본 논문에서는 반도체 특성의 단일벽 탄소나노튜브(semi-SWNTs)와 페로브스카이트(perovskite) 양자 점을 혼합하여 SWNT의 높은 전하 이동 특성과 양자점의 고효율 광전 특성을 동시에 가지는 용액공정 가 능한 기반 고성능 광센서를 개발하기 위한 연구를 수행하였다. 직경이 작은 SWNT를 공액 구조 고분자 반도체를 이용해 선택적으로 분리/분산하는 방법으로 제조하여 포토트랜지스터의 반도체 채널 층으로 활 용하고, 가시광 빛에 높은 흡광도를 가지는 양자점을 다양한 조성과 구조를 가지는 광활성층으로 제조하 여 그 특성을 비교 분석하였다. 이 결과 semi-SWNTs와 페로브스카이트 양자점 모두 단독으로 TFT에 사 용하였을 경우 우수한 트랜지스터 특성과는 별개로 광전효과가 크게 나타나지 않았으며, 두 종류 이상의 반도체 소재를 융합하여 사용할 경우 양자점에 흡수된 빛에 의해 엑시톤이 형성되고 이종 접합 계면에서 전자와 정공의 분리가 쉽게 이루어지도록 유도함으로써 낮은 광량에서도 높은 효율을 가지는 포토트랜지 스터를 개발할 수 있었다. 향후 지속적인 연구개발을 통해 고유연/저가 광 센서 제품 개발과 레이더, 이미 지 센서, 웨어러블 헬스케어 등의 다양한 분야에 하이브리드 반도체 포토트랜지스터가 응용될 수 있을 것 으로 기대한다.

This study analyzed the relationship between efficient pitchers and teams advancing to the postseason in Korean professional baseball through DEA. A total of 1,133 pitchers who threw more than one inning from the 2014 season to the 2018 season were selected for this study. For DEA analysis, input variables were selected as annual salary and inning output variables as Wins, Saves, and Holds and the number of efficient pitchers for each season was classified using the input-oriented BCC model. After that, it was divided into two groups based on joining the postseason or not, and the number of efficient pitchers was compared through a prop test. As a result of the analysis, the groups that advanced to the postseason in the rest of the season except for the 2014 and 2017 seasons had more efficient pitchers. Considering that the 2014 season recorded the highest WAR (Wins Above Replacement) at 183.56 compared to other seasons, most pitchers threw well, and in the 2017 season, they made more mistakes in pitching than in other seasons, but they performed well in batters. The results of this study have expanded the research field using efficiency analysis in professional baseball and can be used as useful data for practical research.

Due to the environmental regulations of the International Maritime Organization (IMO), the number of ships using cryogenic fuel such as LNG (liquefied natural gas) is increasing rapidly, and the demand for eco-friendly ships is expected to grow further in the future. The material of the tank for storing cryogenic fuel such as LNG is limited within the IGC Code, and available materials include 9% nickel steel, Invar (36% nickel steel), Al5083-0, STS304L, and high manganese steel. Recently, 9% nickel steel has been used as a tank in LNG fuel-powered ship projects, and it has excellent thermal/mechanical properties in cryogenic LNG environmental conditions (-163°C). In this study, it is conducted an experimental study on SAW(Submerged Arc welding), which has better welding efficiency than FCAW(Flux Cored Arc Welding), which is mainly used for 9% nickel steel materials. In addition, to verify the reliability of the welded part after the welding test, cross-sectional observation of the welded part was performed and the mechanical properties such as the tensile strength and cryogenic impact strength of the welded part were evaluated.

A porous photocatalyst concrete filter was successfully produced to remove NOx, by mixing TiO2 photocatalyst with lightweight aerated concrete. Ultra Fine Bubbles were used to form continuous pores inside the porous photocatalytic concrete filter, which was mixed via a bubble generation experiment. The optimal mixing condition was determined to be with 4% of the bubble generation agent B. NO removal specimens were prepared for various photocatalytic loading conditions, and the specimen containing 3% P-25 removed NO at a concentration of 1.03 μmol in 1 h. The NO removal rate of the porous photocatalytic concrete filter prepared in this study was 10.99%. This photocatalytic filter performance was more than 9 times the amount of NO removed by a general photocatalytic filter. The porous photocatalyst concrete filter for removing NOx developed in this study can be applied to various construction sites and the air quality can be solved by reducing NOx contributing to the formation of fine particles.

