排序方式: 共有13条查询结果,搜索用时 62 毫秒
1.
Résumé On a déterminé les paramètres cinétiques des réactions de décomposition de quelques combinaisons complexes des halogénures et pseudohalogénures de cobalt, nickel, manganèse, cuivre et cadmium, avec l'ammoniaque, la pyridine et des pyridines substituées. Pour les réactions d'ordre zéro, les valeurs des facteurs préexponentiels, calculées en considérant comme étape limitante la diffusion du composant volatil à travers la couche de la substance décomposée, concordent de façon satisfaisante avec celles déterminées expérimentalement.
Kinetic parameters were determined for the decomposition reactions of some com plexes of cobalt, nickel, manganese, copper and cadmium halides and pseudohalides with ammonia, pyridine and substituted pyridines. For the zero order reactions, the values of the pre-exponential factors calculated assuming as limiting step the diffusion of the volatile component through the layer of the decomposed substance, are in satisfactory agreement with the experimental values.
Zusammenfassung Es wurden die kinetischen Parameter der Zersetzungsreaktionen einiger Komplexe der Halogenide und Pseudohalogenide von Kobalt, Nickel, Mangan, Kupfer und Kadmium mit Ammoniak, Pyridin und substituiertem Pyridin bestimmt. Bei den Reaktionen von Null-Ordnung zeigten die preexponentiellen Koeffizienten, berechnet, indem für die limitierende Stufe die Diffusion des flüchtigen Bestandteils durch die Schicht der zersetzten Substanz betrachtet wurde, gute Übereinstimmung mit den experimentellen Werten.
, , , , , . . , . .相似文献
2.
D. Fatu 《Journal of Thermal Analysis and Calorimetry》1999,56(2):739-747
A method was devised to evaluate latent heats of vaporization from quasi-isothermal isobaric analysis data. The procedure
requires the recording of at least two diagrams: one for the investigated liquid, and the other for a standard liquid with
a known latent heat of vaporization. Use of the method to determine the heats of vaporization of some alcohols, with water
as standard liquid, led to results close to those previously reported in the literature.
The main advantage of the procedure consists in the fact that it requires only small amounts of sample (5–10 mg).
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
3.
Popescu C. Voicu I. Alexandrescu R. Morjan I. Dumitras D. Popescu M. Fatu D. 《Journal of Thermal Analysis and Calorimetry》1999,56(1):183-189
This paper reports on the synthesis of various iron oxides by the IR laser processing of different iron salts. X-ray diffraction
techniques were used to characterize the reaction products. Some differences in terms of crystallite size and isotropy between
these oxides and those obtained from the same salt by thermal means are described and explained.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
4.
Temperature-modulated DSC (TMDSC) measurements at reasonably high frequencies allow for the determination of base-line heat
capacity. In this particular case vitrification and devitrification of the rigid amorphous fraction (RAF) can be directly
observed. 0.01 Hz seems to be a reasonably high frequency for bisphenol-A polycarbonate (PC). The RAF of PC is established
during isothermal crystallization. Devitrification of the RAF seems to be related to the lowest endotherm. For PC the melting
of small crystals between the lamellae is expected to yield the lowest endotherm.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
A method is proposed for evaluation of the activation parameters for reactions which occur under non-isothermal conditions.
This method can discriminate between possible differential conversion functions. The proposed method, which was coded into
a software package available to the scientific community, is designed to solve an overdetermined systems of equations: dai/dt=k(Ti)f(ai) where i equations are to be considered (i can be the number of experimental points). Solution of this overdetermined system
with a pseudo-inverse matrix method furnishes the activation parameters and the parameters of the conversion function f(a).
Some examples of application of this method in non-isothermal kinetic analysis are presented.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
6.
7.
The results obtained by studying zinc oxide non-stoichiometrization are presented. The kinetic parameters values under nonisothermal conditions were calculated too. Both the nonstoichiometric zinc oxide composition and the kinetic parameter values are depending on the generating substances.
Zusammenfassung Die Ergebnisse der Untersuchungen der Nichtstöchiometrisierung von Zinkoxid werden vorgeführt.Die Werte der kinetischen Parameter unter nicht-isothermen Bedingungen wurden eben falls berechnet.Sowohl die nichtstöchiometrische Zusammensetzung des Zinkoxids als auch die Werte der kinetischen Parameter hängen von der das Phänomen auslösenden Substanz ab.
Résumé On présente les résultats d'une étude sur la formation d'oxyde de zinc non-stchiométrique. Les valeurs des paramètres cinétiques en conditions non-isothermes sont égale ment calculées. La composition de l'oxyde de zinc non-stchiométrique ainsi que les valeurs des paramètres cinétiques dépendent du composé de départ.
, , . .相似文献
8.
A. Bencovski A. Caraman D. Fatu E. Pop E. Segal Gh. Serban 《Journal of Thermal Analysis and Calorimetry》1973,5(4):427-444
Résumé On présente les résultats obtenus dans l'évaluation des paramètres cinétiques de la réaction de décomposition thermique de l'anhydride chromique déposé sur de l'alumine. Grâce aux données sur l'influence de la teneur en anhydride chromique et de la vitesse de chauffage sur les paramètres cinétiques, on obtient des conclusions sur les conditions d'obtention du catalyseur Cr2O3/Al2O3.
Results obtained in the determination of the kinetic parameters of the thermal decomposition of CrO3 on alumina are presented. The experimental data on the effects of CrO3 concentration and heating rate on the kinetic parameters are used to draw conclusions on the conditions of preparation of Cr2O3/Al2O3 catalysts.
Zusammenfassung Die bei der Bestimmung der kinetischen Parameter der thermischen Zersetzungsreaktion von CrO3 auf Aluminiumoxid-Träger erhaltenen Ergebnisse werden erörtert. Aus den Versuchsangaben über den Einfluß der Cr2O3-Konzentration und die Aufheizgeschwindigkeit auf die kinetischen Parameter werden Schlüsse bezüglich der Herstellungsbedingungen der Cr2O3/Al2O3-Katalysatoren gezogen.
, Cr3 . Cr2O3 , Cr2O3/l2O3.相似文献
9.
The thermal decomposition of thiobenzpiperidides and some derivatives containing substituents on the benzene nucleus was studied.
By thermal analysis was put in evidence the influence of the nature and position of the substituents on the decomposition
process.
Kinetic parameters in non-isothermal and quasi-isothermal conditions (CRTA) were calculated.
The chromatographic analysis, associated with mass spectrometry, proved that the initiation of the complex decomposition process
is the result of the polar bond break.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
10.
D. Fatu 《Journal of Thermal Analysis and Calorimetry》2001,65(1):213-220
The kinetics of gypsum dehydration in non-isothermal conditions with constant heating rate as well in quasi-isotherm, quasi-isobar regime, was investigated. The latter ones of these methods allowed putting in evidence the autocatalytic character of the dehydration, as well as the change of the activation energy with the conversion.The activation energy change was explained by the crystal growth and sample compaction observed by optical microscopy.Microscopic observations show that at higher conversions a compaction occur. This process is probably favoured by the accumulation of the water vapour from the dehydration (autogenerate atmosphere). These are the reason for step III characterised by higher activation.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献