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        검색결과 44

        21.
        2008.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The amorphous (at%) alloy strip was pulverized using a jet mill and an attrition mill to get flake-shaped powder. The flake powder was mixed with dielectric powder and its dispersant to increase the permittivity. The powders covered with dielectric powders and its dispersant were mixed with a binder and a solvent and then tape-cast to form sheets. The absorbing properties of the sheets were measured to investigate the roles of the dielectric powder and its dispersant. The results showed that the addition of powders and its dispersant improved the absorbing properties of the sheets noticeably. The powder sheet mixed with 5 wt% of powder and 1 wt% of dispersant showed the best electromagnetic wave absorption rate because of the increase of the permittivity and the electrical resistance
        4,000원
        23.
        2007.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Electromagnetic wave absorbing materials have been developed to reduce electromagnetic interference (EMI) for electronic devices in recent years. In this study, Fe-Si-B-Nb-Cu base amorphous strip was pulverized using a jet mill and an attritor and heat-treated to get flake-shaped nanocrystalline powders, and then the powders were mixed, cast and dried with dielectric powders and binders. As a result, the addition of powders improved the absorbing properties of the sheets noticeably compared with those of the sheets without dielectric materials. The sheet mixed with 2 wt% powder showed the best electromagnetic wave absorption, which was caused by the increase of the permittivity and the electric resistance due to the dielectric materials finely dispersed on the Fe-based powder
        4,000원
        24.
        2007.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study is conservation works trend since 1900. Objects for study are National Treasures and Treasures in Buddhism, in wooden architecture. And researched about the factor of conservation works, roof and tile, painting and dissolution conservation works cycle by dissolution, timber change ratio. The factor of conservation works is the most, roof and tile. Conservation works cycle by dissolution is 12.8 years. Painting cycle is 16.3 years. There are two concepts of conservation works, that is restoration and preservation. There are many restoration before 1960's. To 1960's the preservation to be many to 1970's many Restoration. And since the end of 1970's is Preservation. These reasons are conservation works history of object, the rule for Heritage protection, people on works, and study of architecture. history.
        5,200원
        25.
        2006.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The amorphous alloy strip was pulverized to get a flake-shaped powder after annealing at for 90 min and subsequently ground to obtain finer flake-shaped powder by using a ball mill. The powder was mixed with polyimide-based binder of , and then the mixture was cold compacted to make a toroidal powder core. After crystallization treatment for 1 hour at , the powder was transformed from amorphous to nanocrystalline with the grain size of . Soft magnetic characteristics of the powder core was optimized at with the insulating binder of 3wt%. As a result, the powder core showed the outstanding magnetic properties in terms of core loss and permeability, which were originated from the optimization of the grain size and distribution of the insulating binder.
        4,000원
        26.
        2006.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Preservation of wooden architecture by means of synthetic resin, is physical and chemical work. Synthetic resins are using for consolidation and restoration of decayed members. Since 1978, synthetic resin became useful preservation of architectural heritage in Korea. The first object was Chimgyeru of Songgwang-temple in Suncheon city. In the 1980s, have begun the care of materials for conservation on the architectural heritage, it was influenced according to authenticity of UNESCO Venice charter's principle, in 1964. In Korea, preservation of wooden architecture by means of synthetic resin that is sing many kinds of epoxies. Among the specific types of epoxies are araldite XN1023, SV427, etc. The use of synthetic resin have merits and demerits in the restoration for architectural heritage. The merit is that it is more smaller change with new members during preservation work. But the demerit is an irreversibility of the epoxy resin. In 1999, 'ICOMOS International Wood Committee' recommend contemporary materials and techniques, should be chosen and used with the greatest caution. And preservation work should reversible, as possible as technically. Therefore, should be data continous for preservation of wooden architecture by synthetic resin. Because data is very important work about a preservation of wooden architecture by synthetic resin. And should be try to think about new materials and techniques instead of synthetic resin, in the long view.
        5,500원
        27.
