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65 个结果
  • 简介:这份报纸与随机的系数为随机的系统涉及混合H2/H控制,它实际上是把H2优化与H2/H的名字揭示的H柔韧的性能相结合的控制。基于古典理论线性二次(LQ短)最佳的控制,为不定的向后的随机的Riccati方程的答案的存在和唯一的足够、必要的条件(BSRE,为短)把坚韧性与H联系了被导出。然后,为H2/H控制的存在的足够、必要的条件被给利用一双联合随机的Riccati方程。

  • 标签: 随机系数 控制相 H2 充分必要条件 鲁棒性能 随机系统
  • 简介:我们使用Ringel大厅代数学途径为在Xi被描绘的类型B2的量组学习正规基础元素[12]。然而,我们的途径在那里简化几计算。

  • 标签: 量子群 RINGEL-HALL代数 2型 典范基
  • 简介:DrivenbycuriosityaboutpossibleflightoptionsfortheChang’e-2spacecraftafteritremainsattheSun-EarthL2point,effectiveapproachesweredevelopedfordesigningpreliminaryfuel-optimalnear-Earthasteroidflybytrajectories.Theapproachesincludetheuseofmodifiedunstablemanifolds,gridsearchofthemanifolds’parameters,andatwo-impulsemaneuverfororbitalphasematchingandz-axisbiaschange,andaredemonstratedtobeeffectiveinasteroidtargetscreeningandtrajectoryoptimization.Asteroidflybysareexpectedtobewithinadistanceof2×107kmfromtheEarthowingtotheconstrainedEarth-spacecraftcommunicationrange.Inthiscase,thespacecraft’sorbitalmotionissignificantlyaffectedbythegravitiesofboththeSunandtheEarth,andtherefore,theconceptofthe"heliocentricoscillating-Keplerorbit"isproposed,becausetheclassicalorbitalelementsoftheflybytrajectoriesreferencedintheheliocentricinertialframeoscillatesignificantlywithrespecttotime.Theanalysisandresultspresentedinthisstudyshowthat,amongtheasteroidswhoseorbitsarethemostaccuratelypredicted,"Toutatis","2005NZ6",or"2010CL19"mightbeencounteredbyChang’e-2inlate2012or2013withtotalimpulseslessthan100m/s.

  • 标签: 近地小行星 飞行轨迹 地球 太阳 轨道运动 不稳定流形
  • 简介:一系列5-phenyl-3H-spiro[indoline-3,2-[1,3,4]thiadiazol]-2-one类似物被综合并且他们的Bcl-2蛋白质禁止的活动被学习。铅混合物原来用荧光被识别基于极化的竞争有约束力的试金。在调查的10混合物之中,1k分别地显示出好有约束力的亲密关系到Bcl-xL和Mcl-1,与8.9mol/L和3.4mol/L的抑制常数。当复合1c完成了紧密的有约束力的亲密关系到Bcl-xL时(Ki=0.16mol/L),有潜力是新铅混合物。

  • 标签: 类似物 生物学评价 合成 苯基 吲哚 二氢
  • 简介:HydrotalciteprecursorsofLamodifiedNi-Al2O3andNi-SiO2catalystspreparedbyco-precipitationmethodandthecatalyticactivitieswereexaminedfortheproductionofCOx-freeH2byCH4decomposition.Physico-chemicalcharacteristicsoffresh,reducedandusedcatalystswereevaluatedbyXRD,TPRandO2pulsechemisorptions,TEMandBET-SAtechniques.XRDstudiesshowedphasesduetohydrotalcite-likeprecursorsinovendriedformproduceddispersedNiOspeciesuponcalcinationinstaticairabove450C.Ramanspectraofdeactivatedsamplesrevealedthepresenceofbothorderedanddisorderedformsofcarbon.Ni-La-Al2O3catalystwithamoleratioofNi:La:Al=2:0.1:0.9exhibitedtremendouslyhighlongevitywithahydrogenproductionrateof1300molH2mol1Ni.AdirectrelationshipbetweenNimetalsurfaceareaandhydrogenyieldswasestablished.

  • 标签: CH4 decomposition Ni-La-Al HYDROTALCITE NI metal
  • 简介:在这份报纸,为在3D的不可压缩的海军司烧方程围住的nonhomogeneous或无界的领域的大答案的全球L2稳定性的问题被学习。由精细的精力估计并且在大解决方案的合适的条件下面,它证明如果起始的数据是已知的强壮的解决方案的那些上的小不安,大解决方案是稳定的。

  • 标签: 不可压缩NAVIER-STOKES方程 稳定性 非齐次 能量估计 无界域 非均匀
  • 简介:Novelsulfur-containingcompounds(3a–3c,4a–4c)wereobtainedinethanolwith1,3-diphenyl-2-propanoneasthestartingmaterial.Theadvantagesofthisprocedureweremildreactionconditions,simpleprotocol,andhighyields.ThestructuresoftheproductswerecharacterizedbyIR,1HNMR,MSandelementaryanalysis.Thecrystalofthenewcompound4abelongstomonoclinic,spacegroupC2witha=18.727(3),b=6.5179(9),c=13.7576(18),b=131.0610(10)°,V=1266.2(3)A3,Z=2,Dc=2.136g/cm3,μ=1.078mm-1,F(000)=843,R=0.0490andwR=0.1247for3211observedreflectionwithI>2δ(I).X-rayanalysisrevealsthatthemoleculeisnotsymmetrical,themolecularstructureisstabilizedbyweakp–pstackinginteractions,andnoclassicalhydrogenbondscanbeobserved.

