• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2010년도 한국우주과학회보 제19권1호
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• pp.34.4-34.4
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• 2010

We present the properties of globular cluster systems for 10 early-type galaxies in low density environments obtained using deep images from the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope (HST). Using the ACS Virgo Cluster Survey as a counterpart in high-density environments, we investigate the role of environment in determining the properties of their globular cluster systems. We detect a strong colour bimodality of globular cluster systems in half of our galaxy sample. It is found that there is a strong correlation between the colour and richness of globular cluster populations and their host galaxy luminosities: the less bright galaxies possess bluer and fewer globular clusters as also seen in rich cluster environments. However, the mean colour of globular clusters in our field sample are slightly bluer than those in cluster environments at a given galaxy luminosity, and the colour of the red population has a steeper slope with absolute luminosity. By employing the YEPS simple stellar population model, the colour offset corresponds to metallicity difference of $\Delta$[F e/H ] ~ 0.15 - 1.20 or an age difference of $\Delta$age ~ 2 Gyr on average, implying that GCs in field galaxies appear to be either less metal-rich or younger than those in cluster galaxies. Although we have found that galaxy environment has a subtle effect on the formation and metal enrichment of GC systems, host galaxy mass is the primary factor that determines the stellar populations of GCs and the galaxy itself.

• Journal of Ecology and Environment
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• 제35권4호
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• pp.359-365
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• 2012

We investigated leaf disease intensity of Kalopanax septemlobus (prickly castor oil tree) caused by the parasitic fungus Mycosphaerella acanthopanacis, in thirty natural host populations in the Japanese Archipelago. The disease intensity observed for individual trees were analyzed using a generalized additive model as a function of tree size, tree density, climatic terms and spatial trend surface. Individual tree size and conspecific tree density were shown to have significant negative and positive effects on disease intensity, respectively. The findings suggest that the probability of disease infection is partly determined by dispersal of infection agents (ascospores) from the fallen leaves on the ground, which can be enhanced by aggregation of host trees in a forest stand. Regional-scale spatial bias was also present in disease intensity; the populations in northern Japan and southern Kyushu were more severely infected by the fungus than those in southwestern Honshu and Shikoku. Regional variation of disease intensity was explained by both climatic factors and a trend surface term, with a latitudinal cline detected, which increases towards the north. Further research should be conducted in order to understand all of the factors generating the latitudinal cline detected in this study.

• 한국응용곤충학회지
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• 제46권2호
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• pp.221-227
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• 2007

2004년부터 2005년까지 호남지방의 쌀 생산조정지를 중심으로 노린재류의 발생과 기주식물을 조사하였다. 노린재류는 총 8과 26종이 조사되었으며, 중산간지인 무안에서 시골가시허리노린재의 발생이 가장 많았고, 발생최성기는 7 월이었다. 평야지인 완주는 2004 년에는 전반적으로 노린재류의 발생량이 적었고, 2005 년에는 시골가시허리노린재 발생최성기는 7월과 8월이었다. 쌀 생산조정지에서 인근 벼 포장으로 이동하는 시기는 시골가시허리노린재 등 5종은 8월, 우리가시허리노린재 등 3종은 9월이었다. 또한, 쌀 생산조정지에서 잡초를 섭식하는 노린재 종류는 시골가시허리노린재, 우리가시허리노린재, 북쪽비 단노린재, 더듬이긴노린재, 빨강촉각장님노린재, 메추리노린재, 가시점둥글노린재, 풀색노린재였다.

• Applied Microscopy
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• 제11권1호
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• pp.29-38
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• 1981

Bacteriophage f2 were treated with ozone at various concentrations for 20 minutes. The inactivation kinetics of f2 phage were examined during ozonation. In order to study the mode of action of ozone on the phage f2, absorption of the phage to the host pili was meassured by utilyzing radioactivity of tritium incorporated into the phage RNA. Sucrose density gradient analysis and electron microscopy were also used to prove the mechanism of ozone inactivation of the phage. Strucural proteins of the phage were broken by ozonation into many protein subunits. The extent of phage breakage was proportional to ozone concentration and reaction time. Percent decrease of the phage absorption to the host pili was coincident with the rate of ozone inactivation of the phage. Ozone inactivation of bacteriophage f2 was shown to be caused by the breakage of the structural protein and blockage of the phage absorption to the host pili.

• Mycobiology
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• 제28권3호
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• pp.115-118
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• 2000

To determine the degree of variability among the host plant species in their abilities to become colonized by arbuscular mycorrhizal fungi (AMF), the inoculum for AMF was collected from the various sites in Korea and was inoculated to the three horticultural plants; Tagetes patula, Torenia fournieri, and Salvia splendens. After 4-month growth under greenhouse, mycorrhizal root colonization rates and spore density were measured. The roots of T. patula showed higher colonization rate than both plants of T. fournieri and Salvia splendens. The mycorrhizal root colonization was influenced by both of the AM fungal inoculum and the host species or their interactions. The combination of the host and fungal species was suggested to be important for the application of AMF to horticultural crops.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.346-349
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• 2009

We investigated the doping effects of $ReO_3$ in different p-type organic semiconductors on the formation of charge transfer complexes and the electrical conductivity by comparing the absorption in ultraviolet-visible-nearinfrared (UV-Vis-NIR) and the current density-voltage characteristics of the hole only devices, respectively. The large energy difference between the HOMO level of host and Fermi energy level of dopant (${\Delta}E$=$E_{HOHO,host}$ - $E_{F,dopant}$) gives higher concentration of CT complexes and enhanced conductivity.

