Chemical Bond
Mostrando 13-24 de 364 artigos, teses e dissertações.
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13. Mechanical properties of mortar produced with the replacement of natural sand by scheelite residue
Resumo O resíduo gerado pelas atividades industriais representa um custo, já que os geradores são responsáveis pela sua gestão, transporte, tratamento e disposição. O estado do Rio Grande do Norte, Brasil, é o maior produtor de resíduos de scheelita. O objetivo desta pesquisa foi caracterizar este resíduo de mineração, identificar sua similaridad
Cerâmica. Publicado em: 15/08/2019
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14. Facial Selectivity between Carbohydrates and Aromatic Amino Acids Explained by a Combination of NCI, NBO and EDA Techniques with NMR Spectroscopy
The influence of electrostatic and dispersion components of intermolecular interactions on the recognition of carbohydrates by aromatic protein residues is important for many biological processes. Interactions between glucose and galactose and aromatic moieties of tryptophan, phenylalanine and histidine were investigated through 1H nuclear magnetic resonance
J. Braz. Chem. Soc.. Publicado em: 08/04/2019
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15. APCI(+)FT-ICR MS Analysis of Hydrocarbons Using Isooctane as Ionizing Reagent - A Comparison with HTGC-FID, GC×GC-MS and NMR
Hydrocarbons present in saturated fractions of crude oils can be assessed by atmospheric pressure chemical ionization (APCI) using small hydrocarbons as ionizing reagents in a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS). In this work, five paraffin standards of different average molar mass distributions (Mw) were easily ionized by
J. Braz. Chem. Soc.. Publicado em: 08/04/2019
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16. Effect of Self-Etching Primer Associated to Hydrofluoric acid or Silane on Bonding to Lithium Disilicate
Resumo Avaliar o efeito da combinação de ácido fluorídrico ou silano com o primer autocondicionante de cerâmicas sobre a eficácia da união imediata e após 1 ano de armazenamento em água, padrão de condicionamento e interação química desses tratamentos com o dissilicato de lítio. Um total de 16 blocos CAD/CAM de dissilicato de lítio (DL) foram
Braz. Dent. J.. Publicado em: 04/04/2019
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17. SYNTHESIS, ELECTRONIC AND SPECTRAL PROPERTIES OF NEW 1,3,4-THIADIAZOLE COMPOUNDS AND THE SPECTRAL ANALYSIS OF THEIR CONFORMERS USING DENSITY FUNCTIONAL THEORY
In this study, new 1,3,4-thiadiazole compounds were synthesised and characterised by FT-IR, 1H-NMR, UV-vis spectroscopy and elemental analysis, Furthermore, the relationship between the electronic and spectral data of the 16 conformers of each compound was investigated by theoretical calculations; the theoretical data were compared with the experimental resu
Quím. Nova. Publicado em: 2019-02
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18. MOLECULE DESIGN AND PROPERTIES OF CYCLIC ENERGETIC MATERIALS BASED ON NITROGUANIDINE AND 1,1-DIAMINO-2,2-DINITROETHENE
A series of cyclic energetic derivatives based on nitroguanidine and 1,1-diamino-2,2-dinitroethene were theoretically designed. The spatial structures, infrared spectrometry, heats of formation, electronic structures, detonation properties, and thermal stabilities of these designed compounds were fully investigated by density functional theory. It is found t
Quím. Nova. Publicado em: 2019-02
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19. Investigation on Structural, Morphological and Relaxometric Properties of Lamellar Zrp Modified with Long Chain Amine
In order to search nanofiller for controlling release of drugs lamellar α-zirconium phosphate (α-ZrP) was modified with ether-amine oligomer (E-A). Synthesis and chemical modification followed specific reaction conditions and different EA:ZrP ratios. Infrared spectra showed strong interaction between P-OH and NH2 groups. Thermogravimetric curves showed tha
Mat. Res.. Publicado em: 17/01/2019
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20. Characterization of hibiscus sabdariffa fiber as potential reinforcement for denture acrylic resins
ABSTRACT This study aimed to determine the characteristics of Hibiscus sabdariffa as a fiber-reinforcement material for denture acrylic resins. The Hibiscus sabdariffa fiber was extracted by hot water retting. The fiber was treated at room temperature in aqueous solution of NaOH for 8 hours at 8% concentration. Micrometre gauge and Field emission scanning el
Matéria (Rio J.). Publicado em: 06/12/2018
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21. Adsorción de aniones en electrodos. nanoestructurados de Ag sobre HOPG
ABSTRACT The structure and properties of the electrochemical interface result from the interactions that occur between the different components of an electrolytic solution and the metal electrode. In particular, the anion / metal interactions have been of great interest in recent years, mainly due to the development of new techniques that have allowed the st
Matéria (Rio J.). Publicado em: 19/07/2018
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22. Adsorción y oxidación de monóxido de carbono en una lamina de ß-grafino: Estudio teórico
ABSTRACT This work presents a study, based on the Density functional theory (DFT), of the adsorption and oxidation of CO on a free platinum catalyst constituted from a sheet of Graphyne. Graphyne is a new allotrope of carbon, its structure is two-dimensional and is constituted by a monolayer of carbon atoms with sp-sp2 hybridization. Depending on the differe
Matéria (Rio J.). Publicado em: 19/07/2018
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23. Study of the chemical interaction between a high-viscosity glass ionomer cement and dentin
Abstract Objective To investigate the chemical interactions between a high-viscosity glass ionomer cement (GIC) (KetacTM Molar Easymix, 3M ESPE, Seefeld, Bavaria, Germany) and human dentin. It was also analyzed the dynamics of GIC setting mechanism based on the time intervals required for the GIC and the GIC mixed with dentin to achieve stability. Materia
J. Appl. Oral Sci.. Publicado em: 16/07/2018
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24. Synthesis of Graphene Oxide and Functionalized CNT Nanocomposites Based on Epoxy Resin
ABSTRACT Lately, nanomaterials have been largely studied as reinforcements for epoxy resin. Although their usage is highly promising, the literature has reported some drawbacks regarding the improvement of mechanical properties in nanocomposites. These difficulties are usually due to dispersion of nanomaterials and its adhesion to the polymeric matrix. One a
J. Aerosp. Technol. Manag.. Publicado em: 16/07/2018