GSC (gas–solid chromatography) See
gas chromatography.
G-series See nerve agents.
guanidine A crystalline basic compound HN:C(NH 2 ) 2 , related to urea.
guanine A *purine derivative. It is
one of the major component bases of
*nucleotides and the nucleic acids
*DNA and *RNA.
gum Any of a variety of substances
obtained from plants. Typically they
are insoluble in organic solvents but
form gelatinous or sticky solutions
with water. Gum resins are mixtures
of gums and natural resins. Gums are
produced by the young xylem vessels
of some plants (mainly trees) in response to wounding or pruning. The
exudate hardens when it reaches the
plant surface and thus provides a
temporary protective seal while the
cells below divide to form a permanent repair. Excessive gum formation
is a symptom of some plant diseases.
guncotton See cellulose nitrate.
gun metal A type of bronze usually
containing 88–90% copper, 8–10% tin,
and 2–4% zinc. Formerly used for cannons, it is still used for bearings and
other parts that require high resistance to wear and corrosion.
gunpowder An explosive consisting of a mixture of potassium nitrate,
sulphur, and charcoal.
gypsum A monoclinic mineral
form of hydrated *calcium sulphate,
CaSO 4 .2H 2 O. It occurs in Üve varieties: rock gypsum, which is often
red stained and granular; gypsite, an
impure earthy form occurring as a
surface deposit; alabaster, a pure
Üne-grained translucent form; satin
spar, which is Übrous and silky; and
selenite, which occurs as transparent
crystals in muds and clays. It is used
in the building industry and in the
manufacture of cement, rubber,
paper, and plaster of Paris.
gyromagnetic ratio Symbol γ.
The ratio of the angular momentum
of an atomic system to its magnetic
moment. The inverse of the gyromagnetic ratio is called the magnetomechanical ratio.
257
gyromagnetic ratio
g
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gas chromatography.
G-series See nerve agents.
guanidine A crystalline basic compound HN:C(NH 2 ) 2 , related to urea.
guanine A *purine derivative. It is
one of the major component bases of
*nucleotides and the nucleic acids
*DNA and *RNA.
gum Any of a variety of substances
obtained from plants. Typically they
are insoluble in organic solvents but
form gelatinous or sticky solutions
with water. Gum resins are mixtures
of gums and natural resins. Gums are
produced by the young xylem vessels
of some plants (mainly trees) in response to wounding or pruning. The
exudate hardens when it reaches the
plant surface and thus provides a
temporary protective seal while the
cells below divide to form a permanent repair. Excessive gum formation
is a symptom of some plant diseases.
guncotton See cellulose nitrate.
gun metal A type of bronze usually
containing 88–90% copper, 8–10% tin,
and 2–4% zinc. Formerly used for cannons, it is still used for bearings and
other parts that require high resistance to wear and corrosion.
gunpowder An explosive consisting of a mixture of potassium nitrate,
sulphur, and charcoal.
gypsum A monoclinic mineral
form of hydrated *calcium sulphate,
CaSO 4 .2H 2 O. It occurs in Üve varieties: rock gypsum, which is often
red stained and granular; gypsite, an
impure earthy form occurring as a
surface deposit; alabaster, a pure
Üne-grained translucent form; satin
spar, which is Übrous and silky; and
selenite, which occurs as transparent
crystals in muds and clays. It is used
in the building industry and in the
manufacture of cement, rubber,
paper, and plaster of Paris.
gyromagnetic ratio Symbol γ.
The ratio of the angular momentum
of an atomic system to its magnetic
moment. The inverse of the gyromagnetic ratio is called the magnetomechanical ratio.
257
gyromagnetic ratio
g
www.AzShimi.ir www.AzShimi.com