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The composition dependent mechanical properties of ge si core–shell nanowires

The composition dependent mechanical properties of ge si core–shell nanowires

The composition dependent mechanical properties of ge si core–shell nanowires

... size -dependent band gaps of Ge- core /Si- shell and Si- core /Ge- shell nanowires at the level of density functional theory, where the composition is definedas the ratio of the number of atoms of the ... around the interface somehowcorrelates with the composition of the core–shell nanowire.These aspects are reflected in the averaged bond lengths of Si Si, Ge Ge and Si Ge varying with the composition ... 2008Abstract The Stillinger–Weber potential is used to study the composition- dependent Young’s modulus for Ge- core /Si- shell and Si- core /Ge- shell nanowires. Here, the composition is defined as a ratio of the...
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Tài liệu MECHANICAL PROPERTIES OF THE HEART AND ITS INTERACTION WITH THE VASCULAR SYSTEM ppt

Tài liệu MECHANICAL PROPERTIES OF THE HEART AND ITS INTERACTION WITH THE VASCULAR SYSTEM ppt

... as the pressure of the left upper corner of the loop; the sig-nificance of this pressure will be discussed in detail below. Moving to the bottom of the loop, we can reason that the pressure of ... possible to characterize the time course of change in ventricular mechanical properties by plotting the time course of change in the slope of the instantaneous PVR. Above, we referred to the ... measure of the arterial properties and therefore is not useful within the context of indexing the afterload of the ventricular chamber. Page 18 of 23 IX. QUANTIFYING THE DETERMINANTS OF...
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Tài liệu Mechanical Properties of Engineered Materials P2 pptx

Tài liệu Mechanical Properties of Engineered Materials P2 pptx

... Inc.ÆÀ1¼1=5boundaryisoneinwhich1in5ofthegrainboundaryatomsmatch,asshowninFig.2.8(c).Twinboundariesmayformwithincrystals.Suchboundarieslieacrossdeformationtwinplanes,asshowninFig.2.8(d).Notethattheatomsoneithersideofthetwinplanesaremirrorimages.Stackingfaultsmayalsobeformedwhentheperfectstackinginthecrystallinestackingsequenceisdisturbed,Figs2.8(e)and2.8(f).Thesemaybethoughtofastheabsenceofaplaneofatoms(intrinsicstackingfaults)ortheinsertionofrowsofatomsthatdisturbthearrangementofatoms(extrinsicstackingfaults).IntrinsicandextrinsicstackingfaultsareillustratedschematicallyinFigs2.8(e)and2.8(f),respectively.NotehowtheperfectABCABCstackingofatomsisdisturbedbytheinsertionorabsenceofrowsofatoms.2.3.4VolumeDefectsVolumedefectsareimperfectionssuchasvoids,bubble/gasentrapments,porosity,inclusions,precipitates,andcracks.Theymaybeintroducedintoasolidduringprocessingorfabricationprocesses.AnexampleofvolumedefectsispresentedinFig.2.9.ThisshowsMnSinclusionsinanA707steel.AnotherexampleofavolumedefectispresentedinFig.1.16(d).This ... Inc.whichisgivensimplybyÀðCAÀCBÞ=r0,thediffusionflux,J,maythenbeexpressedasJ¼D0expÀqkTdCdxð2:9ÞIfwescalethequantityqbytheAvogadronumber,thentheenergytermbecomesQ¼NAqandR¼kNA.Equation(2.9)maythusbeexpressedasJ¼ÀD0expÀQRTdCdxð2:10ÞIfwenowsubstituteD¼ÀD0expÀQRTintoEq.(2.10),weobtaintheusualexpressionforJ,i.e.,JisgivenbyJ¼ÀDdCdxð2:11ÞTheaboveexpressionisFick’sfirstlawofdiffusion.Itwasfirstpro-posedbyAdolfHicksin1855.Itisimportanttonoteherethatthediffusioncoefficientforself-diffusion,D,canhaveastrongeffectonthecreepproper-ties,i.e.,thetime -dependent owofmaterialsattemperaturesgreaterthan$0.3–0.5ofthemeltingtemperatureindegreesKelvin.Also,theactivationenergy,Q,inEq.(2.10)isindicativeoftheactualmechanismofdiffusion,whichmayinvolvethemovementofinterstitialatoms[Fig.2.11(a)]andvacancies[Fig.2.11(b)].Diffusionmayalsooccuralongfastdiffusionpathssuchasdislocationpipesalongdislocationcores[Fig.2.12(a)]orgrainboundaries[Fig.2.12(b)].This ... Inc.whichisgivensimplybyÀðCAÀCBÞ=r0,thediffusionflux,J,maythenbeexpressedasJ¼D0expÀqkTdCdxð2:9ÞIfwescalethequantityqbytheAvogadronumber,thentheenergytermbecomesQ¼NAqandR¼kNA.Equation(2.9)maythusbeexpressedasJ¼ÀD0expÀQRTdCdxð2:10ÞIfwenowsubstituteD¼ÀD0expÀQRTintoEq.(2.10),weobtaintheusualexpressionforJ,i.e.,JisgivenbyJ¼ÀDdCdxð2:11ÞTheaboveexpressionisFick’sfirstlawofdiffusion.Itwasfirstpro-posedbyAdolfHicksin1855.Itisimportanttonoteherethatthediffusioncoefficientforself-diffusion,D,canhaveastrongeffectonthecreepproper-ties,i.e.,thetime -dependent owofmaterialsattemperaturesgreaterthan$0.3–0.5ofthemeltingtemperatureindegreesKelvin.Also,theactivationenergy,Q,inEq.(2.10)isindicativeoftheactualmechanismofdiffusion,whichmayinvolvethemovementofinterstitialatoms[Fig.2.11(a)]andvacancies[Fig.2.11(b)].Diffusionmayalsooccuralongfastdiffusionpathssuchasdislocationpipesalongdislocationcores[Fig.2.12(a)]orgrainboundaries[Fig.2.12(b)].This...
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Tài liệu Mechanical Properties of Engineered Materials P1 pptx

