Helium-4 makes up about one quarter of the ordinary matter in the universe by mass, with almost all of the rest being hydrogen. While nuclear fusion in stars also produces helium-4, most of the helium-4 in the Sun and in the universe is thought to have been produced during the Big Bang, known as "primordial helium". However, primordial helium-4 ...

氦-4，是氦的同位素之一，元素符號為 4 He。它的原子核由二顆質子和二顆中子所組成，其自旋量子數為0，是玻色子。氦-4是穩定同位素。其相對豐度是99.999863%。

El helio-4 (4 He) es un isótopo de helio no radiactivo y ligero. Es, de lejos, el más abundante de los dos isótopos de helio naturalmente presentes, formando aproximadamente el 99,99986 % del helio en la Tierra. Su núcleo es una partícula alfa, que contiene dos protones y dos neutrones.

Superfluid helium-4 (helium II or He-II) is the superfluid form of helium-4, an isotope of the element helium. A superfluid is a state of matter in which matter behaves like a fluid with zero viscosity.

Properties and data of the isotope 4 He. See also: list of Helium isotopes. Direct parent isotopes are: 5 He, 5 Li, 6 Be. The following table shows the atomic nuclei that are isotonic (same neutron number N = 2) and isobaric (same nucleon number A = 4) with Helium-4.

Helium-4 (also written 4 He) is an isotope of helium. It is the most common isotope of helium in the universe. Out of all the helium on the Earth, 99.99986% is helium-4. The nucleus (the center) of a helium-4 atom is also known as the alpha particle.

2022年5月3日 · The transition frequency of (n, ℓ) = (17, 16) → (16, 15) in pionic helium-4 is calculated to an accuracy of 4 ppb (parts per billion), including relativistic and quantum electrodynamic corrections up to O (R ∞ α 5). Our calculations significantly improve the recent theoretical values [Hori et al., Phys. Rev. A 89, 042515 (2014)]. In ...

Protect you data from corruption & loss with RAID redundancy and ECC memory. Helios4 is the perfect recipe of high speed interfaces to build a real NAS. The Marvell ARMADA® 388 is a robust energy-efficient System on Chip (SoC) with very powerful processing abilities especially suited for headless data processing, networking and storage.

2011年12月25日 · Sciffentists have discovered the heaviest antimatter nucleus: antihelium-4, which contains two antiprotons and two antineutrons. The new discovery is described in the Vol. 473 of Nature. <dE/dx> versus p/|Z| for negatively charged particles (left) and positively charged particles (right). The black curves show the expected values for each species.

Helio-4 (4 /sup> Él) es un isótopo estable del elemento helio. Es, con diferencia, el más abundante de los dos isótopos de helio naturales y constituye aproximadamente el 99,99986% del helio de la Tierra.