adjusting th. mass and stiffness coefficients of th. materials constituting th. ***,we pay more attention to analyze th. wave multiplexer and DE-multiplexer in th. 2D mass spring *** sh.w th.t two of th.se tunable waveguides with.alternating materials can be employed to filter and separate specific frequencies from a broad band input *** presented simulation data is validated th.ough.comparison with.th. publish.d research.and can be extended in th. development of resonators and MEMS verification.

关键词： multiplexing waveguide tunable separate dimensions devoted verification stiffness validated infinite

Influence of temperature on th. properties of one-dimensional piezoelectric ph.nonic crystals

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Ch.nese Ph.sics B 2018年第9期27卷 342-345页

作者： Ah.ed Nagaty Ah.ed Meh.ney arafa h.aly Ph.sics Department Faculty of Sciences Beni-Suef University

Th. current study investigates th. influence of temperature on a one-dimensional piezoelectric ph.nonic crystal using tunable resonant frequencies. Analytical and numerical examples are introduced to emph.size th. influence of temperature on th. piezoelectric ph.nonic crystals. It was observed th.t th. transmission spectrum of a one-dimensional ph.nonic crystal containing a piezoelectric material（0.7 PMN-0.3 PT） can be ch.nged drastically by an increase in *** resonant peak can be sh.fted toward h.gh.or low frequencies by an increase or decrease in temperature, ***, we deduced th.t temperature can exh.bit a large tuning in th. ph.nonic band gaps and in th. local resonant frequencies depending on th. presence of a piezoelectric material. Such.result can enh.nce th. h.rvesting energy from piezoelectric materials, especially th.se th.t are confined in a ph.nonic crystal.

关键词： ph.nonic crystals resonant modes piezoelectric material th.rmal properties and temperature

Assessment of Radiological h.zards of Sedimentary, Igneous and Sediments Natural Rocks

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World Journal of Nuclear Science and Tech.ology 2024年第2期14卷 131-145页

作者： Wafaa arafa h.la Mah.oud Eman Yousf Ash.y Ash.y Ibrah.m Elaassy Ah.ed Elsersy Faculty of Women Ain Shams University Cairo Egypt Nuclear Material Auth.rity Cairo Egypt Faculty of Education Ain Shams University Cairo Egypt National Institute of Standard Giza Egypt

Gamma-ray spectroscopy based on a 100% efficiency h.per-pure germanium detector was used to evaluate th. activity concentrations of 226Ra, 232Th. and 40K natural radionuclides in sedimentary, conglomerate, igneous and sedi-ments rock samples collected from four different locations in Eastern desert in Egypt. Th. obtained activity concentrations are used to evaluate th. radi-ological h.zards indices, absorbed dose rate, annual effective dose equivalent in air, radium equivalent, external and internal h.zard index, radiation level index, annual gonadal dose equivalent, excess lifetime cancer risk and expo-sure rate. Th. results sh.w th.t 1) th. absorbed dose rate depends on th. rock type, 2) th. annual effective dose equivalent in air in 71% of sample below 20 mSvy-1 (permissible limit for workers), 3) th. conglomerate rocks sh.w low radioactivity level, 4) sedimentary rocks are rich.in radium wh.le igneous rocks are rich.in th.rium and th. sediments rocks are rich.in both.radium and th.rium.

关键词： Gamma Spectrometry Radiological h.zard Indices NORM Sedimentary Conglomerate Igneous Sediments

A different approach.for conformable fractional bioch.mical reaction–diffusion models

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Applied Math.matics(A Journal of Ch.nese Universities) 2020年第4期35卷 452-467页

作者： Anas arafa Department of Math.matics and Computer Science Faculty of SciencePort Said UniversityPort SaidEgypt

Th.s paper attempts to sh.d ligh. on th.ee bioch.mical reaction-diffusion models:conformable fractional Brusselator,conformable fractional Sch.akenberg,and conformable fractional *** is done using conformable residual power series(h.nce-form,CRPS)tech.ique wh.ch.h.s indeed,proved to be a useful tool for generating th. ***,CRPS is an effective meth.d of solving nonlinear fractional differential equations with.greater accuracy and ease.

关键词： Brusselator model Sch.akenberg model Gray-Scott model conformable fractional derivatives residual power series meth.d

h.motopy Analysis Meth.d for Solving Biological Population Model

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Communications in Th.oretical Ph.sics 2011年第11期56卷 797-800页

作者： A.A.M.arafa S.Z.Rida h.Moh.med Department of Math.matics Faculty of ScienceSouth Valley University

In th.s paper,th. h.motopy analysis meth.d (h.M) is applied to solve generalized biological *** fractional derivatives are described by Caputo's *** meth.d introduces a significant improvementin th.s field over existing *** obtained using th. sch.me presented h.re agree well with.th. analyticalsolutions and th. numerical results presented in Ref.[6].h.wever,th. fundamental solutions of th.se equations stillexh.bit useful scaling properties th.t make th.m attractive for applications.

关键词： biological populations model fractional calculus h.motopy analysis meth.d Mittag-Leffier function