• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.389-390
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• 2012

In this study, we fabricate a superhydrophobic surface made of hierarchical nanostructures that combine wax crystalline structure with moth-eye structure using vacuum cluster system and measure their hydrophobicity and durability. Since the lotus effect was found, much work has been done on studying self-cleaning surface for decades. The surface of lotus leaf consists of multi-level layers of micro scale papillose epidermal cells and epicuticular wax crystalloids [1]. This hierarchical structure has superhydrophobic property because the sufficiently rough surface allows air pockets to form easily below the liquid, the so-called Cassie state, so that the relatively small area of water/solid interface makes the energetic cost associated with corresponding water/air interfaces smaller than the energy gained [2]. Various nanostructures have been reported for fabricating the self-cleaning surface but in general, they have the problem of low durability. More than two nanostructures on a surface can be integrated together to increase hydrophobicity and durability of the surface as in the lotus leaf [3,5]. As one of the bio-inspired nanostructures, we introduce a hierarchical nanostructure fabricated with a high vacuum cluster system. A hierarchical nanostructure is a combination of moth-eye structure with an average pitch of 300 nm and height of 700 nm, and the wax crystalline structure with an average width and height of 200 nm. The moth-eye structure is fabricated with deep reactive ion etching (DRIE) process. $SiO_2$ layer is initially deposited on a glass substrate using PECVD in the cluster system. Then, Au seed layer is deposited for a few second using DC sputtering process to provide stochastic mask for etching the underlying $SiO_2$ layer with ICP-RIE so that moth-eye structure can be fabricated. Additionally, n-hexatriacontane paraffin wax ($C_{36}H_{74}$) is deposited on the moth-eye structure in a thermal evaporator and self-recrystallized at $40^{\circ}C$ for 4h [4]. All of steps are conducted utilizing vacuum cluster system to minimize the contamination. The water contact angles are measured by tensiometer. The morphology of the surface is characterized using SEM and AFM and the reflectance is measured by spectrophotometer.

• 한국추진공학회지
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• 제14권2호
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• pp.29-38
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• 2010

하이브리드 로켓을 위한 파라핀 왁스/LDPE 혼합 연료에 관한 실험적 연구를 수행하였다. 혼합 연료 의 성능 평가를 위해 혼합 연료의 다양한 연소 특성을 순수 파라핀, HTPB, HDPE, SP-1a 연료와 비교하였다. 순수 파라핀의 후퇴율은 HDPE에 비해 large-scale과 lab-scale 모터에서 각각 10.2, 9.8배 증가 하였다. Lab-scale 혼합 연료의 후퇴율은 HDPE에 비해 3.4배 증가하여 HTPB, HDPE 연료보다는 높은 후퇴율을 나타냈으나 순수 파라핀, SP-1a에 비해서는 낮은 후퇴율을 나타냈다. 혼합 연료의 특성속도와 비추력은 순수 파라핀, HTPB, HDPE 보다 높았고 SP-1a 연료와 대등하였다. 이로부터 혼합 연료가 효과적인 하이브리드 로켓 연료가 될 수 있음을 확인하였다.

• 한국응용곤충학회지
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• 제62권3호
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• pp.131-137
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• 2023

호박꽃과실파리(Z. scutellata)는 박과작물에 피해를 주는 중요한 해충이다. 현재 큐루어(Cuelure)는 국내에서 검역 대상 해충으로 규정된 오이과실파리, 타우과실파리, 및 퀸슬랜드과실파리와 더불어 호박꽃과실파리 수컷 성충의 예찰에 다양한 제형으로 활용되고 있다. 본 연구는 액체, 고체, 및 왁스제형의 큐루어에 대한 호박꽃과실파리 수컷 성충의 야외 유인효과를 검증하기 위한 것으로 2021년 4월부터 10월까지 제주 2개 지역과 경북 1개 조사에서 2주 간격으로 모니터링하였다. 호박꽃과실파리의 발생밀도가 높은 제주지역에서는 7월부터 8월에 액체와 왁스제형의 큐루어에 호박꽃과실파리가 더 많이 유인되어 통계적인 유의차가 있었으나, 호박꽃과실파리의 발생밀도가 낮은 경북지역에서는 제형별 유인력에 차이가 없었다. 야외조사 결과를 바탕으로 액체와 왁스제형의 큐루어가 호박꽃과실파리 수컷 성충 예찰에 권장되며, 이 두 제형의 큐루어에 유인되는 검역 대상 과실파리류의 국내 예찰에 효과적일 수 있다.

