Encontrados 16 documentos, a visualizar página 1 de 2
Minerais de ferro do Ordovícico Inferior do Anticlinal de Valongo
H. CoutoThe Lower Ordovician oolitic ironstones of Valongo anticline have abundant chamosite and/or siderite. True oolites are rare in the studied levels. Some pseudo-oolites are related to the presence of algae, as evidenced by cathodoluminescence. Iron came from emerged areas and deposited during transgression of Early Ordovician, in a shallow platform protected by barriers, with exhalativesedimentary vent in reducin...
Estudo de quartzos em catodoluminescência
H. Couto; A. Lourenço; F. BorgesThe application of cathodoluminescence microscopy to the study of quartz from different sources aims to show the importance of this technique to distinguish different generations of quartz, and to identify geochemical signatures with different origins. This study was applied to quartz of hydrothermal origin associated with gold mineralization, with lead-zinc epithermal mineralization associated with volcano-sed...
Thermoelectric micro converters for cooling and energy scavenging systems
Gonçalves, L. M.; Silva, A. F.; Alpuim, P.; Rocha, R. P.; Correia, J. H.; Couto, Carlos; Silva, H. R.This paper describes the fabrication process of thermoelectric microconverters, based on n-type bismuth telluride (Bi2Te3) and p-type antimony telluride (Sb2Te3) thin films. Materials are fabricated by thermal co-evaporation with thermoelectric properties comparable to those reported for the same materials in bulk form (used in conventional macro-scale Peltier modules). Absolute value of Seebeck coefficient in ...
A 2.4-GHz wireless sensor network for smart electronic shirts integration
Carmo, J. P.; Mendes, P. M.; Afonso, José A.; Correia, J. H.; Couto, CarlosA typical sensing module is composed of sensors, interface electronics, a radio-frequency (RF) CMOS transceiver and an associated antenna. A 2.4-GHz RF transceiver chip was fabricated in a UMC 0.18 μm CMOS process. The receiver has a sensibility of -60 dBm and consumes 6.3 mW from a 1.8 V supply. The transmitter delivers an output power of 0 dBm with a power consumption of 11.2 mW. Innovative topics concerning ...
Control of the deposition ratio of Bi2Te3 and Sb2Te3 in a vacuum evaporator for...
Gonçalves, L. M.; Rocha, J. G.; Correia, J. H.; Couto, CarlosThis article reports the main problem and the corresponding solution of the co-evaporation of Bi2Te3 and Sb2Te3 films for the fabrication of Peltier elements. This main problem consists in the control of the deposition rates of the two elements: Bi or Sb and Te, which have very different vapor pressures. The control of the deposition ratio was achieved by means of a PID controller, which permitted the fabricati...
HLA-B27 polymorphism and spondyloarthropathies.
Peixoto, M J; Gonzales, T; Spinola, H; Couto, A R; Mora, M Gantes; Brehm, A; Santos, M R; Garrett, F; Armas, J BrugesThe association of HLA-B27 with ankylosing spondylitis (AS), and other spondyloarthropathies (SpA), remains as one of the strongest between HLA molecules and human disease. Since it was reported, in 1973, it has been extensively studied in order to understand the underlying pathogenic mechanism. The objective of this article is to review the current knowledge on the structure and polymorphism of HLA-B27 molecul...
Optimization of Bi2Te3 and Sb2Te3 thin films deposited by co-evaporation on pol...
Gonçalves, L. M.; Alpuim, P.; Rowe, D. M.; Correia, J. H.; Couto, Carlos; Gao MinThe optimization of the deposition process for n-type Bi2Te3 and p-type Sb2Te3 semiconductor thin films for thermoelectric applications is reported. The films were deposited on a 25 μm thick flexible polyimide (Kapton) substrate by co-evaporation of Bi and Te, for the n-type element, and Sb and Te, for the p-type element.
A multi-chip-nodule micro-system for soil moisture measurements
Valente, A.; Morais, Raul; Correia, J. H.; Couto, CarlosThis study presents a Multi-Chip-Module-based (MCM) micro-system suited for irrigation control and management applications. The micro-system includes the soil moisture sensor and an analogue-to-digital converter with signal processing circuitry. The same basic fabrication concepts and materials which made microelectronics successful are now being adapted to making low-cost, small, and high-performance sensor sy...
A silicon probe with integrated microelectronics for soil moisture measurements
Valente, A.; Cunha, J. Boaventura; Correia, J. H.; Couto, CarlosThis work presents an on-chip silicon bulk-micromachined Soil Moisture Sensor (SMS) suited for irrigation control and management applications. The same basic fabrication concepts and materials, which made microelectronics successful, are now being adapted to making low-cost, small, high-performance sensor systems with integrated electronics on the same chip. As a result, this system-on-a-chip includes the SMS, ...
On-chip integrated silicon bulk-micromachined soil moisture sensor with electro...
Valente, A.; Correia, J. H.; Couto, CarlosThis paper presents an on-chip silicon bulkmicromachined Soil Moisture Sensor (SMS) for irrigation control in greenhouses. The system-on-a-chip includes the SMS, readout electronics, self-test, calibration facilities and a digital bus interface for external data transmission. Moreover, this low-cost device can be applied in several locations (e. g. per each plant root), and networked together with the 1-wire bu...
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