• 한국의상디자인학회지
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• 제4권1호
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• pp.173-183
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• 2002

The orchid has a very elegant color and various forms in the nature or the ground for human life and the mother of life, The purpose of this study is to express some creative formative art by using the orchid as motive, and thereby, suggest the possibility of an artistic modern costume design by reviewing the texture of the materials. The results of this study can be summarized as follows; First, it was confirmed through this study that the orchid with diverse forms and colors can be used as design motive in almost infinitely diverse ways, and that all the artificial forms or structures contain the elements of natural beauty. Second, the luxurious and rich sense of orchid‘s color can be maximized by using the complementary contrast effect of the dyeing technique and the color gradation effect through harmony among similar colors. Third, a high value-added costume can be created to meet modern men’s aesthetic desire by using such embroidery techniques as crochet, weaving, dyeing, beads embroidery and art flower. Fourth, different effects of texture can be rendered by using different materials of various textures and characteristics. In addition, the possibility of creative expression for costume as formative art can be enhanced by expanding the expressions of the materials.

• 한국학교수학회논문집
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• 제2권1호
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• pp.55-66
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• 1999

In mathematics education, teaching-learning activity can be divided largely into the understanding the mathematical concepts, derivation of principles and laws acquirement of the mathematical abilities. We utilize various media, teaching tools, audio-visual materials, manufacturing materials for understanding mathematical concepts. But sometimes we cannot define or explain correctly the concepts as well as the derivation of principles and laws by these materials. In order to solve the problem we can use the computer. In this paper, ′the process of the length of curve being equal to the sum of the vectors when intervals get smaller′ and ′the process of calculating volume of spinning curve by using definite integral.′ Using the computers is more visible than other educational instruments like blackboards, O.H.Ps., etc. Also it can help students with solving mathematical problems intuitively. Consequently more effective teaching-learning activity can be done. Usage of computers is the best method for improving the mathematical abilities because computers have functions of the immediate reaction, operation, reference and deduction. One of the important characters of mathematics is accuracy, so we use computers for improving mathematical abilities. This paper is about the program focused on the part of "the application of definite integral", which exists in mathematical curriculum the second and third grade of high school. When this study is used for students as assisting materials, it is expected the following educational effect. 1. Students will have precise concepts because they can understand what they learn intuitively. 2. Students will have positive thought by arousing interests of learning because this program is composed of pictures, animations with effectiveness of sound. 3. It is possible to change the teacher-centered instruction into the student-centered instruction. 4. Students will understand the relation between velocity and distance correctly because they can see the process of getting the length of curve by vector through the monitor. For the purpose of increasing the efficiencies and qualities of mathematics education, we have to seek the various learning-teaching methods. But considering that no computer can replace the teacher′s role, teachers have to use the CIA program carefully.

• 한국재료학회지
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• 제20권2호
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• pp.51-54
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• 2010

Transparent conductive films of single wall carbon nanotube (SWCNT) were prepared by spray coating method. The effect of acid treatment on the SWCNT films was investigated. The field emission scanning electron microscope (FESEM) shows that acid treatment can remove dispersing agent. The electrical and optical properties of acid-treated films were enhanced compared with those of as deposited SWCNT films. Nitric acid ($HNO_3$), sulfuric acid ($H_2SO_4$), nitric acid:sulfuric acid (3:1) were used for post treatment. Although all solutions reduced sheet resistance of CNT films, nitric acid can improve electrical characteristics efficiently. During acid treatment, transmittance was increased continuously with time. But the sheet resistance was decreased for the first 20 minutes and then increased again. Post-treated SWCNT films were transparent (85%) in the visible range with sheet resistance of about $162{\Omega}/sq$. In this paper we discuss simple fabrication, which is suitable for different types of large-scale substrates and simple processes to improve properties of SWCNT films.

