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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

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.

Sexual selection af.ects the sizes of.the mammalian prostate gland and seminal vesicles

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Current Zoology 2009年第1期55卷 1-8页

作者： Matthew j. ANDERSON Alan f. DIXSON Conservation and Research f.r Endangered Species Zoological Society of San Diego School of.Biological Sciences Victoria University of Wellington

The accessory reproductive glands of.male mammals contribute the bulk of.the secretions in which spermatozoa are transported to the f.male tract during copulation. Despite their morphological diversity, and the chemical complexity of.their products, little is known about the possible ef.ects of.sexual selection upon these glands in mammals. Here we consider the seminal vesicles and prostate glands in a sample of.89 species and 60 genera representing 8 Orders of.mammals. The sizes of.the accessory glands are analysed in relation to body weight and testes weight. Both the seminal vesicles size and prostate size （corrected f.r body weight） correlate positively with relative testes size in this sample; this f.nding remains highly signif.cant af.er application of.procedures to correct f.r possible phylogenetic biases in the data set. The accessory reproductive glands are also signif.cantly larger in those mammals which have large relative testes sizes, and in which the likelihood of.sperm competition is greatest. These results support the hypothesis that sexual selection has played an important role in the evolution of.the mammalian prostate gland and seminal vesicles.

关键词： Mammals Prostrate gland Seminal vesicles Sexual selection Sperm competition

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

Compost Input Ef.ect on Dryland Wheat and f.rage Yields and Soil Quality

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Pedosphere 2018年第3期28卷 451-462页

作者： f.ancisco j. CALDERON Merle f. VIGIL j.seph BENj.MIN United States Department of.Agriculture-Agricultural Research Service (USDA-ARS) Central Great Plains Research Station Akron80720 CO( USA)

Organic agricultural systems rely on organic amendments to achieve crop f.rtility requirements, and weed control must be achieved without synthetic herbicides. our obj.ctive was to determine the crop yield and soil quality as af.ected by a transition f.om grass to dryland organic agriculture in the Central Great Plains of.North America. This study evaluated three beef.f.edlot compost(Bf.)treatments in 2010–2015 f.llowing biennial application rates: 0(control), 22.9, and 108.7 t ha^(-1) on two dryland organic cropping systems: a wheat(Triticum aestivum)-f.llow(Wf. rotation harvested f.r grain and a triticale(Triticosecale)/pea(Pisum sativum)-f.llow(T/P-f. rotation harvested f.r f.rage. The triticale + pea biomass responded positively to the 108.7-t ha^(-1) Bf. treatment,but not the 22.9-t ha^(-1) Bf. treatment. The wheat biomass was not af.ected by Bf. addition, but biomass N content *** f.edlot compost input did not increase wheat grain yields, but had a positive ef.ect on wheat grain Zn content. Soil total C and N contents increased with the rate of.108.7 t ha^(-1) Bf. af.er three applications, but not with 22.9 t ha^(-1) Bf.. Soil enzyme activities associated with N and C cycling responded positively to the 108.7-t ha^(-1) Bf. treatment. Saturated salts were high in the soil receiving 108.7 t ha^(-1) of.Bf., but did not af.ect crop yields. These results showed that Bf. was ef.ective in enhancing f.rage yields, wheat grain quality, and soil C and N, as well as specif.c microbial enzymes important f.r nutrient cycling. However, the large rates of.Bf. necessary to elicit these positive responses did not increase grain yields, and resulted in an excessive buildup of.soil P.

关键词： organic agriculture soil C soil enzyme activity soil N pea triticale

The evolution of.Hessian f.y f.om the Old World to the New World： Evidence f.om molecular markers

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Insect Science 2015年第6期22卷 768-784页

作者： Brandon j. Schemerhom Yan Ma Crane Charles f. Crane USDA-ARS Department of.Entomology Department of.Botany and Plant Pathology Purdue University West Lafayette IN 47907USA

Eighteen polymorphic microsatellite loci and 11 single-nucleotide polymor- phisms were genotyped in 1 095 individual Hessian f.y specimens representing 23 popula- tions f.om North America, southern Europe, and southwest Asia. The genotypes were used to assess genetic diversity and interrelationship of.Hessian f.y populations. While phyloge- netic analysis indicates that the American populations most similar to Eurasian populations come f.om the east coast of.the United States, genetic distance is least between （Alabama and Calif.rnia） and （Kazakhstan and Spain）. Allelic diversity and f.equency vary across North America, but they are not correlated with distance f.om the historically documented point of.introduction in New York City or with temperature or precipitation. Instead, the greatest allelic diversity mostly occurs in areas with Mediterranean climates. The mi- crosatellite data indicate a general def.ciency f.r heterozygotes in Hessian f.y. The North American population structure is consistent with multiple introductions, isolation by dis- tance, and human-abetted dispersal by bulk transport of.puparia in inf.sted straw or on harvesting equipment.

关键词： allele f.equency Hessian f.y microsatellite population structure SNP SSR