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Wyszukujesz frazę "Oliveira, J. P." wg kryterium: Autor


Wyświetlanie 1-9 z 9
Tytuł:
Co-design of a low-power RF receiver and piezoelectric energy harvesting power supply for a Wireless Sensor Node
Autorzy:
Mancelos, N
Correia, J
Oliveira, J. P.
Oliveira, L. B.
Powiązania:
https://bibliotekanauki.pl/articles/398018.pdf
Data publikacji:
2014
Wydawca:
Politechnika Łódzka. Wydział Mikroelektroniki i Informatyki
Tematy:
CMOS RF analog front-end
low-voltage wideband balun LNA
passive mixer
piezoelectric energy harvesting
active full bridge rectifier
LDO regulator
układ analogowy CMOS
balun szerokopasmowy
mikser pasywny
energia piezoelektryczna
prostownik aktywny
prostownik mostkowy
regulator LDO
Opis:
A low-voltage RF CMOS receiver front-end and an energy harvesting power circuit for a piezoelectric source are presented as a co-designed solution for a Wireless Sensor Node. A MOSFET-only Wideband balun LNA with noise cancelling and a 0.6 V supply voltage is designed in conjunction with a passive mixer. The passive mixer operates in current mode, allowing a minimal introduction of voltage noise and a good linearity. The receiver front-end reaches a total voltage conversion gain of 31 dB, a 0.1-5.2 GHZ bandwidth, an IIP3 value of -1.35 dBm, and a noise figure inferior to 9 dB. The total power consumption is 1.95 mW. The energy harvesting power circuit consists of an active full bridge cross-coupled rectifier followed by a low-dropout (LDO) regulator, and it is able to guarantee a power output of 6 mW with a regulated output voltage of 0.6 V, for typical vibration patterns.
Źródło:
International Journal of Microelectronics and Computer Science; 2014, 5, 4; 136-143
2080-8755
2353-9607
Pojawia się w:
International Journal of Microelectronics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cascode amplifiers with low-gain variability and gain enhancement using a body-biasing technique
Autorzy:
Pereira, N
Oliveira, L. B.
Goes, J.
Oliveira, J. P.
Powiązania:
https://bibliotekanauki.pl/articles/398063.pdf
Data publikacji:
2013
Wydawca:
Politechnika Łódzka. Wydział Mikroelektroniki i Informatyki
Tematy:
amplifier
body-biasing
cascode
CMOS analog circuits
PVT compensation
wzmacniacz
kaskoda
układy analogowe CMOS
kompensacja PVT
Opis:
This paper presents a simple circuit technique to reduce gain variability with PVT variations in cascode amplifiers using a body-biasing scheme, while enhancing the overall gain of the amplifier. Simulation results of a standard telescopic-cascode amplifier, in two different nanoscale CMOS technologies (130 nm and 65 nm) show that the proposed compensated circuit amplifier exhibits a (DC) gain variability smaller (below ± 0.5 dB) than the original (uncompensated) circuit, while reaching a gain enhancement of about 3 dB. The required auxiliary biasing circuit dissipates around 5% of the main amplifier circuit.
Źródło:
International Journal of Microelectronics and Computer Science; 2013, 4, 3; 98-102
2080-8755
2353-9607
Pojawia się w:
International Journal of Microelectronics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Simplified Design Methodology for MOSFET-Only Wideband Mixer
Autorzy:
Ortigueira, E.
Bastos, I.
Oliveira, L. B.
Oliveira, J. P.
Goes, J.
Powiązania:
https://bibliotekanauki.pl/articles/227194.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
CMOS mixers
MOSFET-only circuits
Gilbert cell
active mixers
wideband mixers
Opis:
In this paper we present a MOSFET-only implementation of a wideband Gilbert Cell. The circuit uses a commongate topology for a wideband input match, capable to cover the Wireless Medical Telemetry Service (WMTS) frequency bands of 600 MHz and 1.4 GHz. In this circuit the load resistors are replaced by transistors in triode region, to reduce area and cost, and minimize the effects of process and supply variations and mismatches. In addition, we obtain a higher gain for the same DC voltage drop, with a reduced impact on the noise figure (NF). The performance of this topology is compared with that of a conventional mixer with load resistors. Simulation results show that a peak gain of 20.6 dB (about 6 dB improvement) and a NF about of 11 dB for the 600 MHz band. The total power consumption is 3.6 mW from a 1.2 V supply.
Źródło:
International Journal of Electronics and Telecommunications; 2011, 57, 4; 503-509
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ultra-low-voltage LNA with high gain and low noise figure
Autorzy:
Bastos, I.
Oliveira, L. B.
Oliveira, J. P.
Goes, J.
Silva, M. M.
