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PKS 1830-211 is a strong, flat-spectrum compact double source with a component spacing of 1 arcsecond. Observations of PKS 1830-211 were made with the Japanese domestic VLBI network at 2.3 GHz and 8.4 GHz bands in sessions between December 1991 and November 1994. The Usuda 64 m (ISAS) and Kashima 34 m (CRL) telescopes were used for all observations, and were used in conjunction with the Mizusawa 10 m (NAO) for observations in 1994. In addition, the total flux was measured with the Usuda 64 m at both bands. Data was recorded using K3 and K4 formatters and recorders, and correlated with NAOCO (the New Advanced One-unit COrrelator of the National Astronomical Observatory).
We have made aperture synthesis observations of CS(2-1) emission using the Nobeyama Millimeter Array (NMA), and obtained ~ 2” × 3” (0.005 × 0.008 pc) resolution image to investigate the velocity structures of Orion-KL. We found not only well-known expanding doughnut but the expanding hemisphere in the Orion-KL hot core.
We have made aperture synthesis multifield observations of Orion Molecular Cloud-1 (OMC-1) in the CS (J=1-0) line using the Nobeyama Millimeter Array (NMA), and obtained 9” resolution maps over 10’ length. The OMC-1 ridge shows a wiggled structure. The position angle of whole the ridge is ~ 0° - 10°, but ~ 20° - 30°around the clumps. It is possible to make this structure by the magnetic field with a position angle of ~ 150°. We also found filamentary structures in the northwest of Orion-KL, with a length-width ratio of more than 25, which are made by the gas flow from Orion-KL.
On February 12, 1997 the world’s first dedicated VLBI spacecraft, HALCA, was successfully launched as the space borne element of the VSOP mission. This paper describes the calibration observations that have been undertaken so far with this spacecraft.
The region containing Haro 4-255 FIR is studied in CS (1-0) with the 45 m telescope and the Nobeyama Millimeter Array. We have detected intense CS outflow. The CS abundance is found to be enhanced in the outflow lobe. The aperture synthesis data show two groups of emission, one of which is likely to impede the blueshifted CS lobe.
We have made aperture synthesis maps of Orion-KL in NH3(1,1),(2,2) and CS(J=l-0) emissions using the Nobeyama Millimeter Array. Both NH3 and CS maps show new detailed structures that have not been recognized before. Two NH3 filaments in the size of ~0.45 pc x0.04 pc are found extending to the northwest direction of Orion-KL. These filaments are associated with the HH objects and the finger-like H2 emissions; they are probably formed through the interaction with high velocity, highly channeled winds from the KL region. The CS maps show, on the other hand, shell structures around IRc2 as well as the well-known rotating disk. These shells coincide with the two lobes of the shock-excited H2 emission, being interpreted as the shock-compressed shells of ambient molecular gas interacting with the outflow from IRc2.
It is known that stars in GMCs are often born as clusters. Recently, near infrared imaging has enabled us to study the young stars within molecular clouds (e.g., Lada & Lada 1991). Orion Molecular Cloud 2 (OMC2) is located 12' north of the Trapezium cluster in the Orion A cloud, and contains a cluster of about 20 near-IR sources and several FIR sources distributed within a diameter of 0.2 pc (Rayner et al... 1989; Johnson et al. 1990; Mezger, Wink, & Zylka 1990). By large scale mapping observations using the NRO 45 m telescope, this infrared cluster is found to be associated with a dense molecular core (Tatematsu et al. 1993, Umemoto et al. 1993). The region was observed using the Nobeyama Millimeter Array (NMA) to elucidate the structure and cluster formation process within a core.
We present VLBI maps of the 6.7 GHz methanol maser emission in 32 sources obtained using the Japanese VLBI Network (JVN) and the East-Asian VLBI Network (EAVN). All of the observed sources provide new VLBI maps, and the spatial morphologies have been classified into five categories similar to the results obtained from European VLBI Network observations (Bartkiewicz et al. 2009). The 32 methanol sources are being monitored to measure the relative proper motions of the methanol maser spots.
Recent progress on the superconducting and normal state properties characteristic to the organic metals β-(BEDT-TTF)2X are presented. Out of a systematic study on the β-(BEDT-TTF)2X salts, including β-(BEDT-TTF)2 trihalide mixed crystals, with the superconducting transition temperature (Tc) varying from 8 K to below 1 K, empirical rules for various factors governing the Tc in this class of organic metals have been extracted. In addition to the low- and high-Tc states, with Tc=l K and 8 K, respectively, a new superconducting state with Tc=2 K was found in α-(BEDT-TTF)2I3. A particular attention is paid for the correlation between Tc and resistivity. In addition, a correlation between Tc and the anisotropy of coherence length is also considered.
