• Tribology and Lubricants
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• 제30권6호
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• pp.350-355
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• 2014

This study proposes a sustainable bearing remanufacturing process using the ultrasonic nanocrystal surface modification (UNSM) technique. The UNSM technique is a newly developed and sophisticated surface modification technique that can increase the mechanical properties and improve the friction and wear performance of materials. Taking advantage of the bearing manufacturing process is the most significant way of optimizing the life of a bearing. The proper maintenance and usage of repaired bearings can increase their life to be equal to or greater than that of new bearings. This paper discusses the restoration of certain mechanical properties of worn, damaged, and discarded bearings, and suggests a remanufacturing process for used bearings, which can impart them with a lifespan equivalent to that of new bearings. The most damaged part of the discarded bearings is the raceway, which is the site of accumulated fatigue. The existing polishing or barrel finishing processes can recover the accumulated fatigue only partially. Rolling contact fatigue tests performed on UNSM-treated new and used specimens polished after $4{\times}10^6$ cycles reveal that UNSM-treated new specimens exhibit the longest fatigue life compared to other specimens. This study verifies the proposed complete fatigue recovery process, which can increase the fatigue life of used bearings to a level greater than that of new bearings.

• 한국염색가공학회지
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• 제20권2호
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• pp.19-28
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• 2008

The objective of this study was to apply the statistical technique known as design of experiments to optimize the % exhaustion variables for phthalocyanine dyeing of nylon fiber. In this study, a three-factor Central Composite Rotatable Design (CCRD) was used to establish the optimum conditions for the phthalocyanine reactive dyeing of nylon fiber. Temperature, pH and liquor ratio were considered as the variable of interest. Acidic solution with higher temperature and lower liquor ratio were found to be suitable conditions for higher % exhaustion. These three variables were used as independent variables, whose effects on % exhaustion were evaluated. Significant polynomial regression models describing the changes on % exhaustion and % fixation with respect to independent variables were established with coefficient of determination, R2, greater than 0.90. Close agreement between experimental and predicted yields was obtained. Optimum conditions were obtained using surface plots and Monte Carlo simulation techniques where maximum dyeing efficiency is achieved. The significant level of both the main effects and interaction was observed by analysis of variance (ANOVA) approach. Based on the statistical analysis, the results have provided much valuable information on the relationship between response variables and independent variables. This study demonstrates that the CCRD could be efficiently applied for the empirical modeling of % exhaustion and % fixation in dyeing. It also shows that it is an economical way of obtaining the maximum amount of information in a short period of time with least number of experiments.

• 한국실내디자인학회논문집
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• 제16권5호
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• pp.98-106
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• 2007

With the recent increase in the amount of interior materials, the medium-density fiberboard(MDF) has continued to be produced at an increasing rate. Accordingly, to prevent the deformation of MDF after its construction, secure the precision of its finishing and improve the performance of its design, this study attempted to investigate the effect of environment humidity conditions on flatness according to the field used in MDF and its relationship to other physical properties. An attempt was made to conduct this study by changing the conditions of surface treatment by moisture and by thickness. For this purpose, it is judged that it is desirable to prevent scheme to maintain the flatness by defining the coefficient of water absorption-induced length change as in the regulation on low-density soft fiberboard and adjusting the standard for wet bending strength upward. It is thought that is further studies will be conducted about the effect of material, adhesive and thermal pressure condition, production system and processing method used in MDF on its scheme to maintain the flatness and changes in length and thickness expansion.

• 한국농촌건축학회논문집
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• 제16권1호
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• pp.87-94
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• 2014

The objective of this study is to provide a townscape design guideline that harmonized with a historic landscape via condition investigation and landscape analysis of the cultural /commercial environment district where an improvement is a necessity. The followings are the conclusions: 1.To enhance the identity of Gyeongju, should pursue diversity in unity by making the image of architectural landscape a similar peculiarity. 2.The central commercial district where the tradition is valued and contemporary figures meet the tradition needs a landscape formation by CONTEXT. 3.Since a characteristic of the target area is a regional commercial center, to reduce its congestion, reforming the area to simple environment is required. 4.Induce buildings located on the streets with cultural properties to have Korean traditional tiled roof in order to fit in with their surroundings. 5.Make it a rule to partition a wall into tripartition, the wall surface exposed should be the same finishing materials. 6.Consider the visual aspect of pedestrians and a building's width, the recommendable height of the facade should be 3~3.6m. 7.For the design archetype of cornice, four traditional types based on Korean traditional eaves are suggested. 8.The design of signboards should break existing square-shapes, and seek a design to take advantage of icons that historicity and traditionalist of the city are expressed.

