Hydrotalcite-like compounds (HT) with 24%–48% Al3+-substitution have been synthesized in the Mg2+-Al3+-Fe(CN)64- system. Conditioning of the synthesized and air-dried compound with K4Fe(CN)64- solution at 80°C was essential to obtain the 80%–90% pure ionic Fe(CN)64- form on an equivalent basis. A linear decrease in ao with an increase in the mole ratio of R = Al3+/(Mg2+ + Al3+) was extended to R = 0.48. The formation of highly Al3+-substituted HTs has been corroborated by the decrease in the hexagonal lattice constant ao down to 3.016 Å. The ao value was independent of the interlayer anions. The CO2 adsorption profiles were dependent upon both the Al3+-substitution and the interlayer distance. The isosteric heat of CO2 adsorption was 43.3 kJ mol-1 in the range of adsorption of 20 to 40 cm3 g-1 at 298 K and 0.1 MPa.

Dissolution of amorphous silica or silicate is an important reaction to release silicic acid in natural water and this reaction is affected by several factors. The existence of a natural organic compound, tropolone, because of its abundance, is of particular importance. In the present study, the dissolution of amorphous silica in the presence of tropolone (HL) was investigated in an aqueous solution under acidic conditions. The dissolution is controlled by the reaction between silicic acid and tropolone (Si(OH)4 + 3HL + H+ ⇌ SiL3+ + 4H2O), where the conditional formation constant K = [SiL3+]/[Si(OH)4][HL]3[H+]). The solubility of amorphous silica in the presence of tropolone was significantly greater than that in pure water due to the formation of the Si-tropolonate complex in the solution. The acceleration of silica dissolution by tropolone depends on the reaction pH and tropolone concentration. The solubility of the amorphous silica in the tropolone solution at pH 1 was approximately ten times greater than in the 0.1 mol/dm3 HCl used as a reference. This increase in the solubility correlates to a K value of the Si-tropolone complex at each pH. From the solubility experiments, the conditional formation constants (log K) of the Si-tropolonate complex at each reaction pH 1, 2, and 3 were 6.39, 5.88, and 5.77, respectively. The significant acceleration of the dissolution of amorphous silica by tropolone at pH 1 can be attributed to the large formation constant of the Si-tropolonate complex.

We report detections of thermal X-ray line emission and proper motions in the supernova remnant (SNR) RX J1713.7-3946, the prototype of the small class of synchrotron dominated SNRs. Based on deep XMM-Newton observations, we find clear line features including Ne Lyα, Mg Heα, and Si Heα from the central portion of the remnant. The metal abundance ratios suggest that the thermal emission originates from core-collapse SN ejecta arising from a relatively low-mass (≲20 M⊙) progenitor. In addition, using XMM-Newton observations on a 13 yr time interval, we have measured expansion in the southeastern rim to be ~0.75″ yr−1 or ~3500 km s−1 at a distance of 1 kpc. Given this, we derive an upstream density to be ~0.01 cm−3, compatible with the lack of thermal X-rays from the shocked ambient medium. We also estimate the age of the remnant to be ~1200–1600 yr, roughly consistent with the idea that RX J1713.7-3946 is the remnant of SN 393.

Measurements of air and solid velocities were made in an air-solid two-phase flow in a horizontal pipe by the use of a laser-Doppler velocimeter (LDV). The pipe was 30 mm inner diameter, and two kinds of plastic particles, 0.2 and 3.4 mm in diameter, were conveyed in addition to fine particles (ammonium chloride) for air-flow detection. The air velocities averaged over the pipe cross section ranged from 6 to 20m/s and the solid-to-air mass-flow ratio was up to 6. Simultaneous measurements of both air and 0.2 mm particle velocities were found possible by setting threshold values against the pedestal and Doppler components of the photomultiplier signal.

