The results show that the curing activity was so greatly enhanced that the curing peak temperature decreased from 190 ℃ for the unmodified system to 120～140 ℃ for the modified systems, and the apparent activation energy of curing reaction decreased from 131 kJ/mol to 70～ 80 kJ/mol .
结果表明 ,经过改性的固化体系的固化反应活性明显提高 ,固化反应峰顶温度从未改性体系的 1 90℃降至 1 2 0～ 1 4 0℃ ,表观活化能从未改性体系的 1 31 k J/mol降至 70～80 k J/mol.
Temperature-programmed surface reaction (TPSR) was used to study the catalyst after O2 chemisorption in 4.8% H2/Ar. Only a peak on the TPSR spectra was observed, the lower the peak temperature, the higher the activity is. It suggests that the strength of O2 chemisovbed bond is also related to /the HDN activity.
According to the mathematical character of the peak of thermal analysis curve and by using of Coats-Redfern equation,the compensation effect having kinetics significance was discovered for a series of related reactions,if the peak tempertures of those reactions are close each other at certain expcriment conditions.
The results show that initial degradation temperature of PPVL film, the top temperature of DTG peak and the temination temperature of DTG peak, as well as the initial exothemal temperature and the top temperature of DTA peak change along with the vulcanization process.
When the concentration of acetic acid is increased, the crystallization temperature decreases, and the structure of microcrystals is transformed from disorder into order and crystallite becomes regular tetragonal system.
The data of the thermal decomposition of two complexes were determined in flow atmosphere of high purity nitrogen by differential scanning calorimetry (DSC) , the thermal decomposition course of them were composed of two exothermic peak, the temperature of them begin break were 497. 2 K and 491. 8 K, the temperature of peak top of them were 564. 4 K and 613. 2 K, 544.4 K and 615. 1 K, the enthalpy values of thermal decomposition were 2026 kJ/mol and 961. 2 kJ/mol,2596kJ/mol and 1 097 kJ/mol by DSC determined,respectively, result show complexes have higher thermal stability.
The possibility of reconstructing a two-peak temperature distribution by the proposed method is demonstrated.
Effect of orientation on the peak temperature of the yield-stress anomaly in single crystals of the Ni3Ge alloy
Temperature dependence of the yield stress τc(T) and shear stresses, as well as the orientation dependence of the peak temperature Tp of the yield-stress anomaly have been studied on single crystals of the Ni3Ge alloy.
The peak temperature Tp corresponds to the maximum in the τc(T) dependence.
It is shown that in the case of the above equality it is possible to describe the orientation dependence of the peak temperature Tp of the temperature anomaly of the yield stress in single crystals of Ni3Ge.
Diffusion of benzene, toluene and ethylbenzene in mordentie, ZSM-5 and HZSM-5 was studied by temperature programed desorption method, and effective diffusion coefficient and diffusion activity energy were measured.
Oxygen chemisorption capacities of four sulfided alumina-supported Mo-Ni catalysts were determined by static adsorption method at -78℃.A linear relationship between the low temperature O. chemisorption (LTOC) and residual nitrogen in oil product was observed. It indicates that the LTOC method can be used to distinguish the small difference in hydrodenitrogenation (HDN) catalyst activity. Temperature-programmed surface reaction (TPSR) was used to study the catalyst after O2 chemisorption in 4.8% H2/Ar. Only a...
Oxygen chemisorption capacities of four sulfided alumina-supported Mo-Ni catalysts were determined by static adsorption method at -78℃.A linear relationship between the low temperature O. chemisorption (LTOC) and residual nitrogen in oil product was observed. It indicates that the LTOC method can be used to distinguish the small difference in hydrodenitrogenation (HDN) catalyst activity. Temperature-programmed surface reaction (TPSR) was used to study the catalyst after O2 chemisorption in 4.8% H2/Ar. Only a peak on the TPSR spectra was observed, the lower the peak temperature, the higher the activity is.It suggests that the strength of O2 chemisovbed bond is also related to /the HDN activity. After hydrogen reduction, the ESR signal of the catalyst chemisorbed with O2 is the same as that before O2 chemisorption, therefore, no structure change takes place caused by O2 chemisorption.
The surface acidity of the ZSM-5 zeolite can be measured using a front-chromatograph carring in the organic base and combining with TPD technique. In the process of converting methonal to high octone number gasoline, the HZSM-5 catalyst appears in a strong acid peak at high temperature region as compared with Y-type and moderate zeolites. Along with the increase of regenarating times, the acid concentration on the HZSM-5 surface is gradually reduced and the strong acid peak is moved toward the lower temperature...
The surface acidity of the ZSM-5 zeolite can be measured using a front-chromatograph carring in the organic base and combining with TPD technique. In the process of converting methonal to high octone number gasoline, the HZSM-5 catalyst appears in a strong acid peak at high temperature region as compared with Y-type and moderate zeolites. Along with the increase of regenarating times, the acid concentration on the HZSM-5 surface is gradually reduced and the strong acid peak is moved toward the lower temperature region. Therefore, the aromatic content in the products is decreased. Based on the analytical procedures proposed in this study, the reasonable explanations for describing the reaction mechanism in the conversion of high octane value gasoline from methonal on HZSM-5 catalyst have been provided.
峰顶温度
peak temperature
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