简介：Theultra-compactbiosensorbasedonthetwo-dimensional(2D)photoniccrystal(PhC)microcavityisinvestigated.TheperformancesofthesensorareanalyzedtheoreticallyusingtheFabry-Perot(F-P)cavitymodelandsimulatedusingthefinite-differencetime-domain(FDTD)method.Thesimulationresultsgoalongwiththetheoreticalanalysis.

简介：Weinvestigatedtheeffectofphotodynamictherapy(PDT)withhematoporphyrinmonomethylether(HMME)ontheviabilityofStreptococcusmutans(S.mutans)cellsonbiofilmsinvitro.Streptococcusmutansistheprimaryetiologicalagentofhumandentalcaries.Sincedentalcariesarelocalizedinfections,suchplaque-relateddiseaseswouldbewellsuitedtoPDT.Thediodelaserusedinthisstudyhadthewavelengthof635nm,whoseoutputpowerwas10mWandtheenergydensitywas12.74J/cm~2.HMMEwasusedasphotosensitizer.Sampleswerepreparedanddividedintofivegroups:(1)HMME;(2)Laser;(3)HMME+Laser;(4)Controlgroup(+)withchlorhexidine;and(5)Controlgroup(-)withsterilephysiologicalsaline.InoculumofS.mutansincubatedwithHMMEalsoexaminedwithfluorescencemicroscopy.PDTexhibitedasignificantly(P<0.05)increasedantimicrobialpotentialcomparedwith20μm/mLHMMEonly,laseronly,0.05%chlorhexidine,and0.9%sterilephysiologicalsaline,whichreducedtheS.mutansofthebiofilmmosteffectively.Laserand0.05%chlorhexidinewerecausedreductionintheviablecountsofS.mutanssignificantlydifferent(P<0.05)also,butthesetwotesttreatmentsdidnotstatisticallydifferfromeachother.HMMEgroupdidnotstatisticallydifferwithnegativecontrolgroup.FluorescencemicroscopyindicatedthatHMMElocalizedprimarilyintheS.mutansofthebiofilm.ItwasdemonstratedthatHMME-mediatedPDTwasefficientatkillingS.mutansofbiofilmsandausefulapproachinthetreatmentofdentalplaque-relateddiseases.

简介：Thetime-of-flightmassspectrum(TOFMS)relativetotheresonanttwo-photonionizationofgasphasep-dichlorobenzenewasobtainedinthewavelengthrangeof240-250nmbyahome-madesystem.Aspecialdesignwasmadetoreducetheeffectofmemoryontheinnerwallofthesampleinletsystemsuitablefortheinvestigationofsemi-volatileorganiccompound.Inthiswavelengthrange,p-dichlorobenzenemoleculesfirstlyabsorbedonephotontobeexcitedfromthegToundstate~1A_g(S_0)tothefirstexcitedstate1B2u($1),thenabsorbedanotherphotontobeionized.Therelationshipbetweenthesignalintensityofp-dichlorobenzenemolecularionC_6H_4~(35)Cl_2~+at248-nmwavelengthandthelaserpowerwasgiven.The1.52powerindexofC_6H_4~(35)Cl_2~+wasatypicalidentificationofthe3/2powerlaw.TherelationshipbetweentheionsignalintensityofC_6H_4~(35)Cl_2~+andthesampleconcentrationwasclosetoalinearoneintheppm(V/V)range,whichledtoadetectionlimitof125ppb(V/V)forp-dichlorobenzene.

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简介：Bythe90°elasticlightscatteringinvestigationandfarfieldobservationintherangeof20-800℃,therelationbetweenbehavioroflightscatteringanomaliesandevolutionofnanodomainstructuresinlatticeofbariumsodiumniobate(Ba_2NaNb_5O_(15),BSN)crystalwasclarified.ThecorrelationbetweenanomaliesonthetemperaturecurvesoftheelasticlightscatteringintensityandtemperaturetransformationsofnanodomainswasstudiedbyX-rayandelectronmicroscopemethods.Phasetransitionnear500℃andmovementinfieldofscatteringlightcouldbeexplainedbyappearanceofanewincommensuratephase.

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