We have developed a new mm-submm telescope with a diameter of 1.85 m (hereafter, Osaka 1.85-m telescope) installed at the Nobeyama Radio Observatory. The scientific goal is to precisely reveal physical properties of molecular clouds in the Galaxy by obtaining a large-scale distribution of molecular gas, which also can be compared with large-scale observations in various wavelengths. The target frequency is ~230 GHz; simultaneous observations in J = 2–1 lines of 12CO, 13CO and C18O are achieved with a beam size (HPBW) of 2.7 arcmin. Here we present the progress of observations and the scientific results obtained by Osaka 1.85-m telescope. We note that these J = 2–1 data of the Galactic molecular clouds will be precious for the comparison with those of extra-galactic ones that will be obtained with the ALMA with the comparable spatial resolutions.

Some kinds of material in the environment due to the accident at the Fukushima Nuclear Power Plant have been contaminated by radioactive cesium (134Cs and 137Cs), which are represented by dehydrated sludge, surface soil and disaster wastes generated by the Great East Japan Earthquake. Treatment (transportation, temporary storage and incineration) and disposal of the contaminated materials should be carried out while ensuring the safety of radiation for the workers and the public. In this study, in order to provide the technical information for making the criteria, the dose estimation for scenarios on the treatment and disposal is conducted, based on the method used for driving the clearance levels in Japan. Minimum radioactive cesium concentration in contaminated material, that is, limiting activity concentration which is practicable for ordinary treatment and/or disposal, is calculated from the dose results, corresponding to the effective dose criteria indicated by the Nuclear Safety Commission of Japan. From the calculation result, it is suggested that it is necessary to forbid reusing the disposal site as construction, resident and agriculture in which the calculated doses for the public are higher than those in the other exposure pathways. Limiting concentration of radioactive cesium (134Cs and 137Cs) is derived to be 8,900Bq/kg for the external exposure pathway in landfill work under the condition of limited reuse of the site. In the case of the concentration below 8,900Bq/kg, the calculated dose of the resident due to direct and sky-shine radiation scattered in the air and ground from the interim storage place is less than 1mSv/y, irrespective of the distance from the storage place.

The sensitive analysis of radionuclide migration for the scenarios on deterioration or loss of safety functions expected in HLW disposal system due to the human error (initial defective scenarios) is performed in this study. Release rates for Cs-135 and Se-79 are estimated from Monte Carlo-based analysis. Maximum release rates of Se-79 and Cs-135 from natural barrier in initial defective scenarios for vitrified waste and overpack are approximately equivalent to that in normal scenario on all safety function working. Maximum release rate of Se-79 in initial defective scenario of buffer under the condition of colloidal migration is about 30 times as high as that in normal scenario. Maximum release rate of Cs-135 in initial defective scenario of plugs is about two orders of magnitude higher than that in normal scenario. These results especially indicate the need to understand the feasibility on two types of initial defective scenario, leading to the loss of restraint for colloidal migration in buffer and the loss of restraint with plugs from short-circuit migration.

We performed 12CO(J = 2 − 1) and 13CO(J = 2 − 1) line surveys of the galactic plane using the AMANOGAWA telescope (Nakajima et al. 2007) which covers 5° ≤ l ≤ 180° on a 7'.5 grid. The telescope beamsize and velocity resolution are 8.7′ ± 0.4′ and 1.3 km s−1. The resultant rms noise level is typically 0.12 K in TA*. We found a linear correlation between 12CO(J = 2 − 1) and 12CO(J = 1 − 0) and a curved correlation between 12CO(J = 2 − 1) and 13CO (J = 2 − 1), although the intensity ratios of these three lines have intrinsic variation. These correlations can be reproduced with simple radiative transfer equations suggesting some restrictions on the physical quantities of molecular gas on a galactic scale.

A Mg(OH)2–C transparent conductive film was prepared using the sputtering method by the initial formation of a Mg-C film generated by the alternate layering of Mg and C on a rotating substrate and subsequent exposure of the film to atmospheric water vapor. To examine the influence exerted by the Mg/C layers of the starting film sample on semiconductivity,evaluations of the electrical conductivity properties of the film during the hydroxylation process and the optical properties after the hydroxylation process were carried out. As a result, although no effects on the characteristics of the electrical conductivity properties associated with the composition or number of layers in the films could be confirmed, it was determined that the films possessed the characteristics of semiconductors. On the other hand, the optical properties were found to be affected by the composition and number of layers of the Mg/C films.

