| slovo | definícia |
roentgen
(mass) | roentgen
- rentgen |
roentgen
(encz) | roentgen,rentgen n: Zdeněk Brož |
Roentgen
(gcide) | Rontgen \R["o]nt"gen\, Roentgen \Roent"gen\, a.
Of or pertaining to the German physicist Wilhelm Konrad
R["o]ntgen, or the rays discovered by him; as, R["o]ntgen
apparatus.
[Webster 1913 Suppl.] |
roentgen
(wn) | roentgen
n 1: a unit of radiation exposure; the dose of ionizing
radiation that will produce 1 electrostatic unit of
electricity in 1 cc of dry air [syn: roentgen, R]
2: German physicist who discovered x-rays and developed
roentgenography (1845-1923) [syn: Roentgen, {Wilhelm Konrad
Roentgen}, Rontgen, Wilhelm Konrad Rontgen] |
| | podobné slovo | definícia |
roentgen
(mass) | roentgen
- rentgen |
roentgen
(encz) | roentgen,rentgen n: Zdeněk Brož |
roentgen ray
(encz) | roentgen ray, n: |
roentgenogram
(encz) | roentgenogram, n: |
roentgenographic
(encz) | roentgenographic, adj: |
roentgenography
(encz) | roentgenography, n: |
roentgenoscope
(encz) | roentgenoscope, n: |
roentgenovo záření
(czen) | Roentgenovo záření,x-radiationn: [obec.] mamm |
Roentgen ray
(gcide) | Ray \Ray\, n. [OF. rai, F. rais, fr. L. radius a beam or ray,
staff, rod, spoke of a wheel. Cf. Radius.]
1. One of a number of lines or parts diverging from a common
point or center, like the radii of a circle; as, a star of
six rays.
[1913 Webster]
2. (Bot.) A radiating part of a flower or plant; the marginal
florets of a compound flower, as an aster or a sunflower;
one of the pedicels of an umbel or other circular flower
cluster; radius. See Radius.
[1913 Webster]
3. (Zool.)
(a) One of the radiating spines, or cartilages, supporting
the fins of fishes.
(b) One of the spheromeres of a radiate, especially one of
the arms of a starfish or an ophiuran.
[1913 Webster]
4. (Physics)
(a) A line of light or heat proceeding from a radiant or
reflecting point; a single element of light or heat
propagated continuously; as, a solar ray; a polarized
ray.
(b) One of the component elements of the total radiation
from a body; any definite or limited portion of the
spectrum; as, the red ray; the violet ray. See Illust.
under Light.
[1913 Webster]
5. Sight; perception; vision; -- from an old theory of
vision, that sight was something which proceeded from the
eye to the object seen.
[1913 Webster]
All eyes direct their rays
On him, and crowds turn coxcombs as they gaze.
--Pope.
[1913 Webster]
6. (Geom.) One of a system of diverging lines passing through
a point, and regarded as extending indefinitely in both
directions. See Half-ray.
[1913 Webster]
Bundle of rays. (Geom.) See Pencil of rays, below.
Extraordinary ray (Opt.), that one of two parts of a ray
divided by double refraction which does not follow the
ordinary law of refraction.
Ordinary ray (Opt.) that one of the two parts of a ray
divided by double refraction which follows the usual or
ordinary law of refraction.
Pencil of rays (Geom.), a definite system of rays.
Ray flower, or Ray floret (Bot.), one of the marginal
flowers of the capitulum in such composite plants as the
aster, goldenrod, daisy, and sunflower. They have an
elongated, strap-shaped corolla, while the corollas of the
disk flowers are tubular and five-lobed.
Ray point (Geom.), the common point of a pencil of rays.
Roentgen ray, R["o]ntgen ray (r[~e]nt"g[e^]n r[=a]`)
(Phys.), a form of electromagnetic radiation generated in
a very highly exhausted vacuum tube by an electrical
discharge; now more commonly called X-ray. It is
composed of electromagnetic radiation of wavelength
shorter than that of ultraviolet light but longer than
that of gamma rays. It is capable of passing through many
bodies opaque to light, and producing photographic and
fluorescent effects by which means pictures showing the
internal structure of opaque objects are made, called
X-rays, radiographs, sciagraphs, X-ray photographs,
radiograms. So called from the discoverer, W. C.
R["o]ntgen.
X ray, the R["o]ntgen ray; -- so called by its discoverer
because of its enigmatical character, x being an algebraic
symbol for an unknown quantity.
[1913 Webster +PJC]Roentgen ray \Roentgen ray\
the Anglicised spelling of R["o]ntgen ray. Same as X ray.
