RADON的意思|RADON的解释-里氏词典

radon ['reidɒn]

n. 氡

[化] 氡Rn

[医] 氡(86号元素), 镭射气

radon

[ noun ]
a radioactive gaseous element formed by the disintegration of radium; the heaviest of the inert gasses; occurs naturally (especially in areas over granite) and is considered a hazard to health
<noun.substance>

Radon \Ra"don\ (r[=a]"d[o^]n), n. (Chem.)
An intensely radioactive gaseous element produced by the
radioactive decay of radium-226, which is the main isotope of
radium found in pitchblende. Chemically it is an inert noble
gas. Its atomic symbol is Rn. It has an atomic number of 86.
The radon isotope produced by decay of radium has an atomic
weight of 222.017, and this isotope decays by alpha emission
with a half-life of 3.82 days. Numerous other isotopes have
been observed, all radioactive and all having half-lives
shorter than that of radon-222. Radon was discovered by M.
and Mme. Curie, of Paris, in their studies of the radioactive
substances in pitchblende. Radon was originally called
{radium emanation} or {exradio}.
[PJC]

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.

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

2. Grand; stately; magnificent; splendid; as, a noble
edifice.

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.

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

{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.

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

Yet, even in these 'hot' spots, the level of radon can vary greatly between one house and its neighbour.
Officials of the housing agencies are largely unaware of radon problems. and are uncertain whether they have any legal responsibility, it said.
Dennis Hess, another neighbor, is one of those skeptical about the radon threat.
The EPA said Monday every home in the country should be tested for radon because contamination is wider spread than previously believed.
The legislation would mandate EPA to develop model construction standards and techniques for controlling radon levels in new buildings and to rate the values of various radon measuring devices and radon-abatement contractors.
The legislation would mandate EPA to develop model construction standards and techniques for controlling radon levels in new buildings and to rate the values of various radon measuring devices and radon-abatement contractors.
Some analysts have suggested that the increasing importance being placed on energy efficiency also may be increasing the tendency of radon, an odorless, radioactive gas given off by all soils, to concentrate indoors.
The silos emit radon and are suspected of leaking waste into groundwater.
Now, as lists of hazardous substances and potential liabilities grow well beyond asbestos and radon, some lenders feel the home mortgage may be the next big risk.
"Kaufman has not been involved with radon for 12 years," said Dave Cohen, the agency's chief press officer. "Since then, the agency has found building materials to be negligible.
The Environmental Protection Agency estimates that radon, an odorless and invisible gas caused by the natural breakdown of uranium in soil and rock, causes 5,000 to 20,000 cases of fatal lung cancer every year.
Using technical language, he lashed out at critics who contend that neutrons allegedly generated by fusion in the experiment may really have come from naturally occurring radon gas and radiation in the Utah laboratory.
The House-passed bill would require EPA to conduct a national survey of school buildings and advise local education agencies about ways of reducing high concentrations of radon.
In September, the Public Health Service issued a national health advisory warning of radon dangers and the two agencies urged testing of every home where people live on the second floor or below.
The service said it is launching a more extensive radon testing program and that it would take "quick corrective action" at the facilities where the high gas levels have been found.
Radon levels in Watras' home of 800 times the concentration deemed hazardous first alerted environmental officials and residents of southeastern Pennsylvania to the danger of indoor radon concentration.
But remember that radon does harm only through exposure over many years.
"Based on measurements taken in 3,000 schoolrooms in 16 states, it appears that elevated levels of radon gas can be found in schools throughout the United States," Reilly said.
In addition to smoking, risk factors include exposure to radon, radiation, asbestos, arsenic and some chemicals.
Legislation pending in Congress would require inspections of public schools and set a long-term goal of making air equally low in radon indoors and outdoors.
Bush called for a national survey of schools in 1990 to detect and get rid of radon, and also for "strict standards" covering manufacturers who use lead in development of consumer products.
In recent years, however, public health officials have warned of the hazard of radon gas filtering into the basements of homes built over radium deposits.
The agency released test results showing that in eight states, about one-fourth of 11,000 randomly tested homes had radon readings considered unhealthy.
Last week's call for home tests said homeowners should find the radon source and try to reduce it if indoor contamination is above 4 picocuries per liter of air.
The Environmental Protection Agency says radon may cause from 5,000 to 20,000 lung-cancer deaths annually.
The service declined to speculate on why the radon levels at the two Colorado facilities and on Guam were unacceptably high.
They used to be nice soft sand, but now they crunch underfoot as you walk." Thirty dogs will have radon detectors attached to their collars as part of a study into the effects of the odorless gas.
Overall, said the EPA, about one-fourth of the 37,000 homes tested in 25 states so far have shown unhealthy indoor radon levels.
A preliminary report by the Environmental Protection Agency on radon contamination in schools was based on tests at 130 schools in the following communities.
Authorities have estimated that indoor concentrations of radon are responsible for as many as 20,000 lung cancer deaths annually.

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