简介:TheMoS2catalystswerepreparedfromvariousmolybdateprecursorsincludinginorganicandorganicmolybdatecompounds.ThesulfidationdegreeandmorphologyofactivephasesofMoS2activatedbyvariousmolybdateprecursorsinH2S/H2streamatdifferenttemperatureswerestudiedbyX-rayphotoelectronspectroscopy(XPS)andhigh-resolutiontransmissionelectronmicroscopy(HRTEM).TheorganicmolybdateprecursorsleadtoMoS2catalystswithhighersulfidationdegreeandsmalleractivephasestodemonstratehighercatalyticactivityduringhydrodesulfurizaiton(HDS)of4,6-DMDBT.
简介:WediscussthenonlinearSchrdingerequationwithvariablecoefficientsin2Dgraded-indexwaveguideswithdifferentdistributedtransversediffractionsandobtainexactbrightanddarksolitonsolutions.Basedonthesesolutions,wemainlyinvestigatethedynamicalbehaviorsofsolitonsinthreedifferentdiffractiondecreasingwaveguideswiththehyperbolic,GaussianandLogarithmicprofiles.Resultsindicatethatforthesameparameters,theamplitudeofbrightsolitonsintheLogarithmicprofileandtheamplitudeofdarksolitonsintheGaussianprofilearebiggestrespectively,andtheamplitudeinthehyperbolicprofileissmallest,whilethewidthofsolitonshastheoppositecase.
简介:[背景]红火蚁入侵可能对土著生物产生各种各样的影响,而其入侵对农作物的影响是值得研究的,可为准确评估该蚁的经济危害性提供依据。[方法]通过室内模拟建巢和大田迁移蚁巢试验研究了红火蚁对玉米及绿豆种子萌发的影响。[结果]红火蚁室内种群对玉米及绿豆种子有啃咬破坏作用,但对萌发无影响。大田红火蚁种群显著抑制了玉米、绿豆种子萌发,高密度区域对玉米未正常萌发的种子数增加了2.86倍;高、低密度区域绿豆未正常萌发的种子数分别增加了1.21和0.98倍。[结论与意义]红火蚁入侵旱地生境后对玉米及绿豆种子萌发具有明显负面作用,将会直接导致农业生产损失。研究结果可为了解红火蚁入侵对农作物的影响提供参考。
简介:Anovelhydrophilicnanocompositeadditive(TiO2-g-PNIPAAm)wassynthesizedbythesurfacemodificationoftitaniumdioxide(TiO2)withN-isopropylacrylamide(NIPAAm)via"graft-from"technique.Andthenanocompositemembraneofpoly(vinylidenefluoride)(PVDF)/TiO2-g-PNIPAAmwasfabricatedbywetphaseinversion.Thegraftdegreewasobtainedbythermo-gravimetricanalysis(TGA).Fouriertransforminfraredattenuatedreflectionspectroscopy(FTIR-ATR)andX-rayphotoelectronicspectroscopy(XPS)characterizationresultssuggestedthatTiO2-g-PNIPAAmnanoparticlessegregatedonmembranesurfaceduringthephaseseparationprocess.Scanningelectronmicroscopy(SEM)wasconductedtoinvestigatethesurfaceandcross-sectionofthemodifiedmembranes.ThewatercontactanglemeasurementsconfirmedthatTiO2-g-PNIPAAmnanoparticlesendowedPVDFmembranesbetterhydrophlilicityandthermo-responsivepropertiescomparedwiththoseofthepristinePVDFmembrane.Thewatercontactangledecreasedfrom92.8°ofthePVDFmembraneto61.2°ofthenanocompostiemembrane.Bovineserumalbumin(BSA)staticanddynamicadsorptionexperimentssuggestedthatexcellentantifoulingpropertiesofmembraneswasacquiredafteraddingTiO2-gPNIPAAm.ThemaximumBSAadsorptionat40°Cwasabout3timesthanthatat23°C.ThepermeationexperimentsindicatedthewaterfluxrecoverratioandBSArejectionratiowereimprovedatdifferenttemperatures.
简介:目的比较空腹血浆血糖(FPG)、糖化血红蛋白(HbA1c)、2型糖尿病(T2DM)危险评分表(DRS)、T2DM发病概率预测模型(DPM)筛查无症状2型糖尿病患者的效果。方法使用2010年浙江省参与中国慢性病监测的横断面调查资料,利用受试者特征工作曲线(ROC)对上述4种方法筛查无症状T2DM的灵敏度、特异度、ROC曲线下面积(AUROC)进行分析,并对筛查成本进行比较。结果FPG筛查无症状T2DM的灵敏度、特异度、AUROC和平均发现每例糖尿病的筛查成本分别为79.11%、90.46%、0.904和295元;HbA1c为75.32%、84.40%、0.862和891元;DRS为77.85%、91.45%、0.897和804元;DPM为82.28%、79.95%、0.876和789元。结论FPG筛查无症状T2DM筛查效果最好,筛查成本最低,且易于操作,是适合社区日常开展糖尿病筛查的方法。
简介:Alzheimer’sdisease(AD)isoneofthemostdevastatingdiseasesaffectingthelifeandhealthofagingpopulation.TwohallmarksofADaresenileplaquesandneurofibrillarytangles,andADiswellknownforthemassivelossofneuronsandimpairedcognitivefunctionsespeciallymemoryloss.Despiteextensivesearchforeffectivetreatment,available
简介:Sn-dopedTiO_2nanoparticleswithhighsurfaceareaof125.7m~2·g~(-1)aresynthesizedviaasimpleone-stephydrothermaimethodandexploredasthecathodecatalystsupportforprotonexchangemembranefuelcells.ThesynthesizedsupportmaterialsarestudiedbyX-raydiffractionanalysis,energydispersiveX-rayspectroscopyandtransmissionelectronmicroscopy.Itisfoundthattheconductivityhasbeengreatlyimprovedbytheadditionof30mol%SnandPtnanoparticlesarewelldispersedonTi_(0.7)Sn_(0.3)O_2supportwithanaveragesizeof2.44run.ElectrochemicalstudiesshowthattheTi_(0.7)Sn_(0.3)O_2nanoparticleshaveexcellentelectrochemicalstabilityunderahighpotentialcomparedtoVulcanXC-72.Theas-synthesizedPt/Ti_(0.7)Sn_(0.3)O_2exhibitshighandstableelectrocatalyticactivityfortheoxygenreductionreaction.ThePt/Ti_(0.7)Sn_(0.3)O_2catalystreservesmostofitselectrochemicallyactivesurfacearea(ECA),anditshalfwavepotentialdifferenceis11mV,whichislowerthanthatofPt/XC-72(36mV)under10hpotentialholdat1.4Vvs.NHE.Inaddition,theECAdegradationofPt/Ti_(0.7)Sn_(0.3)O_2is1.9timeslowerthancommercialPt/XC-72under500potentialcyclesbetween0.6Vand1.2Vvs.NHE.Therefore,theassynthesizedPt/Ti_(0.7)Sn_(0.3)O_2canbeconsideredasapromisingalternativecathode,catalystforprotonexchangemembranefuelcells.