The Gymnocalycium mihanovichii has been an important export item of Korean flower industry for a long time. Although there is a high demand for grafted cactus from overseas, its production for export is limited. In this study, the growth and marketable yield characteristics of Gymnocalycium mihanovichii ‘I-Hong’ were compared between soil culture and ebb-and-flow hydroponic system with single- or double-tier bench. As a result, hydroponic methods with single-tier bench resulted in higher fresh weight and glove diameter compared to other cultivation methods. In the ebb-and-flow hydroponic system, hydroponic system with double-tier bench of grafted cactus traits has a lower growth rate than other cultivations. However, the hydroponic system with double-tier bench of grafted cactus significantly increased the yield. In conclusion, the yield from hydroponic system with double-tier bench was better than soil cultivation method. Although there were some differences in color depending on the cultivation method, it was considered that there was no difference in appearance of Gymnocalycium mihanovichii ‘I-Hong’. Our results suggest the cultivation methods to overcome production constraints, expand their exports, and improve the value-added characteristics of grafted cactus.

High-temperature and high-pressure post-processing applied to sintered thermoelectric materials can create nanoscale defects, thereby enhancing their thermoelectric performance. Here, we investigate the effect of hot isostatic pressing (HIP) as a post-processing treatment on the thermoelectric properties of p-type Bi0.5Sb1.5Te3.0 compounds sintered via spark plasma sintering. The sample post-processed via HIP maintains its electronic transport properties despite the reduced microstructural texturing. Moreover, lattice thermal conductivity is significantly reduced owing to activated phonon scattering, which can be attributed to the nanoscale defects created during HIP, resulting in an ~18% increase in peak zT value, which reaches ~1.43 at 100oC. This study validates that HIP enhances the thermoelectric performance by controlling the thermal transport without having any detrimental effects on the electronic transport properties of thermoelectric materials.

This study was conducted to apply with an air duct for the cooling and a utilizing cultivating method that uses the fruiting node and the defoliation to the high-temperature vertical and hydroponic cultivation of the oriental melon. The lower fruiting node (LF) was to remove all third vines generated from 5 nodes of a secondary vine. The higher fruiting node (HF) was fruiting on the third vine generated from a first node of the third vine. The direction of the stem string; upward (UW), downward (DW). Four treatment conditions were applied with the LF-UW, LF-DW, HF-UW (control), and HF-DW. The leaf age of melon leaves was measured for photosynthesis at 3 days intervals, and the fruit characteristic was conducted on 79 fruits in each treatment. The photosynthesis rate steadily increased after leaf development, reaching 20.8 μmol CO2·m-2·s-1 on the 10 days, gradually increasing to 21.3 μmol CO2·m-2·s-1 on the 19 days, and reaching 23.4 μmol CO2·m-2·s-1 on the 32 days. After that, it lowered to 16.8 μmol CO2·m-2·s-1 on the 38 days and dropped significantly to 7.6 μmol CO2·m-2·s-1 on the 47 days. As a result of the fruit characteristics by fruiting nodes, the treatments of the fruit length was 12.6-13.4 cm, respectively, which was significant, and the fruit width was 7.9- 8.6 cm, respectively, was not significant. The soluble content ranged from 12.9 to 15.7°Brix, and the significance of all treatments, and higher than of LF-DW and HF-UW. The photosynthesis rate of melon leaves was good until 32 days after leaf development, but after that, the rate decreased. As for fruit quality, it was conformed that melons can be cultivated at the LF because the fruit enlargement and soluble content dose not decrease even when set at the LF. Results indicated that those can be used for LF and defoliation in the development of vertical and hydroponic cultivation method in high-temperature season.

