• 한국기계가공학회지
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• 제16권3호
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• pp.119-124
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• 2017

Machining optimization using typical computer-aided manufacturing (CAM) software mainly depends on tool paths, and it is impossible to predict the behavior of material or cutting force. In this paper, cutting force analysis simulation is performed on the Unibody Case of a mobile phone with the aim of optimizing cutting-force-based machining using the Third Wave Systems' AdventEdge Production Module. Machining time after optimization was shortened by 42% for roughing compared to pre-optimization, and actual machining time was reduced by 36.8%. For finishing, machining time was reduced by 92%, and actual machining time was reduced around 90%. A surface roughness analysis found that the post-optimization surface roughness was $1.16{\mu}m$ Ra, compared to a pre-optimization value of $1.75{\mu}m$ Ra.

• 한국염색가공학회지
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• 제26권4호
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• pp.347-352
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• 2014

Film thickness dependent nanostructure evolution by a post annealing was investigated in poly (3-hexylthiophene):phenyl-C61-butyric acid methyl ester(P3HT:PCBM) films for organic solar cells which were fabricated by dichlorobenzene(DCB) solvent. In case of a 70nm thin film, the thermal annealing process affected to slight increment of the P3HT crystals in the surface region. On the other hand, large number of small sized P3HT crystals near the surface region was formed in the 200nm thick film. The solar cell devices showed the 3% power conversion efficiency(PCE) in 1:0.65 and 1:1 ratio(by weight) of P3HT and PCBM in 70nm and 200nm thickness conditions, respectively. Despite to the similar PCE, the short circuit current Jsc was different in 70nm and 200nm devices, which was related to the different nanostructure of P3HT:PCBM after thermal annealing.

• 한국항공우주학회지
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• 제30권7호
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• pp.123-129
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• 2002

본 논문은 실제 저궤도 위성에서 GPS를 이용하여 궤도를 추정하는 연구 결과를 담고 있다. 우리별 3호의 GPS 수신기가 실제 측정한 3차원 위치 및 속도 정보를 이용하였으며, 추정 알고리즘으로는 실시간 계산을 위한 확장 칼만필터와 후처리를 위한 스무더를 사용하였다. 스무더는 확장 칼만필터를 통과한 값을 이용하여 다시 역으로 추정하는 과정을 거치게 되므로 전체적으로 안정화된 추정값을 제공한다. 본 논문에서는 스무더를 적용한 추정값을 이용하여 우리별 3호의 케플러 궤도 요소를 계산하고, 분석하였다.

• 한국염색가공학회지
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• 제10권1호
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• pp.11-19
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• 1998

For the purpose of standardization and practicability of dyeing by natural dyes, the mordanting and dyeing properties of cochineal and carminic acid were studied. Appropriate extraction, dyeing and mordanting condition of cochineal were determined, and the effect of mordanting method on dye uptake and color fastness of dyed fabric was investigated. The maximum absorbance of cochineal solution was 495nm, carminic acid was 533nm and 577nm. The color of carminic acid solution was affected by pH 6~9. The optimum temperature to extract cochineal was $80-100^\circ{C}$ and dyeing solution for 1 hour. And effective dyeing time to silk was 60min. Effective mordanting temperature was $80^\circ{C}$, and its time was 30min. In case mordants concentration, the maximum absorbance of Sn solution was 3%, K, Cu and Cr were in 1%. K/S value of dyeing fabrics was recoginazed by mordant treatment, specially Fe, Sn, Al, Cu. In the case of cochineal light fastness was increased by mordant treatment, specially Fe treatment. Perspiration fastness was good in acidic solution than in alkaline solution and perspiration fastness of cochineal was poor. Fastness of abrasion and dry-cleaning were good and these fastness improvement were generally effective for post-mordanting treatment.

