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Abstract
The literature reveals that the mechanisms of some solid-state dehydrations are more complicated than has been generally accepted. Reactions at a thin advancing reactant-product interface provide the geometric models on which the most widely employed rate equations are based. For some systems, this “thin interface” model is a simplification of observed behaviour. Elimination of water from crystallographic sites may occur to a significant extent within a much thicker zone of reactant towards which the active interface is progressing. Consequently the region of chemical change may not coincide with the region of structural transformation. Limited initial dehydration may occur across all crystal faces prior to the onset of a nucleation and growth process that is usually regarded as the dominant rate process in the dehydrations of many large crystals. Experimental observations for solid-state dehydrations are discussed and reaction mechanisms with different rate controlling processes are distinguished. Studies of dehydrations have contributed substantially to the theory of solid-state reactivity, and advances in understanding may have wider application to other solid-state reactants.
Mechanism of pain sensation development
A fájdalom neurofiziológiájának új eredményei az idegtudomány tükrében
Apkarian, V. A., Bushnell, C. M., Treede, R. és mtsai: Human brain mechanisms of pain perception and regulation in health and disease. Eur. J. Pain, 2005, 9 , 463–484. Treede R
Steps in a minefield
Some kinetic aspects of thermal analysis
Abstract
This paper is a review of some of the controversial kinetic aspects of thermal analysis, starting from the ‘šesták questions’ posed in 1979 and looking at developments in some areas since that time. Aspects considered include: temperature programmes and variations, models and mechanisms, kinetic parameters, distinguishability and extent of fit of kinetic models, complementary evidence for kinetic models, the Arrhenius equation and the compensation effect. The value of the ideas of non-isothermal kinetics in chemical education is emphasized.
mechanistic work has focused on chronic exercise behavior and its ability to induce neurogenesis, gliogenesis, angiogenesis, cerebral circulation, and growth factor production ( 8 , 28 , 29 , 31 , 40 , 42 ). Of interest herein are the mechanisms of acute
conditions, if the chemical mechanism of reaction is unknown and not really important, Determine and describe the kinetic mechanism if the chemical mechanism of reaction is unknown or partially unknown. The first task is a more technical task and
Binding mechanisms of nano-baskets toward alkali metals
Isothermal titration calorimetric study
systems. The other hosts:guests interactions using ITC has been reported in the literatures [ 7 , 8 ]. Not only ITC has been used to determine the binding stoichiometry and affinity [ 9 ] as well as the inclusion mechanism of supramolecular nanoassemblies
The mechanism and kinetics of NiO reduction by hydrogen
Thermochemical approach
later, have remained a puzzle and a subject for discussion. The traditional theoretical approach, based on the kinetic Arrhenius equation and the mechanism of direct reduction of solid oxide to solid metal, have failed to provide a reliable quantitative
Abstract
What is learned in perceptual learning? How does perceptual learning change the perceptual system? We investigate these questions using a systems analysis of the perceptual system during the course of perceptual learning using psychophysical methods and models of the observer. Effects of perceptual learning on an observer's performance are characterized by external noise tests within the framework of noisy observer models. We find evidence that two independent mechanisms, external noise exclusion and stimulus enhancement support perceptual learning across a range of tasks. We suggest that both mechanisms may reflect re-weighting of stable early sensory representations.
-2 receptor alpha-chains (CD25). Breakdown of a single mechanism of self-tolerance causes various autoimmune diseases. J. Immunol., 1995, 155 , 1151–164. Asano M. Immunologic
Vanderah, T. W., Ossipov, M. H., Lai, J., Malan, T. P. Jr., Porreca, F. (2001) Mechanisms of opioid-induced pain and antinociceptive tolerance: descending facilitation and spinal dynorphin. Pain 92 , 5-9. Mechanisms of opioid