본 연구에서는 폴리술폰 분리막을 이용한 바이오가스 정제 공정으로 고선택성 소재를 이용한 2단 공정의 높은 회 수율 및 경제성과 동등한 수준의 회수율을 확보하기 위해 저온 고압의 분리막 공정을 설계하고 평가하였다. 폴리술폰 고분자 를 4성분계 도프를 이용하여 비용매 유도 상전이법으로 중공사 분리막을 제조하였다. 기체 분리용 중공사 분리막은 1.6 m2의 유효 막면적을 갖는 샘플을 제조하여 상온 및 저온에서 기체 투과 특성을 평가하였다. 제조된 기체분리막 모듈의 온도에 따 른 기체 투과 특성을 분석하기 위하여 온도별 단일 기체 투과도를 평가한 결과 이산화탄소와 메탄 투과도는 20°C에서 각각 412, 12.7 GPU이며, -20°C에서는 각각 280, 3.6 GPU로써 이상 선택도는 32.4에서 77.8로 향상되었다. 단일 기체 투과 테스 트 후 혼합 기체에 대한 분리 테스트를 진행하였으며, 모듈 1단 구성 및 2단 구성(막 면적비 1:1, 1:2, 1:3)을 통하여 투과 거 동을 살펴보았다. 1단 구성에서는 stage-cut이 상승함에 따라 메탄의 농도가 상승하지만, 반대로 회수율은 떨어지는 결과를 나 타내었다. 2단 구성 테스트에서는 메탄 농도 97% 기준에서 막 면적비 1:1보다 1:3이 메탄의 회수율이 더 높게 측정되었으며, 공급 기체의 온도가 낮을수록 메탄의 회수율이 높아짐을 확인하였고, 최종적으로 폴리술폰 2단 공정에서 메탄 농도 97%, 회 수율 97%의 결과를 달성하였다.

PURPOSES : Recently, air pollution caused by particulate matter has been worsening. Among the substances generating particulate matter, NOx is the main precursor of particulate matter and is widely distributed in areas with a high volume of traffic. TiO2 has been used as a material for removing NOx through a chemical reaction as a photocatalyst. In this context, the reduction of NOx through TiO2 concrete is proposed. However, the research on the surface deterioration on the performance of TiO2 concrete is not documented yet. Therefore, the objective of this study was to evaluate the long-term durability and NOx removal efficiency of TiO2 concrete by considering the concrete surface deterioration. METHODS : Freezing–thawing resistance test (KS F 2456) and scaling test (ASTM C 672) were performed to investigate the variation in the TiO2 penetration distribution and NOx removal efficiency of TiO2 concrete corresponding to surface deterioration. The long-term durability of TiO2 concrete was evaluated through an environmental resistance test and changes in TiO2 penetration depth and distribution characteristics. In addition, the NOx removal efficiency of TiO2 concrete was evaluated as surface deterioration occurs. RESULTS : As a result of the freeze–thawing resistance test, a relative dynamic elastic modulus of more than 80 % was detected. In addition, a TiO2 penetration depth of 0.3 mm, NOx removal efficiency of 11.2 %, and a 30 % of TiO2 surface prediction mass ratio were achieved after 300 cycles. As a result of visual observation of the scaling test, “0, no scaling” was secured. After 50 cycles of scaling test, the TiO2 penetration depth, NOx removal efficiency, and TiO2 surface prediction mass ratio were 0.3 mm, 36.3 %, and 63 %, respectively. Through the results of the environmental resistance test, the excellent long-term durability and NOx removal efficiency of TiO2 concrete were confirmed. CONCLUSIONS : As a result of the experiment, long-term durability and NOx removal efficiency of TiO2 concrete were secured. The application of TiO2 concrete can be a good alternative with long-term performance and durability.

Somatic cell nuclear transfer (SCNT) in pigs has been used as a very important tool to produce transgenic for the pharmaceutical protein, xenotransplantation, and disease model and basic research of cloned animals. However, the production efficiency of SCNT embryos is very low in pigs and miniature pigs. The type of donor cell is an important factor influencing the production efficiency of these cloned pigs. Here, we investigated the developmental efficiency of SCNT embryos to blastocysts and full term development using fetal fibroblasts (FF) and mesenchymal stem cells (MSCs) to identify a suitable cell type as donor cell. We isolated each MSCs and FF from the femoral region and fetus. Cultured donor cell was injected into matured embryos for cloning. After that, we transferred cloned embryos into surrogate mothers. In term of in vitro development, the SCNT embryos that used MSCs had significantly higher in cleavage rates than those of FF (81.5% vs. 72%) (p<0.05), but the blastocyst formation rates and apoptotic cell ratio was similar (15.1%, 6.18% vs. 20.8%, 9.32%). After embryo transferred to surrogates, nine and nineteen clone piglets were obtained from the MSCs and FF group, respectively, without significant differences in pregnancy and birth rate (50%, 40% vs. 52.3%, 45.4%) (p>0.05). Moreover, there was no significant difference in the corpus hemorrhagicum numbers of ovary, according to pregnancy, abortion, and delivery of surrogate mothers between MSCs and FF groups. Therefore, the MSCs and FF are useful donor cells for production of clone piglets through SCNT, and can be used as important basic data for improving the efficiency of production of transgenic clone pigs in the future.

