• 한국지하수토양환경학회지:지하수토양환경
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• 제20권2호
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• pp.10-21
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• 2015

The present study introduces a novel numerical approach for solving dispersion dominated problems with Cauchy boundary condition in an Eulerian-Lagrangian scheme. The study reveals the incapability of traditional Neuman approach to address the dispersion dominated problems with Cauchy boundary condition, even though it can produce reliable solution in the advection dominated regime. Also, the proposed numerical approach is applied to a real field problem of radioactive contaminant migration from radioactive waste repository which is a major current waste management issue. The performance of the proposed numerical approach is evaluated by comparing the results with numerical solutions of traditional FDM (Finite Difference Method), Neuman approach, and the analytical solution. The results show that the proposed numerical approach yields better and reliable solution for dispersion dominated regime, specifically for Peclet Numbers of less than 0.1. The proposed numerical approach is validated by applying to a real field problem of radioactive contaminant migration from radioactive waste repository of varying Peclet Number from 0.003 to 34.5. The numerical results of Neuman approach overestimates the concentration value with an order of 100 than the proposed approach during the assessment of radioactive contaminant transport from nuclear waste repository. The overestimation of concentration value could be due to the assumption that dispersion is negligible. Also our application problem confirms the existence of real field situation with advection dominated condition and dispersion dominated condition simultaneously as well as the significance or advantage of the proposed approach in the real field problem.

• 한국의상디자인학회지
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• 제21권3호
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• pp.161-172
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• 2019

This study examines the characteristics and recent changes of the Hanbok industrial cluster in Gwangju Metropolitan City, in order to understand the problems in the activation of the Hanbok industry and to seek future policies. A total 32 companies comprise the 'Small Manufacturer Specialized Support Center of Hanbok' and were surveyed with a 41 questions with questions in four categories. The Gwangju Hanbok area has been in existence for more than 40 years and was composed of small groups of one or two manufacturers. They are experiencing the same difficulties as other Hanbok clusters, such as the aging of workers, the downturn of dress culture, and changing consumption paradigms. However, since 2015, various efforts have been made in order to seek countermeasures to cope with such difficulties, particularly with the foundation of the 'Small Manufacturer Specialized Support Center of Hanbok' with the support of the Ministry of Small Venture Business. This study focuses on the alterations in the current Hanbok industry due to the IT industrialization as well as the changes in the locations of the Hanbok clusters due to the revitalization of old towns by local governments., The results providing an opportunity to appreciate the problems therein and seek the solutions. Small manufacturers of the Hanbok cluster are trying to improve their entrepreneurship, digital technology application, and knowledge in accordance with the socio-economic trends, but they have limitations to practically apply it to business, barely keeping the minimum production base. The central government and the Gwangju should reinforce and expand the support for marketing and public relations for the Hanbok to foster the designer population, to establish mutual brands, to raise brand awareness, and to promote the technological perfection of the individual businesses, to allow them to cope with the current market trends, in order for the technological development and firm settlement of the local Hanbok industrial cluster.

• 천문학회보
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• 제44권2호
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• pp.48.4-48.4
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• 2019

We studied the metal-distribution of isolated Milky-way mass galaxy using various hydrodynamic solvers and investigated the difference of the result between AMR and SPH codes. In particle-based codes, physical quantities like mass or metallicity defined in each particle are conserved unless being injected explicitly by the effect of the supernova, whereas in the Eulerian codes the diffusion is simply accomplished by hydro-equation. Therefore, without including explicit physics of diffusion on the SPH- codes, the metal mixing in the galaxy or CGM only can be accomplished by the direct motion of the particles, however, the standard-SPH codes depress the instability of the turbulent fluid mixing. In this work, we simulated under common initial conditions, common gas-physics like cooling-heating models, and star-formation feedback using ENZO(AMR) GIZMO and GADGET-2 codes. We additionally included a metal-diffusion algorithm on the SPH-codes, which follows the subgrid-turbulent mixing model investigated by Shen et al. (2010) and compared the effect of the metal-outflow on the halo region of the galaxy in different hydro-solvers. We also found that for the implementation of the diffusion scheme in the SPH-codes, the existence of a sufficient number of the gas-particles, which is the carrier of the metals, is necessary. So we tested a new initial condition for proper implementation of the diffusion scheme on the SPH simulations. By comparing the metal-contamination of the circumgalactic medium with different hydrodynamics models, we quantify the diffusion strength of AMR codes using diffusion parameterization of the SPH codes and also suggest the calibration solutions in the different behavior of codes in metal-outflow.

