简介:WehavestudiedtheangularmagnetoresistanceofironpnictidesBaFe2-xNixAs2,whichshowsclear180degreeperiodicityasfittedbyacosinefunction.Inthex=0.065sample,thephaseofthetwo-foldsymmetrychanges90degreesabovethetetragonal-to-orthorhombicstructuraltransitiontemperatureTs.Sincethephaseatlowtemperatureisassociatedwiththerotationoforthorhombicdomainsbymagneticfield,weshowthatevenvacuumgreasecanpushthepresenceoforthorhombicdomainsattemperaturesmuchhigherthanTs.Ourresultssuggestthatresidualstressmayhavesignificanteffectsinstudyingthenematicordersanditsfluctuationsinironpnictides.
简介:WeinvestigateindetailtheeffectsofR-parityleptonnumberviolationonthedecay~↑b1→b~↑x1^0intheR-parityviolatingminimalsupersymmetricstandardmodel(Rp-MSSM)underthepresentexperimentalconstraintsonRpparameters.Inournumericalcalculationsweconsidertwocasesofinputparametersofthesquarkandsleptonsectors,MsquarkMslepton,forcomparison.TheresultsshowthattherelativeR-parityviolatingcorrectionisnotverysensitivetothemassofthelightestneutralino-0↑x1andthedegenerateR-parityviolatingcouplingparameterλ2′,butstronglydependsonMsquark,Mslepton,tanβandthedegenerateR-parityviolatingcouplingparameterλ1′.Therelativecorrectionisabout-4~3%andcanexceed-6%insomeregionofparameterspace.Therefore,preciseexperimentanalysesonthedecay~↑b1→b~↑x1^0mayprovideaprobeoftheR-parityviolation.
简介:TodepictthedetailsthatCHOP(C/EBPhomologousprotein)regulatesautophagyandapoptosisinbreastcancercells,theexpressionofCHOPwasinhibitedbytransfectionwithsiRNAsequence.AsshowninFig.1,radiati-Fig.1CHOPinhibitionbysiRNAatmRNAandproteinlevelsafterradiation.onelicitedahigherexpressionofCHOPintheNCgroupcomparedwithcontrol.However,thishigherexpressionwassignificantlyinhibitedinthesiRNAgroup.
简介:Twotransmissioncurvedcrystalspectrometersaredesignedtomeasurethehardx-rayemissioninthelaserfusionexperimentofComptonradiographyofimplosiontargetonShenGuang-IIIlaserfacilityinChina.Cylindricallycurvedα-quartz(10–11)crystalswithcurvatureradiiof150and300mmareusedtocoverspectralrangesof10–56and17–100keV,respectively.Thedistancebetweenthecrystalandthex-raysourcecanbechangedoverabroaddistancefrom200to1500mm.Theopticaldesign,includingtheintegralreflectivityofthecurvedcrystal,thesensitivity,andthespectralresolutionofthespectrometers,isdiscussed.WealsoprovidemechanicdesigndetailsandexperimentalresultsusingaMoanodex-raysource.High-qualityspectrawereobtained.Weconfirmedthatthespectralresolutioncanbeimprovedbyincreasingtheworkingdistance,whichisthedistancebetweentherecordingmediumandtheRowlandcircle.
简介:ThedetailedmicrostructuresofNi80Fe20/Fe50Mn50superlatticeshavebeencharacterizedusingbothx-raydiffractiontechniquesandtransmissionelectronmicroscopy.Theobrivouslayeredstructure,typicalcolumnstructureandtwinswhichexistinNi80Fe20/Fe50Mn50superlatticeswereobservedthroughperformingtransmissionmicroscopy.Bycombiningthetechniqueoflowanglex-rayreflectivity(specularandoff-specularscans)withtheanomalousscatteringeffectandhigh-anglex-raydiffraction(usingconventionalx-ray),wequantitativelyanalysedthemicrostructuralvariationasafunctionofannealingtemperature.Itisfoundthatthelateralcorrelationlength,the(111)peakintensityofthesuperlatticesandtheaveragemultilayercoherencelengthallincreasewithariseinannealingtemperatureannealingcandecreasetherootmean-squareroughnessattheinterfacesofNi80Fe20/Fe50Mn50superlattices.theobtainedmicrostructuralknowledgewillbehelpfulinunderstandingthemagneticpropertiesoftheni80Fe20/Fe50Mn50exchangebiassystem.
