• 한국염색가공학회지
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• 제33권4호
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• pp.191-201
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• 2021

In this study, an eco-friendly indigo reduction system(scale up reduction, use of buffer solution, and pH control) using baker's yeast(Saccharomyces cerevisiae) was applied for natural indigo(Polygonum tinctorium) dyeing of Hanji fabric and Hanji-mixture fabric(Hanji/Cotton, Hanji/Silk). The effect of concentration of baker's yeast, repeat dyeing, and bath reuse was investigated in terms of dye uptake indicating reduction power. And the oxidation-reduction potential(ORP) was monitored. We also evaluated color properties and colorfastness according to the color strength. The yeast concentration did not significantly affect the maximum reduction power. However, the highest yeast concentration was effective in improving the initial dye uptake, and its the reduction retention power was the most excellent. Even on the last reduction day, the effect of increasing the dye uptake by repeat dyeing was observed. And it was confirmed that the reduction bath could be reused for up to 30 days by supplementing yeast at the end of reduction. For all the fabrics used, deeper and darker PB color were obtained by repeat dyeing. As dyeing was repeated, purplish tint got stronger on the Hanji/Silk fabric compared to other fabrics. Regardless of the composition of Hanji fabrics and color strength, washing and dry cleaning fastness were relatively good with above rating 4-5, and fastness to rubbing and light were acceptable with a rating 3-4 ~ 4-5. The eco-friendly natural indigo dyeing process using niram and baker's yeast would offer global marketability and diversity of Hanji product as a sustainable high value-added material.

• 헤리티지:역사와 과학
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• 제57권1호
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• pp.110-123
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• 2024

온양행궁은 <온천행궁도(溫泉行宮圖)>『온궁사실(溫宮事實)』(1795), 『영괴대기(靈槐臺記)』 및 <영괴대도> 등의 문헌자료와 영괴대(靈槐臺), 신정비(神井碑)로 왕의 온행을 확인가능한 문화유산이다. 특히 1906년 헤르만 산더(Hermann Sander)가 촬영한 사진을 통해, 조선시대 온양행궁의 온천(탕실)이 일제강점기 초기까지 유지되고 있음을 확인할 수 있다. 본 연구는 온양행궁 관련 문헌 및 <온천행궁도>(1795)에 기초하여, 온양행궁 탕실의 건축형식을 밝혀내는 것을 목적으로 하고 있다. 이를 위해 첫째 온양행궁 및 탕실의 변천을 살펴보고, 둘째 왕의 목욕문화 및 행태를 고찰한 후, 셋째 <온천행궁도> 온천(탕실) 건축을 「온궁수리」를 통해 정리하고, 넷째 일제강점 초기 헤르만 산더(Sander)의 사진과 비교하여 조선 후기 마지막 온양행궁 온천(탕실) 건축 형식을 고찰하였다. 이상의 연구결과 다음과 같은 결론을 얻을 수 있다. 첫째, 온양행궁 온천(탕실)은 현종 초 온정실(溫井室, 8칸), <온천행궁도> 온천(탕실)로 이어지면서 조선 후기 『호서읍지』(1871)까지 유지되고 있는데, 일제강점기 초기 헤르만 산더(1906) 및 <1912년 충남 아산시 온양온천>(한국저작권 위원회) 사진 건축물과 일치하고 있다. 둘째, 조선시대 국왕의 목욕법은 목욕평상(沐浴平床) 또는 교의(交倚)에 앉아 세두, 유두, 목두 등을 시행하거나, 온천수 증기를 직접 쐬는 훈세, 탕정 앞에 목판을 깔고 앉아 물에 발을 담그는 침족 또는 침세, 그리고 배꼽 아래만 물에 담그는 반신욕인 체욕, 좌탕 등의 다양한 목욕방법을 채택하였다. 셋째, 온양행궁 온천(탕실)은 온천수가 상탕 서북쪽에서 분출되어 동쪽으로 꺾여 중탕으로 들어가고 남쪽으로 꺾어지면서 바깥으로 나와 하탕이 되는 구조로서, 탕체 주변부는 태안에서 실어 온 바둑돌을 탕실 바닥에 깔았다. 이상의 고찰로부터, 어실로부터 왕의 접근동선, 왕의 목욕법과 목욕도구, 입대하는 의관과 목욕보조 인력 등 목욕행태와 「온궁수리」에서 언급된 각 실 등의 구성을 헤르만 산더의 사진과 비교하여, 온양행궁 온천(탕실) 건축물을 추정할 수 있다.

