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Effect of forced-air cooling on the microstructure and age-hardening response of extruded Mg-gd-Y-zn-zr alloy full with LPSO lamella

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Journal of Materials Science & Technology 2021年第14期73卷 66-75页

作者： S.z.Wu T.Nakata g.z.Tang c.Xu X.J.Wang X.W.Li X.g.Qiao M.Y.zheng L.geng S.Kamado g.H.Fan School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China Research center for Advanced Magnesium Technology Nagaoka University of TechnologyNagaoka 940-2188Japan School of Material Science and Engineering Harbin University of Science and TechnologyHarbin 150040China Key Laboratory for Light-weight Materials Nanjing Tech UniversityNanjing 211816China

The homogenized Mg-8.2 gd-3.8 Y-1.0 zn-0.4 zr(wt.%)alloy full of plate-shaped long period stacking ordered(LPSO)phases was hot extruded in the atmosphere and cooled by the forced-air,then the effect of forced-air cooling on the microstructure and age-hardening response of the alloy was investigated in this *** results show that in comparison with the extruded sample cooling in the atmosphere,the forced-air cooling restricts dynamic recrystallization(DRX)and brings about finer dynamic recrystallized(DRXed)grain size,stronger basal texture and higher dislocation ***,the forced-air cooling promotes the dynamic precipitation in the DRXed regions and facilitates formation of plate-shaped LPSO phases andγ’phases with smaller interspacing in the unrecrystallized(un DRXed)regions,then slightly restricts the precipitation ofβphases during *** peak-ageing treatment,the extruded sample with forced-air cooling shows superior tensile properties with a tensile yield strength of 439 MPa,an ultimate tensile strength of 493 MPa,and elongation to failure of 18.6%.

关键词： Mg-RE alloy LPSO phase Dynamic recrystallization Precipitation Mechanical properties

Development and characterization of a microfluidic glucose sensing system based on an enzymatic microreactor and chemiluminescence detection

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Science china chemistry 2012年第4期55卷 515-523页

作者： MOON B.-u. de VRIES M.g. WESTERINK B.H.c. VERPOORTE E. Biomonitoring and Sensoring Department of Pharmacy University of Groningen Antonius Deusinglaan 1 9713AV Groningen The Netherlands Pharmaceutical Analysis Department of Pharmacy University of Groningen Antonius Deusinglaan 1 9713AV Groningen The Netherlands Brains-on-Line PO Box 4030 9713AV Groningen The Netherlands

chemiluminescence detection was developed as an alternative to amperometric detection for glucose analysis in a portable, microfluidicsbased continuous glucose monitoring system. Amperometric detection allows easy determination of hydrogen peroxide, a product of the glucose oxidasecatalyzed reaction of glucose with oxygen, by oxidation at a microelectrode. However, （micro）electrodes in direct contact with physiological sample are subject to electrode fouling, which leads to signal drift, decreased reproducibility and shortened detector lifetimes. Moreover, there are a few species present in the body （e.g. ascorbic acid, uric acid） which can undergo oxidation at the same applied potential as hydrogen peroxide. These species can thus inter- fere with the glucose measurement, reducing detection specificity. The rationale for exploring chemiluminescence as opposed to amperometric detection is thus to attempt to improve the lifetime and reproducibility of glucose analysis for monitoring purposes, while reducing interference caused by other chemicals in the body. The study reported here represents a first step in this direction, namely the realization of a microfluidic device with integrated silicon photodiode for chemiluminescence detection of glucose. This microflow device uses a chaotic mixing approach to perform enzymatic conversion of glucose, followed by reaction of the hydrogen peroxide produced with luminol to produce light at 425 nm. The chemil reaction is catalyzed by horseradish peroxidase in the presence of iodophenol. The performance of the fabricated chip was characterized to establish optimal reaction conditions with respect to sample and reagent flow rates, pH, and concentrations. A linear calibra- tion curve was obtained for current response as a function of glucose concentration in the clinically relevant range between 2 and 10 mM, with a sensitivity of 39 pA/mM （R = 0.9963, one device, n = 3） and a limit of detection of 230 ktM （S/N - 3）.

