Aberration of electronic lens made by electron gun and aberration of magnetic deflection system made by dy are comprehensively investigated , so is the shadow mask ' s effect on electron beam landing screen error . the conclusion can be get that , because the distribution of electron beam landing screen ( distribution of luminance ) is affected by many kinds of factors , it cannot get the correct function by calculation , and should be get by measurement instead 全面分析了cpt电子枪发射系统形成的电子透镜像差与磁偏转系统形成的偏转像差；分析了荫罩的自身厚度与位移对电子束着屏的影响，并由此得出结论，着屏电子束分布(即亮度分布)受着许多因素的影响，理论分析是半定量的，着屏电子束分布需要用精确的测量仪器来测量。
Effects of 4 - wk simulated microgravity on the mrna expression of agt and ace in arterial tissues of different body regions of rats 4 - wk simulated microgravity induced a significant increase of agt mrna expression in basilar arterial tissues ( p < 0 . 05 , n = 5 ) , and a decreasing tendency in femoral arterial tissues ( p > 0 . 05 , n = 5 ) 4周模拟失重对不同部位动脉组织agt和acemrna表达的影咱半定量的rt pcr分析结果表明，与同步对照大鼠相比， 4周模拟失重大鼠基底动脉t的mrna表达显著增加（ p 0刀5 ， n二5 ） ，而股动脉tmrnmrna表达则呈减少趋势（ p 0刀5 ， 。
