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Assembly of functional carboxymethyl cellulose/polyethylene oxide/anatase TiO_(2) nanocomposites and tuning the dielectric relaxation, optical, and photoluminescence performances

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Journal of Semiconductors 2024年第7期45卷 26-38页

作者： Asmaa M.Ismail Abeer A.Reffaee Fawzy G.El Desouky Spectroscopy Department Physics Research InstituteNational Research CentreGizaCairo 12622Egypt microwave physics and dielectrics Department National Research CentreDokkiCairoEgypt Solid State physics Department Physics Research InstituteNational Research CentreGizaCairo 12622Egypt

Nanocomposite films consisting of carboxymethyl cellulose,polyethylene oxide(CMC/PEO),and anatase titanium diox-ide(TO)were produced by the use of sol-gel and solution casting ***2 nanocrystals were effectively incorporated into CMC/PEO polymers,as shown by X-ray diffraction(XRD)and attenuated total reflectance fourier transform infrared(ATR-FTIR)*** roughness growth is at high levels of TO nanocrystals(TO NCs),which means increasing active sites and defects in CMC/*** differential scanning calorimetry(DSC)thermograms,the change in glass transition temperature(Tg)val-ues verifies that the polymer blend interacts with TO *** increment proportions of TO NCs have a notable impact on the dielectric performances of the nanocomposites,as *** electrical properties of the CMC/PEO/TO nanocomposite undergo significant *** nanocomposite films exhibit a red alteration in the absorption edge as the concentration of TO NCs increases in the polymer *** decline in the energy gap is readily apparent as the weight percentage of TO NCs *** photoluminescence(PL)emission spectra indicate that the sites of the luminescence peak maximums show slight variation;peaks get wider,while their intensities decrease dramatically as the concentration of TO *** nanocomposite materials show potential for multifunctional applications including optoelectronics,antireflection coatings,pho-tocatalysis,light emitting diodes,and solid polymer electrolytes.

关键词： anatase TiO_(2) CMC/PEO nanocomposites optical photoluminescent electrical optoelectronics

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Study of the behaviour of the dielectric constant in Cu,Fe:BaTiO_3

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Journal of Zhejiang University-Science A(Applied physics & Engineering) 2008年第3期9卷 429-434页

作者： Alioune OUEDRAOGO Kalifa PALM Issaka OUEDRAOGO Guy CHANUSSOT Laboratory of Applied Organic Chemistry and physics UFR/SEA University of Ouagadougou BP 7021 Ouagadougou Burkina Faso Laboratory of dielectrics University of Dijon 21000 Dijon France)

In this work we study the behaviour of the dielectric constant of BaTiO3 single crystals doped with Cu and Fe for different ion percentages, particularly, the influence of these hetemvalent substitutions on the ferroelectric-paraelectric phase transition whose temperature is found at Tc=120℃ for pure samples. The dielectric constant e in terms of temperature shows that the Curie temperature decreases when the quantity of impurities increases and presents a broadening and flattering of the maximum oft（T） within higher values, with the transition becoming more and more diffuse. It is interesting to have a material with very high permittivity （high-k） because of its capacity to store an important quantity of electric charges. The t anisotropy and the Curie-Weiss law are also verified with a good ratio between the slopes ofε^-l（T） from both sides of the transition, leading to a Curie constant： C= 13 × 10^4 K for BaTiO3：1.6%Fe in the polar phase. BaTiO3 is a displacive ferroelectric going through a first-order phase transition. The substitutions have an effect on the dynamics of the perovskite lattice. They induce charges transfer to Ti and a diminution of elastic forces in BaTiO3. Then we discuss the transition but on the nature of the material. fact that the maximum of permittivity does not depend on the phase

关键词： Phase transition Ferroelectric BaTiO3 Remeika single crystals Dielectric constant Curie constant

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Structural and dielectric properties of prepared PbS and PbTe nanomaterials

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Journal of Semiconductors 2018年第12期39卷 52-59页

作者： A.A.hzab Azza A.Ward G.M.Mahmoud Eman M.El-Hanafy H.El-Zahed F.S.Terra Solid State physics Department Physical Research DivisionNational Research CentreGizaEgypt microwave physics and dielectrics Department Physical Research DivisionNational Research CentreGizaEgypt University Girls College for Arts Scienceand EducationAin Shams UniversityHelioplesCairoEgypt

