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        검색결과 819

        506.
        2009.10 구독 인증기관·개인회원 무료
        The most effective methods against pine wilt disease (Bursaphelenchus xylophilus, PWD), black pine bast scale (Matsucoccus thunbergianae), pine needle gall midge (Thecodiplosis japonensis) is the trunk injection of insecticides. The period of trunk injection that was considered with ecology and physiology of pests such as pine wilt disease, black pine bast scale and pine needle gall midge, was applied from Dec. to next Feb. and June, Dec. respectively. And there are differences in quantities of being injected chemicals to pine trees by the period of trunk injection. Thus, we investigated to prevent the effect of insecticides, to estimate the effect under the trunk injection of insecticides for pine trees against pests by the injecting period and time, boring site, opening and shutting of injection site. On Pinuns thunbergii, it was examined to figure out the effect of insecticides by the injecting period, twice a month on a sunny day around 10 AM from January to September. Injecting of insecticides was tested at a dose of 5ml per cm dbh of a pine tree after boring with hand drill at 50 cm high from the ground. As a result, abmectin 1.8% EC and phospamidon 50% SL were injected over 90% of mortalities from the end of January to the middle of March but as time goes by, injecting insecticides tended to decrease. To compare the volume of injecting insecticides in a day, between 10 AM and 2 PM on February 23rd, abamectin 1.8% EC was injected at a dose of 5ml per pine trees with micro pipette after boring with a drill machine at 50 cm high from the ground. As a result, injecting insecticide of a pine which was injected around 10 AM was completely injected and about 90% of the insecticide was injected in case of a pine that was injected around 2 PM. Trunk injection of insecticides was examined to figure out differences of the volume of injected insecticides before and after rain. There was no difference not only the rainfall but also the bored direction.
        507.
        2009.10 구독 인증기관·개인회원 무료
        Trunk injection of nematicides is applied to prevent pine wilt disease(PWD). Although the trunk injection of nematicides is effective to PWD prevention, it is not effective to vector insects such as adults of M. alternatus and M. saltuarius. Thus, This study was investigated for the insecticidal activity and the effect of feeding deterrence by injecting to pine trees with acetamiprid. For screening effective nematicides, some insecticides were injected to pines on December 30th, 2008 and their insecticidal activities and feeding areas of M. alternatus and M. saltuarius were investigated in the insects breeding dishes (100× 40mm) where put on 1 to 2-year-old twig which was selected from injected pine trees in early June. As a result, insecticidal activity and feeding deterrence of acetamicprid were most effective. Feeding areas of M. alterantus adults, when tested with 1-year-old twig and 2-year-old twig of healthy pine trees, were 170.3±107.0 mm2 and 258.0±123.2 mm2 respectively. And Feeding areas of M. alterantus adults, when tested with 1-year-old twig and 2-year-old twig of pines injected at a dose of 0.3 ml per cm dbh of a pine tree with acetamiprid, were 57.7±72.3 mm2 and 65.7±51.2 mm2 respectively and their mortalities also were 0%, 28.6%. The feeding areas of M. alterantus adults tested with 1-year-old twig and 2-year-old twig of pine trees injected at a dose of 0.6 ml per cm dbh of a pine tree with acetamiprid, were not fed on it and the mortalities were 28.0%, 57.1% respectively. In case of the feeding areas of M. saltuarius adults, when tested with 1-year-old twig and 2-year-old twig of healthy pine trees, it was 112.±35.1 mm2 and 159.2±65.2 mm2 respectively. And the feeding areas of M. saltuarius adults, when tested with 1-year-old twig and 2-year-old twig of injected pine trees at a dose of 0.3 ml per cm dbh of a pine tree with acetamiprid were 0.61±0.0 mm2 and 8.1±12.4 mm2 and both mortalities were 23.1%. Although M. saltuarius adults, when tested with 1-year-old twig of a pine tree injected at a dose of 0.6 ml per cm dbh of a pine tree with acetamiprid, were not fed on it but M. saltuarius adults tested with 2-year-old twig of the same pine tree were 2.0±3.7 mm2 and their mortalities were 53.8%, 61.5% respectively. We investigated insecticidal activities, the effects of feeding deterrence of acetamiprid for vector insects where fed twigs of injected pines by stop up hole with a cork or not, and the trunk injection to pine trees at a dose of 0.5, 1 ㎖ per ㎝ dbh of a pine tree with acetamiprid on the early June. As a result, all of the vector insects were not fed and the feeding area was within 11 ㎟ and the mortality of M. alternatus was 70%.