수경 재배한 멜론의 생육과 수확 후 모의유통 시 품질 차이를 검토하였다. ‘루비볼춘추계’의 수경재배 된 멜론을 이용하여 저장 온도를 2℃와 5℃, 10℃, 20℃하여 모의유통 시 특성과 가용성고형물(SSC), 경도, 생체중 변화, 외관 등의 변화를 조사하였다. 멜론을 상온으로 유통하는 조건 하에서 저온저장에 따른 과실 특성을 본 연구에서 확인하였다. 멜론 저장 시 가용성고형물, 경도, 생체중, 외관이 저장온도에 따라 차이를 보였다. 가용성고형물은 멜론을 저온(2~5℃)에서 저장하여 모의유통 된 것이 상온(20℃)에서 다른 온도처리보다 높은 수준인 것으로 나타났다. 외관과 경도는 모의유통 중 저장 온도에 따른 영향이 지속적이지는 못하였지만 유통초기 저온(2~10℃) 저장이 외관 지수 및 경도 수치가 높은 경향이었다. 저장 온도에 따른 영향이 모의유통 시 계속 효과를 유지하지 못하여 국내 유통 시 이를 고려하여야 할 것이다. 본 연구 결과, 저장 온도에 따른 모의유통 중에 미치는 영향은 저장 직후 짧은 단기간에만 효과를 유지하여, 국내 유통 하에서 저장할 경우에는 바로 소비할 수 있도록 유도해야 할 것으로 생각된다.

생물환경조절학회지 31권 3호에 게재된 논문의 재료 및 방법의 양액 정보가 잘못 기재되어 있어 바로 잡습니다.

In this research, the a novel finishing machine was used for hight-precision surface of spherical ball products that have been widely used for on/off valve for hydrogen energy flowing system and in medical field such as artificial hip joint component. The spherical balls products are the workpiece that made by Co-Cr-Mo alloys with 32-mm in diameter and Sa≈ 0.30μm in surface roughness. Their surface roughness was successfully improved via the magnetic abrasive tools that controlled the magnetic field of permanent magnets. The critical input conditions were selected as rotational speed: 800rpm, gap: 3mm, tool grain size: 1-μm finishing time: 0, 3, 6, 9, 12, and 15min. The results of this research showed that under the given finishing conditions, the high surface quality in the terms of surface precision of spherical ball products are successfully achieved, in which the surface roughness is reduced from 0.30-μm to 0.04-μm within the short finishing time at 12min. Therefore, it can be concluded that a novel finishing machine is feasible to be used for improving the surface roughness of spherical ball products, resulted in high surface precision of materials.

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.

Tin-antimony sulfide nanocomposites were prepared via hydrothermal synthesis and a N2 reduction process for use as a negative electrode in a sodium ion battery. The electrochemical energy storage performance of the battery was analyzed according to the tin-antimony composition. The optimized sulfides exhibited superior charge/discharge capacity (770 mAh g-1 at a current density of 100 mA g-1) and stable lifespan characteristics (71.2 % after 200 cycles at a current density of 500 mA g-1). It exhibited a reversible characteristic, continuously participating in the charge-discharge process. The improved electrochemical energy storage performance and cycle stability was attributed to the small particle size, by controlling the composition of the tin-antimony sulfide. By optimizing the tin-antimony ratio during the synthesis process, it did not deviate from the solubility limit. Graphene oxide also acts to suppress volume expansion during reversible electrochemical reaction. Based on these results, tin-antimony sulfide is considered a promising anode material for a sodium ion battery used as a medium-to-large energy storage source.

본 연구는 의령군 남강하류 하천변의 식물상과 외래식물의 분포현황 및 관리방안을 제시하기 위해 수행하였다. 식물상조사는 3구간(Ⅰ: 장박교∼정 암교, Ⅱ구간: 정암교∼백곡교, Ⅲ구간: 백곡교∼낙동강 합류지점)으로 나누어 조사하였다. 조사지에서의 관속식물은 95과 279속 405종 1아종 38변종 7품종 451분류군이 출현하였다. 양치식물은 7과 11속 14종 1변종 15분류군, 나자식물은 5과 7속 8종 8분류군, 피자식물은 83과 261속 383종 1아종 37변종 7품종 428분류군이 출현하였다. 쌍자엽식물은 73과 200속 287종 1아종 23변종 7품종 318분류군, 단자엽식물은 10과 61속 96종 14변종 110분류군이 출현하여 피자식물이 약 95%로 가장 많은 분류군이 출현하였다. 희귀식물은 8과 8속 8종 8분류군으로 검팽나무, 낙지다리, 새박 등이 출현하였고, 한국특산식물은 2과 3속 4종 4분류군으로 은사시나무, 키버들, 능수버들, 오동나무 등이 출현하였다. 식물구계학적 특정식물은 30과 38속 37종 2변종 39분류군이 출현하였다. 일년생식물은 27분류군, 일년생식물(겨울형)은 17분류군, 지중식물은 4분류군, 반지중식물은 14분류 군, 지표식물은 3분류군으로 관목은 1분류군과 대교목 2분류군 이었다. 침입외래식물은 19과 54속 66종 2변종 68분류군으로 닭의덩굴, 소리쟁이, 큰석류풀 등이 출현하였고, 귀화율 약 15.1%, 도시화지수는 약 19.8%였다. 생태교란식물은 4과 7속 8종으로 8분류군이 출현하였다.