As the loading ratio increased and the air velocity decreased, mean-velocity distributions of both phases increased asymmetrical tendency. I n the presence of 0.2mm particles, a flattening of the velocity profile was remarkable. The effects of the solid particles on air-flow turbulence varied greatly with particle size. That is, 3.4 mm particles increased the turbulence markedly, while 0-2 mm ones reduced it. The probability-density function of the air flow deviated from the normal distribution (Gaussian) in the presence of particles. Finally, the frequency spectra of air-flow turbulence were obtained in the presence of 0.2 mm particles by using a fast Fourier transform (FFT). As a result, it was found that t,he higher-frequency components increased with increasing loading ratio.

Measurements of air and solid-particle velocities were made in a vertical pipe two-phase flow by the use of a laser-Doppler velocimeter (LDV). Five kinds of plastic particles, diameters of which ranged from about 3 mm to 200 μm, were transported in a vertical pipe of 30 mm inner diameter. It was found that, the smaller the particle size, the flatter was the mean air velocity distribution for the same mass flow ratio of solids to air. Large particles increased air turbulence throughout the pipe section, while small particles reduced it. Both effects of promotion and suppression of turbulence were observed at the same time in the presence of particles of medium size, that is, the turbulence was increased around the pipe centre and reduced near the wall. The frequency spectrum of air turbulence normalized by the turbulence intensity was not changed by the large particles. In the presence of the small particles, the higher-frequency parts of the spectrum increased.

High-energy protons are generated by focusing an ultrashort pulsed high intensity laser at the Advanced Photon Research Center, JAERI-Kansai onto thin (thickness <10 μm) Tantalum targets. The laser intensities are about 4 × 1018 W/cm2. The prepulse level of the laser pulse is measured with combination of a PIN photo diode and a cross correlator and is less than 10−6. A quarter-wave plate is installed into the laser beam line to create circularly polarized pulses. Collimated high energy protons are observed with CH coated Tantalum targets irradiated with the circularly polarized laser pulses. The beam divergence of the generated proton beam is measured with a CR-39 track detector and is about 6 mrad.

Colletotrichum lagenarium is a plant pathogenic fungus, and produces melanin that is an essential factor for appressorial penetration into host tissues. The melanin biosynthesis pathway of C. lagenarium starts with pentaketide synthesis catalyzed by polyketide synthase Pks1p. We previously confirmed that the direct product of Pks1p is 1,3,6,8-tetrahydroxynaphthalene. Thus, melanin biosynthesis in this fungus requires the reduction of 1,3,6,8-tetrahydroxynaphthalene to scytalone. We made a double mutant 9141-144 from the thr1 mutant 9141 that lacks the ability to metabolize 1,3,8-trihydroxynaphthalene. The double mutant 9141-144 could metabolize neither 1,3,6,8-tetrahydroxynaphthalene nor 1,3,8-trihydroxynaphthalene. However melanin production by the double mutant was restored by THR1, indicating that Thr1p can metabolize both compounds in vivo. These results demonstrate that two enzymes, Thr1p and a deduced 1,3,6,8-tetrahydroxynaphthalene-specific reductase, are involved in the first reduction step of the melanin biosynthesis pathway of C. lagenarium.

The carbon-bearing magnetite (CBM) was prepared by the carbon-deposition on the H2- treated magnetite with CO2 at 300 °C. The CBM reacted with H2O and evolved H2 gas at 300- 350 °C. The surface of the CBM was composed of a new iron(II)oxide / carbon layer (CIOlayer). X-ray diffractometry and chemical analysis showed that the CIOlayer was transformed to an amorphous carbide phase by allowing to stand in Ar stream at 300 °C, which is so reactive as to decompose H2O into H2. The mole ratio of the evolved H2 gas to the evolved CO2 was nearly equal to that in the carbide (Fe3C) decomposition reaction with H2O. During the H2O decomposition, oxygen ions are transferred to the surface layer forming iron oxide. When the carbon-bearing Ni(II)-ferrite (CBNF) was used as the solid phase, the hydrogen evolution reaction takes place without decreasing in the carbon content in the CBNF, and the evolved H2 volume was approximately 8 times higher than that evaluated from the oxidized amount of the iron ions in the CBNF. This result suggests that some amount of oxygen in the CBNF is released while allowing to stand the sample in Ar stream at 300 °C. These H2 evolution reactions can proceed at low temperature of around 300 °C. This will provide us the way to establish a unique chemical heat pump system, where the waste heat around 300 °C be transferred to chemical energy of H2. The surface layer composed of iron(II) oxide/carbon is the key compound for this reaction.

