• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.4
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• pp.87-96
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• 2007

In this study, a Ridge Distinction Program was developed to improve the elevation standard, which is one of standards for mountainous districts conversion permission regulated by the Management of Mountainous Districts Act. To distinguish mountainous districts from other land types, this program assumed that the lower end of the mountainous districts is the outlet points where catchment size is 30ha. Also the program used the halfway line between the ridge and the lower end of the mountainous districts to recognize the upper slope areas. To prevent potential errors within the classification process, the areas that were classified as non-mountainous districts by the current forest type map were removed. According to the classification results by using the developed program, the 58% of the mountainous districts ($696,300m^2$) was classified into the upper slope area, while the only 3% of the mountainous districts ($30,956m^2$) were classified by adopting the current standards for the mountainous districts conversion permission. This result shows that the size of the upper slope areas tends to be altered by the standards defining the area. Therefore, for better acceptance of the Ridge Distinction Program in the associated fields, it is necessary to prove the effectiveness of the program and to revise the current standards for the mountainous districts conversion permission.

• Journal of Energy Engineering
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• v.15 no.2 s.46
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• pp.96-106
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• 2006

Among several different hydrogen production technologies, solar hydrogen system for water splitting is the only clean and sustainable energy supplier. Hydrogen production by water-splitting utilizing solar energy has attracted considerable interest since the pioneering work of Honda and Fujishima in 1979, who discovered that water can be photo-electrochemically decomposed into hydrogen and oxygen using a semiconductor ($TiO_2$) electrode under UV irradiation. Most efforts to utilize solar ray lead to explore visible responding photocatalysts, PEC cells and other fusion technology like bio-photocatalytic conversion. In this paper, photon utilization technologies for water splitting have been briefly reviewed except solar thermal utilization technology.

• Journal of the Korean Solar Energy Society
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• v.35 no.3
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• pp.65-71
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• 2015

A solar thermal simulator is suitable for indoor experiments of solar receivers and reactors when solar insolation and weather conditions are not favorable. Moreover, due to the easy control of electric power input, the solar thermal simulator allows the adjustment of power input incident on solar receivers and reactors and thus the implementation of accurate experiments. We manufactured a solar simulator, which is comprised of three sets of a xenon lamp and an elliptical reflector. In order to serve as a test facility, optical characterization of the solar simulator via radiation heat flux measurement is a critical prerequisite. We applied the flux mapping method to measuring the heat flux distribution of the three lamps. We presented the measurement results in terms of the heat flux distribution, the peak heat flux, the power distribution, the maximum power, and the efficiency for electric power conversion into radiation power. Characterization results show that our solar simulator provides the peak heat flux of $3,019kW/m^2$, the maximum power of 16.9 kW, and the conversion efficiency of 45%, additionally with a 10% operation margin for output increase.

• Journal of Power Electronics
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• v.1 no.2
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• pp.78-87
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• 2001

A new high-power step-up based on the two-module parallel-input (PISO) modular dual inductor-fed push-pull converter is proposed. The proposed converter is operated at a constant duty cycle and employs and auxiliary circuit to control the output voltage with a phase-shift between two modules. It shows a high efficiency due to the greatly reduced switch turn-off stress. It also shows a high and linear voltage conversion ratio, low current stress in the output capacitor, and fast control-to-output dynamics. The operation principles and the mathematical models of the proposed converter are presented. Features of the proposed converter are discussed in comparison with the two-module PISO modular dual inductor-fed push-pull converter. Also, experimental results from a 50kHz, 800W, 350 Vdc prototype with an input voltage range of 20-32 Vdc are provided to confirm the validity of the proposed converter. The new converter compares favorably with the conventional counterpart, and is considered well siuted to high-power step-up applications.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.708-715
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• 2017

Recently, in order to meet the stricter emission regulations, the proportion of after-treatments for vehicles and vessels has been increasing gradually. The objective of this study is to investigate the improvement of $CH_4$ reduction ability of natural gas oxidation catalyst (NGOC), which reduces toxic gases emitted from CNG buses. Thirteen NGOCs were prepared, and the conversion performance of noxious gases according to the type of supports, the loading amount of noble metal, and surfactant and aging were determined. Support Zeolite supported on No. 3 $NGOC(1Pt-1Pd-3MgO-3CeO_2/(46TiO_2+23Al_2O_3+23Zeolite)$ is an anionic alkali metal/earth metal component that improved the oxidation reactivity between CO and NO and noble metal dispersion, and thus enhanced the $CH_4$ reduction ability. As the loading amount of Pd, a noble metal with a high selectivity to $CH_4$, was increased, the number of reaction sites was increased and the ability to reduce $CH_4$ was improved. No. 11 $NGOC(1Pt-1Pd-3MgO-3CeO_2/(Z20+Al80)$(pH=8.5), to which nitrate surfactant had been added, exhibited well dispersed catalyst particles with no agglomeration and improved the $CH_4$ reduction ability by 5-15%. The $NGOC(2Pt-2Pd-3Cr-3MgO/90Al_2O_3)$(48h aging), which was mildly thermal aged for 48h, increased the $CH_4$ reduction ability to about 10% or less as compared with No. 12 NGOC(Fresh).

