• 건축역사연구
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• 제20권1호
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• pp.61-75
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• 2011

This study aims to investigate the changing aspects about research methodology of stone pagoda from the period of Japanese colonial to now. There were the differences in purpose, method and analysis of the research according to each period. In Japanese colonial period, the purpose of research was to make lists of almost stone pagodas in Korea. Following this, Japanese researchers conducted detailed research for academic purpose. They took measurements of stone pagodas and made drawings. After liberation the research was focused on the relics contained in pagodas. They proceeded to investigate the inner relics in order to attract the attention of the people. In the late 1900's, the repair works of cultural heritages were increased. Many reports of the repair works were released and sent to administration offices. The reports contained the change aspects of situation between before work and after with drawings or simple investigation documents. In the 1990's, the restoration works for important stone pagodas were started by the National Research Institute of Cultural Heritage. Since then, researches from various way - architectural and conservational researches about historical interpretation, shape, structure, proportion, technique, etc. - progressed for careful restoration and accurate study. In Recent years, various professional organizations(in the field of structure, physics, chemistry, biology, lithology, etc.) started to join the researches. Researches conducted studies directly with the stone pagodas, as well as conducting indirect studies with the stone pagodas, such as the structural stability of stone pagodas, the characteristics of rock, and conservation chemicals. Today the research project 'The preservation project of stone cultural property' is being conducted by the National Research Institute of Cultural Heritage. The purpose of this project is to gain more detailed and accurate investigation documents to be provided for the people. In conclusion, researches from various fields must be included in the research. Furthermore, a synthetic study should be done through comparing similar characteristics or different characteristics among many research results.

• 대한지리학회지
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• 제38권1호
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• pp.70-86
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• 2003

이 연구는 안동의 이른바 음택명당 풍수 경관에 대하여 조사하여 그 형태와 특징을 살펴보고자 한다. 안동문화원에서 펴낸 $\ulcorner$안동의 분묘$\lrcorner$에 나오는 분묘와 예천의 일부 묘지를 대부분 야외조사하고, 이 중에서 형기론적 입장에서 나타난 다양한 명당의 특징을 1:25,000지형도 상에서 기술한다. 안동지역은 낙동강, 반변천, 길안천의 수많은 지류가 흐르고 그 주위에 낮은 구릉, 완만한 사면 및 높은 배후 산지가 전개되며 수많은 명당이 입지한다고 알려져 왔다. 연구 결과는 다음과 같다. 안동의 경우는 날짐승(봉, 학, 꿩), 꽃(모란, 연꽃, 칡넝쿨), 길짐승(닭), 들짐승(거북, 뱀). 물건(등잔, 가마솥, 밥상), 용, 달 등의 형기론적 명당이 나타나며, 이들 형태는 크게 낙동강 본류 이북 쪽에 집중한다. 이들 명당은 고도 상으로 해발고도 100m∼400m 부근에 대부분 입지한다. 이들 명당의 공통된 형태적 특징은 반개방성, 중첩성. 안정성. 조화성, 균형성이다. 형태 상의 이러한 특징은 풍수지리의 원리를 오늘날의 입지 선정에 적용할 수 있는 근거를 갖게 하는 것이다.

• Corrosion Science and Technology
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• 제2권2호
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• pp.68-74
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• 2003

