본 연구에서는 2011년부터 2024년까지 새만금 지역의 4개 주요 지점(만경강, 동진강, 신시갑문, 가력갑문)에서 수집된 수질 자료 를 이용하여 용존산소(DO)와 총유기탄소(TOC) 예측을 위한 XGBoost 기반 모델을 구축하고, SHAP 분석을 통해 변수별 상대적 설명력을 평가하였다. 모델은 DO에서 R² 0.89–0.95, TOC에서 0.88–0.95의 높은 예측 성능과 낮은 평균제곱오차(MSE)를 보여, 예측의 신뢰성을 확 인하였다. SHAP 분석 결과, 하천 지점에서는 pH와 수온이 DO 예측에서 가장 높은 설명력을 보였고, 염분의 영향은 미미하여 외해수 유입 이 제한적임을 나타냈다. 반면, 기수 지점에서는 수온이 DO 예측의 주요 요인으로, 염분은 보조 요인으로 작용하였다. 연도별 분석에서는 하천 지점에서 pH의 기여도가 2016년 이후 감소하고 수온의 비중이 2019년 이후 다소 높아지는 경향이 일부 나타났으나, 전체적으로는 명 확한 증가·감소 추세가 확인되지 않았다. TOC 예측에서는 하천 지점에서 COD와 chlorophyll-a가, 기수 지점에서는 chlorophyll-a와 염분이 상 대적으로 중요한 설명 변수로 확인되었다. COD의 기여도는 2017–2018년에 낮았다가 2019–2021년에 높아진 후 최근 다시 감소하는 등 일부 연도에서 변동이 나타났으나, 뚜렷한 장기 경향은 관찰되지 않았다. 이러한 결과는 연도별로 변수의 상대적 설명력에 세부적인 변동 은 존재하지만 전체적으로 일관된 추세는 아직 확립되지 않았음을 보여준다. 이처럼 연도별 변동성과 불확실성이 공존하는 환경에서, XGBoost와 SHAP을 결합한 접근법은 각 변수의 상대적 중요도와 시기별 변화를 정량적으로 평가할 수 있는 유용한 분석 틀을 제공한다.

This study explored the process-structure-property (PSP) relationships in Ti-6Al-4V alloys fabricated through direct energy deposition (DED) additive manufacturing. A systematic investigation was conducted to clarify how process variables—specifically, manipulating the cooling rate and energy input by adjusting the laser power and scan speed during the DED process—influenced the phase fractions, pore structures, and the resultant mechanical properties of the samples under various processing conditions. Significant links were found between the controlled process parameters and the structural and mechanical characteristics of the produced alloys. The findings of this research provide foundational knowledge that will drive the development of more effective and precise control strategies in additive manufacturing, thereby improving the performance and reliability of produced materials. This, in turn, promises to make significant contributions to both the advancement of additive manufacturing technologies and their applications in critical sectors.

세형동검문화의 청동제 목공구로는 동부와 동착이 있다. 동착은 단순하지만 동부는 선형동부와 유견 동부, 장방형동부, 주머니형동부로 다양하다. 이 중 합인인 주머니형동부를 제외한 나머지는 모두 편인 이다. 필자들은 민족지 자료를 검토하는 과정에서 1960년대까지 신석기시대 농경민의 삶을 살고 있었 던 뉴기니의 두굼 다니가 돌도끼는 나무를 쪼개는 데 사용했고, 자귀는 나무를 베고 다듬는 데 사용한 사실을 확인하였다. 이에 따라 필자들은 장방형동부를 도끼와 자귀로 착장해서 나무 베기 실험을 진행 하였는데, 자귀로 사용했을 때 훨씬 더 효과적이라는 사실을 확인하였다. 이러한 양상은 두굼 다니의 사례, 그리고 돌도끼와 돌자귀로 나무 베기를 진행한 실험고고학적인 연구 결과와도 상통한다. 즉, 장방형동부는 나무를 벨 수도 있고 다듬을 수도 있는 자귀여서 長方形銅錛이라는 명칭이 더 적합하다. 나아가 세형동검문화의 동부들은 합인인 주머니형동부를 제외한 나머지는 모두 자귀여서 有肩銅錛, 扇形 銅錛으로 부르는 것이 타당하다. 한국 고고학계에서는 목공구의 명칭을 총칭해서“斧”로 쓰거나“斧”와“鑿”으로 이원해서 쓰는 경 향이 강하다. 하지만 이러한 목공구 명칭은 현대 대목장의 연장인 도끼, 자귀, 끌이나 18세기에 편찬된 『才物譜』의 斧(독긔), 錛子(자귀), 鑿( )이라는 명칭과 달라서 대중들의 인식과 괴리되어 있다. 그 래서 한국 고고학계에서도 목공구의 명칭을 도끼(斧), 자귀(錛), 끌(鑿)과 같이 전통적이면서도 현대적 이어서 대중들이 이해할 수 있는 명칭으로 수정해야 할 것이다.