关键词： microfluidic chip – glucose sensing system – enzymatic microreactor – chemiluminescence – chaotic mixing

Linear Analysis of Obliquely Propagating Longitudinal Waves in Partially Spin Polarized Degenerate Magnetized Plasma

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communications in Theoretical Physics 2017年第12期67卷 791-797页

作者： z.Iqbal g.Murtaza A.Hussain Salam chair Department of Physics G.C. University Lahore Department of Physics Mirpur University of Science and Technology

Linear analysis of low frequency obliquely propagating electrostatic waves in a partially spin polarized degenerate magnetized plasma is presented. using Fourier analysis, a general linear dispersion relation is derived for low frequency electrostatic lower hybrid(LH) wave, ion acoustic(IA) wave and ion cyclotron(Ic) wave in the presence of electron spin polarization. It is found that the electron spin polarization gives birth to a new spin-dependent wave(spin electron acoustic wave) in the spectrum of these waves. Further, the electron spin polarization also causes drastic shifts in the frequency spectrum of these waves. These effects would have a strong bearing on wave phenomena in degenerate astrophysical plasmas.

关键词： spin polarization longitudinal waves degenerate plasma

DAMPINg BEHAVIOR OF uLTRAFINE-gRAINED PuRE ALuMINuM L2 AND THE DAMPINg MEcHANISM

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Acta Metallurgica Sinica(English Letters) 2006年第3期19卷 223-227页

作者： z.M. zhang c.J. Xu J.c. Wang H.z. Liu School of Materials Science ＆ Engineering Xi＇an University of Technology Xi＇an 710048 Ghina State Key Laboratory of Solidification Processing Northwestern Polytechnical University Xi＇an 710072 Ghina

ultrafine-grained pure aluminum L2 with a mean grain size of 1.01μm was produced by equal channel angular pressing （EcAP） and annealing at 150℃ for 2h. Damping behavior of the alloy was measured using a dynamic mechanical thermal analyzer. The alloy had an excellent damping capacity Q^-1 with the ambient value being 9.8×10^-3 at 1.0Hz when the strain amplitude was 2.0×10^-5. The damping behavior of the alloy showed a non-linear damping variation tendency, that is, with an increase in temperature and a decrease of frequency, the damping capacity of the alloy increased. The damping capacity increased with the strain amplitude when the strain amplitude was less than 4.6×10^-5. When the strain amplitude was higher than 4.6×10^-5, the damping capacity became a constant and independent of strain amplitude. The high damping capacity was attributed to dislocation unpinning and a drag of dislocation on pinning points.

关键词： EcAP ultrafine grain damping capacity aluminum alloy

Shear band evolution and mechanical behavior of cold-rolled zr-based amorphous alloy sheets:An in-situ study

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Journal of Materials Science & Technology 2024年第14期181卷 115-127页

作者： c.Y.zhang z.W.zhu S.T.Li Y.Y.Wang z.K.Li H.Li g.Yuan H.F.zhang School of Metallurgy Northeastern UniversityShenyang 110819China Shi-changxu Innovation center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China The State Key Laboratory of Rolling and Automation(RAL) Northeastern UniversityShenyang 110819China

cold rolling process can regulate the microstructure and mechanical properties of amorphous alloys,but it is still a challenging task to reveal their microscopic ***,we designed an in-situ SEM observation device for the cold rolling process of amorphous alloy,and visually observed the formation and evolution of shear bands during single-pass and multi-pass rolling process of the zr_(55)cu_(30)Al_(10)Ni_(5)amorphous alloy *** is found that the evolution process of shear bands in the rolling process of amorphous alloy shows heritability,which is mainly reflected in two aspects:one is that the shear band formation pattern in the single-pass rolling process is more inclined to inherit the previous shear band formation pattern;the other is that the shear deformation is more likely to occur in the pre-existing shear bands in the multi-pass rolling *** rule can be used to guide the controlled genera-tion of shear bands in amorphous ***,we emphasized the importance of pre-existing shear band orientations and systematically investigated the mechanical behavior of the amorphous alloys with pre-existing shear bands by in-situ SEM *** is found that the mechanical properties of the as-rolled amorphous alloys are determined by the competition between the work-softening of the pre-existing shear band itself and the work-hardening caused by the blocking effect of the pre-existing shear bands on the shear *** on this,we enhance the tensile fracture strength and the tensile ductility of the amorphous alloy by adjusting the orientation of the pre-existing shear bands parallel to the tensile stress axis so that the pre-existing shear bands prevent the linear propagation and destruction of the new shear bands.