• 복식
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• 제56권3호
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• pp.42-56
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• 2006

The purpose of this study is to review the literatures and the wall paintings of the ancient tombs of Koguryo in an effort to try to understand the characteristics of the culture of dyeing in Koguryo. The research findings follow: 1. The colors that were in vogue in Koguryo are five cardinal colors (red, blue, white, black, and yellow) and compound colors, like purple and green. Those colors were used in some or all parts of the clothing and even on some parts of the body. 2. Some clothing of Koguryo as shown in the wall paintings were made with a single and solid color by dip dyeing method. But the majority of the clothing had a variety of patterns. Among the patterns, the geometrical dot pattern took the majority. 3. The dyeing techniques used in Koguryo were printing, yarn dyeing, embroidery, wax resist dyeing, drawing and painting. The development of yarn dyeing method, weaving with silk-threads dyed in various colors, enabled to produce Geum fabrics, which were used for the upper classes' clothing. 4. The esthetic features represented in the colors of Koguryo include the beauty of contrast coloring, preference for red, preference for geometrical patterns, and the harmony of yin and yang.

• 복식
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• 제44권
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• pp.131-141
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• 1999

The purpose of this study was to investigate the various expressions with materials in fashion illustration using CAD comparing with hand work. The design motive for this study is to be selected from Bell Epoque era which was the revolutionary period in fashion illustration. The results of this study were as follows: 1. By using CAD, water color was well expressed to repeat brushing for the clarity, darkness, and brightness. It was more effective to use CAD in layering or duplicating complex and intricate patterns because the base color gets to be concealed under the repeated oil pastel. Acryl, like oil pastel, was easily absorbed in canvas, so it is effective to repeat brushing for expressing pure color. It was inconvenient to use wax crayon for controlling the moderate opacity because wax crayon absorbed water color dye stuffs, so crayon line was concealed when repetitions were being done. 2. The advantage of using CAD was convenience for getting rid of troublesome process and inefficient works. Also, CAD had a good tool like oil pastel in the use of coloring work by using pure color. By using CAD, various expressions on materials and texture of surface can be achieved effectively. Also, it is very strong substitute for time-saving, convenience, economic aspects from providing simple instrument, and production in the state of various kinds of paper and canvas as a method of visualization. Therefore, fashion illustration using CAD provides effective way of producing works, and gives promising vision in the future.

• 한국분말재료학회지
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• 제24권3호
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• pp.223-228
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• 2017

Nanopowders provide better details for micro features and surface finish in powder injection molding processes. However, the small size of such powders induces processing challenges, such as low solid loading, high feedstock viscosity, difficulty in debinding, and distinctive sintering behavior. Therefore, the optimization of process conditions for nanopowder injection molding is essential, and it should be carefully performed. In this study, the powder injection molding process for Fe nanopowder has been optimized. The feedstock has been formulated using commercially available Fe nanopowder and a wax-based binder system. The optimal solid loading has been determined from the critical solid loading, measured by a torque rheometer. The homogeneously mixed feedstock is injected as a cylindrical green body, and solvent and thermal debinding conditions are determined by observing the weight change of the sample. The influence of the sintering temperature and holding time on the density has also been investigated. Thereafter, the Vickers hardness and grain size of the sintered samples have been measured to optimize the sintering conditions.