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.29 no.2
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• pp.397-405
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• 1999

Purpose: To clarify the usefulness and the limitation of Digora system/sup (R)/ by evaluating the physical characteristics as the quantitative image on Image Plate(Ip). Materials and Methods: Radiograms were taken by Heliodent MD(Siemens Co.. Germany) with the image plate for adult. Cu-step wedge as reference material. and three pieces of dry mandibular bone. Image analysis was performed by single color enhancement. density measurement with histogram. The relationship between the exposure conditions and the distribution of the pixel values of the image. the variation of pixel values of each step of Cu-step wedge at two different area and Cu-equivalent value of three pieces of dry mandibular bone measure by the conversion equation. Results: There was no linear relationship between the exposure condition and the average pixel value of the image. of which the distribution was not even. The pixel value differences between the center portion and the periphery were ranged from 60 to 70 in vertical plane and from 15 to 26 in horizontal plane. Two plot profile formed at two different areas of the Cu-step wedge were different. The measured Cu-equivalent values showed the discrepancy among the times of measurement. Conclusion: As above results. Image Plate(Ip) of Digora system/sup (R)/ showed the limitation as the quantitative image. The physical property of IP was expected to need to be compensated for the quantitative evaluation of the bone or others

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.2
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• pp.91-96
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• 2003

In Korean folk medicine, several herbs, Glycyrrhizae Radix, Persicae Semen, Salviae Radix, Angelicae Gigantis Radix, Zanthoxyli Fructus, Ginseng Radix Alba, Cnidii Rhizoma, and Carthami Flos, are known to enhance blood circulation and have wound healing or anti-inflammatory effects. These pharmacological actions prompted us to investigate whether these herbs might stimulate hair growth. Thus, using a mixture of their extracts called SPELA 707, we investigated their effects and found that SPELA 707 possessed significant hair cycle converting activity from the telogen phase to the anagen phase in C3H mice. Furthermore, we found that SPELA 707 enhanced the hair density in subjects with hair loss and also promoted the conversion of hair into the anagen phase in subjects with androgenetic alopecia. In addition, hair growth promotion effect of SPELA 707 occurred through inhibition of steroid $5{\alpha}$-reductase activity, which is known to block hair growth. Taken together, these results suggest that SPELA 707 has a potential to be used for the treatment of hair loss.

• International Journal of Naval Architecture and Ocean Engineering
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• v.12 no.1
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• pp.116-128
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• 2020

In the shipbuilding industry, three-dimensional (3D) templates play a key role in the completeness evaluation of shell plates with a large curvature in the shell-plate fabrication process. Currently, the information of 3D templates from a ship computer-aided design system is limited; thus, manufacturers depend on their experience to produce the templates manually. This results in the inaccuracy of templates in addition to increased production time. Therefore, if the pieces of the 3D templates can be produced automatically with accurate information, the lead time of the fabrication process can be reduced. In this study, we define a new type of template piece and develop methods for extending a boundary template and converting manufacturing information into numerical control machine input. In addition, based on the results of the study, we propose a production automation system for 3D template pieces. This system is expected to reduce the lead time of the fabrication process.

• Journal of the Korean Solar Energy Society
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• v.30 no.6
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• pp.89-94
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• 2010

A large portion of the energy cost of a building is cooling and heating to maintain a comfortable indoor environment. Air conditioning is now one of the important parts in the building design, as increase in energy consumption and pollutant emission in energy conversion process. In this study, elements that affects the energy consumption of model building are identified and the perfomance analysis of the alternative a Low Energy Cooling Systems considering characteristics of model building and energy saving performance is analyzed. In this study, elements that affect the energy consumption of office building are identified and energy saving performance of the alternative air conditioning system is analyzed. As a result, applied to earn and suggest basic data for energy saving measures. In this study, EnergyPlus simulation program was used to evaluate the energy load when alternative Low Energy Cooling Systems are applied to the model building. The reliability of simulation program is verified by comparing actual energy load from operation data of building management office and predicted energy load using simulation program. For Low Energy Cooling System application which considers the purpose and characteristics of the building, reasonable and energy-saving air conditioning method obtained by analyzing energy consumption elements for each expected air conditioning methods is used to deduct result of this study.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.47-48
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• 2023

In the domestic industrial sector, greenhouse gases emitted from the cement industry account for about 10%, with most of them generated during the cement clinker calcination process. During the calcination process, 57% of carbon dioxide is emitted from the decarbonation reaction of limestone, 30% from fuel consumption, and 13% from electricity usage. In response to these issues, the cement industry is making efforts to reduce carbon dioxide emissions by developing technologies for raw material substitution and conversion, improving process efficiency by utilizing low-carbon alternative heat sources, developing CO₂ capture and utilization technologies, and recycling waste materials. In addition, due to the limitations in purchasing and storing industrial byproducts generated from industrial facilities, many studies are underway regarding the recycling of construction waste. Therefore, this study analyzes the manufacture of calcium silicate cement (CSC), which can store carbon dioxide as carbonate minerals in industrial facilities, and aims to contribute to the development of environmentally friendly regenerated cement using construction waste.