In this work, PbS and PbTe nanomaterials with various morphologies were synthesized by a hydrothermal method. The structural properties were investigated by using X-ray diffraction(XRD) and corresponding scanning electron microscopy together with their EDX analysis. Both the PbS and PbTe nanomaterials possess good polycrystalline structure. The crystallite size, determined from the XRD data, of PbS is 5 nm whereas the corresponding value of PbTe is 2.69 nm. SEM micrographs reveal that the prepared PbS nanomaterial has starshaped structures, micro-flowers, some cubes, and semi-dendrites, whereas PbTe has semi-flower structures. Additionally, the dielectric properties have been studied in a broad frequency range from 0.1 Hz up to 1 MHz at temperatures from 298-423 K. The real and imaginary parts of the complex dielectric constant ε' and ε" of PbTe are comparatively higher than those of PbS. Moreover, the dielectric data were analyzed on the basis of the electric modulus.

关键词： dielectric properties PbS PbTe SEM EDX electric modulus

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Effect of SrO on the Structure of Apatite and Wollastonite Phases of Na2O-CaO-SiO2-P2O5Glass System

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New Journal of Glass and Ceramics 2021年第2期11卷 45-56页

作者： Gomaa El Damrawi Rawya Mhammed Ramadan Mohamed El Baiomy Glass Research Group Physics Department Faculty of Science Mansoura University Mansoura Egypt microwave physics and dielectrics Department Physics Research Division National Research Centre Cairo Egypt

Glasses in the system 24.5Na2O·24.5CaO·6P2O5·xSrO·(45-x)SiO2 have been studied in the composition region of x = 0 - 15 mol%. The as prepared glasses are transparent and have an amorphous network structure. On the otherhand, heat treated glasses are transformed to opaque white glass ceramic characterized by their highly crystalline network structure. Crystalline apatite (calcium phosphate, Ca3(PO4)2, wollastonite (calcium silicate, CaSiO3), and strontium calcium phosphate Ca2Sr(PO4)2 are the main well-formed cry

关键词： Structure Physical Properties Gasses Glass Ceramics

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Weakly interacting spinor Bose–Einstein condensates with three-dimensional spin–orbit coupling

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Chinese physics B 2016年第4期25卷 63-68页

作者：宋淑伟孙蕊赵洪王暄韩宝忠 State Key Laboratory Breeding Base of dielectrics Engineering Harbin University of Science and Technology Key Laboratory of Engineering dielectrics and Its Application Ministry of Education Harbin University of Science and Technology College of Electrical and Electronic Engineering Harbin University of Science and Technology

Starting from the Hamiltonian of the second quantization form, the weakly interacting Bose-Einstein condensate with spin--orbit coupling of Weyl type is investigated. It is found that the SU（2） nonsymmetric term, i.e., the spin-dependent interaction, can lift the degeneracy of the ground states with respect to the z component of the total angular momentum Jz, casting the ground condensate state into a configuration of zero Jz. This ground state density profile can also be affirmed by minimizing the full Gross-Pitaevskii energy functional. The spin texture of the zero Jz state indicates that it is a knot structure, whose fundamental group is 7173 （M） ≌π3 （S2） = Z.

关键词： Bose-Einstein condensate spin-orbit coupling knot

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The Effect of the Semiconductive Screen on Space Charge Suppression in Cross-Linked Polyethylene

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Chinese physics Letters 2014年第10期31卷 112-115页

作者：李琳宋伟王暄雷清泉 State Key Laboratory Breeding Base of Dielectrics Engineering Harbin University of Science and Technology Harbin 150080 Key Laboratow of Engilneering dielectrics and Its Application (Ministry of Education) Harbin University of Science and Technology Harbin 150080 College of Electrical & Electronic Engineer Harbin University of Science and Technology Harbin 150080

The space charge distributions of cross-linked polyethylene （XLPE） with Borouge＇s BorlinkTM semiconductive screen type LE0550 and LE0595 from a pulsed electro-acoustic method are obtained. The contact interface morphology at the semiconductive screen and the structure of XLPE near the interface are characterized. The dielectric spectrum and the conductivity current of XLPE with the different semiconduetive electrodes are com- pared. The semiconduetive screen changes the structure and the dielectric characteristic of XLPE near the contact interface, which may be the main reason for space charge suppression in XLPE with Borouge＇s type LEO550 semiconduetive screen.

