Electrical and Electronic Engineering - Research Publications

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    Minimum phase properties for input nonaffine nonlinear systems
    Nesic, D ; Skafidas, E ; Mareels, IMY ; Evans, RJ (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 1999-04-01)
    For input nonaffine nonlinear control systems, the minimum phase property of the system in general depends on the control law. Switching or discontinuous controllers may offer advantages in this context. In particular, there may not exist a continuous control law which would keep the output identically equal to zero and for which the zero output constrained dynamics are locally stable, whereas a discontinuous controller which achieves this exists. For single-input/single-output input nonaffine nonlinear systems we give sufficient conditions for existence and present a method for the design of discontinuous switching controllers which yield locally stable zero dynamics.
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    A Silk Fibroin Bio-Transient Solution Processable Memristor
    Yong, J ; Hassan, B ; Liang, Y ; Ganesan, K ; Rajasekharan, R ; Evans, R ; Egan, G ; Kavehei, O ; Li, J ; Chana, G ; Nasr, B ; Skafidas, E (NATURE PUBLISHING GROUP, 2017-11-07)
    Today's electronic devices are fabricated using highly toxic materials and processes which limits their applications in environmental sensing applications and mandates complex encapsulation methods in biological and medical applications. This paper proposes a fully resorbable high density bio-compatible and environmentally friendly solution processable memristive crossbar arrays using silk fibroin protein which demonstrated bipolar resistive switching ratio of 104 and possesses programmable device lifetime characteristics before the device gracefully bio-degrades, minimizing impact to environment or to the implanted host. Lactate dehydrogenase assays revealed no cytotoxicity on direct exposure to the fabricated device and support their environmentally friendly and biocompatible claims. Moreover, the correlation between the oxidation state of the cations and their tendency in forming conductive filaments with respect to different active electrode materials has been investigated. The experimental results and the numerical model based on electro-thermal effect shows a tight correspondence in predicting the memristive switching process with various combinations of electrodes which provides insight into the morphological changes of conductive filaments in the silk fibroin films.
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    A tight binding and (k)over-right-arrow . (p)over-right-arrow study of monolayer stanene
    Jiang, L ; Marconcini, P ; Hossian, MS ; Qiu, W ; Evans, R ; Macucci, M ; Skafidas, E (NATURE RESEARCH, 2017-09-21)
    Stanene is a single layer of tin atoms which has been discovered as an emerging material for quantum spin Hall related applications. In this paper, we present an accurate tight-binding model for single layer stanene near the Fermi level. We parameterized the onsite and hopping energies for the nearest, second nearest, and third nearest neighbor tight-binding method, both without and with spin orbital coupling. We derived the analytical solution for the [Formula: see text]and [Formula: see text] points and numerically investigated the buckling effect on the material electronic properties. In these points of the reciprocal space, we also discuss a corresponding [Formula: see text] description, obtaining the value of the [Formula: see text] parameters both analytically from the tight-binding ones, and numerically, fitting the ab-initio dispersion relations. Our models provide a foundation for large scale atomistic device transport calculations.
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    Environmentally friendly power generator based on moving liquid dielectric and double layer effect
    Huynh, DH ; Nguyen, TC ; Nguyen, PD ; Abeyrathne, CD ; Hossain, MS ; Evans, R ; Skafidas, E (NATURE PUBLISHING GROUP, 2016-06-03)
    An electrostatic power generator converts mechanical energy to electrical energy by utilising the principle of variable capacitance. This change in capacitance is usually achieved by varying the gap or overlap between two parallel metallic plates. This paper proposes a novel electrostatic micro power generator where the change in capacitance is achieved by the movement of an aqueous solution of NaCl. A significant change in capacitance is achieved due to the higher than air dielectric constant of water and the Helmholtz double layer capacitor formed by ion separation at the electrode interfaces. The proposed device has significant advantages over traditional electrostatic devices which include low bias voltage and low mechanical frequency of operation. This is critical if the proposed device is to have utility in harvesting power from the environment. A figure of merit exceeding 10000(10(8)μW)/(mm(2)HzV(2)) which is two orders of magnitude greater than previous devices, is demonstrated for a prototype operating at a bias voltage of 1.2 V and a droplet frequency of 6 Hz. Concepts are presented for large scale power harvesting.
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    Capacity and Data Rate for Millimeter Wavelength Systems in a Short Range Package Radio Transceiver
    Liu, C ; Skafidas, E ; Evans, RJ (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2010-03-01)
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    Design of 60 GHz millimetre-wave bandpass filter on bulk CMOS
    Yang, B ; Skafidas, E ; Evans, RJ (INST ENGINEERING TECHNOLOGY-IET, 2009-09-01)
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    Characterization of the 60 GHz wireless desktop channel
    Liu, C ; Skafidas, E ; Evans, RJ (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2007-07-01)