• Journal of Convergence for Information Technology
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• v.8 no.5
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• pp.95-100
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• 2018

The metal oxide/graphene nanocomposites are promising functional materials for high capacitive electrode material of secondary batteries, and high sensitive material of high performance gas sensors. In this study, vanadium dioxide($VO_2$) nanostructrures were grown on CVD graphene which was synthesized on Cu foil by thermal CVD, and exfoliated graphene which was exfoliated from highly oriented pyrolytic graphite(HOPG) using a vapor transport method. As results, $VO_2$ nanostructures on CVD graphene were grown preferential growth on abundant functional groups of graphene grain boundaries. The functional groups are served to nucleation site of $VO_2$ nanostructures. On the other hand, 2D & 3D $VO_2$ nanostructures were grown on exfoliated graphene due to uniformly distributed functional groups on exfoliated graphene surface. The characteristics of morphology controlled growth of $VO_2$/graphene nanocomposites would be applied to fabrication process for high capacitive electrode materials of secondary batteries, and high sensitive materials of gas sensors.

• 대한공업교육학회지
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• v.33 no.2
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• pp.154-169
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• 2008

The purpose of this study was to develop learning model turtle boat of teaching-learning materials in order for the students to enhance knowledge, skill and attitude and give interest in transportation technology, and also to recognize the legacy of Korean history. The model turtle boat was developed through three major phases; preparation, development and improvement. The main results of this study were as follows: First, the model turtle boat was developed for students to cultivate design, fabrication, process abilities, and also technological literacy by experimenting and fabricating for themselves. Second, the learning model turtle boat developed is equipped with the sail using natural energy, the linkage and screw applying a mechanical energy and solar cell using solar energy among driving energy. Third, in order to increase interest and attitude regarding a ship in transportation technology, the model turtle boat was developed for students to be able to operate with wireless transceiver on water. Fourth, the model turtle boat was developed to apply the teaching and learning materials for the classes of experiment and practice in primary and secondary schools.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.5
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• pp.173-181
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• 2013

This paper proposes a heuristic optimal solution of multicommodity transportation problem. The proposed algorithm has 3 steps. First the proposed algorithm transforms multicommodity transshipment problem to a general transportation problem, but if the problem is a multicommodity transportation problem, it is not transformed. And the multicommodity is disassembled to a single commodity. Second if it is a multicommodity transportation problem, the algorithm selects the minimum cost according to commodity, on the other hand if it is a multicommodity transshipment problem, the algorithm directly selects the minimum cost based on demand area. And the algorithm assigns carloadings to be satisfied the supply and demand quantity. The algorithm repeats these processes until a given demand quantity is satisfied. Last if it has a condition that is able to reduce the transportation expense, the proposed algorithm controls the assignment quantity of the initial value that got from the step 2. The proposed algorithm was applied to two multicommodity transportation problem and three multicommodity transshipment problem and it got more good result than an existing linear programming method.

• Journal of Biosystems Engineering
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• v.9 no.2
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• pp.97-113
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• 1984

날씨가 더운지방에 소규모(小規模) 목장(牧場)들이 먼거리를 두고 산재(散在)되어 있는 경우, 각목장(各牧場)에서 생산(生産)된 우유(牛乳)를 수집(收集)해서 처리공장(處理工場)까지 수송하는 데는 많은 어려움이 있다. 현대화(現代化)된 우유처리공장(牛乳處理工場)이나 저온저장시설이 충분(充分)하지 못한 아열대지방(亞熱帶地方)에 위치(位置)한 발전도상국에서는 우유(牛乳)를 장시간(長時間) 수집(收集)하여 먼거리를 수송하는 동안 많은 양(量)의 우유(牛乳)가 부패 손실(損失)되고 있다. 이 문제를 해결(解決)하기 위하여, 그곳 현지목장(現地牧場)에 강하게 쪼이는 태양열(太陽熱)을 이용(利用)하는 것은 대단히 바람직 하다. 에너지 절약이나, 우유(牛乳)의 부패손실(腐敗損失) 막기 위하여, 태양열(太陽熱)을 이용(利用)한 소규모우유처리기(小規模牛乳處理機)를 개발하여 현지목장(現地牧場)에서 직접(直接) 우유를 처리(處理)하여 인근주민에게 공급하는 것이 가장좋은 해결방법이라 판단하고, 그 실현가능성을 확인(確認)하기 위하여 실제로 태양열(太陽熱)우유처리기(處理機) 개발(開發)을 위한 그 모형(模型)의 회로구성(回路構成)을 고찰(考察)한 결과(結果) 다음과 같다. 1. 태양열(太陽熱) 우유처리기(牛乳處理機)의 모형(模型)은 다음 4개(個)의 회로(回路)로 구성(構成)되었다. 가. 우유(牛乳)순환 회로(回路) 나. 가열회로(加熱回路) 다. 예냉회로(豫冷回路) 라. 냉각회로(冷却回路) 2. 우유가열회로(牛乳加熱回路)는 태양열(太陽熱)을 이용(利用)하였으며 냉각회로(冷却回路)는 압축식 냉각기(冷却機)를 이용(利用)하였다. 3. 자동제어(自動制御)시스템을 장치(裝置)하여 태양강도변화(太陽强度變化)에 따른 우유처리량(牛乳處理量) 조절(調節)을 자동화(自動化)할 수 있도록 하였다.

