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        검색결과 99

        41.
        2019.04 구독 인증기관·개인회원 무료
        뽕나무깍지벌레는 복숭아, 매실, 뽕나무 등 31종의 기주식물을 가해하는 기주범위가 광범위한 난방제 해충으로 알려져 있다. 2017년도에 뽕나무깍지벌레는 5월 상순부터 부화를 시작하여 암컷성충 1마리가 75.5개(47~159개)의 알을 낳으며 모든 알이 부화하는데 약 19일이 소요되었고, 부화율은 약 87%였다. 반면에 2018년도에는 4월 하순부터 부화를 시작하여 암컷성충 1마리가 49.4개(12~71개)의 알을 낳으며 모든 알이 부화하는데 13일이 소요되었으며, 부화율은 약 72%를 보였다. 부화한 약충들은 이동 후 5월 중순부터 고착약충으로 되고, 6월 중순부터 2세대 성충이 활동하기 시작하였다. 부화약충기에 약제를 살포하여 살충효과를 조사한 결과, 살충률이 100%인 반면에, 고착약충기 에는 살충율은 2.7%로 살충효과가 낮은 것을 확인하였다.
        46.
        2018.10 구독 인증기관·개인회원 무료
        The citrus flatid planthopper, Metcalfa pruinosa is one of the invasive insect species in South Korea. M. pruinosa is a broad polyphage damaging over 200 plant species including ginseng, although there is a difference in preference. We selected six insecticides that showed high mortality in ginseng field such as emamectin benzoate EC, sulfoxaflor SG, etofenprox EW, cypermethrin EC, thiacloprid SC and pyrifluquinazon SG. In addition, a method to attract and kill M. pruinosa by treating pesticides on attractive plants (e.g., corn, perilla) with high preference was also tested. The control effect varied from 10 to 80% depending on the distance between forest and farmland. These methods can be used for the control of M. pruinosa in the ginseng farm when the PLS (Positive List System) is fully implemented in 2019.
        48.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The microstructure, flexural properties, electrical conductivity, thermal conductivity and electromagnetic interference (EMI) shielding effectiveness (SE) of epoxy composites filled with multi-walled carbon nanotubes (CNTs), exfoliated graphite nanoplatelets (xGnPs) and CNT-xGnP hybrid filler were investigated. The EMI SE of the CNT-xGnP hybrid composite was higher than 25 dB at 100 MHz while that of the xGnP based composite was almost zero. The flexural modulus of the CNT-xGnP based epoxy composite continuously increased to 3.32 GPa with combined filler content up to 10 wt% while that of the CNT based epoxy composites slightly decreased to 1.96 GPa at 4 wt% CNT, and dropped to 1.57 GPa at 5 wt% loading, which is lower than that of epoxy. The CNT and CNT-xGnP samples had the same EMI SE at the same surface resistivity, because samples with the same surface conductivity have the same amount of the charge carriers.
        4,000원
        49.
        2017.04 구독 인증기관·개인회원 무료
        The nesting behavior, reproduction, fruit set and shape of O. cornifrons varied significantly with the released sex ratio of O. cornifrons. A female : male sex ratio of 1 : 2 was resulted in a 3.4 to 6.7 fold higher than other sex ratio in a nesting behavior. A ratio of 1 : 2 resulted in a 1.2-fold nesting rate, which was slightly higher than other nesting rates. Releasing only males resulted in a 2.4-fold greater amount of fruit set in non-pollinated sites. A sex ratio of 1 : 2 gave a slightly higher shape index and a 1.2 to 1.6-fold lower asymmetric index than other sex ratios. There was no significant difference between female release numbers in fruit set, and 100 to 200 females gave a slightly higher shape index than 400 females. Thus, we determined that 200 females should be released per 2,000㎡ and that the sex ratio of females to males should be 1 : 2.
        51.
        2015.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Multi-walled carbon nanotube (MWCNT)/polycarbonate (PC) nanocomposite was prepared by direct melt mixing to investigate the effect of the shear rate on the surface resistivity of the nanocomposites. In this study, an experiment was carried out to observe the shear induced orientation of the MWCNT in the polymer matrix using a very simple melt flow indexer with various loads. The compression-molded, should be eliminated. MWCNT/PC nanocomposite sample exhibited lower percolation thresholds (at 0.8 vol%) and higher electrical conductivity values than those of samples extruded by capillary and injection molding. Shear induced orientation of MWCNT was observed via scanning electron microscopy, in the direction of flow in a PC matrix during the extrusion process. The surface resistivity rose with increasing shear rate, because of the breakdown of the network junctions between MWCNTs. For real applications such as injection molding and the extrusion process, the amount of the MWCNT in the composite should be carefully selected to adjust the electrical conductivity.
