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The helium dimer is a van der Waals molecule with formula He 2 consisting of two helium atoms. [2] This chemical is the largest diatomic molecule—a molecule consisting of two atoms bonded together. The bond that holds this dimer together is so weak that it will break if the molecule rotates, or vibrates too much.
A Helium analyzer is an instrument used to identify the presence and concentration of helium in a mixture of gases. In Technical diving where breathing gas mixtures known as Trimix comprising oxygen , helium and nitrogen are used, it is necessary to know the fraction of helium in the mixture to reliably calculate decompression schedules for ...
The integral unit allows single-handed operation, so the operator can use the other hand for personal security in challenging monitoring positions, but the two piece design allows easier manipulation of the detector, and is commonly used for alpha and beta surface contamination monitoring where careful manipulation of the probe is required or ...
Gas expansion pycnometer is also known as constant volume gas pycnometer. The simplest type of gas pycnometer (due to its relative lack of moving parts) consists of two chambers, one (with a removable gas-tight lid) to hold the sample and a second chamber of fixed, known (via calibration) internal volume – referred to as the reference volume or added volume.
In addition, when the helium discharge gas is doped with a suitable noble gas, such as argon, krypton, or xenon (depending on the desired cutoff point), the PDD can function as a specific photoionization detector for selective determination of aliphatics, aromatics, amines, as well as other species.
Helium–cadmium (HeCd) metal-vapor laser 325 nm, 441.563 nm Electrical discharge in metal vapor mixed with helium buffer gas. Printing and typesetting applications, fluorescence excitation examination (i.e. in U.S. paper currency printing), scientific research. Helium–mercury (HeHg) metal-vapor laser 567 nm, 615 nm
This is a heat resistance at the surface between the helium liquids and the solid body of the heat exchanger. It is inversely proportional to T 4 and the heat-exchanging surface area A. In other words: to get the same heat resistance one needs to increase the surface by a factor 10,000 if the temperature reduces by a factor 10.
One of the types of manipulators is balanced manipulator type MSP-250, controlled by the operator's hand. Such manipulators are used in various industries.