Superhydrophobic carbon nanotube electrode produces a near-symmetrical alternating current from photosynthetic protein-based photoelectrochemical cells

The construction of protein-based photoelectrochemical cells that produce a variety of alternating currents in response to discontinuous illumination is reported. The photovoltaic component is a protein complex from the purple photosynthetic bacterium Rhodobacter sphaeroides which catalyses photochemical charge separation with a high quantum yield. Photoelectrochemical cells formed from this protein, a mobile redox mediator and a counter electrode formed from cobalt disilicide, titanium nitride, platinum, or multi-walled carbon nanotubes (MWCNT) generate a direct current during continuous illumination and an alternating current with different characteristics during discontinuous illumination. In particular, the use of superhydrophobic MWCNT as the back electrode results in a near symmetrical forward and reverse current upon light on and light off, respectively. The symmetry of the AC output of these cells is correlated with the wettability of the counter electrode. Potential applications of a hybrid biological/synthetic solar cell capable of generating an approximately symmetrical alternating current are discussed. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The use of non-dimensional parameters to study stress in lithiumion battery electrode storage particles

Mechanical degradation is thought to be one of the causes of capacity fade within Lithium-Ion batteries. In this work we develop a coupled stress-diffusion model for idealized spherical storage particles, which is analogous to the development of thermal strains. We then non-dimensionalize the model and identify three important parameters that control the development of stress within these particles. We can therefore use a wide number of values for these parameters to make predictions about the stress responses of different materials. The maximum stress developed within the particle for different values of these parameters are plotted as stress maps. A two dimensional model of a battery was then developed, in order to study the effect of particle morphology. Copyright © 2012 by ASME.

Radio over free space optical link using a directly modulated two-electrode high power tapered laser

The analog modulation performance of a high-power two-electrode tapered laser is investigated. A 25dB dynamic range for 2.4GHz 802.11g signals is achieved with a 26dB loss budget, showing a >1km free space range is possible. © 2010 Optical Society of America.

Gigabit/s modulation of twin-electrode high-brightness tapered laser with high modulation efficiency

Simultaneous high modulation speed and high modulation efficiency operation of a two-electrode tapered laser is reported. 1Gb/s direct data modulation is achieved with 68mA applied current swing for a 0.95W output optical modulation amplitude. © 2009 Optical Society of America.

Biofunctionalization of PET/SiO2 surfaces for single molecule experiments and medical applications

PET/SiO2 layers were chemically modified to maintain immobilization of functional single molecules. GFP molecules provide an ideal system due to their stability and intrinsic fluorescence. GFP in vivo biotinylated within its NH2-terminal region and attached on the substrate via the biotinstreptavidin bond was further investigated with confocal microscopy, atomic force microscopy (AFM) and spectroscopic ellipsometry (SE). AFM revealed monolayered donut-like structures representing assemblies of biotinstreptavidinbiotinGFP immobilized onto PET/SiO2 surfaces via mPEG. In particular, regions with an approximate height of 12 nm, which approaches the molecular dimensions of the above complex given by molecular modeling, could be detected. The dimensions of the donut-like structures suggest a close-to-each-other positioning of the GFP molecules - which, however, retain their functionality, as evidenced by confocal microscopy. © 2011 World Scientific Publishing Company.

An analysis of electrode patterns in capacitive touch screen panels

In the design of capacitive touch-screen panels, electrodes are patterned to improve touch sensitivity. In this paper, we analyze the relationship between electrode patterns and touch sensitivity. An approach is presented where simulations are used to measure the sensitivity of touch-screen panels based on capacitance changes for various electrode patterns. Touch sensitivity increases when the touch object is positioned in close proximity to fringing electric fields generated by the patterned electrodes. Three new electrode patterns are proposed to maximize field fringing in order to increase touch sensitivity by purely electrode patterning means. Simulations showed an increased touch sensitivity of up to 5.4%, as compared with the more conventional interlocking diamonds pattern. Here, we also report empirical findings for fabricated touch-screen panels. © 2005-2012 IEEE.