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Red dwarfs [[Nuclear fusion|fuse]] [[hydrogen]] to [[helium]] via the [[Pp chain|proton-proton (PP) chain]]. Due to the low temperature ...]] model predicts the first generation of stars should have only hydrogen, helium and [[lithium]]. If such stars included red dwarfs, they should still be ob

...egularities that were observed in the spectra of atomic [[hydrogen]] and [[helium]]. Initially they thought that electrons rotate physically about an axis, h

...the next rigid airship to enter Navy service, was at first filled with the helium from the ''Shenandoah'' until more could be procured. ...men who would handle and supply the airship were added; facilities for the helium, [[gasoline]], and other supplies necessary for ''Shenandoah'' were built;

or to a helium isotope and emit a neutron:

{{r|Helium}}

...he looming war prevented German access to the required large quantities of helium, leading to the conversion of the Hindenburg to a hydrogen design. However

*Monatomic elemental gases: [[helium]] (He), [[neon]] (Ne), [[argon]] (Ar), [[krypton]] (Kr) and [[xenon]] (Xe) ...ve extremely low reactivity. The six naturally occurring noble gases are [[helium]] (He), [[neon]] (Ne), [[argon]] (Ar), [[krypton]] (Kr), [[xenon]] (Xe), an

...4He) (24% of total mass) and trace amounts of the isotopes deuterium (2H), helium-3 (3He) and lithium (7Li). Subsequently the interstellar medium within gala

...crease can be obtained by cooling the electronic components to near liquid helium temperatures, which greatly decreases electronic noise.

...electrodynamics]], the physics of the superfluidity of supercooled liquid helium, and particle theory. His work on quantum electrodynamics made him a joint

.... Pierce]] in command. The airship was also switched over from hydrogen to helium gas, which reduced payload but improved safety.

...ft "> 2 <td> [[Helium|He]] <td width="5%" > [[Helium/Atomic mass|{{:Helium/Atomic mass}}]] <td width="15%"> <td align="left "> 39 <td> [[Yttrium|

...bacterial strains or sperm samples. It is also used, usually with liquid helium, to cool superconducting magnetic materials for a variety of instruments in

...f our Sun can continue to burn each element synthesised in turn, hydrogen, helium, then [[carbon]], [[oxygen]], [[silicon]] and so forth until they are left

...e day you walk into a laboratory and there are all these pipes, and liquid helium is flowing, and currents are coming in and out with complicated wiring, and

...pe within a teletherapy unit; x-rays, electrons, protons, alpha particles (helium ions) and heavy charged ions, produced by particle acceleration; and neutro

*Other gases: [[nitrogen]] (N₂) and [[helium]] (He). ...distillation|distillation]]. This process can be modified to also recover helium, if desired.

...a very active variable star. As a star of low mass it converts hydrogen to helium very slowly compared to our own star. Sol. This slow conversion creates a t

|align=center| [[Helium|He]] ||align=center| 2702.7 ||align=center| 3.7 E-4||align=center| 14.97 E4 ...b>2</sub>]] || align=center| [[Nitrogen|N₂]] || align=center| [[Helium|He]] || align=center| [[Neon|Ne]] || align=center| [[Argon|Ar]] || align=ce

...a particles produced per second and one only has to measure the volume of helium gas produced per unit of time to know the number of atoms per volume, i.e., ...pp. 586-604 (1911)</ref> The first experiment gave 6.58 mm³ of helium gas at 0°C and 760 mm pressure, while the second gave gave 10.38 mm<sup>3<

...ments using a sheet of gold foil through which were fired alpha particles (helium nuclei containing two positive charges)<ref> see [[Alpha decay]]</ref><ref> ...is in fact a stream of particles, as Rutherford discovered later in 1908, helium atoms without their two electrons. Beta radiation is a stream of electrons.

<tr><td> He <td> [[Helium]] <td align="right"> 2

...m takes place in this environment, they claim the main product is ordinary helium and heat, which are produced in the same ratio as they are with plasma fusi ...heat and helium appear to be correlated, but the nuclear process producing helium is still to be determined.

<tr><td>2 <td>He <td>[[Helium]] <td bgcolor="#D0D0D0">2 <td>

...ic meter vs 1.0 kg per cubic meter at sea level). The primary advantage of helium is that it non-flammable whereas hydrogen burns readily in air. ...United States (until then the sole producer) was also unwilling to export helium because it was rare and was considered a strategic material. However, moder

|align=center| [[Helium|He]] ||align=center| 2702.7 ||align=center| 3.7 E-4||align=center| 14.97 E4 ...b>2</sub>]] || align=center| [[Nitrogen|N₂]] || align=center| [[Helium|He]] || align=center| [[Neon|Ne]] || align=center| [[Argon|Ar]] || align=ce

...t stars of spectral class ''F'' or ''G'' that are rich in [[carbon]] and [[helium]] content but poor in [[hydrogen]]. ...relatively low mass star exhausts the hydrogen in its core and starts the helium-to-carbon conversion in its interior instead.