• 한국재료학회지
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• 제20권6호
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• pp.301-306
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• 2010

The chemical formula of magnetite ($Fe_3O_4$) is $FeO{\cdot}Fe_2O_3$, t magnetite being composed of divalent ferrous ion and trivalent ferric ion. In this study, the influence of the coexistence of ferrous and ferric ion on the formation of iron oxide was investigated. The effect of the co-precipitation parameters (equivalent ratio and reaction temperature) on the formation of iron oxide was investigated using ferric sulfate, ferrous sulfate and ammonia. The equivalent ratio was varied from 0.1 to 3.0 and the reaction temperature was varied from 25 to 75. The concentration of the three starting solutions was 0.01mole. Jarosite was formed when equivalent ratios were 0.1-0.25 and jarosite, goethite, magnetite were formed when equivalent ratios were 0.25-0.6. Single-phase magnetite was formed when the equivalent ratio was above 0.65. The crystallite size and median particle size of the magnetite decreased when the equivalent ratio was increased from 0.65 to 3.0. However, the crystallite size and median particle size of the magnetite increased when the reaction temperature was increased from $25^{\circ}C$ to $75^{\circ}C$. When ferric and ferrous sulfates were used together, the synthetic conditions to get single phase magnetite became simpler than when ferrous sulfate was used alone because of the co-existence of $Fe^{2+}$ and $Fe^{3+}$ in the solution.

• 대한화학회지
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• 제37권1호
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• pp.83-91
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• 1993

염기성 용액에서 가벼운 란탄족 원소 착물의 전기화학적 거동을 직류(DC), 펄스차이 폴라로그래피(DPP), 순환전압전류법(CV) 및 정전위 전기분해법으로 조사하였다. 란탄이온들은 NaCl 지지전해질에서 o-cresolphthalexon(OCP)과 1:1로 배위하였으며, 전극반응은 2단계 1전자 환원반응이었다. 착물의 반파전위는 pH에 따라 변화하였으며 환원전류는 흡착성을 나타냈다. DC 및 CV에서 첫번째 1전자 환원반응은 유사가역적 거동을 나타냈으며, 환원 뒤에 형성된 음이온 라디칼은 이합체와 반응을 하였다. 두번째 환원파는 전자전이 반응에 이어 생성된 카르보 음이온의 빠른 양성자 첨가반응으로 비가역적 거동을 나타냈다. -1.80V에서 정전위 전해시간이 증가함에 따라 착물의 질은 청색은 점점 옅어져서 무색이 되었으며, 최종생성물은 전기적으로 비활성이었다. 따라서 Ln-OCP 착물의 단계적인 전극반응은 ECEC 메카니즘으로 제안되었다.

• Journal of the Korean Wood Science and Technology
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• 제30권1호
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• pp.40-47
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• 2002

PEG처리에 의한 국내산 주요 소경재 다섯 수종(소나무, 잣나무, 일본잎갈나무, 신갈나무, 굴참나무)의 치수안정성을 조사하고, 목재내의 PEG분포를 X선회절법에 의해 검토하였다. 그 결과 공시수종 모두 PEG 30%의 수용액에서 좋은 치수안정 효과를 보여 주었다. 또한 PEG농도 증가에 따라 PEG처리 목재의 중량증가율과 벌킹효과가 증가하였는데 침엽수재가 활엽수재에 비해 그 정도가 크게 나타났다. X선회절 결과, 잣나무는 만재와 조재 모두 2𝜃 = 19°와 2𝜃 = 23° 부근에서 PEG결정유래의 피크가 나타나지 않았다. 이러한 X선회절 결과는 잣나무재내에 신갈나무재보다 더 많은 양의 PEG가 존재하는 것을 의미하는 것으로서 치수안정성이 큰 이유를 설명해 주는 증거의 하나로 생각되었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.88-88
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• 2009

$BiFeO_3$(BFO), when forming a solid solution with $BaTiO_3$(BTO), shows structural transformations over the entire compositional range, which not only gives a way to increase structural stability and electrical resistivity but also applies a means to have better ferromagnetic ordering. In this respect, we have prepared and studied 0.7BFO-0.3BTO thin films on $Pt(111)/TiO_2/SiO_2/Si$ substrates by pulsed laser deposition. Various deposition parameters, such as deposition temperature and oxygen pressure, have been optimized to get better quality films. Based on the X-ray diffraction results, thin films were successfully deposited at the temperature of $600^{\circ}C$ and an oxygen partial pressure of 10mTorr. The dielectric, ferroelectric, and magnetic properties have then been characterized. It was found that the films deposited under lower oxygen pressure corresponded to lower leakage current. Magnetism measurement showed an induced ferromagnetism. The microstructures associated with. the magnetic and dielectric properties of this mixed-perovskite solid solutions were observed by transmission electron. microscopy, which revealed the existence of complicated ferroelectric domains, suggested that the weak spontaneous magnetization was closely associated with the decrease in the extent of rhombohedral distortion by a partial substitution of $BaTiO_3$ for $BiFeO_3$.