• 전기화학회지
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• 제18권1호
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• pp.38-44
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• 2015

본 총설은 다공성의 메조포러스 이산화티타늄 박막을 기반으로 하는 양자점-감응 태양 전지의 최근 발전 과정에 대해 정리하였다. 나노스케일의 무기물 양자점이 가지는 본질적 특성에 기반하고 다양한 양자점 구성 물질을 이용하여, 용액-공정 기반의 다양한 3세대 박막 태양전지를 만들 수 있었다. 양자점 감응제는 준비하는 방법에 따라 크게 2가지로 나눌 수 있는데, 첫 번째는 콜로이드 형태로 용액상에서 준비한 다음 $TiO_2$ 표면에 붙이는 것이고 두 번째는 양자점 전구체가 녹아있는 화학조를 이용하여 직접 $TiO_2$ 표면에 성장시키는 것이다. 폴리썰파이드 전해질을 사용하여, 콜로이드 양자점 감응제의 경우는 최근 들어 정밀한 조성 조절을 통하여 전체 광전 변환효율이 ~7%에 이르렀고 화학조 침전법을 이용하여 준비된 대표적 감응제인 CdS/CdSe는 ~5%의 효율을 보이고 있다. 앞으로는 지금까지 보고된 양자점 감응제의 뛰어난 광전류 생성 능력을 유지하면서, 새로운 정공 전달체의 개발 및 계면 조절을 통한 개방 전압과 채움 상수의 개선을 통한 효율 증가 및 안정성에 관한 체계적 연구가 필요한 상황이다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.1639-1645
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• 1991

Because of the important role LD converters play in the production of high quality steel, various dynamic models have been attempted in the past by many researchers not only to understand the complex chemical reactions that take place in the converter process but also to assist the converter operation itself using computers. And yet no single dynamic model was found to be completely satisfactory because of the complexity involved with the process. The process indeed involves dynamic energy and mass balances at high temperatures accompanied by complex chemical reactions and transport phenomena in the molten state. In the present study, a mathematical model describing the dynamic behavior of LD converter process has been developed. The dynamic model describes the time behavior of the temperature and the concentrations of chemical species in the hot metal bath and slag. The analysis was greatly facilitated by dividing the entire process into three zones according to the physical boundaries and reaction mechanisms. These three zones were hot metal (zone 1), slag (zone 2) and emulsion (zone 3) zones. The removal rate of Si, C, Mn and P and the rate of Fe oxidation in the hot metal bath, and the change of composition in the slag were obtained as functions of time, operating conditions and kinetic parameters. The temperature behavior in the metal bath and the slag was also obtained by considering the heat transfer between the mixing and the slag zones and the heat generated from chemical reactions involving oxygen blowing. To identify the unknown parameters in the equations and simulate the dynamic model, Hooke and Jeeves parttern search and Runge-Kutta integration algorithm were used. By testing and fitting the model with the data obtained from the operation of POSCO #2 steelmaking plant, the dynamic model was able to predict the characteristics of the main components in the LD converter. It was possible to predict the optimum CO gas recovery by computer simulation

• 열처리공학회지
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• 제36권4호
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• pp.198-205
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• 2023

We investigated the effects of Al and Mg on the microstructure and hardness of the coating layer of galvanized steel sheets, by thermodynamic calculations, X-ray diffraction, scanning electron microscopy, and Vickers hardness tests of Zn-0.2Al, Zn-6Al-2Mg, and Zn-10Al-5Mg coating layers. Regardless of the alloy composition of the galvanizing bath, a Fe-Al layer was observed between the coating layer and steel sheet. The Zn-0.2Al coating layer consists of major h.c.p. Zn phase and minor f.c.c. Al phase. The fraction of f.c.c. Al phase (containing a significant amount of Zn) of the coating layer increases with increasing the chemical composition of Al of the galvanizing bath. The h.c.p. MgZn₂ phase was formed in the Al/Mg-containing Zn-6Al-2Mg and Zn-10Al-5Mg coating layers, forming Zn-Al-MgZn₂ eutectic microstructure. The primary MgZn₂ phase was additionally formed in the Zn-10Al-5Mg coating layers containing high concentrations of Al and Mg. The Vickers hardness values of Zn-0.2Al, Zn-6Al-2Mg, and Zn-10Al-5Mg coating layers were 59.1 ± 1.2 HV, 161.2 ± 5.7 HV, and 215.5 ± 40.3 HV, respectively. The addition of Al and Mg increased the hardness of the coating layer by increasing the fraction of the Al phase (containing Zn) and MgZn₂ intermetallic compound, which were harder than the Zn phase.

