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Nuclear Science and Techniques 2017年第12期28卷 170-181页

作者： A.m.el-Khayatt Department of Physics College of Science Al Imam Mohammad Ibn Saud Islamic University (IMSIU) Reactor Physics Department NRC Atomic Energy Authority

Effective atomic numbers for photon energy absorption(ZPEA_(eff)) and their corresponding electron numbers (NPEA_(eff)), and effective macroscopic removal cross sections of fast neutrons(RR) were calculated for 27 different types of three-dimensional dosimeters, four types of phantom.materials, and water. The values of ZPEA_(eff) and NPEA_(eff) were obtained using the direct method for energies ranging from 10 keV to 20 meV. Results are presented relative to water, for direct comparison over the range of examined energies. The effect of monomers that are used in polymer gel dosimeters on the water equivalence is discussed. The relation between Σ_R and hydrogen content was studied. micelle gel dosimeters are highly promising because our results demonstrate perfect matching between the effective atomic number, electron density number, and fast neutron attenuation coefficient of water.

关键词： 3D dosimeters Water equivalence Effective atomic number Photon energy absorption Removal cross section Fast neutrons

Diffusion coefficient of vacancies and jump length of electrons in Co_(1-x)Zn_(x)Fe_(2)O_(4)ferrites

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Journal of Advanced Ceramics 2012年第2期1卷 144-149页

作者： m.el-SAADAWY Physics Department Faculty of ScienceKafrelsheikh UniversityKafrelsheikh CityEgypt

A series of polycrystalline samples of Co_(1-x)Zn_(x)Fe_(2)O_(4)where(x=0.1,0.2,0.3,0.4,0.5 and 0.6)were prepared by the usual ceramic technique.X-ray diffraction patterns confirmed the spinel cubic *** diffusion coefficients of oxygen vacancies were estimated from dc conductivity *** was noticed that the diffusion coefficient decreases with increasing Zn^(2+)*** increase of temperature increases the diffusion of lattice *** Curie temperature,lattice parameter and jump length of electrons were studied as a function of Zn^(2+)*** the correlation between the ionic radius and the radii of octahedral and tetrahedral sites,the theoretical lattice parameters were calculated and suggested cation distribution for the given ferrites was determined.

关键词： diffusion coefficient lattice parameter jump length and jump rate of vacancies Curie temperature cation distribution

CO oxidation and 4-nitrophenol reduction over ceria-promoted platinum nanoparticles impregnated with ZSm-5 zeolite

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Journal of Rare Earths 2022年第8期40卷 1247-1254页

作者： Zeinhom.m.el-Bahy mohammed T.Alotaibi Salah m.el-Bahy Department of Chemistry Faculty of ScienceAl-Azhar UniversityNasr City11884CairoEgypt Department of Chemistry Turabah University CollegeTaif UniversityP.O.Box 11099Taif 21944Saudi Arabia

Active new ceria-promoted platinum supported on ZSm-5 catalysts were prepared and characterized by X-ray diffraction(XRD),Fourier transform infrared spectra(FTIR),transform electron microscopy(TEm),temperature programmed desorption(TPD),and FTIR of CO *** samples were prepared by the incipient wetness impregnation method and calcined at 500℃.The XRD patterns and FTIR spectra prove that the zeolite framework is kept unaltered after metal *** images prove the presence of Pt nanoparticles with particle size starting from 14 to 27 *** FTIR data suggest the formation of Pt-O-Ce ***-situ FTIR of CO adsorption over reduced samples proves the presence of Pt~0 only,and no Pt^(n+)-CO species are *** prepared catalysts were tested in both oxidation reaction(CO oxidation) in the gas phase and in reduction reaction(4-nitrophenol reduction) in the aqueous ***,CO oxidation by O_(2) results in the formation of a CO_(2) peak at 2347 cm^(-1) as the only CO oxidation product in the studied frequency *** intensity of the CO_(2) peak increases after the addition of Ce,and it is 4 times higher in Pt_(1) Ce_(0.5)ZSm-5 than that in the Ce-free *** to the FTIR data and previous reports,the increase in the catalytic activity may be due to the formation of Pt-O-Ce ***,Ce-promoted Pt_(1) ZSm5 also exhibits enhanced catalytic activity towards the reduction of 4-nitrophenol to 4-aminophenol by NaBH_(4) in the aqueous *** first-order rate constant of the reduction increases ≈13 times after incorporating equal ratios of Pt and Ce(Pt_(1) Ce_(1)ZSm-5),and the activation energy(E_(a)) decreases to 40% of that in the reaction over Pt_(1) ZSm-5.

