• 한국제4기학회지
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• 제17권2호
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• pp.63-69
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• 2003

Three tree-ring monsoon rainfall reconstructions from China and Korea have been used in this paper to investigate the variation of the East Asian summer monsoon over the past 160 years. Statistically, there is no linear correlation on a year-by-year basis between Chinese and Korean monsoon rainfall, but region-wide synchronous variation on decadal-scale was observed. Strong monsoon intervals (more rainfall) were 1860-1890, 1910-1925,1940-1960, and weak monsoon periods (dry or even drought) were 1890-1910, 1925-1940, 1960- present. Reconstructions also display that the East Asian summer monsoon suddenly changed from strong into weak around mid-1920, and the East Asian summer monsoon keeps going weak after 1960.

• 대한수학회논문집
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• 제20권2호
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• pp.275-290
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• 2005

Let $S\;=\;R[\chi_{ij}\mid1\;{\le}\;i\;{\le}\;m,\;1\;{\le}\;j\;{\le}\;n]$ be the polynomial ring over a noetherian commutative ring R and $I_p$ be the determinantal ideal generated by the $p\;\times\;p$ minors of the generic matrix $(\chi_{ij})(1{\le}P{\le}min(m,n))$. We describe a minimal free resolution of $S/I_{p}$, in the case m = n = p + 2 over $\mathbb{Z}$.

• Journal of Plant Biology
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• 제31권3호
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• pp.169-185
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• 1988

Vessel elements in lateral root, tap root, transition region, stem and mid vein of 1-year old, 3-year old and 5-year old ginseng (Panax ginseng C.A. Meyer) are studied with light microscope to clarify the distribution and differentiation of several kinds of vessel elements. Vessel elements are classified into five types such as ring vessel, spiral vessel, scalariform vessel, reticulate vessel and pitted vessel according to the secondary thickenings of cell wall. All of the five types are not observed in each organ, but diverse kinds of vessels are present in stem and mid vein compared with the underground organs such as tap root and lateral root. The length of vessel elements is longest (680$\mu$m) in stem and shortest (143$\mu$m) in tap root. The diameter of vessel elements is 19.0$\mu$m in tap root and the angle of perforation plate comes under 22$^{\circ}$-60$^{\circ}$. The degree of differentiation of vessel elements according to the length, diameter and angle of perforation plate of vessel elements is highest in tap root regardless of the age of ginseng. Three types of perforation plate such as scalariform, intermediate type of simple and scalariform, and simple perforation plate are observed. The vascular tracheids are characteristically observed in mid vein of 1-year old ginseng, and in transition region of 3 and 5-year old ginseng.

• Korean Journal of Mathematics
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• 제20권3호
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• pp.307-314
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• 2012

Let M be a left R-module and R be a ring with unity, and $S=\{0,2,3,4,{\ldots}\}$ be a submonoid. Then $M[x^{-s}]=\{a_0+a_2x^{-2}+a_3x^{-3}+{\cdots}+a_nx^{-n}{\mid}a_i{\in}M\}$ is an $R[x^s]$-module. In this paper we show some properties of $M[x^{-s}]$ as an $R[x^s]$-module. Let $f:M{\rightarrow}N$ be an R-linear map and $\overline{M}[x^{-s}]=\{a_2x^{-2}+a_3x^{-3}+{\cdots}+a_nx^{-n}{\mid}a_i{\in}M\}$ and define $N+\overline{M}[x^{-s}]=\{b_0+a_2x^{-2}+a_3x^{-3}+{\cdots}+a_nx^{-n}{\mid}b_0{\in}N,\;a_i{\in}M}$. Then $N+\overline{M}[x^{-s}]$ is an $R[x^s]$-module. We show that given a short exact sequence $0{\rightarrow}L{\rightarrow}M{\rightarrow}N{\rightarrow}0$ of R-modules, $0{\rightarrow}L{\rightarrow}M[x^{-s}]{\rightarrow}N+\overline{M}[x^{-s}]{\rightarrow}0$ is a short exact sequence of $R[x^s]$-module. Then we show $E_1+\overline{E_0}[x^{-s}]$ is not an injective left $R[x^s]$-module, in general.

• 천문학회보
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• 제36권1호
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• pp.82.2-82.2
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• 2011

Infra-Red Dark Clouds (IRDCs) seen silhouette against the bright Galactic background in mid-IR are a class of interstellar clouds that are dense and cold with very high column densities. While IRDCs are believed to be the precursors to massive stars and star clusters, individual IRDCs show diverse star forming activities within them. We report a remarkable example of such cloud, the IRDC at ${\Gamma}53.2^{\circ}$, and star formation activity in this cloud. The IRDC was previously identified in part as three separate, arcmin-size clouds in the catalogue of MSX IRDC candidates, but we found that the IRDC is associated with a long, filamentary CO cloud at 2 kpc from the Galactic Ring Survey data of $^{13}CO$ J = 1-0 emission, and that its total extent reaches ~ 30pc. The Spitzer MIPSGAL 24mm data show a number of reddened mid-IR sources distributed along the IRDC which are probably young stellar objects (YSOs), and the UWISH2 $H_2$ data (2.122mm) reveal ubiquitous out flows around them. These observations indicate that the IRDC is a site of active star formation with YSOs in various evolutionary stages. In order to investigate the nature of mid-IR sources, we have performed photometry of MIPSGAL data, and we present a catalogue of YSOs combining other available point source catalogues from optical to IR. We discuss the evolutionary stages and characteristics of YSOs from their IR colors and spectral energy distributions.

