• Journal of Welding and Joining
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• v.19 no.2
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• pp.191-199
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• 2001

The oxidation and recrystallization behaviors of Ni-base single crystal superalloy, CMSX-2 were investigated to determine the condition of the preparation for transient liquid phase (TLP) bonding operations. The faying surfaces of CMSX-2 were worked by the shot peening, fine cutting and mechanical polishing treatments and the degree of working of treated surfaces was evaluated by the hardness test and X-ray diffraction method CMSX-2 was heat-treated at 1,173∼1.589k for 3.6ks in vacuum of 4mPa. The mechanically polished surface was slightly oxidized after heat treatment even in the vacuum atmosphere of 4mPa. The thickness of an oxide film increased with increasing the heating temperature and the surface roughness of the faying surface. Recrystallization occurred at the surface after heat treatment at above 1,423K when the hardness was increased more than Hv600 by the shot peening treatment while the mechanically polished or fine cut surfaces didn't recrystallized. Based on these results, it was clearfied that the mechanically polishing with fine abrasive grit could be used for the preparation of faying surface of CMSX-2 before bonding operation.

• Journal of the Korean Home Economics Association
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• v.46 no.3
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• pp.1-12
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• 2008

This study examines the unique characteristics of the color red in relation to images used in areas other than fashion, such as the film or advertising industries. Based on analysed results, the aim was to identify red-colored costume's images expressed in contemporary fashion. Analysis of collected data has lead to four main findings. First, the fashion in which the red color is used delivers a voluptuous image when combined with a skinny silhouette or glossy and transparent dress material, arousing a strong sexual desire in a direct or indirect manner when exposing the body in public. Second, the fashion emphasizes a simplified appearance by minimizing the steps of the production process such as cutting, sewing, and decoration without artificial structural lines and creates an image of simplicity through a single red color or tone-in-tone colorations. Third, the red color, which carries a simultaneous negative and pleasure image represents grotesque playfulness by distorting or exaggerating clothes, transforming the body in disregard of clothing construction, or introducing unnatural makeup. Fourth, in combination of simple and clinging shapes, a material feeling tough like leather and an intensely noticeable red tone, promotes the feminine rather than masculine quality in a splendid, aggressive sporty and active "alpha girl" image.

• Journal of the Korea Furniture Society
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• v.11 no.1
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• pp.45-51
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• 2000

It was thought that the stiffness of a coated specimen became lower than that of the solid wood because the stiffness of the dried film of coating material is lower than that of the solid wood. The authors were trying to compare the effect of lacquer varnish and rhus lacquer on the resonant frequency of the solid woods for the violin, spruce and maple. Vibration modal shape of coated specimens were same to those of solid woods, but the frequency became lower at each mode as were expected regardless of coat. frequency decrement of coated specimen was getting larger at upper mode in both European violin woods, however, rhus lacquer coated spruce specimens were less affected than lacquer varnish coated specimens.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.924-925
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• 2013

최근 미세가공 및 자동측정 분야가 고성능화 되어 자동화가 많이 실현되고 있다. 이러한 자동화는 고정밀도와 동시에 제품 생산에 대한 저비용, 단기납기, 고품질의 제품 창출로 이어진다. 현재 핸드폰 시장이 급성장함에 따라 핸드폰의 생산 주기가 현저하게 짧아지고 핸드폰 조립공정에 있어서 다양한 크기에 대한 핸드폰 평판표시장치인 LCD(Liquid Crystal Display)가 존재하고 있다. 핸드폰 조립공정에 있어서 이러한 다양한 LCD 표시장치(LCD, PDP, FED등)를 보호하기 위하여 보호매체인 PE/PET 필름을 부착하여 납품하도록 하고 있으며, 핸드폰 조립공정에서 발생할 수 있는 흠집 등 기타 불량을 줄이도록 노력하고 있다. 그러나 이러한 보호필름은 현재 핸드폰 조립공정 후판부에서 평판표시장치의 유리기판의 크기에 맞게 보호필름을 절단하도록 공정이 구성되어 있다. 본 논문에서는 이러한 핸드폰 조립공정을 개선하고 자동화하기 위하여 경박단소용 평판표시장치의 얇은 유리기판에 접착된 PE/PET 필름을 핸드폰의 다양한 패턴에 맞추어 하단의 유리기판에는 결함이 없도록 하여 보호필름만을 커팅 할 수 있는 커팅시스템을 제안하고 정밀계측에 대한 실험 데이터를 제시하고자 한다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.2
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• pp.72-77
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• 2016

Airplane reservoirs made of Al7075 are coated with an anodizing layer to maintain precision, air tightness and corrosion resistance. It is commonly required that the inner surface roughness of the reservoir be less than an average $0.2{\mu}m$ to maintain stable oil pressure. Even though precision polishing is necessary to achieve this quality it is not easy. Inner surface roughness is not uniform and the quality of the product is irregular because most of the work is done by hand. The purpose of this study is to design an exclusive polishing machine and to determine the standard cutting condition and polishing condition necessary for good inner surface roughness and to improve workefficiency.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.873-877
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• 2005

The burr of micro drilling and micro cutting on thin metal film is a major obstacle to mass production for micro PCB boards in micro technologies of personal computing and telecom explosion. As the burr affects on the assembling process, it is necessary to study continuously on control or elimination of the burr. In order to get higher valued products, it is also needed to competitive techniques with the high resolution. In this paper, we studied experimentally the burr generation that when it is processed on the copper foil by laser in micro-hole machining. Unlike mechanical machining the burr produced on substrate is a resultants of melt and re-solidification of a melten metal which was heated and treated by laser. And higher laser energy increases the size of burr. Therefor in micro-drilling with laser, it is difficult to reduce the effects of burr for very thin metal sheets. We investigated the stale of the burr and analyzed the laser ablation Cu micro machining with respect to laser intensity and processing time.

