• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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• pp.1415-1424
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• 2009

Measuring dynamic properties of gravel-sized materials demands large specimens. Due to the difficulties in experiment as well as equipment, the dynamic properties of gravel-sized material has rarely been investigated. To realize free-free end condition more properly and stabilize specimen during testing with new specimen support system, a free-free resonant column testing device, which is capable of testing gravel-sized materials and constraining a specimen in free-free boundaries, is developed. We report the calibration of the equipment and preliminary testing results on Jumunjin sand. The testing data are compared with the previous data obtained from the existing fixed-free resonant column test.

• 한국콘텐츠학회논문지
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• 제11권5호
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• pp.474-480
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• 2011

고구려, 백제, 신라 왕조실록에 등장하는 인물 네트워크는 다른 사회 네트워크와는 달리 척도 없는 네트워크 (scale-free network)의 특성이 아닌 정보의 보급, 인터넷 연쇄 편지, 청원 편지 등에서 보여주는 유포 네트워크 (dissemination network) 의 특성을 보여주고 있다. 그러나 이들 세 왕조를 통합한 삼국왕조실록은 사회 네트워크와 마찬가지로 척도 없는 네트워크의 전형적인 특성을 보여주고 있었다. 일반적으로 생명체 네트워크는 척도 없는 네트워크와 계층적 네트워크 (hierarchical network)의 특성을 동시에 가지는데, 삼국왕조실록도 척도 없는 네트워크뿐만 아니라 계층적 네트워크의 특성을 동시에 보여주고 있었다. 네트워크를 기반으로 각 국가의 영토 변화 양상을 분석하였는데, 고구려나 백제와는 달리 신라만의 독특한 양상을 가지는데, 이 양상이 삼국 통일을 이루는 근간을 만든 것으로 분석하였다. 고구려, 백제, 신라의 전반적인 나라 경영, 발전 양상 및 이들 나라의 중심이 되는 왕의 인물 네트워크를 바탕으로 통치 양상을 분석하였다. 본 연구는 삼국 왕조실록에 등장하는 인물을 역사학적 관점이 아닌 실록에 등장하는 인물 네트워크를 기반으로 분석함으로서 새로운 각도에서 해석할 수 있는 가능성을 제시하였다.

• 한국해양환경ㆍ에너지학회지
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• 제8권3호
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• pp.116-121
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• 2005

본 연구에서는 자유표면을 갖는 대규모의 환경유동의 해를 구하는데 있어 비정수압의 효과를 고려하는 새로운 계산 기법을 제시하였다. Sigma 좌표계에서 시간은 전진차분으로, 공간은 중간차분 및 풍상차분을 혼합하여 2단계 해법을 도입하였다. 계산기법의 타당성과 유효성을 검증하기 위하여, 자유표면을 갖는 정상유동과 비정상유동에 대한 전형적인 예를 설정하여 정수압 계산과 비정수압 계산을 수행하고 이들을 비교하였다. 계산결과 복잡한 해저지형을 갖는 자유표면 유동에 있어, 지정수압효과가 무시할 수 없는 유동영역이 존재함이 입증되었으며, MAC기법과 같은 3차원 유체동역학적 기법을 적용하기에는 비경제적인 문제에 대해 본 계산기법이 매우 유효하게 적용될 수 있다는 가능성이 입증되었다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 춘계 학술논문 발표대회
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• pp.126-127
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• 2015

New technologies using a CNC machine to reduce the production cost of free-form buildings are being developed. To produce free-form members with such technologies, a vast free form building should be first divided into multiple panels that can be produced. Considering the curved surface of free-form buildings, the shape and size of divided freeform panels vary, which will lead to a great deal of errors. Currently, the engineers and designers complete the panelizing work through trials and errors even in large-scale projects, which results in increased construction duration and cost. Thus, it is necessary to develop a freeform panelizing technology to maximize the economic effects of free-form concrete member production technology. The purpose of the study is to analyze influence factors on panelizing of free-form buildings, which is a preceding research for development of a panelizing technology. The influence factors drawn will provide a core basis for development of panelizing technologies for free-form buildings.

