S Matrix
Mostrando 1-12 de 1780 artigos, teses e dissertações.
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1. Sparse Estimation of the Precision Matrix and Plug-In Principle in Linear Discriminant Analysis for Hyperspectral Image Classification
ABSTRACT In this paper, a new method for supervised classification of hyperspectral images is proposed for the case in which the size of the training sample is small. It consists of replacing in the Mahalanobis distance the maximum likelihood estimator of the precision matrix by a sparse estimator. The method is compared with two other existing versions of L
Trends in Computational and Applied Mathematics. Publicado em: 2022
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2. Atomic Absorption Spectrometry as an Alternative to Determine the Presence of Gold Nanoparticles on or in Silica Matrix
Two different gold-silica-based nanomaterials were prepared: (i) silica-supported gold nanoparticles (AuNP/SiO2); and (ii) gold-silica core-shell nanoparticles (AuNP@SiO2). Three strategies for sample treatment (S), consisting in acid treatments, were employed: (S1) HNO3; (S2) HNO3 + HCl; and (S3) HF + HNO3 + HCl, applying microwave oven digestion for S2 and
Journal of the Brazilian Chemical Society. Publicado em: 2022
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3. BIODEGRADABLE SODIUM CARBOXYMETHYL CELLULOSE MEMBRANES CONTAINING MELALEUCA ESSENTIAL OILS FOR WOUND CARE MATERIAL
NaCMC is a biocompatible polymer that can be crosslinked with citric acid to form a gel matrix. Melaleuca oils have antimicrobial and anti-inflammatory properties with potential for wound healing. The goal of this work was to investigate the characteristics of NaCMC-Melaleuca oils gels. The gels were characterized by FTIR, TGA, mechanical analysis, and in vi
Química Nova. Publicado em: 2022
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4. Assessment of Covariance Selection Methods in High-Dimensional Gaussian Graphical Models
ABSTRACT The covariance selection in Gaussian graphical models consists in selecting, based on a sample of a multivariate normal vector, all those pairs of variables that are conditionally dependent given the remaining variables. This problem is equivalent to estimate the graph identifying the nonzero elements on the off-diagonal entries of the precision mat
Trends in Computational and Applied Mathematics. Publicado em: 2022
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5. Phase Adjustment of S-Parameters from Coupled Resonator Filters
Abstract This paper presents a method to cancel the constant phase loading and transmission line that are added to the S-parameters of coupled resonant networks. Thus, the phase-corrected S-parameters may be used to obtain a rational model together with its representative coupling matrix. This method is applicable to lossy and lossless coupled resonator netw
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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6. Cascade Modeling of the Measuring System Used to Assess S-Parameters of Anchor Rods on Power Transmission Lines Guyed Towers
Abstract The structural condition of the cable-stayed towers anchorage on power transmission lines requires constant monitoring. Maintenance routines must be able to identify faulty anchor rods and substitute them to avoid tower collapses and power delivery interruptions. Modern statistical diagnostic systems based on machine learning requires the generation
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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7. Obtainment of a new metal matrix composite from the recycling of UNS S31803 duplex stainless steel by powder metallurgy
Abstract The purpose of circular economy is to maximize resources efficiency. With the increase in consumption of raw materials, energy and waste generation, recycling is necessary for environmental and industrial reasons. Thus, the powder metallurgy, together with mechanical milling, stands as a new method for scraps recycling. This study aimed to produce U
REM - International Engineering Journal. Publicado em: 2022
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8. Determinação de etil-glicuronídeo e etil-sulfato em sangue por UPLC-MS/MS: aplicação clínica em vítimas de trauma
We developed a UPLC-MS/MS method for the quantification of the ethanol metabolites ethyl-glucuronide (EtG) and ethyl-sulfate (EtS) in blood samples. Sample preparation was a protein precipitation with acetonitrile 0.1% formic acid containing internal standards (IS) 0.5 µg mL-1 EtG-D5 and EtS-D5. Chromatographic separation was performed in a fluoro-phenyl co
Química Nova. Publicado em: 2022
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9. Development and Validation of a Rapid and Reliable HPLC-FLD Method for the Quantification of Ciprofloxacin and Enrofloxacin Residues in Zea mays
The accumulation of antibiotics by plants is a currently concern associated to yield reduction and transference of antibiotic residues along the food web. Maize is a staple food in many parts of the world; it is also considered an important ingredient in animal nutrition. Considering the lack of validated analytical methods for the analysis of ciprofloxacin
Journal of the Brazilian Chemical Society. Publicado em: 2022
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10. Detection of Microorganisms in Clinical Sonicated Orthopedic Devices Using Conventional Culture and qPCR
Resumo Objetivo Avaliar a sensibilidade e a especificidade da reação em cadeia de polimerase em tempo real quantitativa (quantitative real-time polymerase chain reaction, qPCR, em inglês) para a triagem do gene rDNA 16S, com a utilização do fluido sonicado de implantes ortopédicos. Métodos Um estudo retrospectivo foi realizado em 73 fluidos sonicado
Revista Brasileira de Ortopedia. Publicado em: 2022
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11. DESIGN AND EXPERIMENT OF A SAFFLOWER PICKING ROBOT BASED ON A PARALLEL MANIPULATOR
ABSTRACT To mitigate the large demand for safflower picking labour and the low efficiency of manual picking, a safflower picking robot that is based on a parallel manipulator is designed. The whole robot mainly consists of a walking device, parallel manipulator device, vision device, picking device, filament collection device, control system, and motor drive
Engenharia Agrícola. Publicado em: 2022
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12. Simultaneous GC-NCI-MS Determination of Persistent Organic Pollutants and Current-Use Pesticides in Breast Milk Samples
To preserve human health, persistent organic pollutants (POPs) and current-use pesticides (CUPs) should be monitored in fatty tissues, including breast milk. Therefore, this study aimed to optimize sample preparation conditions using a 32 factorial design for the determination of POPs and CUPs by gas chromatography coupled to mass spectrometry with negative
Journal of the Brazilian Chemical Society. Publicado em: 2022