Electron paramagnetic resonance and microstructural insights into the thermal behavior of simonkolleite nanoplatelets

2020 ◽  
Vol 22 (17) ◽  
pp. 9503-9512
Author(s):  
Arpad Mihai Rostas ◽  
Andrei Cristian Kuncser ◽  
Daniela Ghica ◽  
Alexandra Palici ◽  
Valentin Adrian Maraloiu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Experimental Data ◽  
Thermal Decomposition ◽  
Electron Paramagnetic Resonance ◽  
Thermal Behavior ◽  
Decomposition Process ◽  
Thermal Decomposition Process ◽  
Paramagnetic Resonance ◽  
Electron Paramagnetic

The thermal decomposition process of simonkolleite, at 500 °C was monitored by EPR and electron microscopy. The experimental data indicate that after an 1 h at 500 °C, three morphologies can be observed from the thermal decomposition of ZHC.

scholarly journals Thermal behavior and decomposition kinetics of rifampicin polymorphs under isothermal and non-isothermal conditions

2010 ◽  
Vol 46 (2) ◽  
pp. 343-351 ◽  
Author(s):  
Ricardo Alves ◽  
Thaís Vitória da Silva Reis ◽  
Luis Carlos Cides da Silva ◽  
Silvia Storpírtis ◽  
Lucildes Pita Mercuri ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Thermal Behavior ◽  
Melting Process ◽  
Decomposition Process ◽  
Stable Form ◽  
Thermal Decomposition Process ◽  
Mean Values ◽  
Conversion Level ◽  
Polymorphic Forms ◽  
Crystalline Forms

The thermal behavior of two polymorphic forms of rifampicin was studied by DSC and TG/DTG. The thermoanalytical results clearly showed the differences between the two crystalline forms. Polymorph I was the most thermally stable form, the DSC curve showed no fusion for this species and the thermal decomposition process occurred around 245 ºC. The DSC curve of polymorph II showed two consecutive events, an endothermic event (Tpeak = 193.9 ºC) and one exothermic event (Tpeak = 209.4 ºC), due to a melting process followed by recrystallization, which was attributed to the conversion of form II to form I. Isothermal and non-isothermal thermogravimetric methods were used to determine the kinetic parameters of the thermal decomposition process. For non-isothermal experiments, the activation energy (Ea) was derived from the plot of Log β vs 1/T, yielding values for polymorph form I and II of 154 and 123 kJ mol-1, respectively. In the isothermal experiments, the Ea was obtained from the plot of lnt vs 1/T at a constant conversion level. The mean values found for form I and form II were 137 and 144 kJ mol-1, respectively.

Theoretical Studies on the Gyromagnetic Factors and the Hyperfine Structure Constants for the Tetragonal Copper Center in KTaO3

2005 ◽  
Vol 60 (8-9) ◽  
pp. 615-618 ◽  
Author(s):  
Hui-Ning Dong
Keyword(s):  
Experimental Data ◽  
Electron Paramagnetic Resonance ◽  
Hyperfine Structure ◽  
Defect Structure ◽  
Electrostatic Repulsion ◽  
Theoretical Studies ◽  
Paramagnetic Resonance ◽  
Copper Center ◽  
Structure Constants ◽  
Electron Paramagnetic

The gyromagnetic factors g∥, g⊥ and the hyperfine structure constants A∥ and A⊥ of the tetragonal Cu2+ center in KTaO3 are theoretically studied in this work. Based on the analyses of the electron paramagnetic resonance results of this center, it is found that the impurity Cu2+ occupies the octahedral Ta5+ site, associated with a nearest-neighbouring oxygen vacancy VO along the C4 axis. Due to the electrostatic repulsion of VO, Cu2+ is displaced away from VO by ΔZ(≈ −0.29 Å ) along the C4 axis. The theoretical values of the g and A factors based on the above defect structure and the impurity displacement agreee reasonably with the experimental data.

scholarly journals Addendum

1993 ◽  
Vol 443 (1919) ◽  
pp. 623-624
Keyword(s):  
Experimental Data ◽  
Electron Paramagnetic Resonance ◽  
Editorial Comment ◽  
Debye Temperature ◽  
Royal Society ◽  
Paramagnetic Resonance ◽  
Electron Paramagnetic

Proc. R. Soc. Lond. A 419, 287–303 (1988) Electron paramagnetic resonance determination of Debye temperature By K. N. Shrivastava Editorial comment A dispute has arisen over this paper, with a request that an addendum be published. The Editor drafted a short addendum for consideration by Professor Shrivastava, who feels very strongly, however, that the addendum is both unnecessary and misleading and instead has proposed his own. The Editor has decided to publish the draft addendum along with that of Professor Shrivastava. The matter, so far as Proceedings of the Royal Society , series A, is concerned, is regarded as closed. Draft addendum Professor Shrivastava acknowledges the source of the experimental data used in tables 1–8, as follows. The data of tables 6 and 7 (except for the 300 K point) were taken from Wan et al . (1987). Portions of the data of tables 4 and 5 appeared first in Rubins (1986) and of table 8 in Drumheller & Rubins (1986). The remainder of the experimental data shown in tables 1, 2, 4, 5 and 8 was communicated by Dr R. S. Rubins.

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