Although the Ti–6Al–4V alloy has been used in the aircraft industry owing to its excellent mechanical properties and low density, the low formability of the alloy hinders broadening its applications. Recently, laser-powder bed fusion (L-PBF) has become a novel process for overcoming the limitations of the alloy (i.e., low formability), owing to the high degree of design freedom for the geometry of products having outstanding performance used in hightech applications. In this study, to investigate the effect of bulk shape on the microstructure and mechanical properties of L-PBFed Ti-6Al-4V alloys, two types of samples are fabricated using L-PBF: thick and thin samples. The thick sample exhibits lower strength and higher ductility than the thin sample owing to the larger grain size and lower residual dislocation density of the thick sample because of the heat input during the L-PBF process.

Because magnets fabricated using Nd-Fe-B exhibit excellent magnetic properties, this novel material is used in various high-tech industries. However, because of the brittleness and low formability of Nd-Fe-B magnets, the design freedom of shapes for improving the performance is limited based on conventional tooling and postprocessing. Laserpowder bed fusion (L-PBF), the most famous additive manufacturing (AM) technique, has recently emerged as a novel process for producing geometrically complex shapes of Nd-Fe-B parts owing to its high precision and good spatial resolution. However, because of the repeated thermal shock applied to the materials during L-PBF, it is difficult to fabricate a dense Nd-Fe-B magnet. In this study, a high-density (>96%) Nd-Fe-B magnet is successfully fabricated by minimizing the thermal residual stress caused by substrate heating during L-PBF.

본 논문은 쿠데타 이후 군부의 정치 퇴진을 경험한 국가를 대상으로 한 사례 연구에서 발견된 다양한 퇴진 조건들을 토대로 하여, 미얀마에 서 군부의 정치 퇴진이 쉽게 이뤄지지 않는 상황을 규명한다. 이를 위해 파이너(S. E. Finer)가 군부 성향과 사회적 조건, 동기와 필요조건 간 상 호작용을 2대2 대응 관계로 구성하여 제시한 군부 퇴진 조건을 적용하였 다. 주요 결론은 군부의 민간 우위에 대한 확신, 군부 단결에 대한 위협, 통치에 대한 자신감 부족, 퇴진에 대한 내부 합의, 내부 도전, 외부 요 인, 권력을 넘겨줄 민간단체의 등장 등 주요 퇴진 조건과 미얀마 상황이 부합되지 않음으로써 군부의 정치 퇴진이 순조롭지 않고, 군부정권이 유 지될 수밖에 없는 현상을 야기한다는 것이다. 다만, 유엔 안보리 결의, 시 민불복종운동(CDM: Civil Disobedience Movement), 국민통합정부(NUG: National Unity Government) 구성 및 국민방위대(PDF: People’s Defence Force)의 투쟁 활동은 장기적으로 군부의 정치 퇴진에 영향을 미칠 것으 로 예상된다.

본 연구는 대학의 피부미용 전공교육에서 문제중심학습(PBL) 적용에 따른 학습효과를 알아보 고, 피부미용 교육경쟁력을 강화할 수 있는 교수·학습방법 개발을 위한 기초자료 제공을 목적으로 하였다. 이에 본 연구는 H대학교에 개설된 피부미용 전공 교과목인 “동양요법” 수강 학생 15명을 대상으로 PBL 수업을 적용하여 실증적 교육효과 분석을 실시하였다. 그 결과 PBL 수업을 참여한 후 학습자들의 문제해 결 능력과 협력적 자기효능감의 평균값이 상승하여 유의미한 차이를 보였으며, 이에 따라 PBL 교수학습법 의 효과성이 확인되어 피부미용 교육 현장에서 학습자들의 문제해결 능력과 협력적 자기효능감 상승을 위 한 효과적인 교수학습법으로 제안하는 바이다.

본 연구는『짜라까 상히따』를 통해서 인간의 신체를 재정립해 보는 것이며, 인간 구성과 원리를 통 해서 좀 더 신체에 다가가 보는 것이 필요하기 때문이다. 본 연구의 목적은 인간 구성요소의 특징들 을 살펴보고, 신체와 영혼에 대한 구분과 인간과 우주 사이에 불가분의 관계를 고찰하여 아유르베다 를 공부하는 사람들에게 기초자료를 제공하고 하는 것이다. 짜라까 상히따에서 인간은 몸, 마음, 영혼 이라 하고, 물질적 요소의 구성으로 아홉가지를 기술하였다. 신체론에서 인간구성은 허공, 바람, 불, 물, 땅과 뿌루샤이다. 이 여섯가지 구성은 다시 24가지 요소로 세분화 되며, 24원리로 설명하고 있다. 24요소에서 감각기관과 대상들은 신체에, 아항까라와 붓디는 영혼에 포함된다. 24원리에서 지각하는 주체는 영혼이지만 영혼의 지각적 양상은 마음과 몸이 결합할 때만 스스로 나타난다. 이것이『짜라까 상히따』에서 신체 구성에 대해 구체적인 설명이 필요한 이유이다.

