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We will report the activities of the VERA single-dish observations. We are carrying out single-dish observations with two purposes. The first purpose is the monitoring of known H2O maser sources. At present, we are carrying out monitoring observations for 312 H2O maser sources at intervals of two months. The second purpose is the search for new water maser sources. We selected 901 target sources from the AKARI FIS Bright Source Catalogue. We found 61 new H2O maser sources.
In this proceeding paper, we introduce the recent results of Galactic maser astrometry by mainly focusing on those obtained with Japanese VLBI array VERA. So far we have obtained parallaxes for 86 sources including preliminary results, and combination with the data obtained with VLBA/BeSSeL provides astrometric results for 159 sources. With these most updated results we conduct preliminary determinations of Galactic fundamental parameters, obtaining R0 = 8.16 ± 0.26 kpc and Θ0 = 237 ± 8 km/s. We also derive the rotation curve of the Milky Way Galaxy and confirm the previous results that the rotation curve is fairly flat between 5 kpc and 16 kpc, while a remarkable deviation is seen toward the Galactic center region. In addition to the results on the Galactic structure, we also present brief overviews on other science topics related to masers conducted with VERA, and also discuss the future prospect of the project.
An unresolved X-ray emission extends along the Galactic plane, so-called the Galactic diffuse X-ray emission (GDXE). The characteristic feature is three K-shell lines of Fe at 6.4, 6.7, and 6.9 keV. Recently, superposition of faint point sources, such as Cataclysmic variables (CVs) and Active binaries (ABs) is thought to be a major origin, although it is under debate which sub-class mostly contribute. We re-analyzed the Suzaku archive data and constructed spectral models of ABs, magnetic CVs (mCVs), and non-magnetic CVs (non-mCVs). The GBXE is explained by combination of those models; non-mCVs and ABs mainly contribute while mCVs account for ~10% or less of the 5–10 keV flux. On the other hand, the GCXE and GRXE spectra cannot be represented by any combination of the point sources, indicating another origin would be required.
The region south of the reflection nebula NGC1333 in Perseus is an active star forming region including numerous Herbig-Haro objects and at least 5 protostar candidates with molecular outflows and far-infrared emission. It has been actively studied in various wave bands (e.g. Aspin et al 1994 and references therein). We observed this region with ASCA with the primary objective to detect X-rays from the protostars embedded deep in the molecular cloud.
The metal in the intracluster medium (ICM) has been ejected or stripped from galaxies. Thus measurements of the metal distribution and the relative abundance of elements, in particular Si/Fe, are important to study the evolution of galaxies, as well as to study the chemical evolution of the ICM. We present the results from ASCA observations of Abell 496 cluster of galaxies. A496 is a nearby rich cluster with a central cD galaxy. At the redshift z=0.0327 of A496, 1 arcmin is 53kpc, where we assumed H0 = 50kms−1Mpc−1, q0 = 0.5. A496 is known as a cooling flow cluster. Edge and Stewart (1991) obtained the mass flow rate of and the cooling radius of 177 ± 52kpc.
The complex radio source Sgr A is embedded in a region near our Galactic Center. The dynamical center of our Galaxy is considered to be Sgr A*, the compact non-thermal radio source. Dynamical mass within ~0.1 pc from Sgr A* has been estimated to be ~ 3×106 M⊙. This places Sgr A* to be a candidate of a massive blackhole (Eckart and Genzel, 1997 and reference therein).
We propose an X-ray all sky monitor for Japanese Experimental Module (JEM) on the space station. Considering practical circumstances, we show as a case study that the all sky monitor with slit hole cameras is most promising for monitoring the short-term and long-term X-ray transients. We call this all sky monitor as MAXI (Monitor of All-sky X-ray Image). Position determination of gamma-ray bursts could be achieved with accuracy less than one degree observing the X-ray component of the burst. Weak X-ray sources such as active galactic nuclei could be also monitored with time resolution less than one day. The X-ray all sky monitor will work to discover X-ray novae and transient phenomena and give us the alarm for further detailed observations. The obtained data will be also used for archival study.
Interplanetary scintillation has observed high-latitude streams which show low speeds (≤400 km/s) within 0.3 AU and high speeds (≥700 km/s) beyond 0.3 AU. The foot points of these streams were located in the Hel coronal holes or at their boundaries. Since the IPS measurement is biased by one or several mechanisms, we investigated whether this acceleration phenomena could be caused by bias effects or not. Speed increase of more than 100 km/s is left without being explained by the bias effects.
The High Energy Transient Explorer 2 is a small scientific satellite designed to detect and localize gamma-ray bursts (GRBs). The coordinates of GRBs detected by HETE-2 will be distributed to interested ground-based observers within seconds of burst detection, thereby allowing detailed observations of the initial phases of GRBs. HETE-2 was launched successfully on October 9, 2000. The GRB positions will start to be delivered after a few months of the complete testing and calibration of the spacecraft system and the science instruments.
Variability of the light curves of the short-period eclipsing binary system GR Tau (, almost-contact binary) is studied. It is found that GR Tau experienced both the state which is characterized by asymmetric light curves and the state characterized by symmetrical light curves.
The management of extrapulmonary small cell carcinoma has not been standardised to date. This study reviewed the clinical course, management and survival outcomes of patients with extrapulmonary small cell carcinoma in the head and neck region.
Nine patients with extrapulmonary small cell carcinoma in the head and neck were included in this study.
