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        검색결과 198

        121.
        2008.05 구독 인증기관·개인회원 무료
        The mason bee (Osmia cornifrons Radoszkowsky) is an excellent pollinator of apple. To understand geographic genetic variation of the species and relationships among populations sequenced a portion of mitochondrial COI gene, which corresponds to “DNA Barcode” region (658 bp) from 81 individuals collected over eight localities in Korea. The sequence data were used to investigate genetic diversity within populations and species, geographic variation within species, phylogeographic relationship among populations, and phylogenetic relationship among haplotypes. Summarized, overall moderate to low genetic diversity within populations and species was characteristic, concordant with the high potential to disperse of O. cornifrons in Korea. Although two populations were genetically subdivided from the remaining localities, no clear regional bias was observed. Overall, high rate of gene flow among localities and low FST was characteristic considering other relevant studies that investigated population genetic structure of other insects occurring in Korean peninsula.
        122.
        2008.05 구독 인증기관·개인회원 무료
        To understand geographic genetic variation of the species and relationships among populations of the bumble bee, Bombus ardens, we sequenced a portion of mitochondrial COI gene, which corresponds to "DNA Barcode" region (658 bp) from 101 B. ardens individuals collected over 11 localities in Korea. The sequence data were used to investigate genetic diversity within populations and species, geographic variation within species, phylogeographic relationship among populations, and phylogenetic relationship among haplotypes. A total of nine haplortpes were found, but they very close to each other (a maximum sequence divergence of 0. 304%). Summarized, overall moderate to low genetic diversity within populations and species was characteristic, concordant with the high potential to disperse of B. ardens in Korea. There was no clear regional subdivision was observed and relatively high rate of gene flow among localities and low FST was characteristic.
        123.
        2008.05 구독 인증기관·개인회원 무료
        The turnip aphid is a worldwide pest, damaging mainly to crucifers. In order to understand the life parameters of Lipaphis erysimi for the eventual goal of control, the developmental periods, survival rates, lifespan, and fecundity of the species were investigated under five temperature regimes (15℃ - 35℃). Furthermore, the efficacy of several environment-friendly agricultural materials (EFAMs) that are on the market was subjected to test in order to obtain further accurate information. The developmental period of the turnip aphid nymph was longest at 15ºC as 16.9 days, shortened as temperature goes up to 25ºC (5.4 days), and then somewhat increased at 30ºC (5.9 days), suggesting that the most efficient temperature for nymphal development could be around 25ºC. Mortality of the nymphal turnip aphid was obvious at 35ºC, whereas it was minimal at other temperature schemes. The longevity of adults shortened as temperature goes up to 30ºC. In particular, the maximum lifespan for adults continued for 55 days at 15ºC, but shortened to 21 days at 30ºC. The total fecundity per day was 35.7 at 15ºC, 81 at 20ºC, 64.2 at 25ºC, and 6.6 individuals at 30ºC, showing the highest fecundity at 20ºC. After the turnip aphids were successfully stabilized in indoor environment the insecticidal activity was tested and mortality was determined 12, 24, 36, and 48 hrs after EFAMs are treated. Several on-the-market EFAMs showed more than 90% of insecticidal activity within 24 hrs or 48 hrs, but a few showed less than 90% activity, signifying importance of selection of proper EFAMs.
        126.
        2005.06 구독 인증기관 무료, 개인회원 유료
        Cloned calves derived from somatic cell nuclear transfer (SCNT) have been frequently lost by sudden death at 1 to 3 month following healthy birth. To address whether placental anomalies are responsible for the sudden death of cloned calves, we compared protein patterns of 2 placentae derived from SCNT of Korean Native calves died suddenly at two months after birth and those of 2 normal placentae obtained from AI fetuses. Placental proteins were separated using 2-Dimensional gel electrophoresis. Approximately 800 spots were detected in placental 2-D gel stained with coomassie-blue. Then, image analysis of Malanie III (Swiss Institute for Bioinformatics) was performed to detect variations in protein spots between normal and SCNT placentae. In the comparison of normal and SCNT samples, 8 spots were identified to be up-regulated proteins and 24 spots to be down-regulated proteins in SCNT placentae, among which proteins were high mobility group protein HMG1, apolipoprotein A-1 precursor, bactenecin 1, tropomyosin beta chain, H+-transporting ATPase, carbonic anhydrase II, peroxiredoxin 2, tyrosine-rich acidic matrix protein, serum albumin precursor and cathepsin D. These results suggested that the sudden death of cloned calves might be related to abnormal protein expression in placenta.
        4,000원
        132.
        2004.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        사용후핵연료 금속전환체의 저장 안정성을 높이기 위해 금속전환체의 주성분인 금속우라늄과 산화 안정화물질로 알려져 있는 Nb을 첨가하여 모의 금속전환체 합금을 제작하였다. 모의 금속전환체 합금을 온도구간에서 순수 산소분위기로 산화시험을 수행하고 무게증가를 열중량 분석기(TGA)로 측정하였다. 산화 실험결과 U-Nb 모의 금속전환체는 순수 금속우라늄에 비하여 상당한 산화 저항성을 가졌다. U-Nb 합금의 경우 Nb의 함량 에 따라 각각 온도가 일 경우에는 1.61, 7.78, 11.76, 20.14배 , 에서 1.45, 5.98, 10.08, 11.15배, 에서 1.33, 4.82, 8.87, 6.84배 순수 금속우라늄에 비해 산화저항성이 향상되는 것으로 나타났다. 또한 Nb 합금에 대한 활성화에너지는 kcal/mol 로 나타났다.
        4,000원
        136.
        2003.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Pt-Ru/Carbon as an anode catalyst supported on the commercial activated carbon (AC) having high surface area and micropore was characterized for application of Direct Methanol Fuel Cell (DMFC). The Pt-Ru/AC anode catalyst used in this experiment showed the performance of 600 mA/cm2 current density at 0.3 V. The borohydride reduction process using NaBH4, denoted as a process A, showed much higher current and power densities than process B prepared by changing the reduction and washing process of process A. The particle sizes are strongly affected by the reduction process than the specific surface area of raw active carbon and the sizes are almost constant when the specific surface area of carbon are over than the 1200 m2/g. Smaller particle size of catalyst and more narrow intercrystalite distance increased the performance of DMFC.
        4,000원
        138.
        2001.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Composite adsorbents were prepared by mixing water plant sludge with phenolic resin having the ratio of 1 : 1, 1 : 2, and 1 : 3 respectively, curing from 100℃ to 170℃ under N2 atmosphere, and then activating with N2 at 700℃. Thermal property, specific surface area and morphology of the composite adsorbents as well as their precursors were measured by TGA, BET and SEM respectively. Removal efficiency of the composite adsorbents to NH4+ and TOC was compared with those of commercial zeolite and activated carbon. The adsorbents presented very promising TOC removal efficiency of 98%, which was identical level to that of commercial activated carbon while they displayed removal efficiency, only 32%, of NH4+. Therefore, this composite adsorbent considered as the alternative material of commercial activated carbon, used as an expensive removal agent of organic substances and THM in water treatment plant and it also suggested a possibility of practical application in other processes.
        3,000원
        139.
        1999.10 구독 인증기관·개인회원 무료
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