• 분석과학
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• 제29권5호
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• pp.219-224
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• 2016

A sensitive method to detect trace anions in hydrofluoric acid (HF) by solid-phase extraction (SPE) clean-up and ion chromatography (IC) was described. Fluoride in HF solution was eliminated with solid-phase extraction, and residual fluoride, acetate, chloride, bromide, nitrate, phosphate and sulfate were consecutively separated with IC. The SPE parameters (selection of adsorbent, sample volume and pH, elution solvent and its volume) were optimized and selected. The removal effect of fluoride in HF solution was the best on Oasis WAX column, and the optimum conditions (1.0 mL of 25 % HF solution and 50 mM ammonium acetate 5 mL as elution solvent) were established by the variation of parameters. Under the established condition, the method detection limits of chloride, bromide, nitrate, phosphate, and sulfate were 0.04~0.30 µg/L in 25 % HF solutions (w/w) and the relative standard deviation was less than 5 % at concentrations of 20.0 and 40.0 µg/L. The concentrations of anions in a 25 % HF had detectable levels of 4.2 to 47.5 µg/L. The method was sensitive, reproducible and simple enough to permit the reliable routine analysis of anions in HF solution used in the process of producing semiconductors.

• 해양환경안전학회지
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• 제8권2호
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• pp.79-86
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• 2002

A heating cargo is solidified by several reasons during carriage. This study is to analyse a cargo accident which 811,202 US barrels of Nile Blend crude oil reamined solid In the tanks after discharge. There are some possibilities that low temperature of Beading cargo below cloud point and wax appearance temperature at loading time, heating interruption during voyage or discharging, and prohibition of crude oil washing during discharging might influence the cargo solidified. But we concluded that the defect of heating system would most affect the heating cargo solidified locally, and which blocked drain hole of bottom transverse and web frame and they obstruct flow of heating cargo in the tanks.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2002년도 추계학술발표회
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• pp.59-70
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• 2002

A heating cargo is solidified by several reasons during carnage. This study is to analyse a cargo accident which 811, 202 US barrels of Nile Blend crude oil reamined solid in the tanks after discharge. There are some possibilities that low temperature of loading cargo below cloud point and wax appearance temperature at loading time, heating interruption during voyage or discharging, and prohibition of crude oil washing during discharging might influence the cargo solidified. But we concluded that the defect of heating system would most affect the heating cargo solidified locally, and which blocked drain hole of bottom transverse and web frame and they obstruct flow of heating cargo in the tanks.

• 보존과학연구
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• 통권31호
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• pp.9-16
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• 2010

The Annals of the Joseon Dynasty is one of the World Heritage which should be conserved well. However, some of wax treated volume of the Annals of the Joseon Dynasty have damaged seriously. Currently a variety of efforts to conserve and restore the injured volumes are continued and many studies about the aging mechanism of the wax treated volume have being progressed. The analysis of VOCs (Volatile Organic Compounds) emitted from paper cultural heritage is one of the methods to understand the degradation pathway of paper cultural heritage. The analysis of VOCs emitted from paper cultural heritage has been mainly conducted by SPME (Solid Phase Microextraction) method. SPME is potable and simple method but it is difficult to collect all VOCs emitted from a book such as the Annals of Joseon Dynasty. The dynamic chamber system has generally used to do analysis of VOCs emitted from the building materials, furniture and electric appliances. The chamber system is possible to do quantitative and qualitative analysis by a continuous $N_2$ gas flow and the proper chamber which is able to gather all VOCs emitted from the Annals of the Joseon Dynasty. In this study, the most material among detected VOCs was Naphthalene. Naphthalene has used to prevent organic cultural heritage from being damaged by various microbes for a long time. Apart from Naphthalene, main VOCs were Acetic acid, 2-Chloroethanol, 2-Bromoethanol, Furfural, 1-Methylnaphthalene, Azulene, and 2,4-Dioctylphenol. Of these VOCs, Furfural especially was known for a marker which represents a different emission rate according to the aging level.