Magnetic properties of CoFeRu alloys in the f.c.c. and h.c.p. phases

Measurements have been made of the magnetization, the Fe⁵⁷ Mössbauer effect, and the crystal structures of Co-rich CoFeRu alloys. The alloys with f.c.c. structure behave in a typical ferromagnetic way, while those with h.c.p. structure show non-saturation of the magnetization in magnetic fields as high as 80 kG, and they show relatively small magnetic moments per atom and a broad single Mössbauer absorption.     

Cyclotron resonance in lead—II: Anisotropy,line shape,relaxation time and identification of the orbits

Through experimentation and analysis of the cyclotron resonance, the [110] arm in the electron Fermi surface of lead has been found to be a corrugated cylinder having different shapes of longitudinal cross section cut by various planes including the axis of the arm. The resonance amplitude of the orbit ζ on the [110] arm is also dependent on the crystallographic differences of the surfaces, even for the same orientation of the magnetic field. The best fitting of the theoretical overall line shape to the observed one of the orbit ζ has been obtained by considering the decrease of relaxation time for higher indices of harmonic resonance. The second and third harmonics are well understood in terms of the theory of surface impedance by Chambers and by Tsuji et al. The rapid broadening of the line shapes of much higher harmonics is attributed to the relation between the cyclotron orbit radius and the range of dislocation strain field. Identification of the orbit ω has been also made.     

Pulsed photoacoustic technique to measure the absorption coefficients of the highly transparent optical materials

A new technique of measuring the low optical absorption coefficient is described by using pulsed photoacoustic calorimetry. The frequency dependence of the photoacoustic signal is different owing to its main origin, either the bulk absorption or the surface absorption. The Fourier transform of the pulsed photoacoustic signal, generated by a pulsed CO₂ laser, is obtained as the frequency response of the photoacoustic signal. The ratio of the bulk absorption coefficient and surface absorption coefficient is acquired as 1:1.5.     

Reactivity of RuO species in RuO2/CeO2 catalysts prepared by a wet reduction method

The paper deals with the reactivity of RuO₂/CeO₂ prepared by a wet reduction method: ruthenium was supported on Ce(OH)₃, which was precipitated by alkali-hydrolysis of Ce(NO₃)₃, under a reduction condition with formaldehyde at pH 11 and transformed into RuO₂/CeO₂ catalysts by calcination in air at 773 K. The catalysts were investigated with an ESR technique and were tested for oxidation of propylene. They had no ESR signals by themselves at room temperature, but gave two sets of anisotropic signals upon contact with propylene. These signals were derived from the reaction products between RuO and propylene. The intensities of the signals were kept unchanged at room temperature for more than 1 h in the absence of excess propylene. The signals decayed in the presence of excess propylene and the upfield signal decayed more rapidly. A prior heating of the catalyst in air at 473 K or above caused the increase in the intensity of the upfield signal. The time course of the signal changes discriminated between ethylene and olefins with allylic hydrogen toward RuO species.     

Photocurrents of solar cells sensitized by aggregate-forming polyenes: Enhancement due to suppression of singlet–triplet annihilation by lowering of dye concentration or light intensity

Titania-based Grätzel-type solar cells were fabricated by the use of polyene dyes with various transition dipole moments. In the dye having the largest transition dipole among the samples, an aggregate was readily formed through dispersive interaction, and the photocurrent was increased when the dye concentration or the light intensity was lowered. This observation was ascribed to the suppression of the singlet–triplet annihilation reaction. In the dye having the smallest transition dipole, there was no sign of aggregate formation, and the photocurrent was decreased when the dye concentration or the light intensity was lowered.     

Concise synthesis of cyclic ethers via the palladium-catalyzed coupling of ketene acetal triflates and organozinc reagents. Application to the iterative synthesis of polycyclic ethers

The reaction of the ketene acetal triflates 9a-e and a zinc homoenolate 10 in the presence of a catalytic amount of Pd(PPh(3))(4) gave the enol ethers 11a-e in good yields. The products were converted to the corresponding cyclic ethers 14a and 14b by hydroboration and lactonization. The present methodology allowed us to synthesize the DE and GH ring segment of gambierol in a concise manner. Iterative syntheses of the polycyclic ethers 26 and 32 are also described.     

Silica monolithic membrane as separation medium. Summable property of different membranes for high-performance liquid chromatographic separation

We studied an applicability of a silica monolithic membrane as separation medium for high-performance liquid chromatography (HPLC). We prepared porous monolithic silica membranes having a three-dimensional network structure to cut and shape into a membrane separation medium. We evaluated chromatographic properties of a variety of solutes using a column containing the membranes with HPLC to elucidate summable property of the membrane separation media. In addition, we made brief study on separation of HbA1c in whole blood with the stacked" membranes having different surface characteristics in one column, which is a membrane column. We confirmed that the membrane column was able to separate HbA1c from other matrix in whole blood to some extent, and it also had an excellent ability for hydrophobic and ion exchange adsorption.     

Syntheses and properties of photochromic polymers of the mercury thiocarbazonate series

Photochromic vinyl polymers of the mercuric thiocarbazonate series were synthesized via the three sequences: (1) synthesis of p-(meth)acrylamidophenyl mercuric acetate(II) by the reaction of (meth)acrylyl chloride with p-aminophenyl mercuric acetate, followed by polymerization to afford corresponding polymers(III) and subsequent reaction with diphenyl- or di-β-naphthyl-thiocarbazone, (2) alternative preparation of III by the reaction of (meth)acrylyl chloride polymers with p-aminophenyl mercuric acetate, and (3) reaction of N-hydroxymethyl (meth)acrylamide polymers with p-amidophenyl mercuric thiocarbazonates. The photochromic behavior of these polymers was investigated to provide data which might indicate the effect of steric conditions on the isomerization of the photochromic components in polymers both under illumination and in dark recovery.