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Dielectric Behavior of modified Cellulose

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Journal of materials Science & Technology 1999年第2期15卷 164-168页

作者： el-Henawii, S.A. Saad, S.m. el-Anwar, I.m. Faculty of Science Helwan University Egypt Chemistry Department Faculty of Science Al-Azhar University Egypt Physical Chemistry Unit of the N.R.C Egypt

The dielectric constants and the dielectric loss, as well as the activation energy of dielectric relaxation of silylated cellulose were measured within the frequency range 10**5 to 10**7 Hz and the temperature range from 10 to 50 degree C. The test samples were activated cellulose with ethylene diamine, with sodium hydroxide and inactivated cellulose before and after silylation. The measurements were carried out using a multi-deka-meter. Cellulose molecules are more activated by treatment with ethylene diamine than with sodium hydroxide. Generally, silylation causes a marked decrease of the dielectric constant and dielectric loss, meanwhile the silylated samples are affected with the pretreatment of linters with sodium hydroxide and ethylene diamine. (Edited author abstract) 28 Refs.

关键词： Cellulose

Structure and Inclination Angle of the Spiral Galaxy m31

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Chinese Physics Letters 2001年第10期18卷 1420-1422页

作者： ma Jun National Astronomical Observatories Chinese Academy of SciencesBeijing 100012 Joint Laboratory of Optical Astronomy Chinese Academy of SciencesBeijing 100012

The mathematical form, the symmetry of the spiral structure, and the projection of the galactic disc on the image of the spiral galaxy m31 have been directly studied. It is found that m31 has two symmetric arms, i.e. the pitch angles of the two arms are nearly equal;these are 7.7° and 8.0°, respectively. Using the method proposed in this letter, the inclination angle of the galactic disc ofm31 is also obtained, which is 77.5° and is in good agreement with previously published results.

关键词： m31 galactic galaxy

Nuclear radiation shielding effectiveness and corrosion behavior of some steel alloys for nuclear reactor systems

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Defence Technology（防务技术） 2019年第4期15卷 621-628页

作者： m.m. Sadawy R.m. el Shazly mining and Petroleum Engineering Department Al-Azhar University Nasr City Cairo 11371 Egypt Physics Department Faculty of Science Al-Azhar University Nasr City Cairo 11884 Egypt

Different types of nuclear parameters and corrosion behavior were deduced for carbon steel(AISI 1018),austenitic(304 SS),and duplex(2507 SS)stainless steel *** types of neutron energies as well as nine gamma ray energy lines(121.78-1407.92 keV)were used to evaluate the macroscopic neutron cross-sections(∑,cm^-1)and mass attenuation coefficients[σ,cm^2·g^-1)of gamma ray *** corrosion behavior was investigated using different electrochemical *** results showed that the stainless-steel alloys had a good attitude than that of carbon steel alloy for neutron and gamma ray parameters,especially the duplex stainless *** calculated values of mass attenuation coefficient using WinXcom computer program(Version 3.1),exhibited a very good agreement with the experimental values of that ***,the results indicated that duplex stainless-steel exhibited corrosion resistance higher than 304 SS and AISI 1018 steel alloys.

关键词： Steel alloys macroscopic cross-section mass attenuation coefficient Passive film Pitting

Formation of Alfvénic supernonlinear waves in a plasma containing double spectral distributed electrons

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Communications in Theoretical Physics 2024年第12期76卷 140-149页

作者： A A el-Tantawy W F el-Taibany S K el-Labany A m Abdelghany Department of Physics Faculty of Science Damietta University Center of Space Research and Its Application Damietta University

The characteristics of nonlinear and supernonlinear Alfvén waves propagating in a multicomponent plasma composed of a double spectral electron distribution and positive and negative ions were investigated. The Sagdeev technique was employed, and an energy equation was derived. Our findings show that the proposed system reveals the existence of a double-layer solution, periodic, supersoliton, and superperiodic waves. The phase portrait and potential analysis related to these waves were investigated to study the main features of existing waves. It was also found that decreasing the electron temperature helps the superperiodic structure to be excited in our plasma model. Our results help interpret the nonlinear and supernonlinear features of the recorded Alfvén waves propagating in the ionosphere D-region.

