简介:当散射体系中除散射体外还存在微电子密度起伏时,实测散射强度将形成对Porod定理的正偏离,从而使散射体的散射失真。提出了一种在长狭缝准直条件下应用模糊强度校正正偏离的方法:作出ln[q^3I^-(q)]-q^2曲线,用公式n[q^3I(q)]=InK'+σ^2q^2拟合大波矢区直线,求出斜率σ^2,作出ln[q^3I^-(q)]-σ^2q^2-q^2曲线即为无偏离的Porod曲线,由此曲线再还原出无偏离的散射强度,即I^-'(q)=exp{ln[q^3I^-(q)]-σ^2q^2}/q^3,再以醇热法合成的介孔氧化锆粉体为例进行了讨论。
简介:控制棒驱动机构(CRDM)下部Ω焊缝及母材显示在焊前、焊后、水压试验后的液体渗透检测(PT)中均有出现,其形态基本为小于1mm的非线性显示,主要分布在焊缝两侧的弧段区。对显示的检测表明,原材料性能满足技术规格书的要求,同时存在C类、D类超尺寸夹杂物。PT显示部位可观察到非金属夹杂物及微裂纹。结合完工报告复核、材料复验、国外供货对比等分析认为显示与超尺寸非金属夹杂物相关。显示可采取有限打磨进行处理。建议提高原材料夹杂物采购技术要求,控制原材料中Al、Si、O的含量,在失效时可考虑覆盖堆焊(OVERLAY)、夹紧装置(CSCA)的维修方式以及进行适当的在役跟踪检查。
简介:Anumericalsimulationmodelfor252kVpuffercircuitbreakerisconstructed,byusingaprovencommercialcomputationalfluiddynamics(CFD)package,PHOENICS.Themodeltakesintoaccountthemovingpartsinthecircuitbreaker,turbulenceenhancedmomentumandenergytransport,radiationtransport.ThearcingprocessinaSF6puffercircuitbreakerwithtwohollowcontactsissimulatedunderdifferentconditions,andthesimulationresultsareverifiedwithexperimentalresults.Throughsimulation,thepressure,temperatureandvelocityinthearcquenchingchambercanbeobtained.Thesimulationmodelisalsocapableofpredictingtheinfluenceofdesignparametersvariationsonbreakerperformance,andcanthushelptoreducethenumberofshort-circuittestsduringthedesignstage.
简介:Anewrectangularpulsetriggergeneratorhasbeendevelopedwhichcangeneratetwo10kVpulseswitharisetimelessthan1ns,ajitterof0.2nsandawidthofabout10nsand40ns,respectively.Thisgeneratorusestwopolymer-foilswitchesand25ohmBlumleintransmissionlinescomposedoftwo-parallelstandardcoaxialcablesdischargingintotwo50ohmoutputcables.Thepulsewidthandthedelaybetweentwopulsescanbeadjustedbychangingthelengthofthecables.