• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.6
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• pp.744-750
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• 2015

In this paper, development of mobile robot for the inspection of hull surface was mentioned. In the sea, it is difficult to proceed with the visual inspection of hull side and thus mobile robot for checking the status could be run with strap-on its surface. To do this, permanent magnet module to generate magnetic force between hull surface and mobile robot, and structure to minimize variance of the force under curvature circumstance were considered on the design. Based on the design, mobile robot with four NdFeB, four driving wheels and image aquisition module was applied. Load experiment to check the adhesive force, slip test during stop state and driving test to measure driving speed were executed. From the experiments 13 Kgf adhesive force was obtained and slip was not happened until 8 Kgf load on the inclined plate. Driving speed of mobile robot was measured at 0.82 m/s corresponding to 6.5 ampere. We confirmed the effectiveness of developed mobile robot by experiments to check its characteristics.

• 보존과학연구
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• s.33
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• pp.125-148
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• 2012

The Octagonal nine storied pagoda of Woljeongsa Temple consists mainly of granite with the rockforming minerals quartz, plagioclase, microcline, and biotite. The surface of the stone stupa is light brown that has been discolored by the rust from the metal ornament and aids. The surface of the stylobate and roof stone is colonized by biological contaminants. Therefore, a comprehensive deterioration diagnosis was carried out in this study, and conservation treatment was conducted. It was proven that the $Fe^{2+}$ yield increases depending on the count of poultice used with oxalic acid, but the $Mg^{2+}$, $Al^{3+}$, and $Ca^{2+}$ yields were marginal following the preliminary test. Therefore, the use of poultice is an effective way of removing the rust, and only marginally influences the rock. The biological contaminants were removed through dry cleaning, and the soil located under the contaminants was removed through wet cleaning. Based on this, the dry and wet cleaning of all the biological contaminants, and the use of poultice with oxalic acid, were done to remove the rust. For the conservation treatment of the metal ornament, the rust was removed through physical cleaning, and anticorrosion treatment was performed on the iron ornament using Renaissance wax and copper ornament by BTA.

• Annual Conference on Human and Language Technology
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• 1999.10e
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• pp.441-446
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• 1999

