• Journal of Adhesion and Interface
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• v.3 no.3
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• pp.22-29
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• 2002

UV curable coating system described here consists of double layers, namely under layer and top laser coatings. The former consists of organic-inorganic conductive materials and the latter consists of multifunctional acrylates. Transparent double layer coatings were prepared on the transparent substrates i.e. PMMA, PC, PET etc. by the wet and wet coating procedure. Their surface resistances and film properties were measured as a function of the top layer thickness and relative humidity. As the thickness of the top layer was less than $10{\mu}m$, the surface resistance in the range of $10^8{\sim}10^{10}{\Omega}/cm^2$ was obtained. The surface properties of the two-layer coating were remarkably improved compared with the single layer coating. The effects of migration of conducting materials on the film properties of multilayer coating were investigated by using contact angle and Fourier transform infrared/attenuated total reflection(FT-IR/ATR). It was found that the migration of dopant(dodecyl benzenesulfonic acid, DBSA) molecules were occurred from film-substrate interface to film-air interface in the organic conductive coating system but not in the inorganic one.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.06b
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• pp.97-101
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• 2006

In this paper, Multi-layer EM wave absorbers using Sendust are presented. The bandwidth of the Multi-layer Sendust EM wave absorbers over 10 dB is extended in S-Band And we investigated the mixing effects of $Al(OH)_3$ on Multi-layer Sendust EM wave Absorbers. As a result, the Multi-layer Sendust EM wave absorbers mixed with $Al(OH)_3$ showed a extended bandwidth over 10 dB compared with non-mixed Multi-layer Sendust EM wave absorbers in S-Band.

• Prospectives of Industrial Chemistry
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• v.22 no.3
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• pp.1-5
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• 2019

차세대 디스플레이 소자로서 상용화된 유기발광소자(OLED)는 현재 진공기반의 증착공정을 통해서 제작되므로 제조공정 비용이 높다. 진공 증착공정을 용액공정으로 교체하면 공정 비용을 크게 절감할 수 있지만, 용액공정으로 다층 박막 구조를 형성하기 어렵다는 문제점이 있다. 다층 구조를 제작할 때 이미 형성된 하부 박막 위에 새로 형성되는 박막이 하부 박막에 영향을 주기 때문이다. 이를 해결하기 위한 방법으로서 용액 공정용 잉크 용매의 내용제성을 증가시켜 상부 박막을 코팅할 때 하부 박막이 용해되거나 손상을 입지 않도록 하는 가교형 소재를 이용한 방법이 있다. 본 원고에서는 OLED 소자를 용액공정으로 제작하기 위한 가교형 정공 수송 재료의 특징과 개발 현황에 대해 소개하고자 한다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.177-177
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• 2016

우수한 내식성을 가지는 Zn 박막은 자동차, 가전제품, 전자제품 등에 사용되는 철 생산품의 수명 연장을 위하여 널리 사용되어 왔다. 최근 개발된 Zn-Mg 합금 박막은 Zn나 Mg에 비해 우수한 내식성을 나타내는 Zn-Mg 합금상을 형성하기 때문에 순수한 Zn 박막이나 다른 Zn 계 합금 박막에 비해 우수한 내식성을 가진다고 보고된 바 있다. 본 연구에서는 다양한 합금상의 형성을 위해 Mg 중간층 두께를 제어하며 Zn/Mg/Zn 다층 박막들을 합성하였으며 열처리를 통한 합금상의 변화, 그에 따른 박막의 내식성에 관해 연구하였다. Zn/Mg/Zn 다층 박막은 총 $4{\mu}m$의 두께로 Mg 중간층의 두께를 변화하였으며 비대칭 마그네트론 스퍼터링 공정을 이용하여 냉연강판 위에 합성하였다. 합성된 다층 박막은 다양한 Zn-Mg 합금상을 형성하기 위하여 진공로를 이용하여 $200^{\circ}C$에서 1시간 동안 어닐링 열처리를 실시하였다. 열처리 전, 후 Zn/Mg/Zn 다층 박막의 미세조직과 조성은 X선 회절 분석기 (XRD)와 전계방출형 주사전자현미경 (FE-SEM)과 글로우 방전 분광분석기 (GDEOES)를 사용하여 분석하였다. 어닐링 열처리를 통한 Zn-Mg 합금상 형성이 Zn/Mg/Zn 다층 박막의 내식성에 미치는 영향을 평가하기 위하여 동전위 분극시험과 EIS(Electrochemical impedance spectroscopy) 분석 실시하였다. FE-SEM과 GDOES 분석 결과, Zn/Mg/Zn 다층 박막들 각각의 중간층 Mg 두께는 1.5, 2.0, $2.5{\mu}m$ 였으며, 어닐링 열처리 후 중간층의 Mg이 상, 하부의 Zn 층으로 확산되면서 박막을 치밀한 구조로 변화시키는 것으로 확인되었다. XRD 분석 결과, 열처리를 하지 않은 Zn/Mg/Zn 다층 박막들에서는 Mg 상의 피크의 강도 차이만 존재할 뿐 Zn-Mg 합금상은 형성되지 않았다. 그러나 열처리를 후 Zn/Mg/Zn 다층 박막들에서 $MgZn_2$ 합금상이 형성되었으며, 중간층 Mg 두께가 $1.5{\mu}m$ 이하인 박막에서는 Zn 상이, 초과하는 박막에서는 Mg 상이 잔존하는 것을 확인하였다. EIS 분석 결과, 열처리 후 박막의 전하이동저항 값은 증가하며 박막의 어드미턴스 값이 감소하였으며 Bode phase plot을 통해 열처리 후 시정수(time constant)가 높은 주파수 영역에서 형성 되는 것을 확인하였다. 이는 열처리 후 Zn/Mg/Zn 다층 박막이 치밀해지고 내식성이 향상되었음을 나타낸다. 동전위 분극시험 결과에서도 마찬가지로 열처리 한 Zn/Mg/Zn 다층 박막들은 열처리 전 대비 내식성이 향상되는 것을 확인하였다. 열처리를 통한 Zn/Mg/Zn 다층 박막의 내식성의 향상은 우수한 내식성의 합금상의 형성과 박막 미세구조의 치밀화에 기인한다고 판단하였다. 또한 열처리 한 Zn/Mg/Zn 다층 박막들에서는 Zn와 $MgZn_2$ 상들이 공존 할 경우 가장 우수한 내식성을 나타내었으며, 이는 $MgZn_2$와 Zn 사이의 적은 전위 차이로 인해 갈바닉 부식 효과가 감소되었기 때문으로 판단된다.

