• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1166-1169
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• 2003

The issue with the drainpipe now a day is that they are laid underground Causing us to perform additional work to repair, such as digging up the ground and peeling off the insulator that surrounds the pipe. And such series works are difficult that concession appears from government and municipal office. However, if we can save time and money. Performance of piping robot that we are studied in existing session through fixing unit and improvement of cutting byte shorten and wished to heighten work efficiency. This is why we aye trying to develop a unit that can cut up the projecting parts which connects with the interior part of the drainpipes.

• International Journal of CAD/CAM
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• v.6 no.1
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• pp.105-115
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• 2006

Thickness is a commonly used parameter in product design and manufacture. Its intuitive definition as the smallest dimension of a cross-section or the minimum distance between two opposite surfaces is ambiguous for intricate solids, and there is very little reported work in automatic computation of thickness. We present three generic definitions of thickness: interior thickness of points inside an object, exterior thickness for points on the object surface, and radiographic thickness along a view direction. Methods for computing and displaying the respective thickness values are also presented. The internal thickness distribution is obtained by peeling or successive skin removal, eventually revealing the object skeleton (similar to medial axis transformation). Another method involves radiographic scanning along a viewing direction, with minimum, maximum and total thickness options, displayed on the surface of the object. The algorithms have been implemented using an efficient voxel based representation that can handle up to one billion voxels (1000 per axis), coupled with a near-real time display scheme that uses a look-up table based on voxel neighborhood configurations. Three different types of intricate objects: industrial (press cylinder casting), sculpture (Ganesha idol), and medical (pelvic bone) were used for successfully testing the algorithms. The results are found to be useful for early evaluation of manufacturability and other lifecycle considerations.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.7-8
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• 2017

Corrosion of reinforced concrete embedded in concrete is a deterioration phenomenon due to intrusion of embodied or Airborne chloride ions. Corrosion of a embedded steel increases the volume of the rebar and causes damage to the structure such as cracking and peeling of the concrete. This causes penetration of various corrosive factors and accelerates the corrosion of reinforcing bars, which has a serious effect on the durability of the structure. Researches on the corrosion phenomenon of these rebars by electrochemical methods have been carried out for a long time, but it is a lack of research in Korea. Therefore, in this study, one of electrochemical experimental methods, Tafel extrapolation method, was used to evaluate the performance of reinforcing bars according to the amount of NaCl and LiNO₂ added to concrete.

• Korean Journal of Medicinal Crop Science
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• v.24 no.5
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• pp.351-359
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• 2016

Background: We investigated the optimal aqueous extraction conditions for recovery of high yields of total phenolic compounds from roots of Arctium lappa L. (burdock, Asteraceae), and we compared their antioxidant capacity. Methods and Results: The antioxidant activity of the extracts was tested using 2,2-diphenyl-1-picrylhydrazyl, 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)-diammonium salt, and oxygen radical absorbance capacity assays. In addition, the major phenolic compounds present in the extracts were determined by high performance liquid chromatography analysis. Our results suggest that the roasted burdock $100^{\circ}C$, 15 min extract exhibited the strongest radical scavenging activity and possessed the highest concentration of phenolic compounds. The polyphenol content of both dried burdock and roasted burdock significantly increased with increase in the extraction temperature and time. Conclusions: These results indicated a relationship between phenolic compound levels in burdock and their free radical scavenging activities. This suggests that phenolic compounds significantly increase the antioxidant potential of burdock extracts.

• 한국HCI학회:학술대회논문집
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• 2007.02c
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• pp.326-333
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• 2007

To simulate solid dynamics,a we must com-pute the mass, the center of mass, and the products of inertia about the axes of the body of interest. These mass property computations must be continuously re-peated for certain simulations with rigid bodies or as the shape of the body changes. We introduce a GPU-friendly algorithm to approximate the mass properties for an arbitrarily shaped body. Our algorithm converts the necessary volume integrals into surface integrals on a projected plane. It then maps the plane into a frame-buffer in order to perform the surface integrals rapidly on the GPU. To deal with non-convex shapes, we use a depth-peeling algorithm. Our approach is image-based; hence, it is not restricted by the mathematical or geometric representation of the body, which means that it can efficiently compute the mass properties of any object that can be rendered on the graphics hardware. We compare the speed and accuracy of our algorithm with an analytic algorithm, and demonstrate it in a hydrostatic buoyancy simulation for real-time applications, such as interactive games.

• Korean Journal of Materials Research
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• v.33 no.4
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• pp.115-123
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• 2023

In this paper, we report and discuss the semi-permanently hydrophilic (SPH) treatment of polyester fabric using plasma polymerization and oxidation based on atmospheric pressure dielectric barrier discharge (APDBD) technology. SiO_xC_y(-H) was coated on polyester fabric using Hexamethylcyclotrisiloxane (HMCTSO) as a precursor, and then plasma oxidation was performed to change the upper layer of the thin film to SiO₂-like. The degradation of hydrophilicity of the SPH polyester fabrics was evaluated by water contact angle (WCA) and wicking time after repeated washing. The surface morphology of the coated yarns was observed with scanning electron microscopy, and the presence of the coating layer was confirmed by measuring the Si peak using energy dispersive x-ray spectroscopy. The WCA of the SPH polyester fabric increased to 50 degrees after 30 washes, but it was still hydrophilic compared to the untreated fabric. The decrease in hydrophilicity of the SPH fabric was due to peeling of the SiO_xC_y(-H) thin film coated on polyester yarns.

