“Gas Density Histogram (GDH)” is an observational counterpart of the probability density function (PDF) of the gas density of interstellar medium (ISM). We used 12CO data in (l, b) = (29°, 0) region from “FOREST unbiased galactic imaging survey with Nobeyama 45-m telescope (FUGIN)”, which is a large coverage survey in three CO (1-0) lines. Using the kinetic distance, we estimated the volume density of the voxel from the observed column density. The resultant GDHs of the inter-arm regions show lognormal or lognormal-like, but those in the spiral arm regions show flat-top shape.

We report a recent result of the FUGIN project, a Galactic plane CO survey using the Nobeyama 45-m Telescope and the FOREST receiver. In the third galactic quadrant, 42 square degrees are observed and 4752 molecular clouds are detected. Among them, 12 clouds are located at R (distance from the Galactic center) > 16 kpc. Molecular clouds at R < 16 kpc trace the Local, Perseus, and Outer arms.

We present the 12CO J=1–0, 13CO J=1–0, and C18O J=1–0 maps of the M17 giant molecular clouds (GMCs) obtained as a part of the Nobeyama 45m CO Galactic Plane Survey. The observations cover the entire area of M17 SW and M17 N clouds at an angular resolution of ~ 15″ which corresponds to ~ 0.15 pc. We found that the N cloud consists of a couple of twisted filaments, they are extended in parallel toward the Hii region. The typicall width of the filaments is ~0.5 pc in 13CO intensity map. Most of young stellar objects (YSOs) are located on the filaments which have a bright rim structure in 8μm at the filament edge facing the Hii region. Furthermore, the time scale of the YSOs formation on the bright rim is comparable with that of NGC 6618 cluster which provides UV photons for the region. This fact indicates that the cluster triggered to form YSOs in N cloud. We also investigated the geometry of the Hii region and GMCs by comparing spatial distribution of 12CO velocity channel map and infrared dark cloud, and then found that NGC 6618 is possibly formed by the cloud cloud colision.

We report a successful demonstration of a position control technique for carbon nanotube growth catalyzed by an iron nano-dot array, which was fabricated by using electron beam induced chemical vapor deposition (EB-CVD). Point irradiation of an electron beam with ferrocene source gas produced an amorphous carbon dot containing iron atoms that were uniformly dispersed into each dot, and its position could be precisely controlled. Vacuum annealing of the ferrocene based dots induced segregation of iron nano-particles, whose size was almost proportional to the beam irradiation time. After removing the carbon residue, an ethanol CVD process carried out at 800°C under 40 mmHg of ethanol vapor induced carbon nanotube growth from the dots. Many grown nanotubes were very thin, being 0.7 to 1.8 nm in diameter. These diameters were much less than that of the bottom iron particles.

The causes and nature of ice-sheet radio-echo internal reflections at deep layers in polar ice sheets are discussed, based on the dielectric properties of ice that have been measured at microwave frequency and radio frequency. The reflection coefficients of electromagnetic waves in ice sheets due to two causes the change in permittivity induced by changes in crystal-orientation fabrics with depth, and changes in conductivity induced by changes in acidity with depth - were derived respectively as a function of the frequency used in radar sounding and the temperature of ice, and both were compared quantitatively. It is shown that at single-plane boundaries the reflection coefficients due to the former cause are independent of frequency and temperature and that they are large enough to produce dominant internal reflections. In contrast, reflection coefficients due to the latter cause strongly depend on frequency and temperature. Since they are inversely proportional to the frequency, the latter cause can be dominant only when frequencies below about 60 MHz are used. Examination of previous observational data has suggested that not only changes in acidity but also changes in crystal-orientation fabrics exist at depths corresponding to the dates of earlier volcanic eruptions.

The relationship between ice fabric and the internal radio-echo reflections was investigated using observation data collected at Mizuho Station, Antarctica. The data were obtained by 179 MHz radio-echo sounding and the ice fabric was measured from 700 m Mizuho ice core. The dielectric permittivity tensor at given depths in the ice sheet was calculated from the ice fabric.

The calculated dielectric permittivity tensor showed that the ice sheet at Mizuho Station is a uniaxially birefringent medium. The symmetrical axis of rotation was the same as the flow line. In such a medium, theory predicts that the electric field vectors are allowed only in the two directions parallel and perpendicular to the flow line. The prediction coincided well with the observation: a strong signal was observed only when the transmitting antenna and the receiving antenna, kept parallel to one another, were oriented parallel or perpendicular to the flow line. However, the observed signal strength in these two directions differed from one another at each depth.

It is also shown that the power reflection coefficient due to the variation of ice fabric with depth is of approximately the same order as that due to the density change and is large enough to produce the predominant internal radio-echo reflections.

Dielectric anisotropy in ice Ih was investigated at 9.7 GHz with the waveguide method. The measurement of dielectric permittivity was made using single crystals collected from Mendenhall Glacier, Alaska. The result of the measurement shows that ϵ′‖c, the real part of dielectric permittivity parallel to the c axis, is larger than ϵ′⊥c the real part of dielectric permittivity perpendicular to the c axis. This tendency is similar to that at low frequencies in the region of the Debye relaxation dispersion. It can be proposed that ϵ′‖c>ϵ′⊥c in the HF, VHF and microwave frequency range. ϵ′‖c and ϵ′‖c depend slightly upon temperature but the dielectric anisotropy, ∆ϵ′=ϵ′‖c-ϵ′⊥c, is constant and becomes 0.037 (±0.007). Based on the present results, a simple caculation indicates that the maximum power reflection coefficient caused by the dielectric anisotropy is about −50 ∼ −80 dB, which is significantly larger than the power reflection coefficient observed in the ice sheet by radio-echo sounding, about −70 ∼ −80 dB. This leads to a conclusion that dielectric anisotropy is one of the dominant causes of internal reflections.