...extremely low abundance of metals, or any element heavier than hydrogen or helium, and is very old; Weiss calculates an age of roughly 10 billion years. It i ...ar too small and irradiated to hold onto its primordial [[Hydrogen]] and [[Helium]] envelope. However, the composition of the planet varies greatly between t

...bundant element in the universe,<ref>In the following order: hydrogen (H), helium (He), and oxygen (O) and carbon (C)</ref> and it is literally the building

...atom of that element. Thus, the first six chemical elements, hydrogen, [[helium]], [[lithium]], [[boron]], [[nitrogen]] and [[carbon]] have 1, 2, 3, 4, 5 a

...23, p. 77-88.</ref> and Strutt<ref>Strutt R.J., 1909, The accumulation of helium in geologic time III. Proceeding of the Royal Society of London A, v. 83, p

...1.3 and 0.69 g/cc, respectively. Composed mainly of the gases hydrogen and helium. ...ammonia, with a small rocky core and an atmosphere of mostly hydrogen and helium.

It is composed largely of [[hydrogen]] and [[helium]]. Jupiter's strong internal heat creates a number of semi-permanent featu

'''p.11''' "The off-gas processing system uses helium sweep gas to entrain Xe and Kr gasses, passing them slowly through the off- ...ction in the nickel creating helium gas in the nickel. Annealing makes the helium migrate to grain boundaries, making it more brittle. Also not limiting."<br

...yers of the atmosphere. Neptune is comprised predominantly of hydrogen and helium. However, its methane component reaches the upper atmosphere absorbing red

...ations of matter at low temperatures which led to the production of liquid helium <td rowspan="1"> For theories for condensed matter, especially liquid helium

...o use [[hydrogen]] as the lift gas, despite the fact that hydrogen, unlike helium, is extremely flammable.<ref name="botting"> Botting 2001, p. 249-251.</ref ...d fire accidents had never occurred on civil zeppelins, so the switch from helium to hydrogen did not cause much alarm. Hydrogen also gave the craft about 8%

...a process that synthesises [[helium]]. When the hydrogen is consumed, the helium is then burned and that in turn synthesises carbon. To continue to burn fue

...red and tested. On September 19th (during a short period without beam), a helium enclosure was punctured due to the quench of a superconductor during electr

...d to either anti-inflammatory treatment and splinting after eight weeks or Helium-Neon laser treatment after six months" according to a [[meta-analysis]] by

<tr><td>[[Helium]]-3</td><td>³He</td><td>-1/2</td><td> - </td>

...ica]]'' noting that the almost complete absence of elements heavier than [[Helium]] in the early Universe meant stars could be much more massive than stars t

The atmosphere is composed of mainly of [[hydrogen]] and [[helium]] and has a temperature of about -216 °C.<ref> -357 °F; 57 K</ref> Its at

...distribution of the light nuclear isotopes hydrogen, deuterium, helium-3, helium-

These magnetometers require cooling with liquid [[helium]] (4.2&nbsp;K) or liquid [[nitrogen]] (77&nbsp;K) to operate, hence the pac

...compose dark matter then the early universe would have had to produce more helium and deuterium than could possibly exist. Possible types of DM are:

...etre as 1 579 800.762046±(3.3 &times;10^&minus;5) wavelengths of helium-neon laser light in vacuum, for example, and converting the wavelengths in ...tre, and any [[partial vacuum]] can be used, or some inert atmosphere like helium gas, provided the appropriate corrections for refractive index are implemen

...r hydrogen, [[lithium]], [[beryllium]], and [[borium]], which strive for a helium configuration of two electrons (a duplet), it means that most atoms try to ...In the first molecule (methane, CH₄) the hydrogen atoms have a helium electronic configuration (are surrounded by two electrons) and the carbon h

...o the [[liquefaction]] of [[hydrogen]] by [[James Dewar]] in 1898 and of [[helium]] by [[Heike Kamerlingh Onnes]] in 1908.

...the infamous Hindenburg disaster in 1937. Airships now use helium instead. Helium is chemically inert, so safer than hydrogen, but also more expensive and he

...o the [[liquefaction]] of [[hydrogen]] by [[James Dewar]] in 1898 and of [[helium]] by [[Heike Kamerlingh Onnes]] in 1908.

...oons, or "cells", contained the [[lighter-than-air]] gas [[hydrogen]] or [[helium]]. Non-rigid airships do not have multiple gas cells. Motive power was prov ...in technology considerably, and was intended to be filled with [[inert]] [[helium]].

...]] of 87.74 years and decays to uranium-234 by emitting &alpha;-particles (helium nuclei).

...cal elements, even if they do not recognize them as such. They include: [[helium]] (He), used to make party balloons float; [[lithium]] (Li), used to make b ...ericium]] <td align="right"> 95 <td width="15%"><td>He<td width="5%" >[[Helium]] <td align="right"> 2<td width="15%"> <td>Pu <td width="5%" >[[Plut

...f [[noble gas]]es, first observed (1908) by [[Heike Kamerlingh Onnes]] for helium, were very puzzling, as these effects could not be explained at all by cla ..., even for [[noble gas]] atoms. In fact, the dispersion force explains why helium gas can be liquefied. The dispersion force is often explained as due to an

|[[Helium]]|| align="center"|He|| align="center"|0.000520|| align="center"|5.20

...ore, they are inflated exclusively with the non-flammable [[noble gas]] [[helium]].