• 대한금속재료학회지
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• 제48권12호
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• pp.1078-1083
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• 2010

In this study, high temperature oxidation behavior of Alloy 617 was investigated to evaluate the effect of grain size for Alloy 617. The grain size of grain-refined Alloy 617 (GR617) was reduced to $5{\mu}m$ from $71{\mu}m$ for as-received Alloy 617 (AR617) by recrystallization after cold rolling. After high temperature aging, the oxide layers of AR617 and GR617 consisted of $Cr_2O_3$ external oxide scale and $Al_2O_3$ internal oxide. The external oxide scale resulted in a Cr-depleted zone and a carbide free zone below the scale. The depth of the carbide free zone was deeply formed in GR617. On the other hand, the depth of the internal oxide layer in GR617 was shorter than that in AR617. After a 3-point bending test, crack propagation of GR617 was more restricted than that of AR617 because of the different microstructure of the internal oxide.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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• 제10권1호
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• pp.59-68
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• 2004

The sanitary arrangements and Toilets are very important for a barrier-free environment of university education. this paper try to provide basic evaluation of the sanitary arrangements for disabled person in university. To accomplish this purpose this study has analyzed with questionnaire quantitatively and qualitatively the 188 universities. As the result, from the barrier-free environmental evaluation of the sanitary arrangements, the large-scale university and the university with special admission rules for the disabled person are highly evaluated, while the small-scale university and the university without special admission rules are done low.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권7호
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• pp.319-325
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• 2005

In order to analyze ground potential rise of grounding system installed in buildings, the hemispherical grounding simulation system has been designed and fabricated as substantial and economical measures. Ground potential rise(GPR) has been measured and analyzed for shapes of grounding electrode using the system in real time. The system is apparatus to have a free reduced scale for conductor size and laying depth of a full scale grounding system and is constructed so that a shape of equipotential surface is nearly identified a free reduced scale with a real scale when a current flows through grounding electrode. The system was composed of a hemispherical water tank, AC Power supply, a movable potentiometer, and test grounding electrodes. The test grounding electrodes were fabricated through reducing grounding electrode installed in real buildings such as rod type, mesh grid type. When a mesh grid type was associated with a rod type, GPR was the lowest value. The proposed results would be applicable to evaluate GPR in the grounding systems. and the analytical data can be used 0 stabilize the electrical installations and prevent the electrical disasters.

• Journal of Electrochemical Science and Technology
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• 제8권3호
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• pp.215-221
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• 2017

The electroless plating process largely consists of substrate cleaning, seed formation (activator formation), and electroless plating. The most widely used activator in the seed formation step is Pd, and Sn ions are used to facilitate the formation of this Pd seed layer. This is problematic because the Sn ions interfere with the reduction of Cu ions during electroless plating; thus, the Sn ions must be removed by a hydrochloric acid cleaning process. This method is also expensive due to the use of Pd. In this study, Cu electroless plating was performed by forming a seed layer using a silver nanosol instead of Pd and Sn. The effects of the Ag nanosol concentration in the pretreatment solution and the pretreatment time on the thickness and surface morphology of the Cu layer were investigated. The degrees of adhesion to the substrate were similar for the electroless-plated Cu layers formed by conventional Pd activation and those formed by the Ag nanosol.

• 한국산학기술학회논문지
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• 제15권2호
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• pp.1109-1117
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• 2014

본 논문에서는 S형상함수를 이용한 점진기능재료 나노-스케일 판의 자유진동 특성에 미치는 비국소 탄성 이론의 효과에 대하여 연구하였다. 비국소 탄성 이론은 미소 규모 효과를 고려할 수 있고 S형상함수는 점진기능재료의 정확한 특성변화를 고려할 수 있다. 이러한 이론을 이용하여 나노-스케일 판의 고유진동수에 미치는 비국소 이론의 효과를 제시하였고, 국소 탄성이론과의 관계를 수치해석 결과를 통하여 고찰하였다. 또한 (i) 거듭제곱 지수, (ii) 비국소 계수, (iii) 탄성계수 비 그리고 (iv) 나노-스케일 판의 두께 및 형상 변화 등이 나노-스케일 판의 무차원 진동수에 미치는 효과에 대하여 관찰하였다. 본 연구의 결과를 검증하기 위해 참고문헌의 결과들과 비교 분석하였으며 해석결과는 참고문헌의 결과들과 잘 일치함을 알 수 있었다. 비국소 이론에 의한 나노-스케일 판의 진동에 관한 연구는 향후 관련연구에 비교자료로 활용될 수 있을 것이다.

• Computers and Concrete
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• 제24권6호
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• pp.579-586
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• 2019

In this research paper, the free vibrational behavior of the simply supported FG nano-plate is studied using the nonlocal two variables integral refined plate theory. The present model takes into account the small scale effect. The effective's properties of the plate change according to the power law variation (P-FGM). The equations of motion of the system are determined and resolved via Hamilton's principle and Navier procedure, respectively. The validity and efficiency of the current model are confirmed by comparing the results with those given in the literature. At the last section, several numerical results are presented to show the various parameters influencing the vibrational behavior such as the small-scale effect, geometry ratio, material index and aspect ratio.