简介:利用角分辨紫外光电子谱对乙烯和乙炔气体在Ru(1010)表面的吸附及与K的共吸附的研究结果表明:当衬底温度超过200K,乙烯即发生脱氢反应,σCH和σCC能级均向高结合能方向移动。在室温下,σCH和σCC能级位置与乙炔在Ru(1010)表面的吸附时的分子能级完全一致。乙烯发生脱氢反应后的主要产物为乙炔。衬底温度从120K到室温,Ru(1010)表面上乙炔的σCH和σCC能级均未发现变化。室温下乙炔仍然可以在Ru(1010)表面以分子状态稳定吸附。在有K的Ru(1010)表面上,室温时σCC谱峰几乎。碱金属K的存在促进了乙炔的分解。
简介:Anewapproachtodeterminealltheelectro-elasticconstantsofthepiezoelectriccrystalsinclass4mmhasbeenputforward.Asanexample,alltheconstantsofLithiumTetraborate(Li2B4O7)crystalhavebeenmeasuredbymeansoftheapproach.Theoutstandingadvantageoftheapproachisthatiton-lyneedstoemployinmeasurementthreecrystalplatesdifferentlyoriented.
简介:Objective:Tostudythevaccinepotencyofgene-modifiedtumorcells.Methods:TheEL-4lymphomawastransducedwithrecombinantretroviruscontainingthemurineGM-CSFgeneorB7-1gene.Theeffectofgenetransductiononantitumorimmunitywasinvestigated.Results:Flowcytometryanalysisshowedthatexpressionoftheirsurfacemarkerbetweenwild-typeEL-4cellsandgenetransducedtumorcellswasthesameexceptforCD80positiveinB7-1genetransducedcells.GM-CSFgeneorB7-1genetransducedEL-4cellsresultedinremarkablelossoftumorigenicityinsyngeneticmice.ThesystemicprotectiveimmunitywasinducedagainstthechallengewithEL-4/wtcells.TherapeuticvaccinewithEL-4/GM-CSForEL/7-1cellscouldretardthegrowthofestablishedearly-stageEL-4/wttumorsignificantly,butnotretardthegrowthoflate-stageEL-4/wttumor.IrradiatedGM-CSFgenetransducedEL-4cellsshowedstrongvaccineeffectagainstEL-4cellchallenge,butirradiatedB7-1genetransducedEL-4cellsshowedweakvaccineeffect.RemarkablecooperativeantitumoreffectagainstEL-4cellchallengewasobservedwhenbothirradiatedEL-4/GM-CSFandEL-4/B7-1wereinoculatedtogether.Conclusion:GM-CSFgeneorB7-1genetransducedcombinationofthetwokindsofvaccinemayhavepotentialapplicationvalueinhumancancertreatment.