• 한국융합학회논문지
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• 제8권8호
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• pp.59-69
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• 2017

인문 사회과학 연구원들과 데이터베이스 전문가들이 태평양문제연구회(IPR)가 작성한 IPR 자료를 데이터베이스로 구축하기 위해 함께 하였다. 본 논문은 그 데이터베이스의 구축에서 IPR 자료의 품질을 보장하기 위한 쟁점과 해결책을 제시한다. 우리는 데이터베이스의 접근성을 위해 웹에 데이터베이스를 유지하여 연구원들이 웹 브라우저로 접근할 수 있도록 하며, 데이터베이스 구축의 편리성을 위해 통합 인터페이스를 제공하여 연구원들이 그 속에서 모든 작업을 수행하게 하며, 구축한 IPR 자료의 완전성을 위해 입력된 각 IPR 자료의 책임 소재를 밝히는 책임 입력과 책임 승인을 지원하며, 승인의 즉시성을 위해 연구원들의 입력을 원활히 하는 대화형 승인 과정을 지원한다. 또한 구축한 IPR 자료의 정확성을 보장하기 위해 우리는 데이터베이스 설계, 질의 처리, 트랜잭션 관리, 검색과 정렬 기법들을 사용한다. 특히, 레코드들 간의 존재 종속관계를 이용한 동시성 제어를 통하여 운영체제 파일과 그 파일의 경로 간의 정확성을 보장한다. 향후 연구로 내용 검색, 데이터베이스의 다운로드와 업로드, IPR 자료의 저작권 관련 작업을 포함한다.

• 인지과학
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• 제2권1호
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• pp.1-12
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• 1990

심리적 표상은 표상의 주체라고 할 마음의 존재문제와 표상되는 세계의존재 문제 를 제기한다. '명제태도' 라는 언어적 표상은 그것의 주어가 지칭하는는 마음의 존재를 문제 삼게할뿐 아니라 그러한 명제적 표상의 대상세계라고 할 명재적 사실의 존재문제 도 생기게 한다. 심리적 표상을 심리적 사건으로 간주할 때 그 사건의 뒤상이 문제된다. 어떤 다른 사건과 인과관계를 갖는지가 문제된다. 특히 신경과학적 사건과의 관게를 규명하는 문제가 중요하다. 심리적 표상은 이론적 대상의 세계고 간주될 수 있다. 그것은 신경과학의 발달 과정을 통하여 점차 해명될 수 있는 이론적 대상세계이다. 따라서 그것의 실재성도 과학의 발전에 의존하여 그 의미를 구체화할 수 있을 것이다. 철학이 제기하는 이러한 존재론적 문제들은 인지과학의 발전과 더불어 점차적으로 제조명될 성질의 것이다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.313-313
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• 2010

$BiFeO_3$ (BFO), when forming a solid solution with $BaTiO_3$ (BTO), shows structural transformations over the entire compositional range, which not only gives a way to increase structural stability and electrical resistivity but also applies a means to have better ferromagnetic ordering. In this respect, we have prepared and studied 0.8 BFO-0.2 BTO thin films on Pt(111)/$TiO_2/SiO_2$/Si substrates by pulsed laser deposition. Various deposition parameters, such as deposition temperature and oxygen pressure, have been optimized to get better quality films. Based on the X-ray diffraction results, thin films were successfully deposited at the temperature of $700^{\circ}C$ and an oxygen partial pressure of 10mTorr and 330mTorr. The dielectric, ferroelectric, and magnetic properties have then been characterized. It was found that the films deposited under lower and higher oxygen pressure corresponded to lower leakage current. Magnetism measurement showed an induced ferromagnetism. The microstructures associated with the magnetic and dielectric properties of this mixed-perovskite solid solutions were observed by transmission electron microscopy, which revealed the existence of complicated ferroelectric domains, suggested that the weak spontaneous magnetization was closely associated with the decrease in the extent of rhombohedral distortion by a partial substitution of $BaTiO_3$ for $BiFeO_3$.