Tài liệu Mechanical Properties of Engineered Materials P1 pptx

... Inc.Nevertheless,theymaybeimportantindeterminingtheactualphysicalstatesofmaterials.VanderWaals’forcesarefoundbetweencovalentlybondednitrogen(N2)molecules.TheywerefirstproposedbyVanderWaalstoexplainthedeviationsofrealgasesfromtheidealgaslaw.Theyarealsopartlyresponsibleforthecondensationandsolidificationofmole-cularmaterials.1.3.2.2HydrogenBondsHydrogenbondsareinducedasaresultofpermanentdipoleforces.Duetothehighelectronegativity(powertoattractelectrons)oftheoxygenatom,thesharedelectronsinthewater(H2O)moleculearemorestronglyattractedtotheoxygenatomthantothehydrogenatoms.Thehydrogenatomthere-forebecomesslightlypositivelycharged(positivedipole),whiletheoxygenatomacquiresaslightnegativecharge(negativedipole).Permanentdipoleattractions,therefore,developbetweentheoxygenandhydrogenatoms,givingrisetobridgingbonds,asshowninFig.1.6(b).Suchhydrogenbondsarerelativelyweak(0.04–0.40kcal/mol).Nevertheless,theyarerequiredtokeepwaterintheliquidstateatroom-temperature.Theyalsoprovidetheadditionalbindingthatisneededtokeepseveralpolymersinthecrystallinestateatroomtemperature.1.4STRUCTUREOFSOLIDSThebondedatomsinasolidtypicallyremainintheirlowestenergyconfig-urations.Inseveralsolids,however,noshort-orlong-rangeorderisobserved.Suchmaterialsareoftendescribedasamorphoussolids.Amorphousmaterialsmaybemetals,ceramics,orpolymers.Manyaremetastable,i.e.,theymightevolveintomoreorderedstructuresonsub-sequentthermalexposure.However,therateofstructuralevolutionmaybeveryslowduetoslowkinetics.1.4.1PolymersThebuildingblocksofpolymersarecalledmers[Figs1.7(a)and1.7(b)].These ... in all of the electronicpackages that are used in modern electronic devices. Since the reliability of these packages is often determined by the thermal and mechanical prop-erties of the individual ... Inc.(f.c.c.)structurehasanABCABCstackingsequence.Also,bothf.c.c.andh.c.p.structuresareclosedpackedstructureswithseveralclosed-packedplanesonwhichplasticflowcanoccur.Crystallineceramicmaterialsgenerallyhavemorecomplexstructureswithlowersymmetry.Ingeneral,however,14Bravaislatticesarepossibleincrystallinematerials,asshowninFig.1.11.NotetheincreasingcomplexityandthereductioninsymmetryoftheBravaislatticesthatdonothavecubicorhexagonalcrystalstructures.Crystallinecermicshavelesssymmetricstructures.Thelossofsymmetryispartlyresponsiblefortherelativelybrittlebehaviorthatistypicallyobservedinceramicsystems.Thiswillbediscussedlater.FurtherdiscussiononBravaislatticescanbefoundinanystandardtextoncrystallography.1.4.3IntermetallicsIntermetallicsarecompoundsformedbetweendifferentmetals.Thebondsareoftenmixedmetallicandcovalentbonds.However,mostintermetallicsareoftenmetallic-likeincharacter.Intermetallicsare,therefore,generallystrong,butbrittleasaresultoftheirmixedbondingcharacter.Theyalsohavepredominantlynoncubic(nonsymmetric)structures.Nevertheless,(relatively)lightweight,high-temperatureintermetallicssuchasgamma-basedtitaniumaluminides(TiAl)andniobiumaluminides(Nb3Al)areofcommercialinterest,especiallyintheaerospaceindustrywheretheyarebeingconsideredaspossiblereplacementsforheaviernickel-,iron-,orcobalt-basesuperalloys,themselvesoftencontainingintermetallics(Fig.1.13).Somerecentimprovementsinthebalanceofpropertiesofthesemate-rialssuggeststhattheymaybeusedinthenextgenerationofaircrafttur-bines.1.4.4SemiconductorsThese are typically group IV elements (or their compounds)...
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Tài liệu Báo cáo khoa học: The antibacterial and antifungal properties of trappin-2 (pre-elafin) do not depend on its protease inhibitory function pptx

