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Giant magnetoresistance Effect of [bcc-Fe(m)/Cu](m=Co,Ni) multilayers

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Journal of materials Science & Technology 2000年第2期16卷 186-190页

作者： m.matsui, m.Doi and N.Shimizu (Department of Crystalline materials Science and Engineering, Nagoya University, Chikusa-ku, Nagoya 464-8603, Japan Department of Crystalline materials Science and Engineering Nagoya University Chikusa-ku Nagoya 464-8603 Japan

GmR effect of multilayers of bcc-Fe(m)(m=Co, Ni) alloy and Cu layers has been investigated. The maximum mR ratio is found at 1.1 nm Fe(Co) and 1.3～1.4 nm Cu layer thickness in [Fe(Co)/CuJ, and at 1.6 nm Fe(Ni) and 1.4 nm Cu layer thickness in [Fe(Ni)/Cu]. Under the optimum annealing condition, the mR ratio increases up to 50% and 38% for Fe(Co) and Fe(Ni) systems, respectively. The origin of the increase of GmR is discussed, taking the progress of preferred orientation of Fe(Co)[100] or Fe(Ni)[100] by anneahng into account.

关键词： Giant magnetoresistance Effect of m=Co,Ni multilayers Cu bcc-Fe

Finite deformation swelling of a temperature-sensitive hydrogel cylinder under combined extension-torsion

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Applied mathematics and mechanics(English Edition) 2020年第3期41卷 409-424页

作者： m.SHOJAEIFARD m.BAGHANI College of Engineering University of TehranTehran ***Iran

The swelling behavior of a temperature-sensitive poly-N-isopropylacrylamide(PNIPAm) hydrogel circular cylinder is studied subjected to combined extension-torsion and varied temperature. In this regard, a semi-analytical solution is proposed for general combined loading. A finite element(FE) analysis is conducted, subjecting a hydrogel cylinder to the combined extension-torsion and the varied temperature to evaluate the validity and accuracy of the solution. A user-defined UHYPER subroutine is developed and verified under free and constrained swelling conditions. The FE results illustrate excellent agreement with the semi-analytical solution. Due to the complexity of the problem, some compositions and applied loading factors are analyzed. It is revealed that for larger cross-linked density and larger ending temperature, the cylinder yields higher stresses and smaller radial swelling deformation. Besides, the radial and hoop stresses increase by applying larger twist and axial stretch. The hoop stresses intersect at approximately R/Rout = 0.58, where the hoop stress vanishes. Besides, the axial force has direct and inverse relationships with the axial stretch and the twist, respectively. However, the resultant torsional moment behavior is complex, and the position of the maximum point varies significantly by altering the axial stretch and the twist.

关键词： extension-torsion of the circular cylinder temperature variation finite element(FE)analysis temperature-sensitive poly-N-isopropylacrylamide(PNIPAm)hydrogel semi-analytical solution

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

Study of magnetic and optical properties of Zn1-xTmxTe(Tm = mn,Fe,Co,Ni) diluted magnetic semiconductors：First principle approach

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Chinese Physics B 2017年第2期26卷 452-460页

作者： Q mahmood m Hassan m A Faridi Department of Physics University of the Punjab Quaid-e-Azam Campus-54590 Lahore Pakistan Centre for High Energy Physics University of the Punjab Lahore Pakistan

We present structural,magnetic and optical characteristics of Zn_（1-x）Tm_xTe（Tm = mn,Fe,Co,Ni and x = 6.25%）,calculated through Wien2 k code,by using full potential linearized augmented plane wave（FP-LAPW） *** optimization of the crystal structures have been done to compare the ferromagnetic（Fm） and antiferromagnetic（AFm） ground state energies,to elucidate the ferromagnetic phase stability,which further has been verified through the formation and cohesive ***,the estimated Curie temperatures T_c have demonstrated above room temperature ferromagnetism（RTFm） in Zn_（1-x）Tm_xTe（Tm =mn,Fe,Co,Ni and x= 6.25%）.The calculated electronic properties have depicted that mn- and Co-doped ZnTe behave as ferromagnetic semiconductors,while half-metallic ferromagnetic behaviors are observed in Fe- and Ni-doped *** presence of ferromagnetism is also demonstrated to be due to both the p-d and s-d hybridizations between the host lattice cations and Tm *** calculated band gaps and static real dielectric constants have been observed to vary according to Penn＇s *** evaluated band gaps lie in near visible and ultraviolet regions,which make these materials suitable for various important device applications in optoelectronic and spintronic.

关键词： magnetic semiconductors density functional theory optical and dielectric properties electron density of states and band structure of crystalline solids

Application of Nanocrystalline LaNi_5-type Hydrogen Absorbing Alloys in Ni-mH_x Batteries

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Journal of Rare Earths 2004年第5期22卷 596-599页

作者： Jurczyk m Nowak m Institute of materials Science and Engineering Poznan University of Technology 60-965 Poznan PolandInstitute of Materials Science and Engineering Poznan University of Technology 60-965 Poznan Poland

The structure and electrochemical properties of nanocrystalline LaNi_5-type alloys were studied. These materials were prepared by mechanical alloying (mA) followed by annealing. The properties of hydrogen host materials can be modified substantially by alloying to obtain the desired storage characteristics. It was found that the partial substitution of Ni by Al or mn in LaNi_(5-x)m_x alloy leads to an increase in discharge capacity. The alloying elements such as Al, mn and Co greatly improved the cycle life of LaNi_5 material. For example, in the nanocrystalline LaNi_(3.75)mn_(0.75)Al_(0.25)Co_(0.25) powder, discharge capacity up to 258 mAh·g^(-1) was measured (at 40 mA·g^(-1) discharge current). Furthermore, the effect of the graphite coating on the structure of some nanocrystalline alloys and the electrodes characteristics were investigated. The mechanical coating with graphite effectively reduced the degradation rate of the studied electrode materials. The combination of a nanocrystalline LaNi_5-type hydride electrodes and a nickel positive electrode to form a Ni-mH battery, was successful.

