• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2002년도 가을 학술발표회 논문집
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• pp.557-564
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• 2002

One of the primary factors like plate structure In ship is redundancy structure that is comparable with ocean structure and frame structure. The more component material becomes buckling collapsed locally the less structure stiffness becomes accordingly. As a result, by increasing the load distribution of any other subsidiary structure continually component member collapses, therefore the structure could be in danger of collapse. So, in order to interpret this phenomenon precisely, the study on boundary condition of the ship's Plate and post-buckling analysis must be considered. In this study, the rectangular plate is compressed by the in-plane load. Buckling ＆ Ultimate strength characteristics we applied to be the elasto-plasticity large deformation by F.E.M. On this basis, elasto-plasticity of the plain plate are investigated. This study proved elasto-plasticity behaviour of tile ship's plate In accordance with boundary condition based on the series analysis In case of the compressive load operation.

• 대한화학회지
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• 제42권2호
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• pp.161-171
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• 1998

알켄-오존 반응에서 생성된 중간 생성물로써 primary ozonide (POZ),secondary ozonide (SOZ)그리고 carbonyl oxide의 분자구조, vibrational frequencies그리고 infrared(IR)스펙트럼의 세기 등에 대한 이론적 연구를 high level ab initio 양자역학적 방법(CISD,CCSD)을 사용하여 수행하였다. 일반적으로, polarization function은 결합각과 결합길이를 감소시키는 경향을 보였고 반면, electron correlation effect는 결합길이와 결합각을 약간 증가시키는 경향을 보이고 있다. Carbonyl oxide의 분자구조는 zwitterionic form이 diradical form보다 더 안정한 것으로 예측되었으며, 두 형태의 에너지는 차이는 TZ2P CISD level에서 약 22.4 kcal/mol인 것으로 계산되었다. 또한, POZ과 SOZ의 분자구조 및 harmonic vibrational frequencies들을 실험결과와 비교 분석하였으며 IR세기에 근거하여 각 vibrational mode를 assign 하였다.

• 대한기계학회논문집A
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• 제33권10호
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• pp.1108-1118
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• 2009

A Very High Temperature Gas Cooled Reactor (VHTR) has been selected as a high energy heat source of the order of $950^{\circ}C$ for nuclear hydrogen generation, which can produce hydrogen from water or natural gas. A primary hot gas duct (HGD) as a coaxial double-tube type cross vessel is a key component connecting a reactor pressure vessel and an intermediate heat exchanger in the VHTR. In this study, a structural sizing methodology for the primary HGD of the VHTR is suggested in order to modulate a flow-induced vibration (FIV). And as an example, a structural sizing of the horizontal HGD with a coaxial double-tube structure was carried out using the suggested method. These activities include a decision of the geometric dimensions, a selection of the material, and an evaluation of the strength of the coaxial double-tube type cross vessel components. Also in order to compare the FIV characteristics of the proposed design cases, a fluid-structure interaction (FSI) analysis was carried out using the ADINA code.

• Nuclear Engineering and Technology
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• 제52권6호
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• pp.1318-1326
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• 2020

Structural modification in the electrical cabinet is investigated by a proposed procedure that comprises of an experimental, analytical and numerical solution. This research emphasizes the linear dynamic analysis of the cabinet that is studied under the seismic excitation to demonstrate the real behavior of the cabinets in NPP. To this end, an actual electric cabinet is experimentally tested using an impact hammer test which reveals the fundamental parameters of the cabinet. The Frequency-domain decomposition (FDD) method is used to extract the dynamic properties of the cabinet from the experiment which is then used for numerical modeling. To validate the dynamic properties of the cabinet an analytical solution is suggested. The calibrated model is analyzed under the floor response obtained from the Connecticut nuclear power plant structure excited by Tabas 1978 (Mw 7.4) earthquake. Eventually, the grouping effect of the cabinets is proposed which represents the influence on the dynamic modification. This grouping of the cabinets is described more sophisticatedly by the theoretical understating, which results in a significant change in the seismic response. Considering the grouping effects will be helpful in the assessment of the real seismic behavior, design, and performance of cabinets.

• 한국세라믹학회지
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• 제28권9호
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• pp.721-729
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• 1991

SnO2-TiO2(Pt or Pd), as raw material for hydrocarbon gas sensors, was prepared by a coprecipitation method. The SnO2-TiO2-based thick film gas sensors were made by screen printing technique. The titanium dioxide synthesized was shown to be anatase structure from XRD peaks and was transformed to rutile structure between 700$^{\circ}C$ and 1000$^{\circ}C$. Titanium dioxide in SnO2-TiO2 thick films devices plays a very important role in the enhancement of the sensitivity to CH4 and C4H10. In the case of SnO2-TiO2(Pt) sensors, titanium dioxide that was rutile structure enhanced the sensitivity of the thick film to CH4. Platinum added to the raw powder at coprecipitation (as chloroplatinic acid VI hydrate) improved the gas sensitivity to hydrocarbon gases. Therefore, it is expected that the SnO2-TiO2(Pt) thick film sensors fabricated in this experiment could be put into practical use as LPG (primary component : C4H10 and C3H8) and LNG (primary component : CH4) sensors.

