简介:Theoreticalmodelsofstellarevolutionpredictnegligiblequantitiesof6Li,9Be,and11Binthehydrogenburningphasesofastar’sevolution[1].TheprimordialBig-Bangnucleosynthesis(BBN)modelmightbemoregenerousinitsproductionoftheseelements[2].Theradiative-capturecrosssectionforprotoncaptureon11Bleadingto12CissmallatastrophysicallyinterestingenergiesbecauseofthelargeCoulombbarrier.
简介:Theresultsonadissociationbehaviorofpropanehydratespreparedfrom'drywater'andcontainedunreactedresidualwaterintheformoficeinclusionsorsupercooledliquidwater(watersolutionofgas)werepresentedfortemperaturesbelow273K.Thetemperaturerampingorpressurereleasemethodwasusedforthedissociationofpropanehydratesamples.Itwasfoundthatthemechanismofgashydratedissociationattemperaturesbelow273Kdependedonthephasestateofunreactedwaterinthehydratesample.Gashydratesdissociatedintoiceandgasiftheiceinclusionswereinthehydratesample.Thesamplesofpropanehydrateswithinclusionsofunreactedsupercooledwateronly(withouticeinclusions)dissociatedintosupercooledwaterandgasbelowthepressureofthesupercooledwater-hydrate-gasmetastableequilibrium.
简介:在中密度C/C复合材料基体上采用催化化学气相沉积方法生长碳化硅纳米线(SiCnw)及制备碳化硅纳米线/碳化硅(SiCnw/SiC)涂层,研究中密度C/C复合材料基体上加载催化剂后涂层沉积及其抗氧化性能,结果表明:中密度基体上催化制备SiCnw涂层,可改善沉积效率,同时可抑制裂纹扩展,明显改善SiC涂层在1200℃的氧化防护能力。另外,在1500℃的空气中氧化10h后,SiCnw/SiC涂层氧化质量损失率仅为1.34%,明显低于质量损失率为8.67%的单层SiC涂层。
简介:Onenewsesquiterpenecompound,namely,illihenlactoneA(1),andonenewprenylatedC6–C3compound,illihenryioneH(2),alongwiththreeknownsesquiterpenes(3–5)wereisolatedfromthestemsofIlliciumhenryi.Thestructuresof1and2wereelucidatedbyspectroscopicevidenceincludingNMR,HRESIMSandcirculardichroism(CD).Compound2exhibitedaweakinhibitoryratioforbglucuronidasereleaseinducedbyplatelet-activatingfactor(PAF)inratpolymorphonuclearleukocytes(PMNs)invitro.