Scientific role of ACA for low-mass star-formation study     

Shigehisa Takakuwa  Daisuke Iono  Baltasar Vila-Vilaro  Tomohiko Sekiguchi  Ryohei Kawabe 《Astrophysics and Space Science》2008,313(1-3):169-173

We discuss the scientific role of the Atacama Compact Array (ACA), the Japanese contribution to the ALMA project, for low-mass star-formation study. Our recent observations of several low-mass protostellar envelopes in the submillimeter CS (J=7–6) and HCN (J=4–3) lines with the SMA and ASTE have revealed that these submillimeter emissions are more extended than ∼2000 AU and show different velocity structures from those traced by millimeter lines. These results suggest the importance of taking short-spacing informations the ACA can offer. Our comprehensive imaging simulations of these protostellar envelopes, as well as prestellar cores and debris disks, unprecedentedly demonstrate the scientific importance of ACA.  相似文献   

Calorimetric measurements of fusion enthalpies for Ni₂SiO₄ and Co₂SiO₄ olivines and application to olivine-liquid partitioning     

Toru Sugawara  Masaki Akaogi 《Geochimica et cosmochimica acta》2003,67(14):2683-2693

Calorimetric measurements of fusion enthalpies for Ni₂SiO₄ and Co₂SiO₄ olivines were carried out using a high-temperature calorimeter, and Ni and Co partitioning between olivine and silicate liquid was analyzed using the measured heats of fusion. The fusion enthalpy of Co₂SiO₄ olivine measured by transposed-temperature drop calorimetry was 103 ± 15 kJ/mol at melting point (1688 K). The fusion enthalpy of Ni₂SiO₄ olivine was calculated based on the enthalpies of liquids in the system An₅₀Di₅₀-Ni₂SiO₄ measured by transposed-temperature drop calorimetry at 1773 K, and was 221 ± 26 kJ/mol at its metastable melting point (1923 K). The fusion enthalpy of Ni₂SiO₄ is the largest among those of olivine group, this is caused by the large crystal field stabilization energy of six-coordinated Ni²⁺ in olivine. The larger fusion enthalpy of Ni₂SiO₄ can account for the large and variable partition coefficient of Ni between olivine and silicate liquid. Based on the comparison between partition coefficients calculated from thermodynamic data and those observed in partition experiments, it is considered that the magnitude of partition coefficients is primarily dependent on the heats of fusion of the components. Furthermore, the activity coefficients for Ni-, Co- and Mn-bearing components in magmatic liquid are nearly of the same magnitude.  相似文献   

A newly devised infra-red ground scanner and its application to geothermal research in volcanoes     

Daisuke Shimozuru  Tsuneomi Kagiyama 《Journal of Volcanology and Geothermal Research》1978,4(3-4)

A new infra-red radiometer for volcanological purposes consists of a commercially available infra-red optical unit (IR camera), mounted on a balloon-tracking theodolite in place of the telescope. The device has a motor-driven horizontal scan at two speeds, and the output signal is fed to a portable recorder. Thus, it is possible to obtain the horizontal temperature profile of an objective area. With successive scanning with different vertical angles of the camera, the spatial temperature distribution can be obtained.The IR ground scanner was successfully utilized at two volcanoes — Kusatsu-shirane and Mihara-yama, O-shima. Repeated IR surveys were made after minor eruptive events. Variations of the surface temperature with time were detected for both volcanoes. The IR scanner is also suitable for monitoring the time and temperature of eruptions from active vents.  相似文献   

A 100 m laser strainmeter system installed in a 1 km deep tunnel at Kamioka, Gifu, Japan   总被引：1，自引：0，他引：1  

Shuzo Takemoto  Akito Araya  Junpei Akamatsu  Wataru Morii  Hideo Momose  Masatake Ohashi  Ichiro Kawasaki  Toshihiro Higashi  Yoichi Fukuda  Shinji Miyoki  Takashi Uchiyama  Daisuke Tatsumi  Hideo Hanada  Isao Naito  Souichi Telada  Nobuo Ichikawa  Kensuke Onoue  Yasuo Wada 《Journal of Geodynamics》2004,38(3-5):477

We have installed a laser strainmeter system in a deep tunnel about 1,000 m below the ground surface at Kamioka, Gifu, Japan. The system consists of three types of independent interferometers: (1) an EW linear strainmeter of the Michelson type with unequal arms, (2) an NS-EW differential strainmeter of the Michelson type with equal arms and (3) a NS absolute strainmeter of the Fabry–Perot type. These are configured in L-shaped vacuum pipes, each of which has a length of 100 m. (1) and (2) are highly sensitive (order of 10⁻¹³ strain) and have wide dynamical range (10⁻¹³–10⁻⁶). Observations with strainmeters (1) and (2) started on June 11, 2003. (3) is a new device for absolute-length measurements of the order of 10⁻⁹ of a long-baseline (100 m) Fabry–Perot cavity by the use of phase-modulated light. This third strainmeter will be ready for operation before the end of 2004. The laser source of strainmeters (1) and (2) is a frequency-doubled YAG laser with a wavelength of 532 nm. The laser frequency is locked onto an iodine absorption line and a stability of 2 × 10⁻¹³ is attained. The light paths of the laser strainmeter system are enclosed in SUS304 stainless steel pipes. The inside pressure is kept to be 10⁻⁴ Pa. Consequently, quantitative measurement of crustal strains of the order of 10⁻¹³ can be attained by employing the laser strainmeter system of (1) and (2) at Kamioka. This resolving power corresponds to that of a superconducting gravimeter. Using the laser strainmeter system, we expect to determine parameters related to fluid core resonance, core modes and core undertone as well as other geodynamic signals such as slow strain changes caused by silent earthquakes or slow earthquakes.  相似文献   

