• Journal of Power Electronics
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• 제5권4호
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• pp.257-263
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• 2005

This paper describes the development and testing results of a high density High Voltage Power Supply (HVPS) that drives microwave Traveling Wave Tubes (TWTs) of phased array transmitters for airborne EW systems. The HVPS is designed to consist of a number of modules connected in series. Among them, especially, the high-density pulse transformer module including the resonant circuit is newly designed to make the HVPS much more reliable. In addition, this paper describes the development of high voltage solid-state modulation using fast switching devices (FETs) and also represents the test results of a modulator module.

• 드라이브 ㆍ 컨트롤
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• 제21권2호
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• pp.30-35
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• 2024

Domestic rice is more expensive than imported products, so it is necessary to reduce production costs to secure competitiveness. Low-density planting developed in Japan is a cultivation technology that reduces labor and production costs without yield loss. The area of low-density cultivation is continuously increasing. However, research on how rice transplanters adapt to low-density planting has not been conducted. Therefore, this study was carried out to determine the optimal working conditions of a rice transplanter for low-density planting. Three types of rice transplanters were used and treated based on 3 conveying distance levels. The number of picked seedlings, pick missing rate, the number of planted seedlings, and the mis-planted rate were investigated to evaluate planting accuracy according to the transfer distance to the seedling tray. The results showed that the number of planted seedlings was 4.31~4.95 EA with an L1 seedling tray transfer distance (horizontal 9 mm, vertical 8 mm), but the mis-planted rate was higher than in other conditions. At L2 (horizontal 9 mm, vertical 10 mm) and L3 (horizontal 11 mm, vertical 8 mm) transfer distance conditions, the number of planted seedlings were 4.89-5.68 EA and 4.69-5.66 EA, respectively, with a low mis-planted rate of less than 3%. The results showed that if the transfer distance is adjusted properly, a rice transplanter can be used for low-density planting with high planting accuracy.

• 한국주거학회:학술대회논문집
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• 한국주거학회 2009년도 추계학술발표대회 논문집
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• pp.132-137
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• 2009

The purpose of this study was to suggest urban regeneration methods for deteriorated downtown residential area, considering the development condition of urban blocks. Through the research that are based on literature, field survey, urban planning map and local experts consulting, it found out suitable sites for development such as a deteriorated residential zone or a unused site and it was deduced eight development types from analyzing the characters of developable sites. And then it is suggested various housing forms which were applied to eight development types of developable sites. The consequences of this research are summarized as follows. There are various housing forms by eight development types; block housing, low rise-high density court housing, medium low rise-high density housing, urban housing for low-income groups belong to T1-development of urban strategic position; block housing, housing on hilly site, semi-detached house, lodging house, urban housing for low-income groups, elderly housing belong to T2-development for living benefit; block housing, low rise-high density court housing, housing on hilly site, low rise housing, lodging housing, urban housing for low-income groups, elderly housing belong to T3-development of a small-scale rental housing; block housing, low rise-high density court housing, medium low rise-high density housing, terrace-house, housing on hilly site, low rise housing, block-typed detached house, semi-detached house, cluster-typed low rise housing, town house, urban housing for low-income groups belong to T4-residential environment renewal development; terrace-house, housing on hilly site, low rise housing, block housing, semi-detached house belong to T5-development of a small-scale housing; terrace-house, housing on hilly site, low rise housing, cluster-typed low rise housing belong to T6-development to adapt natural environment; block housing, low rise-high density court housing, low rise housing, block-typed detached house, town house belong to T7-development for community; block housing, low rise-high density court housing block housing, medium low rise-high density housing, terrace-house, housing on hilly site, low rise housing, elderly housing belong to T8-development of environment-friendly.

• 환경영향평가
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• 제12권3호
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• pp.151-160
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• 2003

Analysis of carrying capacity and site suitability by the systematic application of environmental information an provide a basis for implementing environmentally sensitive and sustainable resource development policies. Based on the availability of public services and environmental and site-specific constraints, a Rural Residential Density Matrix was applied in Santa Cruz County, California, USA to assess the development potential of rural land parcels since 1980. In one case, the Matrix was applied to calculate the allowable development density on a site in Lompico planned for use as a Buddhist retreat center. These calculations revealed higher environmental sensitivity and lower carrying capacity than projected in the proposed plan. Under the constraints of the county's minimum acreage policies and insufficient developable land, the developer cancelled the proposed plan. This example suggests that application of the Matrix at the concept development stage would increase the effectiveness of the prior environmental review and environmental impact assessment (EIA) system in Korea.