월파된 파도를 이용한 파력발전시스템을 월파수류형 파력발전기 OWEC(Overtopping Wave Energy Converter)라고 한다. OWEC의 성능은 발전 시스템은 특성상 파도의 파고와 주기의 영향을 받는다. 파도는 해양에 따라 파고, 주기, 파도 방향 등의 특성이 다르고 이러 한 파도의 다양한 특성 때문에 OWEC는 안정적인 전력을 생산하기 어렵다. 따라서 각 바다의 특성에 따른 OWEC의 적절한 형상에 관한 연구가 필요하다. 본 연구에서는 SPH(Smoothed Particle Hydrodynamics) 입자법을 사용하여 OWEC의 램프 설계가 hydraulic efficiency에 미치 는 영향을 확인했다. 총 10개의 모델을 설계하였으며, 선택된 매개변수에 따라 램프의 설계 파라미터를 선택하고 사면의 형상을 변경하여 시뮬레이션을 수행하였다. 해석 결과로부터 구한 유량을 기초로 hydraulic efficiency를 산출하였다. 계산된 hydraulic efficiency를 바탕으로 각 변수가 사면의 형상에 따른 월파 성능에 미치는 영향을 확인하였다. 본 연구에서는 특정 해역에 따른 OWEC 램프의 적절한 형상에 대한 방향을 제시하였다.

지방관리 무역항은 비교적 중소형 무역항으로 지방도시의 경제력 강화 및 지역 산업 부가가치 제고를 위해 활발한 운영이 필요 하다. 또한, 선박대형화가 이루어지고 있는 국제적 흐름에서 지방관리 무역항의 효율성 증대를 위해 항만기본계획상 기존 선석규모 대비 대형선박의 접안이 필요하며, 부두 및 선박의 안전성 확보를 위해 대형선박 접안시 계류시설 확충 및 안전운용기준 마련이 필요하다. 본 연구에서는 지방관리 무역항 중 옥계항을 선정하여, 현행 2만 DWT급 부두에 5만 DWT급 선박이 계류시 시나리오에 따른 계류안전성 평 가를 수행하였다. 평가 결과, 대상 부두에 100톤급 계선주를 신설하였을 경우, 긴급이안기준은 기존 파주기 3.2초에서 풍속 27노트, 파주기 5.0초에서 풍속 22노트의 계류 한계 조건이 파주기 3.2초에서 풍속 41노트, 파주기 5.0초에서 풍속 36노트로 약 50 % 정도 증가하는 것으로 분석되었다. 본 연구 결과는 지방관리 무역항에 기존 선석규모 대비 대형선박 접안시 부두 계류시설의 안전성 강화와 안전운용기준 설정 을 위한 기초 자료로 활용될 수 있다.

In this study, we propose a standardized design method using dimensionless design factors (specific catchment area, specific storage capacity) for the catchment area and storage tank capacity for the installation of rainwater facilities under rainfall conditions in Korea. As a result of simulating the water-saving efficiency of rainwater facilities that supply toilet flushing water in 17 office buildings in the metropolitan area, it was confirmed that the specific catchment area is a major design factor affecting the water-saving efficiency. In order to achieve the annual water-saving efficiency of 30%, it was evaluated that the specific catchment area and the specific rainwater storage capacity required 0.2 or more, respectively. In addition, when looking at the monthly water-saving efficiency, it is estimated that 100% of the required water demand can be supplied for up to three months from July to September under optimal conditions. Due to the annual rainfall variation, there is a limit to using all of the collected rainwater as toilet flushing water. Consideration of temporary use for other purposes should be reflected in the design stage of the building considering the characteristics of the target building and local conditions. In the future, follow-up studies are needed for field verification of dimensionless design and efficiency evaluation based on water supply and demand.