简介：<正>Rockwell公司新推出满足L和S波段功率需求的大功率晶体管及50ohm匹配功放模块。MESFETRF晶体管T4200将从基带至S频段提供25W的连续波输出功率。L1700功放模块提供35W的连续波功率。它专为950～1500MHz:频率范围设计,功率增益为10dB.通过与

简介：SinteringadditivestogelcastingSialon-SiCweredecidedbytheoptimizingexperiments.TheresultsshowthatSoalon-SiCcanbesinteredunder1450℃andsinteringtemperaturedecreasesby100℃,when2%～3%TiO2orGuangxiclayisusedassinteringadditive.

简介：以正硅酸乙酯和葡萄糖分别作Si源和C源，草酸和硼酸分别作催化剂，采用溶胶一凝胶法制备SiC前驱体，并采用碳热还原法制备纳米SiC。采用XRD、SEM对样品的物相和形貌进行表征。结果表明，用草酸作催化剂制备的前驱体在1550℃制备的SiC是颗粒与晶须的混合体，颗粒粒径为30~50nm，晶须长度为1～3μm，晶须直径为60～100nm；用硼酸作催化剂制备的前驱体其碳热还原温度显著降低，在1400℃就能制备出SiC颗粒与晶须的混合体，颗粒粒径为20~30nm，由于B加入后的抑制作用，SiC晶须的含量明显减少。

简介：Moleculardynamicssimulationswereperformedtostudytheinteractionbetweenatomichydrogenandsiliconcarbide.Inthepresentstudy,wefocusontheeffectofthesurfacetemperatureonHinteractingwithsiliconcarbide.ThesimulationresultsshowthattheretentionofHatomsinthesampledecreaseslinearlywithincreasingsurfacetemperature.ThedepthprofileanalysisshowsthatthesampleismodifiedbyHbombardment,andthedensityofHatomsisgreaterthanthoseofSiandCatomsneartheinterfaceregionbetweentheH-containingregionandthebulk.However,nearthesurfaceregionthedensitiesofH,SiandCatomsarealmostequivalent.Inthemodifiedlayer,thebondsconsistofSi-CandSi-HandC-H.ThefractionofSi-Cbondsisthegreatest.OnlyafewC-Hbondsarepresent.

简介：

简介：摘要：SiCf/SiC作为一种新型的陶瓷基复合材料，因其独有的高强度、高韧性、高热导率以及低热膨胀系数、低密度等特点，被广泛地应用于航空航天以及核能领域。材料由SiC纤维横纵交织编织而成，SiC本身就是超硬脆性材料，其莫氏硬度为9.5。而且SiCf/SiC材料在1500K的高温下仍能够保持材料的高强度性能，比镍基高温合金足足高了150K，但是其密度只有高温合金的30%，这一点在航空航天领域尤为重要。其优异的材料性能吸引了诸多学者对其展开应用研究，但是材料特有的属性给加工带来很大挑战。

简介：InaccordancewiththecharacteristicsofChina’smineralresources,Chineseresearchershavedevelopedthetitlenewconductorthatreachesinter-nationalstandards.TheRE-Alconductorhasbetterelectricalconductivity,highertensilestrength,bet-terductility,strongerresistancetowearingandcor-

简介：Recently,ShijiazhuangAluminiumPlantandChangchunResearchInstituteofAppliedChemistry,AcademiaSinica,co-developedanewmethodtopro-duceAl-SialloycastingpartsbyemployingAl-Sr-REalloyasmodificatorinsteadoftraditionalsodiumsalt.

简介：在传统的利用化爆和二级轻气炮作为驱动源的状态方程阻抗匹配实验中，为了考核不同标准材料的可信度，采用了标准材料交叉检验技术。即依次利用这些标准材料作为测量某个待测材料测量雨贡纽线的标准材料，通过比较待测材料雨贡纽线数据的一致性实现对这些标准材料的检验。2004年在神光-Ⅱ装置上完成的二倍频激光Al-Cu和Cu-A1阻抗匹配实验，是一种交叉实验。这两类实验不仅铝、铜二者互为标准材料和待测材料，而且实验包含了正反阻抗匹配两种类型：铝-铜正阻抗匹配实验中冲击波由低阻抗铝进入高阻抗待测材料铜，铜-铝反阻抗匹配实验中冲击波由高阻抗铜进入低阻抗待测材料铝中。

