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        검색결과 1,657

        576.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We demonstrated an effective way of preparing melt spinnable mesophase pitches via catalytic hydrogenation of petroleum residue (fluidized catalytic cracking-decant oil) and their subsequent thermal soaking. The mesophase pitches thus obtained were analyzed in terms of their viscosity, elemental composition, solubility, molecular weight, softening point and optical texture. We found that zeolite-induced catalytic hydrogenation under high hydrogen pressure contributed to a large variation in the properties of the pitches. As the hydrogen pressure increased, the C/H ratio decreased, and the solubility in n-hexane increased. The mesophase pitch with entirely anisotropic domains of flow texture exhibited good meltspinnability. The mesophase carbon fibers obtained from the catalytically hydrogenated petroleum residue showed moderate mechanical properties.
        4,000원
        577.
        2017.10 구독 인증기관·개인회원 무료
        The entomopathogenic fungus Metarhizium anisopliae is one of potent biological control agents against a variety ofinsect pests. In this study, we investigated enzyme production of M. anisopliae strains A and B. They produced extracellularenzymes for degrading the epidermis of Monochamus alternatus, a crucial mediator of the pinewood nematode Bursaphelenchusxylophilus. With Q-TOF MS/MS analysis, 29 kDa protein, a major band on a SDS-PAGE gel, was identified as subtilisin-likeserine protease PR1A. M. anisopliae A produced an extracellular enzyme more efficiently than M. anisopliae B: however,enzyme activities targeted for the cuticle were comparable. Our results suggest that the two strains of M. anisopliae havethe biological potential against M. alternatus with insecticidal protease production.
        578.
        2017.10 구독 인증기관·개인회원 무료
        The entomopathogenic fungus Metarhizium anisopliae B is a powerful biological control agent against Monochamusalternatus, a crucial mediator of the pinewood nematode Bursaphelenchus xylophilus. In this study, production of destruxins(dtxs), insecticidal cyclic hexadepsipeptides, was monitored in the submerged culture of M. anisopliae B. Three typesof dtxs, i.e., destruxin A, B, and E, were produced during the culture. Among the three dtxs, the production yield ofdestruxin A was best, followed by destruxin B and E. Destruxin A production was increased when pH was controlledat 6.0, whereas production of destruxin E was not affected by the pH control. The highest yield of dtxs A, B, and Ewere 16.4, 7.3, and 6.1 mg L-1, respectively. Considering that process for dtxs production has not been optimized, M.anisopliae B has more powerful implication as a biocontrol agent.
        579.
        2017.10 구독 인증기관·개인회원 무료
        Potato tuber moth (PTM) is damaging pest of solanaceous crop invasive to Korea. We showed earlier that it inflicteddamage to tomato. So in this study, we evaluated accessions of Solanum lycopersicum (Money maker, Campari, AilsaCraig, LA3475 and e6203) and a wild variety of S. pimpinellifolium for resistance variability. A day old larvae of PTMwere inoculated to leaves and fruits. The result showed high survivability on leaves of Ailsa Craig (95.6%±4.4 SE) andlow on fruits of S. pimpinellifolium (14.0%±6.0). Leaves of LA3475 and fruits of S. pimpinellifolium were less preferred.Volatile compounds could be the cause. Density of trichomes could also influence PTM activity on leaves. These resultsgive us information on resistance variability which could be utilized if there is a host shift due to climate change.
        580.
        2017.10 구독 인증기관·개인회원 무료
        The potato tuber moth, Phthorimaea operculella (Zeller), is a ubiquitous pest on potatoes, tobacco, tomato and othercrops. The small hive beetle (SHB), Aethina tumida Murray, is a pest of European honeybees (Apis mellifera L.) in severalcountries in the world. Propolis is a balm-like substance collected from plants by bees. Its chemical composition variesand depends mainly on the flora in the region in which it is collected as well as the bee species. Hitherto biologicalproperties and the chemical composition of the essential oil extracted from propolis of Korean origin are unknown. Inthis study, while searching for an environmentally friendly method to control these pests we evaluated the repellent effectsof essential oil of propolis collected from Bee Lab of Andong National University and found that it possess repellentactivity against both small hive beetle and potato tuber moth. Moreover, a total of 171 constituents of the oil were identifiedof which 6 were major compounds using GC/MS analysis. We also compared the chemical composition of this oil withthose from 2 Ethiopian regions.