Academic Research Papers from the projects funded in Phase 1 of the Network
NRN141 - Self-Structuring of Granular material under Capillary Bulldozing
EPJ Web Conf.
An experimental observation of the structuring of a granular suspension under the progress of a gas/liquid meniscus in a narrow tube is reported here. The granular material is moved and compactifies as a growing accumulation front. The frictional interaction with the confining walls increases until the pore capillary entry pressure is reached. The gas then penetrates the clogged granular packing and a further accumulation front is formed at the far side of the plug. This cyclic process continues until the gas/liquid interface reaches the tube’s outlet, leaving a trail of plugs in the tube. Such 1D pattern formation belongs to a larger family of patterning dynamics observed in 2D Hele-Shaw geometry. The cylindrical geometry considered here provides an ideal case for a theoretical modelling for forced granular matter oscillating between a long frictional phase and a sudden viscous fluidization.
NRN147 - DSP-Enabled Reconfigurable and Transparent Spectral Converters for Converging Optical and Mobile Fronthaul/Backhaul Networks
Dynamically reconfigurable and transparent signal spectral conversion is expected to play a vital role in seamlessly integrating traditional metropolitan optical networks and mobile fronthaul/backhaul networks. In this paper, a simple digital signal processing (DSP)-enabled spectral converter is proposed and extensively investigated, for the first time, which just utilizes a single standard dual-parallel Mach-Zehnder modulator (DP-MZM) driven by SDN-controllable RF signals and DC bias currents. As an important thrust of the paper, optimum operating conditions of the proposed converter are analytically identified, statistically examined and experimentally verified.
NRN113 - Refractive Index Less than Two: Photonic Nanojets yesterday, today and tomorrow (invited)
Optical Materials Express
Materials with relatively small refractive indices (?<2 n<2 ), such as glass, quartz, polymers, some ceramics, etc., are the basic materials in most optical components (lenses, optical fibres, etc.). In this review, we present some of the phenomena and possible applications arising from the interaction of light with particles with a refractive index less than 2. The vast majority of the physics involved can be described with the help of the exact, analytical solution of Maxwell’s equations for spherical particles (so called Mie theory). We also discuss some other particle geometries (spheroidal, cubic, etc.) and different particle configurations (isolated or interacting) and draw an overview of the possible applications of such materials, in connection with field enhancement and super resolution nanoscopy.
NRN103 - Homogenisation of Porous Piezoelectric Material
This paper presents a homogenization study of porous piezoelectric materials through analytical and numerical analysis. Using two of the most well-known analytical methods for theoretical homogenization, the Mori–Tanaka and self-consistent schemes, the full set of material properties are obtained. These results are compared to two different theoretical bounds, the Halpin–Tsai and Hashin–Sthrikman bounds. A numerical model of a representative volume element is then developed using finite element analysis for different percentages of inclusions. Finally, the analytical and numerical results are compared and discussed; a good agreement between the analytical and numerical methods is shown.
NRN113 - Superlensing Microscope Objective Lens
Conventional microscope objective lenses are diffraction limited; they cannot resolve subdiffraction features of a size smaller than 250–300 nm under white lighting condition. New innovations are required to overcome this limitation. In this paper, we propose and demonstrate a new superlensing objective lens that possesses a resolution of 100 nm, which is a two-times resolution improvement over conventional objectives. This is accomplished by integrating a conventional microscope objective lens with a superlensing microsphere lens using a customized lens adaptor. The new objective lens was successfully demonstrated for label-free super-resolution imaging of 100 nm features in engineering and biological samples, including a Blu-ray disk sample and adenoviruses. Our work opens a new door to develop a generic optical superlens, which may transform the field of optical microscopy and imaging.