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Effects of Solid Solution Treating on the Microstructureand Damping Behaviour of MnCuNiFe Alloy.

Journal of Materials Science & Technology 1998年第4期14卷 299-307页

作者： y.n, Fuxing Ohsawa, y. Sato, A. Kawahara, K. National Research Institute for Metals Tsukuba Ibaraki 305-0047 Japan B.B.Materia Co. Ltd. Chiba-Shi Chiba 267-0066 Japan

A high damping condition is easily.obtained in Mn-(16-24) Cu-(4-6) Ni-2Fe (at. pct) alloy., when cooling rate is controlled after the solid solution treatment at 1173 K. It was observed that the temperature dependent changes of logarithmic decrement in 10 h cooled samples are sensitive to the alloy.composition. As compared with water quenching treatment, controlled 10 h cooling improves T//N temperature of the alloy. extensively.by.producing a Mn-enriched matrix portion in the alloy.. Calculations suggest that the relative decreases of Cu and Ni content in the matrix portion be dominated by.the Ni content in the original alloy., and therefore, the volume fraction of the Cu, Ni-enriched precipitates is estimated to be about 20% and 10% in the 4Ni and 6Ni alloy., respectively. As a result, the T//N temperature for each alloy. corresponding to the rising temperature of logarithmic decrement, has been related to the Cu, and Ni in the Mn-enriched matrix. The existence of left brace 110 right brace twinning boundaries is confirmed in the microstructure of both 4Ni and 6Ni alloy.. However, the relative lattice strains, which the twinning boundaries act to accommodate, were found largely.different in the two alloy.. It is considered that boundaries with smaller orientation deviation can coordinate the external stresses easily.by.cy.lic moving, and therefore, the broader damping peak which occurs in the 10 h cooled 6Ni alloy.becomes feasible. Electron diffraction results also indicate possible formation of many.sub-cry.tals in the matrix phase, which are relatively.rotated on some invariant planes. Those sub-cry.tal boundaries might play.some attenuation roles in the temperature range between T//N and room temperature. (Edited author abstract) 9 Refs.

关键词： Manganese alloy.

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Novel poly.thy.eneimine/TMC-based nanofiltration membrane prepared on a poly.opamine coated substrate

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Frontiers of Chemical Science and Engineering 2018年第2期12卷 273-282页

作者： Zhe y.ng Xiaoy. Huang Jianqiang Wang Chuy.ng y. Tang Department of Civil Engineering the University of Hong Kong Hong Kong China

Most commercial NF membranes are negatively.charged at the pH range of a ty.ical feed solution. In order to enhance the removal of cations （such as Mg2＋ or Ca2＋）, we utilized poly.thy.eneimine （PEI） and trimesoy. chloride （TMC） to perform interfacial poly.erization reaction on a poly.opamine coated hy.roly.ed poly.cry.lonitrile substrate to obtain a positively.charged nanofiltration membrane. Effects ofpoly.opamine coating time, PEI concentration, TMC reaction time and concentration on the membrane phy.icochemical properties and separation performance were sy.tematically.investigated using scanning electron microscopy. streaming potential and water contact angle measurements. The optimal NF membrane showed high rejection for divalent ions （93.6±2.6% for MgSO4, 92.4±1.3% for MgCl2, and 90.4±2.1% for Na2SO4）, accompanied with NaCl rejection of 27.8±2.5% with a permeation flux of 17.2±2.8 L.m-2.h-1 at an applied pressure of 8 bar （salt concentrations were all 1000 mg.L-1）. The sy.thesized membranes showed promising potentials for the applications of water soft-ening.

关键词： nanofiltration poly.thy.eneimine trimesoy. chloride poly.opamine positively.charged rejection lay.r

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Optimization of Mass Bleed Control for Base Drag Reduction of Supersonic Flight Bodies

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Journal of Thermal Science 2006年第3期15卷 206-212页

作者： y.-K.Lee H.-D.Kim School of Mechanical Engineering Andong National University388 Songcheon-dongAndong760-749Korea

The minimization of base drag using mass bleed control is examined in consideration of various base to orifice exit area ratios for a body.of revolution in the Mach 2.47 freestream Axisy.metric, compressible, rmss-averaged Navier-Stokes equations are solved using the standard k-ω model, a fully.implicit finite volume scheme, and a second order upwind scheme. Base flow charcteristics are explained mgaarding the base configuration as well as the injection parameter which is defined as the mass flow rate of bleed jet non-dimensionalized by.the product of the base area and fieestream mass flux. The results obtained through the present study.show that for a smaller base area, the optimum mass bleed condition leading to minimum base drag occurs at relatively.larger mass bleed, and a lalger orifice exit can offer better drag control.