Poly(2,5-thienylene vinylene), PTV, can be conveniently prepared via a precursor route to give coherent films suitable for optical measurements. Photoexcitation above the band gap at 1.8 eV gives rise to two transient absorption peaks at 0.44 eV and 1.0 eV that are associated with bipolarons that live for times of order a few ms at 80 K. Photoluminescence, comparable in intensity to the Raman scattering, is found at energies above the band edge, and we assign this to a hot recombination process. Pump and probe measurements of the induced bleaching at 2 eV show a very fast rise and initial fall time, which are within the 100 fsec resolution of the measurement.
We report our results for the temperature dependence of the Hall coefficient and in-plane resistivity for the asymmetric-donor-based quasi-2D Molecular crystal τ- (P-S,S-DMEDT-TTF)2 (AuBr2)1(AuBr2)y (y≈0.75). Using a recent “geometrical representation” of the weak-field 2D Hall conductivity developed by N.P. Ong [Phys. Rev. B 43, 193 (1991)], we model the temperature dependence of these electronic transport properties in terms of the temperature dependence of the scattering path length and its anisotropy along the 2D Fermi surface.
Several ternary Fe-Pt-Pd alloys with the compositions of Fe-(25-x) at% Pt-x at% Pd and Fe-y at% Pt-(30-y) at% Pd were investigated to study their phase transformations in order to develop ductile ferromagnetic shape memory alloys appearing around room temperature. Alloys were prepared by vacuum floating induction melting, followed by hot rolling at 1000°C and homogenization at 900° C. Homogenized alloys were heat treated at 650°C for various periods of time in vacuum for atomic ordering in encapsulated quartz tubes, and quenched into iced water. It was found that in general the transformation temperatures changes with heat treatment time. In the case of Fe-23at.%Pt-2at.%Pd, Ms temperature increased and the difference between Ms and Mf increased with increasing heat treatment time, which was different from Fe3Pt where a degree of order becomes one. As heat treatment time increased, there was a tendency in that a strong first-order transformation in the disordered state was replaced by a weak first-order transformation. The Curie temperature of the alloys rose drastically with the addition of Pd, along with the transformation temperatures. Fe-23at.%Pt-2at.%Pd showed good shape memory effect after 8 hours of heat treatment at 650°C. This alloy showed much better shape recovery than any other binary Fe-Pt and Fe-Pd shape memory alloys.
Composite film of carbon nanotube (CNT) and polytetrafluoroethylene (PTFE) was formed with despersion fluid of CNT and PTFE. The film showed high electrical conductivity in the range of 5-13S/cm. This conductive film was applied on the stainless steel bipolar plate for the polymer electrolyte membrane fuel cell (PEMFC) as anticorrosion film. This coating decreased the contact resistance between the surface of bipolar plate and the membrane electrode assembly (MEA) of the PEMFC. Therefore, the output power of the fuel cell was increased by 1.6 times.
The number of facilities in which customers make contact with cats before eating and drinking, called ‘cat cafés’, has recently increased in Tokyo, Japan. In a survey to clarify the possibility of zoonotic transmission in Giardia duodenalis, the infection rates of G. duodenalis in 321 stool samples of cats from 16 cat cafés, 31 pet shops, and the Animal Care and Consultation Center of Tokyo were 19·1% (22/115), 1·2% (1/85), and 2·5% (3/121), respectively. In the molecular analysis of 26 G. duodenalis isolates, 6 samples from 2 cat cafés belonged to the zoonotic genotype assemblage A I, and 20 other samples were of assemblage F. Moreover, phylogenetic analysis of glutamate dehydrogenase (GDH) and triosephosphate isomerase (TPI) genes of the 20 assemblage F isolates revealed 2 major lineages. The 6 assemblage A isolates belonged to the same cluster with regard to the GDH gene; however, 2 of the 6 isolates belonged to a different cluster from the other 4 isolates with regard to the TPI gene. Therefore, a risk of transmission from cats to humans is suggested because of the detection of zoonotic Giardia genotypes in cat cafés.
We investigated the risk of diphyllobothriasis from ingestion of wild Pacific salmon in Japan by surveying Diphyllobothrium plerocercoids in 182 salmon samples obtained from Japan. The plerocercoids were not detected in chum salmon (Oncorhynchus keta) (0/26), called Akizake in Japan, caught between September and November. However, the detection rate of plerocercoids in chum salmon, called Tokishirazu in Japan, caught between early April and June, was 51.1% (24/47) with an average of two plerocercoid larvae per fish. The detection rates of cherry salmon (Oncorhynchus masou) and pink salmon (Oncorhynchus gorbuscha) were 12.2% (10/82) and 18.5% (5/27), respectively, and the average number of plerocercoids per fish was 0.45 (37 larvae/82 fishes) and 0.22 larvae (6 larvae/27 fishes), respectively. Plerocercoids isolated from O. keta and O. masou were identified as Diphyllobothrium nihonkaiense on the basis of molecular analysis of the cox1 and nad3 genes. Moreover, four tapeworms (three from O. keta and one from O. masou) were obtained by infecting golden hamsters with plerocercoids. The morphological features of these tapeworms were similar to those of D. nihonkaiense isolated from humans. Therefore, we think that O. keta and not O. masou is the most important source of plerocercoid infections in Japan.