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| a. Direction of use | b. Object body | c. Technical field | ||||
| Positive use | Passive reduction | air | liquid | machinery | construction | … | |
| A. Positive pressure | □×◌ | * | ×◌ | □× | □× | ◌ |
|
| B. Negative pressure | ○□×◌ | ◊ | ○◊×◌ | □× | ○◊□× | ◌ |
|