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In the collapsing phase of a molecular cloud, the molecular gas temperature is a key to understand the evolutionary process from a dense molecular cloud to stars. In order to know this, mapping observations in NH3 lines are required. Therefore, we made them based on the FUGIN (FOREST Unbiased Galactic plane Imaging survey with Nobeyama 45m telescope). The 6 maps were observed in NH3 (J,K) = (1,1), (2,2), (3,3) and H2O maser lines and obtained temperature maps; some show temperature gradient in a cloud. Additionally 72 cores were observed. These candidates were called as KAGONMA or KAG objects as abbreviation of KAgoshima Galactic Object survey with Nobeyama 45-M telescope in Ammonia lines. We show the results of two regions in W33 and discuss their astrophysical properties.
Documenting past changes in the East Antarctic surface mass balance is important to improve ice core chronologies and to constrain the ice-sheet contribution to global mean sea-level change. Here we reconstruct past changes in the ratio of surface mass balance (SMB ratio) between the EPICA Dome C (EDC) and Dome Fuji (DF) East Antarctica ice core sites, based on a precise volcanic synchronization of the two ice cores and on corrections for the vertical thinning of layers. During the past 216 000 a, this SMB ratio, denoted SMBEDC/SMBDF, varied between 0.7 and 1.1, being small during cold periods and large during warm periods. Our results therefore reveal larger amplitudes of changes in SMB at EDC compared with DF, consistent with previous results showing larger amplitudes of changes in water stable isotopes and estimated surface temperature at EDC compared with DF. Within the last glacial inception (Marine Isotope Stages, MIS-5c and MIS-5d), the SMB ratio deviates by up to 0.2 from what is expected based on differences in water stable isotope records. Moreover, the SMB ratio is constant throughout the late parts of the current and last interglacial periods, despite contrasting isotopic trends.
It has been indicated that low-luminosity active galactic nuclei (LLAGNs) are accelerating high-energy cosmic-ray (CR) protons in their radiatively inefficient accretion flows (RIAFs). If this is the case, Sagittarius A* (Sgr A*) should also be generating CR protons, because Sgr A* is a LLAGN. Based on this scenario, we calculate a production rate of CR protons in Sgr A* and their diffusion in the central molecular zone (CMZ) around Sgr A*. The CR protons diffusing in the CMZ create gamma-rays through pp interaction. We show that the gamma-ray luminosity and spectrum are consistent with observations if Sgr A* was active in the past.
A multiple parameter dating technique was used to establish a depth/age scale for a 171.3 m (145.87 m w.e.) surface to bedrock ice core (Bl2003) recovered from the cold recrystallization accumulation zone of the Western Belukha Plateau (4115 m a.s.l.) in the Siberian Altai Mountains. The ice-core record presented visible layering of annual accumulation and of δ18O/δD stable isotopes, and a clear tritium reference horizon. A steady-state glacier flow model for layer thinning was calibrated and applied to establish a depth/age scale. Four radiocarbon (14C) measurements of particulate organic carbon contained in ice-core samples revealed dates for the bottom part of Bl2003 from 9075 ± 1221 cal a BC at 145.2 ± 0.1 m w.e. (0.665 m w.e. from the bedrock) to 790 ± 93 AD at 121.1 m w.e. depth. Sulfate peaks coincident with volcanic eruptions, the Tunguska meteorite event, and the 1842 dust storm were used to verify dating. Analysis of the Bl2003 ice core reveals that the modern Altai glaciers were formed during the Younger Dryas (YD) (~10 950 to ~7500 cal a BC), and that they survived the Holocene Climate Optimum (HCO) (~6500 to ~3600 cal a BC) and the Medieval Warm Period (MWP) (~640 to ~1100 AD). A decrease in air temperature at the beginning and an abrupt increase at the end of the YD were identified. Intensification of winds and dust loading related to Asian desert expansion also characterized the YD. During the YD major ion concentrations increased significantly, up to 50 times for Na+ (background), up to 45 times for Ca2+ and Mg2+, and up to 20 times for SO42− relative to the recent warm period from 1993 to 2003. A warm period lasted for about three centuries following the YD signaling onset of the HCO. A significant and prolonged decrease in air temperature from ~2000 to ~600 cal a BC was associated with a severe centennial drought (SCD). A sharp increase in air temperatures after the SCD was coincident with the MWP. After the MWP a cooling was followed gradually with further onset of the Little Ice Age. During the modern warm period (1973–2003) an increase in air temperature is noted, which nearly reaches the average of HCO and MWP air temperature values.
