Microwave Substrates
Mostrando 1-12 de 12 artigos, teses e dissertações.
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1. Syntesis of Carbon Nanostructures Near Room Temperature Using Microwave PECVD
Carbon nanostructures (nanotubes, nanofibers and nanosponges) were synthesized onto Si (001) substrates using a microwave assisted plasma enhanced chemical vapor deposition (PECVD) from C2H2-Ar mixtures at low substrate temperatures (120 °C). Catalytic films (Ni and Cu) 3 nm thick were used. Different structures were formed, depending on the C2H2 partial pr
Mat. Res.. Publicado em: 2015-08
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2. Investigação da reação de Morita-Baylis-Hillman em reator de micro-ondas usando aldeídos aromáticos e isatina como eletrófilos: avaliação da atividade citotóxica em linhagem de células de leucemia promielocítica humanas (HL-60). / Investigation of Morita-Baylis-Hillman Reaction on Microwave Reactor using Aromatic Aldehydes and Isatin as Eletrophiles: Evaluation of Cytotoxic Activity in cell line human promyelocytic leukemia (HL-60).
In this work, we describe the investigation of the Morita-Baylis-Hillman reaction in microwave reactor, under closed vessel conditions to prepare 40 adducts, six novel, using 30 aromatic aldehydes and isatin as electrophiles and acrylonitrile (62a) , methyl acrylate (2), hydroxyethyl acrylate (62b), 2,2-dimethyl-1 ,3-dioxalyl acrylate (62c) and 2,3-dihydroxy
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 14/11/2012
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3. Produção de xilo-oligossacarídeos a partir de lignocelulósicos pré-tratados com xilanases imobilizadas e estabilzadas
Endoxylanase, an important industrial enzyme, cleaves ß-1,4-xylanosidic bounds in xylan chains, main plant hemicellulose component. Xylan can be explored to produce many products, among them xylo-oligosaccharides, XOS, made of xylose monomers (2 to 7 units). XOS are considered to be prebiotic ingredients and can improve humans health. XOS are produced by xy
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 28/02/2012
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4. Multilayer radar absorbing material processing by using polymeric nonwoven and conducting polymer
This study shows the processing of radar absorbing multilayer structures based on nonwoven substrates of polyacrylonitrile and poly (ethylene terephthalate) impregnated with a polyaniline and polyurethane mixture. Processed materials with different parameters - layer stacking and impregnated faces - were evaluated considering the incident radiation attenuati
Materials Research. Publicado em: 2008-09
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5. TRATAMENTO ELETRO TÉRMICO DE SUBSTRATOS DIELÉTRICOS PARA CIRCUITOS PLANARES DE MICROONDAS / ELECTRO-THERMAL TREATMENT OF DIELECTRIC SUBSTRATES FOR PLANAR MICROWAVE CIRCUITS
Diversos fatores têm atraído esforços para o desenvolvimento de novas estruturas para circuitos planares de microondas. Várias propostas são encontradas na literatura técnica, explorando diferentes formas de miniaturização dos circuitos, melhoria de eficiência de acoplamento, aumento de banda ou redução de perdas. Entre elas, encontra-se a utiliza
Publicado em: 2008
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6. Síntese de nanotubos de carbono orientados e aplicação na produção de pontas de AFM / Oriented growth of carbon nanotubes and application in production of afm Tips
In this work multi walled carbon nanotubes (MWCNT) were obtained. The growth presented high density nanotubes oriented perpendicularly to the substrate, with about 20 m length and diameters between 20 and 60 nm. Catalytic films containing iron were used. These films were deposited from solution of iron nitrate (Fe(NO3)3.9H2O) in ethyl alcohol with concentrat
Publicado em: 2008
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7. Estudo de nanotubos de carbono como fonte de elétron na geração de plasmas / Studies of carbon nanotubes as electron source for plasma generation
Aligned multiwalled carbon nanotubes films were produced by Microwave Plasma on Si/SiO2, Ti/TiN and quartz substrates. Ni and Fe nanoparticles were used as catalyst. The morphology and crystalline structures of the samples were analyzed by high resolution electron microscopy and by Raman spectroscopy. The Raman spectra have presented strong dependence on dia
Publicado em: 2006
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8. SYNTHESIS, REACTIVITY AND ANTIMICROBIAL ACTIVITY OF α-CHLORO β-ENAMINO ESTERS USING K-10 AND MICROWAVE IRRADIATION / SÍNTESE, REATIVIDADE E ATIVIDADE ANTIMICROBIANA DE β-ENAMINO ÉSTERES α-CLORADOS UTILIZANDO K-10 E IRRADIAÇÃO DE MICROONDAS
Enamino carbonylic compounds are important synthetic intermediates used in the synthesis of heterocycles and natural products. Our group of research has been dedicating much of our efforts to the development and implementation of simple and efficient methodologies to obtain β-enamino carbonylic compounds, mainly due to their functionality and ability to
Publicado em: 2005
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9. Tecnologia LOCOS utilizando nitretos de silicio depositados por ECR-CVD / LOCOS technology using silicon nitride deposited by ECR-CVD
Silicon nitride (SiNx) insulators for LOCOS applications have been deposited by RP/RTCVD and ECR-CVD at room temperature, at low pressure (5mTorr), with N2 flows of 2.5, 5, 10 and 20sccm with fixed SiH4/Ar flows of 200/20sccm with a microwave power of 1000W on SiO2-Pad/Si and Si substrates. SiNx/Si structures were obtained to analyze the physical characteris
Publicado em: 2005
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10. Filmes finos de LaNiO3 depositados sobre substratos monocristalinos pelo método dos precursores poliméricos. / LaNiO3 thin films deposited on single crystal substrates by the polimeric precursor method.
This work reports a systematic study on the deposition and characterization of LaNiO3 thin films. This material is a ceramic conductor and presents a near metallic behavior, and is interesting for capacitor electrodes application in memories systems, because of the reduction of fatigue behavior. The synthesis of the precursor resin was realized by the polyme
Publicado em: 2004
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11. Projeto e implementação de amplificadores distribuidos para recepção de sinais de alta velocidade
This work presents the design and implementation of hybrid distributed amplifiers, intendedfor advanced microwave systems that work with high velocity digital signals. Initially, approximated expressions for the computation of power gain and noise figure of these amplifiers were developed. Such equations allow the investigation of the frequency behavior and
Publicado em: 1991
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12. Amplificadores de baixo ruido em microondas
The theoretical part of this work deals with parameters that, direct or indirectly, are related with the design of microwave amplifiers. The study considered the S-parameters for 2-port devices (and their stability criteria) and also the noise characterization, since the main objective of this work was the minimization of noise in microwave amplifiers. Later
Publicado em: 1982