Omega Engineering CYTX231 Series, Руководство пользователя, Страница: 35 / 38

Omega Model CYTX231 User’s Manual
Glossary of Terminology B-3
liquid helium (LHe) . Used for low temperature and superconductivity research:
minimum purity 99.998%. Boiling point at 1 atm = 4.2 K. Latent heat of vaporization
= 2.6 kilojoules per liter. Liquid density = 0.125 kilograms per liter.
EPA Hazard Categories: Immediate (Acute) Health and Sudden Release of
Pressure Hazards
DOT Label: Nonflammable Gas DOT Name: Helium, Refrigerated Liquid
DOT Class: Nonflammable Gas DOT ID No: UN 1963
liquid nitrogen (LN
2
) . Also used for low temperature and superconductivity research
and for its refrigeration properties such as in freezing tissue cultures: minimum
purity 99.998%, O
2
8 ppm max. Boiling point at 1 atm = 77.4 K. Latent heat of
vaporization = 160 kilojoules per liter. Liquid density = 0.81 kilograms per liter.
EPA Hazard Categories: Immediate (Acute) Health and Sudden Release of
Pressure Hazards
DOT Label: Nonflammable Gas DOT Name: Nitrogen, Refrigerated Liquid
DOT Class: Nonflammable Gas DOT ID No: UN 1977
material safety data sheet (MSDS) . OSHA Form 20 contains descriptive information
on hazardous chemicals under OSHA’s Hazard Communication Standard (HCS).
These data sheets also provide precautionary information on the safe handling of
the gas as well as emergency and first aid procedures.
MKSA System of Units . A system in which the basic units are the meter, kilogram,
and second, and the ampere is a derived unit defined by assigning the magnitude
4
π
x 10
-7
to the rationalized magnetic constant (sometimes called the permeability
of space).
NBS . National Bureau of Standards. Now referred to as NIST.
National Institute of Standards and Technology (NIST) . Government agency
located in Gaithersburg, Maryland and Boulder, Colorado, that defines
measurement standards in the United States.
platinum (Pt) . A common temperature sensing material fabricated from pure platinum
to make the Omega PT family of resistance temperature sensor elements.
prefixes . SI prefixes used throughout this manual are as follows:
Factor Prefix Symbol
10
24
yotta Y
10
21
zetta Z
10
18
exa E
10
15
peta P
10
12
tera T
10
9
giga G
10
6
mega M
10
3
kilo k
10
2
hecto h
10
1
deka da
Factor Prefix Symbol
10
-1
deci d
10
-2
centi c
10
-3
milli m
10
-6
micro µ
10
-9
nano n
10
-12
pico p
10
-15
femto f
10
-18
atto a
10
-21
zepto z
10
-24
yocto y
probe . A long, thin body containing a sensing element which can be inserted into a
system in order to make measurements. Typically, the measurement is localized to
the region near the tip of the probe.
repeatability . The closeness of agreement among repeated measurements of the
same variable under the same conditions.
2
self-heating . Heating of a device due to dissipation of power resulting from the
excitation applied to the device. The output signal from a sensor increases with
excitation level, but so does the self-heating and the associated temperature
measurement error.