Export 2079 results:
Sort by: Author Title Type [ Year  (Desc)]
2013
Pinto, Joana V., Rita Branquinho, Pedro Barquinha, Eduardo Alves, Rodrigo Martins, and Elvira Fortunato. "{Extended-gate ISFETs based on sputtered amorphous oxides}." IEEE/OSA Journal of Display Technology. 9 (2013): 729-734. Abstract

We present the results obtained with an extended-gate ISFET totally based on amorphous oxides (GIZO as the semiconductor, {\textless}formula formulatype="inline"{\textgreater}{\textless}tex Notation="TeX"{\textgreater}{\$}{\{}hbox{\{}Ta{\}}{\}}{\_}{\{}2{\}}{\{}hbox{\{}O{\}}{\}}{\_}{\{}5{\}}{\{}hbox{\{}:SiO{\}}{\}}{\_}{\{}2{\}}{\$}{\textless}/tex{\textgreater} {\textless}/formula{\textgreater} as the dielectric and {\textless}formula formulatype="inline"{\textgreater}{\textless}tex Notation="TeX"{\textgreater}{\$}{\{}hbox{\{}Ta{\}}{\}}{\_}{\{}2{\}}{\{}hbox{\{}O{\}}{\}}{\_}{\{}5{\}}{\$}{\textless}/tex{\textgreater} {\textless}/formula{\textgreater} as the sensitive layer). A full characterization of the device was performed with constant ionic strength pH buffer solutions, revealing a sensitivity of 40 mV/pH with small hysteresis, and good linearity in the pH 4{&}{\#}x2013;pH 10 range buffer solutions. These results clearly show that it is possible to produce room-temperature disposable and low cost bio-sensors.

Cruz, M. M., R. C. Silva, JV Pinto, R. P. Borges, N. Franco, and A. Casaca. "{Formation of oriented nickel aggregates in rutile single crystals by Ni implantation}." Journal of Magnetism and Magnetic Materials. 340 (2013): 102-108. AbstractWebsite

The magnetic and electrical properties of Ni implanted single crystalline TiO2 rutile were studied for nominal implanted fluences between 0.5?1017 cm−2 and 2.0?1017 cm−2 with 150 keV energy, corre- sponding to maximum atomic concentrations between 9 at{%} and 27 at{%} at 65 nm depth, in order to study the formation of metallic oriented aggregates. The results indicate that the as implanted crystals exhibit superparamagnetic behavior for the two higher fluences, which is attributed to the formation of nanosized nickel clusters with an average size related with the implanted concentration, while only paramagnetic behavior is observed for the lowest fluence. Annealing at 1073 K induces the aggregation of the implanted nickel and enhances the magnetization in all samples. The associated anisotropic behavior indicates preferred orientations of the nickel aggregates in the rutile lattice consistent with Rutherford backscattering spectrometry—channelling results. Electrical conductivity displays anisotropic behavior but no magnetoresistive effects were detected.

Guerreiro, B. J., P. Batista, C. Silvestre, and P. Oliveira. "{Globally Asymptotically Stable Sensor-based Simultaneous Localization and Mapping}." Transactions on Robotics. 29 (2013). Abstract
n/a
Guerreiro, B. J., P. Batista, C. Silvestre, and P. Oliveira. "{Globally Asymptotically Stable Sensor-based Simultaneous Localization and Mapping}." Transactions on Robotics. 29 (2013). Abstract
n/a
Gawande, Manoj B., Anuj K. Rathi, Paula S. Branco, T. M. Potewar, Alexandre Velhinho, Isabel D. Nogueira, Alexander Tolstoguzov, Amjad C. A. Ghumman, and Orlando M. N. D. Teodoro. "{Nano-MgO-ZrO2 Mixed Metal oxides: Characterization by SIMS and application in the reduction of carbonyl compounds and in multicomponent reactions}." RSC Advances. 3 (2013): 3611-3617. Abstract

A nano-sized Magnesia–Zirconia (nano-MgO–ZrO2) catalyst was prepared by a simple ultradilution co-precipitation method and by using inexpensive precursors. The nano-MgO–ZrO2 was extensively characterized by SIMS together with other analytical techniques such as X-ray diffraction (XRD) and transmission electron microscopy (TEM). The nano-MgO–ZrO2 catalyst proved to be very efficient for the reduction of carbonyl compounds and multicomponent reactions under mild reaction conditions. The recyclability and reusability of the nano-MgO–ZrO2 catalyst has been tested.

