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Study of Nanodispersed Iron Oxides Produced in Steel Drilling by Contracted Electric-Arc Air Plasma Torch

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Plasma Science and Technology 2008年第3期10卷 352-357页

作者： P.STEfANOV D.GALANOV G.VISSOKOV D.PANEVA b.KUNEV I.MITOV ISMA Ltd. Samokovsko Chaussee Str. 1738 Sofia Bulgaria Institute of Catalysis Bulgarian Academy of Sciences Sofia Bulgaria

The optimal conditions on the plasma-forming gas flowrate, discharge current and voltage, distance between the plasma-torch nozzle and the metal plate surface for the process of penetration in and vaporization of steel plates by the contracted electric-arc air plasma torch accompanied by water quenching, were determined. The X-ray structural and phase studies as well as Mossbauer and electron microscope studies on the samples treated were performed. It was demonstrated that the vaporized elemental iron was oxidized by the oxygen present in the air plasma jet to form iron oxides （wiistite, magnetite, hematite）, which, depending on their mass ra- tios, determined the color of the iron oxide pigments, namely, beginning from light yellow, through deep yellow, light brown, deep brown, violet, red-violet, to black. A high degree of dispersity of the iron oxides is thus produced, with an averaged diameter of the particles below 500 nm, and their defective crystal structure form the basis of their potential application as components of iron-containing catalysts and pigments.

关键词： nanodispersed iron oxides preparation plasma torch

Crack Initiation Mechanism of Z3CN20.09M Duplex Stainless Steel during Corrosion fatigue in Water and Air at 290 °C

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Journal of Materials Science & Technology 2015年第11期31卷 1144-1150页

作者： H.C.Wu b.Yang Y.Z.Shi Q.Gao Y.Q.Wang State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Collaborative Innovation Center of Universal Iron & Steel Technology School of Materials Science and Engineering Anhui University of Technology

The crack initiation mechanism of a Z3CN20.09M duplex stainless steel （DSS） during corrosion fatigue （Cf） in water and air at 290 ℃ was investigated by using a Cf cracking machine and a scanning electron microscopy （SEM）. The cracks were initiated successively at the persistent stip bands （PSbs）, phase boundaries （Pbs） and pitting corrosion points （PCPs） of the specimens when they were tested in water at 290 ℃, while in airat 290 ℃ the cracks were only initiated at the PSbs and Pbs. And the cracks were found mainly to initiate at the PSbs and Pbs when the specimens were tested in water and air at 290 ℃, respectively. The results also reveal that the cracks were likely to be initiated at the first 20% of fatigue life of the specimens tested in water at 290 ℃. However, the cracks were not found until 50% of fatigue life when tested in air at 290 ℃. Moreover, the crack numbers of the specimens tested in water at 290 ℃ were much more than those tested in air at 290 ℃.

关键词： Duplex stainless steel Corrosion fatigue Crack initiation High temperature water

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Impact of grain size,Pr3+ concentration and host composition on non-contact temperature sensing abilities of polyphosphate nano- and microcrystals

1980年

作者： b.H.AMSTEAD PHILLIP f.OSTWALD MYRON L.bEGEMAN原陈健春陈贵东译

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Journal of Rare Earths 2019年第8期37卷 812-818,I0001页

作者： S.Gharouel L.Marciniak A.Lukowiak W.Strek K.Horchani-Naifer M.férid Research Unit of Rare Earth Materials National Research Center in Sciences of MaterialsB.P.95 Hammam-Lif2050Tunisia b Institute of Low Temperature and Structure ResearchPAS Okolna St. 50-422WroclawPoland

