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Interf.cial ef.ects in electromagnetic coupling within piezoelectric phononic crystals

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Acta Mechanica Sinica 2009年第1期25卷 95-99页

作者： f. j. Sabina A.B.Movchan Instituto de Investigaciones en Matematicas Aplicadas yen Sistemas Universidad Nacional Autónoma de México Department of.Mathematical Sciences University of Liverpool

In this paper, we discuss waves in piezoelectric periodic composite, with the emphasis on the connection between the electromechanical coupling and the ef.ects of.dispersion of.Bloch-f.oquet waves. A particular attention is given to structures containing interf.ces between dissimilar media and localization of.the electrical f.elds near such interf.ces.

关键词： Piezoelectric periodic composites Interf.ces Dispersion of.Bloch-f.oquet waves

Oxidation and Coatings f.r Power Generation： New Super Ultra Critical Steam Turbines

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中国腐蚀与防护学报 2009年第4期29卷 318-319页

作者： f. j. PErEZ Grupo de Investigacion de Ingenieria de Superf.cies y Materiales Nanoestructurados U. C. M. N°910627 f.cultad de Ciencias Quimicas Universidad Complutense de Madrid. 28040 Madrid Spain

The steels with chromium contents between 9%and 12%wt are used f.r power plants with advanced steam oxidation *** present good creep properties as 9%Cr steels and good oxidation resistance,at the temperatures range between 500℃～600℃.In the last years numerous investigation in development of.coatings has been realized with the aim the protected them against the oxidation in order to allow operation of.steam turbines at 650℃.In this study,Al-Hf.protective coatings were deposited by CVD-f.r on f.rritic steel HCM-12A f.llowed by a dif.usion heat treatment,have shown to be protective at 650℃under steam f.r at least 3000 hours of.laboratory steam exposure under atmospheric *** and composition of.coatings were characterized by dif.erent techniques, such as scanning electron microscopy(SEM),electron probe microanalysis,and X-ray dif.raction(XrD). On the other hand,volatile species by mass spectrometry(MS) and thermogravimetric measurements (TG) during the initial stages oxidation of.the P92 f.rritic steel without and of.Al and Al/Si coating by chemical vapour deposition in f.uidized bed reactors(CVD-f.r) at 650℃in Ar+20%H_2O f.r 150 h were *** order to go f.rward to coatings design the Thermocalc code is used as base f.r the MSdata. TG-MS experiments were conducted in a closed steam loop in order to obtain inf.rmation about the oxyhydroxides f.rmation as reaction between coatings and *** those results the role of.the dif.erent coating element could be established and optimized f.r the coating *** oxidation mechanism based on the TG-MS results is *** morphology/composition and structure of.the oxidized samples were also studied using SEM/EDS and XrD techniques.

关键词：氧化金属腐蚀防护

Multi-scale magnetic resonance measurements and validation of.Discrete Element Model simulations

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Particuology 2011年第4期9卷 330-341页

作者： Christoph r. Müller Daniel j. Holland j.mes r. Third Andrew j. Sederman j.hn S. Dennis Lynn f. Gladden Institute of.Energy Technology Department of Mechanical and Process Engineering Department of.Chemical Engineering and Biotechnology University of Cambridge

This short review describes the capabilities of.magnetic resonance （Mr） to image opaque single- and two-phase granular systems, such as rotating cylinders and gas-f.uidized beds operated in dif.erent f.uidization regimes. The unique capability of.Mr to not only image the solids＇ distribution （voidage） but also the velocity of.the particulate phase is clearly shown. It is demonstrated that Mr can provide measurements over dif.erent length and time scales. With the Mr equipment used f.r the studies summarized here, temporal and spatial scales range f.om sub-millisecond to hours and f.om a f.w hundred micrometres to a f.w centimetres, respectively. Besides providing crucial data required f.r an improved understanding of.the underlying physics of.granular f.ows, multi-scale Mr measurements were also used to validate numerical simulations of.granular systems. It is shown that predictions of.time-averaged properties, such as voidage and velocity of.the particulate phase, made using the Discrete Element Model agree very well with Mr measurements.

