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Absolute Photoluminescence Quantum Yield of Phosphors
Published in Ru-Shi Liu, Xiao-Jun Wang, Phosphor Handbook, 2022
The sensitivity of the measurement system is fully calibrated for the spectral region from 250 to 950 nm using deuterium and halogen standard light sources. These standard light sources are calibrated in accordance with measurement standards traceable to primary standards (national standards) located at the National Metrology Institute of Japan. The primary measurement standards are based on the physical units of measurement according to the International System of Units (SI).
Fundamental concepts
Published in Bernard S. Massey, John Ward-Smith, Mechanics of Fluids, 2018
Bernard S. Massey, John Ward-Smith
Consider the variables distance, depth, height, width and thickness. These variables have different meanings, but they all have one feature in common – they have the dimensions of length. They can all be measured in the same units, for example metres. From these introductory considerations, we can move on to deal with general principles relating to the use of dimensions and units in an engineering context. The dimension of a variable is a fundamental statement of the physical nature of that variable. Variables with particular physical characteristics in common have the same dimensions; variables with different physical qualities have different dimensions. Altogether, there are seven primary dimensions but in engineering fluid mechanics just four of the primary dimensions – mass, length, time and temperature – are required. A unit of measurement provides a means of quantifying a variable. Systems of units are essentially arbitrary, and rely upon agreement about the definition of the primary units. This book is based on the use of SI units.
A disaggregated freight transport market model based on agents and fuzzy logic
Published in Transportmetrica B: Transport Dynamics, 2019
The environment recreates the conditions and characteristics of the context in which the agents operate. In the case of a freight transport system, the environment refers to the physical properties of the goods (such as size, weight or volume), the technological properties of the vehicles (such as capacity or speed) and the geographical characteristics of the region in question (e.g. distance). The units of measurement implemented in the model follow the metric system as defined by The International System of Units.