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Resendiz L.,Seccion de Estudios de Posgrado e Investigacion | Estrada M.,CINVESTAV | Cerdeira A.,CINVESTAV | Iniguez B.,Rovira i Virgili University | Deen M.J.,McMaster University
Organic Electronics: physics, materials, applications | Year: 2010

In this paper, we analyze the variation of the threshold voltage V T and carrier mobility μfet with the active layer thickness of polymer thin film transistors (PTFTs). The value of VT was observed to become more negative as the active layer thickness decrease, while mobility slightly increased. Simulations obtained for different active layer thickness were first validated with experimental data from measured devices with known active layer thickness. Then using the calibrated simulator, it was found that as the semiconductor thickness decreased, the charge per square units in the active layer changes, establishing the cause of both of these behaviors. © 2010 Elsevier B.V. All rights reserved.

Querejeta E.,Seccion de Estudios de Posgrado e Investigacion | Martinez-Romero B.,Hospital Psiquiatrico Fray Bernardino Alvarez Secretaria Of Salud | Miranda J.E.-G.,Seccion de Estudios de Posgrado e Investigacion | Delgado A.,Autonomous University of Chihuahua
Brain Research | Year: 2010

The modulation of the striato-pallidal pathway by presynaptic adenosine A2a and dopamine D2 receptors has gained attention in the study of Parkinson's disease. Here, we analyzed the effect of presynaptic A2a receptors in the spiking activity of globus pallidus (GP) neurons recorded during electrical stimulation of the striato-pallidal pathway, in both sham and ipsilaterally dopamine-denervated rats. We found that intrapallidal blockade of A2a by 100 pMol KF-17383 in sham and lesioned rats did not modify the spiking rate of GP neurons. Local infusion of 100 pMol CGS-21680, an A2a agonist, did not change the spiking rate in sham rats, whereas the same concentration of NMDA strongly increased the firing frequency of all neurons tested. Moreover, in sham rats, local blockade of A2a receptors by 100 pMol KF-17383 suppressed the inhibition evoked by activation of the striato-pallidal pathway, while in dopamine-denervated rats the same dose of KF-17383 did not modify the inhibition. Our results show that the contribution of A2a receptors to the spiking control of GP by the striato-pallidal pathway depends on the state of the dopaminergic system. © 2010 Elsevier B.V.

Perez-Cruz J.H.,University of Guadalajara | Chairez I.,UPIBI IPN | De Jesus Rubio J.,Seccion de Estudios de Posgrado e Investigacion | Pacheco J.,Seccion de Estudios de Posgrado e Investigacion
IET Control Theory and Applications | Year: 2014

In this study, a neuro-controller with adaptive deadzone compensation for a class of unknown SISO non-linear systems in a Brunovsky form with uncertain deadzone input is presented. Based on a proper smooth parameterisation of the deadzone, the unknown dynamics is identified by using a continuous time recurrent neural network whose weights are adjusted on-line by stable differential learning laws. On the basis of this neural model so obtained, a feedback linearisation controller is developed in order to follow a bounded reference trajectory specified. By means of Lyapunov analysis, the boundedness of all the closed-loop signals as well as the weights and deadzone parameter estimations is rigorously proven. Besides, the exponential convergence of the actual tracking error to a bounded zone is guaranteed. The effectiveness of this scheme is illustrated by a numerical simulation. © The Institution of Engineering and Technology 2014.

Trejo-Valdez M.,National Polytechnic Institute of Mexico | Torres-Martinez R.,Research Center en Ciencia Aplicada | Perea-Lopez N.,Laboratory for Nanoscience and Nanotechnology Research LINAN | Santiago-Jacinto P.,National Autonomous University of Mexico | Torres-Torres C.,Seccion de Estudios de Posgrado e Investigacion
Journal of Physical Chemistry C | Year: 2010

We measured the absorptive and refractive nonlinearities in Au nanoparticles when they are embedded in a TiO2 film and when they are suspended in ethanol. The morphology of the nanoparticles was estimated by using HRTEM microscopy. Different contributions related to electronic polarization and two-photon absorption were observed in the samples using a self-diffraction technique with pulses of 26 ps at 532 nm. Transmittance experiments were performed in order to confirm the mechanisms of optical absorption. The Au nanoparticles were grown by the photoreduction of TiO 2 sol-gel solutions which contain Au3+ ions. The thin films were prepared by using the dip coating technique with fresh UV exposed sol-gel solutions. We observed that when the sample does not present any important nonlinear absorption it is possible to enhance the participation of the nanoparticles in the optical Kerr response of the media. © 2010 American Chemical Society.

