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343 个结果
  • 简介:维生E作为聚烯烃主抗氧剂的应用可以说是20世纪90年代聚合物稳定化领域的一个重要成果。维生E的有效成分为a-生育酚(ATP),ATP不仅显示极高的抗氧活性,而且可以消除或降低塑料包装材料内的异味,因此塑料包装业特别是食品和医药的生产厂商对此表现出极大兴趣。

  • 标签: 维生素E 抗氧剂 塑料包装材料 有效成分 抗氧活性 生产厂商
  • 简介:水溶性的维生C是一种人体必需的营养物质.维生C是含有烯二醇基的多羟基内酯结构,利用其水溶液在波长265nm处有较强烈的紫外吸收峰,建立了直接用紫外分光光度法测定新鲜蔬菜中维生C含量的方法.实验结果表明,维生C的含量在1.0~12.0μg/mL内线性关系良好,线性方程为A=0.06603c+0.01974(R2=0.99751),检出限为0.044μg/mL,样品加标回收率为97.5%~105.4%.方法操作简单,准确度高,对新鲜蔬菜的测定结果令人满意.

  • 标签: 新鲜蔬菜 维生素C 紫外分光光度法
  • 简介:用HNO3-HClO4混酸溶解养生堂维生C片,用电感耦合等离子体质谱法测定其中的无机元素,实验表明养生堂维C中Fe,Na,Ca,Mg,K,Zn和Cu的含量较为丰富。方法灵敏可靠,测量相对标准偏差〈3.3%,回收率在99.5oA~103.6%,实验结果为探讨养生堂维生C对人体的保健作用提供了参考数据。

  • 标签: 电感耦合等离子体质谱法 维生素C 无机元素
  • 简介:引进分次Armendariz环的概念,讨论了分次环R=n∈ZRn及由它导出的非分次环R,R0,及R[x]之间关于Armendariz环性质的关系,并推广了[8]的结论,得到在R=n∈ZRn是Z-型正分次环的前提下,若R是分次Armendariz,分次正规环,则R是P.P.环(Baer环)当且仅当R是分次P.P.环(分次Baer环).

  • 标签: 分次Armendariz环 分次P.P.环 分次Baer环 分次正规环
  • 简介:在Г-环中定义P-根,次P-根与拟P-根的概念,讨论它们的性质及相互间的关系.给出了次P-根的构造,证明了对Г-环的任一代数性质P,总可确定两个Amitsur-Kurosh根.同时,对Г-环的几个具体根的研究做了统一.拓广了Г-环根理论的研究领域.

  • 标签: 拓广 代数性质 证明 构造 具体 研究领域
  • 简介:Multimediastreamingservedthroughpeer-to-peer(P2P)networksisboomingnowadays.However,theend-to-endstreamingqualityisgenerallyunstableduetothevariabilityofthestateofserve-peers.Ontheotherhand,proxycachingisabandwidth-efficientschemeforstreamingovertheInternet,whereasitisasubstantiallyexpensivemethodneedingdedicatedpowerfulproxyservers.Inthispaper,wepresentaP2PcooperativestreamingarchitecturecombinedwiththeadvantagesofbothP2Pnetworksandmultimediaproxycachingtechniquestoimprovethestreamingqualityofparticipatingclients.Inthisframe-work,aclientwillsimultaneouslyretrievecontentsfromtheserverandotherpeersthathaveviewedandcachedthesametitlebefore.Inthemeantime,theclientwillalsoselectivelycachetheaggregatedvideocontentsoastoservestillfutureclients.Theassociateprotocoltofacilitatethemulti-pathstreamingandadistributedutility-basedpartialcachingschemearedetailedlydis-cussed.Wedemonstratetheeffectivenessofthisproposedarchitecturethroughextensivesimulationexperimentsonlarge,Inter-net-liketopologies.

  • 标签: 分布式高速缓存 P2P网络 流媒体服务 体系结构
  • 简介:SomecharacterizationsoftheconditionalexpectationoperatorsonLebesgue-BochnerspacesL_p(μ,X)aregiven,where1≤p<∞,p≠2.AlsoanexampleisgiventoshowthatthecharacterizationsoftheconditionalexpectationoperatorsonL_p(μ,X)aredifferentfromthatonL_p(μ)_zFinally,arepresentationoftheconstant-preservingcontractiveprojectiononspacesL_p(μ,X)isgotwhen0<p<1.

  • 标签: preserving EXPECTATION OPERATORS Radon CONDITIONAL LEBESGUE
  • 简介:ONTHECLASSφ_~*(α,β,γ,ε,η;A)ofp-VALENTFUNCTIONSWITHREFERENCETOTHEBERNARDIINTEGRALOPERATORJianMing(蹇明)(WuhanUniversity,Wuhan430...

