Pulse Propagation
Mostrando 1-12 de 46 artigos, teses e dissertações.
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1. High-Speed Pulse Sequences through Semiconductor Optical Nonlinear Amplification and Buried Fiber Propagation
Abstract Microwave pulse bursts were obtained through optical domain intensity modulated microwave carriers, sliced by cascaded modulator technique, followed by non-linear semiconductor optical amplifier (SOA) pre-chirp. After 3 to 18 km of buried fiber propagation and photo detection, the microwave signals presented increased extinction ratio, up to 36 GHz,
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2020-09
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2. Propagation of vibrational modes in classical harmonic lattice with correlated disorder
Abstract: The vibrational modes with nonzero frequency are localized in harmonic lattice with disordered masses. In our work, we investigated numerically the propagation of vibrational energy in harmonic lattice with long-range correlated disordered masses, which are randomly distributed with power law spectrum S ( k ) ∝ k − α. For α = 0, a standar
An. Acad. Bras. Ciênc.. Publicado em: 01/07/2019
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3. Continuous flow phantom for the calibration of an ultrasonic transit-time flowmeter
INTRODUCTION: Ultrasound Transit-Time flowmeters are based on the fact that the time required for an ultrasound pulse to propagate through a given distance in a moving medium is a function of the vectorial sum of pulse propagation velocity and medium velocity. The most common application of this flowmeter in medicine is in the evaluation of blood flow in art
Rev. Bras. Eng. Bioméd.. Publicado em: 2014-03
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4. Simulação da propagação de ondas ultrassônicas longitudinais em materiais estruturais aeroespaciais / Simulating the propagation of longitudinal ultrasonic waves in aerospace structural materials
The use of composite materials in the aerospace industry is increasing due to its low ratio between density and mechanical strength. To perform non-destructive testing using ultrasound, it is necessary to know the sound velocity in these materials. It is not always possible to manufacture physical prototypes during the development of a project because of tim
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 10/08/2012
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5. Processamento de sinais de descargas parciais em tempo real com base em wavelets e seleção de coeficientes adaptativa espacialmente
On-line partial discharge (PD) analysis is a highly pursued feature due to the economy related to scheduled shutdowns, disassembling and transport. Nevertheless, on-site PD measurements are frequently limited by interferences found in high-voltage facilities, a situation that imposes the continued development of PD signal processing methods. In the last year
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 04/11/2011
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6. Single event transients in logic circuits - load and propagation induced pulse broadening
The generation and propagation of single event transients (SET) in logic gate chains is studied and modeled. Regarding SET generation, we investigate the dependence of the generated SET pulse width on the struck node capacitance. Rising node capacitance may lead to amplified pulse width, indicating that increasing load capacitance alone is not an option for
Publicado em: 2011
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7. MULTIPLICAÇÃO in vitro DE GENÓTIPOS DE Eucalyptus dunnii MAIDEN / MULTIPLICATION in vitro GENOTYPES OF Eucalyptus dunnii MAIDEN
Eucalyptus is a genus of great importance to the economy and production of various goods. Among the species of this genus, Eucalyptus dunnii Maiden stands out the importance, especially for the states of southern Brazil, to present a good growth and resistance to frost. However, this species presents problems for the production of seedlings by cloning, mainl
Publicado em: 2011
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8. Propriedades de transporte em meios granulares unidimensionais
Estudamos dois problemas envolvendo meios granulares, o transporte de calor em gases granulares viscosos e a propagação de pulsos mecânicos em cadeias granulares de anéis toróidais. Para estudar o transporte de calor em gases granulares, consideramos dois mecanismos de dissipação viscosa durante as colisões entre grãos. No primeiro mecanismo, a for�
Publicado em: 2011
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9. AnÃlise de performance de sÃlitons Ãpticos espaÃo-temporais em guia planar com nÃo-linearidade cÃbico quintica periodicamente modulada e circuitos lÃgicos operando nos regimes Kerr instantÃneo e relaxado. / Performance analysis of the spatio-temporal optical solitons in a planar guide with cubic quintic nonlinearity periodically modulated and logic circuits operating in regimes Kerr instantaneous and relaxed.
In this work, the propagation and stability of spatiotemporal optical solitons (or optical bullets) in a planar waveguide with periodically modulated cubic-quintic nonlinearity is presented numerically as a function of the amplitudes of modulation , the frequency of modulation and the propagation distance .With the objective of ensure the stability and preve
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 03/03/2010
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10. Propagação não linear de pulsos em estruturas 1D com band gap fotonico / Nonlinear pulse propagation in one-dimensional photonic band gap structures
The interaction of ultrashort optical pulses with photonic band gap materials has been studied by considering light propagation through one-dimensional photonic band gap structures, composed of a periodic multilayer stack of dielectric materials whose unitary cell consists of a pair of layers with different refractive indices n1and n2, respectively. One of t
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 17/08/2009
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11. Study of Laser pulses propagation through an ultrashort pulse amplifying systems for the development of an Öffner temporal stretcher / Estudo da propagação de pulsos Laser através de um sistema amplificador de pulsos ultracurtos para o desenvolvimento de um alargador temporal do tipo Öffner
The study of laser pulses propagation through an ultrashort pulses amplifying system containing dispersive and spectral modifying media was performed. The study emphasis was the development of an ultrashort pulse stretcher to replace the one inside a hybrid Ti:Sapphire/Cr:LiSAF CPA system operating at the Center for Lasers and Applications at IPEN/CNEN-SP. A
Publicado em: 2009
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12. Simuladores para medição de fluxo de liquidos por efeito doppler para controle de qualidade de equipamentos de ultra-sonografia / Doppler phantoms for flow measurement of liquids for ultrasond equipment quality control
In this work it is proposed the development of phantoms to allow de quality control of ultrasounds equipments functioning on the Doppler mode with national technology and accessible cost. The device consists of a hydraulic circuit with a peristaltic pump, mixture simulating human tissue, tubes simulating arteries and blood-mimicking fluid. The peristaltic di
Publicado em: 2008