The present study was conducted to examine the effect of recombinant bovine somatotropin(γBST), which was administered to cow to promote milk production, on bST levels in milk. Fourteen cows were divided into two groups: 1) control cows received neither γbST nor vehicle, 2) treated cows were administered twice at two-week interval with 500 mg γbST each cow by subcutaneous injection. Milk samples were taken on day 0 (prior to injection), day 7 (7 days after 1st injection), day 21 (7 days after 2nd injection) and day 35 (21 days after 2nd injection). Milk bST concentration was measured by the radioimmunoassay method. There was no statistical difference(p$lt;0.05) in milk bST levels between two groups showing bST levels in the range of 1.8 ng/ml to 3.1 ng/ml. That is, γbST administration did not increase bST levels in milk.

The study was performed to explore the molecular changes in the vegetative stage (3-and 5-leaf) of sorghum under waterlogging stress. A total of 74 differentially expressed protein spots were analyzed using LTQ-FT-ICR MS. Among them, 12 proteins were up-regulated and 3 proteins were down-regulated. Mass spectrometry (MS) results showed that about 50% of the proteins involved in various metabolic processes. The level of protein expression of malate dehydrogenase and glyceraldehyde-3-phosphate dehydrogenase related to carbohydrate metabolic process increased in both 3 and 5-leaf stage under waterlogging stress. These proteins are known to function as antistress agents against waterlogging stress. The expression of oxygen-evolving enhancer protein 1 protein related to photosynthesis was slightly increased in the treated group than in the control group, however the expression level was increased in the 5-leaf stage compared to the 3-leaf stage. Probable phospholipid hydroperoxide glutathione peroxidase protein and superoxide dismutase protein related to response to oxidative stress showed the highest expression level in 5-leaf stage treatment. This suggests that the production of reactive oxygen species by the waterlogging stress was the most abundant in the 5-leaf treatment group, and the expression of the antioxidant defense protein was increased.

The growth of the Waste-to-Energy (WTE) industry is attracting attention as a powerful means of reducing greenhouse gas emissions; the Korean government is supporting various efforts such as increasing R&D investment. Despite the importance of the WTE industry, the analysis of R&D efficiency remains insufficient. This study analyzes the R&D efficiency of the Korean WTE industry and its determinants. After R&D activities are separated into input and output, R&D efficiency is analyzed with regard to whether R&D input contributes to increased R&D output using multiple regression and logistic regression methodologies based on the survey of Korean WTE firms. In the results of analysis, the introduction of new products and services was positively affected by R&D manpower and education-training. In addition, the redesign of products and processes was positively affected by R&D expenditure, R&D manpower, education-training, and the reward system. The policy implication is that education and training for R&D manpower should be provided to improve R&D efficiency, and there should be investment in basic and applied research and development research should be expanded to gain global compETitiveness.

Background:This study was aimed to determine the optimal vine induction method for growing of Korean schisandra (Schisandra chinensis), by comparing plant growth and fruit yields between plants grown with either fence-type (U-type) or A-type induction.Methods and Results:Plants were transplanted on August 17, 2014, and the plant height, stem node number and weight were measured every two weeks, six times from June 17, 2017. The plant height, stem node number, and leaf length and width were higher with the A-type than with the U-type induction, by approximately 37.0%, 49.1%, 27.6%, and 12.7%, respectively. Although there was no significant difference between the photosynthesis rates of plants grown with the two vine induction method, the leaf area and leaf number per plant were higher in the plants grown with the A-type than the U-type, by approximately 23.7% and 46.0%, respectively. The number of green-color pixels, in a defined area of digital camera images of creeper leaves from the inducted vines, was significantly higher in the plants grown with the A-type than the U-type. The number of fruit clusters per plant was approximately 26 and 36, under the U-type and A-type, respectively. A two fold higher total fruit weight per plant was observed in the plants grown under the A-type (250 g/plant) than the U-type (120 g/plant).Conclusions:The A-type vine induction method is optimal for cultivation of Korean schisandra.