Search results for " stability."
showing 5 items of 1315 documents
A library of monoalkenylsilsesquioxanes as potential comonomers for synthesis of hybrid materials
2018
In this paper we demonstrate a facile and efficient synthesis of monoalkenylsubstituted POSS compounds, i.e., R7(Si8O12)-alkenyl and R7(Si8O12)(OSiMe2)-alkenyl with a functional alkenyl group of chain length (from vinyl to dec-9-enyl, with or without additional –OSiMe2– spacer between the silsesquioxane core and alkenyl moiety) and with five types of inert groups (Et, iBu, iOc, Cy, Ph) at the POSS core. These compounds constitute a library of monosubstituted POSS systems, including thorough spectroscopic and thermal characteristics. These findings could be especially useful for material chemists applying the compounds as modifiers or comonomers for copolymerization reaction, e.g., with olef…
Thermal and thermo-oxidative stability and kinetics of decomposition of PHBV/sisal composites
2017
The decomposition behaviours of composites made of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and sisal were assessed in terms of thermal stability and decomposition kinetics, under inert and oxidative conditions, by means of multi-rate linear non-isothermal thermogravimetric experiments. A statistical design of experiments was applied to study the influence of the addition of sisal (0-10-20-30%wt), the presence coupling agent (Yes/No) and the applied conditions of work (inert or oxidative). An improvement of the thermal and thermo-oxidative stability of PHBV with the addition of sisal was observed for all cases. An accurate methodology based on iso-conversional methods was applied…
Latvijas rūpniecībai aktuālu farmaceitiski aktīvo vielu kristālsolvāti
2013
ANOTĀCIJA Promocijas darbs veltīts Latvijas tautsaimniecībai aktuālu farmaceitiski aktīvo vielu (FAV) izpētei. Veikti apskatīto vielu kristālsolvātu meklējumi un iegūtas līdz šim neaprakstītas vielu kristāliskās formas. Novērtēta iegūto formu stabilitāte iegūšanas, ražošanas un uzglabāšanas apstākļos. Atsevišķām FAV veikta struktūras noteikšana, gan izmantojot pulvera rentgendifraktometriju, gan monokristālu rentgendifraktometriju. Iegūtie rezultāti ir aktuāli zāļu ražotājiem, kā arī tiem ir zinātniska nozīme no FAV īpašību apzināšanas un metožu attīstības viedokļa. Atslēgas vārdi: kristālsolvāti, vielas stāvokļa diagramma, nestehiometriskie solvāti, vielu termodinamiskā stabilitāte, fāžu p…
Experimental evolution of genome architecture and complexity in an RNA virus
2016
Introducción La evolución de la arquitectura del genoma – las dimensiones y la organización del material hereditario de un organismo – es poco conocida. Existe una variación asombrosa en la arquitectura genómica entre diferentes organismos. Los virus tienden a tener genomas pequeños, con un mínimo de secuencias intergénicas y típicamente con genes solapantes, los cuales se cree son una forma de compresión del genoma que permite al virus incrementar su número de proteínas sin aumentar su tamaño. Los procariotas tienen genomas compactos, pero con secuencias intergénicas más largas que los virus, y los genes con solapamientos largos son escasos. Los eucariotas presentan una amplia gama de tama…
Cadmium Metal–Organic Frameworks Based on Ditopic Triazamacrocyclic Linkers: Unusual Structural Features and Selective CO 2 Capture
2017
International audience; Two three-dimensional cadmium metal organic frameworks with general formula [Cd-2(L-1)(H2O)(3)](NO3)(0.7)(HCOO)(0.2)Br-0.1 (Cd2L1, L-1 = 1,4,7-tris(4-carboxybenzy1)-1,4,7-triazacyclononane) and Cd(HL2)(H2O)(2) (CdL2, L-2 = 1,4,7-tris(3-(4-benzoate)prop-2-yn-1-yl)-1,4,7-triazacydononane) based on 1,4,7-triazacyclononane N-functionalized by different arylcarboxylic acids were prepared under solvothermal conditions and characterized by single crystal X-ray analysis and porosity measurements. The crystal structure of Cd2L1 reveals a cationic net with a bcs topology,. and nodes are constituted by dinuclear cadmium complexes, in which each cadmium atom adopts a hexacoordin…