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atomic mass

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Series: ASM Desk Editions
Publisher: ASM International
Published: 01 December 1998
DOI: 10.31399/asm.hb.mhde2.a0003083
EISBN: 978-1-62708-199-3
... Abstract Chemical elements are the basic chemical substances; that is, they cannot be decomposed by chemical change or made by chemical union. These elements follow a periodic pattern related to the atomic mass of each that allows them to be arranged into a convenient table. This article...
Series: ASM Handbook
Volume: 10
Publisher: ASM International
Published: 15 December 2019
DOI: 10.31399/asm.hb.v10.a0006651
EISBN: 978-1-62708-213-6
... time-of-flight mass spectrometer. Inductively coupled plasma and thermal ionization MS provide atomic information, and direct analysis in real-time and matrix-assisted laser-desorption ionization MS are used to analyze molecular compositions. The article describes various factors pertinent to...
Series: ASM Handbook
Volume: 10
Publisher: ASM International
Published: 15 December 2019
DOI: 10.31399/asm.hb.v10.a0006641
EISBN: 978-1-62708-213-6
... significantly. ICP-MS is more sensitive than the established atomic optical emission and atomic absorption spectrometers. ICP-MS analysis is also a more quantitative method compared with spark (or arc) source mass spectrometry, glow discharge mass spectrometry, secondary ion mass spectrometry, and other...
Series: ASM Handbook
Volume: 10
Publisher: ASM International
Published: 15 December 2019
DOI: 10.31399/asm.hb.v10.a0006683
EISBN: 978-1-62708-213-6
...-vacuum (UHV) environment. The transfer of momentum from the impinging primary ions to the sample surface causes sputtering of surface atoms and molecules. Some sputtered species are ejected with positive and negative charges, termed secondary ions, which are mass analyzed using a double-focusing mass...
Series: ASM Handbook
Volume: 10
Publisher: ASM International
Published: 15 December 2019
DOI: 10.31399/asm.hb.v10.a0006664
EISBN: 978-1-62708-213-6
... the vacuum system ( Ref 4 ). Typical operation of electron ionization MS uses a beam of electrons with a potential of 70 eV. This has been established as the energy required to efficiently create ions in a reproducible way for organic molecules with sizes < 1000 atomic mass units (amu, or...
Series: ASM Handbook
Volume: 10
Publisher: ASM International
Published: 15 December 2019
DOI: 10.31399/asm.hb.v10.a0006648
EISBN: 978-1-62708-213-6
... an argon plasma. Helium appears to be a strong candidate to improve the ionization of the aforementioned elements, because it has a first-ionization potential of 24.5 eV and two metastable levels at 19.82 and 20.62 eV. However, due to the low mass of the helium atoms, it produces significantly lower...
Series: ASM Handbook
Volume: 10
Publisher: ASM International
Published: 15 December 2019
DOI: 10.31399/asm.hb.v10.a0006663
EISBN: 978-1-62708-213-6
... applications of gas mass spectrometry. gas analysis mass spectrometry Gas analysis by mass spectrometry, or gas mass spectrometry, is a general technique using a family of instrumentation that creates a charged ion from a gas phase chemical species (atomic or molecular...
Series: ASM Handbook
Volume: 10
Publisher: ASM International
Published: 15 December 2019
DOI: 10.31399/asm.hb.v10.a0006653
EISBN: 978-1-62708-213-6
... ion, such as lanthanum(III) at sufficiently high concentration (e.g., 1% by mass) ( Ref 15 ). This enables formation of the respective lanthanum salts, thus allowing the calcium to form either the hydroxide or oxide, which is more efficiently atomized to yield gaseous calcium atoms. Another approach...
Series: ASM Handbook
Volume: 10
Publisher: ASM International
Published: 15 December 2019
DOI: 10.31399/asm.hb.v10.a0006658
EISBN: 978-1-62708-213-6
... its resonance frequency (Ref 5). When the vibrating cantilever begins to interact with the surface, the vibration amplitude of the cantilever will decrease ( Fig. 11 ). As the amplitude decreases, there is a slight change in the resonance of the cantilever, because the effective mass of the cantilever...
Book Chapter

By P.S. Grant
Book: Casting
Series: ASM Handbook
Volume: 15
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.hb.v15.a0005225
EISBN: 978-1-62708-187-0
... process that always produces a wide range of droplet diameters. The article schematically illustrates typical log-normal droplet diameter probability density distribution on a mass or volume basis obtained by gas atomization. It also illustrates the changes in solid fraction during the spray casting...
