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        검색결과 10

        1.
        2008.10 구독 인증기관·개인회원 무료
        Neoseiulus womersleyi (Schicha) (Acari: Phytoseiidae) is one of the most important predators of spider mites in Japan. Various characteristics have been studied in this species. However, because there is a lack of genetic markers, genetic diversity within and among populations has not been well elucidated. Microsatellites, short stretches of tandem-repeated 1- to 5- nucleotide sequences, are ubiquitously present in eukaryotic genomes and are highly polymorphic. Their high polymorphism makes them suitable markers for studying intra-specific variation. In this study, we developed microsatellite markers in N. womersleyi, and then examined genetic diversity in their populations. Microsatellite enriched genomic DNA library was contracted and sequenced from a single female adult. Of the 40 plasmids sequenced, 31 plasmids showed microsatellite sequences and 24 plasmids were unique. Finally, we could design primers on three loci. When tested their diversity on one wild and two laboratory populations, five to 18 alleles were detected. The wild population showed highest genetic diversity, and this divergence decreased in rearing populations. To investigate the effects of different rearing conditions, genetic diversity in two rearing populations, which were different in population size, were compared with those in the original wild populations. The allelic richness and gene diversity were not significantly different between wild and large-size populations, while the values were significantly decreased in small-size populations. Thus, 40 to 60 females per generation was sufficient to conserve the genetic diversity in N. womersleyi populations during laboratory rearing. In conclusion, the microsatellite markers developed were useful to evaluate genetic diversity in wild and laboratory populations of N. womersleyi.
        3.
        2006.09 구독 인증기관·개인회원 무료
        We reported a P/M soft magnetic material with core loss value of , which is lower than that of 0.35mm-thick laminated material, by using high purity gas-atomized iron powder. Lack of mechanical strength and high cost of powder production are significant issues for industrial use. In order to achieve both low core loss and high strength by using inexpencive powder, the improvement of powder shape and surface morphology and binder strength was conducted. As the result, the material based on water-atomized powder with 80 MPa of TRS and 108 W/kg of core loss (W10/1k) was achieved.
        4.
        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.
        5.
        2001.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        LaMnO3, and gel films were deposited by spin-coating technique on scandium-doped zirconia (YSZ) substrate using the precursor solution prepared from , or ,2-methoxyethanol, and polyethylene glycol. By heat-treating the gel films, the electrochemical cells, were fabricated. The effect of polyethylene glycol on the microstructure evolution of and thin films was investigated, and NOx decomposition characteristics of the electrochemical cells were investigated at to . By applying a direct current to the electrochemical cell, good NOx conversion rate could be obtained relatively at low current value even if excess oxygen is included in the reaction gas mixture.
        4,000원
        6.
        1996.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this paper several advantage of RO/NF technologies have been described. However, it should be noted that membrane technology does not solve all the water treatment problems encountered in municipalities. Membranes can provide effective and highly optimized solutions when integrated with conventional technologies such as coagulation, sand filtration, and activated carbon treatments.
        4,000원
        8.
        2007.04 KCI 등재 서비스 종료(열람 제한)
        The sonolytic decomposition of NHCs(Nitrogen Heterocyclic Compounds), such as atrazine[6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine], simazine(6-chloro-N,N'-diethyl-1,3,5-triazine-2,4-diamine), trietazine(6-chloro-N,N,N'-triethyl-1,3, 5-triazine-2,4-diamine), in water was investigated at a ultrasound frequency of 200kHz with an acoustic intensity of 200W under argon and air atmospheres. The concentration of NHCs decreased with irradiation, indicating pseudo-first-order kinetics. The rates were in the range 1.06∼2.07(×10−2min−1) under air and 1.30∼2.59(×10−2min−1) under argon at a concentration of 200μM of NHCs. The rate of hydroxyl radicals(∙OH) formation from water is 19.8μMmin−1 under argon and 14.7μMmin−1 under air in the same sonolysis conditions. The sonolysis of NHCs is effectively inhibited, but not completely, by the addition of t-BuOH(2-methyl-2-propanol), which is known to be an efficient ∙OH radical scavenger in aqueous sonolysis. This suggests that the main decomposition of NHCs proceeds via reaction with ∙OH radical; a thermal reaction also occurs, although its contribution is small. The addition of appropriate amounts of Fenton's reagent [Fe2+] accelerates the decomposition. This is probably due to the regeneration of ∙OH radicals from hydrogen peroxide, which would be formed from recombination of ∙OH radicals and which may contribute a little to the decomposition.
        9.
        2004.02 KCI 등재 서비스 종료(열람 제한)
        A aqueous solution of malodorants (i.e., n-valeraldehyde, n-valeric- acid, 2-methylisoborneol, and trimethylamine) was exposed to 200kHz ultrasound with a power of 6.0W/cm2 per unit volume in a sonochemical reactor under room temperature and atmospheric pressure condition. The concentration of malodorants decreased with irradiation time, indicating pseudo-first-order kinetics. The removal efficiency of malodorants was about from 50% to 96% decomposed after 90 minutes sonication. At the deodorization, it was determined by triangle odor bag(TOB) method for odor sensory measurement, and it indicated that over 60% of relative odors were deodorized with degradation by the sonication.