Prolonged degradation of end-capped polyelectrolyte multilayer films

Cationic chitosan (CT) and anionic dextran sulfate (Dex) were layer-by-layer (LbL) assembled from aqueous solutions containing 1 M NaCl on a quartz crystal microbalance (QCM) substrate, and the original films ((CT-Dex)₃-CT)) were end-capped with LbL assembly from CT solutions containing 1 M NaCl and Dex solutions without NaCl. The enzymatic degradation of films by chitosanase was quantitatively analyzed by QCM in terms of numbers of end-capping steps. The degradation of films end-capped with (Dex-CT)₃ was considerably prolonged when compared to those end-capped with other end-capping steps. A mechanism for the prolonged degradation was proposed by quantitative QCM data and zeta potential results.     

Syngas production by biomass gasification using Rh/CeO2/SiO2 catalysts and fluidized bed reactor

We have been developed novel catalysts for gasification of biomass with much higher energy efficiency than conventional methods (non-catalyst, dolomite, commercial steam reforming Ni catalyst). From the result of the gasification of cellulose over novel Rh/CeO₂/SiO₂ catalysts, it is found that the gasification process consists of the reforming of tar and the combustion of solid carbon. We also tested novel Rh/CeO₂/SiO₂ in the gasification with air, pyrogasification, and steam reforming of cedar wood. As a result, Rh/CeO₂/SiO₂ gave higher yield of syngas than the conventional steam reforming Ni catalyst. Furthermore, we compared the performance between single and dual bed reactors. Single bed reactor was effective in the gasification of cedar, however, it was not suitable for the gasification of rice straw since a rapid deactivation was observed. Gasification of rice straw, jute stick, baggase using the fluidized dual-bed reactor and Rh/CeO₂/SiO₂ was also investigated. Especially, the catalyst stability in the gasification of rice straw clearly was enhanced by using the fluidized dual bed reactor.     

Resistance to sulfur poisoning of hot gas cleaning catalysts for the removal of tar from the pyrolysis of cedar wood

In the partial oxidation of tar derived from the pyrolysis of cedar wood, the effect of H₂S addition was investigated over non-catalyst, steam reforming Ni catalyst, and Rh/CeO₂/SiO₂ using a fluidized bed reactor. In the non-catalytic gasification, the product distribution was not influenced by the presence of H₂S. Steam reforming Ni catalyst was effective for the tar removal without H₂S addition, however, the addition of H₂S deactivated drastically. In contrast, Rh/CeO₂/SiO₂ exhibited higher and more stable activity than the Ni catalyst even under the presence of high concentration of H₂S (280 ppm). On the Ni catalyst, the adsorption of sulfur was observed by XPS and Ni species was oxidized during the partial oxidation of tar. In the case of Rh/CeO₂/SiO₂, the adsorption of sulfur was below the detection limit of XPS. This can be related to the self-cleaning of catalyst surface during the circulation in the fluidized bed reactor for the partial oxidation of tar derived from cedar pyrolysis.     

Catalyst Design of Pt-Modified Ni/Al2O3 Catalyst with Flat Temperature Profile in Methane Reforming with CO2 and O2

Pt(0.3)/Ni(10)/Al₂O₃, prepared by a sequential impregnation method, exhibited a more excellent performance in methane reforming with CO₂ and O₂ in terms of the catalytic activity and the temperature profile of the catalyst bed than Pt(0.3) + Ni(10)/Al₂O₃ prepared by a coimpregnation method, Ni(10)/Al₂O₃, Pt(0.3)/Al₂O₃, and Pt(10)/Al₂O₃. It is thought that this is because the surface Pt atoms on Ni catalyst can contribute to the enhancement of the catalyst reducibility.     

