• 한국표면공학회지
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• 제39권6호
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• pp.268-275
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• 2006

In this study, effect of sputtering on the plasma-nitriding substrate and before PVD coating on the microstucture, microhardness, surface roughness and the adhesion strength of CrZrN thin films were investigated. Experimental results showed that this sputtering process not only removed surface compound layer which formed during a plasma nitriding process but also induced an alteration of the surface of plasma nitrided substrate in terms of microhardness distribution, surface roughness. This in turn affected the adhesion strength of PVD coatings. After sputtering, microhardness distribution showed general decrease and the surface roughness became increased slightly. The critical shear stress measured from the scratch test on the CrZrN coatings showed an approximately 1.4 times increase in the adhesion strength through the sputtering prior to the coating and this could be attributed to a complete removal of compound layer from the plasma nitrided surface and to an increase in the surface roughness after sputtering.

• 대한통합의학회지
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• 제7권3호
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• pp.197-204
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• 2019

Purpose: The purpose of this study was to investigate the effects of the plank exercise to strengthen the core muscles on the muscle thickness of external and internal obliques and transverse abdominis muscle depending on the form of the support surface. Methods: This study was randomized to 12 males and 12 females in their 20s and conducted three times a week for 4 weeks. The subjects were divided into the two groups and performed flank exercise on a stable surface (stable surface group) and an unstable surface (unstable surface group). A mat was used as a stable surface, and an TOGU used as a unstable surface. Results : In both stable and unstable surface, the thickness changes of the transverse abdominis and external and internal oblique muscle increased (p<.05). In the unstable surface, there was a greater increase in the thickness change of the transverse abdominis and external oblique muscles in the flank exercise than in the stable surface (p.<05). Among them, the greatest increase was found in the external abdominal muscle (p<.05). Conclusion : This study found that the flank exercise was more effective in strengthening the abdominal muscles on an unstable surface, when compared with the outcomes on a stable one. It is also thought to have the most effect on the muscle activity of the external oblique muscle on unstable surface.

• 한국표면공학회지
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• 제52권1호
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• pp.37-42
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• 2019

Electrodeposited zinc layer is widely used as a sacrificial anode for a corrosion protection of steel. In this study, we modified the surface of electrodeposited zinc to have a hydrophobicity, which shows various advanced functionalities, such as anti-corrosion, anti-biofouling, anti-icing and self-cleaning, due to its repellency to liquids. Superhydrophobicity was realized on electrodeposited zinc layer with a hydrothermal treatment, creating nanostructures on the surface, and following Teflon coating. The superhydrophobic surface shows a great repellency to water with high surface tension, while liquid droplets with low surface tension easily adhered on the superhydrophobic surface. However, immiscible lubricant-impregnated superhydrophobic surface shows a great repellency to various liquids, regardless of their surface tension. Therefore, it is expected that the lubricant-impregnated surface can be an alternative of superhydrophobic surface, which have a drawback for some liquids with a low surface tension.

• 정보학연구
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• 제8권1호
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• pp.113-118
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• 2005

Investigation of surface discharge characteristics of surface leakage on polluted EPDM insulator have been performed. This work was performed utilizing High Frequency Current Trans former to monitor surface discharge. It was found that there were significant variation in the surface discharge waveform frequency spectrum, depending both on the surface discharge magnitude and more importantly on the duration of surface discharge activity.

• 한국생산제조학회지
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• 제4권3호
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• pp.48-57
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• 1995

The feasibility of generating controller surface topographies in single-point conventional turning operations is investigated. First, a mathematical model of the surface generation process was developed. Second, in order to control the texture of the machined surface, a micro-positioning stage and the associated command generation software were designed and built. Experimental examples have shown that surface texture can be precisely controlled and is in good agrement with the theoretical predictions.

• 한국환경과학회지
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• 제7권3호
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• pp.269-274
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• 1998

In order to develop of support medla for bloom reactor, physicochemical properties and attachability of surface of activated carbon, clay mineral, non-clay mineral, and waste mold sand were enamined. Measured physicochemical properties of materials were surface roughness, mean particle size, surface area, hydrophobicity, and surface charge. At a tested materials, activated carbon was the best attachable material and microorganisms were attached $20.1{\times}10^7CFU/cm^2$ at surface, compared with diatomaceous earth which were attached of $9.2{\times}10^7CFU/cm^2$ in our research, surface area and hydrophobicity show- ed more Influence than any other factor on attachment of microorganisms.

• 대한조선학회논문집
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• 제41권1호
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• pp.75-81
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• 2004

In this study surface modeling .method with 3D curve net is proposed. For surface modeling, ship hull was divided into several parts, Generated surface was loaded general purpose CAD program through IGES file format, and the quality of generated surface model was checked by CATIA's internal function. Lastly it is tried to find a method for improving the accuracy of surface connection by using the blending method in CATIA and the result was discussed.

• Journal of Mechanical Science and Technology
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• 제15권11호
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• pp.1541-1547
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• 2001

The non-dimensional fin length for optimum heat loss from a thermally asymmetric rectangular fin is represented as a function of the ratio of the bottom surface Biot number to the top surface Biot number, fin tip surface Biot number and the non-dimensional fin width. Optimum heat loss is taken as 98% of the maximum heat loss. For this analysis, three dimensional separation of variables method is used. Also, the relation between the ratio of the bottom surface Biot number to the top surface Biot number and the ratio of the right surface Biot number to the left surface Biot number is presented.

• 한국세라믹학회지
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• 제13권3호
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• pp.3-12
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• 1976

The corelation between surface tensions and surface appearances of SK O5a opaque glazes for earthen wares were investigated. The surface tension values were theoretically calculated by using Dietzel's factors of constituent oxides of glaze. The surface appearances of glazes, especially the pinhole phenomena were strongly effected by the surface tension values showing the following general tendencies: (1) In the range of 305±3 dynes/cm of surface tensions, glazes showed almost no pjnholes. (2) In the range of surface tensions less than 300 dynes/cm, the large numbers of small pinholes or eggshell textures were observed. (3) In the range of surface tensions higher than 310 dynes/cm, large and deep pinholes were observed. (4) The contact angles of glazes on the wall tile body substrate are in the good proportional agreement with the surface tension values calculated by Dietzel's factors.

• International Journal of Human Ecology
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• 제14권1호
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• pp.41-55
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• 2013

The purpose of this study was to analyze human upper body surface changes at the shoulder and back area. The body surface data were analyzed in terms of muscle and bone displacement in dynamic postures. Body surface data were collected with a 3D body scanner. The body surface was scanned at the static and four baseball batting postures. The body surface dimensions over the deltoids, scapulae and trapezius were measured. The results show that the vertical measurements of the deltoids increased by 20%. The horizontal measurements of the axilla of the back increased. The surface of the trapezius was elongated by over 10%, and the lower back musculature was elongated by about 50%. The results of this study showed that changes in back body surface caused by upper arm movements. It was influenced by the deltoid articulated with the humeri and the scapulae and trapezius. These body surface changes caused by muscle activities and ranges of motion can be used to design functional clothing.