Influence of Temperature on theF‐Center Absorption in Sodium Fluoride

1966 ◽  
Vol 44 (4) ◽  
pp. 1324-1326 ◽  
Author(s):  
Kwasi Amenu‐Kpodo ◽  
Theodore J. Neubert ◽  
Walter Youngblade
2019 ◽  
Vol 7 (01) ◽  
pp. 294-301
Author(s):  
Vianne Diana Huamán Baca ◽  
Alejandro pablo Pletickosich ◽  
Teófila Baca Carbajal

ResumenEl objetivo de esta investigación fue determinar la influencia de la temperatura en la concentración de fluoruro de sodio; la muestra estuvo conformada por 60 geles fluorados de un mismo lote y la validez de dos marcas: ‘Fluofar®’ en sus dos presentaciones (pH neutro y acidulado) y el ‘Fluorgel Maquira®’ en sus dos presentaciones (pH neutro y acidulado). De cada gel fluorado se obtuvieron cuatro muestras: para comprobar el pH, para determinar la concentración de fluoruro de sodio a temperatura ambiente, para fijar la concentración de fluoruro de sodio después de haber sido sometido a una temperatura de 8 °C durante tres meses, y para, determinar la concentración de fluoruro de sodio después de haber sido sometido a una temperatura de 20 °C durante tres meses.La determinación de concentración de fluoruro de sodio, se realizó mediante la técnica de destilación y titulación. Por los resultados obtenidos se concluyó: que el incremento de la temperatura influye en la disminución de la concentración de fluoruro de sodio —siendo estadísticamente significativa en los geles fluorados con pH ácido (geles acidulados) y, en los geles fluorados con pH neutro mantiene su concentración—, aún se incrementó la temperatura. La concentración de fluoruro de sodio, indicado por el fabricante, disminuyó significativamente al comparar con la concentración de fluoruro de sodio encontrado en el laboratorio.Palabras claves; Geles fluorados, concentración de fluoruro de sodio, temperatura, pHAbstractThe objective of this investigation was to determine the influence of temperature on the concentration of sodium fluoride; the sample consisted of 60 fluorinated gels from the same batch and validity of two brands: Fluofar ® in its two presentations (neutral and acidulated pH) and Fluorgel Maquira ® and its two presentations (neutral pH and acidulated). From each fluorinated gel four samples were obtained: to determine the pH, to determine the concentration of sodium fluoride at room temperature, to determine the concentration of sodium fluoride after having been subjected to temperature of 8 °C for three months, and to determine the concentration of sodium fluoride after having been subjected to temperature of 20 °C for three months.The determination of concentration of Sodium Fluoride was carried out by means of the distillation and titration. From the results obtained, it was concluded that the increase in temperature influences the decrease in the concentration of sodium fluoride -being statistically significant in fluorinated gels with acidic pH (acidified gels) and, in fluorinated gels with neutral pH, it maintains its concentration-, the temperature was still increased. The concentration of sodium fluoride, indicated by the manufacturer, decreased significantly when compared to the concentration of sodium fluoride found in the laboratory.


Author(s):  
T. Geipel ◽  
W. Mader ◽  
P. Pirouz

Temperature affects both elastic and inelastic scattering of electrons in a crystal. The Debye-Waller factor, B, describes the influence of temperature on the elastic scattering of electrons, whereas the imaginary part of the (complex) atomic form factor, fc = fr + ifi, describes the influence of temperature on the inelastic scattering of electrons (i.e. absorption). In HRTEM simulations, two possible ways to include absorption are: (i) an approximate method in which absorption is described by a phenomenological constant, μ, i.e. fi; - μfr, with the real part of the atomic form factor, fr, obtained from Hartree-Fock calculations, (ii) a more accurate method in which the absorptive components, fi of the atomic form factor are explicitly calculated. In this contribution, the inclusion of both the Debye-Waller factor and absorption on HRTEM images of a (Oll)-oriented GaAs crystal are presented (using the EMS software.Fig. 1 shows the the amplitudes and phases of the dominant 111 beams as a function of the specimen thickness, t, for the cases when μ = 0 (i.e. no absorption, solid line) and μ = 0.1 (with absorption, dashed line).


2010 ◽  
Vol 25 (1) ◽  
pp. 93-105 ◽  
Author(s):  
Daniel Żarski ◽  
Dariusz Kucharczyk ◽  
Wojciech Sasinowski ◽  
Katarzyna Targońska ◽  
Andrzej Mamcarz

1930 ◽  
Vol 64 (695) ◽  
pp. 570-574 ◽  
Author(s):  
Leo Ferry ◽  
N. I. Shapiro ◽  
B. N. Sidoroff

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