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        검색결과 151

        85.
        2007.04 구독 인증기관·개인회원 무료
        89.
        2006.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        전자파 자기장 발생 장치를 개발하여 제작한 후, 이를 수경재배와 배지경의 양액 공급관에 장착하여 물에 자기장을 쬔 자화수 처리의 유무에 따른 수질 성분변화, 배추와 상추의 생장량 변화, 그리고 성분 변화를 분석하였다. 자화수 처리구는 무처리구에 비해 비타민 C 함량이 상추 2.8배, 배추 1.2배로 더 많았다. 또한 자화수 처리에 의한 생장촉진 효과는 상추의 수경과 배지경 재배에서 현저히 나타났으나 배추의 토경재배는 자화수 처리의 효과가 미미하였다. 따라서 토경재배 상추에서 자화수 처리에 의해 생장과 비타민의 함량을 높일 수 있을 것으로 기대된다.
        4,000원
        92.
        2006.09 구독 인증기관·개인회원 무료
        The mechanical properties of ceramics materials can be tailored by designing their microstructures. We have reported that development of texture can be controlled by slip casting in a strong magnetic field followed by heating even for diamagnetic ceramics such as alumina. A strong magnetic field of 12T was applied to the suspension indcuding alumina powder to rotate each particle during slip casting. The sintering was conducted at the desired temperature in air without a magnetic field. C-axis of alumina was parallel to the magnetic field. Bending strength of textured alumina depended on the direction of oriented microstructure.
        93.
        2006.09 구독 인증기관·개인회원 무료
        This work will report a highly textured β-Si3N4 ceramic by aqueous slip casting in a magnetic field and subsequent pressureless sintering, Effects of the sintering aids, polymer dispersant, pH and stirring time on the stability of the Si3N4 slurries were studied. The textured β-Si3N4 with 97 % relative density could be obtained by slip casting in a magnetic field of 12 T and subsequent sintering at 1800 oC for 1 h. The textured microstructure is featured by the alignment of c-axis of β-Si3N4 crystals perpendicular to the magnetic field, and the Lotgering orientation factor, f, is determined to be 0.8.
        94.
        2006.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The relationship between electrical properties of superconductor and externally applied magnetic field was studied to develop a magnetic field sensor. The electrical resistance of the superconductor was increased by applying external magnetic field and even after removal of the magnetic field. This behavior was related to the magnetic flux trapped in the superconductor, which penetrated through the material by the external magnetic field. Some portion of the superconductor was changed to a normal state by the trapped magnetic flux. The appearance of the normal state yielded to enhance the electrical resistance.
        4,000원
        95.
        2006.04 구독 인증기관·개인회원 무료
        We have demonstrated that textured nanocomposites can be fabricated by slip casting followed by partial oxidation. reaction sintering of mixed suspensions of and SiC powders in a high magnetic field. The sintered density was changed by the degree of oxidation at 1200C and 1300C. The degree of orientation of alumina in the nanocomposite was examined on the basis of the X-ray diffraction patterns and scanning electron micrographs. It is confirmed that aluminaoriented nanocomposites were fabricated. The three-point bending strength at room temperature was observed for the nanocomposites.
        96.
        2006.04 구독 인증기관·개인회원 무료
        We have demonstrated that textured nanocomposites can be fabricated by slip casting followed by partial oxidation - reaction sintering of mixed suspensions of and SiC powders in a high magnetic field. The sintered density was changed by the degree of oxidation at 1200C and 1300C. The degree of orientation of alumina in the nanocomposite was examined on the basis of the X-ray diffraction patterns and scanning electron micrographs. It is confirmed that alumina-oriented nanocomposites were fabricated. The three-point bending strength at room temperature was observed for the nanocomposites.
        100.
        2004.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We use simulations of large-scale structure formation to study the build-up of magnetic fields (MFs) in the intergalactic medium. Our basic assumption is that cosmological MFs grow in a magnetohy-drodynamical (MHD) amplification process driven by structure formation out of a magnetic seed field present at high redshift. This approach is motivated by previous simulations of the MFs in galaxy clusters which, under the same hypothesis that we adopt here, succeeded in reproducing Faraday rotation measurements (RMs) in clusters of galaxies. Our ACDM initial conditions for the dark matter density fluctuations have been statistically constrained by the observed large-scale density field within a sphere of 110 Mpc around the Milky Way, based on the IRAS 1.2-Jy all-sky redshift survey. As a result, the positions and masses of prominent galaxy clusters in our simulation coincide closely with their real counterparts in the Local Universe. We find excellent agreement between RMs of our simulated galaxy clusters and observational data. The improved numerical resolution of our simulations compared to previous work also allows us to study the MF in large-scale filaments, sheets and voids. By tracing the propagation of ultra high energy (UHE) protons in the simulated MF we construct full-sky maps of expected deflection angles of protons with arrival energies E = 1020 eV and 4 X 1019 eV, respectively. Accounting only for the structures within 110 Mpc, we find that strong deflections are only produced if UHE protons cross galaxy clusters. The total area on the sky covered by these structures is however very small. Over still larger distances, multiple crossings of sheets and filaments may give rise to noticeable deflections over a significant fraction of the sky; the exact amount and angular distribution depends on the model adopted for the magnetic seed field. Based on our results we argue that over a large fraction of the sky the deflections are likely to remain smaller than the present experimental angular sensitivity. Therefore, we conclude that forthcoming air shower experiments should be able to locate sources of UHE protons and shed more light on the nature of cosmological MFs.
        4,000원
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