Barnea manilensis is a bivalve which bores soft rocks, such as, limestone or mudstone in the low intertidal zone. They make burrows which have narrow entrances and wide interiors and live in these burrows for a lifetime. In this study, the morphology and the microstructure of the valve of rock-boring clam B. manilensis were observed using a stereoscopic microscope and FE-SEM, respectively. The chemical composition of specific part of the valve was assessed by energy dispersive X-ray spectroscopy (EDS) analysis. 3D modeling and structural dynamic analysis were used to simulate the boring behavior of B. manilensis. Microscopy results showed that the valve was asymmetric with plow-like spikes which were located on the anterior surface of the valve and were distributed in a specific direction. The anterior parts of the valve were thicker than the posterior parts. EDS results indicated that the valve mainly consisted of calcium carbonate, while metal elements, such as, Al, Si, Mn, Fe, and Mg were detected on the outer surface of the anterior spikes. It was assumed that the metal elements increased the strength of the valve, thus helping the B. manilensis to bore sediment. The simulation showed that spikes located on the anterior part of the valve received a load at all angles. It was suggested that the anterior part of the shell received the load while drilling rocks. The boring mechanism using the amorphous valve of B. manilensis is expected to be used as basic data to devise an efficient drilling mechanism.

In this study, as the proportion of aged pipelines increases rapidly, in the event of an accident caused by corrosion and structural deterioration of metal pipes, appropriate overlay welding is applied in the field to partially repair it. The size of the base steel plate and the selection of a stable welding method were evaluated, and possible problems caused by the overlay welding were identified, and improvement measures were proposed. For the test, a new steel pipe coated with epoxy lining on the inner surface and polyethylene on the outer surface was subjected to a tensile test by processing the repaired specimen through overlay welding with a steel plate after artificial cracking, and structural safety was evaluated after repair. Furthermore, the influences of the size of the throat and the size of the steel plate were analyzed. As a result of the tensile test by dividing the repaired steel plate overlay into a constraint and non-constraint conditions, the tensile load was concentrated in the welded part and damage occurred in the welded part. It was found that the maximum load leading to breakage increases as the size of the welding throat increases. In addition, it was found that the resistance to load increased slightly as the size of the overlaid steel plate increased, but the effect was not significant, confirming the need for repair in consideration of the site conditions. As a result of evaluating the damage to the coating material on the back side of the welding, it was confirmed that the coating material on the opposite side of the welding burned black(epoxy) or was greatly deformed by heat(polyethylene). Therefore, it is necessary to secure structural stability through repainting, etc. in order to prevent damage to the coating material on the opposite side during overlay welding.

The management of algal bloom is essential for the proper management of water supply systems and to maintain the safety of drinking water. Chlorophyll-a(Chl-a) is a commonly used indicator to represent the algal concentration. In recent years, advanced machine learning models have been increasingly used to predict Chl-a in freshwater systems. Machine learning models show good performance in various fields, while the process of model development requires considerable labor and time by experts. Automated machine learning(auto ML) is an emerging field of machine learning study. Auto ML is used to develop machine learning models while minimizing the time and labor required in the model development process. This study developed an auto ML to predict Chl-a using auto sklearn, one of most widely used open source auto ML algorithms. The model performance was compared with other two popular ensemble machine learning models, random forest(RF) and XGBoost(XGB). The model performance was evaluated using three indices, root mean squared error, root mean squared error-observation standard deviation ratio(RSR) and Nash-Sutcliffe coefficient of efficiency. The RSR of auto ML, RF, and XGB were 0.659, 0.684 and 0.638, respectively. The results shows that auto ML outperforms RF, and XGB shows better prediction performance than auto ML, while the differences between model performances were not significant. Shapley value analysis, an explainable machine learning algorithm, was used to provide quantitative interpretation about the model prediction of auto ML developed in this study. The results of this study present the possible applicability of auto ML for the prediction of water quality.

Incheon is an area where complaints about odors occur frequently and there are many sources of odor emission. In this study, we used a real-time monitoring device to measure the odorous concentration near the areas where there are complaints about odors. The measurements were carried out for the three areas (G, C, S) that are located around emissions sources. G is situated in an industrial complex that has a reputation for being one of the most foul smelling regions of Incheon. A petroleum refining plant and storage facility are located around C. S is a residential area nearby an industrial site. The concentration of major designated odor substances in the G and S areas satisfied the site boundary emission standards. With regard to the characteristics of odor substances by region, although the C area region had the highest odor intensity among the three regions due to the odor intensity near the oil storage facility areas G and S were similar in terms of odor intensity. In the region of the G area, the odor intensity was slightly higher at the northern side of t he industrial complex. In terms of the odor intensity of the designated odor substances, trimethyl amine was the strongest, followed by hydrogen sulfide. The real time monitoring system was necessary to analyze the changing trends of odor substances and for the determination of major odor sources. This study was conducted to identify the material causes of odors in areas of Incheon where there are frequent complaints about major odors.

