• The Korean Journal of Ecology
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• 제17권3호
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• pp.391-413
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• 1994

The northernmost type of the monogolian oak forests in the Russian Far East was studied in terma of syntaxonomy and synchorology. Hand-sorting method, computer program TWIN-SPAN, CANOCO and SYN-TAX III were engaged for the classification and data analysis. Correlation between plant communitie and environmental factors was analyzed by DCA (Detrended Correspondence Analysis) using NeCD (Net Contribution Degree) of species. Three plant communities were recognized: the Abieti holophyllae-Quercetum mongolicae, the Lespedezo-quercetum mongolicas and the Rosa ussuriensis-Quercus mongolica communit. They were included into the alliance Jeffersonio-Quercion monogolicae which is representative to the cool-Temperate forests mixed by conierous and broadleaved trees in southern Sikhote Alin. Human impact was signified as the most important factor to interpret the disjunction of plant communities of which DCA ordination yielded sharp contrasting objects (i.e. stands and species). In the amhi-Tonghae region, alaogous vegetation types such as the Jeffersonio-Quercion monogolicae of Russian Far East, the Quercion grosseserratae of Japanese Hokkaido and the Pino koraiensis-Quercion monogolicae of Koream peninusula were reviewed in terms of similarity of species composition and stratum structure. It is signified that the Jeffersonio-Quercion monogolicae was one of the continental types more similar to Korean alliance that to Japanese one.

• Transactions on Electrical and Electronic Materials
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• 제15권3호
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• pp.113-116
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• 2014

Power transformer insulation oil is critical to the useful life of the transformer. Although mineral base insulation oil is the most common type of transformer insulation oil in use, environmental and safety concerns has encouraged the development of biodegradable alternatives. Today, $Envirotemp^{(R)}\;FR3^{TM}$ is in commercial use and this study is aimed at ascertaining the possibility of applying the oil in Malaysia power transformers. A sample of $Envirotemp^{(R)}\;FR3^{TM}$ was tested to measure and compare the technical (including electrical, chemical and physical) properties of the oil according to Malaysian standards. The study found that the oil sample had better qualities, such as higher dielectric strength, lower dissipation factor, higher flash and fire points, higher moisture absorption capability, and less dissolved gases composition amongst others. However, it was also ascertained that further development in this area could be hindered due to Malaysia's lack of standards for biodegradable oil.

• 한국실내디자인학회:학술대회논문집
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• 한국실내디자인학회 2004년도 추계학술발표대회 논문집
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• pp.15-18
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• 2004

The study focused on residents' preference for planning components according to preferred size of high-rise condominiums. After being examined not only a brief chronological review of spatial composition and planning components in high-rise condominiums but also residents' attitudes toward and preference for current planning components, this research developed a wide range of planning components included in the questionnaire. The main survey was designed to find out the needs of residents for planning components in relation to high-rise condominiums. Descriptive and factor analysis were utilized to find out the residents' different preference for planning components. The findings of this study showed that residents were very aware of healthy housing, environmental friendly housing and digitally equipped housing, and their preference was different according to preferred size of condominium housing. In other words, residents preferring condominium housing with 99m$^2$ or smaller considered features of safety and healthy housing as important, those with between 102.3m$^2$ to 115.5m$^2$ recognized experiential space, and those with 118.8m$^2$ or larger regarded features of housing management and storage as important. It is suggested that the needs and wants of residents for housing have been various to be customized.

• Journal of the korean society of oceanography
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• 제32권3호
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• pp.112-119
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• 1997

Coastal sediments collected near the Youngkwang Nuclear Power Plant were analysed for major(Al$_2$O$^_3$, Fe$^_2$O$^_3$, MgO, CaO, Na$^_2$O, K$^_2$O, TiO$^_2$, MnO), trace (Ba, Sr, V, Co, Cr, Cu, Ni, Zn, Pb) metal, and P$^_2$O$^_5$ contents. The composition of bulk metals from most stations fits within the range as those in the average crustal and sedimentary rocks, suggesting that the anthropogenic perturbation of these components is insignificant. The abundance and distribution of total contents for the majority of metals in the surface sediment could be explained by the grain size and were associated with mud (<63 ${\mu}$m) contents. However, distributions of Ca, K, Sr and Ba did not have any significant association with the sediment grain size. This may be due to the geochemical coherence among these metals in certain minerals abundant in coarse grained fractions. The distribution of Pb appears to be partly affected by the contribution from aerosol fallout. Using the R'-mode factor analysis, we show that the variance of the metal contents could be explained by four factors which account for 93.7% of the total variance. It appears that texturally controlled and/or sorting factors influenced by fine fraction are the most dominant factors which determine the relative abundance and distribution of metals in the study area.