Powiązania:
https://bibliotekanauki.pl/articles/397785.pdf
Data publikacji:
2013
Wydawca:
Politechnika Łódzka. Wydział Mikroelektroniki i Informatyki
Tematy:
LNA
CMOS
noise cancellation
redukcja szumów
Opis:
We present a balun LNA with noise and distortion cancellation using double feedforward. A common-gate and a common-source stage are combined, and their resistive loads are replaced by transistors biased close to saturation to allows low supply voltage, without gain degradation. The proposed feedforward boosts the LNA gain and reduces the noise figure (NF). Simulation results with a 130 nm CMOS technology show that the gain is up to 24 dB and the NF is below 3.2 dB. The total power dissipation is 2.25 mW, leading to an FoM of 6.4 mW-1 with 0.6 V supply.
Źródło:
International Journal of Microelectronics and Computer Science; 2013, 4, 3; 124-128
2080-8755
2353-9607
Pojawia się w:
International Journal of Microelectronics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Charge-Ordering and Magnetoelastic Coupling Effects on the Magnetocaloric Properties of Manganites
Autorzy:
Reis, M. S.
Gomes, A. M.
Araújo, J. P.
Tavares, P. B.
Amaral, J. S.
Oliveira, I. S.
Amaral, V. S.
Powiązania:
https://bibliotekanauki.pl/articles/2037124.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.30.Kz
75.80.+q
Opis:
A study of the magnetocaloric properties of La$\text{}_{1-x-y}$Y$\text{}_{y}$Ca$\text{}_{x}$MnO$\text{}_{3}$, La$\text{}_{1-x}$Cd$\text{}_{x}$MnO$\text{}_{3}$, and Pr$\text{}_{1-x}$Ca$\text{}_{x}$MnO$\text{}_{3}$ manganites with ferromagnetic and charge-ordered states is presented. The ferromagnetic lanthanum manganites show a negative entropy change peakΔ S under the application of a magnetic field at the Curie temperature. However, the magnetoelastic coupling effects lead to a first-order paramagnetic-ferromagn etic transition and an increasedΔ S compared to simple ferromagnets. This effect is analyzed in the framework of the Landau theory of phase transitions which shows a comparable influence of the magnetoelastic couplings and the ordinary magnetic ordering effect. The Pr$\text{}_{1-x}$Ca$\text{}_{x}$MnO $\text{}_{3}$ system shows a rich electric and magnetic phase diagram, with a ferromagnetic insulator phase for 0.15
Źródło:
Acta Physica Polonica A; 2004, 105, 1-2; 163-171
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal assisted switching magnetic tunnel junctions as FPGA memory elements
Autorzy:
Silva, V.
Fernandes, J. R.
Oliveira, L. B.
Neto, H. C.
Ferreira, R.
Freitas, S.
Freitas, P. P.
Powiązania:
https://bibliotekanauki.pl/articles/397855.pdf
Data publikacji:
2010
Wydawca:
Politechnika Łódzka. Wydział Mikroelektroniki i Informatyki
Tematy:
MRAM (oporność magnetyczna pamięci o dostępie swobodnym)
MTJ (magnetyczny tunel połączeń)
pisanie projektów (programów)
FIMS (pole indukowane magnetycznym przełącznikiem)
MRAM (magnetoresistive random access memory)
MTJ (magnetic tunnel junction)
writing schemes
FIMS (field induced magnetic switching)
TAS (thermal assisted switching)
STT
Opis:
This paper presents our research and development work on new circuits and topologies based on Magnetic RAM for use as configuration memory elements of reconfigurable arrays. MRAM provides non volatility with cell areas and with access speeds comparable to those of SRAM and with lower process complexity than FLASH memories. The new memory cells take advantage of the Thermal Assisted Switching (TAS) writing technique to solve the drawbacks of the more common Field Induced Magnetic Switching writing technique. The CMOS circuit structures to implement the main components for reading and writing the MTJ cells have been developed, characterized and evaluated. A scaled down prototype of a coarse grain reconfigurable array that employs the TAS-MRAM elements as configuration memory has been designed and electrically simulated pre- and post- layout. The results obtained for all the circuit elements, namely the storage cells and the current generators, indicate that the new configuration memory cells can provide a very promising technological solution for run-time reconfigurable hardware devices. The prototype has been manufactured using a standard process 0.35μm 4-Metal CMOS process technology and should be under test in the foreseeable future.
Źródło:
International Journal of Microelectronics and Computer Science; 2010, 1, 1; 31-36
2080-8755
2353-9607
Pojawia się w:
International Journal of Microelectronics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dielectric properties of papaya seeds from 75 kHz to 5 MHz
Autorzy:
Berbert, P.A.
Soares, K.J.
