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Inter-Calibration Between Plasma Instruments Onboard DEMETER

Plasma science and Technology 2008年第5期10卷 539-545页

作者： Maha s.QUAssIM National Research Institute of Astronomy and Geophysics Helwan 11421CairoEgypt

The in-situ measurements of the ionospheric plasma that we use come from two instruments of the scientific payload of the satellite DEMETER; the plasma analyser IAP （Instrument d＇analyse du plasma） and the Langmuir probe IsL （Instrument sonde de Langmuir）. DEMETER is a micro-satellite realized by the CNEs（Centre National d＇Etudes spatiales, france） with a principal objective to seek a possible influence of the seismic activity on the electromagnetic waves in the ionosphere and on the ionospheric plasma. The satellite was placed on June 29, 2004, in a circular and quasi helio-synchronous orbit at -710 km altitude. The experiments function primarily at mid-latitudes （from ＋60° to -60°）. The IAP data were analysed to deduce the ion population （densities of the dominant ions, i.e. generally O^＋, H^＋ and He^＋） therefore the total ion density. The use of data IAP thus requires some precaution to make sure that the electric equilibrium conditions of the satellite, such as the satellite potential （Фsat）, are obtained during the treatment of routine, does not induce an error of measurement. When this potential is negative, the minority light ions H^＋ and He^＋ can be measured in a reliable way when their proportion is above 3% to 5% of that of O^＋. The critical limitation is： under certain conditions, the satellite potential becomes positive and reach a value about -0.5 V so that it becomes impossible to measure H^＋ ions. This is likely to involve a significant error on the composition and the density of the plasma. Therefore we carried out a calibration to estimate the missing density. The IsL experiment （Langmuir probe） provided the collected current/polarized tension characteristics of a cylindrical probe from which both electron density Ne and temperature Te were obtained. In some situations it is necessary to examine the accuracy of the electron density using another technique, for instance the high frequency （Hf） spectrogram, provided by ICE （instrument champ electrique

关键词： plasma analyser satellite plasma observation ion density measuring

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Improving the performance of structure-embedded acoustic lenses via gradient-index local inhomogeneities

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International Journal of smart and Nano Materials 2015年第1期6卷 1-13页

作者： H.Zhu f.semperlotti Department of Aerospace and Mechanical Engineering University of Notre DameNotre DameIndiana 46556USA

We investigate the use of graded inhomogeneities in order to enhance the focusing and collimation performance of structure-embedded acoustic metamaterial *** type of inhomogeneity exploited in this study consists in axial symmetric exponential-like gradients of either material or geometric properties that create gradient-index inclusions able to bend and redirect propagating *** particular,we exploit the concept of gradient index inclusions to achieve focusing and collimation of ultrasonic beams created by embedded drop-channel lenses in both bulk and thin-walled *** the latter,the implementation is possible thanks to geometric exponential tapers known as Acoustic Black Holes(ABH).ABH tapers allow accurate control of the characteristics of the acoustic beam emanating from the lens channel which in the conventional design is severely affected by *** concept of beam control via graded inclusions is numerically illustrated and validated by using a combination of methodologies including geometric acoustics,finite difference time domain,and finite element methods.

关键词： acoustic lens acoustic black hole gradient index inhomogeneity drop-channel acoustic metamaterials

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Wave Interactions with Multiple semi-Immersed Jarlan-Type Perforated Breakwaters

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China Ocean Engineering 2017年第3期31卷 341-349页

作者： Moussa s. ELBIsY Civil Engineering Department College of Engineering and Islamic Architecture Umm A1-Qura University Makkah 22195 Saudi Arabia

This study examines wave interactions with multiple semi-immersed Jarlan-type perforated breakwaters. A numerical model based on linear wave theory and an eigenfunction expansion method has been developed to study the hydrodynamic characteristics of breakwaters. The numerical results show a good agreement with previous analytical results and experimental data for limiting cases of double partially immersed impermeable walls and double and triple Jarlan-type breakwaters. The wave transmission coefficient Cv; reflection coefficient CR, and energy dissipation coefficient CE coefficients and the horizontal wave force exerted on the front and rear walls are examined. The results show that CR reaches the maximum value when B/L = 0.46n while it is smallest when B/L=0.46n＋0.24 （n=0, 1, 2,...）. An economical triple semi-immersed Jarlan-type perforated breakwater can be designed with B/L = 0.25 and CR and CT ranging from 0.25 to 0.32 by choosing a relative draft d/h of 0.35 and a permeability parameter of the perforated front walls being 0.5 for an incident wave number kh nearly equal to 2.0. The triple semi-immersed Jarlan-type perforated breakwaters with significantly reduced CR, will enhance the structure＇s wave absorption ability, and lead to smaller wave forces compared with the double one. The proposed model may be used to predict the response of a structure in the preliminary design stage for practical engineering.