关键词： Alfvén waves double spectral distribution nonlinear waves Sagdeev method supernonlinear waves

First-principles prediction of the magnetism of 4f rare-earth-metal-doped wurtzite zinc oxide

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Journal of Rare Earths 2014年第8期32卷 715-721页

作者： A.G.el Hachimi H.Zaari A.Benyoussef m.el Yadari A.el Kenz Laboratoire de magnétisme et Physique des Hautes Energies LMPHE (URAC 12) Département de Physique B.P.1014 Faculté des SciencesUniversité Mohammed V-Agdal Institut of Nanomaterials and Nanotechnology Hassan II Academy of Science and Technology Department of Science Moulay Ismail University Faculté Polydisciplinaire

electronic structure and magnetic properties of wurtzite ZnO semiconductor doped with rare earth （RE=La, Ce, Pr, Pm, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb） atoms were studied using spin-polarized density functional theory based on the full-potential linear augmented plane wave （FP-LAPW） method as implemented in the Wien2k code. In this approach the generalized gradient approximation （GGA） was used for the exchange-correlation （XC） potential. Our results showed that the substitution of RE ions in ZnO induced spins polarized localized states in the band gap. moreover, the studied DmSs compounds retained half metallicity at dopant concentration x=0.625%for most of the studied elements, with 100%spin polarization at the Fermi level （EF）. The total magnetic moments of these compounds existed due to RE 4f states present at EF, while small induced magnetic moments existed on other non-magnetic atoms as well. Finally, the energy difference between far and near configurations was investigated. It was found that the room temperature ferromagnetism was possible for RE-doped ZnO at near configuration. Since the RE-RE separation was long enough （far configuration） for magnetic coupling, the system became paramagnetic or antiferromagnetic ground state.

关键词： ZnO rare earths ferromagnetism DmS electronic structure magnetic properties half-metallic RE-doped ZnO FP-LAPW method density functional theory

Radionuclides measurements and mineralogical studies on beach sands, East Rosetta Estuary, Egypt

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Chinese Journal Of Geochemistry 2013年第2期32卷 146-156页

作者： Abd el Wahab m. el Nahas H.A. Physics Department Faculty of Women for Arts Science and Education Ain Shams University Cairo P.O 11757 Egypt Nuclear materials Authority Cairo P.O. Box 530 Egypt

Radiometric measurements were carried out for the beach sands from East Rosetta estuary to determine the activity concentrations of 238 U, 226 Ra, 232 Th, and 40 K, using a Hyper Pure Germanium spectrometer, to estimate the dose rates and radiation hazard indices. The average specific activities are 778.20 Bq/kg for 238 U; 646.89 Bq/kg for 226 Ra; 621.92 and 627.85 Bq/kg for the 222 Rn daughters 214 Pb and 214 Bi respectively. The average specific activity of 232 Th is 1510.25 Bq/kg, while the calculated specific activity for 40 K has an average of 8.41 Bq/kg. The average specific activity of 235 U is 38.61 Bq/kg. The average absorbed dose rate is 1211.36 nGy/h, 20 times higher than the estimated average global primordial radiation of 60 nGy/h and 6 times higher than that of the world range (10-200 nGy/h). The radium equivalent (Ra eq ) values are from 6 to 9 times the recommended value. The internal and external hazard indices (H int , H ex ) indicate that their values are from 6 to 11 times the permissible values of these indices. These higher values may be due to the presence of economic heavy minerals containing radionuclides as zircon and monazite as well as some trace minerals, thorite and uranothorite. The mineralogical study indicates the beach sands contain heavy minerals, zircon, monazite, rutile, ilmenite, leucoxene, magnetite and garnet. The average abundance of zircon is 0.175 wt% ranging from 0.125 wt% to 0.239 wt%, while it is 0.004wt% ranging from 0.001 wt% to 0.007 wt% for monazite. The average abundance is 0.087 wt% for rutile; 2.029 wt% for ilmenite; 1.084 wt% for magnetite; 0.384 wt% for leucoxene and 0.295 wt% for garnet.