关键词： Discrete Element Modelling Magnetic resonance imaging MultiscaleGas-f.uidized beds rotating cylinders

Magnetic Behaviour of.Sm2Co7/f./Sm2 Co7, Nanocomposite Trilayers with Cr and Ti Additions

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Chinese Physics Letters 2009年第3期26卷 255-257页

作者： f. Shahzad S. A. Siddiqi j. Zhou Advaaced Light Source Berkeley Lab University of California Berkeley CA 94720 USA Centre f.r Solid State Physics University of the Punjab Lahore-54590 Pakistan Department of.Physics University of California Berkeley California 94720 USA

Trilayered Sm2Co7/f./Sm2Co7 spring exchange magnets are f.bricated by dc magnetron sputtering on MgO substrates. Very thin layers （0.3-0.7 nm） of.Cr and Ti are added at the interf.ces of.the two magnetic phases. The thickness of.StucCo7 is kept at 20nm and f. at 6nm while the thickness of.Cr and Ti are varied as 0.3, 0.5, and 0.7nm. The base pressure of.sputtering chamber is kept below 10^-7 Torr and Ar pressure at 3-8m Torr. The samples are characterized by x-ray dif.raction （XrD） and SQUID magnetometer. We report improvement in exchange coupling of.nonacomposite magnets by addition of.thin layers of.Cr at interf.ces.

关键词： MAGNETIC materials MAGNETIC properties COMPOSITE materials LAYEr structure (Solids) MICrOf.BrICATION NANOSTrUCTUrED materials ADDITION reactions SAMArIUM

f.brication and Characterization of.SmCo5/f.65Co35 and SmCo5/f. Composite Spring Exchange Magnets

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Chinese Physics Letters 2008年第7期25卷 2642-2644页

作者： f. Shahzad S. A. Siddiqi j. Zhou Centre f.r Solid State Physics University of the Punjab Lahore-54590 Pakistan Department of.Physics University of California Berkeley California-P4720 USA

SmCo5/f.65Co35 and SmCo5/f. spring exchange magnets are f.bricated by dc magnetron sputtering on MgO substrates and 100-nm-thick Si3N4 membranes, respectively. The base pressure of.sputtering chamber is kept below 10^-7 Tort, and Ar pressure is 3 to 8mTorr. The samples are characterized by an x-ray dif.ractometer, a superconducting quantum interf.rence magnetometer, and high resolution magnetic sof. x-ray microscopy. We obtain the complete exchange coupling and single phase behaviour of.composite magnets. The （BH）max value achieved is 28.8 MGOe.

关键词： the power-law exponents precipitation durative abrupt precipitation change

Inf.uence of.Turbulators in Blade Cooling Passages on f.lm Hole Discharge Coef.icients

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j.urnal of.Thermal Science 2004年第3期13卷 245-254页

作者： H.-P. SCHIf.Er j. TAEGE f. HASELBACH rolls-royce Deutschland Eschenweg 11 D-15827 Dahlewitz GermanyRolls-Royce Deutschland Eschenweg 11 D-15827 Dahlewitz GermanyRolls-Royce Deutschland Eschenweg 11 D-15827 Dahlewitz Germany

This paper details the results of.a j.int proj.ct between rolls-royce Deutschland (rrD) and the Northwestern Polytechnical University of.China (NWPU). The obj.ctive of.the proj.ct was the determination of.the inf.uence of.tabulators in turbine blade cooling passages on f.lm hole discharge coef.icients (Cd coef.icients). A large-scale plexiglas model was used by the NWPU to measure the turbulator inf.uence on Cd coef.icients f.r a wide range of.dif.erent geometrical parameters, reynolds numbers and cooling f.ow of. take ratios. rrD specif.ed the comprehensive test matrix and analysed the test data. The Cf. code f.UENT was used by rrD f.r numerical simulation of.the test cases with the main obj.ctive to support the interpretation of.observed trends. Both, experimental and numerical results will be presented in this paper f.r a selection of.test conf.gurations.

关键词： f.lm hole discharge coef.icient turbulator blade cooling.

