• Land and Housing Review
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• v.8 no.4
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• pp.223-232
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• 2017

The purpose of this study is to identify the supply status and planning trend of North Korean housing through analysis on the North Korean architecture specialized media data. The flat composition is changing and the living room is becoming the center of the houses. Also, in the urban areas, the standard apartment type is four apartments in a row and the plan form is getting diversified into circle type, Y type, and irregular type. On the other hand, in the rural areas, two houses in a row and single house are typical and the change in planning scale and space structure are not substantial. Since the 2000s, design changes have been made to emphasize the third dimensional structure of buildings such as the elliptical houses and L-shaped houses. Furthermore, 8~10 households are located on one floor which leads to the tendency of the building enlargement. In terms of house size, a square concept was introduced to replace the initial 2~3 room concept and the basic module of the room planning the 3 room house based on $3m{\times}3m$. However, there seems to be no standard house size, and the house size may differ depending on the social classandregion. In the early 1980s, when there was focus on the apartment complex construction, the high-rise apartment buildings of 30~40 floors was planned. However, during the Pyongyang redevelopment project, apartments of more or less than 10 floors were built and row-houses of more or less than 4 floors were built. In terms of the complex scale, a lot of small complexes of around 300 households are emerging after 2010. The construction projects are mainly limited to specific regions such as Pyongyang and Samjiyeon, and also limited to specific classes such as the workers and soldiers initially and the scientists lately. In addition, living boundary composition and ancillary facilities for sufficient green area ratio securement and the people of North Korea are maintained consistently. In recent years, the specialized floor planning such as solar house and the house for the disabled people, framework houses for redevelopment business, and multi-storied house construction technology are also emerging.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.5
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• pp.71-80
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• 2012

To improve the $NO_X$ conversion over a SCR (selective catalytic reduction) catalyst, the DOC (diesel oxidation catalyst) is usually placed upstream of the SCR catalyst to enhance the fast SCR reaction ($4NH_3+2NO+2NO_2{\rightarrow}4N_2+6H_2O$) using equimolar amounts of NO and $NO_2$. Here, a ratio of $NO_2/NO_X$ above 50% should be avoided, because the reaction with $NO_2$ only ($4NH_3+4NO+O_2{\rightarrow}4N_2+6H_2O$) is slower than the standard SCR reaction ($4NH_3+4NO+O_2{\rightarrow}4N_2+6H_2O$). In order to accurately predict the performance characteristics of SCR catalysts, it is therefore desired to develop a more simple and reliable mathematical and kinetic models on the oxidation kinetics of nitric oxide over a DOC. In the present work, the prediction accuracy and limit of three different chemical reaction kinetics models are presented to describe the chemicophysical characteristics and conversion performance of DOCs. Steady-state experiments with DOCs mounted on a light-duty four-cylinder 2.0-L turbocharged diesel engine then are performed, using an engine-dynamometer system to calibrate the kinetic parameters such as activation energies and preexponential factors of heterogeneous reactions. The reaction kinetics for NO oxidation over Pt-based catalysts is determined in conjunction with a transient one-dimensional (1D) heterogeneous plug flow reactor (PFR) model with diesel exhaust gas temperatures in the range of 115~$525^{\circ}C$ and space velocities in the range of $(0.4{\sim}6.5){\times}10^5\;h^{-1}$.

• KIEAE Journal
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• v.9 no.6
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• pp.73-80
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• 2009

The purpose of this paper is to suggest rules and regulations about a bike parking facility, With the objective of expanding bike parking facilities for the comfort of bikers. In Korea, the requirements to establish the facility comply with several regulations like laws for the encouragement of bike usages, rules and regulations for the encouragement of bike usages, regulations of Gyeonggi Regional Corporation rules and Korea National Housing Corporation(Korea Land and Housing Corporation) and requirements for the approval of green buildings. Such rules regulate the number of parking spots depending on the number of nearby houses and the size of a parking facility. Amongst the foreign regulations about the facility is 'obligatory regulations for the establishment of a bike parking facility' in Japan. In the United States, all states apply rules about the bike facility to determine the number of bike parking spots in accordance with the number of car parking spots. Comparing Korean rules regarding the bike parking facility with those of foreign governments will give a good insight into the current situation of Korean regulations. In order to investigate the current usage of bikes, 30 houses in Goyang city, 35 schools, 16 retails shops and 20 medical centers were researched. Thereafter, a correlation test between the size of buildings and the number of bike parking spots was carried out. The result of the test indicates that there is a lack of space for bike parking. It is recommended that the bike parking facility be installed with a convenient access to a building in order to increase the rate of bike usages.

