Synthesis and oxygen permeation properties of 75 mol% Ce0.75Nd0.25O1.875–25 mol% Nd1.8Ce0.2CuO4 composite

An oxygen-permeable composite constituted to oxide ionic conductor phase (Ce_0.75Nd_0.25O_1.875) and oxide electronic conductor phase (Nd_1.8Ce_0.2CuO₄) was prepared using the acetate pyrolysis method. Based on electrical conductivity measurements, total electrical conductivity of 75 mol% Ce_0.75Nd_0.25O_1.875–25 mol% Nd_1.8Ce_0.2CuO₄ composite material was governed by the electronic conduction paths. With respect to the oxygen permeation properties, the results showed that oxygen permeation properties were unexplainable by a simple composite rule using the electrical transport properties of the bulk Ce_0.75Nd_0.25O_1.875 and the bulk Nd_1.8Ce_0.2CuO₄.     

Characterization of positional and anomeric isomers of methyl 2-O- and 3-O-sulfo-D-glucopyranosiduronic acids and methyl 2-O- and 3-O-sulfo-D-glucopyranosides by secondary ion mass spectrometry

Secondary ion mass spectrometry (SIMS) of anomeric pairs of methyl 2-O- and 3-O-sulfo-D -glucopyranosiduronic acids and methyl 2-O- and 3-O-sulfo-D -glucopyranosides show the deprotonated molecule in the negative-ion mode and ammoniated and sodiated molecules in the positive-ion mode. The four isomers were distinguished from each other by linked scanning at constant B/E in negative- and positive-ion SIMS, which gave information characteristic of the position of the sulfate group and even the configuration of the anomeric methoxy group. The main fragmentation processes correspond to the loss of methanol and the elimination of SO₃.     

The Effect of Exposure Duration on Stereopsis and Its Dependency on Spatial Frequency

To investigate the effect of exposure duration on stereopsis and its spatial frequency dependency, we measured disparity threshold for the depth discrimination varying stimulus exposure duration between 0.05 and 2 s for three spatial frequencies (0.23, 0.94 and 3.75 c/deg). The results showed that disparity threshold decreased with increase in exposure duration up to a certain duration, beyond which it was approximately constant (the duration is called critical duration). The critical duration was about 150 ms for gratings with low and middle spatial frequencies (0.23 and 0.94 c/deg) while the duration was about 750 ms for gratings with high spatial frequency (3.75 c/deg). This suggests that temporal integration property varies dependently on stimulus spatial frequency. We also attempted to relate the spatial frequency dependency of the temporal integration property to the differences in temporal frequency tuning to different spatial frequency stimuli.     

Semi-Classical Analysis for Hartree Equations in Some Supercritical Cases

We study the semi-classical limit of the Hartree equation, which has focusing at a point. There exists a critical index indicating nonlinear effect around the caustic, and it is known that the influence by the nonlinearity is negligible in subcritical case (called linear caustic case), and that it is not in critical case (nonlinear caustic case). We give the asymptotic behavior beyond caustic in some supercritical cases which give rise to very strong nonlinear effect. Submitted: August 25, 2006. Accepted: December 11, 2006.     

Minimal cocycles with the scaling property and substitutions

‘Fractal’ functions are formulated as a minimal cocycle on a topological dynamics which admits nontrivial scaling transformations. In this paper, it is proved that if in addition it admits a continuous family of scaling transformations, then itscapacity is not ino(N ²). We define minimal cocycles with nontrivial scaling transformations coming from substitutions on a finite alphabet which are proved to have capacityO(N), so that they admit only a discrete family of scaling transformations. We also construct one which has capacityO(N ²) and admit a continuous family of scaling transformations. Supported by C.N.R.S.(U.R.A 225); Partially supported by the Japan Society for the Promotion of Science.     

Temperature-disturbance free magnetic field sensor based on double fiber optic polarimetry

A double fiber-optic Mach-Zehnder interferometer for sensing magnetic fields is devised using two polarization maintaining single-mode fibers. This sensor achieves not only highly sensitive performance but also excellent immunity from temperature disturbance. The sensitivity attains 243 deg/mT (mT=10^-3N/A) for the sensing part of the 5 cm long fiber.     

Synthesis of TiC-C fiber from titanium isopropoxide treated phenolic resin fiber

Precursor fibers for titanium carbide-carbon fibers were synthesized by reacting phenolic resin fibers with titanium isopropoxide (TIP). In this system, titanium oxide gel coated fiber was prepared by hydrolyzing TIP infiltrated resin fiber. The precursor fibers obtained after the hydrolysis were converted into titanium oxide-carbon fibers (TiO₂-C fibers) by pyrolysis at 1273 K. The TiO₂-C fibers were converted into titanium carbide-carbon fibers (TiC-C fibers) by heat treatment at 1373–1973 K. The mechanisms of the conversion from TiO₂-C fibers to TiC-C fibers were characterized by TGA.     

Cis and trans 4,8-dimethyl-6-phenyl-5,6,7,8-tetra-hydro-4H-1,3,6-oxadiazocin-2-ones: Conformational studies and configurational assignments by NMR

The reaction of N-(2-aminopropyl)-N-(2-hydroxypropyl)aniline with phosgene afforded cis and trans isomers of 4,8-dimethyl-6-phenyl-5,6,7,8-tetrahydro-4H-1,3,6-oxadiazocin-2-one. On the basis of ASIS data and Eu-shift difference, the title compounds are found to exist as boat-chair conformation in which the carbonyl carbon resides at the BC-2 position on the molecular plane.