Determination of fatty acid composition by gas chromatography: II. Analysis with use of flame ionization detector

In this study known mixtures of four or five fatty acid methyl esters were analyzed collaboratively by gas chromatography with flame ionization detectors. The experimental data was treated statistically to examine inter- and intralaboratory scattering. More-over the effect of the use of correction factors was investigated. Even if only the specific analytical values that scattered a little were chosen, the averages of such values did not always approach the actual values. In some laboratories a sort of regularity was observed in the deviation of analytical values from real values throughout the analyses of four samples. The application of correction factors to the analytical values obtained by these laboratories resulted in a considerable decrease of interlaboratory scattering and deviation from the real values. When a constant amount of sample was injected, intralaboratory scattering was decreased, whereas interlaboratory scattering was not. Injection of large sample sizes caused deviation. From this collaborative study it was recommended that 0.5–1.0 μl of 20% solution be injected. Presented at the JOCS-AOCS Joint Meeting, Los Angeles, April 1972.     

High-intensity multi-bunch beam generation by a photo-cathode RF gun

A multi-bunch photo-cathode RF gun system has been developed as an electron source for the production of intense quasi-monochromatic X-rays based on inverse Compton scattering. The desired multi-bunch beam is 100 bunches/pulse with a total charge of 500 nC and a bunch spacing of 2.8 ns. We modified the gun cavity of a ‘BNL-type IV’ RF gun to allow a CsTe cathode plug in the end plate. The system uses a four-dipole chicane beam line to allow the injection of laser light normal to the cathode surface. We compensate the gun cavity beam loading caused by the high-intensity multi-bunch electron beam by injecting the laser pulse before RF power has filled the cavity. We have achieved a total intensity of 220 nC in 100 bunches with a bunch-to-bunch energy spread under 1.3% (peak-to-peak). This paper concentrates on experiments to generate the high-intensity multi-bunch beam with compensation of the bunch-to-bunch energy spread due to heavy beam loading.     

Dietary eritadenine-induced alteration of molecular species composition of phospholipids in rats

The effect of dietary eritadenine, a hypocholesterolemic compound found in the mushroomLentinus edodes, on the fatty acid and molecular species profiles of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) in the plasma and liver microsomes was investigated in relation to the hypocholesterolemic action of the compound in rats. Animals were fed the control or eritadenine-supplemented (50 mg/kg diet) diet for 14 d. Eritadenine supplementation significantly decreased the plasma concentrations of cholesterol and phospholipids, but not triglycerides. The PC/PE ratio of liver microsomes, but not plasma, was also markedly decreased by eritadenine. Eritadenine supplementation was found to increase the proportion of 18:2n-6 and, inversely, to decrease the proportion of 20:4n-6 and 22:5n-6 in plasma PC and liver microsomal PC and PE, indicating that eritadenine depressed the metabolism of linoleic acid. The effect of eritadenine on the profile of n-3 fatty acids was dissimilar in PC and PE. These changes in fatty acid composition were selectively reflected in the molecular species composition of both PC and PE; the extent of increase in 16:0–18:2 molecular species or decrease in 18:0–20:4 molecular species was apparently greater than that of other molecular species containing 18:2 or 20:4 in the sn-2 position. These results suggest that, in addition to the decrease in liver microsomal PC/PE ratio, the alteration of plasma PC molecular species composition might also participate in the hypocholesterolemic action of eritadenine.     

Decomposition of CCl2F2 over metal sulfate catalysts

Activity for hydrolysis of CCl₂F₂ (CFC12) on various metal sulfate was investigated. Zr(SO₄)₂ was found to be the most active while FeSO₄, Cr₂(SO₄)₃, Al₂(SO₄)₃, La₂(SO₄)₃ and Ce₂(SO₄)₃ had intermediate activity. MnSO₄, CoSO₄, and MgSO₄ showed low activity and SrSO₄, CaSO₄, and BaSO₄ had even less activity. The major carbon containing product was CO₂ and small amount of CClF₃ and CO were formed over several sulfates. The crystal structure of the sulfates was stable during decomposition of CCl₂F₂, and the conversion reached a steady state after initial decrease at 275 °C over Zr(SO₄)₂ catalyst. The concentration of surface hydroxyl was larger than that over AlPO₄-based catalysts and a reaction mechanism similar to that over AlPO₄-based catalysts was proposed.