• 한국지반공학회논문집
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• 제20권6호
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• pp.5-10
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• 2004

일반적으로 일차원 압밀상태에 있는 정지토압계수 $K_0$값은 삼축시험에서 구해지지만, 압밀중의 간극수의 흐름이 방사류이고, 공시체의 변형이 3차원적이므로, 얻어진 값의 신뢰성에는 의문이 있다. 여기서는, 일차원 압밀시험기를 개량하여, 압밀링 중앙높이에 배치한 압밀링 요소를 토압감지부로 하며, 감지부 중앙에서는 간극수압을 측정하였다. 내경 6cm의 압밀링은 부동(浮動)링 형식으로 높이 4cm의 공시체 중앙높이가 항상 같은 위치를 유지하는 구조이다. 직경 6cm의 공시체와 샘플링후 시료변형을 고려한 압밀링 내경보다 직경이 약간 작은 공시체에서 얻은 압밀종료시의 $K_0$값은 공시체직경과 압밀압력에 상관없이 거의 0.5를 나타내었다.

• The Plant Pathology Journal
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• 제28권4호
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• pp.390-400
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• 2012

Eight potato-producing provinces of Iran were surveyed during the growing seasons of 2004-2006 to detect the presence of Tomato yellow fruit ring virus (TYFRV), a tentative species in the genus Tospovirus. A total of 1,957 potato leaf samples were collected from plants with tospovirus-like symptoms of chlorotic or necrotic spots, chlorosis and necrosis. The samples were tested by enzyme-linked immunosorbent assay using TYFRV-specific antibodies. Among those tested, 498 samples (25.4%) were found to be infected with the virus. The virus was detected in 72.4% of the potato fields in all provinces surveyed. Thirteen potato isolates of TYFRV were selected for further biological and molecular studies. Based on their reactions on Nicotiana tabacum plants, the isolates were separated into two groups, namely L (local infection) and N (systemic infection). The nucleotide sequences of the nucleoprotein (N) genes of the isolates were determined and compared with the homologous sequences in Genbank. No recombination evidence was found in the isolates using different recombination-detecting programs. In the phylogenetic tree, the potato isolates fell into two major groups: IRN-1 and IRN-2 corresponding to the two biologically separated groups. This study shows for the first time the biological and phylogenetic relationships of geographically distant TYFRV isolates from potatoes in the mid-Eurasian country of Iran.

• 대한공업교육학회지
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• 제35권2호
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• pp.224-237
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• 2010

수중 운동체가 가동할 때 돔 앞쪽에 설치된 센서에 유기되는 진동파 소음은 구조를 통해 전달된다. 구조를 통해 전달되는 소음과 진동이 음향 센서의 성능을 저하시키는 요인이 되지 않도록 구조물로 타고 들어오는 진동파를 효과적으로 차단하기 위하여 본 연구에서는 CRP(Carbon Reinforced Plastic)와 SNORE링(Self-NOise REduction Ring)를 설치하고 주파수에 따른 변위와 응력의 변화를 관찰하였다. 곡면 구조물의 재질은 알루미늄이며 최대 외경 530mm, 길이 215mm 정도이다. 곡면 구조물의 전면부는 직경이 270mm이며 평면형상으로 되어 있다. 주파수에 따른 CRP와 SNORE 링 부착 전후에서의 응력 감소율을 시뮬레이션 하였으며 12kHz와 15kHz 주변에서는 95% 이상의 감소율을 보였다. 음향 센서의 부착 위치에 따른 응력의 변화를 계산하였으며 중심부에서 가장 높게 나타났고 20mm, 40mm 떨어진 곳으로 이동할수록 응력의 크기가 낮게 나타났다. 본 연구의 결과는 음향센서의 감도를 높이는데 기초자료로 활용할 수 있을 것이다.

• Korean Journal of Mathematics
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• 제18권1호
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• pp.37-43
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• 2010

Let D be an integral domain, X be an indeterminate over D, and $N_v=\{f{\in}D[X]{\mid}(A_f)_v=D\}$. In this paper, we introduce the concept of t-locally divided domains, and we then prove that $D[X]_{N_v}$ is a locally divided domain if and only if D is a t-locally divided UMT-domain, if and only if D[X] is a t-locally divided domain.

• 한국가금학회지
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• 제24권3호
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• pp.107-116
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• 1997

In order to achieve optimal reproductive performance, reliable morphological and physiological basic data on the reproductive organs are desirable. Adult male Korean ring-necked pheasant in inactive(mid of January) and active state (end of April) were used in this study. In addition, five active state pheasants were received a single dose of 60Co-ray 500 rads each to damage the testes. The objective of this study was to investigate the distribution pattern of protein gene product (PGP) 9.5 and ${\alpha}$-tubulin in the pheasant testes of the active, inactive and ${\gamma}$-ray irradiated active states. The results obtained were summarized as follows 1. The seminiferous tubules collected in inactive states( mid of Jan) showed narrow lumen, and the spermatogonia and the Sertoli cell were well preserved. The PGP 9.5 immunoreactivity of these tubules showed a positive reaction in paranucleus area of the spermatogonia, and a positive reaction in a small number of the Leydig cells in the interstitium of the seminiferous tubules. 2. The seminiferous tubules were dilated in active state(end of April) as compared with the inactive state. The PGP 9.5 reactivity in these tubules showed a positive reaction in many Leydig cells in the interstitium of the seminiferous tubules, and the testes of ${\gamma}$-ray irradiated group showed partially weak reaction in the interstitium of the seminiferous tubules. 3. The ${\alpha}$-tubulin reactivity in the seminiferous tubules of the inactive testes was strongly positive in the cytoplasmic process of the Sertoli cell from the basal stem region to the apical ex-tension. From the broad part of the stem region to the luminal space, the active testes showed a strong positive reaction. The ${\gamma}$-ray irradiated groups showed diminished reaction in the basal region.