Book: Casting
Series: ASM Handbook
Volume: 15
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.hb.v15.a0005208
EISBN: 978-1-62708-187-0
... Abstract This article begins with balance equations for mass, momentum, energy, and solute and the necessary boundary conditions for solving problems of interest in casting and solidification. The transport phenomena cover a vast range of length and time scales, from atomic dimensions up to...
Series: ASM Handbook
Volume: 23
Publisher: ASM International
Published: 01 June 2012
DOI: 10.31399/asm.hb.v23.a0005685
EISBN: 978-1-62708-198-6
... devices. The methods include light microscopy, scanning electron microscopy, atomic force microscopy, energy-dispersive x-ray spectroscopy, Auger electron spectroscopy, secondary ion mass spectrometry, x-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and Raman spectroscopy...
Series: ASM Desk Editions
Publisher: ASM International
Published: 01 December 1998
DOI: 10.31399/asm.hb.mhde2.a0003253
EISBN: 978-1-62708-199-3
... secondary ion mass spectroscopy surface analysis transmission electron microscopy X-ray photoelectron spectroscopy A NUMBER OF METHODS can be used to obtain information about the chemistry of the first one to several atomic layers of samples of metals, as well as of other materials, such as...
Series: ASM Handbook
Volume: 5
Publisher: ASM International
Published: 01 January 1994
DOI: 10.31399/asm.hb.v05.a0001301
EISBN: 978-1-62708-170-2
... kinetic electron energy in electron volts, and a is the mean atomic distance in nanometers. The atomic mass number, M , the density, ρ, and Avogadro's number, N 0 , determine a = [ M /(ρ · N 0 )] 1/3 . Values of λ 0 are typically between 0.4 nm ( E ≈ 100 eV) and 2 nm ( E ≈ 1500 eV), meaning...
Series: ASM Desk Editions
Publisher: ASM International
Published: 01 December 1998
DOI: 10.31399/asm.hb.mhde2.a0003086
EISBN: 978-1-62708-199-3
... rapid. Mass characteristics include atomic weight and density. The atomic weight (or relative atomic mass ) is the ratio of the average mass per atom of an element to 1 12 of the mass of the atom of the nuclide 12 C. Atomic weights of the metallic elements are...
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006771
EISBN: 978-1-62708-295-2
... ejection of atomic and molecular ions. Greater than 90% of these secondary ions originate from the outermost one or two layers of the solid, thus defining TOF-SIMS as an extremely surface-sensitive technique. By applying a potential between the sample surface and the mass analyzer, the desorbed secondary...
Series: ASM Handbook
Volume: 4A
Publisher: ASM International
Published: 01 August 2013
DOI: 10.31399/asm.hb.v04a.a0005799
EISBN: 978-1-62708-165-8
... gas-steel interface. Diffusion of the absorbed carbon atoms in the steel occurs down the chemical potential gradient. According to the thermodynamics of irreversible processes ( Ref 17 ), the driving force for mass transfer during carburizing is the gradient in the carbon chemical potential...
Book: Casting
Series: ASM Handbook
Volume: 15
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.hb.v15.a0005189
EISBN: 978-1-62708-187-0
... interrelationship between phase diagrams and thermodynamics is presented. The article discusses processes that generally limit the rates of chemical processes. These include nucleation of the product phase and interphase mass transport. The article provides a discussion on the dissolution of alloy with melting...
Series: ASM Handbook
Volume: 22A
Publisher: ASM International
Published: 01 December 2009
DOI: 10.31399/asm.hb.v22a.a0005406
EISBN: 978-1-62708-196-2
... coupling of the CA to macroscopic calculation of heat, flow, and mass transfers in castings and applications to realistic casting conditions. microstructure solidification cellular automaton methods macrostructure grain structure castings heat transfers flow transfers mass transfers...
Series: ASM Handbook
Volume: 22A
Publisher: ASM International
Published: 01 December 2009
DOI: 10.31399/asm.hb.v22a.a0005437
EISBN: 978-1-62708-196-2
... Abstract This article presents the governing equations for moving a solidification front, based on the balance of mass, momentum, energy, and solute. It reviews how material properties and geometry can be analyzed in the context of the governing equations. The article provides several example...