A large amount (5 × 1010 M⊙) of hot gas is thought to exist in an extended (≈ 200 kpc) hot diffuse halo around the Milky Way. We investigate the competitive role of the different dissipative phenomena acting on the onset of star formation of this gravitationally bound systems in this external environment. Ram pressure, Kelvin-Helmholtz and Rayleigh- Taylor instabilities, and tidal forces are accounted for separately in an analytical framework and compared in their role in influencing the star forming regions. We present an analytical criterion to elucidate the dependence of star formation in a spherical stellar system on its surrounding environment, useful in observational applications as well as theoretical interpretations of numerical results. We consider the different signatures of these phenomena in synthetically realized colour-magnitude diagrams (CMDs) of the orbiting system, thus investigating the detectability limits and relevance of these different effects for future observational projects. The theoretical framework developed has direct applications to the cases of our MW system as well as dwarf galaxies in galaxy clusters or any primordial gas-rich star cluster of stars orbiting within its host galaxy.
We successfully fabricated corundum-structured α-(InFe)2O3 alloy films on sapphire substrates by inserting α-Fe2O3 buffer layers. The ion compositions in the α-(In1-xFex)2O3 films, x, were artificially tuned for the entire range from 0 to 1 by changing the ion precursor composition in source solution. Magnetic measurements revealed that the α-(In1-xFex)2O3 (x = 0.13) alloy film showed ferromagnetism at 5 K.
Corundum structured α-(GaFe)2O3 alloy thin films were obtained on c-plane sapphire substrates by the mist chemical vapor deposition method. Wide range of X-ray diffraction 2θ/θ scanning measurements indicated that these crystals were epitaxially grown on c-plane sapphire substrates and these are no other crystal oriented phase. The cross-sectional and plane-view transmission electron microscope images showed the growth along the c-axis of α-(GaFe)2O3 thin films on sapphire substrates, forming joint of columnar structure. The non-doped α-(GaFe)2O3 thin films showed ferromagnetic properties at 300 K, though the origin of ferromagnetism still remained unresolved. In order to enhance the spin-carrier interaction, Sn doped α-(GaFe)2O3 alloy thin films were fabricated on c-plane sapphire substrates. X-ray diffraction 2θ/θ and ω scanning measurement results indicated that the highly-crystalline films were epitaxially grown on substrates in spite of the Sn-doping.
The current trends in stimulated Brillouin scattering and optical phase conjugation are overviewed. This report is formed by the selected papers presented in the “Fifth International Workshop on stimulated Brillouin scattering and phase conjugation 2010” in Japan. The nonlinear properties of phase conjugation based on stimulated Brillouin scattering and photo-refraction can compensate phase distortions in the high power laser systems, and they will also open up potentially novel laser technologies, e.g., phase stabilization, beam combination, pulse compression, ultrafast pulse shaping, and arbitrary waveform generation.
Epitaxial Fe-Te-Se thin films were deposited by pulsed laser deposition at 250 ~ 600 °C on SrTiO3 (100, STO), MgO (100), LaAlO3 (100, LAO) and CaF2 (100) single crystal substrates. Best superconducting film was grown on CaF2: Tconset = 20.0 K and Tc0 = 16.18 K with Tdep = 300 °C, 45000 pulses, 3 Hz. The critical current density Jc at 4.2 K was 0.41×106A/cm2 at 0 T and 0.23×106 A/cm2 at 9 T. Angular dependence of Jc showed broad c-axis correlated peak when B ≥ 3 T.