• 한국레이저가공학회지
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• 제12권4호
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• pp.12-16
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• 2009

The engineering ceramic is one of the materials advantageous in various conditions with high strength, endurance at high temperature, abrasion resistance and corrosion resistance, etc. However, due to high strength and high brittleness, ceramic incurs high costs and long time on finishing process required after sintering. So a process for obtaining wanted measurements of them has been studied using the high temperature which makes ceramics softened and heat affected recently. This study makes an estimate of laser-assisted machining (LAM) if an economically practical process for manufacturing precision silicon nitride ceramic parts using laser beam. In this study, mechanical properties of silicon nitride at high temperature were observed. And during the LAM, it was observed that cutting force and tool wear were reduced and oxidation of machined surface was increased according to a increase of laser power.

• 한국염색가공학회지
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• 제23권2호
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• pp.118-130
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• 2011

In this study, hydrophilic polyurethane (PU) was synthesized by one shot process to get good non-swelling effect and to keep high breathability using reactive silicone oil of mono terminal and bi-terminal types. We also blended non reactive silicone oil with pure hydrophilic PU to compare non-swelling effect and breathability with hydrophilic PU synthesized by the two types of reactive silicone oils. The hydrophilic films were analyzed by nuclear magnetic resonance (NMR) spectroscopy, scanning electron microscope (SEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray photo electron (XPS) spectroscopy, energy dispersive spectrometry (EDS), breathability, waterproofness, tensile strength, contact angle and swelling effect. The results showed that the film made by hydrophilic PU which was synthesized with mono terminal type silicone oil provided good non-swelling effect and acceptable moisture permeability due to the modified surface properties.

• 한국염색가공학회지
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• 제18권6호
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• pp.69-79
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• 2006

The washing characteristics of steam jet heating process have been compared with other washing processes, such as low temperature process(standard process, below $40^{\circ}C$) and high temperature process(boiling process, up to $95^{\circ}C$) with the standard soil fabric, EPMA 105. Steam jet heating process showed almost the same washing efficiency as high maximum temperature process for pig's blood and wine. This result can be explained with the higher surface temperature of washing materials in steam jet process compared with direct boiling process. In terms of the energy and water consumption, the steam jet washing process showed significant savings compared with direct boiling type washing process.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2009년도 춘계학술대회 논문집
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• pp.129-134
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• 2009

학교 조명실태를 조사하고 교실 1실에 설치된 조명기구의 수량별로 분류하고, 분류된 형태별로 조도를 측정하여 조도실태를 분석하였다. 책상면 조도는 학교시설기준을 만족하나 칠판용 국부조명을 설치하지 않은 경우 칠판조도가 학교시설기준에 미치지 못하였다. 교실 마감재 반사율 측정과 램프교체 및 램프청소 실험 등 실제로 측정한 자료를 기초로 하여 시뮬레이션 한 결과 현실적으로 전반조명 9등과 칠판용 국부조명이 필요하였으며, 유지관리를 고려한 설계가 요구됨을 알 수 있었다.

• 조명전기설비학회논문지
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• 제23권6호
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• pp.14-23
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• 2009

학교 조명실태를 조사하고 교실 1실에 설치된 조명기구의 수량별로 분류하고, 분류된 형태별로 조도를 측정하여 조도실태를 분석하였다. 책상면 조도는 학교시설기준을 만족하나 칠판용 국부조명을 설치하지 않은 경우 칠판조도가 학교시설기준에 미치지 못하였다. 교실 마감재 반사율 측정과 램프교체 및 램프청소 실험 등, 실제로 측정한 자료를 기초로 하여 시뮬레이션한 결과 현실적으로 전반조명 9등과 칠판용 국부조명이 필요하였으며, 유지관리를 고려한 설계가 요구됨을 알 수 있었다.

• 한국염색가공학회지
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• 제32권4호
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• pp.265-273
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• 2020

In this study, octadecyldimethyl(3-triethoxy silylpropyl)ammonium chloride (ODDMAC) incorporated with Polyethylene terephthalate (PET) fabrics with different environmental conditions such as various temperature and time intervals. First, ODDMAC (15 weight %) was dissolved in ethanol. Then PET fabrics immersed in the ODDMAC solution at 25 ℃ for 10 minutes and dried at 80 ℃ for 5 minutes. The dried PET/PDDMAC fabrics carried out for curing process out at 110 ℃ ~ 190 ℃. The treated PET/ODDMAC has examined the surface and side coating properties through SEM analysis and elemental analysis. PET/ODDMAC fabric washed with water up to 50 times and studied the durability of the materials. It was confirmed that the treated PET fabric also exhibited good water repellency. In addition, the antimicrobial activity against the gram-positive bacteria Staphylococcus aureus and gram-negative bacteria Escherichia coli were studied by the disc diffusion method on the treated fabric.