关键词： hydrogen absorbing materials electrode materials nanocrystalline materials Ni-mH_x batteries rare earths

The Properties of the Space-Charge and Net Current Density in magnetized Plasmas

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Plasma Science and Technology 2013年第12期15卷 1169-1173页

作者： m.m.HATAmI Physics Department of K N Toosi University of Technology

A hydrodynamic model is used to investigate the properties of positive space-charge and net current density in the sheath region of magnetized, collisional plasmas with warm positive ions. It is shown that an increase in the ion-neutral collision frequency, as well as the magnitude of the external magnetic field, leads to an increase in the net current density across the sheath region. The results also show that the accumulation of positive ions in the sheath region increases by increasing the ion-neutral collision frequency and the magnitude of the magnetic field. In addition, it is seen that an increase in the positive ion temperatures causes a decrease in the accumulation of positive ions and the net current density in the sheath region.

关键词： hydrodynamic model magnetized plasma sheath sheath formation criterion

Spectroscopic Studies of the Laser Produced Lead Plasma

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Plasma Science and Technology 2011年第2期13卷 129-134页

作者： m.HANIF m.SALIK m.A.BAIG Atomic & molecular Physics Laboratory Department of Physics Quaid-Ⅰ-Azam University mCS National University of Sciences & Technology

Spectroscopic emission of lead plasma, generated by the fundamental （1064 nm） and second harmonics （532 nm） of a Q-switched pulsed Nd： YAG laser, is studied. The spectral lines of neutral atoms and singly ionized lead ions were shown predominantly. The profiles of neutral lead lines observed were used to extract the excitation temperature using Boltzmann plots, whereas electron number density was determined from the profile of Stark broadened line. The variations of excitation temperature and electron number density as a function of laser energy were studied.

关键词： lead laser ablation optical emission spectroscopy plasma temperature and electron density

Oblique collisional effects of dust acoustic waves in unmagnetized dusty plasma

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Chinese Physics B 2020年第6期29卷 304-313页

作者： m S Alam m R Talukder Department of mathematics Chittagong University of Engineering and TechnologyChittagong-4349Bangladesh Plasma Science and Technology Laboratory Department of Electrical and Electronic EngineeringUniversity of RajshahiRajshahi-6205Bangladesh

Effects of oblique collisions of the dust acoustic(DA)waves in dusty plasma are studied by considering unmagnetized fully ionized *** plasma consists of inertial warm negatively charged massive dusts,positively charged dusts,superthermal kappa distributed electrons,and isothermal *** extended Poincaré–Lighthill–Kuo(e PLK)method is employed for the drivation of two-sided Korteweg–de Vries(KdV)equations(KdVEs).The Kd V soliton solutions are derived by using the hyperbolic secant *** effects of superthermality index of electrons,temperature ratio of isothermal ion to electron,and the density ratio of isothermal ions to negatively charged massive dusts on nonlinear coefficients are *** effects of oblique collision on amplitude,phase shift,and potential profile of right traveling solitons of DA waves are also *** study reveals that the new nonlinear wave structures are produced in the colliding region due to head-on collision of the two counter propagating DA *** nonlinearity is found to decrease with the increasing density ratio of ion to negative dust in the critical *** phase shifts decrease(increase)with increasing the temperature ratio of ion to electron(κe).The hump(compressive,κeκec)solitons are produced depending on the angle(θ)of oblique collision between the two waves.

关键词： ion acoustic wave dusty plasma kappa distribution ePLK method hyperbolic secant method

Adsorption properties of Rosmarinus officinalis oil as green corrosion inhibitors on C38 steel in 0.5 m H_2SO_4

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Acta metallurgica Sinica(English Letters) 2010年第1期23卷 13-20页

作者： E.El Ouariachi J.Paolini m.Bouklah A.Elidrissi A.Bouyanzer B.Hammouti J-m.Desjobert J.Costa Laboratoire de Chimie Appliqu'ee et Environnement Facult'e des SciencesUniversit'e Mohamed PremierBP71760000 OujdaMorocco UmR CNRS 6134 Laboratoire de Chimie des Produits NaturelsUniversit'e de CorseFrance

Rosmarinus officinalis essential oil obtained by hydrodistillation was tested as corrosion inhibitor of steel in 0.5 m H2SO4 using weight loss measurements, and electrochemical .polarisation methods. Results obtained indicate that the corrosion rate is reduced and R. officinalis oil adsorbs on the metal surface and then inhibits corrosion process. Its inhibition efficiency increases with oil increasing content to reach 61% at 1 g/L. Polarisation curves indicate that RO acts as a cathodic inhibitor. The inhibition efficiency of naturally oil remains slightly constant with the rise of temperature. Chemical analysis of R. officinalis essential oil was carried out using capillary GC and GC/mS. The oil composition was characterized by high amount of oxygenated monoterpene （77%） with 1,8-cineol （52.1%） as main component. Discussion of adsorption was investigated on the the isotherm adsorption of essential oil on basis of essential oil composition. Finally the steel has been also reported.

关键词： Rosmarinus officinalis oil Adsorption Corrosion Inhibition Steel 1,8-cineol