简介：Onenewsesquiterpenecompound,namely,illihenlactoneA（1）,andonenewprenylatedC6–C3compound,illihenryioneH（2）,alongwiththreeknownsesquiterpenes（3–5）wereisolatedfromthestemsofIlliciumhenryi.Thestructuresof1and2wereelucidatedbyspectroscopicevidenceincludingNMR,HRESIMSandcirculardichroism（CD）.Compound2exhibitedaweakinhibitoryratioforbglucuronidasereleaseinducedbyplatelet-activatingfactor（PAF）inratpolymorphonuclearleukocytes（PMNs）invitro.

简介：Inthispaper,weintroduceaconditionweakerthantheLpdifferentiability,whichwecallCpcondition.Weprovethatifafunctionsatisfiesthisconditionatapoint,thenthereexiststhebestlocalapproximationatthatpoint.WealsogiveanecessaryandsufficientconditionforthatafunctionbeLpdifferentiable.Inaddition,westudytheconvexityofthesetofclusterpointsofthenetofbestappoximationsoff,{Pe(f)}ase→0.

简介：Inthispaper,weapplythecontractionmappingtheoremtoestablishsomeboundedandunboundedadditiveperturbationtheoremsconcerninglocalC-semigroups.SomegrowthconditionsofperturbationsoflocalC-semigroupsarealsoestablished.

简介：ThefirststarsintheearlyUniversewereformedabout400millionyearsafterthebigbang.VerificationoftheexistenceofthesestarsisimportantforourunderstandingoftheevolutionoftheUniverse[1].IthasbeenpredictedthatforPopulation-IIIstellarproductionyields,theabundancesofodd-Zelementsareremarkablydeficientcomparedtotheiradjacenteven-Zelements[2].Astronomersaresearchingforlong-lived,lowmassstarswiththeuniquenucleosyntheticpatternmatchingthepredictedyields[3].

简介：

简介：TheeffectofacidcomponentincludingvariousconventionalacidsandtungsticcompoundsonglucosehydrogenationoveraseriesofbinarycatalystsystemcontainingRu/Ccatalystwasinvestigated.TheresultsshowedthatHCl,H2SO4,H3BO3,H3PO4,andHNO3hadnegligibleeffect,whileallthetungsticcompoundsimposedinhibitingeffectsonthehydrogenationofglucoseoverRu/Ccatalyst,andthesuppressingeffectfollowedtheorderofH2WO4>HPW>WO3>AMT>HSiW.Thisorderisthesameastheorderofethyleneglycol(EG)yieldsintheone-potconversionofglucosetoEG,suggestingtheimportantroleofcompetitionbetweenglucosehydrogenationandretro-aldolcondensationincontrollingtheselectivityofEG.

简介：

简介：纸的目的是估计Wasserstein测量的密度功能或分发功能公制的，统计距离的一种典型类型，它通常在统计学习被要求。基于古典伯恩斯坦近似，一个计划被介绍。得到计划的错误估计，到为单调C1功能估计伯恩斯坦近似的L1标准的问题拐弯，它是很少在古典近似理论讨论了。最后，我们由统计距离得到概率估计。

简介：

简介：在B3LYP/6-311＋G（3df,2p）水平上对HS和HOO反应中的所有物种进行了几何构型优化和频率计算,采用QCISD（T）/6-311＋G（3df,2p）方法获得了各物种的单点能,构建了HS和HOO反应在单、三重态势能剖面.结果表明,HS与HOO反应体系中存在2种不同的抽氢通道,在单、三重态势能面上生成的产物分别为[1P1（H2O2＋1S）,1P2（H2S＋1O2）]和[3P1（H2O2＋3S）,3P2（H2S＋3O2）].标题反应主要发生在三重态势能面上,优势通道[R→3TS2→3P2（H2S＋3O2）]的活化能为9.99kJ·mol-1.此结果对认识大气硫迁移转变规律具有实际意义.

简介：Inthispaper,weintroducegeneralizedcyclicC-contractionsthroughpnumberofsubsetsofaprobabilisticmetricspaceandestablishtwofixedpointresultsforsuchcontractions.InourfirsttheoremweusetheHadzictypet-norm.InournexttheoremweuseLukasiewiczt-norm.OurresultsgeneralizetheresultsofChoudhuryandBhandari[11].Acontrolfunction[3]hasbeenutilizedinoursecondtheorem.Theresultsareillustratedwithsomeexamples.

简介：Arylhalidesareakindofextremelyvaluablecompoundsusedintransition-metal-catalyzedcouplingreactions,aswellasimportantstructuremotifsinmanynaturalproductsandmanufactureddrugs[1,2].Theclassicalapproachforpreparationofhaloarenesiselectrophilicaromaticsubstitution(EAS)usingvarioushalogenatingreagentsoroxidativehalogenationswithhalogenatingreagentgeneratedinsitufromhalidesandoxidants,suchasperoxide,oxygenandmeta-cholorperoxybenzoicacid(mCPBA)[3,4].However,harshreactionconditionsarerequiredforhalogenationoflessactivearomatics.orthoMetalationfollowedbyhalogenquenchingisanotherapproachforhalogenationofaromatics[5].However,thereareobviousdrawbacksforthesemethods,suchaslowregioselectivity,harshconditionsandevendangerousprocedures.Therefore,thedevelopmentofanalternativeandpracticalwayremainschallengeinorganicsynthesis.