[PJC]Rontgen ray \R["o]ntgen ray\, Roentgen ray \Roentgen ray\ [see
R["o]ntgen.] (Physics)
An X-ray; originally, the term was applied to any of the
rays produced when cathode rays strike upon surface of a
solid (as the wall of the vacuum tube), but now it refers
specifically to electromagnetic radiation having wavelengths
from 10^-3 nm to 10 nm, immediately below ultraviolet
radiation on the wavelength scale. R["o]ntgen rays are noted
for their penetration of opaque substances, as wood and
flesh, their action on photographic plates, and their
fluorescent effects. They were called X rays by their
discoverer, W. K. R["o]ntgen. They are one of the forms of
ionizing radiation, which can have damaging effects on living
cells. They also ionize gases, but cannot be reflected, or
polarized, or deflected by a magnetic field. They are used in
examining opaque objects, especially in medicine for
visualizing organs and other objects inside the human body,
as for locating fractures or bullets, and examining internal
organs for abnormalities.
[Webster 1913 Suppl. +PJC] |
Roentgen rays
(gcide) | X ray \X ray\, X-ray \X-ray\([e^]ks"r[=a]`), n. [so called by
its discoverer because of its enigmatical character, x being
an algebraic symbol for an unknown quantity.] (Physics)
Originally, any of the rays produced when cathode rays strike
upon surface of a solid (as a copper target or the wall of
the vacuum tube); now defined as electromagnetic radiation
with a wavelength of 0.1 to 10 nanometers. X-rays are noted
for their penetration of many opaque substances, as wood and
flesh, their action on photographic plates, and their
fluorescent effects. They were called X rays by their
discoverer, W. K. R["o]ntgen, but were also referred to for
some time as Roentgen rays. The term X-ray has become the
most common designation. They also ionize gases, but cannot
be reflected, or polarized, or deflected by a magnetic field.
They are used in examining objects opaque to visible light,
as for imaging bones or other structures inside the human
body, and for detecting flaws in metal objects, such as in
welds.
[Webster 1913 Suppl. +PJC] X ray |
roentgen
(wn) | roentgen
n 1: a unit of radiation exposure; the dose of ionizing
radiation that will produce 1 electrostatic unit of
electricity in 1 cc of dry air [syn: roentgen, R]
2: German physicist who discovered x-rays and developed
roentgenography (1845-1923) [syn: Roentgen, {Wilhelm Konrad
Roentgen}, Rontgen, Wilhelm Konrad Rontgen] |
roentgen ray
(wn) | roentgen ray
n 1: electromagnetic radiation of short wavelength produced when
high-speed electrons strike a solid target [syn: X ray,
X-ray, X-radiation, roentgen ray] |
roentgenium
(wn) | roentgenium
n 1: a radioactive transuranic element [syn: roentgenium,
Rg, element 111, atomic number 111] |
roentgenogram
(wn) | roentgenogram
n 1: a radiogram made by exposing photographic film to X rays;
used in medical diagnosis [syn: roentgenogram, X ray,
X-ray, X-ray picture, X-ray photograph] |
roentgenographic
(wn) | roentgenographic
adj 1: relating to or produced by roentgenography |
roentgenography
(wn) | roentgenography
n 1: radiography that uses X-rays to produce a roentgenogram
[syn: roentgenography, X-ray photography] |
roentgenoscope
(wn) | roentgenoscope
n 1: an X-ray machine that combines an X-ray source and a
fluorescent screen to enable direct observation [syn:
fluoroscope, roentgenoscope] |
wilhelm konrad roentgen
(wn) | Wilhelm Konrad Roentgen
n 1: German physicist who discovered x-rays and developed
roentgenography (1845-1923) [syn: Roentgen, {Wilhelm
Konrad Roentgen}, Rontgen, Wilhelm Konrad Rontgen] |
roentgenium
(elements) | roentgenium
Symbol: Rg
Atomic number: 111
Atmic weight: 280
Roentgenium is placed as the heaviest member of the group 11 (IB)
elements,
although a sufficiently stable isotope is not known at this time that
would
allow its position as a heavier homologue of gold to be confirmed.
Roentgenium was first observed in 1994 and several isotopes have been
synthesized since its first discovery. The most stable known isotope is
280Rg with a half-life of ~4 seconds.
Roentgenium was officially discovered by Peter Armbruster,
Gottfried Mnzenberg, and their team working at the Gesellschaft fr
Schwerionenforschung (GSI) in Darmstadt, Germany on December 8, 1994.
Only three atoms of it were observed (all 272Rg), by the cold fusion
between
nickel ions and a bismuth target in a linear accelerator.
In 2001, the IUPAC/IUPAP Joint Working Party (JWP) concluded that there
was insufficient evidence for the discovery at that moment in time.
The GSI team repeated their experiment in 2000 and detected a further
3 atoms. In their 2003 report, the JWP decided that the GSI team should
be
acknowledged as the discoverers.
The name roentgenium (Rg) was proposed by the GSI team in honor of the
German physicist Wilhelm Conrad Rntgen, and was accepted as a permanent
name on November 1, 2004. Previously the element was known under the
temporary IUPAC systematic element name unununium, Uuu.
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