In this article,varied praseodymium polyphosphate hosts:MI(Li,Na K)Pr(PO3)4 microcrystals and LiLa1-xPrx(PO3)4(x = 0.01 ^-1)nanocrystals were successfully synthesized by the flux method and the coprecipitation technique,*** size of stoichiometric nanocrystals of LiPr(PO3)4 was tuned by the te mpe rature of thermal treatment in range of 35-145 *** order to dete rmine the most suitable material for the non-contact optical thermometric applications,the temperature sensing measurements were carried out by using luminescence intensity ratio(LIR)of emission bands corresponding to the ^3 P1→ ^3H5 and ^3P0→ ^3 H5 electronic transitions of Pr3+ ions into the 123-423 K temperature *** influence of the host material composition of MⅠ(Li,Na,K)Pr(PO3)4 microcrystals on the sensitivity of luminescent thermometers was *** is found that the sensitivity of lithium praseodymium polyphosphate is the highest of all micropowders under ***,it is found that the nanocrystals reveal much higher relative sensitivity in respect to the microcrystalline *** highest sensitivity of LIR temperature sensing is found for LiPr(PO3)4 nanocrystals(35 nm grain size)in the whole temperature range,reaching 0.283%/K at 164 *** impact of the average grain size on the sensitivity of LIR based thermometers of LiPr(PO3)4 nanocrystals was *** is found that the reduction of the grain size from 145 to 35 nm results in the enhancement of the relative sensitivity from0.156 to 0.240%/K at 223 *** it is found that the high dopant concentration possesses favorable influence on the relative sensitivity of LiLa1-xPrx(PO3)4 nanocrystalline luminescent thermometers.

关键词： Pr^3+ Temperature sensing Luminescence intensity ratio Temperature sensitivity Grain size Dopant concentration

Response of multi-step compound pre-equilibrium reaction cross sections for the(p,n)reactions to forms of optical model parameters

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Nuclear Science and Techniques 2017年第10期28卷 65-70页

作者： felix S.Olise Oludaisi I.Oladunjoye Afis Ajala Sunday D.Olorunfunmi Hezekiah b.Oianiyi Department of Physics and Engineering Physics ObafemiAwolowo UniversityIle-Ife220005Nigeria

In furtherance to improving agreement between calculated and experimental nuclear data, the nuclear reaction code GAMME was used to calculate the multistep compound(MSC) nucleus double differential cross sections(DDCs) for proton-induced neutron emission reactions using the feshbach-Kerman-Koonin(fKK) formalism. The cross sections were obtained for reactor structural materials involving ^(52)Cr(p, n)^(52)Mn,^(56)fe(p,n)^(56)Co, and ^(60)Ni(p, n)^(60)Cu reactions at 22.2 MeV incident energy using the zero-range reaction mechanism. Effective residual interaction strength was 28 MeV, and different optical potential parameters were used for the entrance and exit channels of the proton-neutron interactions. The calculated DDCs were fitted to experimental data at the same backward angle of 150°, where the MSC processes dominate. The calculated and experimental data agree well in the region of pre-equilibrium(MSC) reaction dominance against a weaker fit at the lower emission energies. We attribute underestimations to contributions from the other reaction channels and disagreement at higher outgoing energies to reactions to collectively excited states. Contrary to the fKK multi-step direct calculations, contributions from the higher stages to the DDCs are significant. Different sets of parameters resulted in varying levels of agreement of calculated and experimental data for the considered nuclei.

关键词：反应截面光学势参数预平衡模型参数多步复合相互作用强度实验数据

Microwave sintered porous CoCrfeNiMo high entropy alloy as an efficient electrocatalyst for alkaline oxygen evolution reaction

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Journal of Materials Science & Technology 2021年第20期79卷 171-177页

作者： J.Tang J.L.Xu Z.G.Ye X.b.Li J.M.Luo School of Materials Science and Engineering Nanchang Hangkong UniversityNanchang330063China

Developing efficient,stable and economical electrocatalyst for oxygen evolution reaction(OER)is a significant pathway to produce clean energy from water ***,the promising and highly efficient porous CoCrfeNiMo high entropy alloys(HEAs)were prepared by microwave sintering using Mg space *** to unique properties of high entropy alloys and abundant active surface area,the porous CoCrfeNiMo-20 Mg exhibits excellent catalytic performance and prominent electrochemical stability with a low overpotential of 220 mV to reach current density of 10 mA cm^(-2),a small Tafel slope of 59.0 mV dec^(-1) and long-term durability for 24 h in 1.0 M *** results of microstructure and element states indicate that crystal defects,porous structure and villous hydroxides are the reasons for high OER performance of the *** work not only provides a new way to prepare electrocatalysts,but also proves the important application of high entropy alloys in functional materials.