• Parasites, Hosts and Diseases
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• 제24권2호
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• pp.194-200
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• 1986

1986년 5월부터 동년 10월까지 폐흡충 침윤지로 알려진 경북 울진군을 관류하는 남대천, 광천, 왕피천에서 가재의 분포상을 조사한 다음 가재에서의 폐흡충 피낭유충 기생상을 조사하였다. 가재의 서식밀도는 한사람이 한시간에 잡을수 있는 가재의 평균수로 표시하였으며, 이번 조사에서는 최소 1마리, 최고 13마리, 평균 4마리를 채집 할 수 있었다. 가재에서의 폐흡충 피낭유충 검출률은 총 피검가재 817마리중 127마리 (15.5%)였으며, 지역별로는 두천계곡에서 25.1%로 가장 높았다. 가재 체부위별 검출상은 감염가재 127마리에서 총 219개의 피낭유충을 검출하였으며, 이중 두흉부(60.7%), 아가미(37.4%), 간(1.8%)순으로 검출 할 수 있었으며, 감염가재 1마리당 평균 유출수는 1.7개 이었다. 이상의 성적으로 미루어 보아 경북 울진군 남대천, 광천, 왕피천 유역은 아직도 폐흡충 침윤지로 남아 있음을 알았다.

• 한국응용곤충학회지
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• 제45권3호
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• pp.375-380
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• 2006

프루텔고치벌(Cotesia plutellae)은 단독형 내부기생봉으로 배추좀나방(Plutella xylostella)을 기주로 생활한다. 이 기생봉이 배추좀나방을 탐색하고 기주의 발육상태 및 다른 생리 상태를 인식하는데 촉각은 매우 중요한 감각기관으로 작용할 것으로 주목 받아왔다. 본 연구는 이 기생봉의 촉각 구조를 주사전자현미경으로 관찰하고, 관찰된 감각기 종류와 밀도를 바탕으로 기생생리를 이해하고자 수행되었다. 촉각 전체 길이에서 암수간 차이가 없으며 모두 16개 편절마디를 가지고 있다. 감각기 구조는 크게 긴털형감각기, 센털형감각기 그리고 판상감각기로 나누어 밀도조사를 실시하였고, 대부분 감각기는 편절에 집중적으로 분포했다. 이 가운데 긴털형감각기가 암수 모두 약 87%를 차지하였다. 편절에서 긴틸형감각기와 판상감각기는 말단 부위에서 밀도가 감소하는 반면, 센털형감각기는 말단 부위로 갈수록 증가하여, 암컷의 경우 9번째 편절 마디 이후로 급격하게 밀도 증가를 보였다. 촉각 부위별 제거에 따른 기생에 미치는 효과를 분석한 결과 편절 후반부를 제거하면 기생능력을 완전히 상실하고, 말단 4개 편절 마디를 제거해도 불과 30% 이하의 낮은 기생율을 기록했다. 이상의 결과는 프루텔고치벌의 기생에 촉각의 중요성을 보여주었으며, 특히 센털형감각기가 기주 탐색에 밀접히 관여될 가능성을 제시하였다.

• Bulletin of the Korean Chemical Society
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• 제32권6호
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• pp.1851-1858
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• 2011

Details of the double-bond isomerization of 1-hexene over H-ZSM-5 were clarified using density functional theory. It is found that the reaction proceeds by a mechanism which involves the Br${\o}$nsted acid part of the zeolite solely. According to this mechanism, 1-hexene is first physically adsorbed on the acidic site, and then, the acidic proton transfers to one carbon atom of the double bond, while the other carbon atom of the double bond bonds with the Br${\o}$nsted host oxygen, yielding a stable alkoxy intermediate. Thereafter, the Br${\o}$nsted host oxygen abstracts a hydrogen atom from the $C_6H_{13}$ fragment and the C-O bond is broken, restoring the acidic site and yielding trans-2-hexene. The calculated activation barrier is 12.65 kcal/mol, which is in good agreement with the experimental value. These results well explain the energetic aspects during the course of double-bond isomerization and extend the understanding of the nature of the zeolite active sites.

• 천문학회보
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• 제46권1호
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• pp.53.2-53.2
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• 2021

Quasar luminosity function (QLF) shows the active galactic nucleus (AGN) demography as a result of the combination of the growth and the evolution of black holes, galaxies, and dark matter halos along the cosmic time. The recent wide and deep surveys have improved the census of high-redshift quasars, making it possible to construct reliable ultraviolet (UV) QLFs at 2 < z < 6 down to M1450 = -23 mag. By parameterizing these up-to-date observed UV QLFs that are the most extensive in both luminosity and survey area coverage at a given redshift, we show that the UV QLF has a universal shape, and their evolution can be approximated by a pure density evolution (PDE). In order to explain the observed QLF, we construct a model QLF employing the halo mass function, a number of empirical scaling relations, and the Eddington ratio distribution. We also include the outshining of AGN over its host galaxy, which made it possible to reproduce a moderately flat shape of the faint end of the observed QLF (slope of ~ -1.1). This model successfully explains the observed PDE behavior of UV QLF at z > 2, meaning that the QLF evolution at high redshift can be understood under the framework of halo mass function evolution. The importance of the outshining effect in our model also implies that there could be a hidden population of faint AGNs (M1450 > -24 mag), which are buried under their host galaxy light.