Design of a micro-pattern structure for a three dimensionally macroporous Sn-Ni alloy anode with high areal capacity

A highly patterned porous Sn-Ni anode with various patterns was investigated as an anode for a lithium battery and showed much higher areal capacity than a conventional graphite electrode. This result proves the importance of a structured electrode for development of an electrode with higher performance.     

Fluorescence properties of 2-aryl substituted indoles

The fluorescence properties of 2-phenylindole, 2-naphthylindole and 2-anthracenylindole were investigated. 2-Anthracenylindole was newly synthesized by Suzuki-Miyaura's coupling. The fluorescence quantum yield of 2-phenylindole was the highest and the fluorescence emission maximum wavelength of 2-anthracenylindole was the longest. The ab initio quantum chemical calculation of the 2-anthracenylindole showed that the HOMO and LUMO of 2-anthracenylindole were localized in the anthracene moiety.     

Room-Temperature Silicon Nitrides Prepared with Very High Rates (>50 nm/s) in Atmospheric-Pressure Very High-Frequency Plasma

We have investigated the structure and stability of SiN _x films deposited with very high rates (>50 nm/s) in atmospheric-pressure (AP) He-based plasma excited by a 150 MHz very high-frequency (VHF) power using a cylindrical rotary electrode at room temperature. The SiN _x films are prepared on Si(001) substrates with varying VHF power density (P _VHF), H₂ concentration and source ratio (NH₃/SiH₄). Infrared absorption spectroscopy is used to analyze the bonding configurations in the films. The results show that increasing H₂ concentration under the supply of a moderately large P _VHF, together with the adjustment of NH₃/SiH₄ ratio, enables us to prepare SiN _x showing reasonable stability against a buffered hydrofluoric acid solution in spite of the very high deposition rate of 130 nm/s. The achievement of such a high-rate deposition at room temperature is primarily due to the significant enhancement of both gas-phase and surface-phase reactions in AP-VHF plasma.     

Kinetic studies of colloidal crystallization of thermo-sensitive gel spheres of poly(N-isopropylacrylamide)

Crystal growth rate coefficients, k of the colloidal crystallization of thermo-sensitive gel spheres of poly(N-isopropylacrylamide) were measured from the time-resolved reflection spectroscopy mainly by the inverted mixing method in the deionized state. Crystallization of colloidal silica spheres were also measured for comparison. The k values of gel and silica systems increased sharply as the sphere concentration and suspension temperature increased. The k values of gel system were insensitive to the degree of cross-linking in the range from 10 to 2?mol% of cross-linker against amount of the monomer in mole and decreased sharply when the degree of cross-linking decreased further to 0.5?%. The k values increased as gel size increased. The k values of gel systems at 20?°C were small and observed only at the very high sphere concentration in volume fraction, whereas those at 45?°C were high but smaller than those of silica systems. Induction time (t _i) after which crystallization starts, increased as the degree of cross-linking increased and/or the gel size decreased at any temperatures, when comparison was made at the same gel concentration. The t _i values at 45?°C were high and decreased sharply with increasing sphere concentration, whereas those at 20?°C were high only at the very high sphere concentrations. Significant difference in the k and t _i values between the soft gels and hard silica spheres was clarified. These kinetic results support that the electrical double layers play an important role for the gel crystallization in addition to the excluded volume of gel spheres. It is deduced further that the electrical double layers of the gel system form from the vague interfaces (between soft gel and water phases) compared with those of typical colloidal hard sphere system.     

Auslander algebras Of finite representation type

In this paper we give necessary and sufficient conditions for Auslander-Reiten quivers to be of finite representation type. If an algebra is standard this gives necessary and sufficient conditions for Auslander algebras to be of finite representation type.     

A local condition for k-contractible edges

An edge of a $k$-connected graph is said to be $k$-contractible if the contraction of the edge results in a $k$-connected graph. For a graph $G$ and a vertex $x$ of $G$, let $G\left[N_G\left(x\right)\right]$ be the subgraph induced by the neighborhood of $x$. We prove that if $G\left[N_G\left(x\right)\right]$ has less than $?\frac{k}{2}?$ edges for any vertex $x$ of a $k$-connected graph $G$, then $G$ has a $k$-contractible edge. We also show that the bound $?\frac{k}{2}?$ is sharp.     

Tris‐Heteroleptic Ruthenium–Dipyrrinate Chromophores in a Dye‐Sensitized Solar Cell

Two novel tris‐heteroleptic Ru–dipyrrinates were prepared and tested as sensitizers in the dye‐sensitized solar cell (DSSC). Under AM 1.5 sunlight, DSSCs employing these dyes achieved power conversion efficiencies (PCEs) of 3.4 and 2.2 %, substantially exceeding the value achieved previously with a bis‐heteroleptic dye (0.75 %). As shown by electrochemical measurements and DFT calculations, the improved PCEs stem from the synthetically tuned electronic structure, which affords more negative excited state redox potentials and favorable electron injection into the TiO₂ conduction band. Electron injection was quantified by nanosecond transient absorption spectroscopy, which revealed that the highest injection yield is achieved with the dye that acts as the strongest photoreductant.     

Preparation and properties of flexible free‐standing films via polyalkoxysiloxanes by acid‐catalyzed controlled hydrolytic polycondensation of tetraethoxysilane and tetramethoxysilane

Acid‐catalyzed controlled hydrolytic polycondensation of tetraethoxysilane (TEOS) and tetramethoxysilane (TMOS) provided polyalkoxysiloxanes PEOS and PMOS, with high molecular weight of 1100–12 000 or 2700–31 000, respectively. They were stable to self‐condensation, soluble in organic solvents, and especially characterized by high silica content of up to 62% (PEOS) and 72% (PMOS). Flexible and transparent free‐standing films with tensile strength of 1.6–5.2 MPa (PEOS) or 3.6–11.8 MPa (PMOS) were prepared by heating polyalkoxysilanes at 80°C for one to several days. They are also regarded to be a potential precursor for coatings and binders. Copyright © 2012 John Wiley & Sons, Ltd.