The effects of Niobium on the structure and properties(especially electric properties) of passive film of Zirconium alloys in pH 8.5 buffer solution are examined by the photo-electrochemical analysis. For Zr-xNb alloys (x = 0, 0.45, 1.5, 2.5 wt%), photocurrent began to increase at the incident energy of 3.5 ~ 3.7 eV and exhibited the $1^{st}$ peak at 4.3 eV and the $2^{nd}$ peak at 5.7 eV. From $(i_{ph}hv)^{1/2}$ vs. hv plot, indirect band gap energies $E_g{^1}$= 3.01~3.47 eV, $E_g{^2}$= 4.44~4.91 eV were obtained. With increasing Nb content, the relative photocurrent intensity of $1^{st}$ peak significantly increased. Compared with photocurrent spectrum of thermal oxide of Zr-2.5Nb, It was revealed that $1^{st}$ peak in photocurrent spectrum for the passive film formed on Zr-Nb alloy was generated by two types of electron transitions; the one caused by hydrous $ZrO_2$ and the other created by Nb. Two electron transition sources were overlapped over the same range of incident photon energy. In the photocurrent spectrum for passive film formed on Zr-2.5Nb alloy in which Nb is dissolved into matrix by quenching, the relative photocurrent intensity of $1^{st}$ peak increased, which implies that dissolved Nb act as another electron transition source.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.75.2-75.2
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• 2013

Atomic layer deposition (ALD), utilizing self-limiting surface reactions, could offer promising perspectives for future efficient energy conversion devices. The capabilities of ALD for surface/interface modification and construction of novel architectures with sub-nanometer precision and exceptional conformality over high aspect ratio make it more valuable than any other deposition methods in nanoscale science and technology. In the context, a variety of researches on fabrication of active materials for energy conversion applications by ALD are emerging. Among those materials, one-dimensional nanotubular titanium dioxide, providing not only high specific surface area but also efficient carrier transport pathway, is a class of the most intensively explored materials for energy conversion systems, such as photovoltaic cells and photo/electrochemical devices. The monodisperse, stoichiometric, anatase, TiO2 nanotubes with smooth surface morphology and controlled wall thickness were fabricated via low-temperature template-directed ALD followed by subsequent annealing. The ALD-grown, anatase, TiO2 nanotubes in alumina template show unusual crystal growth behavior which allows to form remarkably large grains along axial direction over certain wall thickness. We also fabricated dye-sensitized solar cells (DSCs) introducing our anatase TiO2 nanotubes as photoanodes, and studied the effect of blocking layer, TiO2 thin films formed by ALD, on overall device efficiency. The photon convertsion efficiency ~7% were measured for our TiO2 nanotubebased DSCs with blocking layers, which is ~1% higher than ones without blocking layer. We also performed open circuit voltage decay measurement to estimate recombination rate in our cells, which is 3 times longer than conventional nanoparticulate photoanodes. The high efficiency of our ALD-grown, anatase, TiO2 nanotube-based DSCs may be attributed to both enhanced charge transport property of our TiO2 nanotubes photoanode and the suppression of recombination at the interface between transparent conducting electrode and iodine electrolytes by blocking layer.

• 정보처리학회논문지D
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• 제16D권1호
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• pp.43-54
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• 2009

본 연구의 목적은 모바일 광고에 대한 사용자의 광고가치 인식과 실제 응답의도에 영향을 미치는 변수들을 탐색하고, 인과관계를 분석하는 것이다. 종속변수인 사용자 응답의도와 독립변수 간의 관계적 유의성을 검증하기 위해, Ducoffe(1996)의 광고효과 모형을 기저모형으로 채택하여 연구모형 및 가설을 설정하였다. 주요 독립변수는 유희성, 조작편리성, 정보유용성, 경제성이며, 매개변수로 사용자 광고가치를 개념화 하였다. 특히, 구조모형 경로분석과 조절집단 차이검증 분석을 통해 최적의 연구모형을 도출하였고, 연령별 집단 특성을 규명하기 위해 연령을 조절변수로 선정하여 평가하였다. 본 연구는 모바일 광고의 고유한 특성에 대해, 지금까지 비중 있게 다루지 않았던 광고가치라는 매개변수의 역할과 연령별 차이검증을 실시하였다는 점에서 학술적 그리고 실용적 가치가 있다. 345개 표본을 대상으로 한 설문조사를 바탕으로 실증 분석을 수행하여 연구가설을 검증한 결과, 조작편리성을 제외한 모든 변수의 유의성이 판명되었고, 연령별 집단 간 상이한 결과가 도출되었다.

