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Cluj-Napoca, Romania

Franklin H.,University of Le Havre | Derible S.,University of Le Havre | Popa C.,National Institute for Research
Journal of the Acoustical Society of America | Year: 2010

A method for estimating the strength of the slow wave in the modes propagating in porous layers is presented. It is based upon expansions on transition terms which are linear combinations of the reflection and transmission coefficients. Suitable forms of these coefficients are needed and it is shown how they can be obtained. Both open pore and sealed pore boundary conditions are investigated. It is shown that the zeroth-order and the first-order terms of the expansions suffice to describe accurately the modes and to estimate the strength of the slow wave. Approximations of the absorption coefficient by the porous layer can be deduced. Angles of incidence above and below the critical angle of the shear wave are considered. Comparisons between theory and experiments for the two types of boundary conditions are presented at normal incidence for the transition terms. © 2010 Acoustical Society of America. Source


Sima V.,National Institute for Research
15th International Conference on System Theory, Control and Computing, ICSTCC 2011 | Year: 2011

The latest developments of the SLICOT Library and associated tools are discussed, and issues related to its future evolution are summarized. Structure-exploiting solvers for skew-Hamiltonian/Hamiltonian matrix pencils have been added. Possible applications include the computation of L ∞-or H ∞-norms of linear time-invariant multivariable systems, and solution of algebraic matrix Riccati equations. © 2011 Faculty of Auto Control. Source


Belean B.,Technical University of Cluj Napoca | Belean B.,National Institute for Research | Borda M.,Technical University of Cluj Napoca | Le Gal B.,University of Bordeaux 1 | Terebes R.,Technical University of Cluj Napoca
Computerized Medical Imaging and Graphics | Year: 2012

Automation is an open subject in DNA microarray image processing, aiming reliable gene expression estimation. The paper presents a novel shock filter based approach for automatic microarray grid alignment. The proposed method brings up significantly reduced computational complexity compared to state of the art approaches, while similar results in terms of accuracy are achieved. Based on this approach, we also propose an FPGA based system for microarray image analysis that eliminates the shortcomings of existing software platforms: user intervention, increased computational time and cost. Our system includes application-specific architectures which involve algorithm parallelization, aiming fast and automated cDNA microarray image processing. The proposed automated image processing chain is implemented both on a general purpose processor and using the developed hardware architectures as co-processors in a FPGA based system. The comparative results included in the last section show that an important gain in terms of computational time is obtained using hardware based implementations. © 2012 Elsevier Ltd. Source


Kovacs K.,National Institute for Research | Tosa V.,National Institute for Research
Journal of Modern Optics | Year: 2010

We present a method to trace quantum trajectories of electrons in a high-order harmonic generation process. The method relies on the saddle-point technique and, unlike previously developed analytical techniques, it enables an arbitrary variation in time of the driving fields. The trajectory phases yield information about phase-matching conditions at the optical cycle level, especially useful in investigating attosecond pulse generation. Specially prepared laser pulses, as well as propagation effects can be included in these phase-matching calculations. The method can handle both one- and two-dimensional electron trajectories produced by corresponding driving fields. We show the potentials of the method by calculating trajectories and phase-matching conditions for a polarization gate configuration proposed recently [Altucci, C.; Esposito, R.; Tosa, V.; Velotta, R. Opt. Lett. 2008, 33, 2943-2945.] to obtain isolated attosecond pulse from multi-cycle laser pulses. © 2010 Taylor & Francis. Source


Buimaga-Iarinca L.,National Institute for Research | Morari C.,National Institute for Research
Journal of Physical Chemistry C | Year: 2013

The physical properties of cysteine clusters formed on the Au(110)-(1 × 1) surface are investigated by means of density-functional theory. We take into account the clusters formed from three types of rotational conformers of cysteine; for each structure we investigate the protonated and unprotonated forms. Our investigations are based on three different geometrical models for the surface-adsorbate system, allowing us to describe the formation of new nucleation centers on the surface as well as the properties of long chains of cysteine molecules adsorbed on the Au(110)-(1 × 1) surface. We point out significant differences between the relaxed structures formed by each conformer as well as the specific physicochemical properties leading to formation of new nucleation centers compared with those of already formed large cysteine structures. In particular, we emphasize the role of the NH2 group of cysteine in these processes, by correlating our data with its relative position with respect to the gold surface. © 2013 American Chemical Society. Source

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