Changes in critical current properties depending on growth temperature (Ts) were clarified for Ba-Nb-O-doped YBa2Cu3Oy (Y123) films deposited by YAG- and excimer-PLD. Due to the introduction of Ba-Nb-O-nanorods, a vortex-Bose-glass-like behavior emerged as irreversibility lines and in-field critical current densities (Jcs) were improved. Crossover magnetic fields (Bcr) and in-field Jcs increased with the increase in Ts for the Y123 films with nanorods. These Ts-dependent critical current properties were attributable to the changes in morphology of the nanorods with Ts and were independent of laser source in PLD apparatuses. For the fabrication of RE123 coated conductors containing nanorods, optimization of Ts with taking both materials of RE123 matrix and nanorod into account is necessary to achieve higher in-field Jc.
In fine-grained metallic materials, the dominant grain boundary (GB) process, such as dislocation emission, dislocation absorption, and dislocation pile-up, causes non-uniform deformation, which results in high yield stress and low ductility. When a nano-scale void is introduced, the dislocation activity enhancement around the void could inhibit GB fracture and enhance ductility. In this study, by considering nanocrystalline Cu models, the influence of an intragranular nano-scale void on the fracture process has been investigated through molecular dynamics simulation. The dependence of ductility enhancement on the grain size and void size has especially been discussed at low and room temperatures. Sufficient dislocation activity enhancement accompanied by optimal void growth causes a fracture mode transition from GB fracture to transgranular fracture. While the ductility enhancement strongly depends on the void size at low temperature, it depends on the grain size at room temperature. The strong dependence of ductility enhancement on the temperature is found in the case of relatively small grains.
Organic solar cells with PEDOT:PSS hole transport layer or P3HT:PCBM active layer deposited by a novel solution-based mist deposition technique were fabricated and demonstrated. The device with mist-deposited PEDOT:PSS layer showed higher short circuit current density and power conversion efficiency than those of the one with spin-coated PEDOT:PSS layers. The device with mist-deposited P3HT:PCBM layer also performed with higher power conversion efficiency. The results encourage the promising potential of the mist deposition method for device fabrication.
Poly(3-hexylthiophene) (P3HT) nanofibers were fabricated with an association of poly(vinyl pyrrolidone) (PVP) by electrospinning. A mixture of P3HT/PVP in a mixed solvent of chlorobenzene and methanol was electrospun to form composite fibers with 60 nm - 2 μm in diameter, followed by getting rid of PVP by selective extraction. After extraction, pure P3HT nanofibers were obtained as a spindle-like structure with wrinkled surface. The nanofibers obtained exhibit specific features of strong interchain contribution as investigated by UV-vis, fluorescence spectroscopic, X-ray diffraction (XRD), and photo-electron investigations. Bulk heterojunction P3HT:PCBM nanofibers with ~200 nm in diameters were also successfully fabricated by using the same technique. The preliminary results from the study of P3HT:PCBM nanofiber-based photovoltaic cells with conversion efficiency over 0.2% could be achieved.
