GE CT除定期更换球管外,机架稳定性极高,但扫描床较容易出故障。除Revolution系列外GE CT均配置GT1700V扫描床。本文分析总结了GT1700V扫描床的常见故障2例,以供同行交流。1故障一故障现象:扫描床运动时产生摩擦声。故障分析与排除:GE...GE CT除定期更换球管外,机架稳定性极高,但扫描床较容易出故障。除Revolution系列外GE CT均配置GT1700V扫描床。本文分析总结了GT1700V扫描床的常见故障2例,以供同行交流。1故障一故障现象:扫描床运动时产生摩擦声。故障分析与排除:GE扫描床经常会出现人为造成的外壳变形。经常被撞到的外壳部分是几片金属挡板,其材质容易变形,从而导致扫描床升降时产生摩擦声。对于轻微变形,一般将挡板扳直即可。此外,对扫描床要加强保护,比如建立护栏,更好的做法是放置台阶凳,以减少扫描床升降频率,保护信号线。如机器经常做增强,造影剂会滴落到床上,形成结晶,一级床运动时也会产生明显的摩擦声。对于此类故障,需要将一级床推到最外侧,拆下两侧板,清洗床面。展开更多
The fabrication and characterization of 1700 V 7 A 4H-SiC vertical double-implanted metal-oxide-semiconductor field-effect transistors （VDMOSFETs） are reported. The drift layer is 17μm in thickness with 5 × 10...The fabrication and characterization of 1700 V 7 A 4H-SiC vertical double-implanted metal-oxide-semiconductor field-effect transistors （VDMOSFETs） are reported. The drift layer is 17μm in thickness with 5 × 10^15 cm^-3 n-type doping, and the channel length is 1μm. The MOSFETs show a peak mobility of 17cm2/V.s and a typical threshold voltage of 3 V. The active area of 0.028cm2 delivers a forward drain current of 7A at Vcs = 22 V and VDS= 15 V. The specific on-resistance （Ron,sv） is 18mΩ.cm2 at VGS= 22 V and the blocking voltage is 1975 V （IDS 〈 lOOnA） at VGS = 0 V.展开更多
基金Supported by the National Science and Technology Major Project of the Ministry of Science and Technology of China under Grant No 2013ZX02305
文摘The fabrication and characterization of 1700 V 7 A 4H-SiC vertical double-implanted metal-oxide-semiconductor field-effect transistors （VDMOSFETs） are reported. The drift layer is 17μm in thickness with 5 × 10^15 cm^-3 n-type doping, and the channel length is 1μm. The MOSFETs show a peak mobility of 17cm2/V.s and a typical threshold voltage of 3 V. The active area of 0.028cm2 delivers a forward drain current of 7A at Vcs = 22 V and VDS= 15 V. The specific on-resistance （Ron,sv） is 18mΩ.cm2 at VGS= 22 V and the blocking voltage is 1975 V （IDS 〈 lOOnA） at VGS = 0 V.
