Keisuke Yasuda

Effects of Tb and Ba introduction on the reaction mechanism of direct NO decomposition over C-type cubic rare earth oxides based on Y2O3

C-type cubic Y2O3, (Y0.70Tb0.30)2O3+δ, and (Y0.99−xTbxBa0.01)2O2.99+δ (x = 0, 0.10, 0.20, 0.30, and 0.40) were prepared to investigate their catalytic performance for NO decomposition. In the direct NO decomposition process, NO is adsorbed on basic sites of the catalyst surface to form adsorbed nitrosyl, and the number of basic sites affects the NO decomposition activity. In particular, the negative effect of CO2 presence on the catalytic activity is related to the number of the surface basic sites. Furthermore, it was evidenced from temperature programmed desorption (TPD) of NO and IR measurements that adsorbed nitrosyl reacts with gas-phase NO and decomposes to N2. The effects of Ba2+ and Tb3+/4+ introduction on the activity of the catalyst are discussed based on this NO reaction mechanism. It is concluded that the principal effects of Ba2+ doping are an increase in the number of basic sites and the generation of oxide anion vacancies in the lattice. In addition, we demonstrate that Tb3+/4+ ions in the lattice facilitate O2 desorption and act as NO adsorption sites, so that the catalytic activity is significantly enhanced by Tb3+/4+ introduction, despite the small number of basic sites on the catalyst surface.

SUPPORT EFFECT ON THE COMPLETE OXIDATION OF ETHYL ACETATE OVER Pt CATALYSTS

Complete oxidation of ethyl acetate over Pt/CeO2–ZrO2–Bi2O3 catalysts prepared by a wet impregnation method was investigated. The Pt/CeO2–ZrO2–Bi2O3 catalysts completely oxidized ethyl acetate into CO2 and H2O at low temperatures without the formation of byproducts such as ethanol and acetaldehyde. The ethyl acetate oxidation activity correlates with the reducibility of the support such that a high reducibility gives high activity. By optimization of the composition and the Pt amount, complete oxidation of ethyl acetate was realized at a temperature as low as 190°C on a 10 wt.% Pt/Ce0.63Zr0.17Bi0.20O1.90 catalyst.

Measurement of Proton-Proton Bremsstrahlung at 389 MeV

Differential cross sections and analyzing powers for the proton-proton bremsstrahlung have been measured at 389 MeV incident energy. At the present kinematical conditions, an enhancement of the cross sections due to the Δ current contribution is predicted. The measured cross sections are larger than the theoretical predictions including the Δ current contribution.

First experiment at RCNP on pp-bremsstrahlung at 400 MeV

Abstract Proton-proton bremsstrahlung events were measured at 400 MeV proton energy. Two arm spectrograph and a liquid-hydrogen target system with well tuned beam provided good event identification.

Performance measurements of mixed data acquisition and LAN traffic on a credit-based flow-controlled ATM network

The high speed network is a key component in networked data acquisition systems. An ATM switch is a candidate for the network system in a DAQ (data acquisition system). We have studied the DAQ performance of the ATM network at the RCNP (Research Center for Nuclear Physics) at Osaka University. Data traffic on DAQ system has a very different traffic pattern from other network traffic. It may slow down the network performance. We have studied the network performance for several traffic patterns.