Leandro da Silva
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Previous Organizations / Institutes
The organizations / institutes from the scholar's other articles in the past ten years
Leandro da Silva has a total of 21 co-authors. Here are the top co-authors by number of shared publications:
- Alexandre Campos
Universidade do Estado de Santa Catarina
1 shared publication - André Luiz dos Santos
Centro Universitário Tupy, Brasil
1 shared publication - Douglas Pereira da Silva
Faculdade de Enfermagem Nova Esperança - FACENE
1 shared publication - Dries Van Thourhout
Ghent University - IMEC
1 shared publication - Enrique Giménez
Instituto Universitario de Tecnología de Materiales, Universitat Politècnica de València (UPV), Camino de Vera s/n, 46022 Valencia, Spain
1 shared publication Gilles F. Feutmba
Ghent University
1 shared publication
Latest Publications
- 29 June 2023
- Published by Optica Publishing Group in Optical Materials Express
- Vol. 13 (7) , 2120-2134
High frequency characterization of PZT thin-films deposited by chemical solution deposition on SOI for integrated high speed electro-optic modulators
The increasing demand for high data rates and low power consumption puts silicon photonics at the edge of its capabilities. The heterogeneous integration of optical ferro-electric materials on silicon enhances the functionality of the silicon on insulator (SOI) platform to meet these demands. Lead zirconate titanate (PZT) thin films with a large Pockels coefficient and good optical quality can be directly integrated on SOI waveguides for fast electro-optic modulators. In this work, the relative permittivity and dielectric loss of PZT thin films deposited by chemical solution deposition on SOI substrates are analyzed at high frequencies. We extract ε r =1650−2129 and tan (δ) = 0.170 − 0.209 for the PZT thin films in the frequency range 1-67GHz. We show the possibility of achieving bandwidths beyond 60GHz via a Mach-Zehnder modulator with V π = 7V, suitable for next generation data communication systems.
- 29 June 2023
- Published by Optica Publishing Group in Optical Materials Express
- Vol. 13 (7) , 2120-2134
High frequency characterization of PZT thin-films deposited by chemical solution deposition on SOI for integrated high speed electro-optic modulators
The increasing demand for high data rates and low power consumption puts silicon photonics at the edge of its capabilities. The heterogeneous integration of optical ferro-electric materials on silicon enhances the functionality of the silicon on insulator (SOI) platform to meet these demands. Lead zirconate titanate (PZT) thin films with a large Pockels coefficient and good optical quality can be directly integrated on SOI waveguides for fast electro-optic modulators. In this work, the relative permittivity and dielectric loss of PZT thin films deposited by chemical solution deposition on SOI substrates are analyzed at high frequencies. We extract ε r =1650−2129 and tan (δ) = 0.170 − 0.209 for the PZT thin films in the frequency range 1-67GHz. We show the possibility of achieving bandwidths beyond 60GHz via a Mach-Zehnder modulator with V π = 7V, suitable for next generation data communication systems.
- 20 April 2021
- Published by Institute of Electrical and Electronics Engineers (IEEE) in IEEE Journal of Emerging and Selected Topics in Power Electronics
- Vol. 10 (2) , 1479-1488
Capacitance Requirement Reduction in Single-Phase PFC With Adaptive Injection of Odd Harmonics
This article presents an adaptive harmonic injection approach for single-phase power factor correction (PFC) converters that reduce capacitance requirements and allow the use of smaller and more reliable film capacitors instead of electrolytic capacitors. Many applications require the converter’s rated power only during temporary intervals, whereas most of the time, the output power is much lower. In the proposed approach, the converter operates with a unity power factor below a given output power level. When the output power exceeds this value, then odd harmonics are linearly injected into the input current reference, up to the limits presented by IEC 61000-3-2. This approach reduces the voltage ripple across the power ripple buffering capacitor (PRBC), reducing the required capacitance value. The proposed approach is applied to the$\theta $ -converter using enhanced automatic power decoupling (EAPD) control. The dynamic model to control PRBC average voltage is presented. A 1-kW prototype is built to validate the approach using a metalized polypropylene film capacitor as the PRBC. At full power, injecting third and fifth harmonics, the PRBC capacitance can be reduced from 22 to$15~\mu \text {F}$ or 32%. It represents a further reduction in capacitance requirements for a converter that already requires low capacitance.- 20 April 2021