• Journal of the Microelectronics and Packaging Society
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• v.24 no.4
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• pp.85-90
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• 2017

The $TiCl_4$ as a blocking material is adsorbed in the mesoporous $TiO_2$ electron transfer layer(ETL) of the Perovskite solar cell to prevent the direct contact between the FTO electrode and the photoactive layer(AL), and facilitate the movement of the electrons between $TiO_2:TiCl_4$ ETL and Perovskite AL to improve the photoelectric conversion efficiency(PCE). The structure of the perovskite solar cell is FTO/$TiO_2:TiCl_4$/Perovskite($CH_3NH_3PbI_3$)/spiro-OMeTAD/Ag. It was investigated that the dipping time of the $TiO_2$ into $TiCl_4$ aqueous solution affects on the photoelectric characteristics of the device. By the dipping for 30 minutes, the PCE of the perovskite solar cell with the $TiO_2:TiCl_4$ ETL was the highest 10.46%, which is 27% higher than the cell with $TiO_2$ ETL. From SEM, EDS, and XRD characterization on the $TiO_2:TiCl_4$ ETL and the perovskite AL, it was measured that the decrease of the porosity of the $TiO_2$ layer, the detection of the Cl component by the $TiCl_4$ adsorption, the cube-type morphology of perovskite AL, and shift of the $PbI_2$ peak of the perovskite AL. From these results, it was confirmed that the $TiO_2:TiCl_4$ ETL and the perovskite AL were formed.

• Journal of Korean Port Research
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• v.11 no.1
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• pp.85-99
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• 1997

The improvements of berth productivity is closely related to berth/port systems and its relationship extends to the overall pattern of port development/logistics, transport and trade. Since ports in general and berths in specific function as a bridge transferring seaborne cargoes from seaside to landside and vice versa, berth productivity improvements should be considered in terms of the total system in which the cargoes are transported from origin to destination via berths/ports. In that respect, the objective of this study is to improve berth productivity which is a vital factor in the strategic planning in port development and operation and logistics. According to a literature survey on the subject, the contents of the studies have been limited to either a macro-perspective or a micro-perspective which is only a partial solution to the problem. Hence, this limitation requires an integrated approach to find and ultimate solution, which should be considered not separately, but as a whole. The contents and scope of this study cover the improvements of berth productivity in conjunction with strategic planning in port development. efficient operation and logistics from two different viewpoints, macro- and micro-perspective. After that, a combination of these two perspectives is applied to the integrated approach due to lacking a comprehensive perspective from either macro-approach or micro-approach. In reality, a port itself is a complex and dynamic organization. Therefore, a comprehensive insight needs an integrated approach for the long-term national economic development. In this approach, the utmost importance is how to find the bottlenecks and to solve the problems effectively from the beginning stage in port development. In conclusion, derived from the macro- and micro-perspective. the attempt to establish an integrated approach is the merit of this study, which is required as a comprehensive measure since none of the two can be a solution independently. In terms of reinforcing this study, it needs further empirical research due to the restriction of the theoretical method of this paper. Consequently, the reinforced research will be able to enhance the integrated approach on the basis of the conceptual perspective.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.1
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• pp.119-131
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• 2021

This study quantitatively derived the direct socio-economic effects of the Gyeongbu Expressway, which opened in 1970, and suggested a methodological approach for more reliable results. The scenario was set when the Gyeongbu Expressway was not constructed in 1970, the opening of the Gyeongbu Expressway was delayed by 10 years, and the toll road between Seoul and Daejeon, or between Seoul and Gangneung was opened instead of the Gyeongbu Expressway as suggested by the World Bank. In addition, direct benefits were estimated by calculating and comparing the current vehicle operating costs, travel time costs, traffic accident costs, and environmental pollution costs. As a result, it was estimated that about 351 trillion won in direct benefits occurred, and it can be seen that the promotion of the construction project of the Gyeongbu Expressway at that time had a huge impact on South Korea's social economy.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.174.2-174.2
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• 2011

