• Resources Recycling
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• v.22 no.3
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• pp.36-42
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• 2013

According to the recent community-based structures enlargement, specification, and diversification. It needs appropriate construction materials in terms of intensity and environmental aspects. Thus, in manufacturing the cement using micro limestone powder which is main material. It is also expected to save energies and reduces $CO_2$, by using the blast furnace slag and fly ash which are mitigated environmental load construction materials that emerged. In this research, The durability aspect tries to be grasped considering the chemical property according to the coherence of the hydration product. Consequently, The compressive strength was measured over 30 Mpa on 3rd. In addition, according to the content of the limestone powder, the setting time is promoted. It has the feature expanded in the length change. And it is determined because the possibility of replacing the existing for construction material such as it is measured compared with the time to use the portland cement usually that flexural strength is high with the age 7 days ago, so it is sufficient.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.166-166
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• 2007

ZnO는 육방정계(wurtzite) 결정구조를 지니며 상온에서 3.37eV의 wide band gap을 갖는다. ZnO의 엑시톤 결합 에너지는 GaN에 비해 2.5배 높은 60meV로서 고효율의 광소자 적용 가능성이 높다. 또한 고품위의 박막합성이 가능하다. 이러한 특성 때문에 display소자의 투명전극, 광전소자, 바리스터, 압전소자, 가스센서 등에 폭 넓게 응용되고 있다. ZnO박막의 제조는 스퍼터링, CVD, 진공증착법, 열분해법 등이 있다. 본 논문에서는 RF 마그네트론 스퍼터에 의해 제작된 ZnO 박막에 CMP공정을 수행하여 연마율과 비균일도 특성 및 광투과 특성을 연구하였다. ZnO박막은 $2{\times}2Cm$의 Corning glass위에 증착되었다. 로터리 펌프와 유확산 펌프를 이용하여 초기진공을 $2{\times}10^{-6}$ Torr까지 도달시킨 후 Ar과 $O_2$를 주입하였다. 증착은 상온에서 이루어졌으며 공정압력은 $6{\times}10^{-2}$Torr이였다. 초기의 불안정한 상태의 풀라즈마를 안정시키기 위해 셔터를 이용하여 pre-sputtering을 하였다. CMP 공정조건은 플레이튼 속도, 슬러리 유속, 압력은 칵각 60rpm, 90ml/min, $300g/cm^2$으로 일정하게 유지하였으며 헤드속도는 20rpm에서 100rpm까지 증가시키면서 연마특성을 조사하였다. 실리카슬러리의 적합성을 알아보기 위해 DIW와 병행하여 CMP공정을 수행하고 비교 분석하였다. CMP공정 결과 광투과도는 굉탄화된 표면의 확보로 인해 향상된 특성을 보였다. 실리카 슬러리를 사용하여 CMP를 할 경우는 헤드속도는 저속으로 하여야 양호한 연마특성을 얻을 수 있었다.

• KSBB Journal
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• v.21 no.2
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• pp.118-122
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• 2006

In this report, we describe that the use of GroEL/GroES-enriched S30 extract remarkably enhances the solubility and enzymatic activity of cell-free synthesized rPA, which requires the correct formation of 9 disulfide bonds for its biological activity. We found that the stable maintenance of redox potential is necessary, but not sufficient for the optimal expression of active rPA. In a control reaction without using additional molecular chaperones, most of the rPA molecules were aggregated almost instantly after their expression and thus failed to exhibit the enzymatic activity. However, by the use of GroEL/GroES-enriched extract, combined with IAM-treatment, approximately $30{\mu}g/ml$ of active rPA was expressed in the cell-free synthesis reaction. This result not only demonstrates the efficient production of complex proteins, but also shows the control and flexibility offered by the cell-free protein synthesis system.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.208-208
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• 2013

ZnO는 직접천이형 반도체로 약 3.37 eV의 넓은 에너지 band-gap과 60 meV의 비교적 큰 엑시톤 결합 에너지를 가지고 있다. 또한 단결정 성장 가능과 투명성 등 많은 장점들로 인하여 GaN와 대체할 자외선 또는 청색 발광소자나 ITO를 대체할 투명전극 같은 광범위한 광전소자로 큰 주목을 받으며 연구되어 왔다. 이러한 ZnO는 다양한 물질들의 첨가를 통해 인위적으로 특성변화가 가능한데 Mg, Be, Cd 첨가를 통한 에너지 밴드갭의 확장과 수축, Al 첨가를 통한 전기전도성의 증가 등이 그 예이다. 최근에는 밴드갭 조절을 이용한 ZnO-ZnMgO와 같은 이종접합구조가 광소자 등의 응용을 목적으로 많은 연구가 이루어지고 있다. 더불어 나노선이나 나노막대 같은 1차원 구조를 갖는 ZnO 계열 반도체의 연구는 현재 큰 이슈가 되고 있는 나노 크기의 소자 개발에 매우 큰 적용 가능성을 가지고 있다. 우리는 수열합성법을 이용하여 hexagonal ZnO 나노막대를 성장하고 그 표면에 core-shell 형태의 $ZnO-Zn_{1-x}Mg_xO$ (x=0.084) 양자우물을 원자층증착법으로 증착하였다. 본 연구에서는 만들어진 ZnO 나노막대와 ZnO-ZnMgO 나노막대, core-shell ZnO-ZnMgO 양자우물 sample들의 저온(5 K) Photoluminescence 측정을 통하여 광학적 band 구조를 분석하였다. 실험적으로 의도된 양자우물 두께와 다른 실제 형성된 양자무물의 두께를 알아내기 위하여 2차원 hexagonal 양자우물 band 구조에서 self-consistent nonlinear Poisson-Schr$\"{o}$dinger 방정식 계산과 컴퓨터 시뮬레이션을 이용하였으며, 이 방법으로 계산된 값과 실험값의 비교를 통하여 실제 형성된 양자우물의 두께를 정량적으로 유출할 수 있었다.