关键词： 4-Nitrophenol CO oxidation TPD-CO Platinum-cerium ZSm-5 Rare earths

Physical and Dielectric Properties of Some Nonionic Surfactants

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Journal of materials Science & Technology 1998年第4期14卷 361-367页

作者： el-Anwar, I.m. el-Henawii, S.A. National Research Center Dokki Cairo Egypt Faculty of Science Helwan University Egypt

Fatty acid esters have been prepared by reacting the acid C//1//8 with polyethylene glycols having varying numbers of oxyethylene units (4-88 units) by the direct esterification reaction method. Surface and interfacial tensions were studied at various experimental conditions, including, concentration, temperature and chemical constitution of the surfactant. Critical micelle concentrations (CmC), surface excess and residual area occupied by each surface active agent molecule A have been calculated by using Gibb's equations. CmC values range from 10 to 55 multiplied by 10** minus **5 mole/L for all studied agents, while the residual area occupied by each molecule varies from 0.6 to 1.5 nm**2. Variation of CmC of some of these agents with temperature have been also examined and the obtained data were used to calculate the heat of micellization delta H//m and the entropy change during micellization delta S//m. Values of delta H//m vary from 14.63 kJ/mole to 2.717 kJ/mole depending on the chemical constitution of the agent under consideration. The apparent dipole m.ments mu of three surfactant were measured following the Headstrand's method. (Edited author abstract) 23 Refs.

关键词： Surface active agents

Neutron and Ion Beams Emitted from Plasma Focus (112.5 J) Device

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Plasma Science and Technology 2010年第1期12卷 1-5页

作者： G.m.el-ARAGI Plasma Physics and Nuclear Fusion Department Nuclear Research Center

Preliminary results of recent experiments performed within the mather-type 112.5 J plasma focus device are presented. The ion beams from the focus device operated with deuterium filling at 1 mbar were registered using CR-39 solid state nuclear track detectors （SSNTD） and a Faraday cup detector for time-resolved measurements. The time-resolved neutron emission from the focus region measurements was detected with a photomultiplier tube （IP-28） optically coupled with a plastic scintillator NE 102.

关键词： plasmas neutron scintillator detectors photomultiplier Faraday

Long-term changes in sea surface temperature(SST)within the southern Levantine Basin

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Acta Oceanologica Sinica 2021年第3期40卷 27-33页

作者： Tarek m.el-Geziry Laboratory of Physical Oceanography Division of Marine EnvironmentNational Institute of Oceanography and Fisheries(NIOF)Alexandria21556Egypt

Knowledge of sea surface temperature(SST)behaviour is vital for long-term climate *** study highlights essential outcomes about the distinguishable and unsurprising warming of the SST along the southern border of the Levantine *** analysis is based on monthly SST data for the period *** southern Levantine Basin has undergone SST increase,during the last 71 *** this study,a consistent warming trend has been found for the analysed SST data series,with a rate of 0.04℃/a,i.e.,0.4℃/(10 a).From 1975 to 1991 the mean annual SST was 17.1℃,and this increased to be 19.2℃,over the period *** revealed two opposite trends of variability:a decreasing trend(−0.06℃/a)over the period 1975-1991,and an increasing trend(0.2℃/a)from 2002 to *** the period 1948-2018,positive mean annual SST anomalies had an average of 1.8℃,and negative anomalies had an average of−1.1℃.The lowest SST total increase was found from January to April,with values about 0.03℃,while the highest warming appeared from June to *** driving mechanisms behind the SST changes need to be more investigated,to understand the future trends and impacts of climate change in the Levantine Basin.

关键词： mediterranean Sea Levantine Basin sea surface temperature anomaly trends warming

Effects of Contents of multiwall Carbon Nanotubes in Polyaniline Films on Optical and electrical Properties of Polyaniline

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Chinese Physics Letters 2016年第11期33卷 116-119页

作者： N.Bafandeh m.m.Larijani A.Shafiekhani m.R.Hantehzadeh N.sheikh Department of Physics Science and Research BranchIslamic Azad University Nuclear Radiation Applications Research School Nuclear Science and Technology Research Institute Physics Department Alzahra University School of Physics Institute for Research in Fundamental Sciences

We investigate the effects of different contents of multiwall carbon nanotubes （mWCNTs） on optical and electrical properties of polyaniline （PANI）. The mWCNTs/PANI composites are deposited on glass substrates coated with indium tin oxide （ITO） by the spin-coating technique. The scanning electron microscopy shows that nanotubes are coated with the PANI layer and x-ray diffraction patterns show that all deposited composite films have an amorphous character. The analysis of a UV-vis spectrophotometer indicates the blue shift of the absorbance peak and a decrease in optical band gap value by the enhancement of the CNT content in the PANI matrix while the Urbach energy increases. The Raman spectrum shows the blue shift 1404→1417cm^-1 and photoluminescence spectra show an increase in the intensity of characteristic PANI peak at 436 nm with the increasing CNT content.

