• Applied Microscopy
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• 제24권2호
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• pp.105-114
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• 1994

Maize dwarf mosaic virus (MDMV) strain A에 감염된 수수 (Sorghum bicolor L. Moench) 품종 HOK와 strain B에 감염된 Pioneer 8680의 엽세포를 미세구조적으로 비교연구한 결과 종단면과 횡단면으로 초박절편된 표본에서 다양한 원통형 봉입체의 형성이 관찰되었다. MDMV strain A와 B는 세포질 내에 존재하는 특별한 봉입체의 유무에 따라 뚜렷이 구별되었다. MDMV-B에 감염된 Pioneer 8680 수수 엽세포는 pinwheels, bundles, scrolls, 그리고 laminated aggregates 형태의 원통형 봉입체가 관찰된 반면, MDMV-A에 감염된 HOK 수수 엽세포에서는 laminated aggregates가 결여되어 있다. 특히 laminated aggregates의 유무와 관련하여 MDMV 두 strain간에 원통형 봉입체의 미세구조적 차이점은 potyvirus군을 아군으로 분류하는 형태학적 지표가 되어왔다. laminated aggregates가 존재하면 아군 III으로, 존재하지 않을 경우 아군 I로 분류될 수 있다. 이런 원통형 봉입체의 이형화는 바이러스 특이적 유도체로서, 아마도 감염의 발전에 따른 형태 발생을 발현하는 것으로 사료된다.

• 식물병연구
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• 제12권1호
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• pp.25-27
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• 2006

벼오갈병바이러스(Rice dwarf virus, RDV)는 Phytoreovius 속에 속하며 게놈은 double stranded RNA의 12분절로 이루어져 있는데 전기영동상에서 크기가 큰 것부터 S1에서 S12로 명명한다. 본 실험에서는 RDV 입자 및 P12 단백질의 세포질 내에서의 소재양식을 확인하였다. 바이러스 입자 및 P12 단백질 특이적 항혈청에 protein A-gold 입자를 immunolabelling하여 전자현미경에서 gold입자의 존재양상을 관찰하였다. 바이러스 입자 특이적 항혈청을 사용한 경우에는 gold 입자가 세포질내의 바이러스 입자에 특이적으로 반응한 것이 관찰되었다. P12단백질 특이적 항혈청의 경우 gold 입자가 세포질내의 세포소기관에 특이적으로 존재하지 않고 세포질전체에 산재하여 존재하였다. 이 결과로서 RDV S12가 코드하는 단백질 P12가 세포질내에 존재함을 확인하였다.

• 식물병연구
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• 제12권1호
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• pp.62-64
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• 2006

2005년 7월 전북고창 지역에서 옥수수에 줄무늬 위축증상을 나타내는 이병주를 채집하여 게놈 dsRNA 분리 및 RT-PCR 반응을 실시하였다. 게놈 dsRNA 분리는 이병엽 100mg에서 직접 dsRNA를 추출하여 agarose gel에서 전기영동 하였으며, 10개의 분절을 확인하였다. 추출한 dsRNA를 주형으로 하여 S7, S8, S10 full-length 특이적인 primer를 제작하여 RT-PCR을 실시하였다. 그 결과 각각의 분절에서 예상되는 크기의 밴드를 확인하였다. 고창지역의 사료용 옥수수 재배지에서 RBSDV의 발생면적은 약 22ha에 달하였으며 발생이 심한 곳은 약 80%의 이병율을 나타내기도 하였다.

• 한국잠사곤충학회지
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• 제13권1호
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• pp.17-22
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• 1971

1968년부터 1970년까지 뽕나무위축병에 관하여 접목전염 및 곤충매개전염시험을 한바 결과를 요약하면 다음과 같다. 1. 병근에 건전수목을 절접하므로서 활착주수중 30%의 전염율을 나타냈다. 건전근에 병수목을 절접함에 있어서는 병수목을 월동전에 채취 저장하였다가 익춘 공시한 것은 활착주수중 14%가 전염되였는데 반하여 월동후에 채취한 병수목에 있어서는 전혀 발병되지 않았다. 건전대목에 병수목을 절접하여 불활착된 것 중 대아가 발조한 것은 전혀 발병되지 않았다. 2. 뽕나무위축병의 무병지대에서 채집한 마름무늬매 미충을 중증위축병주에서 7일, 14일, 21일 간식 각각흡즙시킨 성충을 무병실생묘에 방사접종한 결과 7일구는 전염되지 않았으며 14일구는 22％, 21일구는 61％ 전염율을 나타냈다. 흡즙시간과 접종시간은 길수록 전염율이 높았다.