• 한국염색가공학회지
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• 제26권3호
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• pp.263-271
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• 2014

The purpose of this study is to investigate the dyeability of silk fabrics with Humulus japonicus (Hwansam) extract which is a kind of weeds that grows wild in the suburbs. In the research, the general extract method was conducted with the extract from fresh herb of root-removed Humulus japonicus while we investigated the optimal dyeing conditions and dyeability depending on the changes of the kind of mordants, methods and temperature. The functional properties such as antibacterial activities, deodorization and UV protection were also reviewed. The ideal output, as a result, was shown at 100% of dye concentration, $90^{\circ}C$ of dyeing temperature and 40 minutes of dyeing time while in terms of dye uptake depending on the kind of mordants and methods, it was found that among four mordants of $SnCl_2$, $AlK(SO_4)_2$, $CuSO_4$, and $FeSO_4$ post-mordanting with $FeSO_4$ showed the best result. Color fastness to washing, dry cleaning and rubbing was found strong at grade 4-5 and the grade to light was as good as 3 while to perspiration was good at 4-5 as well. In aspects of functional properties, it showed excellent results of 99% deodorization rate, 98% UV protection rate and 99.9% bacterial reduction against Staphylococcus aureus.

• 대한인간공학회지
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• 제28권3호
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• pp.27-31
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• 2009

To evaluate the usability of a Kimchi refrigerator, we performed an evaluation test that consisted of an experiment and a post-hoc questionnaire survey. In this study, we focused on the older women who have less physical and cognitive ability than younger women. In physical usability, there was no significant difference between the older and the younger subject group. However, there was some significant statistical difference in the results of cognitive usability test. When the subjects debriefed their operations after finishing the experiment, the all subjects in the older group reported the difficulties in identifying the labels and icons in the control panel and in understanding operation sequences. Also, they couldn't learn and remember the operation procedures well. Based on the analysis of the video protocols, some causes of the problems were found and then several improvement ideas were suggested.

• 한국염색가공학회지
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• 제24권4호
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• pp.270-280
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• 2012

This study examined the dyeing characteristics of five oriental herbs, namely Gardenia jasminoides, Sophora japonica L., Rheum coreanum, Rhus javanica L., Ginkgo biloba L., on fabrics with traditional fermentation using malt. And the properties of Hwangsu (mineral water) of Yeongcheon (Korea)as a mordant in the post-treatment of textile were evaluated. The dyeability and fastness of cotton fabric and silk to light and washing as well as different fermentation periods and temperatures were investigated, and the following results were obtained. The dyeability of the fermented and non-fermented material did not show a significant difference. Fabrics mordanted with Hwangsu generally exhibited a reddish color due to the presence of iron. The dyeing of cotton fabric and silk by fermentation and Hwangsu mordanting were found to be effective on Rhus javanica L. and Rheum coreanum. These results were confirmed through fastness to light 3 of cotton on Rheum coreanum and 3-4 of silk on Rhus javanica L., respectively. The washing fastness of both fabrics dyed with fermented Rhus javanica L. and Rheum coreanum was improved, showing higher K/S value after washing than before washing.

• 복식문화연구
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• 제29권1호
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• pp.65-86
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• 2021

This study aims to develop a hanbok design method in response to recent changes in consumption trends that emphasize new aesthetic and cultural values, which contrast with the existing cultural order and repetitive normative styles in fashion designing. With this in mind, our study explores the main features of deconstruction fashion design as a theoretical guide for developing a methodology for deconstruction hanbok design, on the basis of which new, experimental and creative hanbok design works can be produced. To do this, we first investigate current trends in hanbok design and changing concepts of Korean fashion design through literature review of previous studies. Secondly, we explore deconstructionism and analyze its features to lay down the foundation for a post-modern approach in hanbok design. As the result of analysis, the main features of deconstruction fashion design are summarized as the following: 1) non-finishing, 2) decomposing and recomposing, 3) recycling, 4) transparent, 5) grunge, 6) flattening, and 7) exaggeration. Based on the identified core features of deconstruction fashion design, we develop a creative method of hanbok design in the context of modern Korean fashion design. Finally, we show five design outputs via a 3D digital fashion design process using the CLO3D software program.

