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Yu P.,Data Storage Institute Singapore
International Journal of Heat and Mass Transfer | Year: 2012

Detailed numerical simulations are performed for oxygen transfer around and within a circular scaffold for animal cell culture. The oxygen concentration distribution, minimum oxygen concentration within the scaffold and its corresponding location, as well as the Sherwood number are presented at different Darcy numbers, Reynolds numbers and Damkohler numbers. It is found that if the Reynolds number is increased from 1 to 30, the Sherwood number increases 1 time for a Darcy number of 5 × 10 -6 while 34 times for a Darcy number of 5 × 10 -4. The location of the minimum oxygen concentration is close to the centre of the scaffold when the Darcy number is smaller than about 5 × 10 -5 or the Reynolds number is smaller than about 1, especially for the Damkohler number larger than O(10). The present study may provide useful guidance on design of the bioreactor with scaffold as well as choosing optimal operating parameters. © 2012 Elsevier Ltd. All rights reserved. Source

Li G.,Data Storage Institute Singapore | Wen C.,Nanyang Technological University
IEEE Transactions on Signal Processing | Year: 2012

In this paper, we consider the parametric version of Wiener systems where both the linear and nonlinear parts are identified with clipped observations in the presence of internal and external noises. Also the static functions are allowed noninvertible. We propose a classification based support vector machine (SVM) and formulate the identification problem as a convex optimization. The solution to the optimization problem converges to the true parameters of the linear system if it is an finite-impulse-resposne (FIR) system, even though clipping reduces a great deal of information about the system characteristics. In identifying a Wiener system with a stable infinite-impulse-response (IIR) system, an FIR system is used to approximate it and the problem is converted to identifying the FIR system together with solving a set of nonlinear equations. This leads to biased estimates of parameters in the IIR system while the bias can be controlled by choosing the order of the approximated FIR system. © 2012 IEEE. Source

Ding W.,National University of Singapore | Luk'Yanchuk B.,Data Storage Institute Singapore | Qiu C.-W.,National University of Singapore
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

We report a distinguished mechanism of using two interaction-free (uncoupled) cavities to realize an all-optical silicon diode with an extremely high contrast ratio. In contrast to existing examples of all-optical diodes, our unidirectional transmission results from mimicking Fano resonance in a compact and finite silicon waveguide. A Fano spectrum with an arbitrary asymmetric factor, resonant center, and linewidth is explicitly designed with two symmetric resonances, which can be separately realized and tuned in an insightful manner by two cascaded uncoupled cavities. The field localizations are inherently asymmetric. We show that if these double asymmetries (Fano spectrum and field localization) are integrated and controlled, an ultrahigh-contrast-ratio silicon Fano diode is accomplished. This finding provides a promising avenue for achieving an extremely compact optical switch and incorporating Fano resonance in silicon photonics. © 2012 American Physical Society. Source

Miroshnichenko A.E.,Australian National University | Luk'Yanchuk B.,Data Storage Institute Singapore | Maier S.A.,Imperial College London | Kivshar Y.S.,Australian National University
ACS Nano | Year: 2012

Figure Persented: We propose a novel type of hybrid metal-dielectric structures composed of silicon nanoparticles and split-ring resonators for advanced control of optically induced magnetic response. We reveal that a hybrid "metamolecule" may exhibit a strong distance-dependent magnetic interaction that may flip the magnetization orientation and support "antiferromagnetic" ordering in a hybrid metamaterial created by a periodic lattice of such metamolecules. The propagation of magnetization waves in the hybrid structures opens new ways for manipulating artificial "antiferromagnetic" ordering at high frequencies. © 2011 American Chemical Society. Source

Luk'Yanchuk B.,Data Storage Institute Singapore | Zheludev N.I.,University of Southampton | Maier S.A.,Imperial College London | Halas N.J.,Rice University | And 4 more authors.
Nature Materials | Year: 2010

Since its discovery, the asymmetric Fano resonance has been a characteristic feature of interacting quantum systems. The shape of this resonance is distinctively different from that of conventional symmetric resonance curves. Recently, the Fano resonance has been found in plasmonic nanoparticles, photonic crystals, and electromagnetic metamaterials. The steep dispersion of the Fano resonance profile promises applications in sensors, lasing, switching, and nonlinear and slow-light devices. © 2010 Macmillan Publishers Limited. All rights reserved. Source

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