简介:HighlyactiveandselectiveCu/SiO2catalystsforhydrogenationofdimethyloxalate(DMO)toethyleneglycol(EG)weresuccessfullypreparedbymeansofaconvenientone-potsyntheticmethodwithtetraethoxysilane(TEOS)asthesourceofsilica.XRD,H2-TPR,SEM,TEM,XRFandN2physisorptionmeasurementswereperformedtocharacterizethetextureandstructureofCu/SiO2catalystswithdifferentcopperloadings.TheactivecomponentswerehighlydispersedonSiO2supports.Furthermore,thecoexistenceofCu0andCu+contributedalottotheexcellentperformanceofCu-TEOScatalysts.TheDMOconversionreached100%andtheEGselectivityreached95%at498Kand2MPawithahighliquidhourlyspacevelocityoverthe27-Cu-TEOScatalystwithanactualcopperloadingof19.0%(massfraction).
简介:WehavedevelopedaplasmaetchingsimulatortoinvestigatetheevolutionofpatternprofilesinSiO2materialunderdifferentplasmaconditions.Thismodelfocusesonenergyandangulardependentetchingyield(physicalsputteringinthispaper),neutralandionangulardistributions,andreflectionofionsorneutralsonthesurfaceofaphotoresistorSiO2.TheeffectofpositivechargeaccumulationonthesurfaceofinsulatedmaskorSiO2isstudiedandthechargeaccumulationcontributestoadeflectionofiontrajectory.Thewaferprofileevolutionhasbeensimulatedusingacellular-automata-likemethodunderradio-frequency(RF)biasanddirect-current(DC)bias,respectively.Onthebasisofthecriticalroleofangulardistributionofionsorneutrals,thewaferprofileevolutionhasbeensimulatedfordifferentvariancesofangles.Observedmicrotrenchinghasbeenwellreproducedinthesimulator.Theratioofneutralstoionshasbeenconsideredandtheresultshowsthatbecausetheneutralsarenotacceleratedbyanelectricfield,theirenergyismuchlowercomparedwithions,sotheyareeasilyreflectedonthesurfaceofSiO2,whichmakesthetrenchshallower.
简介:采用浸渍法制备了不同La掺杂量的Ni—SiO2催化剂,研究了La掺杂量对Ni—SiO2催化剂的Ni活性金属粒径、还原性能、甲烷催化裂解寿命以及反应后生成碳纤维的影响。结果表明:La、Ni物质的量比由0增长至0.3时,Ni-SiO2催化剂的寿命显著提高,而当La、Ni物质的量比由0.3增长至0.6时,催化剂寿命在一定程度上略有降低;La、Ni物质的量比由0增长至0.6时,还原后催化剂Ni金属的平均粒径从26.43nm不断降低至10.57nm。不同La掺杂量Ni—SiO2催化剂甲烷催化裂解过程中Ni金属平均粒径变化趋势明显不同,n(La):n(Ni)=0的Ni—SiO2催化剂随反应进行Ni金属平均粒径不断降低,而n(La):n(Ni)=0.3的Ni—SiO2催化剂随反应进行Ni金属平均粒径则不断升高。碳纤维形态受掺La掺杂量影响较大,随La、Ni物质的量比由0增长至0.3,反应过程中生成的碳纤维管径变粗,而随La、Ni物质的量比由0.3增长至0.6,碳纤维变短。
简介:目的研究磁性聚乳酸-羟基乙酸氧化苦参碱纳米粒(M-PLGA-OM-NP)的制备工艺,并对纳米粒子进行评价。方法运用复乳法制备M-PLGA-OM-NP,通过透射电子显微镜观察纳米粒形态,并对纳米粒的平均粒径、载药量、包封率、体外释药情况等进行评价。结果纳米粒外观呈规则球形,其平均粒径为146.5nm,载药量为7.61%,包封率为44.8%。突释后至第72小时,纳米粒维持较稳定的释药速度,累积释放达52.9%。72~240h,药物释放缓慢,累计释放约为16.6%,体外释放符合Ritgerpeppas方程lny=1.2806+lnt。氧化苦参碱药性不受温度影响。结论获得了较满意的M-PLGA-OM-NP制备工艺,其过程简单,粒子性状符合要求。
简介:目的采用星点设计-效应面法优化淫羊藿苷固体脂质纳米粒制备工艺。方法采用高压乳匀法制备淫羊藿苷固体脂质纳米粒,考察卵磷脂,F68,投药量对包封率,载药量以及药物利用率的影响,应用星点设计-效应面法优化处方工艺。结果采用二项式方程拟合实验结果,相关性较好(r〉0.9),采用优化后处方条件对预测值进行验证,包封率为(93.09±0.13)%,载药量为(6.34±0.18)%,药物利用率为(84.53±2.45)%,与预测值偏差较小。结论采用星点设计-效应面法优化淫羊藿苷固体脂质纳米粒处方工艺,快速简单,预测准确度高,是较为理想的处方设计及优化方法。