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Oxidation Resistance of the Aluminide Coating Formed on Carbon Steels

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Journal of materials Science & Technology 1997年第5期13卷 383-388页

作者： Soliman, H.m. Ohamed, K.e. Abd el-Azim, m.e. Hammad, F.H. metallurgy Dept. Atomic Energy Authority Cairo Egypt

Low and medium carbon steels were aluminized by the pack aluminizing technique using halideactivated pure-Al and Fe-Al packs. The effect of mixture composition, aluminizing temperatureand time and C content of the steel substrate on the structure and thickness of the aluminidelayer, and on the oxidation resistance was investigated. The optimum oxidation resistance canbe achieved with a low carbon steel substrate when the intermetallic phases Fe3Al and FeAlform the surface of the aluminide layer. In this case, the Al concentration at the surface of thealuminide coating is at least ≥15 wt pct. Formation of high Al concentration phases (FeAl3 andFe2Al5) during aluminizing should be avoided as they tend to embrittle the aluminide layer andreduce its oxidation resistance.

关键词： OO Figure Oxidation Resistance of the Aluminide Coating Formed on Carbon Steels

Chemical forms and extractability of iron in sediments of three contrasting lakes of China and UK

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Journal of environmental Sciences 2003年第6期15卷 728-733页

作者： Gibson C.e.,Stewart B.m. Key Laboratory of Terrestrial ecological Process Institute of Applied ecology Chinese Academy of Sciences Department of Agricultural and environmental Science Queen's University Belfast Shenyang 110016 China Newforge Lane Belfast BT9 5PX UK

Iron is a limiting factor for the eutrophication of lakes, especially those lakes that are enriched with phosphorus. extractability of iron in sediments of West Lake and Taihu Lake in China and Lower Lough erne in Northern Ireland of UK was comparatively investigated on the basis of analysing chemical forms of iron using different extractants. It was shown that extractable iron in sediments of the lakes was greatly different using various extractants. Reactive iron or easily released iron such as “active" iron oxides, total free iron oxide and water-soluble iron was not high, only accounting for 0.01%—0.15% of total iron. The efficiency of the extractants for exchangeable iron was decreased in the sequence 0.1 mol/L HCl DTPA+TeA mixed solution > 1 mol/L NH 4OAc > 0.5 mol/L mgCl 2 = 0.5 mol/L CaCl 2. It seems that the complexion of iron by organic matter was not strong because the concentration of organically bound iron was significantly lower than the concentration it was forecasted. extractable iron is not entirely consistent with or dependent on total iron in lake sediments. To a certain extent, phosphate can inhibit the release of iron in sediments of the lakes. The selection of extractants is thus the first key step to evaluate bioavailability of iron in lake sediments.

关键词： iron chemical form extractability lake sediment eutrophication

Dipole (hyper)polarizabilities of neutral silver clusters

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Chinese Physics B 2016年第12期25卷 217-222页

作者： Francisco e Jorge Luiz G m de macedo Departarnento de Fisica Universidade Fedoral do Espirito Santo 29060-900 Vitoria Brazil Unidade Academica de Fisica Universidade Federal de Campina Grande 58429-900 Campina Grande Brazil Faculdade de Biotecnologia ICB Universidade Federal do Para 66075-110 Belem Brazil

At the Douglas-Kroll-Hess （DKI4） level, the B3PW91 functional along with the all-eleclron relativistic basis sets of valence triple and quadruple zeta qualities are used to determine the structure, stability, and electronic properties of the small silver clusters （Agn, n ≤ 7）. The results presented in this study are in good agreement with the experimental data and theoretical values obtained at a higher level of theory from the literature. Static polarizability and hyperpolarizability are also reported. It is verified that the mean dipole polarizability per atom exhibits an odd-even oscillation and that the polarizability anisotropy is directly related to the cluster shape. In this article, the first study of hyperpolarizabilities of small silver clusters is presented. except for the monomer, the second hyperpolarizabilities of the silver clusters are significantly larger than those of the copper clusters.

关键词： B3PW91 functional all-electron basis sets non-relativistic and DKH2 calculations silver clusters,dipole (hyper)polarizabilities

The effect of fractional thermoelasticity on a two-dimensional problem of a mode I crack in a rotating fiber-reinforced thermoelastic medium

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Chinese Physics B 2013年第10期22卷 575-582页

作者： Ahmed e.Abouelregal Ashraf m.Zenkour Department of mathematics Faculty of ScienceMansoura University Department of mathematics Faculty of ScienceKing Abdulaziz University Department of mathematics College of Science and ArtsUniversity of Aljouf Department of mathematics Faculty of ScienceKafrelsheikh University

This article is concerned with the effect of rotation on the general model of the equations of the generalized thermoe- lasticity for a homogeneous isotropic elastic half-space solid, whose surface is subjected to a mode-I crack problem. The fractional order theory of thermoelasticity is used to obtain the analytical solutions for displacement components, force stresses, and temperature. The boundary of the crack is subjected to a prescribed stress distribution and temperature. The normal mode analysis technique is used to solve the resulting non-dimensional coupled governing equations of the problem. The variations of the considered variables with the horizontal distance are illustrated graphically. Some particular cases are also discussed in the context of the problem. effects of the fractional parameter, reinforcement, and rotation on the varia- tions of different field quantities inside the elastic medium are analyzed graphically. Comparisons are made between the results in the presence and those in the absence of fiber-reinforcing, rotating and fractional parameters.

