Planar symmetry incompatibility in Ru-Sn-Zn pseudo-decagonal approximants composed of novel pentagonal antiprisms

Two new ternary compounds in the Ru-Sn-Zn system were synthesized by conventional high-temperature reactions, and their crystal structures were analyzed by means of the single crystal X-ray diffraction: Ru(2)Sn(2)Zn(3) (orthorhombic, Pnma, Pearson symbol oP28, a = 8.2219(16), b = 4.1925(8), c = 13.625(3) ?, V = 469.66(16) ?(3), Z = 4) and Ru(4.15)Sn(4.96)Zn(5.85) (orthorhombic, Pnma, Pearson symbol oP60-δ, a = 8.3394(17), b = 4.2914(9), c = 28.864(6) ?, V = 1032.98(40) ?(3), Z = 4). With the increase in the Sn content, the half-decagon structure unit with a triangle center in Ru(2)Sn(2)Zn(3) grows up to a symmetry incompatible decagonal unit with a central triangle in the common plane in Ru(4.15)Sn(4.96)Zn(5.85). Both structures can be described by hexagonal arrays of Sn-centered novel pentagonal antiprisms. In light of their pseudodecagonal diffraction in the h0l section and point group mmm, both phases are considered as new quasicrystal approximants in the Ru-Zn-Sn ternary system. The temperature dependences of the electrical resistivity for both compounds exhibit metallic behavior, but their Seebeck coefficients are of opposite sign.     

Bulk heterojunction organic photovoltaic cell fabricated by the electrospray deposition method using mixed organic solvent

A high‐efficiency bulk heterojunction organic photovoltaic cell (OPV) was achieved by the electrospray deposition method. The surface roughness of the P3HT:PCBM thin film can be reduced using the mixed solvent consisting of o‐dichlorobenzene (o‐DCB) and acetone. The effect of acetone concentration is related to its dielectric constant. Under an optimized concentration of acetone in o‐DCB (20 vol%), the P3HT/PCBM active layer with a smooth surface can be formed, and the power conversion efficiency of the OPV was 1.9%.

     

Hydrogen sensor based on oxide proton conductors and its application to metallurgical engineering

Galvanic cell-type hydrogen sensor for high temperature use is now available thanks to the discovery of oxide-type proton conducting solid electrolyte such as acceptor-doped perovskite-type oxides. In order to develop the practically functional hydrogen sensor based on these electrolytes, the electrochemical properties of these oxides should be understood as a function of hydrogen and oxygen potentials at the temperature range where the sensor is to be used. In this review, the properties of indium-doped calcium zirconate (represented by the composition CaZr_0.9In_0.1O_3–δ) known as, among these oxides, the most chemically stable and mechanically strong were explained briefly on the basis of the thermodynamics of the crystal imperfections. Then the structure of hydrogen sensor for molten aluminum and that for molten copper, which were designed to make the best use of the properties of the electrolyte for the respective process conditions, were shown. Lastly, the performance of these sensors examined in the laboratory scale and the practical industrial conditions was overviewed. Paper presented at the 9th EuroConference on Science and Technology of Ionics, Rhodes, Greece, Sept. 15 – 21, 2003.     

Slow light in coupled-resonator-induced transparency

We performed optical pulse propagation experiments in a system in which two ultrahigh-Q silica microspheres of different diameters were coupled in tandem to a fiber taper to yield coupled-resonator-induced transparency. Nearly Gaussian-shaped optical pulses propagated with a large positive delay of 8.5 ns through a transparent frequency window, without significant attenuation, amplification, or pulse deformation, demonstrating classical analogy of the extremely slow light obtained with electromagnetically induced transparency.     

Pedestal suppression of ultrashort pulses by using a birefringent nonlinear polarization rotation mirror

A new scheme for a birefringent nonlinear polarization rotation mirror is proposed for pedestal suppression of ultrashort pulses. Environmentally stable and precisely controllable operation is demonstrated. The main pulse and pedestal components are separated and picked out from the different ports. By use of the soliton effect and nonlinear polarization rotation, almost transform-limited pedestal-free 318 and 143 fs ultrashort pulses with peak powers of 0.9 and 1.7 kW are successfully generated. The maximum pedestal-suppression ratio is 24 dB, and the pick-out efficiency is up to 46% including coupling loss. The characteristics are analyzed both experimentally and numerically.     

Effects of Substituents on the Size of Water-Dispersible Phthalocyanine Colloids Synthesized by Reprecipitation

Phthalocyanine derivatives have become very well-known compounds because of their optical, electrical, and magnetic properties. We studied water-dispersible phthalocyanine colloids synthesized using a conventional reprecipitation method. The average phthalocyanine colloid diameter was closely related to the central metal and the peripheral phthalocyanine substituent. The average 4-phenylsulfonylphthalocyanine colloid diameter was much lower than that of 4-phenylsulfinylphthalocyanine because of the larger molecular size of the phthalocyanine macrocycle with sulfonyl substituent. Ni-phthalocyanine with sulphonyl substituent was found to have the lowest diameter of 28.0 nm.     

Characteristics of Guided Acoustic Wave Brillouin Scattering in Polarization Maintaining Fibers

Characteristics of guided acoustic wave Brillouin scattering in polarization maintaining fibers are investigated theoretically and experimentally. Spectra of polarized and depolarized scattering are measured for two different types of polarization maintaining fibers: the PANDA (polarization maintaining and absorption reducing) fibers and the elliptical-jacket fibers. Calculated results are in agreement with the experimental ones in the low frequency region.     

Reconstruction of the Gastric Surface Structure Using a Monocular CCD Endoscope

The object’s surface structure can be obtained from an image sequence taken through a conventional CCD endoscope. This paper reports clinical experimental results of the method. The accuracy of the estimation is studied and a method to estimate the reliability of the reconstructed shape is also described.