On the basis of monthly sampling of benthic life stages after larval recruitment of native and exotic mytilids (Musculista senhousia and Xenostrobus securis) in Japan, we examined variations in the spatio-temporal distributions of these mytilids in the brackish Lake Hamana along the Pacific coast of central Japan. We found similarities in their life histories, e.g. the number and the occurrence and duration of cohorts. However, M. senhousia densities were much higher than X. securis (nearly three times on average). We detected a contrast between the spatial distributions of these two mytilids. This contrast may be related intimately to the characteristics of the bottom sediments: much higher densities of M. senhousia were detected on the sediments of fine sand/mud-mixed gravels, whereas higher densities of X. securis were detected on artificial flattened rocks. Difference in microhabitat separation for these two mytilids may contribute to avoiding interspecific interactions during the benthic stages and thus to allowing the coexistence of these two mytilids on estuarine tidal flats in the brackish Lake Hamana.

Enhanced emissions at 0.98 μm of Yb3+ ions (2F5/2 → 2F7/2) incorporated in porous silicon are obtained when the host porous silicon is pre-annealed in an O2 containing atmosphere. Time decay characteristics are measured for the Yb 3+-related 0.98 μm emissions as well as for the emissions of these host porous silicon between 20 K and 300 K. The decay of the Yb3+ peak at 20 K is characterized with a fast (˜ 30 μs) and a slow decay time (≤ ˜ 400 μs), whereas it is fitted with one slow decay time (˜ 390 μs) at 300 K. The results are explained in terms of two optical centers: one has a fast fluorescent lifetime with a large temperature quenching, and the other has a slow fluorescent lifetime which is nearly constant between 20 K and 300 K.

In order to clarify the effect of mineral alteration on nuclide migration, we examined the processes, mechanisms, and kinetics of chlorite weathering, and the uranium concentrations in minerals and rocks at Koongarra, Australia. The observed concentrations of uranium in rocks were compared to those calculated. The sequence of chlorite weathering may be simply expressed as a chlorite → vermiculite → kaolinite conversion. These minerals occur as a function of depth, which corresponds well to uranium concentrations on the meter scale. Iron minerals, closely related to the uranium redistribution, are released during the weathering. The first-order kinetic model of the weathering process suggests that the weathering rate is not constant but time-dependent. The uranium concentrations are qualitatively proportional to the extent of the weathering; the weathered part having higher uranium concentration. Uranium mainly occurs with iron minerals, and sub micron sized saléeite, a uranyl phosphate, is one of the most probable uranyl phases associated with the iron minerals. The uranium fixation mechanisms are probably saléeite microcrystal coprecipitation and sorption to the iron minerals. Our model, which describes uranium concentrations in rocks as a function of time, shows that the transition zone (a vermiculite dominant area) plays an important role in the uranium migration. We have established that weathering of chlorite has affected the redistribution of uranium for more than one million years. The present study demonstrates the significance of mineral alteration when we estimate nuclide migration for geologic time.

Let us consider three vortex-filaments zj(t) with strength Γj (j = 1, 2, 3) in the complex plane C. Then the system of motion equations is given by

This system (E) is defined on V = C3 = Δ, where Δ = {(z1 z2, z3) ∈ C3; Zj = zk for j ≠ k} is the super-diagonal set of C3.

A modelling study was carried out to understand the effect of rock alteration on uranium radionuclide concentrations in rocks, in the vicinity of the Koongarra ore deposit, Australia. The one-dimensional, advection-dispersion-sorption model considers two important factors resulting from the process, mechanism and rate of chlorite weathering, one type of rock alteration that has occurred over a million-year period; (a) the changes in the distribution coefficients of uranium and thorium over time, and (b) that in rock porosity. The distribution coefficient and rock porosity at a given time, are expressed as average values of those of the coexisting minerals. By assuming a Darcy velocity of 0.9 m/y and an initial uranium concentration in the groundwater of 0.5 ppm, similar to present-day values, we were able to derive, from the finite-element modelling, uranium concentrations in the rock which are in good agreement with observed values. The calculated values of 230Th/234U activity ratios show a similar trend to those observed, although more experimental data are necessary to confirm the similarity. However, in the absence of the rock alteration, the calculated results did not agree with those observed. The present study suggests that rock alteration should be included in models used to predict uranium migration over long, geologic timescales.