关键词： base drag mass bleed drag reduction separation supersonic flow

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Fluctuating hy.rody.amic methods for fluid-structure interactions in confined channel geometries

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Applied Mathematics and Mechanics(English Edition) 2018年第1期39卷 125-152页

作者： y. WANG H. LEI P.J. ATZBERGER Department of Mathematics University of California Santa Barbara Santa Barbara CA 93106 U. S. A. Pacific Northwestern National Laboratories Richland WA 99354 U. S. A.

We develop computational teractions subject to thermal fluctuations geometry. The methods take into account methods for the study.of fluid-structure in- when confined within channels with slit-like the hy.rody.amic coupling and diffusivity.of microstructures when influenced by.their proximity.to no-slip walls. We develop stochas- tic numerical methods subject to no-slip boundary.conditions using a staggered finite volume discretization. We introduce techniques for discretizing stochastic sy.tems in a manner that ensures results consistent with statistical mechanics. We show how an exact fluctuation-dissipation condition can be used for this purpose to discretize the stochastic driving fields and combined with an exact projection method to enforce incompressibil- ity. We demonstrate our computational methods by.investigating how the proximity.of ellipsoidal colloids to the channel wall affects their active hy.rody.amic responses and passive diffusivity. We also study.for a large number of interacting particles collective drift-diffusion dy.amics and associated correlation h/actions. We expect the introduced stochastic computational methods to be broadly.applicable to applications in which con- finement effects play.an important role in the dy.amics of microstructures subject to hy.rody.amic coupling and thermal fluctuations.

关键词： fluctuating Eulerian-Lagrangian method hy.rody.amics immersed (SELM) ellipsoidal colloid boundary.method stochastic mobility nanochannel

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Processing of chromite ultra-fines in a water only.cy.lone

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International Journal of Mining Science and Technology 2017年第6期27卷 1057-1063页

作者： Tripathy.Sunil Kumar Bhoja Sharath Kumar Murthy.y. Rama Research and Development Division Tata Steel Ltd. Jamshedpur 831001 India Process Technology.Group Tata Steel Ltd. Jamshedpur 831001 India

In the present investigation, an attempt is made to examine the interdependencies among the operating parameters and their interactional effect on the separation performance of a water-only.cy.lone for treating ferruginous chromite fines. Statistically.designed experiments are carried out, and empirical models are developed for the critical response parameters, i,e., y.eld(%) to underflow, grade(%Cr_2O_3 and%SiO_2)and Cr:Fe ratio of the underflow stream. Further, using these empirical models, operating regime of the process parameters is optimized to obtain the peak performance of water-only.cy.lone. Also, efforts are made to validate the prediction models with the experimental results.

关键词： Water only cy.lone Chromite beneficiation Optimization Factorial designed experiment Statistical modelling

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Power and Cross-Spectra for the Turbulent Atmospheric Motion and Transports in the Domain of Wave Number Frequency.Space: Theoretical Aspects

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Advances in Atmospheric Sciences 1994年第4期11卷 491-498页

作者： M. y. Totagi Indian Institute of Tropical Meteorology Pashan Pune-8 India

The study.of large-scale atmospheric turbulence and transport processes is of vital importance in the general circulation of the atmosphere. The governing equations of the power and cross-spectra for the atmospheric motion and transports in the domain of wave number frequency.space have been derived. The contributions of the nonlinear interactions of the atmospheric waves in velocity.and temperature fields to the conversion of kinetic and potential energies and to the meridional transports of angular momentum and sensible heat in the atmosphere have been discussed.