• Composites Research
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• v.22 no.6
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• pp.7-12
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• 2009

This paper deals with a fabrication method of composite hinge mechanisms for flapping-wing micro air vehicles. The fabrication process includes curing process of Graphite/Epoxyprepregs, laser cutting for high fabrication repeatability, laminating of Graphite/Epoxy prepregs with Kapton film which is used for flexure, and so on. The fabricated hinge mechanism was attached with PUMPS actuators and the measured flapping angle was $173^{\circ}$ when driving voltage was 300V 170Hz.

• Journal of Ceramic Processing Research
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• v.22 no.5
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• pp.590-596
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• 2021

The widespread use of TiC-based cermets as cutting tools, thin-film, ultracapacitors, nozzles, and bearings is primarily due to exhibit combination of excellent mechanical properties such as low density, high hardness, and stiffness. The TiC cermets were synthesized by high energy ball milling, which includes binder metal (Ni), carbides (WC and Mo2C), wherein the present study focus on the relationship between the core-rim structure, phase constitution, and mechanical properties. Here, using in situ TEM, we clearly observed the behavior of adjacent core-rim formation from the solid-phase reaction with grain refinement of the TiC phase control of both the milling time and lattice formation. Also, we proposed that mechanically alloyed core-rim structure can affect oxidation resistance of TiC-Mo2C-WC-Ni cermets strongly related to activation energy attributed to TiC particle size. The mechanical properties of TiC-Mo2C-WC-Ni cermets suggest the hardening effect is not considered only grain refinement, but rather is solid solution strengthening and particle-dispersion hardening. The present study paves the relation to the formation behavior of both TiC hard phase and core-rim structure due to the mechanical powder synthesis of novel TiC-based cermets.

• Horticultural Science & Technology
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• v.28 no.4
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• pp.580-584
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• 2010

The effect of planting densities on the growth of $Sedum$ $samentosum$ (4 collections) was investigated using nutrient film technique (NFT) with Yamazaki' lettuce nutrient solution (1982) from September 5th to October 24th in non-heating plastic film house. At 40 days, the plant height of 4 collections showed the range of 15.0-18.9 cm, and mean plant height was high the order of $10{\times}10$, $2.5{\times}2.5$, and $5{\times}5cm$. The growth of 'Pohang' and 'Wando' collections was better compared to that of 'Gunsan' and 'Wanju' collections. Number of node, stem diameter, and fresh and dry weight per plant were decreased in higher planting density. Despite the lower fresh weight per plant obtained, the fresh yield per $m^2$ was significantly increased in higher planting density. The mean fresh yield was $14.9kg{\cdot}m^{-2}$ in $2.5{\times}2.5cm$, and 'Pohang' collection showed the highest fresh yield ($17.6kg{\cdot}m^{-2}$). The first optimized harvesting time base on plant height was 30-40 days after NFT culture during autumn season. In eating quality, compression force of stem and bitterness of shoot were decreased in higher planting density. However, the heavy labor demanding high density cutting needs to be improved for hydroponic culture of $S.$ $samentosum$.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2011.10a
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• pp.39-41
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• 2011

The recycling rate of recovered paper in Korea is the highest in the world, 92%, but remanufacturing yield is low due to the extremely poor quality of the paper. The poor quality, in turn, influences to the reject amount in deinking process. To increase the yield of old newspaper recycling process, hydrophobic degree of inorganic pigments of deinking stock must be reduced. To determine the hydrophobicity, Pitch Potential Deposit Tester (PDT) was newly designed and applied with respect to the SB latex property of various quality used in Korea; its hydrophobic degree according to Tg, gel content, charge and particle size of latex and optimum designing condition of SB latex. And below are the conclusions: 1. The reason of excessive reject from old newspaper deinking process for total amount of printed ink is loss of inorganic pigments. When lipase, a biochemical catalyst, was applied with the purpose of preventing inorganic pigments loss about more than 70% of total reject weight and promoting hydration of pulp for deinking, deinking process yield of pre flotation secondary stage increased remarkably without any changes of deinking efficiency. 2. Lipase improved deinking stock by cutting ester linkage on surface of hydrophobic materials to promote its hydration. From this, it reached the conclusion that hydration degree of stock exercises significant effect on flotation deinking process yield. 3. Inorganic alkali promotes hydration of deinking stock. But there have been needs for more fundamental measures other than inorganic alkali of promoting hydration for yield improvement. For this, this study intended to find out reasons of chemical properties change on surface of hydrophobic material by change of pH. 4. Pitch Deposit Test (PDT) was performed for understanding principle of why surface of coating flake from OMG is hydrophobic and why it becomes hydrophilic when pH of stock is alkaline. As a result of this test, it is determined that swelling property by change of pH of latex film, which were used as coating adhesive is the reason for hydrophobic change. 5. Hydrophilicity of coating flake increased with hydrophilic pigments. And as more of SB Latex adhesive was used and higher of calcium hardness of stock became, its hydrophilicity decreased. SB Latex adhesive film is reformed by mechanical friction. For having hydrophilicity under neutral pH, strong bruising action such as kneading is required. 6. Because swelling of adhesive film decreases as Tg of SB latex gets lower and mean diameter gets smaller, it shows hydrophobicity under neutral pH. This lowers hydrophilicity of coating flake, which leads to easy elimination with flotation reject on DIP process. Therefore, for improving future flotation yield, it is necessary to develop to use eco-friendly clean SB latex by raising Tg and increasing mean diameter for recycling, and as a result, to reduce excessive loss of coating flake as a reject from deinking process.