关键词： CoCrfeNiMo High entropy alloys Electrocatalysts Oxygen evolution reaction Microwave sintering Mg space holder

Microstructure and mechanical properties of aluminium metal matrix composites with addition of.b.mboo leaf ash by stir casting method

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Transactions of Nonferrous Metals Society of China 2017年第12期27卷 2555-2572页

作者： b.Praveen KUMAR Anil Kumar bIRRU Department of Mechanical Engineering National Institute of Technology Manipur 795004 India

Al-4.5%Cu alloy was used as a matrix at2%,4%and6%of.b.mboo leaf ash(bLA)which was extruded from agro waste and was used as *** composite which was f.b.icated by stir casting method possessed superior properties due to an effective bonding between matrix and reinforcement *** f.b.icated composite specimens were subjected to various tests to determine the mechanical properties such as density,porosity,hardness and tensile *** results were compared with basic matrix ***,the OM,SEM with EDAX and XRD analyses were carried out to analyze the dispersion of the reinforced particles in the selected matrix *** was observed that the homogeneous distribution of.b.A particles in composites was intragranular in ***,it was also observed that bLA particles were well bonded with matrix alloy with clear *** was also found that the density decreased with increase in mass fraction of.b.A particles and porosity increased with increase in mass fraction of.b.A *** hardness and tensile strength were increased up to4%of.b.A in the composite,with a further increase in bLA content the hardness and tensile strength decreased.

关键词： Al-4.5Cu alloy stir casting composites bamboo leaf ash density porosity

Structural and plasma characterization of the power effect on the chromium thin film deposited by DC magnetron sputtering

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Optoelectronics Letters 2020年第5期16卷 369-372页

作者： S.Alsheikh Salo b.Abdallah M.Akel M.Kakhia S.Alsheikh Salo B.AbdallahM.AkelM.Kakhia Department of PhysicsAtomic Energy CommissionDamascus P.O.Box 6091Syria1

The chromium(Cr)films on silicon Si(100)substrate are prepared using DC magnetron sputtering technique at an argon gas pressure of 3 Torr for different applied powers(40—140 W).The chemical composition,the thicknesses and the structural characterization of the deposited Cr films are studied and analyzed using energy dispersive X-ray spectroscopy(EDX),scanning electron microscopy(SEM),and X-ray diffraction(XRD),***,the generated plasma parameters,including floating potential,plasma potential,electron density,ion density and electron temperature,have been measured,and the automated Langmuir probe is used for the Cr films *** ion and metal fluxes are also *** results show that the Cr film thickness enhances with the higher applied *** Cr deposited films properties are characterized and correlated with the measured plasma parameters.

关键词： deposited chromium film

Large deformation and wrinkling analyses of.b.modular structures and membranes based on a peridynamic computational framework

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Acta Mechanica Sinica 2019年第6期35卷 1226-1240页

作者： H.Li Y.G.Zheng Y.X.Zhang H.f.Ye H.W.Zhang Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of ChinaChengdu 610200China International Research Center for Computational Mechanics State Key Laboratory of Structural Analysis for Industrial EquipmentDepartment of Engineering MechanicsFaculty of Vehicle Engineering and MechanicsDalian University of TechnologyDalian 116024China

In this paper,the quasi-static large deformation,wrinkling and fracture behaviors of.b.modular structures and membranes are studied with an implicit bond-based peridynamic computational ***,the constant and tangential stiffness matrices of the implicit peridynamic formulations for the nonlinear problems are derived,*** former is con structed from the linearization of the bond strain on the basis of the geometric approximation while the latter is established according to the linearization of the pairwise force by using first-order Taylor’s ***,a bimodular material model in peridynamics is developed,in which the tensile or compressive behavior of the material at each point is conveniently described by the tensile or compressive states of the bonds in its ***,the bimodular material model is extended to deal with the wrinkling and fracture problems of membranes by setting the compressive micro-modulus to be *** addition,the incremental-iterative algorithm is adopted to obtain the convergent solutions of the nonlinear ***,several representative numerical examples are presented and the results demonstrate the accuracy and efficiency of the proposed method for the large deformation,wrinkling and fracture analyses of.b.modular structures and membranes.

关键词： bimodular structures Wrinkling membranes fracture problems Peridynamics Implicit numerical algorithm