关键词： fiber-reinforced mode-I crack fractional order thermoelasticity theory rotating medium normalmode analysis

eNHANCemeNT OF ReSISTANCe TO OXIDATIVe DeGRADATION OF NATURAL RUBBeR THROUGH LATeX DeGRADATION

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Chinese Journal of Polymer Science 1998年第2期16卷 170-175页

作者： NWANORH K.O. eNYIeGBULAm m.e. School of Physical Sciences ABIA State University P.M.B. 2000 Uturu NigeriaDepartment of Polymer & Textile Engineering Federal University of Technology P.M.B. 1526 Owerri Nigeria

A fully characterised natural rubber latex was subjected to mechanical degradation by stirring at intervals. The resistance to oxidative degradation of the different samples were studied by measuring the Plasticity retention indices (PRI). The results show that there is an enhancement of the PRI from 57% for the undegraded rubber to 79% for the one-hour degraded sample. Further degradation resulted in decrease of PRI as time of degradation increased. Therefore, the one-hour degraded sample is a special rubber with high oxidation resistance which is of great importance in engineering. (Author abstract) 9 Refs.

关键词： Plasticity Rubber Degradation Oxidation Resistance

effects of the partial replacement of La by m(m=Ce,Ca and Sr) in La_(2-x)m_xCuO_4 perovskites on catalysis of the water-gas shift reaction

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Journal of Natural Gas Chemistry 2010年第6期19卷 567-574页

作者： S.S.maluf e.m.Assaf Institute de Química de So Carlos Universidade de So PauloAv.Trabalhador Socarlense400 So CarlosSP 13560-970Brazil

The performance of La2-x m x CuO4 perovskites （where m=Ce,Ca or Sr） as catalysts for the water-gas shift reaction was investigated at 290℃ and 360℃.The catalysts were characterized by eDS,XRD,N2 adsorption-desorption,XPS and *** XRD results showed that all the perovskites exhibited a single phase （the presence of perovskite structure）,suggesting the incorporation of metals in the perovskite *** XPS and XANeS results showed the presence of Cu2＋ on the *** perovskites that exhibited the best catalytic performance were La 2 x Ce x CuO 4 perovskites,with CO conversions of 85% 90%.moreover,these perovskites have higher surface areas and larger amounts of Cu on the *** Ce has a higher filled energy level than the other metals,increasing the energy of the valence band of Ce and providing more electrons for the ***,the La1.80Ca0.20CuO4 perovskite showed a good catalytic performance.

关键词： perovskites water-gas shift reaction lanthanum copper calcium cerium strontium

Impurity effects on electrical conductivity of doped bilayer graphene in the presence of a bias voltage

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Chinese Physics B 2016年第7期25卷 316-323页

作者： e Lotfi H Rezania B Arghavaninia m Yarmohammadi Department of Physics Sanandaj Branch Islamic Azad University Department of Physics Razi University Department of Physics Kermanshah Branch Islamic Azad University Young researchers and elite Club Kermanshah Branch Islamic Azad University

We address the electrical conductivity of bilayer graphene as a function of temperature, impurity concentration, and scattering strength in the presence of a finite bias voltage at finite doping, beginning with a description of the tight-binding model using the linear response theory and Green＇s function approach. Our results show a linear behavior at high doping for the case of high bias voltage. The effects of electron doping on the electrical conductivity have been studied via changing the electronic chemical potential. We also discuss and analyze how the bias voltage affects the temperature behavior of the electrical conductivity. Finally, we study the behavior of the electrical conductivity as a function of the impurity concentration and scattering strength for different bias voltages and chemical potentials respectively. The electrical conductivity is found to be monotonically decreasing with impurity scattering strength due to the increased scattering among electrons at higher impurity scattering strength.

关键词： bilayer graphene Green's function electrical conductivity

effect of weak measurement on quantum correlations

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Chinese Physics B 2020年第11期29卷 174-181页

作者： L Jebli m Amzioug S e ennadifi N Habiballah m Nassik ePTHe Department of PhysicsFaculty of SciencesIbn Zohr UniversityAgadirMorocco Faculty of Applied Sciences Ibn Zohr UniversityAit-MelloulMorocco Abdus Salam International Center for Theoretical Physics Strada Costiera11 I-34151TriesteItaly LHeP-mS Department of PhysicsFaculty of Science Mohammed V UniversityRabatMorocco Department of Physics Ecole Normale Sup´eieure(ENS)Mohammed V UniversityRabatMorocco

We investigate the local quantum uncertainty(LQU)in weak *** expression of weak LQU is explicitly ***,we consider some cases of three special X states,Werner state,circulant two-qubit states,and Heisenberg model via L... 详细信息

关键词： local quantum uncertainty weak measurement weak local quantum uncertainty

Plasma ignition threshold disparity between silver nanoparticle-based target and bulk silver target at different laser wavelengths

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Plasma Science and Technology 2019年第1期21卷 63-71页

作者： A m eL SHeRBINI m m HAGRASS m R m RIZK e A eL-BADAWY Laboratory of Laser and New materials Faculty of Science Cairo University Faculty of engineering Electrical Engineering Department Alexandria University

Plasma ignition threshold of nanoparticle-based and bulk silver targets was measured in air. The plasma was initiated by a Nd:YAG laser at wavelengths of 355, 532, and 1064 nm. The plasma ignition was monitored utilizing the prominent Ag I line at 546.5 nm. Lower ignition thresholds of the nanoparticle-based silver target were estimated at 0.4?±?0.02, 0.34?±?0.04, and 0.27?±?0.035 J cm^(-2) coupled with the different laser wavelengths, respectively. In contrast, the bulk silver target plasma exhibited an order of magnitude higher ignition threshold. A three orders of magnitude enhanced emission intensity from the nano-based target over the bulk target was achieved at lower levels of laser irradiation. A reduction of the thermal diffusion length of the nanosilver was assumed in order to theoretically predict this reduction in the plasma threshold. In addition, the effect of self-reversal on the resonance lines was taken into consideration.

关键词： NeLIBS enhancement nanosilver laser plasma threshold