Ef.ect of.Alloying Additions on the Oxidation of.High Speed Steels under Dry and Wet Conditions

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中国腐蚀与防护学报 2009年第4期29卷 241-247页

作者： f. C. rIZZO M. j. MONTEIrO S. r. j. SAUNDErS DCMM PUC Rio de Janeiro Brazil Bentley Surrey UK

An investigation has been carried out into the ef.ects of.chromium and vanadium content on the oxidation rate and on the adhesion of.oxide scales grown on three dif.erent chemical compositions of.high speed steels under dry and wet *** oxidation tests were carried out in a thermobalance at 650℃f.r up to 14.4 *** mass gain of.the specimens increased with increasing contents of.water vapour. Alloy composition had no ef.ect on the oxidation rate in dry ***'adhesion'of.the oxide scale was determined using indentation with a rockwell C diamond and the pull adhesion test to determine the interf.cial toughness and the tensile strength of.the oxide metal bond,***,the results of.the investigation indicated that oxide adhesion was lowest f.r the specimens exposed to dry conditions, and that with increasing water vapour content,the scale was more *** test results showed that an increase in the V concentration was deleterious to oxide adhesion in both the dry and wet environments,whereas an increase in the Cr-content had little ef.ect on adhesion.

关键词：合金腐蚀氧化金属材料

Diameter-dependent in vitro perf.rmance of.biodegradable pure zinc wires f.r suture application

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j.urnal of.Materials Science & Technology 2019年第8期35卷 1662-1670页

作者： H. Guo r.H. Cao Y.f. Zheng j. Bai f. Xue C.L. Chu State Key Laboratory f.r Turbulence and Complex System and Department of.Materials Science and Engineering College of Engineering Peking University Beijing 100871 China School of.Materials Science and Engineering Southeast University Nanjing 211189 China Key Laboratory f.r Advanced Metallic Materials Southeast University Nanjing 211189 China

In this study, biodegradable pure zinc wires with 3.0 mm and 0.3 mm in diameter were prepared via hot-extrusion and subsequent cold-drawing process respectively. The microstructure, mechanical perf.rmance, corrosion behavior, in vitro cytocompatibility and antibacterial ef.ect were comparatively *** cold-drawing, the mechanical property, especially the elongation of.the ф0.3 mm pure Zn wire was improved signif.cantly compared with the ф3.0 mm pure Zn wire. The in vitro corrosion study including immersion and electrochemical test showed acceptable corrosion resistance of.these two materials in Hank's solution. The in vitro Human Umbilical Vein Endothelial Cells(HUVECs) viability assay showed obviously dif.erent results, in which the ф0.3 mm pure Zn wire demonstrated f.vorable cytocompatibility, while the ф3.0 mm wire exhibited severe cytotoxic ef.ect with 100% extract concentration. Both of.them exhibited partly antibacterial ef.ect on S. aureus. These results demonstrated the f.asibility of.the prepared 0.3 mm pure Zn wire as the potential suture material with good absorbability.

关键词： Pure zinc Wire Biodegradable metal Suture

Light metal compound casting

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Science China(Technological Sciences) 2009年第1期52卷 46-51页

作者： Konrad j. M. PAPIS j.erg f. LOEf.LEr Peter j. UGGOWITZEr ETH Zurich Laboratory of Metal Physics and Technology Wolfgang-Pauli-Str. 10

‘Compound casting’simplif.es j.ining processes by directly casting a metallic melt onto a solid metal substrate. A continuously metallurgic transition is very important f.r industrial applications, such as j.int structures of.spacef.ame constructions in transport industry. In this proj.ct, ‘compound casting’ of.light metals is investigated, aiming at weight-saving. The substrate used is a wrought aluminium alloy of.type AA5xxx, containing magnesium as main alloying element. The melts are aluminium alloys, containing various alloying elements (Cu, Si, Zn), and magnesium. By replacing the natural oxygen layer with a zinc layer, the inherent wetting dif.iculties were avoided, and compounds with f.awless interf.ces were successf.lly produced (no contraction def.cts, cracks or oxides). Electron microscopy and EDX investigations as well as optical micrographs of.the interf.cial areas revealed their continu- ously metallic constitution. Dif.usion of.alloying elements leads to heat-treatable microstructures in the vicinity of.the j.ining interf.ces in Al-Al couples. This permits signif.cant variability of.mechanical properties. Without signif.cantly cutting down on wettability, the f.rmation of.low-melting intermetallic phases (Al3Mg2 and Al12Mg17 IMPs) at the interf.ce of.Al-Mg couples was avoided by applying a protective coating to the substrate.

关键词： compound casting aluminium alloys magnesium alloys interf.ce structure