• 천문학회지
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• 제48권2호
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• pp.105-112
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• 2015

The symbiotic star V1016 Cygni, a detached binary system consisting of a hot white dwarf and a mass-losing Mira variable, shows very broad emission features at around 6825 Å and 7082 Å, which are Raman scattered O vi λλ 1032, 1038 by atomic hydrogen. In the high resolution spectrum of V1016 Cyg obtained with the Bohyunsan Optical Echelle Spectrograph these broad features exhibit double peak profiles with the red peak stronger than the blue counterpart. However, their profiles differ in such a way that the blue peak of the 7082 feature is relatively weaker than the 6825 counterpart when the two Raman features are normalized to exhibit an equal red peak strength in the Doppler factor space. Assuming that an accretion flow around the white dwarf is responsible for the double peak profiles, we attribute this disparity in the profiles to the local variation of the flux ratio of O vi λλ 1032, 1038 in the accretion flow. A Monte Carlo technique is adopted to provide emissivity maps showing the local emissivity of O vi λ1032 and O vi λ1038 in the vicinity of the white dwarf. We also present a map indicating the differing flux ratios of O vi λλ 1032 and 1038. Our result shows that the flux ratio reaches its maximum of 2 in the emission region responsible for the central trough of the Raman feature and that the flux ratio in the inner red emission region is almost 1. The blue emission region and the outer red emission region exhibit an intermediate ratio around 1.5. We conclude that the disparity in the profiles of the two Raman O vi features strongly implies accretion flow around the white dwarf, which is azimuthally asymmetric.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2009년도 한국우주과학회보 제18권2호
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• pp.35.3-36
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• 2009

To investigate properties of the stellar contents of the resolved asymptotic giant branch stars in the nearby dwarf galaxies, we obtained wide-field JHKs images of the dwarf irregular galaxies NGC 6822, IC 1613 and the dwarf elliptical galaxy NGC 205, using the WIRCam near-infrared imager of the CFHT. The obtained (J-Ks, Ks) and (H-Ks, Ks) color-magnitude diagrams for the resolved stars in the galaxies contain populations of foreground stars, super giant stars, red giant stars and the asymptotic giant branch (AGB) stars. Using corollary photometric data in the visible bands, AGB stars were selected in the color-magnitude diagrams with a wide wavelength baseline in color indices. In color-color diagrams of the resolved AGB stars, we identified C stars from M giant stars for each galaxies, i.e., 726 C stars in NGC 6822, 126 C stars in IC 1613 and 593 C stars in NGC 205. The number ratios of C stars to M-giants were estimated to be $0.59\pm0.03$ in NGC 6822, $0.30\pm0.03$ in IC 1613 and $0.14\pm0.01$ in NGC 205. From analyses of the correlations of the spatial distribution of the C/M ratios with the HI properties and dynamical structures of the target galaxies, we discuss environmental effects of the star formation in the galaxies. We also discuss the epochs of the AGB star formation in the galaxies by comparing theoretical isochrones with the color distributions and luminosity functions of the AGB stars.

• 천문학회보
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• 제37권2호
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• pp.68.1-68.1
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• 2012