• Journal of Periodontal and Implant Science
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• v.40 no.6
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• pp.276-282
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• 2010

Purpose: The present study was performed to evaluate the effect of erbium:yttrium-aluminium-garnet (Er:YAG) laser irradiation on the change of hydroxyapatite (HA)-coated implant surface microstructure according to the laser energy and the application time. Methods: The implant surface was irradiated by Er:YAG laser under combination condition using the laser energy of 100 mJ/pulse, 140 mJ/pulse and 180 mJ/pulse and application time of 1 minute, 1.5 minutes and 2 minutes. The specimens were examined by surface roughness evaluation and scanning electron microscopic observation. Results: In scanning electron microscope, HA-coated implant surface was not altered by Er:YAG laser irradiation under experimental condition on 100 mJ/pulse, 1 minute. Local areas with surface melting and cracks were founded on 100 mJ/pulse, 1.5 minutes and 2 minutes. One hundred forty mJ/pulse and 180 mJ/pulse group had surface melting and peeling area of HA particles, which condition was more severe depending on the increase of application time. Under all experimental condition, the difference of surface roughness value on implant surface was not statistically significant. Conclusions: Er:YAG laser on HA-coated implant surface is recommended to be irradiated below 100 mJ/pulse, 1 minute for detoxification of implant surface without surface alteration.

• Journal of the Korea Institute of Building Construction
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• v.3 no.1
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• pp.107-114
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• 2003

This study aims to find methods that prevents aging of buildings paint coating and that limits defects in construction. Defects in painting can occur in four stages: pure paint, during painting, after the paint coating has dried, and after some period of time has passed after coating. Paint may become bad due to precipitation of pigments, formation of membranes, and seeding during manufacturing. Therefore, it is important that the paint is well mixed and kept airtight at a cool, dark place. Indents, paint brush strokes, orange peel, separation of colors, and paint running and spreading during the paint work process can be prevented by using high quality materials and applying a high-level of construction method. After the paint coating has dried, boiling, yellowing, poor drying, poor bonding, and/or glen deficiency may occur. These are influenced by the levels of cleanness of the dried product, drying temperature and hydration. Then, when the coating has been left dried for some period of time, cracking, peeling, scaling, swelling, discoloring, and/or rusting may develop due to the ultraviolet and contaminants in the air. Since these defects occur due to inappropriate construction schedule and/or hot and humid condition, one must use weatherproof materials. Furthermore, poor paint color may be caused by contamination in the sample plate, discoloration, and/or discrepancies in colors which are due to material differences, level of glossiness, degree of dispersion, dual color property of metallic colors, precipitation of pigments, etc. One should achieve reduction in construction cost and effectiveness in paint work by limiting contaminations in the construction site and strictly observing to construction regulations.

• Fashion & Textile Research Journal
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• v.13 no.3
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• pp.438-444
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• 2011

Bamboo leaves, as natural dye provide unartificial fresh green, are known for expert property at anti-bacterial, anti-aging, anti-oxidation, skin whitening, moisturizing, peeling of horny, deodorizing and some skin disease like as eczema and inflammation without any allergic response. Also, It is quite common to obtain bamboo leaves from our surrounding but most of them were not in use. On purpose of development the way of recycle with common material to dye, bamboo leaves were used to dye on ramie fiber which is valuable for both of apparel and industrial field and investigated their dyeing property. Using extract from bamboo leaves, dyeing property was examined with dyeability, colorimetric property, light fastness and wash fastness under different conditions by extract density, dyeing time, dyeing method and mordants. As results, dyeing was generally colored in yellowish, K/S Value was shown more higher on hemp fiber than ramie. The most optimum dyeing condition was investigated on pre-mordant treatment, dyeing temperature $60^{\circ}C$, dyeing time 30min and extract density 400%. On the treatment with mordant(Al, Fe, Cu), dyebility on both of hemp and ramie fiber were increased by mordant. Especially with Copper(Cu) as mordant, dyebility was highly increased than any other mordants and dyeings showed in deep color. Also on the fastness test which is the most important to natural dyeing, wash-fastness showed good performance with 4-5 grade but light-fastness was above 4 grade on both of hemp and ramie fiber, lower than wash-fastness overall.

• Journal of Surface Science and Engineering
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• v.52 no.6
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• pp.316-320
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• 2019

The effect of boronizing on mechanical properties including wear behavior and hardness of Inconel 625 superalloy were investigated. The cross-section observation demonstrated that boronized samples were composed of multi-phase boride layer (Cr_xB_x, Ni₂B), diffusion layer, and substrate. The boride and diffusion layers were increased with increasing treatment temperature and holding time. However, Cr_xB_x layer was partially peeled off when it treated 1000℃. Subsequently, boride layer was completely separated from substrate with increasing temperature and time. A partial peeling of Cr_xB_x layer is not noticeably degraded mechanical properties. In particular, friction coefficient and wear resistance were enhanced in lack of Cr_xB_x phase. Therefore, these results suggest that a Ni₂B phase mainly contribute to wear behavior on boronized Inconel 625 superalloy.