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        검색결과 15

        1.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We present project updates of the next-generation infrared space mission SPICA (Space Infrared Tele- scope for Cosmology and Astrophysics) as of November 2015. SPICA is optimized for mid- and far-infrared astronomy with unprecedented sensitivity, which will be achieved with a cryogenically cooled (below 8 K), large (2.5 m) telescope. SPICA is expected to address a number of key questions in various fields of astrophysics, ranging from studies of the star-formation history in the universe to the formation and evolution of planetary systems. The international collaboration framework of SPICA has been revisited. SPICA under the new framework passed the Mission Definition Review by JAXA in 2015. A proposal under the new framework to ESA is being prepared. The target launch year in the new framework is 2027/28.
        4,000원
        2.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In order to reveal physical conditions of molecular gas in active galaxies (active galaxies mean both starbursts and AGNs in this paper), we carried out systematic observations (R = 19 ~ 120) of CO funda- mental band at 4.7 m in absorption with AKARI. We also made follow-up CO absorption observations at higher spectral resolution (R = 5000 ~ 1000) with Subaru. Recently, Herschel made extensive ob- servations of highly-excited CO lines in emission in the far-infrared. The two data sets (absorption and emission) sometimes provide us with apparently inconsistent results. One case is starburst galaxies: Sub- aru observations showed low temperature of molecular gas toward the starburst NGC 253, while Herschel detected highly excited CO lines in the starburst. This suggests that warm molecular clouds are more deeply embedded than newly formed star clusters. The other case is obscured AGNs; Herschel detected highly excited CO lines in emission in nearby AGNs, while AKARI and Subaru observations showed CO absorption only in some of the obscured AGNs. This could re ect the di erence of nature of molecular tori in these AGNs. We propose the combination of the absorption and emission observations as an e ective tool to reveal geometry of warm molecular clouds in active galaxies.
        3,000원
        3.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper provides an overview of the AKARI mission, which was the rst Japanese satellite dedicated to infrared astronomy. The AKARI satellite was launched in 2006, and performed both an all-sky survey and pointed observations during its 550 days in the He-cooled mission phases (Phases 1 and 2). After the He ran out, we continued near-infrared observations with mechanical cryocoolers (Phase 3). Due to a failure of its power supply, AKARI was turned o in 2011. The AKARI data are unique in terms of the observed wavelengths as well as the sky coverage, and provide a unique legacy resource for many astronomical studies. Since April 2013, a dedicated new team has been working to re ne the AKARI data processing. The goal of this activity is to provide processed datasets for most of the AKARI observations in a Science Ready form, so that more users can utilize the AKARI data in their astronomical research. The data to be released will include revised All-Sky Point Source Catalogues, All-Sky Image Maps, as well as high-sensitivity images and spectra obtained by pointed observations. We expect that the data will be made public by in the Spring of 2016.
        4,000원
        5.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We present the current status (as of August 2014) of SPICA (Space Infrared Telescope for Cosmology and Astrophysics), which is a mission optimized for mid- and far-infrared astronomy with a cryogenically cooled 3m-class telescope. SPICA is expected to achieve high spatial resolution and unprecedented sensitivity in the mid- and far-infrared, which will enable us to address a number of key problems in present-day astronomy, ranging from the star-formation history of the universe to the formation of planets. We have carried out the "Risk Mitigation Phase" activity, in which key technologies essential to the realization of the mission have been extensively developed. Consequently, technical risks for the success of the mission have been significantly mitigated. Along with these technical activities, the international collaboration framework of SPICA has been revisited, which resulted in la arger contribution from ESA than that in the original plan. To enable the ESA participation under the new framework, a SPICA proposal to ESA is under consideration as a medium-class mission under the framework of the ESA Cosmic Vision. The target launch year of SPICA under the new framework is the mid-2020s.
        3,000원
        6.
        2006.09 구독 인증기관·개인회원 무료
        We reported a P/M soft magnetic material with core loss value of , which is lower than that of 0.35mm-thick laminated material, by using high purity gas-atomized iron powder. Lack of mechanical strength and high cost of powder production are significant issues for industrial use. In order to achieve both low core loss and high strength by using inexpencive powder, the improvement of powder shape and surface morphology and binder strength was conducted. As the result, the material based on water-atomized powder with 80 MPa of TRS and 108 W/kg of core loss (W10/1k) was achieved.
        7.
        2006.09 구독 인증기관·개인회원 무료
        Intensive technological research on the Dry-bag CIP equipment was carried out to improve the dimensional accuracy and the productivity. The rubber mold design technology using FEM simulation during pressing was introduced, in order to achieve higher dimensional preciseness, and criteria for the selection of the In-line type or Off-line type, were established based on the powder flowability index proposed by Carr. Based on these research results, high productivity Off-line Dry-bag CIP equipment, which can realize good dimensional accuracy with high productivity, was developed even for non-granulated powders with poor packing density.
