Absorption Cross Section
Mostrando 1-12 de 36 artigos, teses e dissertações.
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1. Evaluation of a Metal-Organic Composite (Tungsten-Lignin) for Attenuation of Gamma Radiation
The objective of this work was to use tungsten and lignin as precursors to obtain a metal-organic composite tungsten-lignin (W-Lig) using different sintering temperatures. Tungsten is a refractory metal and it was selected for the composite since it is widely used for high-energy radiation shielding as it has an excellent absorption cross section for thermal
Mat. Res.. Publicado em: 02/09/2019
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2. Heavy metal concentrations and ecological risk assessment of the suspended sediments of a multi-contaminated Brazilian watershed
ABSTRACT. Metal concentrations in suspended sediments of one of the most polluted rivers in Brazil were measured. Concentrations of Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn were determined by inductively coupled plasma while Hg and As were analyzed with hydride generation flow injection atomic absorption spectroscopy. Contamination of As, Cd, Cr, Cu, Fe, Hg, Mn, N
Acta Sci., Agron.. Publicado em: 28/03/2019
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3. A New Configuration of Circular Stepped Tubes Reinforced with External Stiffeners to Improve Energy Absorption Characteristics Under Axial Impact
Abstract State-of-the art studies of impact crushing circular stepped tube (inversion tube) introduce various approaches to improve the energy absorption capacities. Adding external longitudinal stiffeners on the circular stepped tubes is a new approach that have a great effect and interest. In the current study, finite element analysis using (LS-DYNA/WORKBE
Lat. Am. j. solids struct.. Publicado em: 2017-02
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4. Utilization of banana stalk fiber as reinforcement in low density polyethylene composite
ABSTRACT Natural fibers could serve as viable and abundant alternatives to the expensive and non - renewable synthetic fibers as reinforcement in thermoplastic composites. The potentiality of banana stalk fiber at reinforcing a low density polyethylene matrix was examined in this study. Fibers were extracted from the stalk of banana plant and characterized f
Matéria (Rio J.). Publicado em: 2016-12
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5. Investigação do efeito de grupos periféricos de rutênio sobre as propriedades fotofísicas de porfirinas
In the last few years the search for new organometallic complexes that exhibit large and fast optical responses at UV-Vis and near IR spectrum regions have attracted a considerable interest because of their potential application in devices such as sensors, optical limiters, switches and in medicine, being used as sensitive drugs in photodynamic treatments. A
Publicado em: 2011
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6. Estudos das propriedade óticas não lineares em meios dopados com absorvedores lentos
Neste trabalho, usando um laser de Ti3+:Safira sintonizado em 803nm como comprimento de onda de excitação, foram realizadas medidas de Z-scan resolvidas no tempo para caracterizar as propriedades óticas não lineares de matrizes vítreas à base de fosfato. Tal matriz denominada PAN (P2O5-Al2O3-Na2CO3) foi dopada com concentrações crescentes de Nd3+, va
Publicado em: 2011
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7. Propriedades Ãpticas dos vidros Er3+:PbPO4 / Optical Properties of the Er3+:PbPO4 Glasses
In this work we employ several techniques to investigate the optical properties of moderately high Er3+-doped lead phosphate (EDLP) glasses. The third-order optical susceptibility, χ3, and dispersion of the linear refractive index, n0(λ), of Er3+:PbPO4 were measured in the wavelength range between 400 and 1940 nm by using the spectrally resolved fe
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 02/07/2010
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8. Nonlinear optical properties of organic and organometallic compounds / Propriedades ópticas não lineares de compostos orgânicos e organometálicos
In the last few years, the design and characterization of novel materials exhibiting high optical nonlinearities is the subject of a fast-growing interest because of their potential application in various fields, from biology to photonics. Two-photon absorption processes, for example, have been used for optical limiting, three-dimensional microfabrication, o
Publicado em: 2009
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9. Seção de choque de absorção de buracos negros de Schwarzschild e de buracos acústicos canônicos / Section of shock of absorption of black holes of Schwarzschild and of canonical acoustic holes
In this dissertation we compute the absorption cross section of Schwarzschild black holes for the massless scalar and electromagnetic fields. We also compute the absorption cross section of canonical acoustic holes for sound waves. We use a numerical method to obtain the results in arbitrary frequencies. We also obtain analytic expressions for the low- and h
Publicado em: 2008
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10. Medida da secção de choque térmica e da integral de ressonância da reação 41K(n,)42K / Thermal cross-section and resonance integral of the 41K(n,g)42K(n,g)43K reaction measurement
Pellets of potassium nitrate were irradiated in the IPEN/CNEN-SP (Instituto de Pesquisas Energeticas e Nucleares, Comissao de Energia Nuclear, Sao Paulo, SP) IEAR1m reactor core operating at 2 MW power in order to determine the 41K(n,g)42K reaction thermal cross-section and resonance integral. The neutron flux was monitored by Au-Al alloy foils, and the West
Publicado em: 2008
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11. Development and application of the pulse train hyper-Rayleigh scattering technique. / Desenvolvimento e aplicação da técnica de hiper Rayleigh com trem de pulsos
This thesis reports an extension of the Hyper-Rayleigh scattering technique (HRS) and its application to study the mechanisms that contribute to the molecular first hyperpolarizabilities (). We use a Nd:YAG laser, Q-switched and mode-locked, as pumping beam to excite the samples. The laser delivers 100 ps pulses modulated by a Q-switch envelope, and the outp
Publicado em: 2008
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12. Influence of different formulations of bleaching agents on enamel and dentin physical and chemical properties / Influencia de diferentes formulações de agentes clareadores nas propriedades fisicas e quimicas do esmalte e dentina
Section A: Effects of bleaching agents on dental enamel Since the introduction of the nightguard vital bleaching technique using 10% carbamide peroxide (10% CP), reports have evaluated the effects of bleaching agents on human enamel. Evidences show that CP is able to alter the composition and morphology of enamel substrate. In order to reduce the adverse eff
Publicado em: 2007