최근 유가상승과 석유, 천연가스의 가채 매장량의 한계등과 함께 온실가스에 의한 지구온난화 방지를 위하여 미국, 유럽국가 및 캐나다 등에서는 바이오매스를 이용한 에너지 회수 기술개발에 많은 관심과 연구를 수행하고 있다. 바이오 매스는 에너지 밀도 대비 존재하는 지역이 광범위하여 발생, 수집, 수송에 따른 비용이 많이 소요되는 특성이 있어 산지에서 직접처리하거나 수집하여 대규모처리등과 같이 여러 가지 현장상황에 따라 적정한 플랜트 운용의 유연성을 갖추고 있어야 한다. 일반적으로 바이오매스로부터 중소형으로 분산형 발전이나 수소제조를 위해서는 직접 연소법 보다는 가스화 방식을 이용하고 있는데, 연소에 의해 열을 생산하여 전기를 생산하는 방식은 스팀터빈을 이용하는 것이며, 스팀터빈은 소형 운용이 어렵기 때문이다. 본 연구에서는 폐목재로부터 합성가스제조를 위하여 5톤/일 규모 가스화기를 제작하였으며, 타르 및 수트와 같은 미반응 물질을 제거할 수 있는 집진, 세정장치를 설계 및 제작하였다. 또한 합성가스에 함유된 현열로부터 열회수를 위하여 열교환기를 설치하였으며, 정제된 합성가스를 이용하는 가스엔진을 통하여 열병합 발전시스템 연계운전을 수행하였다. 운전 실험을 폐목재 가스화 3톤/일 규모로 수행하였으며, 평균 1,500kcal/$Nm^3$의 발열량을 갖는 합성가스를 생성시킬 수 있었다. 사이클론, 스크러버 및 기수분리 장치를 이용하여 정제된 합성가스는 합성가스 엔진을 통하여 72kW 이상의 전력생산이 가능하였다. 열교환기를 통하여 평균 15,000kcal/h의 배열 회수가 가능하였으며, 바이오매스 가스화 합성가스를 이용한 열병합 발전이 가능함을 입증하였다.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.32.4-33
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• 2016

활동성은하핵(AGN)의 거대 블랙홀 주변에 존재하는 플라스마 디스크의 구조나 물리적인 상태를 관측으로 직접 찾는 것은 AGN 중심부분에서의 제트 형성, 방출과정이나 에너지 수송과정을 조사하기 위해 중요한다. 지금껏 주로 센치미터파장 영역의 다주파 VLBI 관측으로 우리은하에서 가까운 AGN 속에 존재하는 10 pc 정도의 플라스마 디스크가 발견되어 있다만, AGN의 활동성을 정하고 있는 1 pc 이하의 스케일에서의 디스크 구조를 직접 관측한 결과는 아직 없다. 우리는 2015년8월부터 KVN 및 KVN과 일본 VERA로 구성되는 한일공동 VLBI 관측망(KaVA)을 이용해서 전파 은하 3C 84(z = 0.0176, 1 mas = 0.36 pc)의 밀리미터파장 모니터링을 진행하고 있다. KVN과 KaVA를 이용하면 1 pc 이하의 스케일로 3C 84의 중심구조를 고감도에서 분해할 수 있다. 이번 발표에서는 KVN 및 KaVA로 거의 동시에 실시한 관측결과를 중심으로 보고한다. 관측은 2016년2월22일(KaVA 43 GHz) 및 23일(KVN 86 GHz)에 실시되었다. 양 주파수의 이미지에서 종래의 센치미터 ~ 밀리미터파장 VLBI관측으로도 검출되어 있는 중심핵(C1) 및 남쪽에 약 3 mas 떨어져서 위치하는 로브(C3) 성분 뿐만 아니라 C1으로부터 북쪽에 약 2.5 mas 떨어져서 위치하는 새로운 성분(N1)을 검출하였다. N1의 검출 수준은 43, 86 GHz 모두 $6{\sigma}$이며, 양 주파수 사이에서 광학적으로 두꺼운 스펙트럼을 가지고 있다. 과거의 관측으로 측정된 C3의 겉보기 속도는 빛의 속도의 약 23%이며, 남북 로브의 구조와 운동의 대칭을 가정하면 N1이 도플러 분사출 효과 때문에 어두워지고 있는 가능성은 낮다. 따라서 C3에 대응하는 북쪽 N1로브로부터의 복사가 블랙홀 주변의 플라스마 디스크로 인해 저주파수에서 강한 흡수를 받고 있는 결과고 생각된다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.6
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• pp.235-241
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• 2010

The static electricity generated by friction of two objects is called frictional electricity. The main cause of troubles in electronic components for military and civil use as well as in military radar appliances is found mostly in parts like LSI memories, particularly when they lose information of function momentarily while in operation, which usually leads to a fatal cause of troubles in the equipment. Troubles occur if electric noise is caused by the spark effected from discharge of static electricity from the equipment that is used nearby.