Cruz y Cruz S.,Seccion de Estudios de Posgrado e Investigacion | Rosas-Ortiz O.,CINVESTAV
International Journal of Theoretical Physics | Year: 2011

The Schrödinger equation for position-dependent mass singular oscillators is solved by means of the factorization method and point transformations. These systems share their spectrum with the conventional singular oscillator. Ladder operators are constructed to close the su(1,1) Lie algebra and the involved point transformations are shown to preserve the structure of the Barut-Girardello and Perelomov coherent states. © 2011 Springer Science+Business Media, LLC.

Velazquez-Roman J.A.,Seccion de estudios de posgrado e investigacion
Clinical and experimental hypertension (New York, N.Y. : 1993) | Year: 2011

Both gestation and diabetes mellitus (DM) are conditions associated with an increased participation of renin-angiotensin system (RAS) as well as with changes in the vascular response to angiotensin II (Ang II). We sought to establish the impact of gestational diabetes mellitus (GDM) on Ang II- induced vasoconstriction and its correlation with the expression of angiotensin II receptors (AT(1)R, AT(2) R). Female Wistar rats, virgin, or on day 3 after mating, received randomly streptozotocin (STZ) 60 mg/kgor saline ip.Streptozotocin-treated animals developed hyperglycemia (25.6 ± 1.42 mM). Ang II-induced vasoconstriction was evaluated on isolated aortas with (e+) and without (e-) endothelium and the protein expression of AT(1)R and AT(2)R was measured by western blot. Gestational diabetes mellitus significantly increased vasoconstriction with respect to all the other groups. Changes were observed only on e+ vessels. Interestingly, GDM moved AT(1)R: AT(2)R balance towards AT(1) R, while both pregnancy and diabetes towards AT(2)R expression. In conclusion, GDM increases the possibility of an hypertensive complication by an increased AT(1)R expression.

Rosas-Ortiz O.,CINVESTAV | Cruz S.C.Y.,Seccion de Estudios de Posgrado e Investigacion | Fernandez-Garcia N.,Seccion de Estudios de Posgrado e Investigacion
Journal of Physics: Conference Series | Year: 2012

The phase time of wave reflection from a one-dimensional semi-harmonic well includes a delay term which can be negative according to the incoming energy and the well parameters in a quantum scattering process. The model is a rectangular well which is embedded in an environment composed by a zero potential energy to its right and a harmonic-like potential to its left. © Published under licence by IOP Publishing Ltd.

Bermudez D.,CINVESTAV | Fernandez C. D.J.,CINVESTAV | Fernandez-Garcia N.,Seccion de Estudios de Posgrado e Investigacion
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2012

A Wronskian differential formula, useful for applying the confluent second-order SUSY transformations to arbitrary potentials, will be obtained. This expression involves a parametric derivative with respect to the factorization energy which, in many cases, is simpler for calculations than the previously found integral equation. This alternative mechanism will be applied to the free particle and the single-gap Lamé potential. © 2011 Elsevier B.V. All rights reserved.

Hernandez-Juarez J.R.,Comunicaciones y Electronica en la Seccion de Estudios de Posgrado e Investigacion | Ramirez-Garcia E.,Seccion de Estudios de Posgrado e Investigacion
CHILECON 2015 - 2015 IEEE Chilean Conference on Electrical, Electronics Engineering, Information and Communication Technologies, Proceedings of IEEE Chilecon 2015 | Year: 2015

In this paper we present the treatment of two fundamental concepts in different disciplines of engineering and physical sciences: Dimension and space. First, we use an intuitive and pragmatic treatment of both identities. After, we introduce the formal treatment for scalar and vector quantities explaining that dimension and space as concepts are implicitly included in the geometrical representation and algebraic expressions. Finally, we give the definition of both entities and how they can be assimilated and introduced to the students of engineering. © 2015 IEEE.

Perez-Cruz J.H.,University of Guadalajara | Ruiz-Velazquez E.,University of Guadalajara | De Jesus Rubio J.,Seccion de Estudios de Posgrado e Investigacion | De Alba-Padilla C.A.,University of Guadalajara
Mathematical Problems in Engineering | Year: 2012

In this study, the problem of controlling an unknown SISO nonlinear system in Brunovsky canonical form with unknown deadzone input in such a way that the system output follows a specified bounded reference trajectory is considered. Based on universal approximation property of the neural networks, two schemes are proposed to handle this problem. The first scheme utilizes a smooth adaptive inverse of the deadzone. By means of Lyapunov analyses, the exponential convergence of the tracking error to a bounded zone is proven. The second scheme considers the deadzone as a combination of a linear term and a disturbance-like term. Thus, the estimation of the deadzone inverse is not required. By using a Lyapunov-like analyses, the asymptotic converge of the tracking error to a bounded zone is demonstrated. Since this control strategy requires the knowledge of a bound for an uncertainty/disturbance term, a procedure to find such bound is provided. In both schemes, the boundedness of all closed-loop signals is guaranteed. A numerical experiment shows that a satisfactory performance can be obtained by using any of the two proposed controllers. © 2012 J. Humberto Pérez-Cruz et al.

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