• 한국산학기술학회논문지
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• 제19권2호
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• pp.653-659
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• 2018

초고층 복합시설은 수많은 사람들이 이용하고 있는 도심의 핵심시설로서 안전성을 최우선으로 하고 있으며, 화재발생 시 연기와 유독가스는 대형사고를 유발할 수 있다. 본 연구는 초고층 복합시설물에서 화재에 의한 재난이 발생했을 경우, 피난자들이 신속히 안전한 곳으로 피할 수 있는 비상 대피통로용 접이장치에 적용되는 섬유 스크린 소재를 개발하는 데 목적이 있다. 섬유 스크린 소재 개발 방향은 일반적으로 사용되는 철제 소재와 달리 접이장치 내 롤형태로 장기간 보관 시 하중 부담이 적은 경량일 것과 차염/차연 기능이 우수해야 하며 복사열에 의한 피난자의 영향이 적어야 할 것이다. 이에 대해 난연성이 우수한 원단과 후가공을 조건으로 3종의 섬유 스크린 소재를 선정하여 열수축시험, 접촉열시험, 연소성시험, 난연도시험, 인장강도시험, 인열강도시험을 통해 성능평가를 수행하였다. 그 결과 경량의 원단이라도 후가공을 통해 우수한 성능을 발휘할 수 있으며, 실리콘수지 코팅이 섬유 스크린 소재 성능과 복사열에 의한 대피자의 안전을 확보할 수 있는 것으로 나타났다. 이에 따라 무게와 두께가 상이한 유리섬유 2종과 난연 실리콘수지 4종을 대상으로 코팅을 한 후 연소성시험을 수행하여 최적의 후가공조건을 평가하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제27권2호
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• pp.187-193
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• 2014

As a result of the cost of grains, the replacement of grains by co-products (i.e. DDGS) in feedlot diets is a common practice. This change produces diets that contain a lower amount of starch and greater amount of fibre. Hypothetically, combining feed grade urea (U) with slow release urea (Optigen) in this type of diet should elicit a better synchrony between starch (high-rate of digestion) and fibre (low-rate of digestion) promoting a better microbial protein synthesis and ruminal digestion with increasing the digestible energy of the diet. Four cannulated Holstein steers ($213{\pm}4$ kg) were used in a $4{\times}4$ Latin square design to examine the combination of Optigen and U in a finishing diet containing different starch:acid detergent fibre ratios (S:F) on the characteristics of digestive function. Three S:F ratios (3.0, 4.5, and 6.0) were tested using a combination of U (0.80%) and Optigen (1.0%). Additionally, a treatment of 4.5 S:F ratio with urea (0.80% in ration) as the sole source of non-protein nitrogen was used to compare the effect of urea combination at same S:F ratio. The S:F ratio of the diet was manipulated by replacing the corn grain by dried distillers grain with solubles and roughage. Urea combination did not affect ruminal pH. The S:F ratio did not affect ruminal pH at 0 and 2 h post-feeding but, at 4 and 6 h, the ruminal pH decreased as the S:F ratio increased (linear, p<0.05). Ruminal digestion of OM, starch and feed N were not affected by urea combination or S:F ratio. The urea combination did not affect ADF ruminal digestion. ADF ruminal digestion decreased linearly (p = 0.02) as the S:F ratio increased. Compared to the urea treatment (p<0.05) and within the urea combination treatment (quadratic, p<0.01), the flow of microbial nitrogen (MN) to the small intestine and ruminal microbial efficiency were greater for the urea combination at a S:F ratio of 4.5. Irrespective of the S:F ratio, the urea combination improved (2.8%, p = 0.02) postruminal N digestion. As S:F ratio increased, OM digestion increased, but ADF total tract digestion decreased. The combination of urea at 4.5 S:F improved (2%, p = 0.04) the digestible energy (DE) more than expected. Combining urea and Optigen resulted in positive effects on the MN flow and DE of the diet, but apparently these advantages are observed only when there is a certain proportion of starch:ADF in the diet.