简介：IntroductionAsitiswell-known,Yamāri'sPramā(n)avārttikāla(n)kāra(t)īkāSupari(s)uddhā(hereafterPVATS)1onPraj(n)ākaragupta'sPramā(n)avārttikāla(n)kāra(hereafterPVA)containsalotofmaterialsconcerningvarioustopicswhichareveryimportantforhistoricalreconstructionofthelaterdevelopmentoftheBuddhistepistemologicalsystem,especiallythetraditionbeginningwithDharmakīrti'sPramā(n)avārttika(hereafterPV).

简介：Inthispaper,X-raydiffractogramanalysisandSEMobservationofAl4C3formedathightemperaturefromcarbon-containingrefractorieswithAlhavebeencarriedout.Aluminumaddedtocarbon-containingrefractoriesreactswithC(s)toformAl4C3(s)graduallyduringheatingfrom600℃to1200℃.ItisconsideredthattheinterlockedstructureofAl4C3platecrystalspromotestheoutstandingincreaseofhotmodulusofruptureofcarbon-containingrefractorieswithAl.TheHMORofcarbon-containingrefractoriesaddedwithAladditivefrom0to5wt％increasesby2.8timesbeingfrom6.5MPato18.2MPa.AfterathermochemicalcalculationforhydrationreactionprocessesofAl4C3andH2O(g),theequilibriumpartialpressurechartofH2O(g)inH2O-Al4C3-Al(OH)3systemvsvarioustemperatureshasbeenattained.TheH2O(g)partialpressureintheairneededfortheAl4C3hydrationreactionisnomorethan10～18atmatthetemperaturebelow120℃.Itisconsideredthattheburnedcarbon-containingrefractorieswithAlisextremelyeasytohydrateandthecrackingofburnedcarbon-containingrefractoriesisgeneratedbecausethatthehydrationexpansionis2.11timesduringtransformingfromAl4C3toAl(OH)3.ThefundamentalmeasureagainsthydrationoftherefractoriesistoinsulatetherefractoriesfromH2O(g)byvariousmeanssuchaspitchimpregnationorothersealingmaterials.

简介：铝和铬的性质有不少相似之处.它们都是两性金属,既能溶于酸又能溶于强碱;都被冷的浓硝酸钝化,其氧化物Al2O3、Cr2O3都是熔点高、硬度大的物质,其氢氧化物Al（OH）3、Cr（OH）3都是难溶于水的两性氢氧化物,既能溶于酸又能溶于强碱.本文利用Al—H2O系统的（?）—pH图及Cr—H2O系统的（?）—pH图,对铝和铬及其氢氧化物的两性进行分析.一、Al—H2O系统（?）—pH图图1为Al—H2O系统的（?）—pH图,其作法是:（?）线代表H+/H2线.根据（?）（H+/H2）=-0.0592pH-（0.0592/2）1g（P（H2））

简介：摘要：详细介绍了新一代机车SiC牵引变流器的工作原理，系统参数和仿真及试验验证。重点分析SiC牵引变流器的主电路及技术参数，通过SiC牵引变流器的相关仿真及试验，验证SiC牵引变流器的各项性能指标，与既有HX机车相比具有显著代际特征，满足轨道交通产品更新迭代要求。

简介：Photoluminescenceevaluationofpandntype6H-SiCsampleshasbeendone.Resultsshowthatatlowtemperaturethephotoluminescenceof6H-SiCisclearlydominatedbydonor-acceptorpairtransitions,insomecase,free-to-donortransitioncouldbeobservedathighertemperature.Thethermalquenchingprocessesofthephotoluminescencehavebeeninvestigatedtodeterminethepossibleionizationnenergiesoftheimpurities.

