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Molecular models in chemistry education at university and upper secondary school - structure of amides

Kolář Karel, Doležal Rafael, Karásková Natálie, Maltsevskaya Nadezhda V., Křížková Šárka

Chemistry-Didactics-Ecology-Metrology

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2019

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R. 24, NR 1-2

45--51

EN

Molecular models derived from results of quantum-chemical calculations present an important category of didactic instruments in chemistry education in upper secondary school and, particularly, at university. These models can be used especially as tools for supporting the students’ understanding by visual learning, which can adequately address complexity of many chemical topics, incorporate appropriate didactic principles, as well as utilize the benefits brought up by the actual information technology. The proposed molecular models are non-trivial examples of didactic application of computational chemistry techniques in illustration of electron interactions in amidic group, namely the interaction of the free electron pair on the nitrogen atom with the carbonyl group and also the interaction of atoms in the amide group with other surrounding atoms in the molecule. By these molecular models it is possible to explain acid-base properties of amides applying knowledge of electron density distribution in the molecules and the resulting electrostatic potential. Presentation of the structure and properties of the amides within education is important also for the reason that amidic functions are involved in many important natural substances (e.g. proteins, peptides, nucleic acids or alkaloids), synthetic macromolecular substances (e.g. Silon) or pharmaceutical preparations (e.g. paracetamol). Molecular models then serve to support better understanding of the structure of these substances and, in relation to it, their properties.

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Zastosowanie modeli cząsteczek w kształceniu nauczycieli chemii

Kolář K., Myška K., Holý I.

Prace Naukowe. Chemia i Ochrona Środowiska / Wyższa Szkoła Pedagogiczna w Częstochowie

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2003

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Vol. 7

111--116

PL

Przedstawiono nową metodę kształcenia studentów dotyczącą struktury elektronowej i jej znaczenia dla zjawisk chemicznych. Metoda ta opiera się na czterowymiarowych modelach rozkładu gęstości elektronowej generowanych komputerem. Modele te łatwo mogą być wykorzystane do rozszerzenia takich tematów jak delokalizacja elektronów, mechanizm reakcji, konformacja.

EN

A new method for education of chemistry teachers, concerning electronic stnicture and its importance for chemical phenomena is presented. The method relies on computer generated four dimensional models of electron density distributions. These models are easily applied to a broad range of topics such as delocalisation of electrons, reaction mechanisms and conformation.

3

Modelling of cell aging - system theoretic approach

Świerniak A., Kimmel M., Śmieja J., Rzeszowska-Wolny J.

Journal of Medical Informatics & Technologies

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2001

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Vol. 2, Part. 1

MI3--MI8

EN

We characterize the asymptotic behavior of telomeres shortening of which is supposed to be the mechanism of aging and death. The problem is described by models in the form of infinitely many differential linear first order equations, resulting from branching random walk processes used to represent the evolution of particles in this problem, under different assumptions dealing with stochastic characterization of the process. We use control theoretical machinery based on Laplace transforms, Tauberian theorems and transfer loop reduction.

4

Budowa topologiczna a elastyczność usieciowanych elastomerów

Galina H.

Polimery

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1999

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T. 44, nr 7-8

496-504

PL

Omówiono podstawowe pojęcia współczesnej teorii elastyczność elastomerów, podkreślając entropowy charakter tej właściwości. W sposób skrócony przedstawiono potencjalny wpływ splątań łańcuchów na moduł sprężystości i scharakteryzowano modele idealnych sieci gaussowskich: model afiniczny, fantomowy i z ograniczoną fluktuuacją węzłów. Bardziej szczegółowo omówiono zależności naprężę' nią od odkształcenia w przypadku odkształcenia jednoosiowej, uwzględniając przy tym parametr pamięci sieci polimerowej. Zaprezentowano także równanie Mooneya-Rivlina i jego pośredni związek z molekularnymi parametrami sieci polimeru.

EN

The basic terms of modern theories of rubber elasticity are reviewed with a brief reference to the effect of chain entanglements on the elasticity modulus of crosslinked polymers and a more detailed reference to stress-strain relationship for the case of uniaxial extension with due account of the memory of the polymer network. The Gaussian models including the affine, phantom and constrained junction models of ideal polymer networks are described. The Mooney-Rivlin equation is presented and its indirect link to molecular parameters of polymer networks is indicated.