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Preparation of epoxy resin/rare earth doped aluminate nanocomposite toward photoluminescent and superhydrophobic transparent woods

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Journal of Rare Earths 2023年第3期41卷 397-405,I0003页

作者： Mehrez E.El-Naggar Sami Ullah S.Wageh M.A.Abu-Saied tawfik a.khattab Dalal Alhashmialameer Manal Abou Taleb E.A.Matter Institute of Textile Research and Technology National Research CenterDokkiCairo16221Egypt Research Center for Advanced Materials Science(RCAMS) King Khalid UniversityP.O.Box 9004Abha61413Saudi Arabia Department of Chemistry College of ScienceKing Khalid UniversityP.O.Box 9004Abha61413Saudi Arabia Department of Physics Faculty of ScienceKing Abdulaziz UniversityJeddah21589Saudi Arabia K.A.CARE Energy Research and Innovation Center King Abdulaziz UniversityJeddah21589Saudi Arabia Polymeric Materials Research Department Advanced Technology and New Materials Research InstituteCity of Scientific Research and Technological Applications(SRTACITY)New Borg El-Arab CityAlexandria21934Saudi Arabia Department of Chemistry College of ScienceTaif UniversityTaif21944Saudi Arabia Department of Chemistry College of Science and HumanitiesPrince Sattam Bin Abdulaziz UniversityAl-kharj11942Saudi Arabia Department of Polymer Chemistry National Center for Radiation Research and Technology(NCRRT)Egyptian Atomic Energy AuthorityNasr CityP.O.Box 7551Cairo11762Egypt Department of Chemistry Faculty of ScienceDamanhour University22111 DamanhourEgypt

A translucent wooden substrate with long-lasting phosphorescence,high photostability and durability,tough surface,ultraviolet protection,high optical transmittance,and superhydrophobicity was *** long-lasting phosphorescent wooden substrate is able to continue emitting light for extended time ***-modified wood(LMW)was immobilized with a solution of epoxy resin(ER)and rare-earth doped aluminate(REDA)phosphor nanoparticles(NPs).For an improved dispersion of pigment,REDA was synthesized in a nanoscale particle size,and characterized by transmission electron microscopy(TEM)to indicate a particle size of 8-14 *** crystal structure of REDA nanoparticles was also proved by X-ray diffraction(XRD).For an improved production of long-persistent phosphorescent colo rless woods,REDA must be well-dispersed in MAA without *** and emissio n,as well as decay and lifetime spectra were *** morphologies of the wooden substrates with different ratios of REDA were investigated by scanning electron microscopy(SEM),X-ray fluorescence(XRF)analysis,Fourier transform infrared spectra(FT-IR),elemental mapping,and energy-dispersion Xray(EDXA).The phosphorescent woods show changes in color from colorless to green under ultraviolet(UV)irradiation,and to yellowish-green in the dark,as proved by the colorimetric parameters of the CIE Lab *** afterglow wood samples display an absorbance band at 365 nm and two phosphorescent bands at 431 and 520 *** UV shielding,photostability,and hydrophobicity were *** increasing REDA ratio,both static contact and slide angles are found to improve in the ranges of147.6°-163.6°and 9°-14°,*** long-lasting photoluminescence is optimized at a REDA ratio of 8%.The present strategy shows a large-scale production approach of multiple functional woods for many potential applications,such as smart glow in the dark windows and safety signs.

关键词： Translucent wood Rare-earth doped aluminate Superhydrophobic Long-lasting light emission Ultraviolet protection

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The Effect of High Power at Microwave Frequencies on the Linearity of Non-Polar Dielectrics in Space RF component

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International Journal of Communications, Network and System Sciences 2015年第2期8卷 11-18页

作者： tawfik Elsayed khattab Department of Electrical Engineering Engineering College King Khalid University Abha Saudi Arabia

In satellite communication systems, there are high power multichannel transmitters and wideband receivers that have shared RF antenna transmission lines because of: 1) large power level difference between the transmitted and received signal;2) limited frequency channels. The harmonics and Passive Intermodulation (PIM) Interference will be generated due to passive non-linearities in the high power transmission path. This can be a serious problem. This paper describes how to determine the signal levels and dominant mechanisms that are associated with non-linear dielectric behavior in this context. A novel measurement system for testing dielectric samples is described and measurement results are provided for commonly used microwave dielectrics.

关键词： Passive Intermodulation PIM Nonlinear Polar Dielectric Harmonics Cavity Resonator

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Multi-Technique Characterization and Conservation of an Ancient Egyptian Fabric from King Khufu First Solar Ship

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International Journal of Organic Chemistry 2021年第3期11卷 128-143页

作者： Eman Nabil tawfik khattab Samir Kamel Restoration laboratory Royal Chariots Museum Cairo Egypt Dyeing Printing and Auxiliaries Department National Research Centre Cairo Egypt Cellulose and Paper Department National Research Centre Cairo Egypt

Textiles are among the most fragile artefacts in the world. They are difficult to preserve even in the best circumstances. Herein, we studied an artefacts fabric of a special nature in terms of usage. Despite the multiple applications of textiles, the piece understudy is one of the unique pieces that the ancient Egyptian used as fenders for King Khufu’s first solar boat, the second-largest discovery in Egypt history. The boat was discovered inside a limestone pit. It was disassembled and arranged in several layers. Four pillows of wrapped fabric were found in the first layer, which was used as boat fenders. This use is a great discovery of the role of textiles in the manufacture of ancient boats. Thus, we conducted tests and analytical studies of those fenders using scanning electron microscopy (SEM) and an optical microscope to identify the type and nature of fibers, spinning method, and aspects of damage. Both energy-dispersive X-ray (EDX) analysis and infrared analysis (FT-IR) were employed to explore the sample’s elemental content and study the functional groups of the fabric. These analytical processes were useful in carrying out the restoration and preservation work necessary for the artefact under study.

关键词： King Khufu Solar Ship Linen Fender Analytical Methods Conservation

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