본 연구는 접속사를 통한 텍스트 통합 과정이 논리적 추론 종류에 따라 다른 정보처리 과정 혹은 다른 종류의 단원적 구조(modular structure in language processing)에 의해 처리되는지를 조사하기 위해 실시되었다. 또한, 접속사를 통한 추론 과정이 실어증의 증상 종류에 따라 다른 종류의 언어정보처리 손상이 있는지를 평가하기 위해 실시되었다. 실험에 참가한 환자는 이해성 실어증환자(Wernicke aphasic), 전반성 실어증 환자(Global aphasic), 표현성 실어증 환자(Broca aphasic) 등이었다. en 종류의 과제를 이용하였다. 한 과제는 앞 뒤 문장을 논리적 관계성을 표현하는 접속사를 채워 넣는 과제였고 다른 과제는 접속사가 포함된 텍스트가 옳은지를 판단하는 정오 판단 과제였다. 실험재료 문장에 사용된 접속사는 추가적인 정보를 제공하는 '그리고'와 대등 관계를 나타내는 '그러나' 및 인과 관계를 표현하는 '그래서' 였다. 이 세 종류의 접속사는 각기 다른 논리적 관계성을 나타낸다. 실험 결과는 실어증 환자가 전반적으로 채워 넣기 과제에서 보다는 정오 판단 과제에서 더 많은 실수를 보였으며, 표현성 실어증 환자보다는 이해성 실어증 환자가 더 많은 오류를 보였다. 또한, 세 종류의 접속사 중에 '그리고'가 표함된 텍스트에서 더 많은 실수를 보였다. 이 연구에서 나타난 흥미 있는 결과는 표현성 실어증 환자는 '그러나' 접속사가 포함된 텍스트에서의 수행이 '그래서'가 포함된 경우에서보다 좋은 반면에 전반성 실어증 환자는 '그래서'를 포함하는 텍스트에서의 수행이 '그러나'를 포함하는 텍스트에서의 수행이 더 우수해서 이중해리(double dissociation)가 나타난다는 사실이다. 이 결과는 선후 문장이 어떤 종류의 논리적 관계성을 지니는가에 따라 다른 종류의 정보처리가 진행된다는 것을 암시하는 결과이다.>$\textrm{cm}^2$.。C로 비교적 양호한 초전박막의 전기적 특성을 나타내었다.(Mg+Fe)비를 갖고 전자에 비해 Al이 풍부한 환경에서 생성되었으며, 따라서 활석과 연관되지 않은 녹니석은 생성시 광체와 인접한 화강아질 편마암에 의해 주로영향을 받았을 것으로 생각된다. 녹니석의 이러한 2가지 화학조성상의 경향은 녹니석과 공존하는 운모류나 각섬석류들의 화학분석결과와도 잘 일치한다. 이러한 결과는 이 지역의 활석 광상이 초염기성암 기원의 사문암이 열수변질작용을 받아 생성되었음을 명확하게 지시하며, 따라서 활석 광석내에 존재하는 녹니석은 활석의 근원 광물로서 녹니석편암 및 녹니석 편마암 매의 녹니석이 활석화되고 남은 잔존광물이 아니라, 주변암에 의해 성분상의 영향을 받은 열수와 사문암과의 변질교대작용에 의한 활석화과정 중에 주로 생성된 것으로 추정된다. 이러한 결과는 연구지역의 활석광상이 초염기성암의 사문암화 작용과 활석화 작용의 두 가지 변질작용에 의해 형성되어졌음을 알려준다.농도 증가 없이 폐 조직에 약 50배 정도의 고농도 cisplatin을 투여할 수 있었으며, 또한 분리 폐 관류 시 cisplatin에 의한 직접적 폐 독성은 발견되지 않았다이 낮았으나 통계학적 의의는 없었다[10.0%(4/40) : 8.2%(20/244), p>0.05]. 결론: 비디오흉강경술에서 재발을 낮추기 위해 수술시 폐야 전체를 관찰하여 존재하는 폐기포를 놓치지 않는 것이 중요하며, 폐기포를 확인하지 못한 경우와 이차성 자연기흉에 대해서는 흉막유착술에 더 세심한 주의가 필요하다는 것을 확인하였다. 비디오흉강경수술은 통증이 적고, 입원기간이 짧고, 사회로의 복귀가 빠르며, 고위험군에 적용할 수 있고, 무엇보다도 미용상의 이점이 크다는 면에서 자연기흉에 대해 유용한 치료방법임에는 틀림이 없으나 개흉술에 비해 재발율이 높고 비용이 비싸다는 문제가 제기되고 있는 만큼

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.5
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• pp.339-349
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• 2020

Double-leaf blast-resistant doors consisting of steel box and slab are application-specific structures installed at the entrances of protective facilities. In these structural systems, certain spacing is provided between the door and wall. However, variation in the boundary condition and structural behavior due to this spacing are not properly considered in the explosion analysis and design. In this study, the structural response and failure behavior based on two variables such as the spacing and blast pressure were analyzed using the finite element method. The results revealed that the two variables affected the overall structural behavior such as the maximum and permanent deflections. The degree of contact due to collision between the door and wall and the impact force applied to the door varied according to the spacing. Hence, the shear-failure behavior of the concrete slab was affected by this impact force. Doors with spacing of less than 10 mm were vulnerable to shear failure, and the case of approximately 15-mm spacing was more reasonable for increasing the flexural performance. For further study, tests and numerical research on the structural behavior are needed by considering other variables such as specifications of the structural members and details of the slab shear design.

• Membrane Journal
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• v.26 no.2
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• pp.116-125
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• 2016

This study described a synthesis of MF having a arsenic removal characteristics and the fundamental research was performed about the simultaneous removal system of both As(III) and As(V) ions with the composite nanofiber membrane (PMF) based on PVdF and MF materials for the water-treatment application. From the TEM analysis, the shape and structure of MF materials was investigated. The mechanical strength, pore-size, contact angle and water-flux analysis for the PMF was performed to investigate the possibility of utilizing as a water treatment membrane. From these results, the PMF11 showed the highest value of mechanical strength ($232.7kgf/cm^2$) and the pore-diameter of composite membrane was reduced by introducing the MF materials. In particular, their pore diameter decreased with an increase of iron oxide composition ratio. The water flux value of PMF was improved about 10 to 60% compared with that of neat PVdF nanofiber membranes. From the arsenic removal characterization of prepared MF materials and PMF, it was shown the simultaneous removal characteristics of both As(III) and (V) ions, and the MF01, in particular, showed the highest adsorption-removal rate of 93% As(III) and 68% As(V), respectively. From these results, prepared MF materials and PMF have shown a great potential to be utilized for the fundamental study to improve the functionality of water treatment membrane.