A direct calorimetry method was developed and used to measure the electrocaloric effect (ECE). A temperature change ΔT of over 20 °C and an entropy change ΔS of over 95 J/(kgK) were procured at 33 °C and 160 MV/m in the high-energy electron irradiated poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) 68/32 mol% copolymers, which were larger than those of terpolymer blends (ΔT = 9 °C, ΔS=46 J/(kgK) at 180 MV/m and room temperature) and our earlier report on P(VDF-TrFE) 55/45 mol% normal ferroelectric copolymer (12 °C and 55 J/(kgK) at 80 °C). We observed that the β value ((8.7±0.6)×107 JmC-2K-1) in the equation of ΔS=1/2βΔD2 derived from ΔS - ΔD2 relation for irradiated copolymers was larger than that of the terpolymer blends ((5.4±0.5)×107 JmC-2K-1). It was also found that the irradiated copolymer showed a sharp depolarization peak at Td < Tm (maximum permittivity temperature), which is frequency independent, in the dielectric constant - temperature characteristics, a larger depolarization value at Td in the thermally stimulated depolarization current (TSDC) - temperature relationship, and a larger volume strain/longitudinal strain ratio over terpolymer blends. The giant ECE in irradiated copolymer is regarded as due to the greater randomness present in the relaxor state. In irradiated copolymers, the long all-trans chains are broken by the high-energy electrons, which make the small sized all-trans sequences more easily reorient along the electric field, more remarkably affecting the permittivity, TSDC, and volume strain.
In order to measure precisely the polarization of Crab Nebula and Cygnus X-1, we have been developing a hard X-ray polarimeter for balloon-borne experiments called PHENEX (Polarimetry of High ENErgy X-rays). It consists of several detectors called unit counters. The unit counter has a detection efficiency of 20% and a modulation factor of 53% at 80 keV. Up to now, we have finished the installation of eight unit counters to the polarimeter, that will be launched in Spring 2009 to observe the Crab Nebula. If the polarization of this source is more than 30%, the PHENEX polarimeter will be able to measure the degree and the direction of the polarization with errors less than 10% and 10°, respectively.
X-ray astronomy has been much advanced by three observations: spectroscopy, timing, and imaging. Also in the hard X-ray region, these three observations will be realized by ASTRO-H and XEUS. However, the observation of the polarization is at the moment left out in spite of its potential usefulness. This is because of the difficulty of developing polarimeters with high sensitivity. Since the origin of the polarization is often due to nonthermal radiation processes such as synchrotron radiation, observations in the hard X-ray region are possibly more important than those in the soft X-ray region: it is expected that the degree of polarization in the hard X-ray region would be higher than that at lower energies.
Following an outbreak of vanA-positive Enterococcus faecium in 2005 in Kyoto prefecture, regional surveillance of vancomycin-resistant enterococci (VRE) was initiated. This revealed vanA- or vanB-positive Enterococcus gallinarum in multiple facilities. Eighty-eight vanA-positive E. gallinarum faecal carriers from 12 facilities and ten vanB-positive E. gallinarum faecal carriers from eight facilities were found. Pulsed-field gel electrophoresis profiles of the first isolate from each facility showed that 11 of the 12 vanA isolates and three of the eight vanB-positive E. gallinarum isolates belonged to a single clone. This study confirms the clonal spread of vanA- or vanB-positive E. gallinarum in a region and underlines the importance of surveillance of VRE for the presence of vancomycin resistance determinants.
High crystallized thin InSb epitaxial growth directly on Si substrate was investigated by molecular-beam epitaxy (MBE). Experimental results indicated that suppressing the desorption of hydrogen atoms which terminated the dangling bonds of Si wafer surface and incorporation of As around the interface between film and Si substrate were the most important to obtained high crystallized InSb film. It could be achieved by the irradiation of As4 cluster beam onto the Si wafer just before film growth. Obtained thin InSb film showed mirror like surface, and its thickness was 0.7 μm. Its electron mobility was 47,600 cm2/V-s, and FWHM of HR-XRD rocking curve was about 300 arcsec. This InSb film on Si wafer was applied to Hall element, and it passed ordinary reliability tests.
An overview on current trends in stimulated Brillouin scattering and optical phase conjugation is given. This report is based on the results of the “Second International Workshop on stimulated Brillouin scattering and phase conjugation” held in Potsdam/Germany in September 2007. The properties of stimulated Brillouin scattering are presented for the compensation of phase distortions in combination with novel laser technology like ceramics materials but also for e.g., phase stabilization, beam combination, and slow light. Photorefractive nonlinear mirrors and resonant refractive index gratings are addressed as phase conjugating mirrors in addition.