Stress-induced Ageing of Lithium-Ion Batteries.

Lithium-ion batteries are well established for use in portable consumer products and are increasingly used in high power electro-mobility and photovoltaic storage applications. In hybrid and plug-in electric vehicles degradation and useful lifetime at standard operation conditions are critical parameters in addition to performance and safety. Here stress-induced ageing of commercially available high power battery cells of the type A123 AHR32113M1 Ultra-B, consisting of a LiFePO(4) cathode and a graphite anode have been investigated.

Helium focused ion beam fabricated plasmonic antennas with sub-5 nm gaps.

We demonstrate a reliable fabrication method to produce plasmonic dipole nanoantennas with gap values in the range of 3.5-20 nm. The method combines electron beam lithography to create gold nanorods and helium focused ion beam milling to cut the gaps.

Novel slanted incidence air-coupled ultrasound method for delamination assessment in individual bonding planes of structural multi-layered glued timber laminates.

Non-destructive assessment of delaminations in glued laminated timber structures is required during their full life cycle. A novel air-coupled ultrasound (ACU) method has been developed, which is able to separately detect delaminations in individual bonding planes of arbitrarily high and long laminated stacks and typically 200 mm wide. The 120 kHz ACU transmitter-receiver pair is positioned at two opposite lateral faces of the sample, with a small inclination with respect to the inspected bonding planes, so that an ultrasound beam is excited at a user-defined refraction angle within the sample, interacting with defects in a limited height portion of the stack.

Modeling and prediction of density distribution and microstructure in particleboards from acoustic properties by correlation of non-contact high-resolution pulsed air-coupled ultrasound and X-ray images.

Non-destructive density and microstructure quality control testing in particleboards (PBs) is necessary in production lines. A pulsed air-coupled ultrasound (ACU) high-resolution normal transmission system, together with a first wave tracking algorithm, were developed to image amplitude transmission G(p) and velocity c(p) distributions at 120kHz for PBs of specific nominal densities and five particle geometries, which were then correlated to X-ray in-plane density images ρ(s). Test PBs with a homogeneous vertical density profile were manufactured in a laboratory environment and conditioned in a standard climate (T=20°C, RH=65%) before the measurements.

Reduction of phase artifacts in differential phase contrast computed tomography.

X-ray differential phase contrast computed tomography (DPC CT) with a Talbot-Lau interferometer setup allows visualizing the three-dimensional distribution of the refractive index by measuring the shifts of an interference pattern due to phase variations of the X-ray beam. Unfortunately, severe reconstruction artifacts appear in the presence of differential phase wrapping and clipping. In this paper, we propose to use the attenuation contrast, which is obtained from the same measurement, for correcting the DPC signal.

Fully Metal-Coated Scanning Near-Field Optical Microscopy Probes with Spiral Corrugations for Superfocusing under Arbitrarily Oriented Linearly Polarised Excitation.

We study the effect of a spiral corrugation on the outer surface of a fully metal-coated scanning near-field optical microscopy (SNOM) probe using the finite element method. The introduction of a novel form of asymmetry, devoid of any preferential spatial direction and covering the whole angular range of the originally axisymmetric tip, allows attaining strong field localization for a linearly polarised mode with arbitrary orientation. Compared to previously proposed asymmetric structures which require linearly polarised excitation properly oriented with respect to the asymmetry, such a configuration enables significant simplification in mode injection.

Atomically flat single-crystalline gold nanostructures for plasmonic nanocircuitry.

Deep subwavelength integration of high-definition plasmonic nanostructures is of key importance in the development of future optical nanocircuitry for high-speed communication, quantum computation and lab-on-a-chip applications. To date, the experimental realization of proposed extended plasmonic networks consisting of multiple functional elements remains challenging, mainly because of the multi-crystallinity of commonly used thermally evaporated gold layers. This can produce structural imperfections in individual circuit elements that drastically reduce the yield of functional integrated nanocircuits.

Effects of asymmetric surface corrugations on fully metal-coated scanning near field optical microscopy tips.

We propose a new configuration for a fully metal coated scanning near field (SNOM) probe based on asymmetric corrugations in the metal coating. The variation in the metal surface induces coupling mechanisms leading to the creation of a localized hot spot under linearly polarized excitation. Field localization is an effect of paramount importance for resolution but cannot be achieved with standard axisymmetric fully metal-coated probes, unless a more cumbersome radially polarized excitation is used.

Measurement of the thermal conductivity of individual carbon nanotubes by the four-point three-omega method.

The thermal conductivity of individual multiwalled carbon nanotubes was measured by utilizing the four-point-probe third-harmonic method, based on the fact that the third harmonic amplitude and phase as a response to applied alternate current at fundamental frequency, omega, can be expressed in terms of thermal conductivity and diffusivity. To this end, a microfabricated device composed of four metal electrodes was modified to manufacture nanometer-sized wires by using a focused ion beam source. A carbon nanotube could then be suspended over a deep trench milled by the focused ion beam, preventing heat loss to the substrate.