简介:Linearsystemsarisingfromimplicittimediscretizationsandfinitedifferencespacediscretizationsofsecond-orderhyperbolicequationsonL-shapedregionareconsidered.Weanalysetheuseofdomaindeocmposilionpreconditioner.sforthesolutionoflinearsystemsviathepreconditionedconjugategradientmethod.Fortheconstant-coefficientsecond-orderhyperbolicequaionswithinitialandDirichletboundaryconditions,weprovethattheconditionnumberofthepreconditionedinterfacesystemisboundedby2+x22+0.46x2wherexisthequo-tientbetweenthelimeandspacesteps.Suchconditionnumberproducesaconvergenceralethatisindependentofgridsizeandaspectratios.Theresultscouldbeextendedtoparabolicequations.
简介:HPLC分析表明,L.rhamnosus719在MRS中发酵时,醋酸含量先升后降,而乳酸在发酵过程中不断增加,发酵过程中,乳酸和醋酸的摩尔浓度比从6h的0.28增加到60h的2.63。L.rhamnosus719在MRS培养48h的上清液抑菌效果最好,抑菌圈直径达36mm,其中乳酸、醋酸含量分别为17.70g/L和4.32g/L。L.rhamnosus719产生较高浓度的乳酸和醋酸是其抑菌作用的主要原因。
简介:易损斑块的破裂是急性心血管事件发生的罪魁祸首,CD40-CD40L系统作为免疫和炎症反应的枢纽,其贯穿急性冠脉综合症(ACS)发生发展至斑块破裂及血栓形成的全过程,阻断其信号传导途径可起到一定的预防效果,提示在临床上可作为一种新的治疗途径。
简介:LetL~2([0,1],x)bethespaceoftherealvalued,measurable,squaresummablefunctionson[0,1]withweightx,andlet■_nbethesubspaceofL~2([0,1],x)definedbyalinearcombinationofJ_0(μ_kx),whereJ_0istheBesselfunctionoforder0and{μ_k}isthestrictlyincreasingsequenceofallpositivezerosofJ_0.Forf∈L~2([0,1],x),letE(f,■_n)betheerrorofthebestL~2([0,1],x),i.e.,approximationoffbyelementsof■_n.Theshiftoperatoroffatpointx∈[0,1]withstept∈[0,1]isdefinedbyT(t)f(x)=(1/π)∫_0~πf((x~2+t~2-2xtcosθ)~(1/2))dθ.Thedifferences(1-T(t))~(r/2)f=∑_(j=0)~∞(-1)~j(_j~(r/2))T~j(t)foforderr∈(0,∞)andtheL~2([0,1],x)-modulusofcontinuityω_r(f,τ)=sup{||(I-T(t))~(r/2)f||:0≤t≤τ}oforderraredefinedinthestandardway,whereT~0(t)=Iistheidentityoperator.Inthispaper,weestablishthesharpJacksoninequalitybetweenE(f,■_n)andω_r(f,τ)forsomecasesofrandτ.Moreprecisely,wewillfindthesmallestconstant■_n(τ,r)whichdependsonlyonn,r,andτ,suchthattheinequalityE(f,■_n)≤■_n(τ,r)ω_r(f,τ)isvalid.