• Bulletin of the Korean Chemical Society
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• 제34권12호
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• pp.3690-3694
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• 2013

The $H_2Ge=Ge:$ and its derivatives ($X_2Ge=Ge:$, X = H, Me, F, Cl, Br, Ph, Ar${\ldots}{\ldots}$) is a new species. Its cycloaddition reactions is a new area for the study of germylene chemistry. The mechanism of the cycloaddition reaction between singlet state Cl2Ge=Ge: and formaldehyde has been investigated with CCSD(T)//MP2/$6-31G^*$ method. From the potential energy profile, it could be predicted that the reaction has only one dominant reaction pathway. The reaction rule presented is that the two reactants first form a fourmembered Ge-heterocyclic ring germylene through the [2+2] cycloaddition reaction. Because of the 4p unoccupied orbital of Ge: atom in the four-membered Ge-heterocyclic ring germylene and the ${\pi}$ orbital of formaldehyde forming a ${\pi}{\rightarrow}p$ donor-acceptor bond, the four-membered Ge-heterocyclic ring germylene further combines with formaldehyde to form an intermediate. Because the Ge: atom in intermediate hybridizes to an $sp^3$ hybrid orbital after transition state, then, intermediate isomerizes to a spiro-Ge-heterocyclic ring compound via a transition state. The research result indicates the laws of cycloaddition reaction between $H_2Ge=Ge:$ and formaldehyde, and laid the theory foundation of the cycloaddition reaction between $H_2Ge=Ge:$ and its derivatives ($X_2Ge=Ge:$, X = H, Me, F, Cl, Br, Ph, Ar${\ldots}{\ldots}$) and asymmetric ${\pi}$-bonded compounds, which is significant for the synthesis of small-ring and spiro-Ge-heterocyclic compounds. The study extends research area and enriches the research content of germylene chemistry.

• 한국환경과학회지
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• 제24권9호
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• pp.1101-1121
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• 2015

The seasonal variation of phytoplankton communities and its standing crops in accordance with environmental factors were investigated at Yeongrang-ho, Cheongcho-ho, Mae-ho and Hyang-ho which are located in the East coast of Korea during April to October 2011. High concentrations of T-N and T-P were observed in four lagoons due to the inflowing nutrients from farmlands and residential areas near lagoons. Nutrient salts mainly composed of nitrogen and phosphate caused the eutrophication of the lakes, leading to the robust growth of phytoplankton. During the period of investigation, 64 to 107 taxa of phytoplankton were observed in four lagoons. Diatoms were the most dominant species with high density. Non-point pollution source was estimated as the main cause of water pollution of lagoons. Trophic states of lagoons evaluated using the value of TSI and TSIKO indicated that all the investigated lagoons were in the eutrophication state.

• 한국환경과학회지
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• 제17권9호
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• pp.949-956
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• 2008

The data of temperature, chlorophyll a, phytoplankton and NOAA/AVHRR satellite data were analyzed about 7 stations around Wando Island area on August 30, 2005. The sea water temperature range was from $15.19^{\circ}C$ to $24.97^{\circ}C$, and there was a cold water mass from the station 1 to 5 around the outside of Chungsando Island, the water temperature was lower at the bottom than surface. The salinity was $32.41{\sim}34.03$, DO was $7.40{\sim}9.14mg/L$, but the concentration of chlorophyll a was 1ug/L higher at the bottom than surface. Total phytoplankton appeared from the whole stations were 47 genus, 80 species and diatoms were dominant. A lot of dinoflagellates Ceratium forca and diatoms Thalassithrix spp. mostly appeared in the cold water mass were turned up from the station 1 to 5. 4 groups of phytoplankton clusters were shown in the surface, and 3 groups of phytoplankton clusters were shown at the bottom according to the water temperature. On the ground of the result analyzed with NOAA/AVHRR satellite data, the SST around Wando Island was $22{\sim}25^{\circ}C$, it was formed by thermohaline front latitudinally

• 한국환경과학회지
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• 제18권1호
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• pp.21-32
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• 2009

