Conversion electron measurement in the β<Superscript>-</Superscript>-decay of <Superscript>151</Superscript>Pr

The β^--decay of ¹⁵¹Pr produced by the thermal neutron-induced fission of ²³⁵U has been studied using an on-line isotope separator. From an internal-conversion electron measurement with a Si(Li) detector, K-conversion coefficients were obtained for 20 γ-transitions. Spins and parities of 6 excited levels in ¹⁵¹Nd were newly determined from the deduced multipolarities: even parities for the 543 and 627 keV levels, odd parities for 250 and 599 keV, (3/2, 5/2)⁺ for 685 keV, and (1/2, 3/2)⁺ for 880 keV. The level structure was compared with the rotation-vibration coupling Nilsson model. Received: 28 June 2002 / Accepted: 31 October 2002 / Published online: 25 February 2003 RID="a" ID="a"e-mail: ykojima@hiroshima-u.ac.jp Communicated by J. ?yst?     

Convenient synthesis of alpha-trifluoromethylated acyloins from alpha-hydroxy or alpha-amino acids

Alpha-trifluoromethylated acyloins (2 and 6) have been prepared from alpha-hydroxy acids (1), N-acylprolines (5) or N-acyl-N-alkyl alpha-amino acids (8) by novel transformation reactions with trifluoroacetic anhydride (TFAA) in the presence of pyridine. The former reaction of 1 could proceed through mesoionic 1,3-dioxolium-4-olates, whereas the latter two reactions of alpha-amino acids (5 and 8) could involve mesoionic 1,3-oxazolium-5-olates. The reaction of 1 with TFAA shows more potential for practical applications because of the ready availability of the starting materials and ease of manipulation.     

Experimental evidence for the hydrogen evolution site in photocatalytic process on Pt/TiO2

A hydrogen-deuterium isotope effect on the title reaction is observed. The separation factor of the reaction is found to be 5.3 ± 0.5, which is similar to the separation factor reported on Pt electrode, but different from that observed on TiO₂ electrode. The Pt sites are assigned to the reduction site on the catalyst.     

Particle-liquid mass transfer in viscoelastic media

The problem of mass transfer from a solid sphere to a viscoelastic fluid has been examined theoretically. It is shown that fluid elasticity increases marginally the mass transfer rate in the creeping flow regime. This will have serious implications on the mass transfer from bubbles if impurities are present. Some conclusions on mass transfer at high Reynolds numbers are also offered.     

Sleep disturbance by traffic noise: an experimental study in subjects' own houses using a portable CD player

The current study investigated the effect of noise on sleep in subjects' own houses using recorded traffic noises. A railway noise and two kinds of road traffic noise differing in level-fluctuations were used as stimuli. Subjects were exposed all night to the artificially controlled stimuli for 10 days through a portable compact disc (CD) player. The effect of noise on sleep was judged in three ways, namely whether the subject had switched off the CD player, a self-declaration of the subject based on a questionnaire, and the amount of arm movement of the subject during the night as measured by an actigraph. The results of the analysis of the self-declaration data showed that the thresholds where sleep disturbance began were 40-45 dB in for road traffic noise and about 35 dB for railway noise, which corresponded to 50-55 dB in L_A,Fmax of each train noise event. The results of the analysis of the actigraphy data showed a rapid increase in the incidence of mid-sleep awakening at sound pressure levels higher than 50 dB, for railway noise. However, neither of the road traffic noises showed such a tendency, as long as the sound pressure level was less than 55 dB, .     

Magnetic Hyperfine Fields of 151PmFe and 147NdNi

Low-temperature nuclear orientation (LTNO) experiments were performed on ¹⁵¹Pm implanted into iron and ¹⁴⁷Nd implanted into nickel. The γ-ray anisotropy measurements yielded values of the magnetic hyperfine field and the substitutional fractions of these ions in the host metals. An observed discrepancy between the substitutional fractions obtained from the 91 keV and 531 keV data on ¹⁴⁷NdNi is briefly discussed. This revised version was published online in September 2006 with corrections to the Cover Date.     

Adsorption of phenol in flow systems by a monolithic carbon cryogel with a microhoneycomb structure

Adsorption of phenol from an aqueous solution in batch and continuous flow systems using carbon gels with a microhoneycomb structure (carbon gel microhoneycombs, CMHs) was studied. The obtained monolithic CMHs had fairly straight channels, 25–45 μm in diameter, and the thickness of the walls which form the channels was around 5 μm. The CMHs showed 370 times lower hydraulic resistance when compared with a column packed with particles having the same diffusion path length as it. The obtained CMHs have a hierarchical micro-meso porous structure giving BET surface area in the range of 513–1070 m²·g^?1.When used for phenol adsorption from an aqueous solution, the CMHs quickly adsorbed phenol at first, and then, the uptake gradually increased, which indicates that the adsorption mechanism is based on not only simple physisorption. The phenol adsorption capacity increased with the increase in carbonization temperature of the CMH and the decrease in its hydrophilicity. CMHs carbonized at temperatures higher than 1073 K showed the highest phenol adsorption capacity which was around 160 mg·g^?1. The CMHs could continuously adsorb phenol from aqueous solutions, and their length of unused bed (LUB) values depended on operation conditions but were in the range of 0.3–0.7 cm. The experimental results indicated that carbon cryogels with a microhoneycomb structure have a high potential to be used for effective separation of phenol.