...ning out" of droplets of helium deep in Saturn's interior, the droplets of helium releasing heat by friction as they fall down through the lighter hydrogen.

...lure, there is a gap between the fuel and cladding. The gap is filled with helium gas for thermal bonding. If burnup is too high, however, the swelling and/o

<tr><td>[[Helium]]-3</td><td>³He</td><td>-1/2</td><td> - </td>

...abundant [[Chemical element|element]] in the universe (after hydrogen and helium) and the most abundant element of the [[lithosphere]] (about 47% of [[Earth

| 2 || He || [[helium]]

...erred to as pentanes⁺), elemental [[sulphur]], and sometimes [[helium]] and [[nitrogen]]. *Other gases: [[nitrogen]] (N₂) and [[helium]] (He).

...erred to as pentanes⁺), elemental [[sulphur]], and sometimes [[helium]] and [[nitrogen]]. *Other gases: [[nitrogen]] (N₂) and [[helium]] (He).

...ults. For an atom that only has occupied ''s'' orbitals, like hydrogen and helium, polarization functions start at ''l'' = 1. For atoms such as boron with o

...gether than in a gas, so are considerably denser than gases such as air or helium. ...e around 10 times denser than water, which is 800 times denser than air. [[Helium]] is roughly 1/7 the density of air.

...>4</sub>]] oxidizer and [[MMH]] fuel. They were pressurized by 0.5 kg of [[helium]] stored at 28.6 MPa in two tanks. The central tunnel housed the service propulsion engine and its two helium pressurant tanks. The engine used [[Aerozine 50]] ([[hydrazine]]/UDMH) fuel

...ly by a few centimetres in air or a piece of paper, and is equivalent to a helium nucleus. Beta radiation can be blocked by an aluminium sheet just a few mil

A water content reduction purification stage using HF and helium sweep gas was specified to run at 400&nbsp;°C. Oxide and sulfur contaminat ...es in excess of 750&nbsp;°C); better electric conversion efficiency than a helium-cooled VHTR operating in similar conditions; [[passive nuclear safety|passi

...]</ref> the liquefaction of [[gases]] (such as [[oxygen]], [[nitrogen]], [[helium]], [[argon]] and [[krypton]])<ref>[http://www.nzic.org.nz/ChemProcesses/pro

...nanoscale device]]s. Also, as the temperature is lowered to absolute zero, helium remains a liquid, rather than freezing to a solid, owing to the irremovable

Consider, as an example, the excited [[helium]] atom in the [[atomic electron configuration]] 2''p''3''p''. By the [[Angu

...mpose dark matter then the early universe would have had to produce more [[helium]] and [[deuterium]] than could possibly exist—not enough room for all of

...the core. The resulting [[red giant]] enjoys a brief life span before the helium fuel is in turn consumed. Very massive stars can also undergo a series of s

The [[quantum gas]]es [[hydrogen]], [[helium]], and [[neon]] do not conform to the corresponding-states behavior and the

The [[quantum gas]]es [[hydrogen]], [[helium]], and [[neon]] do not conform to the corresponding-states behavior and the

Calculations of the ratios of hydrogen and helium within the Sun suggest it is halfway through its life cycle. It will event ...85 | year=1973 | pages=477–498 }}</ref> Elements heavier than hydrogen and helium were formed in the cores of ancient and exploding stars, so the first gener

...on of [[Gas|gases]] such as [[hydrogen]], [[oxygen]], [[nitrogen]], and [[helium]]), and other low-temperature processing.

...orbital approximation can be extended to understand the other atoms e.g. [[helium]], [[lithium]] and [[carbon]].

...lei of lighter elements (e.g., hydrogen isotopes) into a heavier one (e.g.,helium).

|[[Helium]]|| align="center"|He|| align="center"|0.000520|| align="center"|5.20

...orbital approximation can be extended to understand the other atoms e.g. [[helium]], [[lithium]] and [[carbon]].

...as-cooled Reactor|High Temperature Gas-cooled Reactors]] (HTGRs) use inert helium gas as a coolant and can provide temperatures even higher than MSRs. These

...d the lid on, then dewatered completely, vacuum dried, and backfilled with helium for corrosion control. TSC was then transferred from the transfer cask to t

...med. It is normal to fill the gap between the fuel and the cladding with [[helium]] gas to permit better thermal contact between the fuel and the cladding. D

...ub>), any residual water liquid or vapor, [[mercury]], [[nitrogen]], and [[helium]] which could cause difficulty downstream. (See the block flow diagram of t

[[Gas-cooled fast reactor]]s have been the subject of research commonly using helium, which has small absorption and scattering cross sections, thus preserving

* [[Helium]]

...ke atom|hydrogen atom]] are the most important representatives. Even the [[helium]] atom, which contains just one more electron than hydrogen, defies all att

...olutions that developed included the use of [[hydrogen]], [[argon]], and [[helium]] as welding atmospheres.<ref name=Cary/> During the following decade, furt