A vacuum adiabatic body and a refrigerator are provided. The vacuum adiabatic body may include a sheet base provided in a direction crossing a vacuum space between a first plate and a second plate, and at least one sheet protrusion that protrudes from the sheet base in at direction toward one of the first plate or the second plate to maintain an interval between the sheet base and the one of the first plate or the second plate.

A positive and negative pressure system and an operation method therefor, and a positive and negative pressure electrical appliance using the positive and negative pressure system. The positive and negative pressure electrical appliance comprises: a positive and negative pressure refrigerator, a positive and negative pressure washing machine, a vacuum dishwasher/fruit and vegetable cleaning machine, a super-oxygenated water washing range hood, a positive and negative pressure oven/fryer/microwave oven, a positive and negative pressure fresh-keeping compartment, a positive and negative pressure fresh-keeping warehouse, and a positive and negative pressure modular cabinet. Regulating airflow with positive and negative pressure, or carrying multiple effective loads such as ozone, an air catalyst, a negative ion, modified atmosphere gas and water for orderly getting in and out of or staying in a positive and negative pressure chamber, and exerting the required effects on objects therein.

A dilution refrigerator is provided. The dilution refrigerator includes a first thermal stage configured to be cooled to a first temperature, a second thermal stage configured to be cooled to a second temperature lower than the first temperature, and a vacuum chamber housing the first thermal stage and the second thermal stage. The dilution refrigerator also includes a first suspension system configured to suspend the first thermal stage from the vacuum chamber, and a second suspension system configured to suspend the second thermal stage from the vacuum chamber independently from the first thermal stage.

A dilution refrigerator is provided. The dilution refrigerator includes a plurality of thermal stages configured to be cooled to a plurality of temperatures. A coldest thermal stage of the plurality of thermal stages is disposed above warmer thermal stages of the plurality of thermal stages such that the coldest thermal stage is positioned furthest from a floor supporting the dilution refrigerator.