关键词： Jarlan-type perforated breakwaters analytical solution eigenfimction least squares technique

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semi-solid moulding:Competition to cast and machine from forging in making automotive complex components

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中国有色金属学会会刊：英文版 2010年第S3期20卷 1042-1047页

作者： s.P.MIDsON Aluminium Complex Components Inc 2211 South Jason StreetDenverColorado 80223USA

The very latest technique for impeller manufacture is called semi-solid moulding(ssM).Cummins Turbo Technologies Limited,together with Aluminum Complex Components Inc,developed ssM compressor wheels as a way of achieving cost and durability performance somewhere between that of cast and machined from solid(Mfs) aluminium alloy *** results show ssM material has a superior microstructure and mechanical properties over cast and comparable to Mfs *** testing including durability testing,using accelerated speed cycle tests,proves ssM compressor wheels emerge as being significantly more durable than cast equivalents and approaching that of Mfs *** challenges for semi-solid processing in manufacture of other complex components and other materials in automotive industry in terms of both cost and durability are also discussed.

关键词： aluminum alloys semi-solid moulding durability automotive complex component turbocharger compressor wheel

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An effective round ball tool in electrochemistry process as novel reuse fabrication technology

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中国有色金属学会会刊：英文版 2012年第S3期22卷 825-830页

作者： P.s.PA Department of Digital Content Design Graduate School of Toy and Game DesignNational Taipei University of Education

A reuse fabrication module using micro electrochemistry (MECM) with a round-ball tool to remove the defective In2O3 snO2 thin film from the surfaces of digital paper display was *** etching effect improves that the number of the round-balls decreases for promoting the concentration of electric power and increasing discharge *** a small size of the round-ball tool takes less time for the same amount of In2O3 snO 2 layer removal since the effect of MECM is easily developed for supplying of sufficient electrochemical power.A higher feed rate of the poly ethylene terephthalate (PET) diaphragm combines with enough electric power to drive fast etching rate.A pulsed direct current can improve the effect of dreg discharge and is advantageous to couple this current with the fast feed rate of the *** the ultra-precise etching of In2O 3 snO2,the optoelectronic semiconductor industry can effectively reuse the defective products,reducing production *** precision etching process is of high efficiency and requires only a short period of time to remove the In2O3 snO2 nanostructures.

关键词： thin film round-ball tool In2O3snO2 micro electrochemistry digital paper display

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Induced magnetic field stagnation point flow of nanofluid past convectively heated stretching sheet with Buoyancy effects

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Chinese Physics B 2016年第11期25卷 360-368页

作者： Tanzila Hayat s Nadeem Department of Mathematics Quaid-I-Azam University

This paper presents the buoyancy effects on the magneto-hydrodynamics stagnation point flow of an incompressible,viscous,and electrically conducting nanofluid over a vertically stretching *** impacts of an induced magnetic field and viscous dissipation are taken into *** assisting and opposing flows are *** overseeing nonlinear partial differential equations with the associated boundary conditions are reduced to an arrangement of coupled nonlinear ordinary differential equations utilizing similarity transformations and are then illuminated analytically by using the optimal homotopy investigation strategy（OHAM）.Graphs are introduced and examined for different parameters of the velocity,temperature,and concentration ***,numerical estimations of the skin friction,local Nusselt number,and local sherwood number are explored using numerical values.