关键词： PANI of CNT in CNTs on

Thiolsulfonate functionalized polystyrene resin:Preparation and application in the isolation and identification of electrophilic mutagens

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Journal of Environmental Sciences 2007年第12期19卷 1520-1527页

作者： Wu el Robert m. Carlson Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China Department of Chemistry University of Minnesota-Duluth Duluth MN 55812 USA

A new approach for isolation and identification of elecrtophilic mutagens from complex matrix was developed. Thiosulforfic anion was immobilized onto polystyrene beads and used as separation media. Potassium polystyryl-thiosulfonate, prepared from polystyryl- sulfonyl chloride and KHS, was observed to selectively react with model electrophilic mutagens such as alkyl halides, ct-chloroketones and α-chloroesters to produce polystyryl-thiosulfonlc esters. After separation from other nonreactive organic compounds, the beads then reacted with ethanethiol to produce unsymmetrical ethyl disulfides which are easily detected by GC/mS. For one mutagenic compound, only one unsymmetrical disulfide was found to contain its structure part. Thus, the structure of the parent mutagens could be deduced from that of the unsymmetrical disulfides. The degree of functionalization of the potassium polystyryl-thiosulfonate resin was 1.11 mmol/g. Its reactivity was discussed and its recycling method was reported here.

关键词： functionalized polystyrene potassium polystyryl-thiosulfonate unsymmetrical ethyl disulfides electrophilic mutagens

Yttria Tetragonal Zirconia Biomaterials:Kinetic Investigation

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Journal of materials Science & Technology 2011年第4期27卷 332-337页

作者： Ezzat S.elshazly S.m.el-Hout m.el-Sayed Ali Department of mechanical Engineering Virginia Commonwealth University Deptartment of metallurgy Nuclear Research CenterAtomic Energy Authority

The low temperature aging behavior of polycrystalline tetragonal zirconia was investigated to explore the effects on phase transformation occurring during the process. XRD analysis was conducted for the phase identification and the tetragonal to monoclinic phase transformation was determined. The aging of tetragonal zirconia polycrystals doped with 3 mol% Y203 triggers tetragonal to monoclinic phase transformation on the surface of the specimen only, while the penetration inside the bulk of the specimen is very limited. A slight decrease in the mechanical properties was also observed after aging for 40 h. The transformation kinetics show a nucleation and growth mechanism on the specimen surface to be dominant in the low temperature aging in water environment.

关键词： Low temperature degradation 3Y-TZP Kinetics

Processing of Ceramic Based Nanocomposite Usingα-Al_2O_3 Powder and FeCl_2 Solution as Starting materials

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Journal of materials Science & Technology 2007年第6期23卷 837-842页

作者： mohamed m.el-Sayed Seleman Department of materials and metallurgical Engineering Faculty of Petroleum and Mining EngineeringPost Code 43721SuezEgypt

Alumina-iron nanocomposite powders were prepared by a two-step process. In the first step, α-Al2O3-FeCl2 powder mixture was formed by mixing α-Al2O3 powders with FeCl2 solution followed by drying. In the second step, the FeCl2 in the dry power mixture was selectively reduced to iron particles. A reduction temperature of 750℃ for 15 min in dry H2 was chosen based on the thermodynamic calculations. The concentration of iron in FeCl2 solution was calculated to be 20 vol. pct in the final composite. Two techniques were used to produce composite bulk materials. The Al2O3 nanocomposite powders were divided to two batches. The first batch of the produced mixture was hot pressed at 1400℃ and 27 mPa for 30 min in a graphite die. To study the effect of oxygen on the Al2O3/Fe interface bonding and mechanical properties of the composite, the second batch was heat treated in air at 700℃ for 20 min to partially oxidize the iron particles before hot pressing. Characterization of the composites was undertaken by conventional density measurements, X-ray diffractometry （XRD）, scanning electron microscopy （SEm）, transmission electron microscopy （TEm） and electron probe micro analysis （EPmA）. The suggested processing route （mixing, reduction and hot pressing） produces ceramic-metal nanocomposite much tougher than the pure Al2O3. The fracture strength of the produced Al2O3/Fe nanocomposite is nearly twice that of the pure Al2O3. The presence of spinel phase, FeAl204, as thick layer around the Fe particles in the Al2O3 matrix has a detrimental effect on interfacial bonding between Fe and AI203 and the fracture properties of the composite.

关键词： Ferrous chloride Reduction Alumina-iron nanocomposite Spinel phase