• Korean Journal of Materials Research
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• v.14 no.2
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• pp.133-140
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• 2004

We carried out anodic aluminum oxide (AAO) on a Si and a sapphire substrate. For anodic oxidation of Al two types of specimens prepared were Al(0.5 $\mu\textrm{m}$)!Si and Al(0.5 $\mu\textrm{m}$)/Ti(0.1 $\mu\textrm{m}$)$SiO_2$(0.1 $\mu\textrm{m}$)/GaN(2 $\mu\textrm{m}$)/Sapphire. Surface morphology of Al film was analyzed depending on the deposition methods such as sputtering, thermal evaporation, and electron beam evaporation. Without conventional electron lithography, we obtained ordered nano-pattern of porous alumina by in- situ process. Electropolishing of Al layer was carried out to improve the surface morphology and evaluated. Two step anodizing was adopted for ordered regular array of AAO formation. The applied electric voltage was 40 V and oxalic acid was used as an electrolyte. The reference electrode was graphite. Through the optimization of process parameters such as electrolyte concentration, temperature, and process time, a regular array of AAO was formed on Si and sapphire substrate. In case of Si substrate the diameter of pore and distance between pores was 50 and 100 nm, respectively. In case of sapphire substrate, the diameter of pore and distance between pores was 40 and 80 nm, respectively

• Geomechanics and Engineering
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• v.37 no.2
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• pp.135-147
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• 2024

A GIS-based landslide susceptibility mapping (LSM) was carried out using frequency ratio (FR), modified frequency ratio (M-FR), analytic hierarchy process (AHP), and modified analytic hierarchy process (M-AHP) methods to identify and delineate the potential failure zones along the Halong - Vandon expressway. The thematic layers of various landslide causative factors were generated for modeling in GIS, including geology, rainfall, distance to fault, distance to road, slope, aspect, landuse, density of landslide, vertical relief, and horizontal relief. In addition, a landslide inventory along the road network was prepared using data provided by the management department during the course of construction and operation from 2017 to 2019, when many landslides were documented. The validation results showed that the M-FR method had the highest AUC value (AUC = 0.971), which was followed by the FR method with AUC = 0.961. The AUC values were 0.939 and 0.892 for the M-AHP and AHP methods, respectively. The generated LSM obtained from M-FR method classified the study area into five susceptibility classes: very low (0), low (0-1), moderate (1-2), high (2-3), and very high (3-4) classes, which could be useful for various stakeholders like planners, engineers, designers, and local public for future construction and maintenance in the study area.

• Journal of the Korea Organic Resources Recycling Association
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• v.10 no.3
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• pp.92-97
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• 2002

This study is to analyze collection factor of food wastes using GIS. For calculation of collection crews and equipment, It was measured velocity(43m/min), moving coefficient(1.9), moving distance(17,200/day), collection rate(0.313kg/day) on the basis of S2Dong. Moving coefficient was able to analyze straight distance of S2Dong using GIS and other areas were also applied to analyze straight distance of each area using same method. At N autonomous district, 10 persons of collection crews were necessary, but collection of food wastes by four forces resulted to be 11 persons of crews necessary. 7 vehicles were necessary, but 8 vehicles were needed by same reason.

• Applied Biological Chemistry
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• v.39 no.4
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• pp.260-264
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• 1996

Process of particle bombardment for efficient transformation of Cymbidium virescence rhizome microcross sections was investigated using Biolistic particle delivery system with pBI121 harboring the ${\beta}-glucuronidase$(GUS) and the neomycin phosphotransferaseII(nptII). The best result was obtained from the combination of $1.11{\;}{\mu}m$ tungsten particles coated with pBl121, $77.33kg/cm^2$ helium pressure, 6.35 mm gap distance, and 7.0 cm target distance. Transient expression of the reporter gene, GUS, bombarded into the rhizome microsections was observed by the histochemical assay. The marker gene, nptII, delivered by bombarding the tungsten particles coated with the plasmid DNA was identified in the transformed rhizome by polymerase chain reaction.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.31 no.4
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• pp.285-292
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• 2013

This study proposes a network matching method based on a network division technique. The proposed method generates polygons surrounded by links of the original network dataset, and detects corresponding polygon group pairs using a intersection-based graph clustering. Then corresponding sub-network pairs are obtained from the polygon group pairs. To perform the geometric correction between them, the Iterative Closest Points algorithm is applied to the nodes of each corresponding sub-networks pair. Finally, Hausdorff distance analysis is applied to find link pairs of networks. To assess the feasibility of the algorithm, we apply it to the networks from the KTDB center and commercial CNS company. In the experiments, several Hausdorff distance thresholds from 3m to 18m with 3m intervals are tested and, finally, we can get the F-measure of 0.99 when using the threshold of 15m.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.4 s.119
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• pp.455-463
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• 2007

In this paper, it is proposed how to implement the object detection system which is able to apply to vehicular applications, unmanned facilities, automatic door and others with microwave. As the technology which detects an object with microwave is becoming more popular, it seems impossible to avoid mutual interference and jamming caused by limited frequency bandwidth. The system in this paper detects an object by correlating the code of TX and RX signals with the pseudo-random code having best quality in interference and jamming environment. In order to generate simulant doppler signal for detecting the distance of an fixed object where there is no doppler effect, the phase of TX signal is shifted continually. Also, the saturation of receiver was removed and the error of distance measurement was decreased by controlling the power of TX signal for getting constant RX signal. The proposed system detects a object which ranges from 0.5 m to 2.0 m and informs vocally whether there is the object within 1.0 m or not.