简介：Toeffectivelysolvetheagglomerationproblemsinthesolidstatereactionprocess,pre-addingglucoseisadoptedtothesynthesisofLiFePO4/CenergymaterialsusingFe–Pwasteslag.Theaverageparticle&grainsizeofLiFePO4/Cdecreases,andtheimpuritiesinLiFePO4/Ccompositesreducetoagreatextent.Itmakesgreatsensetothemassindustrialproduction.Theoptimumsynthesisconditionsdeterminedinthisworkarebasedontheorthogonalexperiments.Thesamplessynthesizedinascaleof500gexhibithighpurity,excellentelectrochemicalperformance,highreactionactivity,goodreversibility,andlowpolarizationlevel.Thedischargecapacitiesare145,134,117,and102mAh/gatthecurrentdensitiesof0.1C,0.2C,0.5Cand1C,respectively.ThisworkputsforwardapracticalsuggestionformassproducingenvironmentalbenignandlowcostLiFePO4/Cascathodematerialsoflithiumionbatteries.

简介：若无限长均匀带电直导线（线电荷）与接地平板系统的电场是二维静电场,当求解区域可视为为多边形时,则可应用S-C映射法和电像法为统一模型,求解出线电荷在求解区域所激发的电势。

简介：Theroleofpulseparametersonnanoparticlepropertyisinvestigatedself-consistentlybasedonacoupleoffluidmodelandaerosoldynamicsmodelinacapacitivelycoupledparallel-plateacetylene(C2H2)discharge.Inthismodel,themasscontinuityequation,momentumbalanceequation,andenergybalanceequationforneutralgasaretakenintoaccount.Thus,thethermophoreticforceariseswhenagastemperaturegradientexists.Thetypicalresultsofthismodelarepositiveandnegativeiondensities,electronimpactcollisionsrates,nanoparticledensity,andchargedistributions.Thesimulationisperformedfordutyratio0.4/0.7/1.0,aswellaspulsemodulationfrequencyfrom40kHzto2.7MHzforpureC2H2dischargesatapressureof500mTorr.Wefindthatthepulseparameters,especiallythedutyratio,haveagreataffectonthedissociativeattachmentcoefficientandthenegativedensity.Moreimportantly,bydecreasingthedutyratio,nanoparticlesstarttodiffusetothewall.Undertheactionofgasflow,nanoparticledensitypeakiscreatedinfrontofthepulseelectrode,wherethegastemperatureissmaller.

简介：本文讨论矩阵方程ATX＋xTA=C的一般解及其最佳逼近解的正交投影迭代解法．首先，利用矩阵的结构特点及相关性质，并借助矩阵空间的相关理论，给出求该矩阵方程一般解正交投影迭代算法；其次，根据奇异值分解、F-范数正交变换不变性证明算法的收敛性并推导出算法的收敛速率估计式，当方程相容时，该算法收敛于问题的极小范数解，且对该算法稍加修改，就可得到相应最佳逼近解；最后，用数值实例验证算法的有效性．

简介：本文证明第二种服务可选的M/M/1排队模型的主算子的点谱包含一个区间（-α,0）,α〉0.此结果表明该主算子生成的C_0-半群不是紧算子,甚至不是最终紧算子.本文的结果与我们以前的结果合并后得到：（i）该C_0-半群的本质增长界为0.从而,该C_0-半群不是拟紧算子.（ii）该模型的时间依赖解不可能指数收敛于其稳态解.（iii）该C_0-半群的本质谱半径等于1.

简介：Theoreticalmodelsofstellarevolutionpredictnegligiblequantitiesof6Li,9Be,and11Binthehydrogenburningphasesofastar’sevolution[1].TheprimordialBig-Bangnucleosynthesis(BBN)modelmightbemoregenerousinitsproductionoftheseelements[2].Theradiative-capturecrosssectionforprotoncaptureon11Bleadingto12CissmallatastrophysicallyinterestingenergiesbecauseofthelargeCoulombbarrier.

简介：

简介：Pt/WO3/CnanocompositeswithparallelWO3nanorodsweresynthesizedandappliedasthecathodecatalystforprotonexchangemembranefuelcells(PEMFCs).Electrochemicalresultsandsinglecelltestsshowthatanenhancedactivityfortheoxygenreductionreaction(ORR)isobtainedforthePt/WO3/CcatalystcomparedwithPt/C.ThehighercatalyticactivitymightbeascribedtotheimprovedPtdispersionwithsmallerparticlesizes.ThePt/WO3/Ccatalystalsoexhibitsagoodelectrochemicalstabilityunderpotentialcycling.Thus,thePt/WO3/CcatalystcanbeusedasapotentialPEMFCcathodecatalyst.