Besel
... Bend 挠度,弯曲 Besel 监视孔 BLAS 偏置,偏压 ...
observation port
... observation mirror 观测镜 observation port 观察孔,监视孔 observe 观察,检查 ...
sightglass
... 监视孔,窥视孔 judas window 监视孔 besel; judas window; sightglass 孔眼,视孔 oylet ...
besel
sightglass brick