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        검색결과 27

        3.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We have observed 60 Weak-line T Tauri stars (WTTSs) toward the Chamaeleon star forming region using the AKARI Far-Infrared Surveyor (FIS) All-Sky maps. We could not detect any signi cant emission from each source even at the most sensitive WIDE-S band. Then, we have performed stacking analysis of these WTTSs using the WIDE-S band images to improve the sensitivity. However, we could not detect any signi cant emission in the resultant image with a noise level of 0.05 MJy sr-1, or 3 mJy for a point source. The three-sigma upper limit of 9 mJy leads to the disk dust mass of 0.01 M⊕. This result suggests that the disks around Chamaeleon WTTSs are already evolved to debris disks.
        3,000원
        6.
        2014.04 구독 인증기관·개인회원 무료
        The Ramsar Convention on Wetlands has so far two significant COPs in Asia: COP5 in Kushiro, Japan in 1993 and COP10 in Changwon, South Korea, in 2008. The Convention itself is an intergovernmental mechanism.   However, the mission of the Convention – conservation of wetlands and wetland resources – can only be achieved by participation of local municipalities and people. Besides, the Ramsar Convention has another unique aspect compared with other biodiversity-related treaties/conventions: it is created by NGOs and still located within an international NGO, namely IUCN. Therefore, it is crucial for wetland conservation to promote partnerships between the central government and local government as well as among people, NGOs and private sectors. Experiences of the Ramsar Kushiro Conference tell us that two factors are important to make real local participation possible: 1) CEPA; and 2) sense of meaningfulness. If you don’t know the purpose of the Convention and the COP, you are hardly interested in its preparation. So somebody should prepare some handy promotional kits for people to understand the purpose of conservation. We compiled various materials, requested experts/scientists to deliver lectures for teachers, taxi drivers, restaurants owners and waiters, hotel receptionists and kids. If possible, it is desirable to have a series of articles on local and national newspapers. You did attend the Conference, but once it’s over you tend to forget everything? If you feel you did contribute to something meaningful, you would like to continue doing something for it. In case of Kushiro City, it established the Kushiro International Wetland Center in early 1995. KIWC functions as a network of various wetland centers in the Kushiro region. JICA (Japan International Cooperation Agency) and KIWC have organized many international training courses not only for wetland managers but also for other conservation-related personnel. JICA has signed an MoU with the Ramsar Secretariat, and KIWC will host the EAAFP (East Asia - Australasian Flyway Partnership) meeting early next year. These efforts have been carried out for twenty years and will continue for future generations.
        7.
        2008.10 구독 인증기관·개인회원 무료
        Tetranychus evansi Baker & Pritchard occurs on solanaceous plants, and causes serious damage to a variety of crops in Africa and Europe; it has not been reported from Japan. Tetranychus takafujii Ehara & Ohashi was found on Solanum nigrum L. in Japan in 2001 and described as a new species in 2002. It is considered to be a Solanaceae-specialist too and it is feared to become a severe pest on solanaceous crops, once it invades them. Because T. takafujii is morphologically very similar to T. evansi, doubt has arisen about the difference between these two species. Here we avoid the issue of taxonomy and focus on a solution for the potential problems that may arise when either of the species invades solanaceous crops. The present study determines the susceptibility of three T. takafujii populations from Japan and six T. evansi populations from various countries to 11 acaricides. The LC50-values of all nine populations tested were lower than the recommended concentration of every acaricide. These results suggest that mites from all nine populations can be controlled with acaricides when they occur on crops.
        10.
        2006.09 구독 인증기관·개인회원 무료
        Core loss of soft magnetic powder cores have been focused on to achieve high efficiency of power supplies. In this study the effects of crystal grain size on core loss were investigated by changing heat treatment conditions. It was found that core loss is influenced by crystal grain size because eddy current loss decreased and hysteresis loss increased by making crystal grain size smaller, and it is also influenced by particle size.
        11.
        2006.09 구독 인증기관·개인회원 무료
        Titanium alloys and Titanium alloy-based particulate composites were synthesized using the blended elemental P/M route. First, processing conditions such as the fabrication of master alloy powder were investigated. Ti-6Al-4V, Ti-5Al-2.5Fe, Ti-6Al-2Sn-4Zr-2Mo, IMI685, IMI829, Timetal 1100 and Timetal 62S, and Ti-6Al-2Sn-4Zr-2Mo/ 10%TiB and Timetal 62S/10%TiB were then synthesized using the optimal processing conditions obtained. The microstructures and mechanical properties such as tensile strength and high cycle fatigue strength were evaluated.
