• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.386-387
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• 2006

This research describes a new constructing method of multifunctional biosensor using many kinds of biomaterials. A metal particle and an array was fabricated by photolithographic. Biomaterials were immobilized on the metal particle. The array and the particles were mixed in a buffer solution, and were arranged by magnetic force interaction and self-assembly. A quarter of total Ni dots were covered by the particles. The binding direction of the particles was controllable, and condition of particles was almost with Au surface on top. The particles were successfully arranged on the array. The biomaterial activities were detected by chemiluminescence and electrochemical methods.

• Advances in nano research
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• 제12권6호
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• pp.593-603
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• 2022

The critical buckling temperature rise of a newly proposed piezoelectrically active sandwich plate (ASP) has been investigated in this work. This structure includes a porous polymeric layer integrated between two piezoelectric nanocomposite layers. The piezoelectric material is made of a passive polymeric material that is activated by lead-free nanowires (NWs) of zinc oxide (ZnO) embedded inside the matrix. In both nanocomposite layers and porous core, functional graded (FG) patterns have been considered for the distributions of ZnO NWs and voids, respectively. By adopting a higher-order theory of plates, the governing equations of thermal buckling are obtained. This set of equations is then treated using an extended mesh-free solution. The effects of plate dimensions, porosity states, and the nanowire parameters have been investigated on the critical buckling temperature rises of the proposed lightweight ASPs with different boundary conditions. The results disclose that the use of porosities in the core and/or mixing ZnO NWs in the face sheets substantially arise the critical buckling temperatures of the newly proposed active sandwich plates.

• 공업화학
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• 제27권2호
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• pp.115-122
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• 2016

사람의 머리카락, 눈, 피부 등에서 발견되는 멜라닌은 자연의 생물체에 존재하는 어두운 색소를 가르치는 통칭이다. 멜라닌은 자유 라디컬을 흡수해서 제거하는 특성을 가지고 있어, 해로운 UV 광선이 생체로 침투할 때, 세포 및 조직을 보호하는 역할을 한다. 또한, 전기적 전도성 및 이온 전도성을 가지고 있으며, 항산화성, 젖은 상태에서의 접착성, 금속이온 킬레이팅 등 다기능성으로 인해, 다양한 분야에서의 응용이 주목받고 있다. 자연계에 존재하는 생체 멜라닌의 구조를 정확하게 정의할 수는 없지만, 멜라닌의 응용 분야는 센서, 의료기기 등으로 확대되고 있다. 본 미니총설에서는 멜라닌의 원천과 합성, 구조와 특성, 그리고 다양한 분야로의 응용 가능성에 대해서 구체적으로 논의한다.

• 한국재료학회지
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• 제22권5호
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• pp.227-236
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• 2012

Ionomer is a thermoplastic that is composed of covalent bonds and ionic bonds. It is possible to use this material in processes such as injection molding or extrusion molding due to the material's high oil resistance, weatherproof characteristics, and shock resistance. In this study, a new ionomer having a multifunctional group was prepared by a stepwise neutralization system with the addition of acidic and salt additives. In step I, to increase the contents of the multifunctional group and the acid degree in ethylene acrylic acid (EAA), MGA was added to the ionomer resin (EAA). A new ionomer was prepared via the traditional preparation method of the ionic cross-linking process. In step II, metal salt was added to the mixture of EAA and MGA. The extrusion process was performed using a twin extruder (L/D = 40, size : ${\varphi}30$). Ionomer film was prepared for evaluation of gas permeability by using the compression molding process. The degree of neutralized and ionic cross-linked new ionomer was confirmed by FT-IR and XRD analysis. In order to estimate the neutralization of the new ionomer film, various properties such as gas permeation and mechanical properties were measured. The physical strength and anti-scratch property of the new ionomer were improved with increase of the neutralization degree. The gas barrier property of the new ionomer was improved through the introduction of an ionic site. Also, the ionic degree of cross-linking and gas barrier property of the ionomer membrane prepared by stepwise neutralization were increased.

• Composites Research
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• 제29권6호
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• pp.395-400
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• 2016

최근에는 이온 전도도의 감소없이 높은 기계적 물성을 가진 구조 복합재를 개발하기 위하여 에폭시 매트릭스를 기반으로 하여 전해질을 함유한 다기능성 구조 전해질에 대한 연구가 활발히 진행 중이다. 구조 전해질의 최적 함량 및 소재 선정에 대해서는 많이 연구되고 있는 반면, 경화 거동에 따른 특성 분석에 관한 연구는 더디게 진행되고 있기 때문에 본 연구에서는 구조 성능과 에너지 저장 성능을 동시에 가진 고체 전해질을 함유한 에폭시 기반의 구조 전해질을 다양한 경화 시간 및 온도에 따라 제조하고 기계적 특성 및 이온 전도도 특성을 측정하였다. 그리하여 전해질의 열 분해가 일어나지 않는 온도 범위 내에서 에폭시가 충분히 경화할 수 있는 경화 조건을 통해 115 MPa와 $6{\times}10^{-5}S/cm$의 값을 동시에 가지는 구조 전해질을 얻었다.