The annual number of odor complaints increased about 10 times over 14 years from 4,302 in 2005 to 40,854 in 2019, in Korea. Especially, livestock facilities account for more than 50% of the odor complaints and the swine farms account for the most odor complaints among livestock. It is therefore necessary to manage swine farms as the major odor emission source. In this study, a real-time odor monitoring system equipped with PTR-TOF-MS (proton transfer reaction time-of-flight mass spectrometric) was used to measure the odorous substances in two swine farms. Odorous substances emitted from outlets were sampled and measured at the two types of swine farms. In addition, the boundary spots were designated as measurement points. As a result, the rankings of the odorous substances in order, from highest to lowest, were ammonia, acetaldehyde, methyl mercaptan, fatty acids, etc. and the level of odor intensity was 0.8-4.4 at the outlet of the swine farms. The concentration at the boundary decreased between 1/100 ~ 1/10000 compared to the concentration emitted from outlets. Base on the results of evaluating odor activity values, Skatole and p-Cresol were estimated as major odor substances in swine farms.

본 연구에서는 해상가두리 양식장에서 북방전복과 둥근전복속 교잡종(왕전복♀*둥근전복♂)의 생물지표를 분석하여 교잡육종의 결과를 평가하고자 하였다. 생존율은 북방전복과 유사하였 으나, 성장(각장)은 교잡종에서 약 10% 빠른 것으로 분석되었다. 패각의 호흡공 기형율은 교잡 종이 북방전복보다 약 6% 낮았으며, 패각 함몰 및 부식율은 교잡종이 약 15% 낮았다. 생화학 적 조성에서는 조단백질의 경우 교잡종에서 약 3.1% 높았으며, 이를 제외한 나머지에서 유사 한 값을 나타냈다. 소화, 흡수 및 해독기능을 수행하는 간췌장의 조직학적 평가에서는 교잡종 에서 좋은 결과를 보였다. 이러한 결과로 보아 둥근전복속 교잡종은 추후 양식 환경에 접목 하였을 때 높은 양식 생산력을 가질 것으로 판단된다.

본 실험에서는 무전해 도금을 통하여 Pd 및 Pd-Cu 분리막을 제조하여 수소 투과 성능을 분석하였다. 분리막의 지 지체는 α-Al2O3 세라믹 중공사를 사용하였다. Pd-Cu 분리막은 무전해 도금을 실시하였고 Pd-Cu 합금을 만들기 위하여 수소 분위기에서 500°C, 18 h 동안의 열처리 과정을 거쳤다. 그 후, Pd-Cu 분리막은 EDS (Energy Dispersive X-ray Spectroscopy), XRD (X-ray Diffraction) 분석을 통해 합금이 형성된 것을 확인하였다. Pd 및 Pd-Cu 도금층의 두께는 SEM (Scanning Electron Microscope) 분석을 통해 각각 약 3.21, 3.72 μm으로 측정되었다. 수소 투과 성능은 수소 단일 가스, 혼합가스(H2, N2)에서 350~450°C, 1~4 bar의 범위에서 수소 투과 실험을 진행하였다. 수소 단일 가스에서 Pd 및 Pd-Cu 분리막은 450°C, 4 bar에서 최대 54.42, 67.17 ml/cm2⋅min의 flux를 가지며, 혼합가스에서는 450°C, 4 bar의 조건일 때, 각각 1308, 453의 separation factor가 나오는 것을 확인하였다.

본 연구는 현재까지 중앙정부를 제외한 행위자들-특히 한국의 지방자 치단체와 기업, 그리고 양국에 존재하는 거주민 커뮤니티-의 한국과 인 도네시아 사이의 관계 형성에 관한 여러 활동을 분석 및 평가하고, 이를 바탕으로 보다 지속 가능하고 미래지향적인 양국관계 구축을 위한 정책 과제를 제시한다. 이를 위해 연구에서는 먼저 국가중심적이면서 경제력 과 군사력에 바탕을 둔 이른바 “하드파워”적 전통외교는 민간행위자들의 외교적 역량을 과소평가한다는 한계를 지적하면서, 한국과 같은 중견국 에게는 다양한 행위자들이 참여하는 “소프트파워”적인 공공외교가 필요 함을 주장한다. 또한, 한국과 인도네시아 사이의 관계 형성의 관점에서 공공외교의 주요 행위자들인 지방자치단체, 거주민 커뮤니티, 그리고 기 업의 역할을 다양한 자료들을 이용하여 평가한다. 마지막으로 하드파워 와 소프트파워가 결합한 이른바 “스마트파워”에 바탕을 둔 한국과 인도 네시아의 관계발전을 위해서 (1) 지자체 공공외교의 지역적 다양화와 내 용적 심화 (2) 양국 거주민 커뮤니티를 민간외교의 교두보로 발전시키기 위한 지원 (3) 한국기업의 환경, 사회, 지배구조(ESG)경영을 통한 인도네 시아 지역사회 공헌을 제안한다.