        4,000원
        52.
        2014.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Germplasm collection of lily in the mountainousarea is laborious and time consuming accompanied withhigh costs and high risk due to inappropriate environmentalconditions. Cryopreservation being an ideal method for thelong-term preservation can be employed in conservation ofvaluable lily germplasm. Previously, we developed cryo-preservation protocol for Lilium germplasm using ‘dropletvitrification’. In this paper, we have chosen shoot tips as amaterial for cryopreservation because of their genetic safetyupon regrowth in tissue culture. Using this protocol, wehave preserved approximately 160 accessions of lily germ-plasm in 2010~2012. The regeneration rates are rangedfrom 54.3% to 58.5% while the survival rates were from58.3% to 66.4%. Among Lilium germplasm cryopreserved,there are some Korean, Chinese, and Taiwanese seedstocks which have good qualities for inter-species hybrid.Moreover, we also conserved Korean wild endangered seedstock, especially Lilium hansonii. The morphological studyof Lilium germplasm regenerated from cryopreserved mate-rial confirmed the stability of clonal material following cryo-preservation. We anticipate this cryo-collection will beavailable and useful to curators or breeders of Lilium andthis cryobank will also facilitate the conservation and inter-national exchange of Lilium germplasm.
        4,000원
        55.
        2013.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A cell formation approach based on cluster analysis is developed for the configuration of manufacturing cells. Cell formation, which is to group machines and parts into machine cells and the associated part families, is implemented to add the flexibility and efficiency to manufacturing systems. In order to develop an efficient clustering procedure, this paper proposes a cluster analysis-based approach developed by incorporating and modifying two cluster analysis methods, a hierarchical clustering and a non-hierarchical clustering method. The objective of the proposed approach is to minimize intercellular movements and maximize the machine utilization within clusters. The proposed approach is tested on the cell formation problems and is compared with other well-known methodologies available in the literature. The result shows that the proposed approach is efficient enough to yield a good quality solution no matter what the difficulty of data sets is, ill or well-structured.
        4,300원
        59.
        2009.10 구독 인증기관·개인회원 무료
        Deformed wing virus (DWV) of honeybees (Apis mellifera) is closely associated with characteristic wing deformities, abdominal bloating, paralysis, and rapid mortality of emerging adult bees. Here, we report for the first time the occurrence of DWV-infected bumble bees (Bombus terrestris). For the present study, the detection of DWV virus from the adult bumble bee, death adult bumble bee, mail bumble bee, pupa and larva to the infection cycle was investigated in the same colony. Using specific RT-PCR protocols for the detection of DWV followed by sequencing of the PCR products we could demonstrate that the bumble bees were indeed infected with DWV. The virus was detected from diseased insects, and its partial DWV gene was cloned and sequenced. The partial DWV gene encoding the polyprotein is 711-nt of 235 amino acid residues. The deduced nucleotide sequence of the polyprotein partial gene of DWV showed 96.9%, 96.2%, 96.8%, and 96.5% homology to other structure polyprotein partial gene of DWV, respectively. Phylogenetic analysis further conformed that the deduced nucleotide sequence of the polyprotein partial gene of DWV divided to the outside tree. We describe the first time that presence of Deformed wing virus(DWV) from bumble bee(Bombus terrestris) in korea using RT-PCR.
        60.
        2009.10 구독 인증기관·개인회원 무료
        We report for the first time the occurrence of DWV-infected bumble bees (Bombus ignitus). For the present study, the detection of DWV virus from the female and male bumble bee was investigated in the same colony. The Deformed wing virus (DWV) of honeybee (Apis mellifera) is closely associated with characteristic wing deformities, abdominal bloating, paralysis, and rapid mortality of emerging adult bees. Using specific RT-PCR protocols for the detection of DWV followed by sequencing of the PCR products we could demonstrate that the bumble bees were indeed infected with DWV. The virus was detected from Bombus ignitus, and its partial DWV gene was cloned and sequenced. The partial DWV gene encoding the polyprotein is 711-nt of 235 amino acid residues. The deduced nucleotide sequence of the polyprotein partial gene of DWV showed 96.9%, 96.2%, 96.8%, and 96.5% homology to other structure polyprotein partial gene of DWV from insects, respectively. Phylogenetic analysis further conformed that the deduced nucleotide sequence of the polyprotein partial gene of DWV divided to the outside tree. We describe the first time that presence of Deformed wing virus(DWV) from bumble bee(Bombus terrestris) in korea using RT-PCR.
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