• Journal of Powder Materials
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• v.26 no.1
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• pp.49-57
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• 2019

Layered $LiNi_{0.83}Co_{0.11}Mn_{0.06}O_2$ cathode materials single- and dual-doped by the rare-earth elements Ce and Nd are successfully fabricated by using a coprecipitation-assisted solid-phase method. For comparison purposes, non-doping pristine $LiNi_{0.83}Co_{0.11}Mn_{0.06}O_2$ cathode material is also prepared using the same method. The crystal structure, morphology, and electrochemical performances are characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) mapping, and electrochemical techniques. The XRD data demonstrates that all prepared samples maintain a typical ${\alpha}-NaFeO_2$-layered structure with the R-3m space group, and that the doped samples with Ce and/or Nd have lower cation mixing than that of pristine samples without doping. The results of SEM and EDS show that doped elements are uniformly distributed in all samples. The electrochemical performances of all doped samples are better than those of pristine samples without doping. In addition, the Ce/Nd dual-doped cathode material shows the best cycling performance and the least capacity loss. At a 10 C-rate, the electrodes of Ce/Nd dual-doped cathode material exhibit good capacity retention of 72.7, 58.5, and 45.2% after 100, 200, and 300 cycles, respectively, compared to those of pristine samples without doping (24.4, 11.1, and 8.0%).

• Journal of the Korean Institute of Landscape Architecture
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• v.46 no.2
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• pp.62-68
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• 2018

This study investigated the effect of light intensity on the removal of particulate matter by Dieffenbachia amoena 'Marianne' and Spathiphyllum spp.. An acrylic chamber ($600{\times}800{\times}1200mm$, $L{\times}W{\times}H$) modeled as an indoor space and a green bio-filter ($495{\times}495{\times}1000mm$, $L{\times}W{\times}H$) as an air purification device were made of acrylic. The removal of particulate matter PM10 and PM1, the photosynthetic rate, stomatal conductance, and number of stomata of Dieffenbachia amoena 'Marianne' and Spathiphyllum spp. were measured according to three different levels of light intensity (0, 30 and $60{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}PPFD$). Regarding the length of time taken for PM10 to reach $1{\mu}g$, the Dieffenbachia amoena 'Marianne' showed a significant difference according to the presence or absence of light, and there was no significant difference shown between light intensity of 30 and $60{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}PPFD$. As for the Spathiphyllum spp., there was no significant difference between 0 and $30{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}PPFD$, while a significant difference was shown at $60{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}PPFD$. After 90 minutes, the PM1, PM10, and $CO_2$ residuals of the Spathiphyllum spp. were lowest at $60{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}PPFD$. The remaining amount of PM1 and PM10 was lower with the Spathiphyllum spp. than with the Dieffenbachia amoena 'Marianne', even at $0{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}PPFD$. With both plants, the higher the light intensity, the higher the photosynthetic rate, while the stomatal conductance did not show any significant difference. Spathiphyllum spp. showed a higher photosynthetic rate and stomatal conductance and a greater number of stomata than Dieffenbachia amoena 'Marianne', and stomata were observed in both the front and back sides of the leaves. The air purification effect of Spathiphyllum spp. is considered to be better than Dieffenbachia amoena 'Marianne' at the same light intensity due to such plant characteristics. Therefore, in order to select effective indoor plants for the removal of particulate contamination in an indoor space, the characteristics of plants such as the photosynthetic rate and the number and arrangement of stomata according to indoor light intensity should be considered.

• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.4
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• pp.347-365
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• 2020

In order to resolve traffic problems in urban areas and to increase the area of green spaces, tunnels in downtown areas are being increased. Additionally, the application of large port smoke extraction ventilation systems is increasing as a countermeasure to smoke extraction ventilation for tunnels with high potential for traffic congestion. It is known that the smoke extraction performance of the large port smoke extraction system is influenced not only by the amount of the extraction flow rate, but also by various factors such as the shape of the extraction port (damper) and the extraction air velocity through a damper. Therefore, in this study, the design standards and installation status of each country were investigated. When the extraction air flow rate was the same, the smoke extraction performance according to the size of the damper was numerically simulated in terms of smoke propagation distance, compared and evaluated, and the following results were obtained. As the cross-sectional area of the smoke damper increases, the extraction flow rate is concentrated in the damper close to the extraction fan, and the smoke extraction rate of the damper in downstream decreases, thereby increasing the smoke propagation distance on the downstream side. In order to prevent such a phenomenon, it is necessary to reduce the cross-sectional area of the smoke damper and increase the velocity of passing air through the damper so that the pressure loss passing through the damper increases, thereby reducing the non-uniformity of smoke extraction flow rate in the extraction section. In this analysis, it was found that when the interval distance of the extraction damper was 50 m, the air velocity passing through damper was 4.4 m/s or more, and when the interval distance of the extraction dampers was 100 m, the air velocity passing through damper was greater than 4.84 m/s, it was found to be advantageous to ensure smoke extraction performance.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.12
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• pp.840-846
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• 2012