Figueiredo, V., JV Pinto, J. Deuermeier, R. Barros, E. Alves, R. Martins, and E. Fortunato. "{p-Type Cu O Thin-Film Transistors Produced by Thermal Oxidation}." Journal of Display Technology. 9 (2013): 735-740. Abstract

Thin-films of copper oxide Cu O were produced by thermal oxidation of metallic copper (Cu) at different tempera- tures (150–450 C). The films produced at temperatures of 200, 250 and 300 C showed high Hall motilities of 2.2, 1.9 and 1.6 cm V s , respectively. Single Cu O phases were obtained at 200 Cand its conversion toCuO starts at 250 C. For lower thick- nesses 40 nm, the films oxidized at 250 Cshowed a complete conversion to CuO phase. Successful thin-film transistors (TFTs) were produce by thermal oxidation of a 20 nm Cu film, obtaining p-type Cu O (at 200 C) and CuO (at 250 C) with On/Off ratios of 6 10 and 1 10 , respectively.

Parthiban, Shanmugam, Elamurugu Elangovan, Pradipta K. Nayak, Alexandra Gonçalves, Daniela Nunes, Lu\'ıs Pereira, Pedro Barquinha, Tito Busani, Elvira Fortunato, and Rodrigo Martins. "{Performances of Microcrystalline Zinc Tin Oxide Thin-Film Transistors Processed by Spray Pyrolysis}." 9 (2013): 825-831. Abstract
n/a
Branquinho, Rita, Joana V. Pinto, Tito Busani, Pedro Barquinha, Luis Pereira, Pedro Viana Baptista, Rodrigo Martins, and Elvira Fortunato. "{Plastic Compatible Sputtered Ta O Sensitive Layer for Oxide Semiconductor TFT Sensors}." 9 (2013): 723-728. Abstract
n/a
Branquinho, Rita, Joana V. Pinto, Tito Busani, Pedro Barquinha, Luis Pereira, Pedro Viana Baptista, Rodrigo Martins, and Elvira Fortunato. "{Plastic Compatible Sputtered Ta O Sensitive Layer for Oxide Semiconductor TFT Sensors}." Journal of Display Technology. 9 (2013): 723-728. Abstract

The effect of post-deposition annealing temperature on the pH sensitivity of room temperature RF sputtered Ta O was investigated. Structural and morphological features of these films were analyzed before and after annealing at various tem- peratures. The deposited films are amorphous up to 600 Cand crystallize at 700 C in an orthorhombic phase. Electrolyte-insu- lator-semiconductor (EIS) field effect based sensors with an amor- phousTa O sensing layer showed pHsensitivity above 50 mV/pH. For sensors annealed above 200 C pH sensitivity decreased with increasing temperature. Stabilized sensor response andmaximum pHsensitivitywas achieved after low temperature annealing at 200 C, which is compatible with the use of polymeric substrates and application as sensitive layer in oxides TFT-based sensors

Branquinho, Rita, Joana V. Pinto, Tito Busani, Pedro Barquinha, Luis Pereira, Pedro Viana Baptista, Rodrigo Martins, and Elvira Fortunato. "{Plastic compatible sputtered Ta2O5 sensitive layer for oxide semiconductor tft sensors}." IEEE/OSA Journal of Display Technology. 9 (2013): 723-728. AbstractWebsite

The effect of post-deposition annealing temperature on the pH sensitivity of room temperature RF sputtered Ta2O5 was investigated. Structural and morphological features of these films were analyzed before and after annealing at various temperatures. The deposited films are amorphous up to 600 °C and crystallize at 700 °C in an orthorhombic phase. Electrolyte-insulator-semiconductor (EIS) field effect based sensors with an amorphous Ta2O5 sensing layer showed pH sensitivity above 50 mV/pH. For sensors annealed above 200 °C pH sensitivity decreased with increasing temperature. Stabilized sensor response and maximum pH sensitivity was achieved after low temperature annealing at 200 °C, which is compatible with the use of polymeric substrates and application as sensitive layer in oxides TFT-based sensors.

a.M. Ramos, S. Pereira, M. T. Cidade, G. Pereira, R. Branquinho, L. Pereira, R. Martins, and E. Fortunato. "{Preparation and characterization of cellulose nanocomposite hydrogels as functional electrolytes}." Solid State Ionics. 242 (2013): 26-32. AbstractWebsite
n/a
Ramos, A. M., S. Pereira, M. T. Cidade, G. Pereira, R. Branquinho, L. Pereira, R. Martins, and E. Fortunato. "{Preparation and characterization of cellulose nanocomposite hydrogels as functional electrolytes}." Solid State Ionics. 242 (2013): 26-32. AbstractWebsite

In this work Laponite was combined with a modified abundant natural polymer, (caboxymethyl cellulose), acrylic sodium salt polymer and lithium perchlorate aiming to produce inexpensive and sustainable nanocomposite electrolytes for functional electrochemical devices. Optical, electrochemical, structural, morphological and rheological characterization was performed in order to evaluate their properties and potential advantages as electrolyte. It was verified that the addition of Laponite led to an ionic conductivity at room temperature (25 C) in the range of 6 to 9 ?? 10- 5 Scm - 1 this value being then determined by the composition of the nanocomposite. These electrolytes were applied to electrochromic devices using evaporated nickel oxide thin film as the electrochromic layer. The devices exhibited a significant transmittance modulation that exceeds 45 {%} at 600 nm. ?? 2013 Elsevier B.V.

Engineering, Tissue, Cell Based, Campus D. E. Gualtar, Maria Manuela, Estima Gomes, A. N. A. Rita, Cruz Duarte, Sentido D. E. Fornecer, U. M. A. Estrutura, Porosa E. Interconectada, and Suporte D. E. A. O. Crescimento. "{PT 106220}." 106220 (2013). Abstract
n/a
Engineering, Tissue, Cell Based, Campus D. E. Gualtar, Maria Manuela, Estima Gomes, A. N. A. Rita, Cruz Duarte, Sentido D. E. Fornecer, U. M. A. Estrutura, Porosa E. Interconectada, and Suporte D. E. A. O. Crescimento. "{PT 106220}." 106220 (2013). Abstract
n/a
Machado, J., A. Blanco, P. Fonte, D. Galaviz, L. Lopes, Ferreira R. Marques, and P. Teubig. "{Simulations of a new detection concept for high-energy neutrons based on timing RPCs}." Journal of Instrumentation. 8 (2013): P07020. AbstractWebsite
n/a
Martí, Antonio, Elisa Antolín, Pablo {García Linares}, Iñigo Ramiro, Irene Artacho, Esther López, Estela Hernández, Manuel J. Mendes, Alex Mellor, Ignacio Tobías, David {Fuertes Marrón}, Cesar Tablero, Ana B. Cristóbal, Christopher G. Bailey, Maria Gonzalez, Michael Yakes, Mathew P. Lumb, Robert Walters, and Antonio Luque. "{Six not-so-easy pieces in intermediate band solar cell research}." Journal of Photonics for Energy. 3 (2013): 31299. AbstractWebsite

Abstract.  The concept of intermediate band solar cell (IBSC) is, apparently, simple to grasp. However, since the idea was proposed, our understanding has improved and some concepts can now be explained more clearly than when the concept was initially introduced. Clarifying these concepts is important, even if they are well known for the advanced researcher, so that research efforts can be driven in the right direction from the start. The six pieces of this work are: Does a miniband need to be formed when the IBSC is implemented with quantum dots? What are the problems for each of the main practical approaches that exist today? What are the simplest experimental techniques to demonstrate whether an IBSC is working as such or not? What is the issue with the absorption coefficient overlap and the Mott's transition? What would the best system be, if any?

2012
Bruno Pedras, Vitor Rosa, Richard Welter, Carlos Lodeiro, and Teresa Aviles. "{New quinoline alpha-diimine ligands as fluorescent probes for metal ions: Ultrasound-assisted and conventional synthetic methods}." {INORGANICA CHIMICA ACTA}. {381} (2012): {143-149}. Abstract

{Three new emissive 8-aminoquinoline derived probes (1)-(3) and one dinuclear Zn(II) complex (4) were synthesized and fully characterized. Their absorption spectra show maxima at 310-336 nm, and fluorescence emission between 456 and 498 nm. Compound (1) was characterized by single crystal X-ray diffraction. The effect upon Zn(II) and Cu(II) coordination to compounds (1)-(3) was studied by monitoring the changes in absorption and fluorescence spectra, and complemented by calculation of metal-ligand stability constants. The results indicate that compound (3) is the one that presents the most favorable geometry for coordinating two metal cations, fact that is confirmed by the synthesis of the dinuclear complex (4), with similar molecular geometry. (C) 2011 Elsevier B.V. All rights reserved.}

Veigas, Bruno, Jorge M. Jacob, Mafalda N. Costa, David S. Santos, Miguel Viveiros, Joao Inacio, Rodrigo Martins, Pedro Barquinha, Elvira Fortunato, and Pedro Viana Baptista. "Gold on paper-paper platform for Au-nanoprobe TB detection." Lab on a Chip. 12 (2012): 4802-4808. AbstractWebsite
n/a
Valerio, P., R. J. C. Silva, M. F. Araujo, A. M. M. Soares, and L. Barros. "A multianalytical approach to study the Phoenician bronze technology in the Iberian Peninsula-A view from Quinta do Almaraz." Materials Characterization. 67 (2012): 74-82. Abstract
n/a
Boavida, Nuno, and António Brandão Moniz Research and development expenditure in the business sector as indicator of knowledge economy: the Portuguese experience. Universidade Nova de Lisboa, IET-Research on Enterprise and Work Innovation, Faculty of Science and Technology, 2012. Abstract

The objective of the paper is to help to understand recent changes in the structure of R&D activities, by analyzing data on the expenditure of the business sector in research and development (R&D). The results are framed in an international context, through comparison with indicators from the most developed countries, divided by technological intensity and economic activity. The study reveals that the indicators of Portuguese R&D expenditure in the business sector are closely linked both to fiscal policy and to high foreign direct investment in knowledge-intensive industries. It also links these indicators to phenomena such as the abundance of skilled labor in pharmaceutical industries and the government intervention in some sectors of the economy (namely health and rail transportation).

Guerreiro, B. J., P. Batista, C. Silvestre, and P. Oliveira. "{Sensor-based Simultaneous Localization and Mapping – Part I: GAS Robocentric Filter}." American Control Conference (ACC), 2012. 2012. 6352-6357. Abstract
n/a
Guerreiro, B. J., P. Batista, C. Silvestre, and P. Oliveira. "{Sensor-based Simultaneous Localization and Mapping – Part I: GAS Robocentric Filter}." American Control Conference (ACC), 2012. 2012. 6352-6357. Abstract
n/a
Guerreiro, B. J., P. Batista, C. Silvestre, and P. Oliveira. "{Sensor-based Simultaneous Localization and Mapping – Part II: Online Inertial Map and Trajectory Estimation}." American Control Conference (ACC), 2012. 2012. 6334-6339. Abstract
n/a
Guerreiro, B. J., P. Batista, C. Silvestre, and P. Oliveira. "{Sensor-based Simultaneous Localization and Mapping – Part II: Online Inertial Map and Trajectory Estimation}." American Control Conference (ACC), 2012. 2012. 6334-6339. Abstract
n/a
Fortunato, E., P. Barquinha, and R. Martins. "Oxide Semiconductor Thin-Film Transistors: A Review of Recent Advances." Advanced Materials. 24 (2012): 2945-2986. AbstractWebsite
n/a
loading