what is atm??????急用！！！20點

Standard atmosphere (symbol: atm) is a unit of pressure. Standard atmosphere is a non-SI unit that is internationally recognized. The 10th Conférence Générale des Poids et Mesures (10th CGPM) adopted standard atmosphere for general use and affirmed its definition of being precisely equal to 1,013,250 dynes per cm2 (101,325 Pa). This value is intended to represent the mean atmospheric pressure at mean sea level at the latitude of Paris, France, and as a practical matter, truly reflects the mean sea level pressure for many of the industrialized nations (those with latitudes similar to Paris).

[edit] Equivalencies
A pressure of 1 atm can also be stated as:

≡1.013 25 bar
≡101.325 kPa
≡1013.25 millibars (mbar, also mb) or hectopascals (hPa)
≡760 torr [B]
≈760.001 mm-Hg, 0°C, subject to revision as more precise measurements of mercury’s density become available [B, C]
≈29.9213 in-Hg, 0°C, subject to revision as more precise measurements of mercury’s density become available [C]
≈1.033 227 452 799 886 kg-force/cm²
≈1.033 227 452 799 886 technical atmosphere
≈1033.227 452 799 886 cm–H₂O, 4°C [A]
≈406.782 461 732 2385 in–H₂O, 4°C [A]
≈14.695 948 775 5134 pounds-force per square inch (psi)
≈2116.216 623 673 94 pounds-force per square foot (psf)
A This is the customarily-accepted value for cm–H₂O, 4°C. It is precisely the product of 1 kg-force per square centimeter (one technical atmosphere) times 1.013 25 (bar/atmosphere) divided by 0.980 665 (one gram-force). It is not accepted practice to define the value for water column based on a true physical realization of water (which would be 99.997 495% of this value because the true maximum density of Vienna Standard Mean Ocean Water is 0.999 974 95 kg/l at 3.984°C). Also, this “physical realization” would still ignore the 8.285 cm–H2O reduction that would actually occur in a true physical realization due to the vapor pressure over water at 3.984°C.
B Torr and mm-Hg, 0°C are often taken to be identical. For most practical purposes (to 5 significant digits), they are interchangeable.
C NIST value of 13.595 078(5) g/ml assumed for the density of Hg at 0°C

atmospheric pressure
automatic teller machine

ATM (asynchronous transfer mode) is a dedicated-connection switching technology that organizes digital data into 53-byte cell units and transmits them over a physical medium using digital signal technology. Individually, a cell is processed asynchronously relative to other related cells and is queued before being multiplexed over the transmission path.
Because ATM is designed to be easily implemented by hardware (rather than software), faster processing and switch speeds are possible. The prespecified bit rates are either 155.520 Mbps or 622.080 Mbps. Speeds on ATM networks can reach 10 Gbps. Along with Synchronous Optical Network (SONET) and several other technologies, ATM is a key component of broadband ISDN (BISDN).

ATM also stands for automated teller machine, a machine that bank customers use to make transactions without a human teller.

自動櫃員機（英語：automated teller machine 或 automatic teller machine）