• 한국환경과학회지
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• 제23권3호
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• pp.447-457
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• 2014

The number concentrations, the mass concentrations and the elemental concentrations of $PM_{10}$ have measured at Gosan site in Jeju, Korea, from March 2010 to December 2010. And the correlation and the factor analysis for the number, the mass and the elemental concentrations of $PM_{10}$ are performed to identify their relationships and sources. The average $PM_{10}$ number concentration is observed $246\;particles/cm^3$($35.7{\sim}1,017\;particles/cm^3$) and the average $PM_{10}$ mass concentration is shown $50.1{\mu}g/m^3$($16.7{\sim}441.4{\mu}g/m^3$) during this experimental period. The number concentrations are significantly decreased with increasing particle size, hence the concentrations for the smaller particles less than $2.5{\mu}m$($PM_{2.5}$) are contributed 99.6% to the total $PM_{10}$ number concentrations. The highest concentration of the 20 elements in $PM_{10}$ determined in this study is shown by S with a mean value of $1,497ng/m^3$ and the lowest concentration of them is found by Cd with a mean value of $0.57ng/m^3$. The elements in $PM_{10}$ are evidently classified into two group based on their concentrations: In group 1, including S>Na>Al>Fe>Ca>Mg>K, the elemental mean concentrations are higher than several hundred $ng/m^3$, on the other hand, the concentrations are lower than several ten $ng/m^3$ in group 2, including Zn>Mn>Ni>Ti>Cr>Co>Cu>Mo>Sr>Ba>V>Cd. The size-separated number concentrations are shown positively correlated with the mass concentrations in overall size ranges, although their correlation coefficients, which are monotonously increased or decreased with size range, are not high. The concentrations of the elements in group 1 are shown highly correlated with the mass concentrations, but the concentrations in group 2 are shown hardly correlated with the mass concentrations. The elements originated from natural sources have been predominantly related to the mass concentrations while the elements from anthropogenic sources have mainly affected on the number concentrations of $PM_{10}$.

• 한국세라믹학회지
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• 제52권3호
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• pp.215-220
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• 2015

Phase evolution, microstructure, and microwave dielectric properties of $Li_2O$ and $Al_2O_3$ doped $Zn_{1.9}Si_{1.05}O_4$, i.e., $Zn_{1.9-2x}Li_xAl_x-Si_{1.05}O_4$, ceramics (x = 0.02 ~ 0.10) were investigated. The ceramics were densified by $SiO_2$-rich liquid phase composed of the Li-Al-Si-O system, indicating that doped Li and Al contributed to the formation of the liquid. As the secondary phase, ${\beta}$-spodumene solid solution with the composition of $LiAlSi_3O_8$ was precipitated from the liquid during the cooling process. The dense ceramics were obtained for the specimens of $$x{\geq_-}0.06$$ showing the rapid densification above $1000^{\circ}C$, implying that a certain amount of liquid is necessary to densify. The specimen of x = 0.06 sintered at $1050^{\circ}C$ exhibited good microwave dielectric properties; the dielectric constant and the quality factor ($Q{\times}f_0$) were 6.4 and 11,213 GHz, respectively.

• 한국환경생태학회지
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• 제34권4호
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• pp.304-317
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• 2020

금남호남·호남정맥 마루금 일대 식생구조를 알기 위해 입지환경과 인위적 영향을 고려해 금남호남정맥 2곳, 호남정맥 4곳을 중점조사지로 골라 식생조사를 실시했다. TWINSPAN을 써서 두 정맥은 각각 7개씩의 식물군락으로 유형화됐다. TWINSPAN기법의 식별종은 식물군락의 환경요인을 간접적으로 대변하는데 두 정맥의 군락 유형은 해발고, 토양수분, 교란 등의 환경요인에 의해 분할됐다. 이 결과는 DCA 1축의 환경요인과 조화를 이루었다. 두 정맥은 모두 저지대에선 리기다소나무, 곰솔 등의 조림수종과 자생종이 서로 경쟁 관계에 있었다. 이처럼 정맥의 저지대는 조림, 개발사업 등으로 인위적 식생교란이 심한 편이었다. 상대적으로 고지대의 능선부·상부사면·정상부는 신갈나무·굴참나무·소나무가 우점하는 식생유형이 양호하게 보전됐다. 차이점으론 금남호남정맥은 호남정맥보다 해발고와 위도가 높아 신갈나무우점군락이 가장 넓게 분포했다. 반면, 호남정맥은 신갈나무와 함께 소나무우점군락이었고, 남해안에 인접해 있어 곰솔우점군락이 출현했다는 점이다. TWINSPAN과 DCA 등의 정량적 식생분석에선 종조성 변화와 그 변화를 일으키는 환경요인 추출이 중요하다. 이를 위해선 우연 출현종 제거와 환경요인을 상정한 조사계획 수립, 조사데이터의 특성에 부합한 최적의 분석기법 선택 등이 필요하다.