The short-term variations of the mesozooplankton community structure were investigated in Gamak Bay during summer season, 2006. The study was based on a comprehensive survey constituting from 12 stations on June 19, July 28, August 4, and August 29, respectively. Mean of temperature and chlorophyll ${\alpha}$ concentrations in the surface layer were significantly higher than those in bottom layer, and those concentrations were significantly higher in the inner bay than those in the outer bay. A total of 40 taxa including 19 copepods were observed in Gamak Bay during summer season. Mean abundance of total mesozooplankton varied from 1,859 to 26,111 indiv. $m^{-3}$. The dominant species were Noctiluca scintillans, Penilia avirostris, Evadne tergestina, Paracalanus parvus s. 1., Acartia omorii and Cirriped nauplii and cyprii in Gamak Bay, and they contributed 90% of mean abundance of total mesozooplankton. Noctiluca scintillans was high after the rainfall. Cluster analysis showed that the mesozooplankton community could be divided into 4 distinct groups, indicating rapid change of the community in the short-term of this survey. The relative contribution of each group of the N. scintillans, P. avirostris, E. tergestina, and P. parvus s. 1. showed differences during the phytoplankton bloom period. The mesozooplankton community compositions were highly associated with water temperature, and salinity in physical conditions, and food organisms affect short-term variations in mesozooplankton composition. Interestingly, protozoa N. scintillans, and Cladocera appeared to be one of the key organisms to extinguish the phytoplankton bloom. Therefore, this study suggests that N. scintillans, and Cladocera could be a key player to control the mesozooplankton community structure during summer season, 2006.

• 한국환경보건학회지
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• 제31권5호
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• pp.387-397
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• 2005

In oder to understand the deposition possibility of water-soluble inorganic ions in the atmospheric fine particulates for the human respiratory tract, the mass size distribution of ion species was measured using an Anderson sampler in the Iksan during fall, 2004. Samples were analyzed for major water-soluble ions using Dionex DX-100 ion chromatograph. The size distribution of water-soluble inorganic ions in the atmospheric particulates appeared bimodal distribution, which were divided around $1-2{\mu}m$ into two groups. Mass site distribution of total ion in the coarse mode was found to be almost similar level during the sampling period, but fluctuations of mass size distribution in the fine mode were observed. Considering the mass size distribution of total ion concentrations for the respiratory deposition region, it was found that about 77.1% of total tons could be deposited in the alveolar region, and which dominated the daily variation of total ion concentrations. The concentration of total ions, which could be deposited in both the head region and the tracheobronchial region, was $3.95{\mu}g/m^3$, whereas that in the alveolar rerion was $13.28{\mu}g/m^3$. Dominant ions which could be deposited in the alveolar region were ${NO_3}{^-},\;{SO_4}^{2-}\;and\;{NH_4{^+}$, accounting for about 40%, 27% and 22% of the total ions, respectively. Although $K^+$ was approximately 3% of total ions, it was shown that most of this could be deposited in the alveolar region due to its high fraction of small size distribution originated from anthropogenic source of biomass burning. The presence of these ions in the fine mode may be of public health significance as they are very biologically harmful to health and have a high probability of being deposited in human lung tissue.

• 한국어류학회지
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• 제29권1호
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• pp.80-86
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• 2017

본 연구는 남해 중부 연안역에서 2016년 4~8월까지 자어군집구조의 월 변화를 조사하였다. 조사기간 동안 총 42종의 자어가 출현하였다. 우점종 중 멸치(E. japonicus)는 여름보다는 봄철에 우점하였고, 용서대(C. abbreviates)는 봄철에만 출현하였으며 수조기(N. albiflora)는 여름철에만 출현하였다. 자어 군집은 계절별로 4~5월 (봄)과 6~8월 (여름)의 그룹으로 유의하게 나눌 수 있었고, 여름철은 또다시 6~7월과 8월의 두개의 유의한 그룹으로 나눌 수 있었다. 2016년 8월 조사해역에서는 이상 고수온 현상이 발생하여 표면수온이 $28^{\circ}C$까지 상승하였고, 멸치와 수조기 자어의 출현량은 산란 적정수온을 넘은 수온으로 인해 급감하였다.

