Sol Gels
Mostrando 1-12 de 23 artigos, teses e dissertações.
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1. Effect of hydroxyurea (HU) on gelatinization mechanism of type I collagen suspensions
ABSTRACT Mutant hemoglobins thermodynamic phase transitions (HbS, HbC, etc.) have been the causes of serious hemoglobinopathies that have been affecting mankind since the dawn of human race. HbS polymerization is the best known of these transitions and the original cause of sickle cell anemia. Hydroxyurea (HU, NH2CONHOH) is widely used as the main drug admin
Matéria (Rio J.). Publicado em: 06/12/2018
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2. NIR Luminescence from Sol-Gel Er3+ Doped SiO2:GeO2 Transparent Gels, Nanostructured Powders and Thin Films for Photonic Applications
Samples of (1 – x)SiO2:xGeO2 compositions, containing x = 10 and 20, and doped with Er3+, were prepared by a simple sol-gel route. Homogeneous and transparent gels were synthesized and xerogels were obtained by gel annealing from 700 ºC to 1100 ºC. Films exhibiting high transmittance in the visible and near infrared were deposited by spin-coating techniq
J. Braz. Chem. Soc.. Publicado em: 2015-12
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3. INFLUÊNCIA DO CATALISADOR EM SOLUÇÕES POLIMÉRICAS PARA O PREPARO DE GÉIS ORGÂNICOS DE RESORCINOL-FORMALDEÍDO
Resorcinol-formaldehyde (RF) organic gels have been extensively used to produce carbon aerogels. The organic gel synthesis parameters greatly affect the structure of the resulting aerogel. In this study, the influence of the catalyst quantity on the polymeric solution sol-gel process was investigated. Sodium carbonate was used as a basic catalyst. RF gels we
Quím. Nova. Publicado em: 2015-11
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4. Cyclic oxidation resistance of rare earth oxide gel coated Fe-20Cr alloys
Rare earths (RE) have been used to increase high temperature oxidation resistance of chromium dioxide and alumina forming alloys. The RE can be added as elements (or oxides) to the alloys or applied as an oxide coating to the alloy surface. RE oxide gels, obtained by the sol-gel technique, were used to coat Fe-20Cr specimens prior to cyclic oxidation tests i
Materials Research. Publicado em: 2007-09
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5. Effect of surface deposited rare earth oxide gel characteristics on cyclic oxidation behavior of Fe20-Cr alloys
Rare earths have been used to increase high temperature oxidation resistance of many chromium dioxide and alumina forming alloys. These rare earths can be added as elements (or as oxide dispersions) to the alloys or applied as an oxide coating to the alloy surface. The sol-gel technique is considered to be very efficient to apply fine oxide particle coatings
Materials Research. Publicado em: 2006-06
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6. Transição sol-gel em soluções orgânico-aquosas de lisozima e o efeito indutor do solvente: caracterização cinética e estrutural / Sol-gel transition in aqueous-organic solutions of lysozyme and the solvent-inducing effect: a kinetic and structural characterization
Lysozyme sol-gel transition in tetramethylurea/water was investigated in depth. These dispersions produced highly viscous systems, which evolved to physical gels, i.e., systems where the gel backbone is maintained by van der Walls forces and hydrogen bonding. The work was conducted in two fronts: a) the study of lysozyme dispersions in binary mixtures; b) th
Publicado em: 2006
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7. Oxido misto de SiO2/SnO2,SiO2/SnO2/Fosfato : propriedades e aplicações / The SiO2/SnO2, SiO2/SnO2/fosfato mixed oxide : properties and applications
The present work describes the preparation of SiO2/SnO2 mixed oxide obtained by the sol-gel processing method with Sn compositions (in wt %) of 4, 13 and 18%. The high specific surface and the presence of Lewis and Brfnsted acid sites, constitutes an interesting substrate for preparing new classes of chemically modified electrodes. In a specific application,
Publicado em: 2005
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8. GÃis de goma do cajueiro e derivados com quitosana - sÃntese, caracterizaÃÃo e ensaios preliminares em sistemas de liberaÃÃo de fÃrmacos. / Gels of cashew gum (cg) and derivatives with chitosan (ch): syntesis; characterization and assays preliminary in systems of release of farmacos.
GÃis de goma do cajueiro e/ou derivados com quitosana foram sintetizados por trÃs diferentes rotas: complexaÃÃo polieletrolÃtica, re-acetilaÃÃo de quitosana e pelo mecanismo de formaÃÃo de base de Schiff. GÃis de goma do cajueiro carboximetilada com quitosana obtido por complexaÃÃo polieletrolÃtica (CPE) foram caracterizados por titulaÃÃo cond
Publicado em: 2005
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9. Rare earth oxide coatings to decrease high temperature degradation of chromia forming alloys
The addition of small quantities of reactive elements such as rare earths (RE) to chromia or alumina forming alloys improves the high temperature oxidation resistance. Traditionally, these elements are alloying additions or are added as oxides to form a dispersion. The alloys can also be coated with RE oxides. Several methods can be used to coat alloy substr
Materials Research. Publicado em: 2004-03
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10. Alumina synthesis by sol-gel method: characterization and application on epoxidations reactions / "Sintese de aluminas utilizando-se o metodo sol-gel : caracterização e aplicação em reações de epoxidação"
A alumina tem sido muito utilizada como catalisador ou suporte de catalisador em diversas áreas da química. Neste trabalho sintetizou-se aluminas pelo método sol-gel através da hidrólise de alcóxidos de alumínio e subseqüentes condensações em soluções ácidas. Foi utilizado como fonte de alumínio o tri(iso-propóxido) de alumínio e o tri(sec-bu
Publicado em: 2004
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11. Preparo e caracterização de microcapsulas obtidas por polimerização ionica para alimentação de larvas de peixe / Preparation and characterization of microcapsules obtained by polymerization Ionica feeding of fish larvae
This research aimed at producing microcapsules capable of retaining proteins, with the objective of substituting the live organisms used in larval fish feed. Four different polysaccharides: alginate, carrageenan, gelan gum and pectin were used, all having the capacity to form gels by ionic polymerization both individually and in association, in order to prod
Publicado em: 2003
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12. Evaluation of the Influence of Microwaves in the Structure of Silica Gels
In this work we studied the influence of microwaves in the pore structure of silica gels obtained via sol-gel polymerization process. We analised the feasibility of replacing conventional heating by microwave heating during drying. Structural parameters such as specific volume of pores (Vp), specific surface area (Sp), average pore size (r p) and the bulk an
Materials Research. Publicado em: 2002-10