• Journal of the Korea Concrete Institute
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• v.24 no.3
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• pp.315-322
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• 2012

Alkali-activated slag (AAS) is the most obvious alternative materials that can replace OPC. But, AAS industrial usage as a structural material should be evaluated for its durability. Carbonation resistance is one of the most important factors in durability evaluation. Test results for 18 slag-based mortars activated by sodium silicate and 6 OPC mortars were obtained in this study to verify the carbonation property. Main variables considered in the study were flow, compressive strength before and after carbonation, and carbonation depth. Mineralogical and micro-structural analysis of OPC and AAS specimens prior to and after carbonation was conducted using XRD, TGA, FTIR FE-SEM. Test results showed that CHS was major hydration products of AAS and, unlike OPC, no other hydration products were found. After carbonation, CSH of hydration product in AAS turned into an amorphous silica gel, and alumina compounds was not detected. From the analysis of the results, it was estimated that the micro-structures of CSH in AAS easily collapsed during carbonation. Also, the results showed that this collapse of chemical chain of CSH lowered the compressive strength of concrete after carbonation. By increasing the dosage of activators, carbonation resistance and compressive strength were effectively improved.

• Journal of the Korean Geotechnical Society
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• v.32 no.11
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• pp.5-19
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• 2016

This paper presents the results from three-dimensional finite element (FE) analysis undertaken to provide insight into the lateral behaviors of piled gravity base foundation (GBF) for offshore wind turbine. The piled GBF was originally developed to support the gravity based foundation in very soft clay soil. A GBF is supported by five piles in a cross arrangement to achieve additional vertical bearing capacity. This study considered four different cases including a) single pile, b) three-by-three group pile (with nine piles), c) cross-arrangement group pile (with five piles), and d) piled GBF. All the cases were installed in homogenous soft clay soil with undrained shear strength of 20 kPa. From the numerical results, p-y curves and thus P-multiplier was back-calculated. For the group pile cases, the group effect decreased with increasing the number of piles. Interestingly, for the piled GBF, the P-multipliers showed a unique trend, compared to the group pile cases. This study concluded that the global lateral behaviour of the piled GBF was influenced strongly by the interaction between GBF and contacted soil surface.

• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.77-78
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• 2006

최근 flexible OLED의 구동에 사용하기 위한 유기박막트랜지스터(Organic Thin Film Transistor, OTFT)의 연구에서는 용매에 용해되어 spin coating이 가능한 재료의 개발에 관심을 두고 있다. 현재 pentacene으로는 아직 spin coating으로 제작할 수 있는 상용화된 제품이 없고 spin coating이 가능한 활성층 물질(active material)로 P3HT가 쓰이고 있다. 본 연구에서는 용해 가능한 P3HT 활성층 물질과 여러 종류의 용해 가능한 게이트 절연물(gate insulator, Gl)을 사용하여 안정된 소자를 구현할 수 있는 공정을 개발하는 목적으로 metal-insulator-semironductor(MIS) 소자를 제작하여 C-V 특성을 측정하고 분석하였다. 먼저 7mm${\times}$7mm 크기의 pyrex glass 시편 위에 바닥 전극으로 $1600{\AA}$ Au을 증착하고 spin coating 방식을 이용하여 PVP, PVA, PVK, BCB, Pl의 5종류의 게이트 절연층을 각각 형성하였고 그 위에 같은 방법으로 P3HT를 코팅하였다. P3HT 코팅 시 bake 공정의 유무와 spin rpm의 변화에 따른 P3HT의 두께를 측정하였다. Gl의 종류별로 주파수에 따른 capatltancc를 측정하여 비교, 분석하였다. C-V 측정 결과 PVP, PVA, PVK, BCB, Pl의 단위 면적당 capacitance 값은 각각 1.06, 2.73, 2.94, 3.43, $2.78nF/cm^2$로 측정되었다. Threshold voltage, $V_{th}$는 각각 -0.4, -0.7, -1.6, -0.1, -0.2V를 나타냈다. 주파수에 따른 capacitance 변화율을 측정한 결과 Gl 물질 모두 주파수가 높을수록 capacitance가 점점 감소하는 경향을 보였으나 1${\sim}$2nF 이내의 범위에서 작은 변화율만 나타냈다. P3HT의 두께와 bake 온도를 변화시켜 C-V 값을 측정한 결과 차이는 없었다. FE-SEM으로 관찰한 결과에서도 두께나 온도에 따른 P3HT의 표면 morphology 차이를 확인할 수 없었다. 본 연구에서 PVK와 P3HT의 조합이 수율(yield)면에서 가장 안정적이면서 $3.43\;nF/cm^2$의 가장 높은 capacitance 값을 나타내고 $V_{th}$ 값 또한 -1.6V로 가장 낮은 값을 보였다.