The reactivity of the H2-activated Ni(II)- and Co(II)-bearing ferrites with different levels of metal substitution have been studied for CO2 → C decomposition in comparison with that of the H2-activated magnetite. Ni 2+ and Co2+ have been substituted for Fe2+ or Fe3+ in magnetite with the spinel-type structure up to 14 % and 26 % of the mole ratio of Ni2+ and Co2 + to the total Fe content respectively. The reactivity of the Ni(II)- and Co(II)-bearing ferrite increased with the level of metal substitution. Especially, the Ni(II) substitution significantly facilitated the CO2 → C decomposition in a batch system. The rates of H2-activation (reduction) and CO2-decomposition (oxidation) for N(II)-bearing ferrite were studied by a thermogravimeteric analysis. The rates of both H2-activation and CO2-decomposition were much improved in the Ni(II)-bearing ferrite with the Ni(II)/Fetoul mole ratio of 14%. It is considered that the reduced Ni(II) ions which were formed on the surface of the ferrite is very active to facilitate both dissociation reactions of 1) H2 → 2 Hads and 2) CO2→ Cads + 2Oads,. From the change in the lattice constant of the Ni(II)-bearing ferrite during the H2-activation and CO2-decomposition, the oxygens in CO2 were considered to be incorporated into the oxygen deficient spinel lattice of the oxygen deficient Ni(II)-bearing ferrite which had been formed by the H2-activation.

A maximum Al3+-substitution has been demonstrated to be 45 mole% of (M + Al) in the brucite layer of hydrotalcites. The chemical composition of the highly substituted hydrotalcites can be typically represented by [M0.55Al0.45(OH)2] [(CO3)0.225 · 0.50H2O] where M = Mg, Ni, Zn, and Co. It showed the small lattice parameters of a0 3.05–2.98 A in the hexagonal lattice, which corroborates Al3+-substitution in the brucite layer. The simultaneous thermal analyses (TG and DTA) and mass spectrometry (MS) study have been performed. The highly Al3+-substituted hydrotalcites also showed quite different isotherms for the CO2 adsorption. These materials adsorbed CO2 gas by removing water within the interlayer and showed the selectivity for CO2 adsorption: Cu–Al ∼Zn—Al < Co—Al < Mg—Al < Ni—Al. The Mg—Al and Co—Al hydrotalcite-like compounds showed a doubled amount of CO2 by removing carbonate ions within the interlayer.

Measured stability characteristics in a radial wall jet were compared with calculated results for a two-dimensional wall jet. It was found that the stability of the radial wall jet is similar in many respects to that of the two-dimensional wall jet. An exception is that the local amplification rate of the disturbance velocity is much higher than in the two-dimensional case. It was also found that quarter-harmonics appear in the non-linear region, as well as half-harmonics, and that their amplitude distributions show profiles similar to that of the fundamental component. Further, vortex patterns were visualised in water flow, and results corresponding to measurements in air flow and to the linear stability calculation were obtained.

The stability of a two-dimensional wall jet was studied theoretically and experimentally. As a result of the linear stability calculation, it was found that one eigenmode is separated into two modes when the Reynolds number is large, and inside a neutral stable curve in the α, R-plane there exists another neutral curve enclosing a stable region. Experimental results of small disturbances were compared with calculated results; agreement between them was satisfactory. It was found, further, that subharmonics of a predominant disturbance velocity component appear in the non-linear region.

An experiment was made on a turbulent boundary layer with adverse and favourable pressure gradients alternating twice along the stream. The most important findings of the present study are as follows. In the region of the adverse pressure gradient downstream of the strong acceleration, an internal boundary layer develops within the boundary layer. In this internal layer large advection of turbulent energy occurs and the flow is locally non-equilibrium even near the wall. As a result the usual logarithmic law and turbulence similarity in the viscous sublayer break down.