Spectral Density
Mostrando 1-12 de 146 artigos, teses e dissertações.
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1. New Pair of 2-Amino-naphthoxazoles Derived from β-Lapachone: Synthesis, Spectral Evaluation and Crystal Structure
This work describes a novel synthetic route for obtaining 2-amino-naphthoxazoles derived from β-lapachone, which consists of a condensation reaction between β-lapachone and thiourea in a basic medium. This synthetic approach can be seen as a potential route for obtaining 2-amino-oxazoles from quinones. The obtained amino-naphthoxazoles were characterized b
J. Braz. Chem. Soc.. Publicado em: 2021-05
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2. Understanding Solvent/Bixin Interactions by Raman Spectroscopy
In this work, Raman spectroscopy and density functional theory (DFT) calculations have been used in order to understand the nature of the interaction between the carotenoid bixin and organic solvents with dielectric constant varying from ca. 2 (toluene) to ca. 47 (dimethyl sulfoxide). Raman shifts registered for the main carotenoid marker band, the C=C stret
J. Braz. Chem. Soc.. Publicado em: 2020-07
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3. DEVELOPING NEAR INFRARED SPECTROSCOPIC MODELS FOR PREDICTING DENSITY OF Eucalyptus WOOD BASED ON INDIRECT MEASUREMENT
ABSTRACT The objective of this study was to establish multivariate models for the prediction of wood basic density with reference to the values of average density of trees and near infrared (NIR) spectra measured in the breast height. The wood basic density of 39 Eucalyptus clones was determined in the laboratory by means of the mean longitudinal positions o
CERNE. Publicado em: 20/12/2019
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4. Introduction of Application of Gini Coefficient to Heart Rate Variability Spectrum for Mental Stress Evaluation
Resumo Fundamento: O coeficiente de Gini é um instrumento estatístico geralmente usado por economistas para quantificar a desigualdade de renda. No entanto, ele pode ser aplicado a qualquer tipo de dados com distribuição desigual, incluindo a variabilidade da frequência cardíaca (VFC). Objetivos: Avaliar a aplicação do coeficiente de Gini para medi
Arq. Bras. Cardiol.. Publicado em: 09/09/2019
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5. Ligand and Solvent Effects on the Structural and Optical Properties of Au13L83+ Clusters: a Density Functional Theory Study
Density functional theory (DFT) calculations have been performed to develop a systematic structural analysis of Au13L83+, where L = SCH3, SeCH3, SCH2OCH3 and S(CH2)2NH2, in order to examine the influence of different ligands. Binding energy calculations indicate that the gold core is more stabilized by the ligand in the following sequence S(CH2)2NH2 > SCH2OC
J. Braz. Chem. Soc.. Publicado em: 04/07/2019
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6. A MEASUREMENT SYSTEM BASED ON LiDAR TECHNOLOGY TO CHARACTERIZE THE CANOPY OF SUGARCANE PLANTS
ABSTRACT Laser sensor applications associated with LiDAR (Light Detection and Ranging) technology on platforms allow the evaluation of crop and forest biomass in a non-invasive way. This study presents the development of a measurement system based on LiDAR technology aimed at the proposed assessment of the height of sugarcane plants during the pre-harvest pe
Eng. Agríc.. Publicado em: 25/04/2019
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7. 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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8. Silicon Nanostructuring Using SF6/O2 Downstram Plasma Etching: Morphological, Optical and Sensing Properties
Silicon (Si) nanostructures were prepared in the downstream of radiofrequency SF6/O2 mixture plasma generated in 13.56 MHz hollow cathode discharge system. Depending on the oxygen percentage in the mixture, the obtained Si nanostructures were characterized for their different properties: etching rate, morphology, optical reflectance, photoluminescence, spect
Mat. Res.. Publicado em: 10/07/2018
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9. Optimization of structures subjected to dynamic load: deterministic and probabilistic methods
Abstract This paper deals with the deterministic and probabilistic optimization of structures against bending when submitted to dynamic loads. The deterministic optimization problem considers the plate submitted to a time varying load while the probabilistic one takes into account a random loading defined by a power spectral density function. The correlation
REM, Int. Eng. J.. Publicado em: 2016-09
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10. Comparison of In-Flight Measured and Computed Aeroelastic Damping: Modal Identification Procedures and Modeling Approaches
ABSTRACT The Operational Modal Analysis technique is a methodology very often applied for the identification of dynamic systems when the input signal is unknown. The applied methodology is based on a technique to estimate the Frequency Response Functions and extract the modal parameters using only the structural dynamic response data, without assuming the kn
J. Aerosp. Technol. Manag.. Publicado em: 2016-06
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11. Orientation of Pterin-6-Carboxylic Acid on Gold Capped Silicon Nanopillars Platforms: Surface Enhanced Raman Spectroscopy and Density Functional Theory Studies
The orientation of pterin-6-carboxylic acid on gold nanopillars was investigated by surface enhanced Raman spectroscopy and density functional theory methods. The experimentally vibrations from pterin-6-COOH free and attached to the Au surface display vibration features indicating chemical interaction of the pterin with the metal surface. The spectral featur
J. Braz. Chem. Soc.. Publicado em: 2016-05
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12. Sampling Position under No-Tillage System Affects the Results of Soil Physical Properties
ABSTRACT Understanding the spatial behavior of soil physical properties under no-tillage system (NT) is required for the adoption and maintenance of a sustainable soil management system. The aims of this study were to quantify soil bulk density (BD), porosity in the soil macropore domain (PORp) and in the soil matrix domain (PORm), air capacity in the soil m
Rev. Bras. Ciênc. Solo. Publicado em: 29/04/2016