        12.
        2006.09 구독 인증기관·개인회원 무료
        The 21st Century Frontier Program, which is one of the R&D programs funded by Korean government, was launched in 1999 to elevate the status of Korean science and engineering capabilities to the advanced nation in the strategic fields. Currently, 23 different fields of science and engineering programs are carried out by researchers in institutes, universities and industries. Center for Advanced Materials Processing (CAMP) was formulated in 2001 to develop the advanced materials as well as to improve the parts manufacturing process. The main role of CAMP is proposing and forecasting the long term vision in Materials Processing Technology and also supporting the project teams for their best performance in R&D. The CAMP program consists of 5 research areas such as, Multi-layer Ceramic Electronic Parts, Powder Formed Precision Parts, 3 Dimensional Polymer Based Composites, Functional Metal Sheets, Parts Integration Technology. An introduction of R & D activities at CAMP, specially focusing on powder metallurgy, wil be presented.
        13.
        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.
        14.
        2006.09 구독 인증기관·개인회원 무료
        We investigated the mechanism how the high green density can be provided during die lubricated warm compaction (WD). We observed and analyzed the densification processes of iron powders including different contents of an inner lubricant, and measured the lateral pressure at the die wall during WD in comparison with conventional compaction and warm compaction. As a result, the high density in WD was due to not only the particles-deformation enhanced by warming powders but also the particles-rearrangement promoted by reducing an amount of the inner lubricant rather than the die lubrication.
        15.
        2006.09 구독 인증기관·개인회원 무료
        Recently warm compaction techniques are focused on and commercialization of one high-density compaction process in the P/M industry. Another development is a new SEGLESS using a developed lubricant that reduces ejection force at room temperature compaction. It is possible to achieve high-density by reducing lubricant amount. In this paper we confirmed that green density was 7.35 g/cm3 at 686MPa of compaction pressure when the new SEGLESS was applied to relatively lower temperature warm compaction process, such as 80℃.
        16.
        2006.04 구독 인증기관·개인회원 무료
        Monosized germanium micro particles are prepared by a newly developed Pulsated Orifice Ejection Method. The obtained particles are categorized into two kinds of the microstructures as refined and coarse ones. The morphological difference is estimated to be determined by the undercooling level during nucleation. Actually, the increase in the temperature of the melt was effective in coarsening the microstructure, because the temperature of the melt intensely relates to the undercooling level. The transition temperature of coarse and refined microstructures is found to be 1300-1350K. Furthermore, a triggered nucleation could improve the crystallinity of the particles in the short separation.
        17.
        2006.04 구독 인증기관·개인회원 무료
        Mono-sized silicon particles were effectively fabricated by a novel way named pulsated orifice ejection method (POEM). The particles are with very narrow particles size distribution and very small standard deviation of mean particle size. There are two different types spherical silicon particles were found. One consists of many grains mainly in random boundaries. The other consists of two or three grains with only twin orientation relationships, even single crystal in cross-section was also found within this type of spherical silicon particles.
        18.
        2006.04 구독 인증기관·개인회원 무료
        Free-machining agent 'KSX' contains complex calcium oxide is developed. The effect of admix ratio of KSX on mechanical properties and machinability with two different cutting speeds is reported. KSX displays improved machinability without deterioration of mechanical properties up to 0.3mass% addition. It was observed that KSX is effective with a small addition of 0.1mass% at slower cutting speed, and increased of admix ratio is effective at faster cutting speed.
        19.
        2006.04 구독 인증기관·개인회원 무료
        The filling property of the binder treated iron based powder made of atomized iron powder was compared with that of the one made of reduced iron powder. The latter one showed a better filling property than the former one, although the original reduced powder showed a worse flow rate. Changing the particle size distribution of the original atomized powder from wide to narrow like the original reduced iron powder, improved the filling property of the binder treated powder. As a result, the particle size distribution of the original iron powder was found to strongly affect the filling property of the binder treated powder.
        20.
        2006.04 구독 인증기관·개인회원 무료
        Nb-Ti alloys were hydrogenated to prepare fine and contamination-free powders. Cracks were introduced in the alloys when they were annealed at 1473 K and cooled in a hydrogen atmosphere. The fragments produced by hydrogen-induced cracking are brittle and the friability enhanced with the Ti content of the alloy, which is beneficial for further refinement of particle size. We also demonstrate that Nb-Ti powders with the average particle size less than 1 m can be produced by ball milling at a temperature lower than 203 K. Furthermore, hydrogen-free powders can then be obtained by annealing above the temperature corresponding to hydrogen desorption from Nb solid solution.
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