Five patients received radical surgery followed by adjuvant chemotherapy or radiotherapy or both. Two other patients were treated with chemotherapy consisting of CPT11 plus cisplatin or CPT11 plus cisplatin plus VP-16 three times. Two other patients received chemoradiotherapy consisting of S-1 or CPT11 plus cisplatin. The median overall survival was 14.5 months, with a three-year survival rate of 23.7 per cent.
The prognosis of extrapulmonary small cell carcinoma is generally poor. Further prospective multicentre studies are required for better understanding of disease entities and response to treatment modalities.
Hyalinizing clear cell carcinoma is a rare minor salivary gland neoplasm. The treatment of choice is surgical resection with or without post-operative radiotherapy. This tumour often demonstrates a good prognosis.
We report a case of hyalinizing clear cell carcinoma arising in the nasopharynx. A 27-year-old female presented with progressive hearing disturbance and tinnitus. On examination, an expansile mass was observed in her nasopharynx. Biopsy was performed and the pathology results returned as clear cell carcinoma.
Results and conclusion:
Surgical resection was performed trans-orally accompanied by trans-palatal approach. She has no recurrence during more than two years of follow up.
We studied the electrical properties of thermally treated V2O5-CuO-Fe2O3-P2O5 (vanadate) glasses under reducing high-vacuum conditions. The glasses were prepared by using a melt-quenching method and then applied on Al2O3 substrates as ∼40μm-thick films. The glass films were then heat treated at 375−550°C under a vacuum of 10−6 Pa. Powder X-ray diffraction showed the formation of complex oxides of both MxV2O5 (M = Cu, Fe; x = 0.12−1.3) and vanadium oxides (VOx; x = 1.5−2.5). The resistivity of the glass film crystallized at 550°C measured at 50°C and 300°C were 1.8 × 100 Ωcm and 2.8 × 10−1 Ωcm, respectively, which was 10 times lower than that of the film crystallized in air. The Seebeck coefficient was −132 μV/K at 50°C and −130 μV/K at 300°C. These results show that the vanadate glasses crystallized under the appropriate condition become potential candidate materials for semiconductor and thermoelectric application.
Pd deposits on Ni(111) have been studied by low energy ion scattering spectroscopy. We found that two different types of epitaxial growth exist: Pd[11 2]//Ni[11 2] and Pd[11 2]//Ni[11 2] at substrate temperature of 300 K. The Pd(111) planes grow as mixed domains of 50 % each. Surface alloying of the Pd-Ni system was confirmed for deposition at 300 K in which Pd atoms displace first-layer Ni atoms, with an outward displacement of 0.4 Å with respect to first layer Ni atoms.
A newly invented static rock breaker using TiNi shape memory alloy has been proposed. The breaker consisted of compressively pre-strained TiNi rods of 15mm in diameter and 29mm in height and a pair of two-layered wedge type platens of steel, and required no accessory equipments other than heating apparatus. The maximum breaking force per unit length of the breaker was 3 to 5MN/m. The total breaking force was about 300 to 900kN, depending on the number of TiNi rods used. To examine the practicality, the breaker has been applied to concrete wall of building, natural boulder, etc. It was confirmed that the breaker was not lack in terms of performance and was possible to control the direction of crack initiation and propagation. It can be concluded that TiNi shape memory alloy has a bright prospect as a solid pressure source.
Solidification of a nodular iron casting was simulated by an undercooling nucleation and diffusion controlled growth model. Simulated cooling curves were similar to measured ones but estimating nodular size distribution requires improving the model.
Magnetic properties of nanocrystalline alloys produced by crystallization of Fe-Cu-Nb-Si-B amorphous alloys have been investigated. The best result is obtained at the annealing conditions where the main phase is bcc and it is very important to suppress the formation of Fe-B compounds with large magnetocrystalline anisotropy. Homogeneous and ultrafine grain structure has an important effect to improve the magnetic properties. Conclusively, soft magnetic properties of nanocrystalline alloys are related to various factors such as formed phases, ratio of amorphous phase, intrinsic magnetocrystalline anisotropy and magnetic interaction from grain boundary phase.
Production Engineering R‘‘void-free’ metallization is proposed. It is shown that void formation is suppressed when the TiAl3 intermediate layer is formed at the interface between the Al alloy and reactively sputtered TiN barrier metal films. We have investigated the relationship between void formation and coverage of the intermediate layer. It is found that a coverage of more than 60 % TiAl3 perfectly suppresses void formation. The interfacial reaction is achieved by using ‘soft TiN', which arises from the short migration length of the sputtered particles impinging on the substrate surface when dc power is decreased. The soft TiN film includes many vacancies and crystallographically disordered regions which easily cause rearrangement of the TiN films by movement of Ti atoms during annealing. It is thought that these Ti atoms compensate vacancies in the Al-Si-Cu film and suppress the formation of Al voids.
Electromagnetic and thermoelectric characteristics of a sodium-cobalt oxide, NaxCoO2, were investigated. A precise control of Na nonstoichiometry was successfully facilitated by an unusual synthesis method named “rapid heat-up” technique. With increasing x, the absolute value of resistivity (ρ) monotonically decreased, while the value of thermoelectric power (S) increased, giving rise to a drastic enhancement in the thermoelectric power factor, i.e. S2 / ρ. Simultaneously enhanced thermoelectric power and reduced resistivity of the present compound are difficult to be understood within the framework of a conventional band picture. Moreover, for samples with the solubility limit Na content, i.e. x = 0.75, we discovered an unconventional electronic transition at Tm = 22 K, which may be induced by the strong-correlation effect of 3d electrons.