        8.
        2006.09 구독 인증기관·개인회원 무료
        We developed the copper core ball electroplated with Sn-Ag-Cu of the eutectic composition which used mostly as Pb free solder ball with high reliability. In order to search for the practicality of this developed copper core ball, the evaluation was executed by measuring the initial joint strength of the sample mounted on the substrate and reflowed and by measuring the joint strength of the sample after the high temperature leaving test and the constant temperature and the humidity leaving test. This evaluation was compered with those of the usual other copper core balls electroplated with (Sn,Sn-Ag,Sn-Cu,Sn-Bi) and the Sn-Ag-Cu solder ball.
        9.
        2006.09 구독 인증기관·개인회원 무료
        Several boride sintered bodies such as , , and were previously reported. In the present study, the sinterability and physical properties of chromium boride containing chromium carbide sintered bodies were investigated in order to determine its new advanced material. The samples were sintered at desired temperature for 1 hour in vacuum under a pressure by hot pressing. The relative density of sintered bodies was measured by Archimedes' method. The relative densities of addition of 0, 5, 10, 15 and 20 mass% composites were 92 to 95%. The Vickers hardness of the with 10 and 15 mass% composites were about 14 and 15 GPa at room temperature, respectively. The Vickers hardness at high temperature of the addition of 10 mass% composite decreased with increasing measurement temperature. The Vickers hardness at 1273 K of the sample was 6 GPa. The Vickers hardness of addition of composites was higher than monolithic sintered body. The powder X-ray diffraction analysis detected CrB and phases in containing composites.
        10.
        2006.09 구독 인증기관·개인회원 무료
        Recently, there has been a growing demand for soft magnetic materials with high conversion characteristics, due to the trend of electric devices to higher-frequency range. For ruduceing core loss in the high-frequency range, using finely grained and high-resistivity Fe-based alloy powder is most efficient methods. But, conventionally, there's been a compressibility problem for such powder. In this work, Fe-based alloy powder that offers both high resistivity and high compressibility was developed by studyuing composition of the powder, and reduction of core loss of P/M soft magnetic materials in the high frequency range was achieved.
        11.
        2006.09 구독 인증기관·개인회원 무료
        The new alloy1) is made from rapidly solidified Al-Ni-Zr-Ce aluminum alloy powder, and has the following unique mechanical characteristics:(1) The stress-strain curve shows a yield point; (2) The alloy shows high heat resistance; (3) Although the alloy is submicron particle diameter, it shows excellent creep resistance. We observed the micro structures of this new alloy, and it is thought that is based on the following reasons:(1) The dislocation strongly adheres to the alloy’s many crystal boundaries;(2) The added alloying elements have a small diffusion coefficient in aluminum;(3) The tiny intermetallic compound particles crystallizing at the grain boundary.
        12.
        2006.09 구독 인증기관·개인회원 무료
        We successfully developed Al-Si-Transition Metal (TM) -Rare Earth (RE) Powder Metallurgy (P/M) alloy with fine microstructure, which has high strength at high temperature. This material was compacted rapidly solidified powder and directly consolidated by hot extruding or forging. Before consolidating, rapid heating was performed on powder compaction in order to keep the fine microstructure in powder state. We have also investigated the processing conditions of this new alloy by computing simulations and experiments.
        13.
        2006.04 구독 인증기관·개인회원 무료
        In this study, nano grain W is fabricated by Severe Plastic Deformation-Powder Metallurgy (SPD-PM) process. W powder and W-Re powder mixtures are processed by SPD-PM process, a Mechanical Milling (MM) process. As results, a nano grain structure, whose grain size is approximately 20nm, is obtained in W powder after MM for 360ks. A nano grain W compact, whose grain size 630nm, has excellent deformability above 1273K. A nano grain W-10Re compact is composed of equiaxed grain, a grain growth is restrained and has low dislocation density after the large deformation; therefore it is considered that W-Re compact shows superplasticity.
        15.
        2005.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Because hand-written characters, especially drawn by a brush can give readers various impressions, they are not only a communication method but also art works. Authors have already investigated the relationship between brush motion analytical results and sensory testing results obtained from Japanese hiragana and reported quantitative evaluation method for the beauty of hiragana, In this paper, sensory tests for South Koreans who cannot recognize the word are carried out, compared with sensory testing results of Japanese. The evaluation objects are 6 hiragana drawn by 4 beginners and 2 experts, Semantic Differential Method based on 30 paired evaluation words are used in the sensory tests. Therefore South Koreans also feel the beauty in hiragana drawn by experts, as compared with by beginners. On the other hand it was confirmed that South Koreans couldnt recognize the difference among beginners. Judging from the factor analysis results, both Japanese and South Koreans selected stability as the 1st factor, there is interesting difference in the following orders.
        4,000원