简介:Wereportthatβ’-Gd2(MoO4)3crystalshavebeengrownbytheCzochralski(CZ)method.Westudiedthegrowthconditionsfoβ’-Gd2(MoO4)3crystal.Acompatisonbetweentheresistance-heatedmethodandradiofrequencyinduction-heatedmethodisdescribed.Also,theinsituobservationofthedomainstructurebythemicroscopeandbysynchrotronradiationX-raytopographyundertheconditionsofDCpolarizationvoltageandtempertaturechangewerecarriedout.Experimentsshowedthatmultidomainstructureincludingferroelectricandferroelasticdomainsoccurredinβ’-Gd2(MoO4)3cystal.Usuallyferroeletiricdomainsappearedintheas-growncrystalandferroelasticdomainsappearedinthepolishedthinnerpiece.BothferroelectricandferroelasticdomainsdisappearedwhenthetemperatureofthecrystalpiecewashigherthantheCurietempperatureTcandtheycouldbereproducedwhenthetemperatureofthecrystalpiecewasloweredbelowTC.WhenaDCpolarizationvoltagerangingfrom150to500Vwasappliedonac-axisβ’-Gd2(MoO4)3piecehavingathicknessof0.5mm,themultidomainwouldgraduallytransformtoasingledomain.Thisresualmeansthatitispossibletomakeaperiodicallypoledβ’-Gd2(MoO4)3crystal.2001ElsevierScienceB.V.Allrightsreserved.
简介:Si-richsiliconnitridefilmsarepreparedbyplasma-enhancedchemicalvapordepositionmethod,followedbythermalannealingtoformtheSinanocrystals(Si-NCs)embeddedinSiNxfloatinggateMOSstructures.Thecapacitance–voltage(C–V),current–voltage(I–V),andadmittance–voltage(G–V)measurementsareusedtoinvestigatethechargingcharacteristics.Itisfoundthatthemaximumflatbandvoltageshift(△VFB)duetofullchargedholes(~6.2V)ismuchlargerthanthatduetofullchargedelectrons(~1V).ThechargingdisplacementcurrentpeaksofelectronsandholescanbealsoobservedbytheI–Vmeasurements,respectively.FromtheG–VmeasurementswefindthattheholeinjectionisinfluencedbytheoxideholetrapswhicharelocatedneartheSiO2/Si-substrateinterface.CombiningtheresultsofC–VandG–Vmeasurements,wefindthattheholechargingoftheSi-NCsoccursviaatwo-steptunnelingmechanism.TheevolutionofG–VpeakoriginatedfromoxidetrapsexhibitstheprocessofholeinjectionintothesedefectsandtransferringtotheSi-NCs.
简介:Ceriumoxidenanoparticlescoatedbysodiumbis(2-ethylexyl)sulphosuccinate(AOT)werepreparedbyusingamicroemulsionmethod.Transmissionelectronmicroscopyrevealedanaverageparticlesiaeof2-3nm.X-raydiffractionshowedthattheceriumoxidenanoparticlesretaintheCeF2-typecubicstructureslikethebulkcrystal.Theintermediatevalenceofformallytetravalentcompoundshadbeendetectedbyx-ray-absorptionnear-edgestructetravalentcompoundshadbeendetectedbyx-ray-absorptionnear-degestructure(XANES)spectraofCeLIIIabsorptioninbulkCeO2andtheceriumoxidenanoparticles.Twowellresovedwhitelinescanbeassignedtotheelectronconfigurationsof4f^0Land4f^1L,respectively,whereLdenotesaligandhole.Atthesametime,theceriumoxidenanoparticlesalsoshowedthestructuralfeatresoftrivalentcompounds,incomparisontothetrivalentCe(NO3)3·6H2O.FuorLorentzianfunctionsandtwoarctanfunctionswereusedtofitthenormalizedXANESspectra.Theextendedx-ray-absorptionfine-structure(EXAFS)techniquewasusedtoprobethelocalatomicstructuresaroundtheabsorberCe.ThemultielectrornexcitationeffectontheEXAFSspectrawaseliminated.Acor-shellmodelwasusedtodeducethenear-neighbourstructuralparametersaroundcerium.BulkCeO2witheightoxygenatomslocatedat2.343AwasusedasthereferencesampletoextractthebackscatteringamplitudeandphaseshiftoftheCe-Obond.OnehalfoftheatomelocateatthecorepartwiththeCeF2-typecubicstructures(eightoxyensat2.343AaroundCe),theotherhalfoftheatomsareamorphousphaselocatedintheshellpart(surfaceofthenanoparticles)withapproximatelyCe2O3structuralfeatures(averageedsevenoxygensat2.50AaroundCe).
简介:Tonguesquamouscellcarcinoma(ToSCC)isthemostcommontypeofheadandnecksquamouscellcarcinomaandisthesixthleadingcauseofcancerdeathsworldwide[1].Inclinicaloncology,radiationtherapyisastandardtreatmentusedfortumors.Numerousstudieshaveshownthatconventionalradiotherapyusedincancertreatmentmayincreasetheriskofmetastasisofmalignanttumorcells[2–4].Toimprovepatientsurvival,thepotentialformetastasisoftumorsinresponsetoradiationneedstobeaddressed.