        2005.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The distribution and composition of marine floating debris were recorded from a training ship 'Kyeongyang' of Gangwon Provincial University at May 19-29, 2004 and Aug.24-31, 2004. The sampled area is the middle part of East Sea of Korea(the coast of Gangwondo and region of Ulleung island and Tokdo), divided into 27 unit segments on survey areas. Debris fabrication materials were categorized with 6 items using the following; styrofoam, paper & cardboard, net & rope, vinyl & plastic, floating metal & glass, man-made or natural wood. From the investigation on May,2004, total numbers of marine floating debris in the middle part of the East Sea of Korea was 996 individuals. The No. 1 and No. 2 unit segment located at south-west region of Ulleung Island showed higher density than others. The styrofoam and vinyl & plastic accounted for 72.8% of all debris fabrication materials. From the investigation on August, 2004, total numbers of marine floating debris in the coast of the Gangwondo of Korea was 2,473 individuals. The No. 13 and No. 14 unit segment located at the vicinity of Samcheok showed higher density than others. The styrofoam and vinyl & plastic amounted to 76.1%. In the coast of the Gangwondo, the vinyl & plastic showed the highest density of 6 items were 41.3% and 68.0% on May and August, respectively. The total numbers of marine floating debris on May and August were 3,399 individuals. Vinyl & plastic accounted for 59.4%(2,019 ind.) among all debris, next styrofoam 15.8%(537 ind.) and wood 11.2%(379 ind.).
        4,000원
        28.
        2005.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        연근해 어선에서 사용되는 저가이면서 고정도의 GPS 컴퍼스는 위성 신호의 차단 및 선박이 고속 선회시 선수방위의 산출이 불안정해지는 문제점을 지니고 있어 전자자기 컴퍼스를 이용하여 안정된 선수방위 검출이 가능하도록 고안한 하이브리드 GPS-전자자기 컴퍼스를 시작(試作)하여, 그 성능을 평가하고 고찰한 결과는 다음과 같다. 스텝모터를 이용한 선회각속도별 실험에서 GPS 컴퍼스는 선회각속도 25˚/sec 이하에서는 1회/sec 씩 0.1˚ 단위로 안정된 선수방위를 검출하였으나, 그 이상의 선회각속도에서는 선수방위를 검출하지 못하였다. 한편, 전자자기 컴퍼스는 선회각속도에 상관없이 항상 선수방위를 나타내었으나, 컴퍼스 오차를 내포하고 있어 GPS 컴퍼스에 비해 정밀도는 낮음을 알 수 있었다. 고정점과 차량으로 이동 중에 하이브리드 GPS-전자자기 컴퍼스의 선수방위 정보를 출력한 결과, GPS 컴퍼스가 정상적으로 작동한 경우에는 GPS 컴퍼스의 선수방위 정보가 출력되고, 그렇지 못할 경우에는 선수방위 정보가 출력되고, 그렇지 못할 경우에는 전자자기 컴퍼스의 선수방위에 컴퍼스 오차를 가감하여 출력됨으로써 선수방위가 안정적으로 제공되었다. 또한, GPS 컴퍼스와 전자자기 컴퍼스에 의한 선수방위의 유사성을 검증하기 위하여, 두 데이터의 이동거리에 대한 선수방위를 이용하여 공분산분석을 행한 결과, 두 컴퍼스의 선수방위는 95%의 신뢰수준으로 유사성이 검증되었다.
        4,000원
        29.
        2004.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근 들어 노트북, 통신장비 등 고성능 전자기기들은 산업수요의 특성상 소형화와 경량화 추세가 가속화되고 있으며, 컴퓨터, 냉장고, 에어컨 등 가전제품에 있어서도 안정한 전류공급 및 역률의 향상이 의무화되고 있다. 따라서 내부에 사용되는 부품의 고주파화, 고효율화, 손실감소를 위한 고성능 연자성코아 (그림 1. 참조) 개발의 필요성이 한층 증대되고있는 실정이다. (중략)
        3,000원
        30.