关键词：放射性核素海滩砂矿物学核素测量河口平均丰度埃及辐射测量

Petrological and mineralogical characteristics of younger granites and pegmatites in the Wadi Haleifiya area, southeastern Sinai, Egypt

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Chinese Journal Of Geochemistry 2011年第3期30卷 304-316页

作者： el Gharbawy R.I. el Feky m.G. el Galy m.m. el maadawy W.m. Faculty of Science Ain Shams Univeristy Cairo Egypt Nuclear materials Authority P.O. Box 030 Maadi Egypt

This study is concerned with the radioactivity and mineralogy of the younger granites and pegmatites in the Wadi Haleifiya area, southeastern Sinai Peninsula, Egypt. The area is occupied by metasediments, migmatites, older and younger granites. most of these rocks, especially granites, are dissected by mafic and felsic dykes as well as pegmatites. The younger granites are represented by three main varieties: monzogranites, syenogranites and alkali feldspar granites. The monzogranite consists essentially of quartz, plagioclase, potash feldspar and biotite with minor musco-vite. Iron oxide, titanite, zircon and allanite are the main accessory minerals. Syenogranite is massive, medium- to coarse-grained and commonly exhibits equigranular and hypidiomorphic textures. It is made up essentially of potash feldspar, quartz, plagioclase and biotite. Iron oxides, allanite, epidote, titanite, and zircon are accessory minerals. The alkali feldspar granite consists mainly of perthite, quartz, alkali amphibole (arfvedsonite and riebekite), biotite, sub-ordinate plagioclase and aegirine. Iron oxide, zircon and apatite are accessory minerals, whereas chlorite and sas-surite are secondary minerals. The altered monzogranite and pegmatite recorded high radioelement contents. The eU reaches up to 120 (av.=82×10-6) in the altered monzogranite and up to 55 (av.=27×10-6) in the pegmatites. The high radioactivity in the altered monzogranite is due to the presence of thorite, uranothorite and metamict zircon. In the pegmatites, it is re-lated to the presence of uranophane, uranothorite, thorite, zircon, samarskite, monazite, xenotime, magnetite, ilmen-ite, hematite and rutile.

关键词：二长花岗岩矿物学特征西奈半岛伟晶岩东南部岩石学埃及碱长花岗岩

A common property of R(E,F) and B(R^n,R^m) and a new method for seeking a path to connect two operators

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Science China mathematics 2010年第10期53卷 2605-2620页

作者： ma ZhaoFeng ma JiPu Zhejiang Inst Commun Dept Informat & Management Hangzhou 311112 Zhejiang Peoples R China Harbin Normal Univ Tseng Yuan Rong Funct Anal Res Ctr Harbin 150025 Peoples R China

Given two Banach spaces E,F,let B(E,F) be the set of all bounded linear operators from E into F,and R(E,F) the set of all operators in B(E,F) with finite *** is well-known that B(Rn) is a Banach space as well as an algebra,while B(Rn,Rm) for m = n,is a Banach space but not an algebra;meanwhile,it is clear that R(E,F) is neither a Banach space nor an ***,in this paper,it is proved that all of them have a common property in geometry and topology,i.e.,they are all a union of mutual disjoint path-connected and smooth submanifolds (or hypersurfaces).Let Σr be the set of all operators of finite rank r in B(E,F) (or B(Rn,Rm)).In fact,we have that 1) suppose Σr∈ B(Rn,Rm),and then Σr is a smooth and path-connected submanifold of B(Rn,Rm) and dimΣr = (n + m)r-r2,for each r ∈ [0,min{n,m});if m = n,the same conclusion for Σr and its dimension is valid for each r ∈ [0,min{n,m}];2) suppose Σr∈ B(E,F),and dimF = ∞,and then Σr is a smooth and path-connected submanifold of B(E,F) with the tangent space TAΣr = {B ∈ B(E,F) : BN(A)-R(A)} at each A ∈Σr for 0 r methods for seeking a path to connect two operators can hardly apply here.A new method and some fundamental theorems are introduced in this paper,which is development of elementary transformation of matrices in B(Rn),and more adapted and simple than the elementary transformation *** addition to tensor analysis and application of Thom’s famous result for transversility,these will benefit the study of infinite geometry.

关键词： operator of finite rank smooth Banach submanifold matrix

SOmE CONVOLUTION AND INCLUSION PROPERTIES FOR SUBCLASSES OF mEROmORPHIC p-VALENT FUNCTIONS INVOLVING INTEGRAL OPERATOR

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Acta mathematica Scientia 2013年第6期33卷 1749-1758页

作者： R.m.el-ASHWAH Department of mathematics Faculty of ScienceDamietta University

making use of the linear operator Lp^m（λ,e）f（z）=1/z^p＋∞∑k=1[e/e＋λk]^m akz^k-p,where e〉0,λ〉0,p∈N,m∈N0=NUma,z∈U^＊ and f（z）∈∑p,we introduce two subclasses of meromorphic p-valent analytic functions ... 详细信息

关键词： analytic functions meromorphic functions multiplier transformations