Tài liệu Báo cáo khoa học: The antibacterial and antifungal properties of trappin-2 (pre-elafin) do not depend on its protease inhibitory function pptx

... source of nitrogen [15], thereby competing with the antibacterialeffect of trappin-2. However, none of the bacteriatested destroyed trappin-2 in the incubation mixtures,suggesting that another, ... leakage of the cytoplasmic content of damaged bacterial or fungalcells.Discussion The main physiological function attributed to elafinand ⁄ or trappin-2 and its precursor is the protection of tissues ... 2). The mutant appeared to besignificantly more active against S. aureus than waswild-type trappin-2. Taken together, this suggests that the antimicrobial activity of trappin-2 is independent of its...
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Tài liệu Báo cáo khoa học: A comparative analysis of the time-dependent antiproliferative effects of daunorubicin and WP631 pdf

Tài liệu Báo cáo khoa học: A comparative analysis of the time-dependent antiproliferative effects of daunorubicin and WP631 pdf

... verify that the relativelylow uptake of WP631 was at the origin of the low apoptosis,and whether longer periods of treatment could causesignificant apoptosis in the presence of this bisintercalator.Flow ... USA) at the ÔServeis Cientifico-TecnicsÕ of the University of Barcelona,using the 488 nm line of an argon laser and standard opticalemission filters. Percentages of cells at each phase of the cellcycle ... on the levels of p53 protein [16], suggests that the extent of p53 -dependent apoptosis is not a critical factor in the sensitivity to WP631 [16]. Although it is widely acceptedthat the sensitivity...
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Tài liệu PHYSICAL, CHEMICAL, AND MECHANICAL PROPERTIES OF BAMBOO AND ITS UTILIZATION POTENTIAL FOR FIBERBOARD MANUFACTURING docx

Tài liệu PHYSICAL, CHEMICAL, AND MECHANICAL PROPERTIES OF BAMBOO AND ITS UTILIZATION POTENTIAL FOR FIBERBOARD MANUFACTURING docx

... investigated the effects of age of bamboo fibers and the resin content level on the physical and mechanical properties of the manufactured fiberboards. 1.2 Objectives The overall objective of this ... Chemical Composition 2.1 Introduction The chemical composition of bamboo is similar to that of wood. Table 2-2 shows the chemical composition of bamboo [Higuchi 1957]. The main constituents of ... [Leithoff and Peek 2001]. Since the amount of each chemical composition of bamboo varies with age, height, and layer, the chemical compositions of bamboo are correlated with its physical and mechanical...
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Báo cáo

Báo cáo " Study on the characteristics and catalytic properties of Pt/SBA-15 in the selective oxidation of D-Glucose " potx

... very small nano sizes was dispersed inside the pore of support material. 3.3. Catalytic activities of Pt/SBA-15 in the oxidation of D-glucose The results of the oxidation of D-glucose carried ... showed the highest activity and selectivity in the oxidation of glucose. When increasing the content of Pt loading, most Pt nanoparticles aggregated outside the channels of SBA-15 with size of ... that of the catalyst with 2 and 3% Pt contents, which has an average particle size of 10-15 nm (TEM images) explained for this difference. On the other hand, Pt nanoparticles existed inside the...
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Báo cáo khoa học: Ibuprofen binding to secondary sites allosterically modulates the spectroscopic and catalytic properties of human serum heme–albumin doc

Báo cáo khoa học: Ibuprofen binding to secondary sites allosterically modulates the spectroscopic and catalytic properties of human serum heme–albumin doc

... [20]:koff¼ðkoffð2ÞÂð½ibuprofen=ðK2½ibuprofenÞþðkoffð3ÞÂð½ibuprofen=ðK3½ibuprofenÞÞ þ kþoffð7Þwhere koff(2)and koff(3)indicate values of koffoccurring atK2< [ibuprofen] ... indicates that the removal of domain I from HSA does not significantlyaffect the functional and structural properties of domains I and II [i.e. of the 1–382 region of (t)HSA].l The values of the Hill ... Analysis of the dependence of the molar fraction of the ibuprofen-bound tHSA–heme-Fe(II)-NO (Y) on the ibuprofenconcentration (Fig. 4), according to Eqn (5), allowedto determine the value of the...
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Báo cáo khoa học: Protein transport in organelles: The composition, function and regulation of the Tic complex in chloroplast protein import pptx

Báo cáo khoa học: Protein transport in organelles: The composition, function and regulation of the Tic complex in chloroplast protein import pptx

... Additionally,because the demand of the chloroplast is ‘sensed’inside the organelle, the IEM is closest to the origin of the signal, and thus regulation at the Tic complexcould be one of the fastest ways to ... enhance the ATPase activity of the chaperone Hsp93. The motor activity of this AAA+ ATPase probably accounts formost of the ATP requirement of the import reaction, exerting the pulling force on the ... characterization of the single domains pro-vided valuable insight into the possible functionalrole of Tic40: the Sti1-like region of Tic40 wasshown to be functionally equivalent to the Sti1domain of human...
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