        508.
        2009.10 구독 인증기관·개인회원 무료
        An outbreak of Ussur Brown Katydid, Paratlanticus ussuriensis, occurred in the orchard areas of central Korea during 2006 and 2007. These crickets occur widely in Korea but before 2000 they were not regarded as an agricultural pest and were mainly confined to wooded hillsides. In an attempt to understand this katydid ecology, firstly, we have conducted a life cycle study of the Ussur brown katydid. This katydid spends one or two years as an egg stage. Most of eggs enter the initial diapause, which take place in stage 4. Less than 10% eggs didn't occur the initial diapause and developed until in stage 23 before beginning winter season. In the laboratory experiment, diapause depends on the initial temperature after eggs laid. They had an initial and final diapause around less 25℃. Therefore, it takes two years to hatch at low temperature. On the other hand, eggs are kept at temperatures around over 27℃, entry into the first diapause stage was circumvented and eggs emerged the following spring. That is, the high temperature seems to affect on the life cycle of Katydid. Thus, if they are exposed to high temperature on early egg stage, they emerge next year just after spending a winter.
        511.
        2009.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Freshwater green algae are one of the important sources of bioenergy in the future. Spirogyra is a conjugating filamentous zygnematacean green algal genus that is widely distributed worldwide with more than 400 species. Despite its widespread occurrence throughout the world, cytological studies of the genus have been limited. We investigated karyological features and chromosome numbers for seven Korean Spirogyra species. Most of the species examined in the present study showed significant karyological features, inner organization of nucleolus, heavily stainable nucleolar substance and the diffuse-centric nature of chromosomes, typical of the Conjugales. Chromosome number ranged from n=12 in S. varians to n=38 in S. africana. Aberrant cytokinesis resulted in binucleate and tetranucleate cells, which sometimes provide cytological explanation for different morphology and ploidal changes in clonal culture of Spirogyra or even different cells within the same filament. The present chromosome data also substantiates the earlier held assumption that aneuploidy must have been the chief driving force for speciation and evolution of the genus Spirogyra.
        4,000원
        515.
        2009.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study is focused on the synthesis of urea and amide derivatives particularly, since the amide moiety is an essential binding group at the binding site. Urea derivatives 3-7 and 13-14 were obtained by reaction of 2-aminopyrimidines and other amines with diverse isocyanates in pyridine as a solvent under reflux. The urea derivatives were obtained in low yield because of the highly electron deficient nature of the amino group of the 2-aminopyrimidine. Amide derivatives 8-10 were obtained in moderate yields by reaction of compound 1 with aryl chloride derivatives. Also, arylamine 11 was synthesized by Buchwald-Hartwig amination in moderate yields. Most of the compound did not show good activity against A375P melanoma cells, compared with Sorafenib as control compound.
        4,000원
        516.
        2008.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A group of new N,N-bis(5-acetylpyridin-2-yl)phenylamine derivatives was synthesized in good yield applying an optimized Buchwald-Hartwig amination protocol. The synthesized compounds showed UV absorption maxima in the range of 320-360 nm, and showed good luminescence at dilute concentrations in the blue region of the spectra (in the range of 480-497 nm). They showed also a bathochromic shift associating the increase in solvent polarity. The synthesized compounds could be investigated for use in OLEDs or as potential monomers for PLEDs.
        4,000원
        517.
        2008.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the present study, fast isothermal stabilization processes for rayon precursor fabrics were performed at 350℃ and 400℃ within 3 minutes and the chemical and physical characteristics of the stabilized fabrics were investigated. In addition, rayon precursor fabrics were pre-treated with three different phosphorous-based flame retardants and then stabilized. The effect of flame retardants on the chemical composition, thermal shrinkage, weight change, thermal stability and XRD results was examined, comparing with those of the precursor fabrics. The result showed that the stabilization of rayon fabrics was most effective as the stabilization temperature was 350℃, the stabilization time was 3 min, and the pre-treatment with phosphoric acid of 1 vol%. The carbon contents of stabilized rayon fabrics were increased with increasing stabilization temperature and time, whereas the oxygen contents were decreased. Also, it is likely that the pre-treatment with phosphoric acid plays a role in retarding the change of chemical structure of rayon fabric. The XRD result was quite consistent with the result showing the effect of phosphoric acid on the chemical composition, thermal shrinkage and weight reduction of rayon fabric.
        4,000원