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Introduction to Nanosensors
Published in Vinod Kumar Khanna, Nanosensors, 2021
The number of protons in the nucleus of an atom of an element is its atomic number (Z). The total number of protons and neutrons in the nucleus of an atom gives its mass number, atomic weight (A), or relative atomic mass. It is the ratio of the average mass per atom of the naturally occurring form of an element to 1/12th the mass of a carbon-12 isotope; an isotope is one or more atoms of an element having the same atomic number but a different atomic weight. One-twelfth the mass of a carbon-12 atom is called the atomic mass unit (amu) and is = 1.66033 × 10−27 kg.
Water/Wastewater Math Operations
Published in Frank R. Spellman, Handbook of Water and Wastewater Treatment Plant Operations, 2020
Key Point: Molecular weight is the weight of one molecule. It is calculated by adding the weights of all the atoms that are present in one molecule. The units are atomic mass units (amu). A mole is a gram molecular weight, that is, the molecular weight expressed in grams. The molecular weight is the weight of one molecule in daltons. All moles contain the same number of molecules, Avogadro’s number, equal to 6.022 × 1023. The reason all moles have the same number of molecules is because the value of the mole is proportional to the molecular weight.
Periodic Property
Published in Mihai V. Putz, New Frontiers in Nanochemistry, 2020
Francisco Torrens, Gloria Castellano
The atomic mass of an element is the average mass of an atom in a conventional sample of the element and is expressed in atomic mass units (amu) (Gray, 2009). The amu is defined as the 1/12 part of the mass of a 12C-atom. One amu is the mass of a proton or a neutron, so the atomic mass of an element is approximately equal to the total number of protons and neutrons in the nucleus. The relationship between the atomic mass and 1 amu is called atomic weight. However, the atomic weights of some elements are not integers. In the case that a conventional sample of the element includes two or more natural isotopes (Soddy, 1912), the weighted average of the isotopes masses justifies the fractional value of the atomic mass.
Extraction of spin-averaged rovibrational transition frequencies in HD+ for the determination of fundamental constants
Published in Molecular Physics, 2023
J.-Ph. Karr, Jeroen C. J. Koelemeij
Let us briefly describe Adjustment 1. It includes the 2018 CODATA value of electron's relative atomic mass, for which no new measurement has been reported since then. For the proton relative atomic mass, we use the value of from the latest (2020) Atomic Mass Evaluation (AME) [36, 37], corrected for the electron mass and for the theoretical binding energy. This value takes into account recent high-precision Penning trap data [5, 6], except for a very precise measurement of the deuteron-to-proton mass ratio, , performed in 2021 [7]. We thus also include the latter, together with the value of the deuteron mass deduced from the 2020 AME value of (again corrected for the electron mass and the binding energy), improving the proton mass determination. Adjustment 1 thus comprises N = 4 input data and M = 3 adjusted parameters, the relative atomic masses of the electron, proton and deuteron.
Charging effect induced by electron beam irradiation: a review
Published in Science and Technology of Advanced Materials, 2021
Z.J. Ding, Chao Li, Bo Da, Jiangwei Liu
where is the density of SiO2 and is the Avogadro constant; and are the Mott’s differential cross-sections calculated by Equations (1) and (2) for the collision with a single Si- and O-atom, respectively; is the relative atomic mass, and and are the atomic ratios for Si and O elements in SiO2. It is seen that it low-energy electrons is more likely to experience large-angle elastic scattering.
Comprehensive simulation study on CT isotope imaging beyond the experiment on the 208Pb based on nuclear resonance fluorescence
Published in Journal of Nuclear Science and Technology, 2021
Hani Negm, Heishun Zen, Hideaki Ohgaki
represents the atomic attenuation along the beam-axis, while stands for the nuclear attenuation of NRF. L is the distance from the source to the transmission detector. denotes the effective mass number through the beam axis, the atomic mass of the IOI, the Avogadro’s number. is the atomic cross-section due to EM-process, k, e.g. Compton scattering, photoelectric effect, etc., while is the cross-section of the NRF transition line j of the ith isotope. On the other hand, when the IOI is off the beam-axis, the transmission factor of the off-resonance (), , can be expressed by: