Martins, R., B. Brás, I. Ferreira, L. Pereira, P. Barquinha, N. Correia, R. Costa, T. Busani, A. Gonçalves, and A. Pimentel Away from silicon era: the paper electronics. SPIE OPTO. International Society for Optics and Photonics, 2011.
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Martins, R., B. Bras, I. Ferreira, L. Pereira, P. Barquinha, N. Correia, R. Costa, T. Busani, A. Goncalves, A. Pimentel, and E. Fortunato. "
Away from silicon era: the paper electronics."
Oxide-Based Materials and Devices Ii. Eds. F. H. Teherani, D. C. Look, and D. J. Rogers. Vol. 7940. Proceedings of SPIE, 7940. 2011.
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Fernandes, Vítor H., and Teresa M. Quinteiro. "
Bilateral semidirect product decompositions of transformation monoids."
Semigroup Forum. 82 (2011): 271-287.
AbstractSummary: In this paper we consider the monoid $\mathcal {OR}_{n}$ of all full transformations on a chain with $n$ elements that preserve or reverse the orientation, as well as its submonoids $\mathcal {OD}_{n}$ of all order-preserving or order-reversing elements, $\mathcal {OP}_{n}$ of all orientation-preserving elements and $\mathcal {O}_{n}$ of all order-preserving elements. By making use of some well known presentations, we show that each of these four monoids is a quotient of a bilateral semidirect product of two of its remarkable submonoids.
Amaro, P., A. Surzhykov, F. Parente, P. Indelicato, and J. P. Santos. "
Calculation of two-photon decay rates of hydrogen-like ions by using B-polynomials."
Journal of Physics A: Mathematical and Theoretical. 44 (2011): 245302.
AbstractA new approach is laid out to investigate two-photon atomic transitions. It is based on the application of the finite-basis solutions constructed from the Bernstein polynomial (B-polynomial) sets. We show that such an approach provides a very promising route for the relativistic second-order (and even higher-order) calculations since it allows for analytical evaluation of the involved matrices elements. In order to illustrate possible applications of the method and to verify its accuracy, detailed calculations are performed for the 2 s 1/2 ‚Üí 1 s 1/2 transition in neutral hydrogen and hydrogen-like ions, which are compared with the theoretical predictions based on the well-established B-spline basis-set approach.
Martins, Rodrigo, Arokia Nathan, Raquel Barros, LuÍs Pereira, Pedro Barquinha, Nuno Correia, Ricardo Costa, Arman Ahnood, Isabel Ferreira, and Elvira Fortunato. "
Complementary metal oxide semiconductor technology with and on paper."
Advanced Materials. 23.39 (2011): 4491-4496.
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Carvalho, Carlos, Guilherme Lavareda, and Nuno Paulino. "
A DC-DC Step-Up mu-Power Converter for Energy Harvesting Applications, Using Maximum Power Point Tracking, Based on Fractional Open Circuit Voltage."
TECHNOLOGICAL INNOVATION FOR SUSTAINABILITY. Ed. LM CamarinhaMatos. Vol. 349. IFIP Advances in Information and Communication Technology, 349. Soc Collaborat Networks; IFIP WG 5.5 COVE CoOperation Infrastructure Virtual Enterprises & Elect Business; IEEE Ind Elect Soc; U2; Uninova, 2011. 510-517.
AbstractA DC-DC step-up micro power converter for solar energy harvesting applications is presented. The circuit is based on a switched-capacitor voltage tripler architecture with MOSFET capacitors, which results in an, area approximately eight times smaller than using MiM capacitors for the 0.131 mu m CMOS technology. In order to compensate for the loss of efficiency, due to the larger parasitic capacitances, a charge reutilization scheme is employed. The circuit is self-clocked, using a phase controller designed specifically to work with an amorphous silicon solar cell, in order to obtain the maximum available power from the cell. This will be done by tracking its maximum power point (MPPT) using the fractional open circuit voltage method. Electrical simulations of the circuit, together with an equivalent electrical model of an amorphous silicon solar cell, show that the circuit can deliver a power of 1132 mu W to the load, corresponding to a maximum efficiency of 66.81%.
Louren{\c c}o, João, Diogo Sousa, Bruno C. Teixeira, and Ricardo Dias. "
Detecting concurrency anomalies in transactional memory programs."
Comput. Sci. Inf. Syst.. 8 (2011).
AbstractSoftware transactional memory is a promising programming model that adapts many concepts borrowed from the databases world to control concurrent accesses to main memory (RAM). This paper discusses how to support revertible operations, such as memory allocation and release, within software libraries that will be used in software memory transactional contexts. The proposal is based in the extension of the transaction life cycle state diagram with new states associated to the execution of user-defined handlers. The proposed approach is evaluated in terms of functionality and performance by way of a use case study and performance tests. Results demonstrate that the proposal and its current implementation are flexible, generic and efficient
R., Neagu E., C. Dias, Lança M. Carmo, Igreja R., Inacio P., and Marat-Mendes J. N. "
Discrimination between Space Charge and Dipolar Contributions in Ferroelectric Polymers."
14th International Symposium on Electrets. International Symposium on Electrets. 2011.
AbstractThe final thermally stimulated discharge current method allows a better selection of the experimental conditions for sample polarization. By decreasing the ratio between the charging time and the discharging time, the apparent peak is of the same order of magnitude as the genuine peaks and there is only a partial overlap between then. Two peaks have been identified for polyamide 11, one associated with the glass transition around 60 °C and the second associated with the Curie transition around 96 °C.