• Journal of the Korean Society for Nondestructive Testing
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• v.36 no.3
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• pp.188-194
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• 2016

We propose an acousto-optic technique for the nondestructive evaluation of adhesion properties of a Pt/Ti thin-film interface. Since there are some problems encountered when using prevailing techniques to nondestructively evaluate the interfacial properties of micro/nano-scale thin-films, we applied an interferometer that combined the acoustic and optical methods. This technique is based on the Michelson interferometer but the resultant surface of the thin film specimen makes interference instead of the mirror when the interface is excited from the acoustic transducer at the driving frequency. The thin film shows resonance-like behavior at a certain frequency range, resulting in a low-contrast fringe pattern. Therefore, we represented quantitatively the change in fringe pattern as a frequency spectrum and discovered the possibility that the interfacial adhesion properties of a thin film can be evaluated using the newly proposed technique.

• Journal of Broadcast Engineering
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• v.24 no.5
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• pp.802-812
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• 2019

With the rapid development in the field of unmanned aerial vehicles(UAVs) and drones, higher request to development of a surveillance system for a drone is putting forward. Since surveillance systems with fixed cameras have a limited range, a development of surveillance systems with a moving camera applicable to PTZ(Pan-Tilt-Zoom) cameras is required. Selecting the features for object plays a critical role in tracking, and the object has to be represented by their shapes or appearances. Considering these conditions, in this paper, an object tracking method with optical flow is introduced to track a tiny drone with a moving camera. In addition, a tracking method combined with kalman filter is proposed to track continuously even when tracking is failed. Experiments are tested on sequences which have a target from the minimal 12 pixels to the maximal 56337 pixels, the proposed method achieves average precision of 175% improvement. Also, experimental results show the proposed method tracks a target which has a size of 12pixels.

• Journal of the Korean Society for Railway
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• v.19 no.4
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• pp.436-444
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• 2016

The primary windings of the main transformer for rolling stock have several natural frequencies that can occur internal resonance with transient voltages induced on a high voltage feeding line. Factory testing is limited in its ability to determine whether or not transient voltage with various shape and duration can be excitable. This study presents the design of a high voltage windings model and simulation and analysis of the internal resonant characteristics in terms of the initial voltage distribution and voltage-frequency relationship using the electromagnetic transients program (EMTP). Turn-based lumped-parameters are calculated using the geometry data of the transformer. And, sub-models, being grouped into the total number of layers, are composed using a ladder-network model and implemented by the library function of EMTP. Case studies are used to show the layer-based voltage-frequency relationship characteristics according to the frequency sweep and the voltage escalation and distribution aspects in time-domain simulation.

• Journal of the Korea Society of Computer and Information
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• v.20 no.1
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• pp.49-62
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• 2015

In this study we have proposed the prototype of design support device for architectural design assessment using the building information modeling(BIM) data and the augmented reality(AR) technology. The proposed system consists of novel hardware composition with the transparent display, the mock-up model and the digital architectural model in the new shape of frame. The removal of background and the correction of viewer point in the capture video are proposed in order to use the transparent display in AR application. The BIM data formats are reviewed to be converted for using in AR application. Also the proposed system can be expanded to multi-user collaboration system from two user system through the suggested hardware and software compositions. The results of this study will be applied to use the mock-up model and digital architectural model in order to carry out the design assessment process efficiently and economically in the architectural design field.

• Journal of Digital Convergence
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• v.19 no.9
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• pp.59-65
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• 2021

This study intends to find a positive effect on the learning of elementary school students by developing the exhibition contents of on-offline museum. This on-offline museum contents were combined with existing exhibit types and direct experience elements, and the theory of [blended learning]. Through this study, analyzing the limitations of existing online museum and finding with experiment to see if the new contents had a learning effect compared to the existing online museum. As a result of the experimental study, the content with a [direct experience] was counted as a high satisfaction and frequency index, and the [play] and [experience] type of direct experience contents showed higher satisfaction than the indirect experience type contents. Through this study, we want to provide new implications and development possibilities in the development of contents that online museums can provide, and to promote various effects on children's education.

• Informatization Policy
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• v.28 no.3
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• pp.23-48
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• 2021

ICT technology development has led to a breakthrough change in government decision making by improving mutual communication between various stakeholders. The formation of ICT-based cooperation network between public organizations and civic tech developers to solve the problem of masks in the COVID-19 pandemic serves as a milestone. The purpose of this study is to examine the properties of e-Governance and analyze the dynamic network structure of the communication process for chat rooms created during the development of public mask apps. First, as a result of the analysis, the possibility of online-based e-Governance can be identified. In addition, the combination of expertise to solve social problems interacted organically within the network. Emotional communication for cooperation between key actors was marked as important for the successful operation of the network.