简介:摘要目的了解婴幼儿智能发育状况和影响智能发育相关因素。方法对2246例婴幼儿行CDCC量表测试及相关因素调查,由2名专业人员进行测试和评分。结果智力发展指数(MDI)均值为91(±14),运动发展指数(PDI)均值为87(±14)。智力发展指数<70为7.0%,运动发展指数<70为10.9%;智力发展指数和运动发展指数>110发生率分别为6.2%和4.1%。多元回归分析可见与智力发育指数相关的因素有母亲职业、父亲文化、早产、高胆红素血症;与运动发育指数相关的因素有母亲职业和高胆红素血症。结论出生前、出生时、出生后的不良因素对婴幼儿的智能发育均有重要影响。
简介:MoleculardynamicssimulationsareperformedtoinvestigateCF3continuouslybom-bardingtheamorphoussiliconsurfacewithenergiesof10eV,50eV,100eVand150eVatnormalincidenceandroomtemperature.TheimprovedTersoff-Brennerpotentialswereused.Thesimu-lationresultsshowthatthesteady-stateetchingratesareabout0.019,0.085and0.1701for50eV,100eVand150eV,respectively.Withincreasingincidentenergy,atransitionfromC-richsurfacetoF-richsurfaceisobserved.IntheregionmodifiedbyCF3,SiFandCFspeciesaredominant.
简介:Fe2O3/activecarbon(Fe2O3/AC)nanocompositeswerereadilyfabricatedbypyrolyzingFe3+impregnatedactivecarboninanitrogenatmosphere.Theas-preparedcompositeswerestudiedbyX-raypowderdiffraction(XRD),X-rayphotoelectronspectroscopy(XPS)andtransmissionelectronmicroscopy(TEM).Thecapacitivepropertyofthecompositeswasinvestigatedbycyclicvoltammetry(CV)andgalvanostaticcharge-dischargetest.Physicalcharacterizationsshowthattheγ-Fe2O3finegrainsdispersedintheACwell,withameansizeof21.24nm.Electrochemicaltestsin6mol/LKOHsolutionsindicatethattheas-preparednanocompositesexhibitedimprovedcapacitiveproperties.Thespecificcapacitance(SC)ofFe2O3/ACnanocompositeswasupto188.4F/gthatwasderivedfrombothelectrochemicaldouble-layercapacitanceandpseudo-capacitance,whichwas78%largerthanthatofpristineAC.AsymmetriccapacitorwithFe2O3/ACnanocompositesaselectrodeshowedanexcellentcyclingstability.TheSCwasonlyreducedbyafactorof9.2%after2000cyclesatacurrentdensityof1A/g.