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helium    音标拼音: [h'iliəm]
n. 氦



helium
n 1: a very light colorless element that is one of the six inert
gasses; the most difficult gas to liquefy; occurs in
economically extractable amounts in certain natural gases
(as those found in Texas and Kansas) [synonym: {helium}, {He},
{atomic number 2}]

Noble \No"ble\, a. [Compar. {Nobler}; superl. {Noblest}.] [F.
noble, fr. L. nobilis that can be or is known, well known,
famous, highborn, noble, fr. noscere to know. See {know}.]
1. Possessing eminence, elevation, dignity, etc.; above
whatever is low, mean, degrading, or dishonorable;
magnanimous; as, a noble nature or action; a noble heart.
[1913 Webster]

Statues, with winding ivy crowned, belong
To nobler poets for a nobler song. --Dryden.
[1913 Webster]

2. Grand; stately; magnificent; splendid; as, a noble
edifice.
[1913 Webster]

3. Of exalted rank; of or pertaining to the nobility;
distinguished from the masses by birth, station, or title;
highborn; as, noble blood; a noble personage.
[1913 Webster]

Note: Noble is used in the formation of self-explaining
compounds; as, noble-born, noble-hearted, noble-minded.
[1913 Webster]

{Noble gas} (Chem.), a gaseous element belonging to group
VIII of the periodic table of elements, not combining with
other elements under normal reaction conditions;
specifically, {helium}, {neon}, {argon}, {krypton},
{xenon}, or {radon}; also called {inert gas}.

{Noble metals} (Chem.), silver, gold, and platinum; -- so
called from their resistance to oxidation by air and to
dissolution by acids. Copper, mercury, aluminium,
palladium, rhodium, iridium, and osmium are sometimes
included.
[1913 Webster]

Syn: Honorable; worthy; dignified; elevated; exalted;
superior; sublime; great; eminent; illustrious;
renowned; stately; splendid; magnificent; grand;
magnanimous; generous; liberal; free.
[1913 Webster]


Helium \He"li*um\ (h[=e]"l[i^]*[u^]m), n. [NL., fr. Gr. "h`lios
the sun.] (Chem.)
An inert, monoatomic, gaseous element occurring in the
atmosphere of the sun and stars, and in small quantities in
the earth's atmosphere, in several minerals and in certain
mineral waters. It is obtained from natural gas in industrial
quantities. Symbol, He; atomic number 2; at. wt., 4.0026
(C=12.011). Helium was first detected spectroscopically in
the sun by Lockyer in 1868; it was first prepared by Ramsay
in 1895. Helium has a density of 1.98 compared with hydrogen,
and is more difficult to liquefy than the latter. Chemically,
it is an inert noble gas, belonging to the argon group, and
cannot be made to form compounds. The helium nucleus is the
charged particle which constitutes alpha rays, and helium is
therefore formed as a decomposition product of certain
radioactive substances such as radium. The normal helium
nucleus has two protons and two neutrons, but an isotope with
only one neutron is also observed in atmospheric helium at an
abundance of 0.013 %. Liquid helium has a boiling point of
-268.9[deg] C at atmospheric pressure, and is used for
maintaining very low temperatures, both in laboratory
experimentation and in commercial applications to maintain
superconductivity in low-temperature superconducting devices.
Gaseous helium at normal temperatures is used for buoyancy in
blimps, dirigibles, and high-altitude balloons, and also for
amusement in party balloons.
[Webster 1913 Suppl. PJC]



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  • Helium Browser
    Helium blocks all third-party cookies and does its best to prevent fingerprinting No extra steps are needed, and there are no biased exceptions — unlike other browsers
  • Helium - Wikipedia
    On Earth, it is relatively rare—5 2 ppm by volume in the atmosphere Most terrestrial helium present today is created by the natural radioactive decay of heavy radioactive elements (thorium and uranium, although there are other examples), as the alpha particles emitted by such decays consist of helium-4 nuclei
  • Helium | Definition, Properties, Uses, Facts | Britannica
    Helium is a chemical element, an inert gas of Group 18 (noble gases) of the periodic table The second lightest element, helium is a colorless, odorless, and tasteless gas that becomes liquid at -268 9 degrees Celsius
  • Properties and Applications of Helium | Springer Nature Link
    Helium was first discovered in the Sun in 1868 and later identified on Earth in 1895 Given its unique physical and chemical properties, helium has been a research hotspot for over a century, leading to the emergence of new phenomena, theories, and achievements
  • Helium - Element information, properties and uses | Periodic Table
    Element Helium (He), Group 18, Atomic Number 2, s-block, Mass 4 003 Sources, facts, uses, scarcity (SRI), podcasts, alchemical symbols, videos and images
  • Helium - Own the Air
    Helium replaces cell towers with small devices called Hotspots that provide affordable connectivity and expand coverage wherever people gather, work, and move Businesses and individuals host them, earn HNT for every connection, and create the world’s largest decentralized wireless network
  • Helium | He (Element) - PubChem
    Chemical element, Helium, information from authoritative sources Look up properties, history, uses, and more
  • About Helium - Bureau of Land Management
    Helium is an odorless, nontoxic, colorless, tasteless gas; it has a very low chemical reactivity and it is lighter than air These characteristics are why helium plays a prominent role in space exploration, national defense, scientific research, medical technology, high-tech manufacturing and energy programs
  • HELIUM AND RARE GASES - USGS Publications Warehouse
    Helium-3, which is a rare isotope of helium, was produced at one location in South Carolina via tritium decay Production data were withheld to avoid disclosing proprietary data Helium-3 was mainly used for neutron detectors, research, and quantum computing Rare gases are produced through fractional distillation in air separation units
  • Why the Iran war matters for the world’s helium supply | AP News
    The Iran war is tightening global tech supply chains by cutting off helium from Qatar, a key source of the gas used in advanced industries like chipmaking





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