We present a comprehensive study of the stellar populations in two faint M31 dwarf satellites, And XI and And XIII. Using deep archival images from the Wide Field Planetary Camera 2 (WFPC2) onboard the Hubble Space Telepscope (HST), we characterize the horizontal branch (HB) morphologies and the RR Lyrae (RRL) populations of these two faint dwarf satellites. Our new template light curve fitting routine (RRFIT) detected RRL populations from both galaxies. The mean periods of $RR_{ab}$ (RR0) stars in And XI and And XIII are < $P_{ab}$ > = $0.621{\pm}0.040$, and < $P_{ab}$ > = $0.648{\pm}0.038$ respectively. Even though the RRL populations show a lack of $RR_{ab}$ stars with high amplitudes (Amp(V) > 1.0 mag) and relatively short periods ($P_{ab}$ ~ 0.5 days), their period - V band amplitude (P-Amp(V)) relations track the lower part of the general P-Amp(V) trend in the M31 outer halo RRL populations. The metallicities of $RR_{ab}$ stars were calculated via the [Fe/H]-log $P_{ab}$-Amp(V) relationship of Alcock et al. The metallicities thus obtained ($[Fe/H]_{And}$ $_{XI}=-1.75%$; $[Fe/H]_{And}$ $_{XIII}=-1.74$) are consistent with the values calculated from the RGB slope indicating that our measurements are not significantly affected by the evolutionary effects of RRL stars. We discuss the origins of And XI and And XIII based on a comparative analysis of the luminosity-metallicity (L-M) relation of Local Group dwarf galaxies.

• 한국환경복원기술학회지
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• 제23권4호
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• pp.59-67
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• 2020

In this study, the effects of windbreak fences composed of natural vegetation on one-year-old seedlings were analyzed to develop restoration methods for an endangered subalpine species, the dwarf Siberian pine (Pinus pumila (Pall.) Regel). One-year-old seedlings were planted in 2016 by sowing seeds that had been collected from the Daecheongbong area on Mt. Seoraksan, South Korea, in 2014. The area near Daecheongbong was selected as the experimental site, and treatment and control plots (2m×2m) were installed at the site. To analyze the effects of wind protection, windbreak fences were constructed in the treatment plots using hairy Korean rhododendrons (Rhododendron mucronulatum Turcz. var. ciliatum Nakai) from the surrounding area and weather stations were installed to investigate atmospheric temperature, humidity, and wind speed. In all control plots without windbreak fences, dwarf Siberian pine seedlings were killed by strong winds seven months after planting. In contrast, the average survival rate of the seedlings in treatment plots was 96.7% after seven months, 64.2% after two years, and 45% after three years, with most (85.3%) of the seedlings showing good initial root establishment. Accordingly, windbreak fences composed of natural vegetation are suitable for promoting the early establishment of seedlings in the restoration of dwarf Siberian pine stands.

• Journal of Astronomy and Space Sciences
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• 제4권1호
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• pp.11-23
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• 1987

외신성의 폭발 원인을 반성으로부터 accretion disk에 흘러들어온 물질유입량의 갑작스런 증가로 가정하였다. 따라서 $\alpha$-disk모델에서 source term을 100배로 증가시켜 Newton-Raphson 방법으로 풀었다. 구해진 disk의 물리적 변수들을 disk의 반경에 대해 나타냈으며, 시간에 따른 disk의 광도와 질량 변화를 구하였다. $\alpha$ 의 값을 각각 0.1, 0.12, 0.15, 0.18로 바꿔가며 유입되는 물질의 양이 일정할 때와 disk의 밝기가 가장 밝을 때의 변수들을 비교하였다. 이들 결과를 $1M_\bigodot$의 항성의 표면과 대기와 비교하였다.

• 천문학논총
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• 제27권4호
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• pp.183-184
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• 2012

We present the latest results from the Mission Program NIRLT, the NIR spectroscopic observations of brown dwarfs using the IRC on board AKARI. The near-infrared spectra in the wavelength range between 2.5 and $5.0{\mu}m$ is especially important to study the brown dwarf atmospheres because of the presence of non-blended bands of major molecules, including $CH_4$ at $3.3{\mu}m$, $CO_2$ at $4.2{\mu}m$, CO at $4.6{\mu}m$ and $H_2O$ around $2.7{\mu}m$. Our observations were carried out in the grism-mode resulting in a spectral resolution of ~ 120. In total, 27 sources were observed and 18 good spectra were obtained. We investigate the behavior of three molecular absorption bands, CO, $CH_4$ and $CO_2$, in brown dwarf spectra relative to their spectral types. We find that the $CH_4$ band appears in the spectra of dwarfs later than L5 and CO band is seen in the spectra of all spectral types. $CO_2$ is detected in the spectra of late-L and T type dwarfs.