• 한국응용곤충학회지
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• 제19권2호
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• pp.109-112
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• 1980

본답후기인 8중-9상순에 걸쳐 끝동매미충 난에 기생하는 기생봉의 종류와 이들의 기생율을 남부 4개 지역에서 재래품종과 통일계통 품종 포장에서 조사한 결과는 다음과 같다. 1. 난에 기생하는 실적으로 Gonatocerus sp. 2종과 Paracentrobia andoi 그리고 Anagrus sp. 1종 등 모두 4종의 난기생봉이 분포하고 있음이 밝혀졌다. 2. 기생율 조사 결과 Gonatocerus sp.의 평균 난괴기생율과 난립기생율은 각각 $58.8\%$와 $41.0\%$였고 Paracentrobia andoi의 경우에는 각각 $6.2\%$와 $5.3\%$로서 Gonatocerus sp.가 Paracentrobia andoi의 기생율 보다 훨씬 높안 우점종을 이루어 있었으며 이들 두 종이 같은 난괴에 혼재하는 율은 $5.4\%$였다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.139-139
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• 2017

The complete chloroplast genome sequence of Avena sterilis L., a dominant wild oat species in the family Poaceae, is first reported in this study. The complete cp genome sequence of A. sterilis is 135,887 bp in length with 38.5% overall GC content and exhibits a typical quadripartite structure comprising one pair of inverted repeats (21, 603 bp) separated by a small single-copy region (12,575 bp) and a large single-copy region (80,106). The A. sterilis cp genome encodes 111 unique genes, 76 of which are protein-coding genes, 4 rRNA genes, 30 tRNA genes and 18 duplicated genes in the inverted repeat region. Nine genes contain one or two introns. Pair-wise alignments of cp genome were performed for genome-wide comparison. This newly determined cp genome sequence of A. sterilis will provide valuable information for the future breeding programs of valuable cereal crops in the family Poaceae.

• 환경생물
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• 제22권1호
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• pp.75-82
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• 2004

2000년부터 2002년까지 통영 바다목장 해역 5개 정점표층수와 저층수에서 종속영양세균의 개체수를 평판계수법으로 측정하여 종속영양세균군집의 계절별 변동추이를 비교 분석하고, 우점종을 선별하여 동정하였다. 7월과 8월의 하절기에 채수한 해수에는 봄 혹은 가을 및 겨울에 채수한 해수에 비하여 모든 정점에서 훨씬 더 많은 종속영양세균이 검출되었다. 저층수에 비하여 표층수에서 종속영양세균의 수가 더 많았으나 동절기(2001년 12월과 2002년 2월)에는 해수 온도가 낮으며 해수의 대류가 느려짐에 따라 부유물질이 저층에 축적되는 관계로 저층수의 종속영양세균의 수가 표층수의 경우 보다 오히려 더 많이 검출되었다 해수 내 종속영양세균의 수와 태풍의 빈도는 뚜렷한 상관관계를 보이지 않아 태풍의 빈도 이외에 태풍의 진로와 강도 및 태풍을 수반하는 집중 호우와 해수의 온도 변화가 종속영양세균의 수에 영향을 미치는 것으로 판단되었다. 통영 바다목장 해역의 종속영양세균의 우점종은 Pseudomonas fluorescens, Pseudomonas stutzeri, Acinetobucter lwoffii 및 Sphingomonas paucimobilis로 동정되었다.

• Journal of the Korean Wood Science and Technology
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• 제43권5호
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• pp.566-577
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• 2015

White Jabon (Anthocephalus cadamba Miq.) is one of the fast growing species in Indonesia and has the potential as the raw material for pulp and paper. In this research, 3, 5, and 7 years old White Jabon woods were pulped under different active alkali charge of 15%, 18%, 21%, 24%, and 27%, and its effect on delignification degree, kappa number, pulp yield, pulp viscosity, brightness, unbeaten freeness, and delignification selectivity was investigated. The results showed that tree age and active alkali concentration influenced the quality of pulp and pulping properties, except for that of unbeaten freeness. Delignification degree increased with increasing active alkali charge, and this brought about the decrease of pulp kappa number. The pulping yield tended to decrease below the Klason lignin of approximately 4%. Even though the 3 years old wood resulted in the highest brightness and highest delignification selectivity, the highest pulp viscosity was obtained with the 5 years old wood. The dominant fiber length of all wood ages was in the range of 1.2 - 2.0 mm. The 3 years old wood was considered to be the most promising raw material for kraft pulping in the view point of pulping properties, pulp quality and harvesting rotation.