Moura, E.E.
Berbert-Molina, M.A.
Oliveira, M.T.R.
Martinazzo, A.P.
Powiązania:
https://bibliotekanauki.pl/articles/2082500.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
Carica papaya L.
dielectric loss factor
moisture content
relative permittivity
seed bulk density
Opis:
The object of this work was to study the dielectric properties of papaya seeds of the Golden cultivar and seeds of two papaya hybrids, Tainung and Calimosa, in the frequency range from 75 kHz to 5 MHz at four levels of bulk density, and with moisture contents ranging from 6 to 23% wet basis. The relative permittivity and the loss factor of the seeds were measured using a precision LCR meter, and their relationship with the variable frequency of the oscillating electric field, the seed moisture content and bulk density, and the cultivar/hybrid type were established. Relative permittivity for each value of the moisture content was reduced regularly as the frequency increased. Abrupt changes in the slopes of the curves demonstrating the relationship between the relative permittivity and the loss factor, and the moisture content were considered an indication of changes in the water sorption mechanisms occurring within the seed. The relationship between the relative permittivity and the loss factor, and bulk density was represented by linear functions with positive slopes. The effect of the cultivar or hybrid types on the relative permittivity and the loss factor revealed that seeds of the Golden cultivar and the Tainung hybrid exhibited similar relative permittivity values in the whole frequency range studied, in contrast to seeds of the Calimosa hybrid.
Źródło:
International Agrophysics; 2019, 33, 2; 185-192
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Geoelectric method applied in correlation between physical characteristics and electrical properties of the soil
Autorzy:
Filho, A. M. S.
Silva, C. L. B.
Oliveira, M. A. A.
Pires, T. G.
Alves, A. J.
Calixto, W. P.
Narciso, M. G.
Powiązania:
https://bibliotekanauki.pl/articles/136150.pdf
Data publikacji:
2017
Wydawca:
EEEIC International Barbara Leonowicz Szabłowska
Tematy:
geoelectrical prospecting
apparent
electrical resistivity
soil compaction
moisture content
Opis:
This paper presents the study of the relationship between electrical properties and physical characteristics of the soil. Measures of apparent electrical resistivity of the soil were made for different types of soil, varying moisture content gradually while maintaining a constant compaction, and then varying the compaction and relating it to a constant humidity. Development of a correlation surface is proposed in order to identify granulometry of the soil from moisture and compaction measurements. For the study of spatial variability, two areas were chosen to allow the change of moisture content and compaction in order to verify the measurement capacity of apparent electrical resistivity of the soil as methodology to identify change in soil dynamics. Results obtained show correlations among apparent electrical resistivity of the soil, moisture, soil compaction and clay content.
Źródło:
Transactions on Environment and Electrical Engineering; 2017, 2, 2; 37-44
2450-5730
Pojawia się w:
Transactions on Environment and Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phytochemical potential of Ficus species for the control of the phytonematode Meloidogyne javanica
Autorzy:
Alves, J.R.
De Assis, J.N.
Padua, C.C.A.
Balbino, H.M.
Lima, L.L.
De Souza Gouveia, A.
Vital, C.E.
Buonicontro, D.S.
De Freitas, L.G.
Leite, J.P.V.
De Oliveira Ramos, H.J.
Powiązania:
https://bibliotekanauki.pl/articles/2082765.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
gas chromatography/mass spectrometry (GC/MS)
metabolite profiling
pest
control
phytochemistry
Opis:
Root-knot nematodes, genus Meloidogyne, are among the most plant damaging pathogens worldwide. The action of natural products against plant pathogens has been investigated to assess their effectiveness in the control of diseases. Thus, the present study aimed to evaluate the phytochemistry potential of the Ficus species for the control of Meloidogyne javanica. In vitro inhibitory activity assays were performed with crude ethanolic extracts of leaves and branches from 10 Ficus species. Among these, Ficus carica extracts exhibited strong paralysis activity against second stage juveniles (J2) (EC50 = 134.90 μg ∙ ml–1 ), after 72 hours. In addition, high efficacy was observed in egg-hatching inhibition at different embryonic stages. Microscopy analysis revealed severe morphological alterations in the nematode tissues at the J2 stage, as well as immotility of juveniles released from eggs in the presence of F. carica extracts. The efficacy of the treatments for the other species was very low. These differences were supported by the variation in the compound classes, mainly for alkaloids and metabolite profiles by Gas Chromatography/Mass Spectrometry (GC/MS) when F. carica was compared with the other species. The results indicated that F. carica is a promising source for the isolation and identification of molecules capable of acting in the control of M. javanica.
Źródło:
Journal of Plant Protection Research; 2020, 60, 2; 193-206
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-9 z 9

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