Up until approximately 80 years ago, only black-body radiation (including natural sources) was available to illuminate our environment. To realise state-of-the-art lamps, TV sets, monitors, and medical scanners, took an enormous scientific and technical effort. Inorganic luminescent materials are key components, which were, are, and will be prerequisite to the functionality and success of many lighting and display systems. In this Highlight, a hundred years of inorganic luminescent material research are reviewed.

Inorganic Luminescent Materials: 100 Years of Research and Application

On the analysis of thermally stimulated processes

A new method for calculating activation energies and frequency factors from thermoluminescence and thermally stimulated current peaks is described. The validity of this method, as well as of most of the other known ones, is examined for a broad range of energies and frequency factors by the use of a computer. A combination of theoretical and empirical‐computational analysis is used to give corrected formulas for some of the previous methods, while only empirical corrections are given for some others. Apart from the maximum temperature, Tm, the new method uses the total half width ω=T2−T1, where T1 and T2 are the half‐intensity temperatures on the low‐ and high‐temperature side of the peak, respectively. For a first‐order peak with a frequency factor independent of temperature, the activation energy is given by E=2kTm(1.26 Tm/ω−1) where k is Boltzmann's constant. The frequency factor is found for this case to be s=[2β(1.26 Tm/ω−1)/(e2Tm)] exp(2.52Tm/ω) where β is the (linear) heating rate and e is 2.718. For the case where pre‐exponential factors depend on temperature as some power function and for second‐order glow peaks, similar formulas are developed for the calculation of activation energies. The relative advantages of the various methods are discussed both from the theoretical and experimental points of view. The method for distinguishing between first‐ and second‐order peaks is also discussed.

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On the Calculation of Activation Energies and Frequency Factors from Glow Curves

Thermoluminescence glow-curve deconvolution (GCD) functions are proposed for first, second and general orders of kinetics. The free parameters of the GCD functions are the maximum peak intensity and the maximum peak temperature , which can be obtained experimentally. The activation energy (E) and the order of kinetics (b) in the case of general order kinetics are the additional free parameters.

https://iopscience.iop.org/article/10.1088/0022-3727/31/19/037/pdf

Thermoluminescence glow-curve deconvolution functions for first, second and general orders of kinetics

We present a survey of over 50 representative problems in location research. Our goal is not to review all variants of different location models or to describe solution results, but rather to provide a broad overview of major location problems that have been studied, indicating briefly how they are formulated and how they relate to one another. We review standard problems such as median, center, and warehouse location problems, as well as less traditional location problems which have emerged in recent years. Our primary focus is on problems for which operations research-type models have been developed. Most of the problems we review have been formulated as optimization problems.

An overview of representative problems in location research

In this text, the authors offer an account of thermoluminescence (TL) and other thermally stimulated phenomena. Although most recent experimental results of TL in different materials are described in some detail, the emphasis is on general processes, and the approach is more theoretical.Thus , the details of the possible processes which can take place during the excitation of the sample, and during its heating, are analyzed. The methods for analyzing TL glow curves are critically discussed, and recommendations as to their application are made. Also discussed are the expected behaviour of these phenomena as functions of the experimental parameters, for example, the dose of excitation. The consequences concerning the main applications of TL (for example, radiation dosimetry) are also discussed in detail as well as the similarities and dissimilarities of other thermally stimulated phenomena, and the simultaneous measurements of the latter and TL.

Theory of thermoluminescence and related phenomena

(partial) Preface Introduction Thermoluminescence, thermally stimulated conductivity and thermally stimulated electron emission Thermally stimulated polarization and depolarization currents Thermogravimetry, differential thermal analysis and associated methods Other thermally stimulated processes Methods for evaluating parameters from thermally stimulated curves Data from a series of measurements Simultaneous measurements and complementary methods Application of the methods of analysis to experimental results - possibilities and limitations Applications Appendices References Subject index Author index

Analysis of thermally stimulated processes

Thermoluminescence and thermally stimulated current curves obeying general order kinetics laws are being investigated. For these cases, whose order is not necessarily first or second but rather may have some noninteger value, an effective method of calculating the activation energy is given. This method is based on measuring the temperature at the maximum of the glow peak and the half intensity temperatures. Numerical calculations for orders between 0.7 and 2.5, activation energies between 0.1 and 1.6 eV and frequency factors between 105 and 1013 sec−1 have been done using an I.B.M. 360 computer. The results reveal the general characteristics of these peaks and their dependence on the parameters. The new method for calculating the activation energy is also checked numerically.

Reuven Chen

Papers

Theory of thermoluminescence and related phenomena

On the analysis of thermally stimulated processes

Analysis of thermally stimulated processes

Glow Curves with General Order Kinetics

On the Calculation of Activation Energies and Frequency Factors from Glow Curves