• 한국재료학회지
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• 제30권4호
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• pp.204-210
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• 2020

ZnO thin films are of considerable interest because they can be customized by various coating technologies to have high electrical conductivity and high visible light transmittance. Therefore, ZnO thin films can be applied to various optoelectronic device applications such as transparent conducting thin films, solar cells and displays. In this study, ZnO rod and thin films are fabricated using aqueous chemical bath deposition (CBD), which is a low-cost method at low temperatures, and environmentally friendly. To investigate the structural, electrical and optical properties of ZnO for the presence of citrate ion, which can significantly affect crystal form of ZnO, various amounts of the citrate ion are added to the aqueous CBD ZnO reaction bath. As a result, ZnO crystals show a nanorod form without citrate, but a continuous thin film when citrate is above a certain concentration. In addition, as the citrate concentration increases, the electrical conductivity of the ZnO thin films increases, and is almost unchanged above a certain citrate concentration. Cu(In,Ga)Se₂ (CIGS) solar cell substrates are used to evaluate whether aqueous CBD ZnO thin films can be applicable to real devices. The performance of aqueous CBD ZnO thin films shows performance similar to that of a sputter-deposited ZnO:Al thin film as top transparent electrodes of CIGS solar cells.

• 한국안전학회지
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• 제6권2호
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• pp.5-13
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• 1991

In this paper, the interfacial stress intensity factors( $K_{i}$＝ $K_1$＋i $K_2$) for the edge interface crack in the dissimilar materials(isotropic-isotropic materials, isotropic-composite materials) were analysed by BEM(Boundary Element Method). The fatigue crack growth behaviour was investigated by load constant fatigue test. From the experimental results, the relationship between da/dN and interfacial stress intensity facto, ( $K_{i}$ or $K_1$) can be expressed by Paris'law for homogeneous materials.s.s.

• 한국지하수토양환경학회지:지하수토양환경
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• 제18권1호
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• pp.57-66
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• 2013

Although the quantity of dredged soils has increased owing to recent new harbor construction, sea course management, polluted sediment dredging, and four-river project, the reuse or recycling of those dredged soils has not done properly in Korea. To develop measures to utilize them in various ways for reuse or recycling, the biophysicochemical properties of dredged soils and sediment were assessed in this study. Samples were classified according to their sources-river and sea-by location, and as dredged soil and sediment depending on storage time. The results showed that dredged materials from the sea have high clay content and can be used for making bricks, tiles, and lightweight backfill materials, while dredged materials from the river have high sand content and can be used in sand aggregates. Separation procedures, depending on the intended application, should be carried out because all dredged materials are poorly sorted. All dredged soils and sediments have high salinity, and hence, salts should be removed before use for cultivation. Since dredged materials from the sea have adequate concentrations of nutrients, except phosphate, they can be used for creating and restoring coastal habitats without carrying out any additional removal processes. The high overall microbial activities in dredged materials from the river suggested that active degradation of organic matter, circulation of nutrients, and provision of nutrients may occur if these dredged materials are used for cultivation purpose.

• 대한토목학회논문집
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• 제31권6B호
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• pp.541-550
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• 2011

본 연구는 자갈접촉 산화공법의 단점을 연속접촉재 자유월류형 역사이폰 만곡수로시스템으로 보완함으로써 하천수질의 개선효과를 증대시키기 위한 것이다. 이 시스템은 접촉시간의 확장으로 시설규모를 축소시키고, 접촉재의 필터화를 통해 공극의 폐쇄 시 교체가 용이하도록 개선하였다. 또한 이 시스템은 단일 접촉재 사용으로부터 혼합 연속 접촉재를 사용할 수 있도록 개량된 수질개선 공법으로 개발되었다. 개발된 시스템은 대전광역시 소재 지방하천인 탄동천 일부구간에 설치하여 현장실험으로 수질개선효과를 확인하였다. 몇 차례의 현장실험을 통한 수질개선효과 검증결과는 하천수질의 생활환경기준 검사항목으로 SS, BOD, 총대장균수의 수질 개선효과는 55~83% 감소율을 보여 국내 하천수질 정화시설의 목표치인 60~75%를 상회하는 양호한 것으로 확인되었다.

