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91.
G. Madhurambal P. Ramasamy P. AnbuSrinivasan S. C. Mojumdar 《Journal of Thermal Analysis and Calorimetry》2007,90(3):673-679
The kinetic parameters (reaction order, n, activation energy, E, pre-exponential factor, A, constant rate, k) for the dehydration step due to elimination of osmotic water and hydrogen-bounded water with the carboxylic groups, and
for the anhydrifying step owing to the dehydration of two neighboring (-COOH) groups, were determined under non-isothermal
conditions for some carboxylic resins with acrylic-divinylbenzene (DVB) matrix. The kinetic parameters were evaluated by means
of isoconversional methods from (TG/DTG) thermal analysis data. The results show a dependence of the apparent kinetic parameters
on the cross-linking degree, granulation, gel/macroporous matrix nature, exchange capacity and heating rate. 相似文献
92.
Summary Ru/g-Al2O3 catalyzed the dehydrogenation of alcohols to carbonyl compounds without employing hydrogen acceptor. The catalyst was readily
recovered from the reaction mixture and could be reused. 相似文献
93.
The conditions for obtaining periodic precipitation of cobalt(II) oxinate in agar-agar gel are investigated. The dependence of the nature of periodic precipitation on the concentrations of inner and outer electrolytes is studied in detail. The spacing law of Jablczynski and the time law of Morse and Pierce are verified in this system. The dependence of velocity constant (K) and the spacing coefficient (p) on the concentrations of inner and outer electrolytes has been studied. The velocity constant shows a nonlinear variation with the concentrations of the inner and outer electrolytes. The spacing coefficient (p) is inversely proportional to the concentrations of the inner and outer electrolytes. According to Shouji Shinohara's revised flocculation theory, the flocculation values are computed. The dependence of the flocculation value on the concentrations of the outer and inner electrolytes is studied. 相似文献
94.
95.
96.
GaAs epitaxial layers of high structural quality have been realised from Ga–As–Bi melt using liquid-phase epitaxy (LPE). LPE grown GaAs epitaxial layer using bismuth solvent on GaAs substrate has been found to be of good structural perfection as compared to layers using gallium solvent. The temperature-dependent PL spectra of GaAs layer, grown from Ga+Bi mixed solvent has shown that the use of bismuth does not change the band energy. ECV depth profile of heavily zinc-doped epitaxial layer shows uniform doping in the GaAs layer grown using gallium solvent as compared to the layer grown using bismuth solvent. 相似文献
97.
K. S. Raju M. Palaniswamy P. Ramasamy G. S. Laddha 《Crystal Research and Technology》1984,19(7):939-945
Linear arrays of dislocations (straight, terminating and curved) are observed on etching with 2% citric acid (002) cleavages of lithium carbonate (Li2CO3) single crystals, grown by zone melting technique. As the dislocations are non-uniformly spaced and disappear on successive etching, they may not be revealing low-angle grain boundary, nor slip traces as they are terminating and curved meaning crystallographically non-oriented. On the observation of experiments on successive etching and etching of matched pairs, it is concluded that the arrays of etch pits reveal dislocation walls (dislocation density 1.1 × 106 — 1.5 × 107 pits cm−2) probably created due to the localized thermal stresses released as a result of high temperature annealing of the crystal during growth. The implications are discussed. 相似文献
98.
Crystals of cholic acid have been grown in silica and tetramethoxy silane gels. Crystals grew with different morphology and Leisegang rings were also seen in some cases. Crystals were analyzed by X-ray, IR and microhardness studies. The grown crystals were found to be monohydrate and the hardness of the crystals were found to decrease with increase of load. 相似文献
99.
100.
The influence of temperature on periodic crystallisation of magnesium hydroxide in agar-agar gel has been studied. The increase
in velocity constant with temperature is attributed to the increase in the diffusion constant with temperature. The activation
energy for diffusion of aqueous ammonia is calculated from the temperature — velocity constant correlation. The solubility
of Mg(OH)2 decreases with temperature. The decrease in the spacing coefficient and fiocculation value of Mg(OH)2 with temperature is also explained because of the increase in temperature. Matalon and Packter’s equation correlating the
spacing coefficient and concentration of the inner electrolyte is suitably modified to satisfy the temperature dependence
of the spacing coefficient. 相似文献