  • 标签: 硫醇 苄基 显示 合成 寺院 结构稳定
  • 简介:Threepairsofnovel2-aryl-3,4,5-trihydroxypiperidines(6–8andtheirenantiomers),thepiperidineanaloguesofthepyrrolidinealkaloidsradicamineAandradicamineB,werepreparedfromsixmemberedcyclicnitronesthroughaconcisetwo-stepprocedure,i.e.,Grignardreagentadditionanddeprotection.Thesenovelpolyhydroxylatedpiperidineiminosugarswereassayedagainst10typesofenzymes.Onlycompound8exhibitedweakinhibition(IC501080mmol/L)againstb-galactosidasefromratintestinallactases.

  • 标签: 半乳糖苷酶 酶抑制 芳基 合成 格氏试剂 IC50
  • 简介:Anewcytotoxicpyrrolidinoindolinediketopiperazinedimer,cristatuminE(1),wasisolatedfromthefermentationbrothofthealgalfungusEurotiumherbariorumHT-2associatedwiththemarinealgae,Enteromorphaprolifera.ThestructurewasdeterminedbyspectroscopicanalysesandMarfey’saminoacidanalysis.CristatuminE(1)showedcytotoxicityagainstK562tumorcelllineandantibacterialactivityagainstEnterobacteraerogenesandEscherichiacoliwithIC50andMICvaluesof8.3,44.0and44.0mmol/L,respectively.

  • 标签: 细胞毒性 散囊菌 二聚体 藻菌 哌嗪 二酮
  • 简介:Thispaperpresentsanovelmechanicalattachment,i.e.,nonlinearenergysink(NES),forsuppressingthelimitcycleoscillation(LCO)ofanairfoil.Thedynamicresponsesofatwo-degree-of-freedom(2-DOF)airfoilcoupledwithanNESarestudiedwiththeharmonicbalancemethod.DiferentstructureparametersoftheNES,i.e.,massratiobetweentheNESandairfoil,NESofset,NESdamping,andnonlinearstifnessintheNES,arechosenforstudyingtheefectoftheLCOsuppressiononanaeroelasticsystemwithasupercriticalHopfbifurcationorsubcriticalHopfbifurcation,respectively.TheresultsshowthatthestructuralparametersoftheNEShavediferentinfluenceonthesupercriticalHopfbifurcationsystemandthesubcriticalHopfbifurcationsystem.

  • 标签: 非线性能 2自由度 振荡抑制 极限周期 机翼 量水槽
  • 简介:图G的A2-dominating集合是G的顶点的集合D以便V(G)的每个顶点|D在D有至少二位邻居。图G的一个全部的外部独立人士的统治集合是G的顶点的集合D以便G的每个顶点在D,和集合V(G)有一位邻居|D是独立的。2支配(全部的外部独立人士的支配,分别地)图G的数字是2-dominating的最小的集的势(全部的外部独立人士的统治,分别地)G的集合。我们调查在2支配和树的全部的外部独立人士的支配数字之间的比率。

  • 标签: 控制数 比例 独立控制 支配集 顶点 曲线图
  • 简介:Recentadvancesontheuseofnanocarbon-basedelectrodesfortheelectrocatalyticconversionofgaseousstreamsofCO2toliquidfuelsarediscussedinthisperspectivepaper.Anovelgas-phaseelectrocatalyticcell,differentfromthetypicalelectrochemicalsystemsworkinginliquidphase,wasdeveloped.Thereareseveraladvantagestoworkingasphase,e.g.noneedtorecovertheproductsfromaliquidphaseandnoproblemsofCO2solubility,etc.Operatingundertheseconditionsandusingelectrodesbasedonmetalnanoparticlessupportedovercarbonnanotube(CNT)typematerials,longC-chainproducts(inparticularisopropanolunderoptimizedconditions,butalsohydrocarbonsuptoC8-C9)wereobtainedfromthereductionofCO2.Pt-CNTaremorestableandgiveinsomecasesahigherproductivity,butFe-CNT,particularusingN-dopedcarbonnanotubes,giveexcellentpropertiesandarepreferabletonoble-metal-basedelectrocatalystsforthelowercost.ThecontrolofthelocalizationofmetalparticlesattheinneroroutersurfaceofCNTisanimportactfactorfortheproductdistribution.ThenatureofthenanocarbonsubstratealsoplaysarelevantroleinenhancingtheproductivityandtuningtheselectivitytowardslongC-chainproducts.TheelectrodesfortheelectrocatalyticconversionofCO2arepartofaphotoelectrocatalytic(PEC)solarcellconcept,aimedtodevelopknowledgeforthenewgenerationartificialleaf-typesolarcellswhichcanusesunlightandwatertoconvertCO2tofuelsandchemicals.TheCO2reductiontoliquidfuelsbysolarenergyisagoodattempttointroducerenewablesintotheexistingenergyandchemicalinfrastructures,havingahigherenergydensityandeasiertransport/storagethanothercompetingsolutions(i.e.H2).

  • 标签: 液体燃料 催化转化 纳米碳 碳电极 二氧化碳排放量 CO2