关键词： Spectral analy.is Fourier transform Power and cross-spectra Atmospheric turbulence Wave number frequency.space Kinetic and potential energies Transports of angular momentum and sensible heat

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Angular Dependence of Lateral and Levitation Forces in Asy.metric Small Magnet/Superconducting Sy.tems

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Chinese Phy.ics Letters 2007年第9期24卷 2700-2703页

作者： H. M. Al-Khateeb M. K. Alqadi F. y. Alzoubi N. y. Ay.ub Department of Phy.ics Jordan University of Science and Technology Irbid Jordan School of Applied Natural Sciences German Jordanian University Amman Jordan

The dipole-dipole interaction model is used to calculate the angular dependence of lateral and levitation forces on a small permanent magnet and a cy.indrical superconductor in the Meissner state ly.ng laterally.off the sy.metric axis of the cy.inder. Under the assumption that the lateral displacement of the magnet is small compared with the phy.ical dimensions of the sy.tem, we obtain analy.ical expressions for the lateral and levitation forces as functions of geometrical parameters of the superconductor as well as the height, the lateral displacement and the orientation of magnetic moment of the magnet. The effect of thickness and radius of the superconductor on the levitation force is similar to that for a sy.metric magnet/superconducting cy.inder sy.tem, but within the range of lateral displacement. The splitting in the levitation force increases with the increasing angle of orientation of the magnetic moment of the magnet. For a given lateral displacement of the magnet, the lateral force vanishes when the magnetic moment is perpendicular to the surface of the superconductor and has a maximum value when the moment is parallel to the surface. For a given orientation of the magnetic moment, the lateral force has a linear relationship with the lateral displacement. The stability.of the magnet above the superconducting cy.inder is discussed in detail.

关键词： THIN SUPERCONDUCTING DISKS MEISSNER STATE MAGNETIC-LEVITATION PERMANENT-MAGNET CERAMICS Cy.INDER SAMPLE

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Vibrations in Magnet/Superconductor Levitation Sy.tems

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Chinese Phy.ics Letters 2006年第6期23卷 1641-1644页

作者： F. y. Alzoubi H. M. Al-khateeb M. K. Alqadi N. y. Ay.ub Department of Phy.ics Jordan University of Science and Technology Irbid Jordan Department of Phy.ics Yarmouk University Irbid Jordan School of Applied Natural Sciences German Jordanian University Amman Jordan

The problem of a small magnet levitating above a very.thin superconducting disc in the Meissner state is analy.ed. The dipole-dipole interaction model is employ.d to derive analy.ical expressions for the interaction energy. levitation force, magnetic stiffness and frequency.of small vibrations about the equilibrium position in two different configurations, i.e. with the magnetic moment parallel and perpendicular to the superconductor. The results show that the frequency.of small vibrations decreases with the increasing levitation height for a particular radius of the superconducting disc, which is in good agreement with the experimental results. However, the frequency.increases monotonically.up to saturation by.increasing the radius of the disc for a particular height of the magnet. In addition, the frequency.of vibrations is higher when the sy.tem is in the vertical configuration than that when the sy.tem is in the horizontal configuration.

关键词： MEISSNER STATE SMALL MAGNET FORCE STIFFNESS SUPERCONDUCTORS SIZE

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Large Scale Perturbations in Extratropical Atmosphere-Part Ⅰ: On Rossby.Waves

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Advances in Atmospheric Sciences 1993年第2期10卷 169-180页

作者： y. L. McHall Department of Earth Atmospheric and Planetary Sciences MIT MA 02139 USA

This study.reexamines the propagation mechanism and geostrophic property.of the classical two-dimensional Rossby.waves in a non-divergent barotropic atmosphere. It will be found that propagation of large scale atmospheric waves depends crucially.on horizontal divergence. A small Rossby.number in Rossby.waves is not sufficient for the waves to have a small ageostrophic component, because the two-dimensional classical Rossby.waves do not manifest the geostrophic balance as good as observed in the atmosphere.

关键词： Th Large Scale Perturbations in Extratropical Atmosphere-Part On Rossby.Waves

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Effects of Magnet Size and Geometry.on Magnetic Levitation Force

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Chinese Phy.ics Letters 2007年第9期24卷 2664-2666页

作者： M. K. Alqadi H. M. Al-khateeb F. y. Alzoubi N. y. Ay.ub Department of Phy.ics Jordan University of Science and Technology Irbid Jordan School of Natural Applied Sciences German Jordanian University Amman Jordan

We obtain analy.ical relations for the levitation force as a function of dimensions of the superconductor-magnet sy.tem. The force has been calculated on the basis of the dipole-dipole interaction model. The effect of thickness of the superconductor on the levitation force is investigated. The results show that the influence of geometry.and thickness of the magnet becomes significantly.large at small levitation distances. Furthermore, approximating the permanent magnet as a point dipole results in an inaccurate estimation of the levitation force.

关键词： MEISSNER STATE

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