• Journal of Environmental Health Sciences
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• v.35 no.6
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• pp.517-525
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• 2009

The water quality of Lake Shihwa had been rapidly deteriorating since 1994 due to wastewater input from the watersheds, limited water circulation and the lack of a wastewater treatment policy. In 2000, the government decided to open the tidal embankment and make a comprehensive management plan to improve the water quality, especially inflowing stream water around Shihwa and Banwol industrial complex. However, the water quality and microbial community have not as yet been fully evaluated. The purpose of this study is to investigate the influent water quality around the industrial area based on chemical and biological analysis, and collected surface water sample from the Siheung Stream, up-stream to down-stream through the industrial complex, Samples were collected in July 2009. The results show that the downstream site near the industrial complex had higher concentrations of heavy metals (Cu, Mn, Fe, Mg, and Zn) and organic matter than upstream sites. A combination of DGGE (Denaturing Gradient Gel Electrophoresis) gels, lists of K-WQI (Korean Water Quality Index), cluster analysis, MDS (Multi-Dimensional Scaling) and PCA (Principal Component Analysis) has demonstrated clear clustering between Siheung stream 3 and 4 and with a high similarity and detected metal reducing bacteria (Shewanella spp.) and biodegrading bacteria (Acinetobacter spp.). These results suggest that use of both chemical and microbiological marker would be useful to fully evaluate the water quality.

• The Journal of the Petrological Society of Korea
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• v.26 no.4
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• pp.311-325
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• 2017

Peridotite xenoliths in middle Miocene alkaline basalt from the Mt. Baekdu area are mainly anhydrous spinel lherzolites, displaying coarse-grained protogranular texture. These xenoliths have late-stage secondary orthopyroxene replacing olivine as the metasomatic mineral and glass formed along the grain boundaries. The studied xenoliths are characterized by the high $Mg{\sharp}[=100{\times}Mg/(Mg+Fe_{total})$ atomic ratio] of olivine, orthopyroxene and clinopyroxene (89~92) and the $Cr{\sharp}[=100{\times}Cr/(Cr+Al)$ atomic ratio] of spinel (10~29). Based on major-element data, the studied xenoliths are similar to those from the abyssal peridotites. Clinopyroxenes of the xenoliths are mostly enriched in incompatible trace elements, exhibiting two types of REE patterns: (1) LREE-depleted with $(La/Yb)_N$ of 0.1~0.2 and $(La/Ce)_N$ of 0.4~0.8. (2) LREE enriched with $(La/Yb)_N$ of 2.2~3.8 and $(La/Ce)_N$ of 1.2~1.6. The calculated equilibrium temperatures and oxygen fugacities resulted in $920{\sim}1050^{\circ}C$ and ${\Delta}fO_2(QFM)=-0.8{\sim}0.2$, respectively. It is suggested that the Mt. Baekdu peridotite xenoliths represent residues left after variable degrees of melt extraction(less than 15 vol%), which was subsequently subjected to different degrees of modal/cryptic metasomatism by silica- and LREE-enriched fluids (or melts).