• The Journal of the Acoustical Society of Korea
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• v.43 no.3
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• pp.261-269
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• 2024

In this paper, the acoustic performance of an absorptive silencer was enhanced by optimizing an arrangement of multi-layered absorbing materials. The acoustic performance of the silencer was evaluated through transmission loss, and finite element method-based numerical analysis program was employed to calculate the transmission loss. Polyurethane, a porous elastic material frequently used in absorptive silencers, was employed as the absorbing material. The Biot-Allard model was applied, assuming that air is filled inside the polyurethane. By setting the frequency range of interest up to the 2 kHz and the acoustic performance affecting properties of the absorbing materials were investigated when it was composed as a single layer. And the acoustic performance of the silencers with the single and multi-layered absorbing materials was compared with each other based on polyurethane material properties. Subsequently, the arrangement of the absorbing materials was optimized by applying the Nelder-Mead method. The results demonstrated that the average transmission loss improved compared to the single-layered absorptive silencer.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.4
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• pp.495-501
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• 2013

Purpose: This study was to develop golf range finder which could measure exact distance from golfer to flag by using telescope and biprism. Methods: Golf range finder was made that included telescope and biprism which could move in the telescope, and an accuracy of the range finder was analyzed in distance range 20~200 m. Results: An equation was made for measuring distance which was related at position of biprism, and we could measure distance successfully by using developed golf range finder. Biprism of 2 ${\Delta}$ was useful to measure in short distance but it had bad accuracy in long distance, and 0.5 ${\Delta}$ was more useful in long distance. Image got worse when the biprism approch to focal point of objective lens for measurement in long distance, so we developed multi-layer biprism to prevent the weak point. Conclusions: Image stabilization by biprism for measuring distance was confirmed. Even if hand was moving, the distance could be measured well by using biprism, and we could find that the induced equation for distance measurement was useful. We found that multi-layer biprism, which is was new developed, was more useful than general biprism when the biprism approched to focal point of objective lens for measurement in long distance.

• Journal of Korean Tunnelling and Underground Space Association
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• v.3 no.3
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• pp.3-13
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• 2001

The behavior of the masonry lining is studied to gain basic information on how to reinforce the masonry tunnels. Apart from the previous works on the masonry structures, the multi-course masonry structure, realistic in field condition, is considered and the constitutive relationship of the masonry is, therefore, established. The design charts of the orthotropic material properties are proposed according to the stiffness ratio and the crack initiation and subsequent propagation model is also considered to model the brittle nature of the masonry. A numerical analysis on the masonry panel is investigated to verify the proposed model and future works of the masonry lining are briefly explained.

• Polymer(Korea)
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• v.39 no.3
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• pp.514-521
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• 2015

In this study, we would like to describe peel strength and dynamic shear property on various substrates of multi-layered structural double-sided adhesive tape with or without adhesive (AD) prepared by UV curing for an automobile, construction, and display junction. According to adapt the adhesive, the peel and dynamic shear strength of adhesion tape prepared with acrylic foam or various plastic substrates increased with increasing molecular weight, however, decreased over 650000 molecular weight. The adhesion property shows high value at the thin AD layer with decreasing temperature. The interface property shows highest at MW 615000 (AD-4), and the interface junction below MW 615000 resulted to divide from acrylic foam and adhesive layer. From this study, the multi-layered structural double-sided adhesive tapes seem to be a useful for industrial area such as a low surface energy plastic material and curved substrate.

• Analyses & Alternatives
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• v.2 no.2
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• pp.67-91
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• 2018

This study scrutinizes the necessity and cases of the public and pension cooperation and tries to present the way of construction of information infrastructure for the pension systems suitable for Korea. The developed countries have recently been focusing on strengthening the multi-pillar pension system, while pension education and information services have emerged as an important element of the pension cooperation. The frame of the multi-pillar-pension system in Korea has already been constructed, but it is not substantial. Especially bad information on the pension system has seriously hindered the consolidation of the pension system. In order to solve this problem, we analyzed cases of public-private cooperation systems in Iceland, New Zealand, Netherlands, and Sweden. In order to build a basic infrastructure for construction pension cooperation in Korea, it is necessary to promote information exchange and cooperation among pension organizations and to improve the pension portal of NPS 'My Pension'. In addition, this study suggests establishing an association of private and public pension schemes, which manages the integrated information and education of pension systems.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.8
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• pp.1212-1219
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• 2009

In this paper, a state feedback gain controller using linear matrix inequality(LMI) for the multi-objective synthesis is designed, in the multi-layer structure with integral type servo system. The design objectives include $H_{\infty}$ performance, asymptotic disturbance rejection, time-domain constraints, on the closed-loop pole location. The results of computer simulation show the validity of the designed controller.