• 한국실내디자인학회논문집
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• 제21권1호
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• pp.177-185
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• 2012

The purpose of this study is to use as the basic data for design method in commercial space. So, we analyzed whether any emotion was induced by finishing materials in the commercial space. And we was to suggest expression methods of finish materials to induce in the emotional space. The results of this study are as follows : First, we could know that the emotional design is needed to enhance satisfaction of consumers. The role of finishing material is very important in emotional expression in the commercial space. Second, we extracted the adjectives vocabulary(14 pairs) to evaluate the space emotion. we could educe the four kinds of space emotion by Factor Analysis. In addition, we could arrange the emotional words to represent each space type(Decoration : 5 pairs, Expand : 4 pairs, Limitation : 3 pairs, Hierarchy : 2 pairs). Third, to use finishing materials and wall is very effective to induce the emotion in the emotional space. To use the color is good among the elements of finishing materials. Fourth, We could find that the center of the types of emotional space was induced with the boundary and the decoration. If we use contrasting colors and accent colors in the commercial space, we can induce the center and the boundary together. And if we use colorful or unusual patterns, we can induce the center and the decoration together. Fifth, To induce the expand, we should finish with one color in space. And To induce the center, we should finish with one type of the color or pattern and then we should partially use the contrast color and special pattern. the case of boundary, it is good method to part emphasize by color, texture and materials. And we can induce the decoration with materials and patterns.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.237.1-237.1
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• 2016

Electrical properties of graphene-based field effect transistors (G-FETs) can be degraded in ambient conditions owing to physisorbed oxygen or water molecules on the graphene surface. Passivation technique is one of a fascinating strategy for fabrication of G-FETs, which allows to sustain electrical properties of graphene in the long term without disrupting its inherent properties: transparency, flexibility and thinness. Ironically, despite its importance in producing high performance graphene devices, this method has been much less studied compared to patterning or device fabrication processes. Here we report a novel surface passivation method by using atomically thin self-assembled alkane layers such as C18- NH2, C18-Br and C36 to prevent unintentional doping effects that can suppress the degradation of electrical properties. In each passivated device, we observe a shift in charge neutral point to near zero gate voltage and it maintains the device performance for 1 year. In addition, the fabricated PG-FETs on a plastic substrate with ion-gel gate dielectrics exhibit not only mechanical flexibility but also long-term stability in ambient conditions. Therefore, we believe that these highly transparent and ultra-thin passivation layers can become a promising candidate in a wide range of graphene based electronic applications.

• Journal of the Korean Wood Science and Technology
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• 제46권2호
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• pp.189-201
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• 2018

Intumescent system is a highly effective flame retardant technology that takes advantage of the mechanism of foaming and carbonization. In order to materialize Intumescent system, it is necessary to use reinforcement material to improve the strength of the material. In this study, we used kenaf as a natural fiber to manufacture intumescent/EVA (ethylene vinyl acetate) composites to improve mechanical and flame retardant performance. Finally two materials with different particle shape are applied to one system. Therefore, the influence factors of the particles with different shapes on the composite material were analyzed based on the tensile test. For this purpose, we have used the tensile strength analysis model and confirmed that it can only act as a partial strength reinforcement due to weak binding force between the matrix and particles. In the combustion characteristics analysis using cone calorimeter and UL 94, the combustion characteristics were enhanced as the content of Intuemscent was increased. As the content of kenaf increased, combustion characteristics were strengthened and carbonization characteristics were weakened. Through the application of kenaf, it can be confirmed that elastic modulus improvement and combustion characteristics can be strengthened, which confirmed the possibility of development of environmentally friendly flame retardant materials.