• Fisheries and Aquatic Sciences
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• 제21권4호
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• pp.7.1-7.8
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• 2018

In this study, we isolated and characterized the acid-soluble skin collagen of Pacific bluefin tuna (PBT, Thunnus orientalis). The PBT skin collagen was composed of two ${\alpha}$ chains (${\alpha}1$ and ${\alpha}2$) and one ${\beta}$ chain. The denaturation temperature of PBT collagen was low although it was rich in proline and hydroxyproline. The primary structure of PBT skin collagen was almost identical to that of calf and salmon skin collagen; however, it differed with respect to the epitope recognition of the antibody against salmon type I collagen. These results suggest that the primary structure of skin collagen was highly conserved among animal species, although partial sequences that included the epitope structure differed among collagens.

• International Journal of Naval Architecture and Ocean Engineering
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• 제11권2호
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• pp.679-687
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• 2019

This paper presents the autonomous swimming technology developed for an Autonomous Underwater Vehicle (AUV) operating in the underwater jacket structure environment. To prevent the position divergence of the inertial navigation system constructed for the primary navigation solution for the vehicle, we've developed kinds of marker-recognition based underwater localization methods using both of optical and acoustic cameras. However, these two methods all require the artificial markers to be located near to the cameras mounted on the vehicle. Therefore, in the case of the vehicle far away from the structure where the markers are usually mounted on, we may need alternative position-aiding solution to guarantee the navigation accuracy. For this purpose, we develop a sonar image processing based underwater localization method using a Forward Looking Sonar (FLS) mounted in front of the vehicle. The primary purpose of this FLS is to detect the obstacles in front of the vehicle. According to the detected obstacle(s), we apply an Occupancy Grid Map (OGM) based path planning algorithm to derive an obstacle collision-free reference path. Experimental studies are carried out in the water tank and also in the Pohang Yeongilman port sea environment to demonstrate the effectiveness of the proposed autonomous swimming technology.

• Journal of Species Research
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• 제9권1호
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• pp.56-67
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• 2020

Eight new species of two genera Dysidea and Euryspongia (Demospongiae: Dictyoceratida: Dysideidae) are described from Gageodo, Ulleungdo, Geomundo, and Jejudo Islands, Korea. Four new species of the genus Dysidea are differentiated by the fibre structure, cored detritus, and fibre arrangement. Dysidea mureungensis n. sp. is characterized by the honeycomb shape of surface and no distinction between primary and secondary fibres. Dysidea glavea n. sp. differs by large sands cored in fibres and that the membrane easily separates from fibres. Dysidea geomunensis n. sp. has fibres that are thinner than those of D. glavea n. sp.. Dysidea corallina n. sp. is characterized by folded fan shape and the arrangement of secondary fibres. Four new species of the genus Euryspongia are differentiated by the fibre structure, cored detritus, shape of sponge, and fibre arrangement. Euryspongia radicula n. sp. is very different from other species by having regularly arranged fibres. Euryspongia spina n. sp. has a fence-like skeletal structure. Bridged type secondary fibres are arranged near the surface and web types are at the base of fibres. Euryspongia flabellum n. sp. has a very unique wide, thin leaf-like shape. String-like primary fibres of E. linea n. sp. are very unique and cored with large sized sands.

• 한국물환경학회지
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• 제39권3호
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• pp.215-222
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• 2023

Zooplankton are primary consumers in the food web connecting primary producers and predators such as small fish, playing an important role in energy transfer in aquatic ecosystems. Therefore, it is essential to understand the zooplankton community structure in material cycle and energy flow in aquatic ecosystems. Zooplankton in large rivers with a low flow rate would distribute vertically as in lakes. In this study, we collected zooplankton by surface water filtration and vertical haul method with 64 ㎛-mesh plankton net at three stations (ND-1, ND-2, ND-3) in Nakdong River fortnightly from June 2018 to December 2019. Species composition and individual densities were analyzed. All three stations showed differences in relative abundance of zooplankton groups between surface water and vertical integrated water, with the largest difference shown in the deepest station, ND-2. In vertically integrated water at ND-2, the relative abundance of rotifera was low by a maximum of 25% and that of cladocera was high by a maximum of 22% compared to surface water samples. These results indicate that surface water filtration method is not enough to represent the community structure of zooplankton compared to the vertical haul method in large rivers.

• 한국정보처리학회논문지
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• 제6권8호
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• pp.2204-2212
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• 1999

본 논문에서는 허위 경로 문제를 해결하고 지연 시간 정보를 추출해내는 지연 시간 부울법을 이용하여 조합 회로에서 증가적 지연 시간 검사를 수행할 수 있는 방법을 제시한다. 내부 출력단에서 대치되는 내부 입력단의 히스토리를 작성하고 외부 출력단의 활성화 경로를 검사하여 최대 지연 시간을 구한다. 이때 외부 출력단의 히스토리를 참조하여 변형된 지연 시간을 적용시켜 다시 외부 출력단의 최대 지연 시간을 구할 수 있다. 이 방법으로 일단 외부 출력단의 근지연항의 합을 구하면 내부 회로의 지연 시간이 변하더라도 이미 구해 놓은 외부 출력단의 근지연항의 합으로써 빠르고 효율적으로 최대 지연 시간과 입력값을 추출해 낼 수 있다. 회로의 구조가 변경되었을 때 전체 회로를 다시 계산해야 할 필요는 없다. 전체 회로를 검사하여 변경된 구조의 영향을 받아서 다시 계산해야 할 필요가 있는 게이트를 선택하고 이 선택된 게이트만을 계산하여 부분적인 지연 시간 분석을 행할 수 있다. 이러한 증가적 지연 시간 분석은 회로의 지연 시간의 변화 뿐만 아니라 회로 구조의 변화를 고려하였고, 기존의 지연 시간 분석에 비해 회로 설계시 성능 시험 단계에서 생기는 시행 착오의 비용을 줄일 수 있다.