Stability and activity controls of Cu nanoparticles for high-performance solid oxide fuel cells

Cu-based electrodes could advance solid oxide fuel cells (SOFC) technology due to good electric conductivity and relatively high electrochemical activity among transition metals. However, one of the main challenges for designing anode materials is thermal stability in SOFC operation condition. Herein, a promising anode material decorated with Cu nanoparticles (NPs) was synthesized via in-situ exsolution from La0.43Sr0.37Cu0.12Ti0.88O3-δ (LSCuT) perovskite. Compared to infiltration process, Cu NPs prepared by in-situ exsolution displayed homogeneous nano size distribution on the substrate and excellent thermal stability at 600 °C in H2 atmosphere, for ∼50 h. In addition, we employed electrochemical reduction (ER) at 2.3 V for a few seconds to demonstrate that NPs can be rapidly grown, and the substrate reduced. A single cell with LSCuT anode (10 μm)||ScSZ electrolyte (90 μm) ||LSM-ScSZ cathode (20 μm) exhibits maximum power density of 1.38 Wcm−2 at 900 °C under wet H2. The present study provides possibility of a broad application of thermally stable Cu-based electrodes

Shape-shifting nanoparticles on a perovskite oxide for highly stable and active heterogeneous catalysis

Controlling the geometric shape of nano-catalysts plays a key role in maximizing unique properties of the materials. Although shape control of nanoparticles is well known by various preparation methods, still there is no clear case for exsolution. Here we show that the shape of embedded Ni nanoparticles can be changed on exsolution process, by controlling reduction temperature and time. To elucidate and generalize the shape-shifting, we develop a model which describes the equilibrium shape of nanoparticles on support thermodynamically. Our results suggest that there is a thermodynamic driving force for the exsolved nanoparticle to be stabilized into faceted shape with low surface/interface energy, during the particle growth. Through catalytic activity testing, the improved durability of shape-shifted Ni catalysts is confirmed on dry-reforming condition over 390 h, resulting from enhanced interface stability and cocking resistance. This provides theoretical and experimental framework for the shape control of exsolved particle on oxide support, but also for the design of unique catalyst with high stability and reactivity

Spinal Cord Stimulation for Refractory Angina Pectoris -A Case Report-

Refractory angina pectoris is defined as angina refractory to optimal medical treatment and standard coronary revascularization procedures. Despite recent therapeutic advances, patients with refractory angina pectoris are not adequately treated. Spinal cord stimulation is a minimally invasive and reversible technique which utilizes electrical neuromodulation by means of an electrode implanted in the epidural space. It has been reported to be an effective and safe treatment for refractory angina pectoris. We report a case of spinal cord stimulation which has effectively relieved chest pain due to coronary artery disease in a 40-year-old man. This is the first report of spinal cord stimulation for treatment of refractory angina pectoris in South Korea

The Safety and efficacy of a new self-expandable intratracheal nitinol stent for the tracheal collapse in dogs

To evaluate the potential utility of a self-expandable intratracheal nitinol stent with flared ends for the treatment of tracheal collapse in dogs, endotracheal stenting therapy was performed under fluoroscopic guidance in four dogs with severe tracheal collapse. During the 4 to 7 month follow-up, after stent implantation, clinical signs, including dyspnea and respiratory distress, dramatically improved in all dogs. The radiographs showed that the implanted stents improved the tracheal collapse, and there were no side effects such as collapse, shortening or migration of the stents. In conclusion, the self-expandable intratracheal nitinol stents provided adequate stability to the trachea and were effective for attenuating the clinical signs associated with severe tracheal collapse

Characteristics of gate-all-around silicon nanowire field effect transistors with asymmetric channel width and source/drain doping concentration

We performed 3D simulations to demonstrate structural effects in sub-20 nm gate-all-around silicon nanowire field effect transistors having asymmetric channel width along the channel direction. We analyzed the differences in the electrical and physical properties for various slopes of the channel width in asymmetric silicon nanowire field effect transistors (SNWFETs) and compared them to symmetrical SNWFETs with uniform channel width. In the same manner, the effects of the individual doping concentration at the source and drain also have been investigated. For various structural conditions, the current and switching characteristics are seriously affected. The differences attributed to the doping levels and geometric conditions are due to the electric field and electron density profile. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4745858]ope

Recent Progress on Polymeric Binders for Silicon Anodes in Lithium-Ion Batteries

Advanced polymeric binders with unique functions such as improvements in the electronic conduction network, mechanical adhesion, and mechanical durability during cycling have recently gained an increasing amount of attention as a promising means of creating high-performance silicon (Si) anodes in lithium-ion batteries with high energy density levels. In this review, we describe the key challenges of Si anodes, particularly highlighting the recent progress in the area of polymeric binders for Si anodes in cellsopen