Global climate changes caused by $CO_2$ emissions are currently debated around the world; green sources of energy are being sought as alternatives to replace fossil fuels. The sustainable use of biogas for energy production does not contribute to $CO_2$ emission and has therefore a high potential to reduce them. Catalytic steam reforming of a model biogas ($CH_4:CO_2$ = 60%:40%) is investigated to produce $H_2$-rich synthesis gas. The biogas utilized 3D-IR matrix burner in which the surface combustion is applied. The ruthenium catalyst was used inside a reformer. Parametric screening studies were achieved as Steam/Carbon ratio, biogas component ratio, Space velocity and Reformer temperature. When the condition of Steam/Carbon ratio, $CH_4/CO_2$ ratio, Space velocity and Refomer temperature were 3.25, 60% : 40%, $14.7L/g{\cdot}hr$ and $550^{\circ}C$ respectively, the hydrogen concentration and methane conversion rate were showed maximum values. Under the condition mentioned above, $H_2$ yield, $H_2$/CO ratio, CO selectivity and energy efficiency were 0.65, 2.14, 0.59, 51.29%.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.6
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• pp.97-107
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• 2013

On the Staggered Crosswalks, pedestrians cross the crosswalks two times. This method can reduce the cycle, the vehicle delay and the walking distance by increasing the major direction of green time. The safety of pedestrians is also effective. This study suggests the warrant of the facilities of island width and length etc. by considering the road structure and pedestrians. Also this study suggests the standard of the safety through the accident analysis of Staggered crosswalks and General Crosswalks. In the results, accident rate of the Staggered Crosswalks 18.3(100 million vehicle-km) was lower than the accident rate of the General Crosswalks 28.3(100million vehicle-km). By understanding the start point of crossing of the Staggered Crosswalks, the analysis of the location and types of accident suggests the safety zone(spare space). The setting warrants of Staggered Crosswalks are 4 lane over the road and the 2 meter over sidewalk width of island. The minimum length of the Pedestrian island was doubled compared to the crosswalks width. And the maximum length was set by considering the wait time of the pedestrians.

• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.3
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• pp.227-236
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• 2010

This study was carried out in order to find out the growth characteristics, the seasonal anthesis distribution and the botanical composition of the wildflower pastures which were altogether composed of 90% sheep fescue and 10% wildflowers in the Chungnam National University experimental field from October, 2007 to December, 2009. The experimental species contained 34 species in total consisting of sheep fescue (fundamental turfgrass), 4 native wildflowers, and 29 induced wildflowers belonged. At the time of the anthesis of the wildflowers, the average length was 28.7 cm one year later and 36.7 cm two years later. They bloomed out into from six to nine colors, but into one or three colors during August, September, and October. The blooming season leant toward May and June, and from August, there was lots of difficulty in the wildflower blooming and the maintenance of their consistency. Especially, at the age of two (2009) the color, seasonal distribution, and consistency emerged as problems owing to the reduction of annual wildflowers after winterization. The annual botanical composition of wildflowers, sheep fescue, and weeds came to 22%, 68%, and 10% each one year later (2008) and 19%, 72%, and 9% each two years later (2009). Based on this result, cultivating wildflower in grassland (90% sheep fescue and 10% wildflowers) is the proper method not only for maintaining green space, to prevent soil erosion by sheep fescue, but also for commanding a fine view of wildflowers.

• Journal of The Korean Society of Grassland and Forage Science
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• v.31 no.3
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• pp.285-294
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• 2011

This study was carried out in the Chungnam National University grassland experimental field from October, 2007 to December, 2009 in order to find out the growth characteristics of the wildflowers, the seasonal anthesis distribution of the wildflowers, and the botanical composition of the wildflowers which were altogether composed of 70% sheep fescue and 30% wildflowers. The experimental species contained 34 species in total to which sheep fescue (fundamental turfgrass), 4 native wildflowers, and 29 introduced wildflowers belonged. At the time of the anthesis of the wildflowers, the average length was 29.9 cm one year later and 38.4 cm two years later. They bloomed out into nine colors, but into one or three colors during August, September, and October. The blooming season leant toward May and June and from August there was lots of difficulty in the wildflower blooming and the maintenance of their consistency. Especially, at the age of two (2009) the color, seasonal distribution, and consistency emerged as problems owing to the reduction of annual wildflowers after winterization. The annual ration of wildflowers, sheep fescue, and weeds came to 25%, 61%, and 14% each one year later (2008) and 22%, 65%, and 13% each two years later (2009). Based on this result, cultivating wildflower grassland in the ratio of 70% (sheep fescue) to 30% (wildflowers) is the proper method not only for maintaining green space by sheep fescue, but also for commanding a fine view of wild flowers.