Counter-clockwise rotation of the eastern part of the Mongolia block: Early Cretaceous palaeomagnetic results from Bikin, Far Eastern Russia     

Yo-ichiro Otofuji  Daisuke Miura  Koichi Takaba  Kazuhiro Takemoto  Kazutoshi Narumoto  Haider Zaman  Hiroo Inokuchi  Ruslan G. Kulinich  Petr S. Zimin  Vladimir G. Sakhno 《Geophysical Journal International》2006,164(1):15-24

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Operational Data Assimilation System for the Kuroshio South of Japan: Reanalysis and Validation   总被引：3，自引：5，他引：3  

Masafumi Kamachi  Tsurane Kuragano  Hiroshi Ichikawa  Hirohiko Nakamura  Ayako Nishina  Atsuhiko Isobe  Daisuke Ambe  Masazumi Arai  Noriaki Gohda  Satoshi Sugimoto  Kumi Yoshita  Toshiyuki Sakurai  Francesco Uboldi 《Journal of Oceanography》2004,60(2):303-312

We describe an operational ocean data assimilation system for the Kuroshio and its validation using a nine-year reanalysis (historical run from 1993 to 2001) dataset of upper-ocean state estimation in the North Pacific. The horizontal structure of volume transport of the Ryukyu Current System (RCS) is shown from the reanalysis: The RCS is connected to the flow of the subtropical gyre, and its volume transport gradually increases from south-east of Okinawa (5–10 Sv) to the east of Amami-Ohshima Island (20 Sv). Comparing the reanalysis with independent observations on the southeast slope of the Amami-Ohshima Island indicates that the root mean square differences (RMSDs) are 0.076 (0.037) m/s in the period of December 1998 to November 1999 (November 1999 to November 2000) respectively. The reanalysis field has a bias (3.1 Sv) of the volume transport of the RCS and the RMSD (3.5 Sv) which is larger than the observed variability (2.81 Sv). Surface velocity and the Kuroshio axis south of Japan are also examined. Comparison of the reanalysis and ADCP data gave maximum RMSD of 0.749 (0.271) m/s in the strong (weak) current regions, respectively. The annual mean value of the axis error is 19 km in 1998. The RMSD of the error is at most 50 km, in 294 cases in the observation period, which is smaller than the observed root mean square variability of the axis (64 km). This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Preparation of the standard solutions of nitrate and their application to seawater and freshwater     

Mitsuko Ambe  Junko Kajiwara  Toshio Yoshihara  Ken Sugawara 《Journal of Oceanography》1975,31(2):85-92

Responding to the recommendation at the first Meeting of the International Coordination Group for the Cooperative Study of the Kuroshio and Adjacent Regions (CSK) 1965, a series of nitrate standard solutions consisting of eight different concentrations ranging from 0 to 50g-at NO₃-N/l in 30.5 sodium chloride solution with the highest purity was prepared for nitrate-N determination in seawater. The solutions have been proved to be stable at least 520 days after preparation.The best way of handling and conditioning the copper-cadmium column was studied for securing the perfect and reproducible conversion of nitrate to nitrite for the procedure as proposed byWood et al. (1967).It was also shown that the method can be applied to freshwater samples by the addition of sodium chloride and adjusting pH properly.  相似文献   

Bunnoite,a new hydrous manganese aluminosilicate from Kamo Mountain,Kochi prefecture,Japan     

Daisuke Nishio-Hamane  Koichi Momma  Ritsuro Miyawaki  Tetsuo Minakawa 《Mineralogy and Petrology》2016,110(6):917-926

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134Cs and 137Cs in the North Pacific Ocean derived from the March 2011 TEPCO Fukushima Dai-ichi Nuclear Power Plant accident,Japan. Part two: estimation of 134Cs and 137Cs inventories in the North Pacific Ocean     

Michio Aoyama  Mizuo Kajino  Taichu Y. Tanaka  Tsuyoshi Thomas Sekiyama  Daisuke Tsumune  Takaki Tsubono  Yasunori Hamajima  Yayoi Inomata  Toshitaka Gamo 《Journal of Oceanography》2016,72(1):67-76

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A multiphase model for the intracluster medium     

Daisuke Nagai  Martin E. Sulkanen  August E. Evrard 《Monthly notices of the Royal Astronomical Society》2000,316(1):120-128

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