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Western University

Series

2017

Articles 1 - 7 of 7

Full-Text Articles in Physics

Photonic Band Structure Of Diamond Colloidal Crystals In A Cholesteric Liquid Crystal, Setarehalsadat Changizrezaei, Colin Denniston Sep 2017

Photonic Band Structure Of Diamond Colloidal Crystals In A Cholesteric Liquid Crystal, Setarehalsadat Changizrezaei, Colin Denniston

Physics and Astronomy Publications

In this paper, we demonstrate the presence of a photonic band gap for a diamond lattice structure made of particles with normal anchoring inside a cholesteric liquid crystal. As is typical for liquid crystals (LCs), there is considerable contrast between the dielectric constant parallel ε∥ and perpendicular ε⊥ to the director, with ε∥/ε⊥∼4 here. It is shown that the size of the photonic band gap is directly related to the size of colloidal particles and the contrast between the dielectric constant in the particles and the extreme values of ε in the LC medium (one needs either ε in the …

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Zr-Doped Tio2 As A Thermostabilizer In Plasmon-Enhanced Dye-Sensitized Solar Cells, Anastasia Pasche, Bernd Grohe, Silvia Mittler, Paul A. Charpentier Sep 2017

Zr-Doped Tio2 As A Thermostabilizer In Plasmon-Enhanced Dye-Sensitized Solar Cells, Anastasia Pasche, Bernd Grohe, Silvia Mittler, Paul A. Charpentier

Physics and Astronomy Publications

Harvesting solar energy is a promising solution toward meeting the world’s evergrowing energy demand. Dye-sensitized solar cells (DSSCs) are hybrid organic–inorganic solar cells with tremendous potential for commercial application, but they are plagued by in efficiency due to their poor sunlight absorption. Plasmonic silver nanoparticles (AgNPs) have been shown to enhance the absorptive properties of DSSCs, but their plasmonic resonance can cause thermal damage resulting in cell deterioration. Hence, the influence of Zr-doped TiO2 on the efficiency of plasmon-enhanced DSSCs was studied, showing that 5 mol.% Zr-doping of the photoactive TiO2 material can improve the photovoltaic performance of DSSCs by …

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Vacuum Birefringence, The Photon Anomalous Magnetic Moment And The Neutron Star Rx J1856.5−3754, Sree Ram Valluri, J.W. Mielniczuk, Farrukh Chishtie, D. Lamm, S. Auddy Aug 2017

Vacuum Birefringence, The Photon Anomalous Magnetic Moment And The Neutron Star Rx J1856.5−3754, Sree Ram Valluri, J.W. Mielniczuk, Farrukh Chishtie, D. Lamm, S. Auddy

Physics and Astronomy Publications

We analyse the spectrum of the Hamiltonian of a photon propagating in a strong magnetic field B ∼ Bcr, where Bcr=m2e≃4.4×1013" role="presentation">Bcr=m2e≃4.4×1013 G is the Schwinger critical field. We show that the anomalous magnetic moment of a photon in the one-loop approximation is a non-decreasing function of the magnetic field B in the range 0 ≤ B ≤ 30 Bcr. We provide a numerical representation of the expression for the anomalous magnetic moment in terms of special functions. We find that the anomalous magnetic moment μγ of a photon for B = 30 B …

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A Vision For Canadian Space Exploration, Ilaria Caiazzo, Sarah C. Gallagher, Jeremy Heyl Aug 2017

A Vision For Canadian Space Exploration, Ilaria Caiazzo, Sarah C. Gallagher, Jeremy Heyl

Physics and Astronomy Publications

We propose a sustained and balanced program in space exploration to fuel innovation in the space sector, support Canada's world-leading space researchers, inspire the next generation of scientists and innovators, and create thousands of highly skilled, well-paying jobs for Canadians. During the next decade we recommend a total investment of approximately $1B, increasing to $1.3B in each decade that follows, including a regular flagship mission that Canada would lead and a constellation of smaller missions, either led by Canada or in collaboration with international partners.

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Heterogeneous Colloidal Particles Immersed In A Liquid Crystal, Setarehalsadat Changizrezaei, Colin Denniston May 2017

Heterogeneous Colloidal Particles Immersed In A Liquid Crystal, Setarehalsadat Changizrezaei, Colin Denniston

Physics and Astronomy Publications

In this paper, we explore anisotropic interactions between particles with heterogeneous boundary conditions inside both nematic and cholesteric liquid crystals. The results show that when particles are put at different distances and angles with respect to each other, new types of defect structures are produced, depending on the relative distances and directions. In a cholesteric liquid crystal, the value of the pitch affects the defect structures and induced forces. Moreover, it was observed that it is energetically favorable for the particles to remain in a plane parallel to the far-field director in a nematic liquid crystal, while for particles immersed …

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Tutorial: The Quantum Finite Square Well And The Lambert W Function, Sree Ram Valluri, Ken Roberts Feb 2017

Tutorial: The Quantum Finite Square Well And The Lambert W Function, Sree Ram Valluri, Ken Roberts

Physics and Astronomy Publications

We present a solution of the quantum mechanics problem of the allowable energy levels of a bound particle in a one-dimensional finite square well. The method is a geometric-analytic technique utilizing the conformal mapping w -> z = we(w) between two complex domains. The solution of the finite square well problem can be seen to be described by the images of simple geometric shapes, lines, and circles, under this map and its inverse image. The technique can also be described using the Lambert W function. One can work in either of the complex domains, thereby obtaining additional insight into the …

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Deconstructing A Galaxy: Colour Distributions Of Point Sources In Messier 83, A. K. Kiar, P. Barmby, A. Hidalgo Jan 2017

Deconstructing A Galaxy: Colour Distributions Of Point Sources In Messier 83, A. K. Kiar, P. Barmby, A. Hidalgo

Physics and Astronomy Publications

What do we see when we look at a nearby, well-resolved galaxy? Thousands of individual sources are detected in multiband imaging observations of even a fraction of a nearby galaxy, and characterizing those sources is a complex process. This work analyses a ten-band photometric catalogue of nearly 70 000 point sources in a 7.3 square arcmin region of the nearby spiral galaxy Messier 83, made as part of the Early Release Science programme with the Hubble Space Telescope'sWide Field Camera 3. Colour distributions were measured for both broad-band and broad-and-narrow-band colours; colours made from broad-bands with large wavelength differences generally …

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