| helium |
a colorless, odorless, tasteless gas (Helium becomes a liquid near absolute zero. Liquid helium is used to cool Jefferson Lab's accelerator components.)
출처: education.jlab.org/beamsactivity/6thgrade/vocabula...
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| helium |
Second lightest gas; dies not cause problems of narcosis to the same extent as seen with nitrogen, and is therefore used for very deep diving.
출처: www.empirescuba.com/Information/Divers_Glossary/di...
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| helium |
An inert gas. A colorless, monatomic element which is found to occur in dry air to the extent of only 0.000524 percent by volume. Helium is very light, having a molecular weight of only 4.003 and specific gravity referred to air of 0.138. Because helium is non-inflammable and has a lifting power 92 percent of that of hydrogen, it is widely used as the inflation gas for meteorological balloons.
출처: www.telemet.com/weather_gloss_h.htm
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| helium |
The second element in the periodic table, has 2 protons, 2 neutrons, and is a noble gas. It has an atomic mass of 4.00260 amu, and is inert. Helium was discovered in 1825 by Sir W. Ramsay of England, and N. Lenget and PT Cleve of Sweden. Helium melts at -272.2 degrees Celsius, and boils at -268.934 degrees Celsius. Helium has a density of 0.1785 g/L at STP (20 degrees C, 1 atm)
출처: www.wro.org/ras/glossary/g-i.htm
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| helium-neon laser |
A continuous wave laser that contains a mixture of helium and neon gases and emits red coherent light. It is only used to record subjects that do not move. It is manufactured to various power ranges, from 0.5 to 50 milliwatts. Because it is reasonably priced, this type of laser is commonly used by artists and amateurs.
출처: muse.jhu.edu/journals/leonardo/v034/34.4poissant.h...
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