计算机硬件 存储设备 释文 cleaning diskette 清洁软盘
- null boundary
- null cell
- null circle
- null class
- null cobordant
- null cobordant knot
- null code
- null column
- null complex
- null condition
- null cone
- null curve
- null divisor
- null element
- null ellipse
- null energy condition
- null event
- null expansion
- null field
- null-force system
- null form
- null formula
- null frame
- null function
- null geodesic