• 한국환경복원기술학회지
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• 제11권4호
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• pp.75-90
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• 2008

The golf course has many problems that are a pollution of river, a extinction of habitat by destructing a forest and a simplication of species composition. Therefore, this study was carried out to examine the ecological characteristics of vascular plants in construct-reserved site of golf course. The results were as follow. The vascular plants were summarized as 342 taxa; 86 families, 231 genera, 295 species, 42 varieties and 5 forma. In the results by the location environments of vegetation, Salix caprea community and wetland species like Persicaria thunbergii were appeared in the swamp. Especially, S. caprea will be made use of promoting a landscape. In the stream, Stephanandra incisa community has a functions like an ecological axis and a corridor of wild animals. The planting technique will be applied to using Atractylodes japonica and Ainsliaea acerifolia in the lower part of Pinus densiflora and Quercus mongolica. Because Rhododendron schlippenbachii and Convallaria keiskei grew by layer in Q. variabilis community, this will be made use of natural vegetation model. The rare plants were 2 taxa; Aristolochia contorta and Iris ensata var. spontanea. To preserve their community, we will prohibit a development and remove a threatening factor. The endemic plants were 4 taxa; Salix caprea, Clematis trichotma, Spiraea prunifolia for. simpliciflora and Weigela subsessilis. The naturalized plants were 19 taxa; Rumex crispus, Bildedykia dumetora and so on. To establish the quantitative management plan, we will obtain a ecological information about a naturalized plants in accumulating by season, community and land use pattern.

• Journal of Korean Society for Atmospheric Environment
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• 제16권E2호
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• pp.69-77
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• 2000

Measurements of non-methane hydrocarbons (NMHC) were carried out in the Sangdo tunnel and on a nearby roadway in Seoul during the during the periods of heavy(low speed with ∼20km h(sup)-1) and light(high speed with ∼60kmh(sup)-1) traffic in February 2000. In the tunnel, the total NMHC levels during the heavy traffic period were higher than those during the light traffic period by a factor of 2. This was due to the increase of emissions at the low vehicle speed period and the higher dilution effect derived from faster flow of tunnel air at the high vehicle speed period. The average total NMHC concentration in the tunnel was 1.7 times as high as that on the roadway. The species with the highest concentration in the tunnel was ethylene(50.1 ppb), followed by n-butane(34.1 ppb) and propane (21.9 ppb). The concentration ranking in the tunnel was generally in good agreement with that on the roadway, suggesting that the NMHC compositions in the tunnel and on the nearby roadway were primarily determined by vehicle exhausts. However, the NMHC compositions in the Sangdo tunnel do not agree well with other foreign study results, reflecting that the characteristics of vehicle exhausts of Seoul is different from those of other cities. The most prominent difference between this study and other studies is the high mass fractions of butanes and propane. It was be attributed to the wide use of butane-fueled vehicles.

• 한국환경과학회지
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• 제24권2호
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• pp.253-260
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• 2015

Enlargement of street tree planting area is the proper and effective solution to reduce carbon dioxide. This solution bases on the ability of carbon storage and uptake by tree metabolism. However, the circumstance of road side has fatal disadvantages in tree metabolism such as growth and maturity because cutting and filling of roadsides cause unnatural soil composition. In this point, early rootage of street tree is the main factor of reducing carbon dioxide. This study aimed to find a appropriate transplantation planting method for sound and rapid rootage of street tree. For the study, Korean Mountain Ash(Sorbus alnifolia) were used for experimental groups. The groups were categorized by three groups such as trees produced on container with mulching treatment, trees produced in outdoor with mulching treatment, trees produced on container with weeding treatment. Each group consisted 10 trees with same size and transplanted in experimental site. Five months after transplanting, each group was estimated the biomass and carbon storage through a direct harvesting method. According to results of the study, the carbon storage of trees produced on container with mulching treatment is 42% more than trees produced in outdoor with mulching treatment. And the carbon storage of trees produced on container with mulching treatment is 19.5% more than trees produced on container with weeding treatment. These results may imply that transplantation of container produced tree with mulching treatment is the most rapid rootage among other groups. The weeding treatment is more effective than mulching treatment for rapid rootage of street trees.