  • 标签: CLASS OPERATOR THEBERNARDI ON FUNCTIONS INTEGRAL
  • 简介:<正>LetD={z∈:|z|<1}andφbeanormalfunctionon[0,1).Forp∈(0,1)suchafunctionφisusedtodefineaBergmanspaceA~p(φ)onDwithweightφ~p(|·|)/(1-|·|~2).Inthispaper,thedualspaceofA~p(φ)isgiven,fourcharacteristicsofCarlesonmeasureonA~p(φ)areobtained.Moreover,asanapplication,threesequenceinterpolationtheoremsinA~p(φ)arederived.

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  • 简介:Letp(z)=beapolynomialdegreenandletThenaccord-ingtoBernstein’sinequality||p’||p||.ItisawellknownopenproblemtoobtaininequalityanalogoustoBernstein’sinequalityfortheclassIInofpolynomialssatisfyingp(z)≡znp(1/z)HereweobtainaninequalityanalogoustoBernstein’sinequalityforasubclassofIInOurresultsincludeseveraloftheknownresultsasspecialcases.

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  • 简介:当branes的二栈是到对方的没放的平行时,我们概括在branes的二平行的栈之间的远程的相互作用的计算到各种各样的案例。我们分类相互作用的性质(排斥或吸引人)为每个专辑,大小写和这个分类能被用来认为在象brane界限状态那样的二个复杂brane系统之间的远程的相互作用的性质正当。我们将在这份报纸提供明确的例子表明这。

  • 标签: 相互作用 长距离 分类 堆栈 吸引力 排斥力
  • 简介:InthispaperwestudytheconvergencenfaclassofmeansonHp(G)(0<p<1),themeanstaketheBochner-Rieszmeansin[1],thegeneralizedBochner-Rieszmeansin[2],andtheoperatorsTΦrin[3]asspecialcases.Weobtainweak-typeestimatesfortheassociatedmaximaloperatorsandthemaximalmeanboundednessforthemeans.

  • 标签: operators maximal RIESZ CLASS estimates singular
  • 简介:P2Psystemsarecategorizedintotree-basedandmesh-basedsystemsaccordingtotheirtopologies.Mesh-basedsystemsareconsideredmoresuitableforlarge-scaleInternetapplications,butrequireoptimizationonlatencyissue.Thispaperproposesacontentsubscribingmechanism(CSM)toeliminateunnecessarytimedelaysduringdatarelaying.Anodecansendcontentdatatoitsneighborsassoonasitreceivesthedatasegment.Noadditionaltimeistakenduringtheinteractivestagespriortodatasegmenttransmissionofstreamingcontent.CSMconsistsofthreesteps.First,everynoderecordsitshistoricalsegmentslatency,andadoptsgammadistribution,whichpossessespowerfulexpressionability,toexpresslatencystatistics.Second,anodepredictssubscribingsuccessratioofeveryneighborbycomparingthegammadistributionparametersofthenodeanditsneighborsbeforeselectinganeighbornodetosubscribeadatasegment.Theabovestepswouldnotincreaselatencyastheyareexecutedbeforethedatasegmentsarereadyattheneighbornodes.Finally,thenode,whichwassubscribedto,sendsthesubscribeddatasegmenttothesubscriberimmediatelywhenithasthedatasegment.ExperimentsshowthatCSMsignificantlyreducesthecontentdatatransmissionlatency.

  • 标签: 国际互联网 分布特点 流动特点 P2P技术
  • 简介:ThespectrumoftheΣ(1193)excitedstates,Σ,withisospinI=1andstrangenessS=??1isoneofthemostimportantissuesinhadronicphysics.TheΣresonancesaremostlyproducedandstudiedinK-inducedreactions.ManyΣresonancesarenowcatalogedbytheParticleDataGroup[1].However,ourknowledgeoftheseresonancesisstillverypoor.Intheenergyregionbelow2GeV,onlyafewofthemarewellestablished,suchastheΣ(1385)ofspin-parityJP=3=2+,Σ(1670)ofJp=3=2??andΣ(1775)ofJp=5=2??.Theothersarenotwellestablishedandsomeofthemareevenoflargeuncertaintiesontheirexistence.Thus,thestudyoftheΣresonancewiththeavailableexperimentaldataisnecessary.

  • 标签: EXPERIMENTAL Π now OUR is
  • 简介:FIRSTORDERQUASILINEAREQUATIONSINSEVERALINDEPENDENTVARIABLESWITHSINGULARINITIALDATAL~(P<∞)¥(赵会江)ZhaoHuijiang(YoungScientistLa?..

  • 标签: SINGULAR INITIAL DATA QUASILINEAR EQUATIONS global
  • 简介:p-ω-低亚硫酸钠正常操作员的近似的点光谱性质被给并且证明。事实上,它是ω-低亚硫酸钠正常操作员的近似的点光谱性质的归纳。系列的关系和p-ω-低亚硫酸钠正常操作员的数字范围被获得。为p-ω-低亚硫酸钠正常操作员T,在另一方面,如果T是正常的,那么,T也是正常的,这被显示出。

  • 标签: 亚正规算子 近似点谱 值域 HILBERT空间 线性算子