• Smart Structures and Systems
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• 제7권5호
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• pp.379-392
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• 2011

This paper presents a multi-functional system, consisting of a magnetorheological (MR) damper and an electromagnetic induction (EMI) device, and its applications in stay cables. The proposed system is capable of offering multiple functions: (1) mitigating excessive vibrations of cables, (2) estimating cable tension, and (3) harvesting energy for wireless sensors used health monitoring of cable-stayed bridges. In the proposed system, the EMI device, consisting of permanent magnets and a solenoid coil, can converts vibration energy into electrical energy (i.e., induced emf); hence, it acts as an energy harvesting system. Moreover, the cable tension can be estimated by using the emf signals obtained from the EMI device. In addition, the MR damper, whose damping property is controlled by the harvested energy from the EMI device, can effectively reduce excessive cable vibrations. In this study, the multi-functionality of the proposed system is experimentally evaluated by conducting a shaking table test as well as a full-scale stay cable in a laboratory setting. In the shaking table experiment, the energy harvesting capability of the EMI device for wireless sensor nodes is investigated. The performance on the cable tension estimation and the vibration mitigation are evaluated using the full-scale cable test setup. The test results show that the proposed system can sufficiently generate and store the electricity for operating a wireless sensor node twice per day, significantly alleviate vibration of a stay cable (by providing about 20% larger damping compared to the passive optimal case), and estimate the cable tension accurately within a 2.5% error.

• 동양고전연구
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• 제36호
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• pp.85-104
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• 2009

본 연구는 "논어(論語)"라는 커뮤니케이션 텍스트에서 커뮤니케이터, 수용자, 메시지 등 세 가지 커뮤니케이션 요소를 축으로 하여, 커뮤니케이션 속성의 근거를 찾고자 한 것이다. 여기에는 기존 논어 관련 커뮤니케이션학적 연구의 한계 극복과 학제간 연구의 당위성 및 필요성 제고 의도 또한 포함되고 있다. "논어"가 커뮤니케이션 텍스트인 이유는 문답이라는 인간의 대표적인 커뮤니케이션 방식 사용, 학문 정치 도덕 등과 같은 생활세계의 커뮤니케이션 현상이라는 콘텐츠 특성, 후세에 끼친 영향력이 매우 크기 때문이다. 기존 논어 관련 커뮤니케이션 학적 연구의 문제들은 연구 대상과 연구틀 간 학문적 정합성 논의가 미흡하고, 시론적 속성 기축성(基軸性) 배제 등이 있다. 때문에 본 연구방식을 사용하면 특정 주제 중심의 텍스트 발췌 및 그 재해석을 통해 해결 가능할 것이다. "논어"속에서의 커뮤니케이션 속성은 신실한 윤리성과 논리 및 실천력 등 커뮤니케이터의 요건이 있고, 그리고 이를 토대로 한 도덕적 인간의 이상형으로서 군자(君子) 등이 있다. 또한 어떠한 상황에서도 적절한 메시지 구사 능력 및 선별 판단 능력 그리고 상호 커뮤니케이션 상황의 주도력 등과 같은 수용자 필요조건, 윤리와 이치에 맞으면서 반드시 실천되어야 하는 커뮤니케이션 윤리 실천의 객체인 메시지의 덕목 등이 있다.

