Comparison of dye solar cell counter electrodes based on different carbon nanostructures

Three characteristically different carbon nanomaterials were compared and analyzed as platinum-free counter electrodes for dye solar cells: 1) single-walled carbon nanotube (SWCNT) random network films on glass, 2) aligned multi-walled carbon nanotube (MWCNT) forest films on Inconel steel and quartz, and 3) pressed carbon nanoparticle composite films on indium tin oxide-polyethylene terephtalate plastic. Results from electrochemical impedance spectroscopy and electron microscopy were discussed in terms of the catalytic activity, conductivity, thickness, transparency and flexibility of the electrode films. The SWCNT films showed reasonable catalytic performance at similar series resistance compared to platinized fluorine doped tin oxide-coated glass. The MWCNTs had similar catalytic activity, but the electrochemical performance of the films was limited by their high porosity. Carbon nanoparticle films had the lowest charge transfer resistance resulting from a combination of high catalytic activity and dense packing of the material.     

Benefits of Partitioning in a Projection-based and Realizable Model-order Reduction Flow

Model-order reduction (MOR) is a typical approach to speed up the post-layout verification simulation step in circuit design. This paper studies the benefits of using circuit partitioning in a complete MOR flow. First, an efficient reduction algorithm package comprising of partitioning, reduction, and realization parts is presented. The reduction flow is then discussed using theoretical analysis and simulations from an array of 65-nm technology node interconnect circuits. It is shown that the reduction efficiency and computational costs quickly worsen with increased circuit size when using a direct projection-based MOR approach. In contrast, by using partitioning, the MOR can retain the scalability of the reduction problem, being computationally lighter and more efficient even with larger circuits. In addition, using partitioning may improve the robustness of the MOR flow in cases with circuits with many ports or sensitive verification simulations.     

Adaptive and cross-adaptive responses of persistent and non-persistent Listeria monocytogenes strains to disinfectants

Persistent and non-persistent Listeria monocytogenes strains were tested for initial resistance and adaptive and cross-adaptive responses towards two quaternary ammonium compounds, alkyl-benzyl-dimethyl ammonium chloride and n-alkyldimethyl ethylbenzyl ammonium chloride, one tertiary alkylamine, 1,3-propanediamine-N-(3-aminopropyl)N-dodecyl, sodium hypochlorite and potassium persulphate. The initial resistance of two persistent and two non-persistent L. monocytogenes strains was observed to differ. Both types of strains adapted after a 2-h sublethal exposure to the quaternary ammonium compounds and the tertiary alkylamine, the highest increase in the minimum inhibitory concentration (MIC) being 3-fold. Progressively increasing disinfecting concentrations at 10 and 37 degrees C resulted in adaptation of L. monocytogenes to all disinfectants except potassium sulphate. The highest observed increase in MIC was over 15-fold, from 0.63 to 10 microg/ml of n-alkyldimethyl ethylbenzyl ammonium chloride. All strains reached approximately similar MICs. Stability of the increased resistance was tested by measuring MICs every seventh day for 28 days. The increased resistance to sodium hypochlorite disappeared in 1 week, but the quaternary ammonium compounds and the tertiary alkylamine showed increased resistance for 28 days. These results suggest that cellular changes due to adaptive responses continue to have an effect on the resistance some time after the exposure. All disinfectants were shown to cause cross-adaptation of L. monocytogenes, the highest increase in MIC being almost 8-fold. The only agent that L. monocytogenes could not be shown to cross-adapt to was potassium persulphate which did, however, cause cross-adaptation to the other disinfectants. The mechanism behind these adaptive responses seemed to be non-specific as cross-adaptation was observed not only between related but also unrelated disinfectants. These findings suggest that sustaining high disinfectant effectiveness may be unsuccessful by rotation, even when using agents with different mechanisms of action.     

纳米TiO2薄膜厚度与不锈钢基体对染料敏化太阳能电池的影响

由于用金属做光阳极基体的染料敏化太阳能电池(DSCs)可以制作成柔性电池,成本低并且有广泛的用途,受到越来越多的关注.用导电玻璃和304不锈钢作为基体制作了DSCs,研究了纳米TiO2薄膜厚度和不锈钢基体对DSCs光电转换性能以及稳定性的影响.结果表明,TiO2薄膜厚度在20μm左右,玻璃DSCs具有较高的光电转化效率和稳定性.而不锈钢DSCs的稳定性较差,特别是不锈钢做光阳极基体的DSCs.