• 대한전기학회논문지:전력기술부문A
• /
• 제51권11호
• /
• pp.559-567
• /
• 2002

This paper presents the general recommendations for the overload criterions of mineral-oil-immersed distribution transformers rated 100kVA and less. For this purpose, we analyze the characteristics of top-oil temperature rising for mineral-oil-immersed power distribution transformer rated 100kVA and less, manufactured in Korea, In order to analyze the characteristics of top-oil temperature rising due to the distribution transformer loading, we performed experiments at KERI (Korea Electrical Research Institute) from December 2000 to May 2001. The restraint of ambient temperatures for the experiment results is solved using the results of foreign standards. Finally, we present the overload criterions of distribution transformer for summer and winter season, respectively.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
• /
• pp.66-67
• /
• 2008

Most mineral resources are located in subsurface but mineral exploration starts with a step of investigation in wide-area to find evidence of buried ores. Conventional technique for exploration on wide-area as a preliminary survey is an observation using naked eyes by geologist or chemical analysis using lots of samples obtained from target area. Hyperspectral remote sensing can overcome those subjective and time consuming survey and can produce mineral resources distribution map. Precise resource map requires information of mineral distribution in a subpixellevel because mineral is distributed as rock components or narrow veins. But most hyperspectral data is composed of pixels of several meters or more than ten meters scale. We reviewed subpixel unmixing algorithms which have been used for geological field and tested detection ability with Hyperion imagery, geological map and seven spectral curves of mineral and rock specimens which were obtained from study areas.

• Ocean and Polar Research
• /
• 제36권4호
• /
• pp.319-326
• /
• 2014

Mineral dust in the polar snow plays an important role both in the climate system of the Earth and in global biogeochemical cycles. Analysis of the concentration and the particle size distribution of mineral dust has been carried out in the snow from the Antarctic surface snow and the Greenland snowpit. Among the various particle size determination techniques, a Multisizer 3 Coulter Counter in a class 100 clean bench counted all particles between 1.1 and $30.0{\mu}m$ with a $50{\mu}m$ aperture tube. The aperture tube size, the concentration of electrolytes and the accuracy of the particle size distribution were determined in this study. The number concentrations from the Antarctic surface snow were 81,843 particles $mL^{-1}$, but those from the Greenland snowpit were 10,666 particles $mL^{-1}$. In the volume distribution, the distributions of mineral dust in both the Antarctic surface snow and the Greenland snowpit showed lognormal distribution in the size interval 1.1 to $6.0{\mu}m$ with the mode, 3.562 and $3.836{\mu}m$, respectively. The analysis technique using a coulter counter for mineral dust could be used for reconstructing paleoclimates from polar ice cores.

• Geomechanics and Engineering
• /
• 제18권2호
• /
• pp.205-213
• /
• 2019

A calculation model of reservoir pressure field distribution around multiple production wells in a heavy oil reservoir is established, which can overcome the unreasonable uniform-pressure value calculated by the traditional mathematical model in the multiwell mining areas. A calculating program is developed based on the deduced equations by using Visual Basic computer language. Based on the proposed mathematical model, the effects of drainage rate and formation permeability on the distribution of reservoir pressure are studied. Results show that the reservoir pressure drops most at the wellbore. The farther the distance away from the borehole, the sparser the isobaric lines distribute. Increasing drainage rate results in decreasing reservoir pressure and bottom-hole pressure, especially the latter. The permeability has a significant effect on bottom hole pressure. The study provides a reference basis for studying the dynamic pressure field distribution before thermal recovery technology in heavy oilfield and optimizing construction parameters.

• 한국제4기학회지
• /
• 제17권2호
• /
• pp.153-156
• /
• 2003

• Journal of Ginseng Research
• /
• 제4권1호
• /
• pp.55-64
• /
• 1980

The distribution pattern of mineral nutrients, among various Parts of Korea ginseng (Panax ginseng C.A. Meyer) was investigated to understand ginseng nutrition by simple correlation analysis. Five·year old ginseng plants grown under four different nutritional environments were sampled and separated into leaf, petiole, stem, rhizome, cortex and epidermis of tap foot, central part of tap root, cortex and epidermis of lateral root, central part of lateral root, fine root in the middle of truly, for chemical analysis. Between mineral nutrients in root, N and P showed highly significant positive correlation each other and with Mg and Cu while all other elements (K, Ca, Mg, Fe, Mn, Zn, Cu, B) showed highly significant positive correlation each other. In shoot, number of mineral nutrient pairs haying significant relation was much less than in root. (Negative: P with Ca or B, K with N, Fe, Mn or Cu, Positive: N with Mg, Fe, Mn or Cu, K with Zn, Ca with Mg, Zn, or B, Fe Mn Cu each other, Mn with B.) The number of pairs having significant correlation in whole plant was approximately the same as the number in root but three of them showed significant negative correlation. The distribution pattern similarity of mineral contents among various parts was also discussed in relation to physiological significance in Korea ginseng plant.