• Advances in nano research
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• 제13권1호
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• pp.97-111
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• 2022

In the present article, silica nanoparticles (SNPs) were exploited to improve the tribological and mechanical properties of vinyl ester/glass fiber composites. To the best of our knowledge, there hasn't been any prior study on the wear properties of glass fiber reinforced vinyl ester SiO₂ nanocomposites. The wear resistance is a critical concern in many industries which needs to be managed effectively to reduce high costs. To examine the influence of SNPs on the mechanical properties, seven different weight percentages of vinyl ester/nano-silica composites were initially fabricated. Afterward, based on the tensile testing results of the silica nanocomposites, four wt% of SNPs were selected to fabricate a ternary composite composed of vinyl ester/glass fiber/nano-silica using vacuum-assisted resin transfer molding. At the next stage, the tensile, three-point flexural, Charpy impact, and pin-on-disk wear tests were performed on the ternary composites. The fractured surfaces were analyzed by scanning electron microscopy (SEM) images after conducting previous tests. The most important and interesting result of this study was the development of a nanocomposite that exhibited a 52.2% decrease in the mean coefficient of friction (COF) by augmenting the SNPs, which is beneficial for the fabrication/repair of composite/steel energy pipelines as well as hydraulic and pneumatic pipe systems conveying abrasive materials. Moreover, the weight loss due to wearing the ternary composite containing one wt% of SNPs was significantly reduced by 70%. Such enhanced property of the fabricated nanocomposite may also be an important design factor for marine structures, bridges, and transportation of wind turbine blades.

• Tribology and Lubricants
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• 제37권6호
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• pp.253-260
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• 2021

Metal pipes are used in a wide range of applications, from plumbing systems of large construction sites to small devices such as medical tools. When a liquid is enforced to flow through a metal pipe, a higher flow rate is beneficial for higher efficiency. Using high pressures can enhance the flow rate yet can be harmful for medical applications. Thus, we consider an optimal geometrical design to increase the flow rate in medical devices. In this study, we focus on cannulas, which are widely used small metal pipes for surgical procedures, such as liposuction. We characterize the internal flow rate driven by a negative pressure and explore its dependence on the key design parameters. We quantitatively analyze the suction characteristics for each design variable by conducting computational fluid dynamics simulations. In addition, we build a suction performance measurement system which enables the translational motion of cannulas with pre-programmed velocity for experimental validation. The inner diameter, section geometry, and hole configuration are the design factors to be evaluated. The effect of the inner diameter dominates over that of section geometry and hole configuration. In addition, the circular tube shape provides the maximum flow rate among the elliptical geometries. Once the flow rate exceeds a critical value, the rate becomes independent of the number and width of the suction holes. Finally, we introduce a slippery liquid-infused nanoporous surface (SLIPS) coating using nanoparticles and hydrophobic lubricants that effectively improves the flow rate and antifouling property of cannulas without altering the geometrical design parameter.

• Composites Research
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• 제20권6호
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• pp.1-7
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• 2007

본 연구에서는 팽창흑연/탄소섬유 혼합 보강 전도성 고분자 복합재료를 2단계 성형 공법으로 제조하였으며, 탄소섬유의 첨가가 전도성 고분자 복합재료의 전기적, 기계적 특성에 미치는 영향을 고찰하였다. 전도성 충진재들은 고분자 수지와 기계적으로 혼합되었으며 이를 통하여 복합재료가 전기적 특성을 가지도록 하였다. 팽창흑연은 입자 간 접촉 면적이 넓기 때문에 복합재료 내 전도성 네트워킹의 형성에 매우 유리하지만, 팽창흑연과 고분자 수지만을 사용하여 상기 공정으로 복합재료를 제조할 경우 우수한 기계적 강도를 얻기가 어렵다. 따라서 이를 보완하기 위하여 탄소섬유를 복합재료에 첨가하였으며 전기적 기계적 물성을 바탕으로 탄소섬유의 혼합 비율을 최적화하였다. 굽힘 강도는 탄소섬유의 충친 비율이 증가할수록 섬유에 의한 강화 효과에 의하여 증가 하지만, 32wt.% 이상에서는 오히려 감소하였다. 이는 여분의 탄소섬유들이 공극을 발생시켜 응력집중이 발생하기 때문으로 판단된다. 전기 전도도는 탄소섬유의 비율이 증가할수록 전도성 공백이 발생하고 팽창흑연의 전도성 네트워킹이 저해되기 때문에 계속 감소한다.