简介：针对C／SiC轻质复合材料结构，将三维编织C／SiC复合材料看作是组分材料的空间结构物，由有序的细观结构单胞叠合而成。采用细观结构单胞作为离散单元对三维编织复合材料结构进行宏观网格剖分，利用有限元方法研究复合材料悬臂板动态特性，计算结果与理论值符合较好。

简介：Theholeinjection,theradiativerecombinationandthedevicelumi-nescentefficienciesofamorphoussiliconcarbidethinfilmp-I-njunctionlightemit-tingdiodesarequantitativelycalculated,andtheeffectofthecarrier(especiallythehole)injectionandrecombinationprocessesonthedeviceluminescentcharacteris-ticsarerevealed.Withoutconsideringthedevicejunctiontemperature,itisroundthatthedeviceluminescentefficiencymainlydependsontheholeinjectionefficiencyatlowfieldandtheholeradiativerecombinationefficiencyathighfieldrespective-ly.Thetheoreticalanalysesareinwellagreementwiththeexperimentalresults.

简介：为了研究高开关速度下寄生参数对SiCMOSFET开关特性的影响,以双脉冲测试电路为平台,借助于LTspice软件,探讨了栅极寄生电阻RG、寄生电感以及寄生电容对SiCMOSFET开通和关断时间,开通和关断损耗,电压和电流尖峰的影响。结果表明：RG对寄生振铃有抑制作用,但需要以增大开关时间和开关损耗为代价;源极电感LS具有负反馈作用,其对寄生振铃的抑制也是以增大开关时间和开关损耗为代价;漏极电感LD和栅极电感LG的增加都会使电流和电压尖峰增大,LD的作用较LG明显;漏源极电容CDS是产生电压和电流尖峰的主要因素;栅漏极电容CGD的大小决定了漏源极电压uDS的变化速率;栅源极电容CGS主要决定了器件的开关延时时间和漏极电流的变化速率,对寄生振铃影响不大。

简介：Theapplicabilityandlimitationofseveralquadraticstrengththeorieswereinvestigatedwithrespectto2D-C/SiCand2.5D-C/SiCcomposites.Akindofdamage-basedfailurecriterion,referredtoasD-criterion,isproposedfornonlinearceramiccomposites.Meanwhile,thenewlydevelopedcriterionispreliminarilyvalidatedundertension-shearcombinedloadings.ThepredictionshowsthatthefailureenvelopegivenbyD-criterionislowerthanthatfromTsai–HillandHoffmancriteria.Thisrevealsthatthedamage-basedcriterionisreasonableforevaluationofdamage-dominatedfailurestrength.

简介：HightemperatureoxidationbehavioroftwokindsofnitridebondedSiCbasedrefractorieswasinvestigatedat11001500℃bymeansofX-raydiffractometer,scanningelectronicmicroscopyandthermogravimetry.Theresultsshowthat:(1)withthetemperatureincreasing,theoxidationmassincrementrateofthespecimenincreasesfirstandthendecreases,andoxidationpassivationoccurs;(2)theoxidationresistanceofSiAlONbondedSiCrefractoriesissuperiortothatofSi3N4bondedSiCrefractories;(3)hightemperatureoxidationresultsintheincreaseofcompressivestrengthatroomtemperatureofSiCbasedrefractoriescomparedwithspecimenbeforeoxidation;thecompressivestrengthofSiAlONbondedSiCspecimensoxidizedathightemperaturesdecreaseswiththeincreaseofthetemperatureasaresultofformationandburstofsurfacebubble,whilethedecreaseofcompressivestrengthofSi3N4bondedSiCspecimensoxidizedathightemperaturesisowingtotheincreaseoftheconsistencyofnet-likecrackassociatedwithcristobalitetransformationduringcooling.

简介：Lowcement(LC)andultra-lowcement(ULC)bauxite-SiCcastablesareimportantandhighperformancemonolithicrefiactoriesandtheyhavebeenwidelyusediniron-makingandincineratorlinings.Inthiswork,rheo-logicalbehaviorofLCandULCbauxite-basedSiC-contain-ingcastableshasbeenstudied,includingtheeffectsofSiCcontentandcementcontentonrheologicalpropertiesofthecastables.TheresultsshowthatwithanincreaseofSiCandcementcontent,rheologicalpropertiesofthecastablesdeteriorate.Ontheotherhand,moderateamountsofSiC(4%～8%)andofcalciumaluminatecement(2%～4%)haveveryslightinfluenceonrheologicalproperties,(i.e.whenthecastablesareshearedtheirtorqueandyieldtorqueonlyslightlyincreasewiththeshearingspeed).Therheologicalcharacteristicsofthecastablesfol-lowBinghamfiuidandalwaysshowshearthinningbehav-ior.