        2004.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근 개발되고 있는 전자자기 컴퍼스를 이용한 소형어선의 항행자동화시스템을 구축하기 위한 기초 연구로서, 부두에 계류된 선박에서 각종 장비의 가동 시켰을 때 나타나는 컴퍼스 오차 변화를 측정하여 비교 분석한 결과를 요약하면 다음과 같다. 1. 목선에서 85kW의 집어등을 점등하였을 때, 조타용 자기컴퍼스는 7˚편서되었고, 전자자기 컴퍼스는 13˚~16˚ 까지 편서되는 것으로 나타났다. 2. FRP 어선에서 13OkW의 집어등을 점등하였을때, 전자자기 컴퍼스는 19˚~23˚ 까지 편동되는 것으로 나타났다. 3. 강선에서 225kW의 전력으로 각종 장비를 가동 시킬 때, 가동전과 비교하여 컴퍼스 오차의 차분은 조타용 자기 컴퍼스에서는 13˚ 편서되고, 전자자기 컴퍼스는 상갑판에서는 68˚ 편서되었고, 선수루 갑판과 조타실 및 컴퍼스갑판에서는 각각 16˚, 32˚, 20˚ 편동되어 나타났다. 4. 소형어선의 항행자동화시스템에 전자자기 컴퍼스를 활용하기 위해서는 선박내에서 사용하는 각종 장비에 의해 발생하는 컴퍼스 오차를 측정하여 적절하게 수정하여 사용해야 할 것으로 판단된다.
        4,000원
        31.
        2002.11 구독 인증기관·개인회원 무료
        Human embryonic stem (hES) cells can be induced to differentiate into tyrosine hydroxylase expressing (TH+) cells that may serve as an alternative for cell replacement therapy for Parkinson's disease (PD). To examine in vitro differentiation of hES (MB03, registered in NIH) cells into TH+ cells, hES cells were induced to differentiate according to the 4-/4+ protocol using retinoic acid (RA), ascorbic acid (AA), and/or lithium chloride (LiCl) followed by culture in N2 medium for 14 days, during which time the differentiation occurs. Immunocytochemical stainings of the cells revealed that approximately 21.1% of cells treated with RA plus AA expressed TH protein that is higher than the ratio of TH+ cells seen in any other treatment groups (RA, RA+LiCl or RA+AA+LiCl). In order to see the differentiation pattern in vivo and the ability of in vitro differentiation-induced cells in easing symptomatic motor function of PD animal model, cells (2 10 cells/2) undergone 4-/4+ protocol using RA plus AA without any further treatment were transplanted into unilateral striatum of MPTP-lesioned PD animal model (C57BL/6). Following the surgery, motor behavior of the animals was examined by measuring the retention time on an accelerating rotar-rod far next 10 weeks. No significant differences in retention time of the animals were noticed until 2 weeks post-graft; however, it increased markedly at 6 weeks and 10 weeks time point after the surgery. Immunohistochemical studies confirmed that a reasonable number of TH+ cells were found at the graft site as well as other remote sites, showing the migrating nature of embryonic stem cells. These results suggest that in viかo differentiated hES cells relieve symptomatic motor behavior of PD animal model and should be considered as a promising alternative for the treatment of PD.
        40.
        2001.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        우리나라 동해안 명태어장의 어업환경 개선을 위한 기초연구로서 , 1998년 6, 7월과 1999년 5, 7, 8월에 걸쳐서 강원도 고성군 근해에서 사조묘로 수거 한 침체어구의 실태를 조사·분석하였다. 1. 폐어구는 어업활동에 의해서 발생된 것으로 저자망과 통발의 2종류였다. 2. 폐어구의 무게는 저자강이 1,170 t,통발이 4 t 으로, 저자망이 압도적으로 많았다. 3. 마일당 저자강의 수거량은 1998년 22.74 t에서 1999년 10.72 t 으로 12.02 t 감소 하였다. 4. 폐어구 수거율은 1998년 38.0%, 1999년 41.9%로 낮았고 CPUE는 1998년 11.27 t /회, 1999년 7.48 t /회이었다. 5. 사조묘에 의한 본 조사방법은 어장에서 발생한 침체어구의 수거에 유효한 수단이라고 생각된다.
        4,000원
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