• Asian-Australasian Journal of Animal Sciences
• /
• 제9권2호
• /
• pp.139-147
• /
• 1996

Eight Philoppine forages were studied to obtain the following: 1) nutrient concentrations and digestibility, 2) distribution of the various minerals in fiber fractions through mineral analyses of neutral detergent fiber(NDF) and acid detergent fiber(ADF) residues, and 3) correlation coefficients among the factors affecting forage quality and mineral concentrations. These Philippine forages were paragrass [Brachiaria mutica (Forsk.) Stapf], stargrass (Cynodon plectostachyum Pilger), napiergrass (Pennisetum purpureum Schumach.) calopo (Calopogonium muconoides Desv.), centrocema (Centrocema pubescens Benth.), gliricidia [Gliricidia sepium (Jacq.) Walp.] leucaena [Leucaena leucocephala (Lam.) de Wit.] and sesbania [Sesbania grandiflora (L.) Poir]. Species differences(p<0.01) were observed on various nutrient fractions including mineral composition and digestibility. The cell wall(NDF) fraction, prepared by boiling in neutral detergent solution, contained the following proportions of the total mineral originally present (%): calcium (Ca), 0.7; phosphorus(P), 14.3; magnesium(Mg), 1.9; potassium(K), 3.7; copper(Cu), 16.4; zinc(Zn), 2.9; molybdenum(Mo), 9.3; cobalt(Co), 16.2; manganese(Mn), 5.6, and iron(Fe), 81.3. The ligno-cellulose(ADF) fraction, prepared by boiling in acid detergent solution, contained the following proportions of the total mineral originally present(%): Ca, 0.2; P, 4.4; Mg, 0.7; K, 2.8; Cu, 32.3; Zn, 1.1; Mo, 8.9; Co, 4.7; Mn, 5.4; and Fe, 36.8. Correlation coefficients among the factors affection forage quality and mineral concentrations were also observed. Evidently, 75 and 45% of the minerals in grasses and legumes was positively correlated to CP and IVDMD, respectively. Moreover, 55, 80 and 75% of the forage minerals was negatively correlated to NDF, ADF and ADL fraction, respetively, implying that most of the minerals reside in the non-structural cell components.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제25권2_spc호
• /
• pp.86-100
• /
• 2020

Analyzing and monitoring environmental contaminants based on geophysical exploration techniques have become important and it is now widely applied to delineate spatial distribution geophysical characteristics in wide area. Among the techniques, induced polarization (IP) method, which measures polarization effects on electrical potential distribution, has drawn much attention as an effective tool for environmental monitoring since IP is sensitive to changes in biochemical reactions. However, various reactions stemming from the presence of multiple contaminants have greatly enhanced heterogeneity of polluted sites to result in highly variable electrical characteristics of the site. Those contaminants influence chemical and physical state of soil and groundwater to alter electrical double layer, which in turn influences polarization of the media. Since biochemical reactions between microbes and contaminants result in various IP effects, IP laboratory experiments were conducted to investigate IP responses of the contaminated soil samples under various conditions. Field IP surveys can delineate the spatial distribution of contamination, while providing additional information about electrical properties of a target medium, together with DC resistivity. Reviewing IP effects of contaminants as well as IP surveys can serve as a good starting point for the application of IP survey in site assessment for environmental remediation.

• 한국광물학회지
• /
• 제21권3호
• /
• pp.289-295
• /
• 2008

해양퇴적물 전체 시료 내에 존재하는 각 점토광물의 함량비(전대광물조성)와 점토광물들만을 100%로 환산했을 때 각 점토광물의 함량비(상대광물조성)를 구한 후, 지도에 도시하여 그 분포 양상을 비교하여 보았다. 시료는 한국해양연구원의 2001년 황해 2차 탐사에서 채취된 86개 표층 퇴적물 시료를 사용하였으며, 정량X선회절분석법을 이용하여 광물조성을 구하였다. 황해 표층 퇴적물은 주구성광물(석영 평균 44.7%, 사장석 15.9%, 알카리장석 13.9%. 각섬석 2.8%), 점토광물(일라이트 15.3%, 녹니석 2.6%, 카올리나이트 1%), 탄산염광물(방해석 1.7%, 아라고나이트 0.6%) 등으로 구성되어 있다. 점토광물들은 대체로 황해의 가장자리에 적은 분포를 보이고 산동반도 남동쪽에서 제주도 남서쪽을 연결하는 해역에서 높았으며, 세립질 퇴적물의 분포와 거의 일치하는 경향을 나타낸다. 점토광물들의 합을 100으로 가정하고 구한 점토광물의 평균 상대광물조성은 일라이트, 녹니석, 카올리나이트가 각각 80.3%, 14.9%, 4.8%이다. 점토광물들의 상대광물조성을 이용하여 나타낸 분포 양상은 절대광물 조성을 이용하여 구한 그것과 많은 차이를 보이며, 점토광물을 많이 포함하고 있는 세립질 퇴적물의 분포경향과도 정의 상관관계를 보이지 않는다. 그러므로 점토광물들만을 대상으로 상대광물조성을 구하여 퇴적물 근원지 해석 등에 이용할 때에는 상당히 신중을 기한 필요가 있는 것으로 판단된다.

• Communications for Statistical Applications and Methods
• /
• 제14권3호
• /
• pp.517-530
• /
• 2007

We studied a modelling process for unimodal and multimodal circular data by using von Mises and its mixture distribution. In particular we suggested EM algorithm to find ML estimates of the mixture model. Simulation results showed the suggested methods are very accurate. Applications to two kinds of real data sets are also included.