关键词： Amorphous alloy cold rolling Shear band Mechanical behavior In-situ study Plasticity

Synthesis of self-assembled nanorod vanadium oxide bundles by sonochemical treatment

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Journal of Natural gas chemistry 2009年第3期18卷 312-318页

作者： Y.H.Taufiq-Yap Y.c.Wong z.zainal M.z.Hussein centre of Excellence for catalysis Science and Technology Faculty of ScienceUniversiti Putra Malaysia Department of chemistry Faculty of ScienceUniversiti Putra Malaysia

Self-assembled nanorod of vanadium oxide bundles were synthesized by treating bulk V2O5 with high intensity sonochemical technique. The synthesized materials were characterized by X-ray diffraction （XRD）, scanning electron microscope （SEM）, transmission electron microscope （TEM） and temperature-programmed reduction （TPR） in H2. catalytic behaviour of the materials over anaerobic n-butane oxidation was studied through temperature-programmed reaction （TPRn）. catalytic evaluation of the sonochemical treated V2O5 products was also studied on microreactor. XRD patterns of all the vanadium samples were perfectly indexed to V2O5. The morphologies of the nanorod vanadium oxides as shown in SEM and TEM depended on the duration of the ultrasound irradiation. Prolonging the ultrasound irradiation duration resulted in materials with uniform, well defined shapes and surface structures and smaller size of nanorod vanadium oxide bundles. H2-TPR profiles showed that larger amount of oxygen species were removed from the nanorod V2O5 compared to the bulk. Furthermore, the nanorod vanadium oxide bundles, which were produced after 90, 120 and 180 min of sonochemical treatment, showed an additional reduction peak at lower temperature （-850 K）, suggesting the presence of some highly active oxygen species. TPRn in n-butane/He over these materials showed that the nanorod V2O5 with highly active oxygen species showed markedly higher activity than the bulk material, which was further proven by catalytic oxidation of n-butane.

关键词： nanorod vanadium oxide sonochemical treatment butane oxidation

charge self-trapping in two strand biomolecules:Adiabatic polaron approach

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chinese Physics B 2023年第1期32卷 253-263页

作者： D chevizovich S zdravković A V chizhov z Ivić university of Belgrade Vinča Institute of Nuclear SciencesP.O.Box 522Belgrade 11001Serbia Joint Institute for Nuclear Research Laboratory for Radiation BiologyDubna 141980Russia Dubna State university Dubna 141980Russia Department of Physics University of CreteP.O.Box 2208Heraklion 71003Greece National university of Science and Technology MISiS Leninsky prosp.4Moscow 119049Russia

We investigate the properties of the excess charge(electron, hole) introduced into a two-strand biomolecule. We consider the possibility that the stable soliton excitation can be formed due to interaction of excess charge with the phonon subsystem. The influence of overlap of the molecular orbitals between adjacent structure elements of the macromolecular chain on the soliton properties is discussed. Special attention is paid to the influence of the overlapping of the molecular orbitals between structure elements placed on the different chains. using the literature values of the basic energy parameters of the two-chain biomolecular structures, possible types of soliton solutions are discussed.

关键词： charge self-trapping adiabatic polaron soliton two-stranded biomolecules

Strategies for baryon resonance analysis

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chinese Physics c 2009年第12期33卷 1127-1131页

作者： M. Dring c. Hanhart 黄飞 S. Krewald u.-g. Meiβner Institut fr Kernphysik and Jlich center for Hadron Physics Forschungszentrum Jlich D-52425 Jlich Germany Institute for Advanced Simulation Forschungszentrum Jlich D-52425 Jlich Germany Department of Physics and Astronomy University of Georgia Athens Georgia 30602 USA Helmholtz-Institut fr Strahlen-und Kernphysik (Theorie) and Bethe center for Theoretical Physics Universitt Bonn Nuβallee 14-16 D-53115 Bonn Germany

The analytic properties theoretical investigations of baryon of scattering amplitudes provide a meeting point for experimental and resonances. Pole positions and residues allow for a parameterization of resonances in a well-defined way which relates different reactions. The recent progress made within the Jiilich model is summarized.

关键词： pion-nucleon scattering meson exchange model analytic structure of the scattering amplitude

Non-existence of Shilnikov chaos in continuous-time systems

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Applied Mathematics and Mechanics(English Edition) 2012年第3期33卷 371-374页

作者： z.ELHADJ J.c.SPROTT Department of Mathematics University of T'ebessaT'ebessa 12002Algeria Department of Physics University of Wisconsin-MadisonWI 53706USA

In this paper, a non-existence condition for homoclinic and heteroclinic orbits in n-dimensional, continuous-time, and smooth systems is obtained, Based on this result and an elementary example, it can be conjectured that there is a fourth kind of chaos in polynomial ordinary differential equation （ODE） systems characterized by the nonexistence of homoclinic and heteroclinic orbits.

关键词： homoclinic chaos heteroclinic chaos non-existence of Shilnikov chaos