No abstract available

[en] The activity of precious meta catalysts in the wet oxidation of organic compounds was investigated. Ruthenium was the most active catalyst among the precious metals examined, and cerium (IV) oxide was the most effective support. The Ru/Ce catalyst rivaled homogeneous copper catalyst, which is used in the practical wastewater treatment, for the oxidation of n-propyl alcohol, n-butyl alcohol, phenol, acetamide, poly (propylene glycol), and acetic acid. In addition, it was especially effective for the oxidation of some compounds with high oxygen content such as poly (ethylene glycol), ethylene glycol, formaldehyde, and formic acid

[en] The MHD stability in a tokamak, especially the Mercier criterion, is quite sensitive to the equilibrium parameters. In the paper, we solved the free-boundary equilibrium with hollow current profile and, in usual cases, the code gives the solution with enough accuracy. Through a careful re-examination of the equilibrium, however, it was found that the equilibrium accuracy was reduced for increasing q-profile hollowness and, near the magnetic axis, the plasma occasionally tended to the inverse D shape, which reduces the Mercier stability index. This resulted in the misleading output of the paper; that is, the Mercier criterion can be violated for the high inverse q profile even for q₀ greater than 1. By the re-calculation of the Mercier criterion for equilibria with high accuracy, we conclude that, although the stability index reduces with increasing q₀, the Mercier criterion is not violated. We acknowledge many colleagues who pointed out the importance of the equilibrium accuracy and suggested the re-examination of the stability calculation. (author)

[en] The average concentration of SF6 in the atmosphere of the Northern Hemisphere has been rising since the 1970s. By comparing the SF6 concentration of groundwater and the historical record of atmospheric concentration, groundwater can be dated from about the 1970s to the present. We therefore need to collect samples using an SF6-free pump or similar device, which prevents contact of the sample with the atmosphere, thus ensuring that atmospheric SF6 does not mix with the sample. Reduction of both the time and effort for water sampling caused by this constraint will result in more efficient investigation. We have proposed a simple manually operated water sampling method using a well water sampler (well bailer bucket) for SF6-based dating of groundwater. During the process of groundwater sampling using a well bailer bucket, the sample comes into contact with the atmosphere. The calculation of SF6 transfer from gas to liquid phase indicates that during this process, the theoretical increase in the SF6 concentration of groundwater is less than 1%, which corresponds to a residence time of 0.2 years and is within the range of analysis accuracy of 3%. This simplified method using a well bailer bucket (the simple method) can obtain the same results as th e ordinarily used sampling method (the conventional method) in which water samples are collected without contact with the atmosphere. The difference between the SF6 concentration of the conventional method and that of the simple method is about 2% of the average value of both, which corresponds to about 0.5 years of apparent residence time. Even if sampled water comes into contact with the atmosphere during the sampling process by using the simple method, the dissolution of atmospheric SF6 into the sampled water is extremely small. Depending on the sampling depth and survey equipment, the simple method can reduce the sampling time (for example, a reduction of 60 to 70%, including preparation for sampling). The simple method, which does not use a pump, has no sampling depth restriction due to the pump head. Furthermore, the simple method can lessen the weight of equipment, reducing the burden on survey participants

No abstract available

[en] Free-electron laser (FEL) experiments have been conducted with the 38-MeV L-band electron linac at the Institute of Scientific and Industrial Research, Osaka University. It is a 1.3 GHz RF linac with a thermoionic gun, and equipped with two 12th and one 6th sub-harmonic prebunchers for producing the high-intensity single-bunch beam with a charge up to 67 nC/bunch. For oscillation experiments of FEL, the gun is replaced with that with a smaller cathode area in order to reduce the emittance of the beam. The normalized emittance has been measured to be 200 π mm-mrad. The linac is operated in the long-pulse mode and one of the 12th sub-harmonic bunchers and the 6th sub-harmonic buncher are operated, so that the time duration of the macropulse is 4 μs and the spacing between micropulses is 9.2 ns. The length of the micropulse is 30-40 ps and the charge in each micropulse is 2 nC. The electron beam from the linac is transported to a wiggler which has the period length of 6 cm and the number of periods of 32. The first half of the macropulse is lost in the transport line because the energy of electrons in that part gradually changes and there is a momentum slit in the transport line. An optical resonator is 5.53 m long and the round-trip time of light in it is 37 ns, which is precisely four times as long as the spacing of micropulses. Since the time duration of the macropulse passing through the wiggler is 1.8 μs, the number of amplifications of light in the cavity is 49. The first lasing was achieved in 1994 at wavelengths between 32 and 40 μm and preliminary results were reported at the l6th FEL Conference last year. The laser light was detected with a Ge:Be detector which has the time resolution of 3 μs. Since the time duration of the macropulse of the laser fight is estimated to be less than 2 μs, we could measure only the total energy in a macropulse of the output light

[en] The modification of JT-60U to a large and fully superconducting tokamak (JT-60SC) is proposed to demonstrate the high beta operation of the reactor relevant steady-state plasma and the applicability of the low activation ferritic steel characterized by a ferromagnetic property to plasma confinement devices. In order to improve economic and environmental suitability of tokamak fusion reactors, crucially important are the accomplishment of low circulating power operation in accord with a high pressure plasma and the establishment of utilization technology of low radio-activation materials to minimize the influence of radioactive waste to the environment. The JT-60SC device is designed to implement the steady-state research in a high performance plasma regime of a break-even class for a long duration (∼100 s or longer) sufficiently exceeding a current diffusion time. Physics and engineering design of JT-60SC is presented to address the issues of high beta plasma control, steady state plasma control and divertor heat and particle control with high performance steady-state plasmas non-dimensionally similar to the future reactor plasma and surrounded by ferritic steel. (author)

[en] In order to investigate the effect of polarization change on measurements of electron temperature profile from electron cyclotron emission (ECE) in a tokamak plasma, we have calculated the spatial evolution of the electric field of ECE propagating in the plasma. In the case of almost on-axis propagation, the Boyd's prediction is a good approximation, that is, the electric vector rotates with magnetic field. On the other hand, along horizontal sight line far from the axis the Boyd's prediction has a discrepancy of 3% from the numerical results. The effect of the polarization change is important for the measurement of ECE imaging in large tokamaks

[en] The π⁰π⁰ mass spectra and angular distributions around K Kbar-threshold and at 1.5 GeV in ppbar(at rest) → 3π⁰ in the Crystal Barrel experiment are reanalyzed by applying the new method, which is consistent with unitarity of S-matrix and expressed directly by resonance parameters. The effects of light σ-meson production are clearly seen to improve the fit with σ, in comparing with the fit without σ

No abstract available