• Journal of ILASS-Korea
• /
• v.2 no.1
• /
• pp.18-28
• /
• 1997

The present study is mainly aiming at numerically analyzing the combustion and emission characteristics of the diesel spray in a high-pressure environment. Computations are peformed for the peak chamber pressure with range from 4.08 MPa to 162 MPa. Numerical results indicate that the pressure increase in combustion chamber significantly influences the mechanism for droplet dynamics and mixing characteristics, spray penetration autoignition, flame lift-on height and the propagation or fuel vapor and flame. By increasing the ratio or the ambient density to injected liquid density, the fuel-air mixing rates and the burning rates increase and the $NO_x/soot$ emission level decreases.

• Journal of the Korean Institute of Gas
• /
• v.12 no.4
• /
• pp.52-57
• /
• 2008

This paper studies on the wear corrosion behavior of induction hardening high strength cast iron in the acidic environments. In a variety of pH solutions, wear corrosion behavior of GC 300 with a variety of contact pressures was investigated, and corrosion wear behavior after immersion test was considered. Also, electrochemical polarization test for GC 300 was carried out in various pH solutions. The main results are as following: In the strong acidic environment, wear corrosion rate of GC 300 appears highly and in the neutral environment is stable. Also, graphitic corrosion in the strong acidic environment occurs. The corrosion current density of GC 300 becomes high in a order of pH 1 > pH 2 > pH 4 > pH 6.5.

• Architectural research
• /
• v.16 no.3
• /
• pp.81-92
• /
• 2014

This study discusses the features of the lighting and ventilation regulations for residential buildings in Hong Kong. Given the compact built environment and public concerns about the environmental quality of housing, various lighting and ventilation regulations have been enacted in Hong Kong. The application of building regulations on the micro scale and incentive systems on the macro scale are present, and the governments' calls for more active participation of the private sector and use of the building environmental assessment tools were also noted. Unlike South Korea, however, Hong Kong was found to adopt more performance-based standards, consider the external factors of the lighting and ventilation conditions together with the indoor elements, and provide specific design guidelines. Notwithstanding the different climatic conditions and socio-political contexts of Hong Kong and South Korea, these findings provide some policy implications for the South Korean government in its efforts to achieve a healthy environment for high-rise, high-density housing. It is suggested that the South Korean government adopt more on-site measurement methods to reflect the environmental conditions accurately and broaden the scope and scale of the implementation of the lighting and ventilation regulations with more specific, practical planning and design guidelines.

• Land and Housing Review
• /
• v.5 no.3
• /
• pp.131-136
• /
• 2014

The Hong Kong Housing Authority (HKHA) develops and implements a public housing programme to meet the housing needs of people who cannot afford private rental housing. The HKHA has an existing stock of about 740,000 public rental flats (PRH). According to the 2014 Policy Address, the Government aims to provide an average of about 20,000 PRH units and about 8,000 Home Ownership Scheme (HOS) units per year. We care for the environment. In developing new housing estates, we conduct thorough environmental studies such as microclimate studies and air ventilation assessment, and use passive design to harness the natural characteristics of our sites. We employ environment-friendly design and construction methods, using modular flat design, pre-cast and pre-fabricated construction techniques as well as recycled, green construction materials. We conduct Carbon Emission Estimation for all our projects, conserve the use of natural resources and reduce wastes throughout the life cycle of buildings. We care for people. We adopt the principles of Universal Design and Barrier Free Access for the convenience and welfare of people of all ages and abilities. We carry out Community Engagement to collect stakeholders' views and aspirations, and incorporate them in the design of our projects. We also carry out surveys of residents' views after the occupation of new estates to gauge our success and identify areas for improvement.

• Journal of Magnetics
• /
• v.20 no.1
• /
• pp.86-90
• /
• 2015

Electromagnetic actuators are versatile and able to meet demanding requirements, such as operation in very low or very high temperatures. When the actuator is used in a high-temperature environment up to $500^{\circ}C$, we need to know how the force-producing capability of the actuator is affected by the operating temperature. Specifically, it is necessary to know the temperature-dependence of magnetic properties that determine the mechanical forces. In this paper, we measure the changes in magnetic properties of SUS410 material in high-temperature environment. We also devise a novel signal processing technique to remove the integration drift. At the field strength of 18,000 A/m, we found that the flux density at $500^{\circ}C$ is decreased by 26%, compared to the result at room temperature. Therefore, the actuator must be sized appropriately, if it is to operate in high-temperature settings.

• Journal of Environmental Science International
• /
• v.18 no.8
• /
• pp.885-897
• /
• 2009

In order to make sure the impact of spatial resolution of wind energy map on the estimation of wind power density in the Korean Peninsula, the comparison studies on the characteristics of wind energy map with three different spatial resolutions were carried out. Numerical model used in the establishment of wind map is MM5 (5th generation Mesoscale Model) with RBAPS (Regional Data Assimilation and Prediction System) as initial and boundary data. Analyzed Period are four months (March, August, October, and December), which are representative of four seasons. Since high spatial resolution of wind map make the undulation of topography be clear, wind pattern in high resolution wind map is correspond well with topography pattern and maximum value of wind speed is also increase. Indication of island and mountains in wind energy map depends on the its spatial resolution, so wind patterns in Heuksan island and Jiri mountains are clearly different in high and low resolutions. And area averaged power density can be changed by estimation method of wind speed for unit area in the numerical model and by treatment of air density. Therefore the studiable resolution for the topography should be evaluated and set before the estimation of wind resources in the Korean Peninsula.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.44 no.3
• /
• pp.214-220
• /
• 1999