关键词： stretching electrically incompressible viscous dissipation ordinary conducting sheet hydrodynamics arrangement

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Influence of Cold Deformation on the Aging Behaviour of Al-Cu-si-Mg Alloy

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Journal of Materials science & Technology 2011年第3期27卷 193-198页

作者： s.K.Ghosh Department of Metallurgy and Materials Engineering Bengal Engineering and Science University

The present study deals with the effect of cold deformation and subsequent aging on the microstructure and mechanical properties of AI-Cu-si-Mg alloy. Differential scanning calorimetry indicates that precipitation occurs in the temperature range of 258-272℃ for the as quenched wrought alloy. The activation energy value estimated by Kissinger method for the aforesaid precipitation reaction is obtained as 106 kJ/mol. 45% cold deformation prior to aging indicates the first dissolution reaction at about 50℃ and the precipitation reaction at a temperature of about 82℃. Microstructural investigations have revealed the formation of fine precipitates within the matrix after aging of the cold deformed sample. As-quenched alloy reveals prominently the aging response, The increase in hardness, yield and tensile strength with simultaneous decrease in elongation in the deformed alloy is found to be primarily due to the deformation strengthening and not due to the precipitation hardening.

关键词： Aluminium alloy Aging Cold deformation Differential scanning calorimetry Kissinger method

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Decentralised dynamic high-gain scaling-based output-feedback control of large-scale non-linear interconnected systems with delays

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Journal of Control and Decision 2014年第4期1卷 257-282页

作者： P.Krishnamurthy f.Khorrami Control/Robotics Research Laboratory(CRRL) Department of ECEPolytechnic Institute of NYUBrooklynNYUSA

A general class of non-linear large-scale interconnected systems is considered,wherein each subsystem is comprised of a nominal part in a general strict-feedback-like structure and a set of appended *** and functional uncertainties and time delays are allowed throughout the overall system structure including the nominal strictfeedback-like parts and appended dynamics of each subsystem as well as the non-linear subsystem *** controller design is based on the dual dynamic highgain scaling technique and provides a robust adaptive delay-independent globally stabilising decentralised output-feedback *** disturbance attenuation properties of the proposed output-feedback decentralised controller to an exogenous disturbance input are also analysed and specific conditions under which properties such as Input-toOutput-practical-stability and asymptotic stabilisation are attained are also discussed.

关键词： non-linear decentralised control large-scale interconnected systems uncertain systems delay systems global stabilisation robust non-linear control

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Magnetic and flotation studies of banded hematite quartzite (BHQ) ore for the production of pellet grade concentrate

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International Journal of Minerals,Metallurgy and Materials 2010年第6期17卷 675-682页

作者： B. Das B.K.Mishra s. Prakash s.K.Das P.s.R.Reddy s.I.Angadi Institute of Minerals and Materials Technology Council of Scientific & Industrial Research (CSIR)

To identify and establish beneficiation techniques for banded hematite quartzite （BHQ） iron ore, a comprehensive research on BHQ ore treatment was carried out. The BHQ ore was assayed as 38.9wt% fe, 42.5wt% siO2, and 1.0wt% Al2O3. In this ore, hematite and quartz are present as the major mineral phases where goethite, martite, and magnetite are present in small amounts. The liberation of hematite particles can be enhanced to about 82% by reducing the particle size to below 63 μm. The rejection of silica particles can be obtained by magnetic and flotation separation techniques. Overall, the BHQ ore can be enriched to 65.3wt% fe at 61.9% iron recovery. A flowsheet has been suggested for the commercial exploitation of the BHQ ore.

关键词： hematite beneficiation magnetic separation flotation pelletizing

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Analysis of mode Ⅲ crack perpendicular to the interface between two dissimilar strips

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Acta Mechanica sinica 2008年第4期24卷 433-438页

作者： M.s.Matbuly Department of Engineering Mathematics and Physics Faculty of Engineering Zagazig University P.O. 44519 Zagazig Egypt

The present work is concerned with the problem of mode Ⅲ crack perpendicular to the interface of a bi-strip composite. One of these strips is made of a functionally graded material and the other of an isotropic material, which contains an edge crack perpendicular to and terminating at the interface. fourier transforms and asymptotic analysis are employed to reduce the problem to a singular integral equation which is numerically solved using Gauss-Chebyshev quadrature formulae. furthermore, a parametric study is carried out to investigate the effects of elastic and geometric characteristics of the composite on the values of stress intensity factor.

关键词： Composite · Interface · Perpendicular crack ·Anti-plane shear stress · fourier transform. singular integral equation

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