关键词： SPACE charge PULSED electroacoustic methods CROSS-linked polyethylene insulation ELECTRODES ELECTRIC conductivity

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Effect of sulfur doping on the dielectric properties of Sb_(2)Se_(3) system

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Journal of Advanced dielectrics 2019年第1期9卷 1-5页

作者： Ragab Mahani E.A.El-Sayady microwave physics and dielectrics Department National Research Centre 33 EL Bohouth St.(Former EL Tahrir St.)GizaP.O.12622Egypt Solid State physics Department National Research Centre 33 EL Bohouth St.(Former EL Tahrir St.)GizaP.O.12622Egypt

In this paper,we report the effect of sulfur doping on the electrical and dielectric properties of semiconducting Sb_(2)Se_(2)S over wide ranges of temperatures(298–473 K)and frequencies(42–10^(6) Hz).Sb_(2)Se_(2)S system has been prepared by the direct fusion and cooling cycle of a mixture of the constituent elements,in stoichiometric ratio and purity 99.999%,in vacuum-sealed silica tubes.X-ray analysis showed a decrease in the cell parameters a,b and c upon doping with ***,the pure and doped Sb_(2)Se_(3) showed the single orthorhombic phase *** permittivity of Sb_(2)Se_(2)S showed a decrease with increasing frequency due to a decrease in the average bond ***,ac conductivity increased with the frequency increase,obeying the Jonscher’s universal dynamic *** conductivity temperature dependence is well described by the correlated barrier hopping *** activation energy calculated from DC conductivity is found at higher value(0.79 eV)as compared to that reported in the literature for other antimony selenide ***,a new Sb_(2)Se_(2)S compound is suggested which may be useful for electronic devices.

关键词： Antimony selenide permittivity frequency

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Structure and Properties of the Al-Sn-Cu Bearing Alloy under Different Cold Rolling Conditions

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材料科学与工程（中英文B版） 2015年第7期5卷 298-304页

作者： Amira Nassar Alia S. Taha Ahmad Labeeb El Said Abdullatif Gouda Solid State physics Department Physics Research Division National Research Centre Dokki Giza 12622 Egypt Metallurgy Department Nuclear Research Centre Atomic Energy Authority Cairo Egypt microwave physics and dielectrics Physics Research Division National Research Centre Giza 12622 Egypt

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“Frontiers in Dielectric,Piezoelectric and Ferroelectric Materials”A Special Issue in Honour of Professor Xi Yao

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Journal of Advanced dielectrics 2015年第2期5卷 1-2页

作者： Zuo-Guang Ye Journal of Advanced dielectrics

This special issue(SI)of the Journal of Advanced dielectrics(JAD)contains a collection of review articles and research papers which together provide a comprehensive account on the current state of advanced dielectric,piezoelectric and ferroelectric materials and related physics and *** papers were originally presented at a special symposium on“Frontiers in Dielectric and Ferroelectric Materials”that was organized in the framework of the joint 9th Asian Meeting on Ferroelectrics&9th Asian Meeting on Electroceramics(AMF-AMEC-2014),Oct.26–30,2014,Shanghai,*** symposium was co-organized by Yongxiang Li,Wei Ren and Zuo-Guang Ye.

关键词： ferroelectric piezoelectric ceramics

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Metastable magnetic behavior in La_(0.9)Tb_(0.1)MnO_3

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Rare Metals 2017年第7期36卷 596-600页

作者： Wei-Bin Liu Ying-Tang Zhang Zi-Yu Chen Li-Zhu Liu Sheng-Tao Li Tao-Tao Ai Department of physics Beijing University of Aeronautics and Astronautics School of Material Science and Engineering Institute of Functional MaterialShaanxi University of Technology Key Laboratory of Engineering dielectrics and Its Application Ministry of EducationHarbin University of Science and Technology State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong University

The linear and nonlinear magnetizations of La0.9Tb0.1MnO3 at low temperatures were reported in de- tail. The temperature dependence of magnetization shows peaks at 50, 100 and 150 K, respectively. When LaMnO3 is Tb-doped, its magnetic structure exhibits a canted an- tiparallel spin order. This is different from classical antiferromagnetic （AFM） in which the relaxation behavior takes place at about 150 K. At 50 K, Tb-doped LaMnO3 exhibits canonical spin glass behavior, arising from the competition of exchange and super-exchange between spins. The peak at 100 K shows neither spin glass behavior nor canted AFM behavior. Its peak value increases with frequency increasing, and the transition temperature of the peak shifts to higher temperatures with frequency increasing. The study of aging behavior at 100 K shows a periodical variable metastability, which is ascribed to the competition between ferromagnetic （FM）-, AFM- and sinusoidal-order interactions. This work should shed a light on understanding the complex magnetic structure of the perovskite oxides.

关键词： La0.9Tb0.1MnO3 Relaxation behavior Metastability

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