• 한국시스템다이내믹스학회:학술대회논문집
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• 한국시스템다이내믹스학회 2003년도 하계학술대회발표논문집
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• pp.1-24
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• 2003

The purpose of this paper was developing a development density control model for urban growth management, using system dynamics modeling. The density control model was developed to see how urban growth, transition, and decay occur depending on the interaction among population, houses, industry structure, land and urban infrastructure such as road, water supply, and sewage treatment facilities. Suggesting adequate level of development density control using the model was another purpose of this paper. The model was applied to An'yang city to estimate the maximum number of population, industry structures, houses, and cars that can be adequately sustained with the current An'yang city's infrastructur capacity. The computer simulation results shows that the city is overpopulated by some 90,000 people. To reduce the population to the adequate level that the current urban infrastructure can sustain, the current city regulation on floor area ratio are needed to be strengthened at least 20 to 35%.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.799-800
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• 2006

Wrought Si-steels are generally used for electromagnetic valves, which are needed good response. To date, Hitachi Powdered Metals Co., Ltd. have produced Fe-Si base sintered magnetic material, EU-52, which shows a magnetic flux density of more than 1.25T at 2000A/m and a maximum permeability of more than 3500. However these magnetic properties are lower than that of wrought Si-steels. Because EU-52 has a low density of $7.2Mg/m^3$. For improving the magnetic properties, it is necessary to increase the density of sintered cores. To increase density, a new mixing method of coating fine Si powders on atomized iron powders was developed, for avoiding the Kirkendall effect. As the result, developed P/M Fe-Si magnetic cores shows higher density of $7.38Mg/m^3$, higher magnetic flux density of 1.48T at 2000A/m and higher maximum permeability of 6800.

• Plant Resources
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• 제8권3호
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• pp.258-262
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• 2005

In autumn, to determine the optimal planting date and plant density of rapeseed in southern areas of Korea, Yudal variety for autumn sowing, the highest yielding variety was grown under three different planting dates and five different plant densities. Yield components such as plant height, ear length, number of seedling stand per $m^2$, number of branches and pod length were highest at the plots with Sep. 30 of planting date and 30/20 cm drilling of plant density. Yield of seed, oil and 1,000 grains weight were highest at the Sep.30 of planting date and 30/20 cm drilling of plant density. Judging from the results reported above, at optimum planting date and plant density of rapeseed seemed to be Sep.30 of planting date and 30/20cm plant density in autumn sowing.

• Journal of Forest and Environmental Science
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• 제30권3호
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• pp.259-266
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• 2014

Stand Density Diagrams (SDD) are average stand-level models which graphically illustrate the relationship between yield, density and mortality throughout the various stages of forest development. These are useful tools for designing, displaying and evaluating alternative density regimes in even-aged forest ecosystems to achieve a desired future condition. This contribution presents an example of a SDD that has been constructed for teak forests of Karnataka in southern India. The relationship between stand density, dominant height, quadratic mean diameter, relative spacing and stand volume is represented in one graph. The relative spacing index was used to characterize the population density. Two equations were fitted simultaneously to the data collected from 27 sample plots measured annually for three years: one relates quadratic mean diameter with stand density and dominant height while the other relates total stand volume with quadratic mean diameter, stand density and dominant height.

• 농업과학연구
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• 제50권4호
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• pp.841-860
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• 2023

The present study was conducted to evaluate the effects of dietary mangosteen peel extract (MPE) on growth performance, serum biochemistry, jejunum morphology, and cytokine levels in growing pigs raised at a high stocking density. A total of 120 male growing pigs (43.68 ± 0.48 kg) were randomly arranged in a 2 × 2 factorial design with stocking density (high; HD, 0.55 m²/pig and normal; ND, 0.82 m²/pig) and dietary MPE (0 or 5 g/kg) as factors. Each treatment had six replicates with four or six pigs per treatment. Feed and water were provided ad libitum for 6 weeks. The HD group exhibited lower final body weight, average daily gain, and average daily feed than the ND group (p < 0.05). None of the factors affected villus height to crypt depth ratio. Dietary MPE, but not stocking density, increased IL-10 levels in the serum com-pared to the non-supplemented control diet (p < 0.05). In the microbiome analysis, alpha diversity analysis showed significant reductions in the MPE-treated group only under normal density conditions. High density stress induced gut microbiome changes and these response was differ between normal and MPE diet fed pigs. Overall, each group exhibited different major microbial composition in the gut. In conclusion, there were significant changes in the major microbial composition in response to high-density stress, and this variation was influenced by dietary treatment.

• Plant Resources
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• 제8권2호
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• pp.91-95
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• 2005

In spring, to determine the optimal planting date and plant density of rapeseed in southern areas of Korea. $Taiwan^{\#1}$ variety for spring sowing, the highest yielding variety was grown under five different planting date and plant density. Yield components such as plant height, ear length, number of seedling stand per $m^2$, number of per ear and seed set percentage were highest at the plots with Mar. 5 of planting date and 50/20cm drilling of plant density. Yield of seed, oil, gas and 1,000 grains weight and erucic acid content were highest at the Mar. 5 of planting date and 50/20cm drilling of plant density. Judging from the results reported above, at optimum planting date and plant density of rapeseed seemed too be Mar. 5 of planting date and 50/20cm plant density in spring sowing.