Nonlinear Spectroscopy
Mostrando 1-12 de 61 artigos, teses e dissertações.
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1. Compatibility by a Nonisothermal Kinetic Study of Azathioprine Associated with Usual Excipients in the Product Quality Review Process
Azathioprine is an immunosuppressive drug for several inflammatory disorders. Due to its clinical relevance, to explore the solid-state properties for excipient compatibility in the product quality review process is essential. Fourier transform infrared spectroscopy, powder X-ray diffraction and thermal analysis (thermogravimetry/derivative thermogravimetry
J. Braz. Chem. Soc.. Publicado em: 2021-03
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2. Vibrational Spectroscopy and Chemometrics in Forensic Chemistry: Critical Review, Current Trends and Challenges
The present manuscript makes an extensive review of the scientific approaches developed in the last decade involving infrared and Raman spectroscopy combined with chemometrics for solving several issues in the investigation of the most relevant forensic traces, such as questioned documents and currency, explosives, gunshot residues, illicit drugs and body fl
J. Braz. Chem. Soc.. Publicado em: 24/10/2019
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3. A Regional Legacy Soil Dataset for Prediction of Sand and Clay Content with Vis-Nir-Swir, in Southern Brazil
ABSTRACT The success of soil prediction by VIS-NIR-SWIR spectroscopy has led to considerable investment in large soil spectral libraries. The aims of this study were 1) to develop a soil VIS-NIR-SWIR spectroscopy approach using legacy soil samples to improve spectral soil information in a regional scale; (2) to compare six spectral preprocessing techniques;
Rev. Bras. Ciênc. Solo. Publicado em: 15/08/2019
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4. Preliminary investigation of Terahertz spectroscopy to predict pork freshness non-destructively
Abstract Freshness, a very important criterion for pork quality control, is normally assessed by the index of K value. In this paper, Terahertz (THz) spectroscopy was employed to predict K value of pork nondestructively. The THz spectra (0.2~2.0THz) of 80 pork samples with different freshness in the attenuated total reflectance (ATR) mode were acquired. Simu
Food Sci. Technol. Publicado em: 22/07/2019
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5. Minimization of polymerization shrinkage effects on composite resins by the control of irradiance during the photoactivation process
Abstract High levels of shrinkage stress caused by volumetric variations during the activation process are one of the main problems in the practical application of composite resins. Objective The aim of this study is to reduce the shrinkage stress and minimize the effects caused by composite resin volumetric variation due to the photopolymerization. In thi
J. Appl. Oral Sci.. Publicado em: 18/06/2018
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6. Thermogravimetric and spectroscopic study (TG–DTA/FT–IR) of activated carbon from the renewable biomass source babassu
Activated carbons (ACs) with well–developed microstructure and high microporosity were obtained from biomass by potassium hydroxide activation. The preparation process consisted in producing carbon materials in the ratios of activating agent to raw material 70:30, 50:50, 30:70 and 25:75 (w/w) characterized by thermal analysis coupled to spectroscopy (TG–
Quím. Nova. Publicado em: 2017-04
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7. Synthesis, Characterization and Electromagnetic Properties of SnO-coated FeNi Alloy Nanocapsules
SnO-coated FeNi alloy nanocapsules have been synthesized by an arc-discharge method. High-resolution transmission electron microscopy and x-ray photoelectron spectroscopy analysis show that the nanocapsules have a shell/core structure with FeNi alloy nanoparticles as the core and amorphous SnO as the shell. Dielectric relaxation of SnO shell and the interfac
Mat. Res.. Publicado em: 10/10/2016
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8. Grain-Boundary Resistance and Nonlinear Coefficient Correlation for SnO2-Based Varistors
This work has focused on the electrical and microstructural properties of Nb2O5-doped SnO2-MnO2 ceramics. The pellets were prepared by solid-state reaction method according to the system (99.5-x) SnO2 - 0.5 MnO2 - x Nb2O5, on the following molar ratio x = 0.05; 0.10; 0.15; 0.20 and 0.25. Scanning electron microscopy and electrical measurements (ac and dc) we
Mat. Res.. Publicado em: 26/09/2016
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9. Dynamically Configurable Nonlinear Optical Switching Based on Vertically Aligned Carbon Nanotubes
Abstract The modification of the third order nonlinear optical response exhibited by vertically aligned carbon nanotubes in two-wave mixing interactions was analyzed. All-optical switching effects were explored by using a vectorial optical Kerr gate with nanosecond pulses at 532 nm wavelength of excitation. The samples were prepared by a spray pyrolysis meth
Mat. Res.. Publicado em: 01/08/2016
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10. Studies on Growth, Spectral, Thermal, Mechanical and Optical Properties of 4-Bromoanilinium 4-Methylbenzenesulfonate Crystal: A Third Order Nonlinear Optical Material
Abstract 4-Bromoanilinium 4-methylbenzenesulfonate (4BPTS) single crystal was successfully grown from ethanol by slow evaporation method at room temperature. The structure of grown crystal was confirmed by single crystal X-ray diffraction studies. The presence of functional groups of grown crystal was confirmed by the Fourier transform infrared spectroscopy
Mat. Res.. Publicado em: 18/07/2016
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11. PF/CLAY hybrid materials: a simple method to modulate the optical properties
Abstract The aim of this work was modulate the emission properties and improve thermal stability of a conjugated polymer incorporated into an inorganic matrix. Hybrid material was prepared based on poly(9,9-dioctylfluorene-co-phenylene (PF) and montmorillonite (Na+Mt) clay using wet impregnation of 10, 30 and 50 wt.% of PF into Na+Mt and Na+Mt intercalated w
Polímeros. Publicado em: 15/03/2016
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12. Ultrafast Dynamics of Au Nanopyramid Interfaces Prepared by Nanosphere Lithography: Effect of Substrate Chemical Composition
This work describes ultrafast spectroscopy studies of Au triangular pyramid particle arrays deposited over glass (termed Au/glass), and 190 nm indium tin oxide (ITO) film (termed Au/ITO/glass) prepared by nanosphere lithography. The linear absorption spectra of Au/glass and Au/ITO/glass exhibit surface plasmon resonances at 800 and 870 nm, respectively, in g
J. Braz. Chem. Soc.. Publicado em: 2016-02