• 소성∙가공
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• 제26권4호
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• pp.216-221
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• 2017

Recently, interest in multifunctional energetic structural materials (MESMs) has grown due to their multifunctional potential, especially in military applications. However, there are few studies about extrinsic factors that govern the reactivity of MESMs. In this paper, a shock compaction process was performed on the nano Ni/Al-mixed powder to investigate the effect of particle size on the shock reaction condition. Additionally, heating the statically compacted specimen was also performed to compare the mechanical properties and microstructure between reacted and unreacted material. The results show that the agglomerated structure of nanopowders interrupts the reaction by reducing the elemental boundary. X-ray diffraction analysis shows that the NiAl and $Ni_3Al$ intermetallics are formed on the reacted specimen. The microhardness results show that the $Ni_3Al$ phase has a higher hardness than NiAl, but the portion of $Ni_3Al$ in the reacted specimen is minor. In conclusion, using Ni/Al composites as a reactive material should focus on energetic use.

• 한국재료학회지
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• 제28권12호
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• pp.685-690
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• 2018

In this study, a multifunctional ophthalmic lens material with an electromagnetic shielding effect, high oxygen permeability, and high water content is tested, and its applicability is evaluated. Metal oxide nanoparticles are applied to the ophthalmic lens material for vision correction to shield harmful electromagnetic waves; the pyridine group is used to improve the antibacterial effect; and silicone substituted with urethane and acrylate is employed to increase the oxygen permeability and water content. In addition, multifunctional tinted ophthalmic lens materials are studied using lens materials with an excellent antibacterial effect (2,6-difluoropyridine, 2-fluoro-4-pyridinecarboxylic acid) and functional (UV protection, high wettability) lens materials (2,4-dihydroxy benzophenone, 2-hydroxy-4-(methacryloyloxy)benzophenone). To solve problems such as air bubbles generated during the polymerization process for the manufacturing and turbidity of the lens surface, polymerization conditions in which the defect rate is minimized are determined. The results show that the polymerization temperature and time are most appropriate when they are $110^{\circ}C$ and 40 minutes, respectively. The optimum injection amount of the polymerization solution is 350 ms. The turbid phenomenon that appears in lens processing is improved by 10 to 95 % according to the test time and conditions.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.126-126
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• 2012

In past decades, the themal inkjet (TIJ) printer has been widely used as one of the most well-known digital printing technology due to its low cost, and high printing quality. Since the printing speed of TIJ printers are much slower than that of laser printers, however, there has been intensive efforts to raise the printing speed of TIJ printers. One of the most plausible methods to raise the printing speed of TIJ printers is to adopt a page-wide array TIJ printhead. To accomplish this goal, the high efficiency inkjet heating resistor films should be developed to settle the high power consumption problem of a page-wide array TIJ printhead. In this study, we investigated noble metal based multicomponent thin film resistor films prepared by atomic layer deposition (ALD) for a high efficiency inkjet printhead. Design concept, preparation, material properties of noble metal based multicomponent thin films will be discussed in terms of mutlfunctionality.

• Smart Structures and Systems
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• 제16권3호
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• pp.435-457
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• 2015

The most widely known form of multifunctional aircraft structure is smart structures for structural health monitoring (SHM). The aim is to provide automated systems whose purposes are to identify and to characterize possible damage within structures by using a network of actuators and sensors. Unfortunately, environmental and operational variability render many of the proposed damage detection methods difficult to successfully be applied. In this paper, an original robust damage detection approach using output-only vibration data is proposed. It is based on independent component analysis and matrix perturbation analysis, where an analytical threshold is proposed to get rid of statistical assumptions usually performed in damage detection approach. The effectiveness of the proposed SHM method is demonstrated numerically using finite element simulations and experimentally through a conformal load-bearing antenna structure and composite plates instrumented with piezoelectric ceramic materials.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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• pp.472-475
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• 2005

The electrical performances of liquid crystal (LC) cells with chloromethylated polyimide (CMPI) alignment layers were investigated. The CMPI layer was previously reported as a multifunctional layer that does role of LC alignment and planarization layer as well as photo-alignment material with high photosensitivity and excellent thermal stability. The capacitance-voltage (C-V) characteristics of LC cells with CMPI alignment layers were measured. Mechanical rubbing of the CMPI layer did not generate much difference in residual DC when compared to commercial PI. However, the LC cell with photo-oxidation CMPI layer shows a high residual DC value and a corresponding low voltage holding ratio (VHR) due to the photo-induced ionic charges on the alignment layer.