Rice production in Korea has markedly increased during the last two decades due to newly developed high yielding varieties and improved production technology. This experiment was conducted to determine the potential of tropical japonica germplasm in enhancing the yield of temperate japonica. The yield performance of two tropical japonicas (IR 65597-29-3-2 and IR66154-52-1-2) and one temperate japonica (Dongjinbyeo) was compared at different plant densities and nitrogen levels under Korean environmental conditions. Although tropical japonicas showed low tillering habit and large panicles, they had similar leaf area index and dry weight at heading stage to Dongjinbyeo of the high tillering type indicating that there was not much difference between tropical and temperate japonica in terms of biomass production. The highest milled rice yield of 6.15 t/ha was obtained from Dongjinbyeo at a high nitrogen level with less planting density (220 kg N/ha and 30 $\times$ 15 cm). However, those of the two tropical japonicas were 5.36 t/ha at the condition of 165 kg N/ha and 30 x 10 cm planting density and 5.06 t/ha at the condition of 165kgN/ha and 15 x 15 cm planting density, respectively. Ripened grain of tropical japonicas ranged from 65 to 87%, while that Dongjinbyeo ranged from 82 to 97% under Korean conditions.

• The Bulletin of The Korean Astronomical Society
• /
• v.35 no.2
• /
• pp.41.1-41.1
• /
• 2010

It has been suggested that merging plays an important role in the formation and the evolution of early-type galaxies. Optical-NIR color gradients of early-type galaxies in high density environments are found to be less steep than those in low density environment, hinting frequent merger activities in early-type galaxies in high density environment. In order to confirm if the flat color gradient is the result of dry merger, we decided to look deeply to find merging features and get their relation with color gradient. We selected samples which show extreme values of optical-NIR color gradients based on the data of previous study, and observed them at Maidanak observatory 1.5m telescope with long exposure. After masking out overlaid sources, our analysis reveals that these galaxies do not have extreme color gradient values. High degree sky flat technique was used during observation to aid discovery of faint, extended features. However, flatness of detector (SNUCAM) was good enough, so we could not see any marked improvement in image quality compared to those using normal sky flats. Additionally we noticed a feature that looks like merging tidal tail in the CFHT archival image, but this does not show up on the image we obtained. This demonstrates that flatness and correct sky estimation is very important when we look for faint merging features. In future we plan to enlarge the number of the sample.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.23 no.2
• /
• pp.49-67
• /
• 2020

This study was conducted to compare and analyze forest vegetation distributed in Geumosanseong-inside in Geumosan Provincial Park from 2017.10 to 2019.6. The vegetation structure was classified by the phytosociological method and TWINSPAN and the correlation between the community structure and the environmental factors was analyzed using DCCA ordination analydsis. The vegetation structures are Quercus mongolica, Fraxinus mandshurica, Q. acutissima, Larix leptolepis, Prunus padus and Morus alba community by the phytosociological method and 16 communities under TWINSPAN. The importance value of Q. mongolica(64.5) was the highest, and followed by F. mandshurica, L. leptolepis, Acer pseudosieboldianum, M. alba, P. padus, Q. acutissima, Sorbus alnifolia, P. serrulata var. pubescens, F. sieboldiana, Rhododendron schlippenbachii and Castanea crenata which is consistent with species having the dominance status by analysis of the vegetation structure. As the results of DBH analysis for taxon with high importance values, Q. mongolica and M. alba represented normal distribution, and thus, the dominance status of these species is likely to continue. L. leptolepis will maintain the dominance status due to high density of large individuals as compared with species above medium size. However, it will decrease because of high mortality after increase in age class. F. mandshurica and P. padus continue to show dominance status due to high density of young individuals as compared with species above medium size. Q. acutissima have high density of individuals above intermediate size and low density of young individuals, and thus, will maintain the dominance status. A. pseudosieboldianum, F. sieboldiana and R.schlippenbachii which are arborescent will present continuously high dominance status because of high density of young individuals. Soil analysis shows that whereas pH, Ca²⁺ and Mg²⁺ in the research area were lower than the average values of overall forest soil and O.M, T-N, C.E.C and P₂O₅ were higher. We expected that these results were due to agricultures until 50 years ago in Geumosanseong-inside. As a result of DCCA ordination analysis using eleven environmental factors and communities classified by the phytosociological method analysis showed that Q. mongolica was distributed in the environment with higher elevation and O.M and steep slope, and lower P₂O₅, Mg²⁺ and Ca²⁺. In contrast to F. mandshurica, Q. acutissima was distributed in higher K⁺ and lower pH. L. leptolepsis was distributed in various environment.

• Journal of the Korean housing association
• /
• v.22 no.3
• /
• pp.101-111
• /
• 2011

This study was conducted to investigate the indiscriminate development occuring as a result of high-density land use per lot in residential areas of Seoul, which mainly consist of detached houses. The primary goals of this study were: (1) to suggest a block unit development method as an alternative architectural method of the current uniform development, in which high-rise and high-density apartments are usually built; and (2) to check the feasibility of the suggested method. Based on the analyses of the existing block composition types of residential areas, the prerequisite planning indices for applying a collective housing model were investigated. Subsequent to applying a collective housing type within each unit block, the collective housing model was analyzed. The results of the analyses showed that indiscriminate development was rampant in detached urban houses areas, and more than 70% of the buildings constructed before the 1980s needed re-development. The feasibility of the models was investigated depending on the models of low-rise and high-density collective housing, which utilize various block arrangements such as the court type, linear type, villa type, and composite type. The results of this study showed that the newly applied low-rise and highdensity multiple dwelling housing model in urban individual residential area significantly contributed to creating a good living environment in terms of both physical and psychological aspects.