• 한국재료학회지
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• 제19권11호
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• pp.596-600
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• 2009

Electrochemical deposition characteristics of CdSe nanorods were investigated for hybrid solar cell applications. CdSe nanorods were fabricated by electrochemical method in $CdSO_4$ and $H_2SeO_3$ dissolved aqueous solution using an anodic aluminum oxide (AAO) template. Uniformity of CdSe nanorods was dependent on the diameter and the height of holes in AAO. The current density, current mode, bath composition and temperature were controlled to obtain a 1:1 atomic composition of CdSe. CdSe nanorods deposited by direct-current method showed better uniformity compared to those deposited by purse-current and/or purse-reverse current methods due to the bottom-up filling characteristics. $H_2SeO_3$ concentration showed more significant effects on pH of solution and stoichiometry of deposits compared to that of $CdSO_4$. A 1:1 stoichiometry of uniform CdSe nanorods was obtained from 0.25M $CdSO_4-5$ mM $H_2SeO_3$ electrolytes with a direct current of 10 $mA/cm^2$ at room temperature. X-ray diffraction and electron diffraction pattern investigations demonstrate that CdSe nanorods are a uniform cubic CdSe crystal.

• 한국실내디자인학회논문집
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• 제16권6호
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• pp.116-124
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• 2007

The purpose of this study is to find out the spatial characteristics of the multi-housing units in Seoul and Kyung-gi area since 2006. Literature review and content analysis were used for this study and 82units of the big size over $165m^2$ were analyzed to review such design characteristics as spatial composition, layout and linkage. Through this study, the following conclusions have been reached; 1) Most unit plans had 4LDK and 3bath types including family room as a public space. This results shows that family-room and bathroom has recently become more important than number of rooms in multi-housing units planning. 2) Diversity of plan figures such as mass-mixing, mass-separation and polygons(L, V-type)was showed in most unit plan, breaking from the standardized forms of box types. 3) Intermediated spaces such as foyers and halls in entrance zone were planned and sub-entrance into kitchen were planned for the various types of circulation and work-efficiency. Cases had private space separated from public space, the dispersion of rooms with the increase of connection by corridors, L-DK meaning the living room isolated from the dining and kitchen, partially located living room for a view in area distribution. The spatial planning of master-zone mostly consists of the types of two-rooms and an entry into a foyer(library, dress-powder room, bathroom and master bedroom). This study has a significant meaning on grasping current trend in Korean multi-housing and to provide information for future direction on housing-unit design.

• Fibers and Polymers
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• 제3권1호
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• pp.38-42
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• 2002

Polypropylene filaments were spun from a mixture of PP chips of two different Melt Flow Index (MFI) (3 MFI and 35 MFI). A significant difference was observed in the melting characteristics of the resultant filaments from either of the individual components as observed from the DSC. The main difference being in the degree of melting achieved at any temperature in the initial stages of the melting range, which was found to be higher in case of the filaments spun from the b]end. These filaments were then thermally bonded using silicon oil bath and heated roller method. Subsequently the bond strength of the filaments was measured on the Instron Tensile Tester using the loop technique. The values of the world strengths obtained from the blend were compared with those made from the individual component. It was found that the bond strength of the bonds obtained from the blended filament at a given temperature was higher than that of the bonds made from the filaments of either of the individual components, which is also suggested by the DSC curves. The difference in the bond strength was found to be as high as 25% in case of the blend with 60:40 composition ratios of the 3 MFI and 35 MFI components respectively.

• Journal of Electrical Engineering and Technology
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• 제10권4호
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• pp.1746-1751
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• 2015

In this study low voltage Plasma Electrolytic Oxidation (PEO) was utilized to eliminate high voltage PEO drawbacks such as high cost, dimensional deformation and porosity. Low voltage PEO produces a thin coating which causes low corrosion resistance. In order to solve such problem, 0.1~0.6M pyrophosphates were added in a bath containing 1.4M NaOH, and 0.35M Na₂SiO₃. 70 V PEO was conducted at 25℃ for 3 minutes. Chemical composition, morphology and corrosion resistance of the anodized coating were analyzed. The anodized film was composed of MgO, Mg₂SiO₄, and Mg₂O₇P₂. The morphology of film showed appropriately dense structure and low porosity in the anodized layers. It is found that low voltage Plasma Electrolytic Oxidation in cooperation with phosphating treatment can provide a good corrosion protection for the AZ31B magnesium alloy.

• 자원리싸이클링
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• 제12권4호
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• pp.30-37
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• 2003

황산 용액에서 Zinc-ferrite의 용해에 대한 반응속도론을 황산 용액의 반응온도와 농도 변화에 대해 조사하였다. 반응율(R)과 겉보기 반응 속도상수(K)는 황산 용액의 온도와 농도가 클수록 증가한다. Zinc-ferrite의 반응속도는 반응초기에서 $1-(1-K)^{1/3}=Kt$와 같은 속도식을 적용할 수 있다. 용해에 대한 활성화 에너지는 황산 용액의 농도에 관계없이 약 16.3kcal/mole 이다. Zinc-ferrite가 황산 용액에서 용해할 때는 Zinc-ferrite의 화학 양론적 조성으로 용해되며, Fe 또는 Zn의 단독으로는 용해되지 않는다.