- Published by Institute of Electrical and Electronics Engineers (IEEE) in IEEE Journal of Emerging and Selected Topics in Power Electronics
- Vol. 10 (2) , 1479-1488
Capacitance Requirement Reduction in Single-Phase PFC With Adaptive Injection of Odd Harmonics
This article presents an adaptive harmonic injection approach for single-phase power factor correction (PFC) converters that reduce capacitance requirements and allow the use of smaller and more reliable film capacitors instead of electrolytic capacitors. Many applications require the converter’s rated power only during temporary intervals, whereas most of the time, the output power is much lower. In the proposed approach, the converter operates with a unity power factor below a given output power level. When the output power exceeds this value, then odd harmonics are linearly injected into the input current reference, up to the limits presented by IEC 61000-3-2. This approach reduces the voltage ripple across the power ripple buffering capacitor (PRBC), reducing the required capacitance value. The proposed approach is applied to the$\theta $ -converter using enhanced automatic power decoupling (EAPD) control. The dynamic model to control PRBC average voltage is presented. A 1-kW prototype is built to validate the approach using a metalized polypropylene film capacitor as the PRBC. At full power, injecting third and fifth harmonics, the PRBC capacitance can be reduced from 22 to$15~\mu \text {F}$ or 32%. It represents a further reduction in capacitance requirements for a converter that already requires low capacitance.- Open Access
- 6 December 2018
- Published by FapUNIFESP (SciELO) in Matéria (Rio de Janeiro)
- Vol. 23 (4)
Preparação de membranas de PHB por eletrofiação e caracterização para aplicações em engenharia tecidual
RESUMO Este trabalho tem como objetivo a preparação de mantas compostas por fibras do polímero biodegradável poli(3-hidroxibutirato) -(PHB) por meio da técnica de eletrofiação. Obtiveram-se mantas sob diferentes condições, variando-se o fluxo, a temperatura da solução, a tensão aplicada e a adição de um agente surfactante. O material obtido foi analisado por microscopia eletrônica de varredura (MEV), calorimetria exploratória diferencial (DSC), termogravimetria (TG), difratometria de raios-X (DRX) e viabilidade celular. A caracterização por MEV mostrou que os melhores resultados, apresentando as fibras com diâmetros constantes de 0,77 µm e sem a formação de grãos, foram atingidos nas seguintes condições: concentração da solução de 10% (m/v) em CF/DMF (9/1), fluxo da solução de 5,8 ml/h, tensão de 17 kV e adição de surfactante (dodecilsulfato de sódio, SDS). Os resultados mostraram que as variações de vazão, tensão e a adição de surfactante não influenciam muito o diâmetro médio das fibras, enquanto o aumento da temperatura diminui este parâmetro. No entanto, a adição de um agente surfactante deixa a manta mais densa e com poros interconectados, além de permitir a proliferação celular, sendo então indicada para produção de mantas para uso como arcabouço.
- 6 December 2018
- Published by FapUNIFESP (SciELO) in Matéria (Rio de Janeiro)
- Vol. 23 (4)
Open AccessPreparação de membranas de PHB por eletrofiação e caracterização para aplicações em engenharia tecidual
RESUMO Este trabalho tem como objetivo a preparação de mantas compostas por fibras do polímero biodegradável poli(3-hidroxibutirato) -(PHB) por meio da técnica de eletrofiação. Obtiveram-se mantas sob diferentes condições, variando-se o fluxo, a temperatura da solução, a tensão aplicada e a adição de um agente surfactante. O material obtido foi analisado por microscopia eletrônica de varredura (MEV), calorimetria exploratória diferencial (DSC), termogravimetria (TG), difratometria de raios-X (DRX) e viabilidade celular. A caracterização por MEV mostrou que os melhores resultados, apresentando as fibras com diâmetros constantes de 0,77 µm e sem a formação de grãos, foram atingidos nas seguintes condições: concentração da solução de 10% (m/v) em CF/DMF (9/1), fluxo da solução de 5,8 ml/h, tensão de 17 kV e adição de surfactante (dodecilsulfato de sódio, SDS). Os resultados mostraram que as variações de vazão, tensão e a adição de surfactante não influenciam muito o diâmetro médio das fibras, enquanto o aumento da temperatura diminui este parâmetro. No entanto, a adição de um agente surfactante deixa a manta mais densa e com poros interconectados, além de permitir a proliferação celular, sendo então indicada para produção de mantas para uso como arcabouço.
- 15 March 2017
- Published by Springer Nature
- p. 1-12
Robot Position Optimization Based on Joint Mean Torque Norm
- 15 March 2017
- Published by Springer Nature
- p. 1-12
Robot Position Optimization Based on Joint Mean Torque Norm