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        검색결과 650

        303.
        2008.05 구독 인증기관·개인회원 무료
        신나몬 속에서 추출한 식물체 정유 6종의 고구마뿌리혹선충(Meloidogyne incognita) 유충(J2)에 대한 살선충력을 9개 농도(ppm) 수준에서 24웰플레이트를 이용하여 실내검정 하였다. 그 결과 카시아오일류(cassia oils)에서 높은 살선충력이 확인되었는데, 그 중 가장 강한 활성을 보인 cassia oil의 구성 성분들을 GC-MS로 분석하였다. 이 오일에 함유된 주요 성분들은 (E)-cinnamaldehyde, benzaldehyde, α-terpenen, ρ-cymene, limonene, linalool, α-terpineol, cinnamyl alcohol, eugenol, salicylaldehyde, α-copaene, (E)-cinnamic acid, cinnamyl acetate, β-caryophyllene 등이었다. 각 성분들의 살선충력을 조사하였는데, (E)-cinnamaldehyde가 15 ppm과 10 ppm 농도에서도 99%와 57%의 살선충력을 보였다. 그래서 이것과 유사한 구조를 갖고 있는 화합물들 42종을 대상으로 200, 100, 50, 25, 10 ppm 농도에서 구조에 따른 살선충력을 비교 검정하였는데, vinyl cinnamate와 (E)-methoxcycinnamaldehyde가 10 ppm에서 각각 83%와 44%의 살선충력을 나타냈다. 이는 살선충력을 갖는 화합물들이 기본 골격으로서 C6-C3를 필요로 하고 더불어 방향성을 갖는 알킨(alkene) 또는 알데하이드 그룹을 갖고 있어야 함을 알 수 있었다. 이상의 실내실험을 통해 신나몬 속 식물체 정유들 또는 함유 화합물들이 토양 내 뿌리혹선충을 방제할 수 있는 잠재성이 매우 높은 식물군임을 확인하였다.
        310.
        2007.09 구독 인증기관 무료, 개인회원 유료
        3,000원
        311.
        2007.09 구독 인증기관 무료, 개인회원 유료
        4,000원
        316.
        2007.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This experiment was conducted to investigate population dynamics of white grubs and its damages in sweet potato fields. There were three species of white grubs that fed on the roots of sweet potato in Honam area. Among them, Holotrichia parallela was a major insect pest. Damage rate of sweet potato by white grubs were about 2 to 40% differed with regions. In some region where it was severe the damage rate of sweet potato was about 80% or more. H. parallela overwintered as a late 3rd instar larvae in soil from late October to late-June, and the survival rate of them was 92%. The occurrence pattern of H. parallela larvae varied in different seasons. In sweet potato field, H. parallela larvae populations started being observed during late-July to mid.-August. The damage by the grub began to occur late-August in field and lasted to the harvest time.
        3,000원
        317.
        2007.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was carried out to determine occurrence and damage of golden apple snail, Pomacea canaliculata on water seeding area in Jeonnam province. The density of golden apple snail maintained high until October 2003, but quickly decreased from November. They overwintered only in a portion of the water canals but could not find in dried paddy field. They reproduced from May and June in the canal water and paddy field, respectively. Feeding time of golden apple snail on rice seedlings was 235.2 seconds, feeding length of that was 8.4 ㎝. When golden apple snail fed rice seedlings, the stem remain only 2.5 ㎝ from areal part which could not recover. The more density of golden apple snail, the faster feeding rate. Density and number of eggs laid of golden apple snail after overwintering was higher on bank around of paddy field than on middle of that. The percent of shell size after over wintering was higher in small (below 25 ㎜) than big (over 36 ㎜). But in case of Boseong area, the size was reverse because the soil has soft mud. The survival rate of overwintering golden apple snail was lower than that of breeding. They did not move when the temperature changed rapidly, but the temperature increased they start to move. They dead almost below -3℃. The damage of rice by golden apple snail in the direct water seeding was 20%. In machine transplanting, rice damaged only fore-end of leaf and recovered subsequently. When golden apple snail release in direct water seeding field, the percent of damage was 5.6% in immediately release plot. The later release, the lower damage.
        4,000원
        319.
        2006.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        6,300원
        320.
        2006.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Nanostructured metallic materials are synthesized by bottom-up processing which starts with powders for assembling bulk materials or top-down processing starting with a bulk solid. A representative bottom-up and top-down paths for bulk nanostructured/ultrafine grained metallic materials are powder consolidation and severe plastic deformation (SPD) methods, respectively. In this study, the bottom-up powder and top-down SPD approaches were combined in order to achieve both full density and grain refinement without grain growth, which were considered as a bottle neck of the bottom-up method using conventional powder metallurgy of compaction and sintering. For the powder consolidation, equal channel angular pressing (ECAP), one of the most promising method in SPD, was used. The ECAP processing associated with stress developments was investigated. ECAP for powder consolidation were numerically analyzed using the finite element method (FEM) in conjunction with pressure and shear stress.
        4,000원