• Journal of the Korean Society of Safety
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• v.36 no.4
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• pp.71-79
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• 2021

In this study, a real-scale fuel-cell room of volume 1.36 m³ is constructed to confirm the explosion characteristics of hydrogen-air mixture gas in a hydrogen-powered house. A volume concentration of 40% is applied in the fuel-cell room as the worst-case scenario to examine the most severe accident possible, and two types of doors (made of plastic sheet and wood) are fabricated to observe their effects on the overpressure and impulse. The peak overpressure and impulse based on distance from the ignition source are experimentally observed and assessed. The maximum and minimum overpressures with a plastic-sheet door are about 20 and 6.7 kPa and those with a wooden door are about 46 and 13 kPa at distances of 1 and 5 m from the ignition source, respectively. The ranges of impulses for distances of 1-5 m from the ignition source are about 82-28 Pa·s with a plastic-sheet door and 101-28 Pa·s with a wooden door. The amount of damage to people, buildings, and property due to the peak overpressure and impulse is presented to determine the safe distance; accordingly, the safe distance to prevent harm to humans is about 5 m based on the 'injuries' class, but the structural damage was not serious.

• The Journal of the Acoustical Society of Korea
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• v.38 no.3
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• pp.352-362
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• 2019

The old residences and shops in the backside blocks are affected by the traffic noises from the main road. The noise of the backside roads is affected by the following factors such as the height of the roadside buildings, the distance between the road and the backside streets, distance among adjacent roadside buildings, and the difference of the adjacent building heights. The both noise levels on the road and the backside street were measured simultaneously in 15 urban blocks of a city which can be categorized into two types of roadside building plans ; 1) one single building along the street, 2) buildings arranged on one axis beside the road. As the results, there is no significant noise reduction due to the width of the buildings in general. However, in the cases of buildings arranged on one axis beside the road, it was found that the average noise reduction was 12 dB(A) on the basis of the building height of 4 m. Also, it was analysed that for each 4 m increase in the building height, noise reduction occurred by 2 dB(A) beyond building height of 4 m. In general, it was proved that the noise of the back streets is mainly affected by the lowest height of the roadside buildings. It was found that noise is increased by 1 dB(A) for each 4 m increase of the height difference between adjacent buildings. Also, It was revealed that for each 0.5 m increase in the distance between roadside building, noise reduction decreased by 1 dB(A).

• Korean Journal of Ichthyology
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• v.13 no.1
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• pp.19-23
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• 2001

The full-grown oocyte envelope of the two spined loaches, Niwaella multifasciata and Kichulchoia brevifasciata, was examined by electron microscopy. The oocyte is surrounded by its envelope, and an external modification (an adhesive structure) in the surface of the envelope is present. The envelope consists of two layers, a zona radiata externa which is the site of the adhesive structure, and a zona radiata interna, which has heterogeneous, electron-dense multi layers. The surface (zona radiata externa) of the envelope in N. multifasciata is equipped with short villuslike protuberances, which have a length of 1.5~2.5 ${\mu}m$ and are separated from each other by a distance of 2~2.5 ${\mu}m$. In contrast, K. brevifasciata has undulating or wave-like structures that extend over the entire oocyte surface. The waves are 1.5~2.5 ${\mu}m$ in length and are separated a distance of 2.5~3.3 ${\mu}m$ from each other.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.2
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• pp.193-215
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• 2022

Recently, ground structures have reached saturation, and underground construction using underground structures such as tunnels has been in the spotlight as a way to solve increasing traffic difficulties and environmental problems. However, due to the increasing number of underground structures, close construction is inevitable for continuous underground development. When a new underground structure is constructed closely, stability may become weak due to the influence on the existing tunnel, which may cause collapse. Therefore, analyzing the stability of existing tunnels due to new structures is an essential consideration. In this study, the effect of excavating new tunnels under parallel tunnels on existing parallel tunnels was analyzed using numerical analysis. Using the Displacement Control Model (DCM), the volume loss generated during construction was simulated into three case (0.5%, 1.0%, and 1.5%). Based on the center of the pillar, the distance where the new tunnel is located was set to 5 m, 6 m, 7 m, 8 m, 9 m, and the space for each distance were set to 5 (0D₁, 0.37D₁, 0.75D₁, 1.13D₁, 1.5D₁). In general, as the volume loss increased and the distance approached, the maximum displacement and angular displacement increased, and the strength/stress ratio to evaluate the stability of the pillar also decreased. As a result, when the distance between the new tunnel and the center of the pillar is 5 m, the space is 0D₁, and the volume loss is 1.5%, the stability of the existing parallel tunnel is the weakest.