The overall process, from the pre-treatment of aluminum substrates to the eco-friendly neutral electroless Ni-P plating process, was observed, compared, and analysed. To remove the surface oxide layer on the aluminum substrate and aid Ni-P plating, a zincation process was carried out. After the second zincation treatment, it was confirmed that a mostly uniform Zn layer was formed and the surface oxide of aluminum was also removed. The Ni-P electroless plating films were formed on the secondary zincated aluminum substrate using electroless plating solutions of pH 4.5 and neutral pH 7.0, respectively, while changing the plating bath temperature. When a neutral pH7.0 electroless solution was used, the Ni-P plating layer was uniformly formed even at the plating bath temperature of 50 oC, and the plating speed was remarkably increased as the bath temperature was increased. On the other hand, when a pH 4.5 Ni-P electroless solution was used, a Ni-P plating film was not formed at a plating bath temperature of 50 oC, and the plating speed was very slow compared to pH 7.0, although plating speed increased with increasing bath temperature. In the P contents, the P concentration of the neutral pH 7.0 Ni-P electroless plating layer was reduced by ~ 42.3 % compared to pH 4.5. Structurally, all of the Ni-P electroless plating layers formed in the pH 4.5 solution and the neutral (pH 7.0) solution had an amorphous crystal structure, as a Ni-P compound, regardless of the plating bath temperature.

반추위 미생물체 단백질의 아미노산 조성이 한우의 에 너지원 사료에 따라 차이가 있는지를 조사하고자 본 연구 가 수행되었다. 본 실험은 국내 한우 비육우 사육에 주로 이용되는 에너지원 사료인 옥수수(T1), 생미강(T2), 소맥 (T3), 소맥피(T4)를 이용하여 in vitro 반추위 발효실험을 진행하여 발효 24시간 후 배양액의 발효 성상, 미생물체 단백질 합성량(MPS), 미생물의 아미노산 조성 및 미생물 균총 변화를 분석하였다. 배양액의 pH는 T4가 6.02로 다 른 처리구들에 비해서 가장 높았으며, T1은 4.84로 가장 낮았다(p<0.05). Total VFA 농도는 T2가 96.80mM로 다른 처리구들에 비해서 가장 높았고, T1이 53.35mM로 가장 낮았다(p<0.05). 미생물체 단백질 합성량은 T3가 222.50g/L로 다른 처리구들에 비해서 높았으며(p<0.05), T1과 T4는 유의적인 차이는 없었지만 T1이 가장 낮았다. DGGE band 분석결과 모든 처리구는 57.5% 이하의 유사도를 나타내었으며, 급여되는 사료에 따라서 미생물 군집 이 다르게 나타났다. 미생물 내 총 아미노산 함량은 T3와 T4가 다른 처리구보다 높았다(p<0.05). 미생물의 아미노산 조성 중 대부분의 필수 아미노산은 T4가 다른 처리구들에 비해서 낮았다. 하지만 methionine은 다른 필수 아미노산 과 다르게 T4에서 가장 높았다(p<0.05). 곡류 사료 위주의 급여 시 결핍되기 쉬운 lysine은 모든 처리구에서 미생물 의 아미노산 조성이 8.05~8.98%의 범위에 있었다. 따라서, 본 연구에서 반추 가축 급여 에너지 사료원에 따른 반추 위 내 미생물 발효특성과 미생물 군집의 차이가 미생물의 아미노산 조성을 변화시킨다는 것을 확인하였다.

As earthquakes have increased in Korea recently, people are paying attention to the seismic performance of buildings built in the past. Many school buildings in Korea were built based on standard drawings before the seismic design was applied. However, since school buildings are often designated as emergency evacuation facilities in case of disasters such as earthquakes, seismic evaluation and retrofit must be done quickly. This study investigated the failure modes among structural components (beams, columns, and joints), focusing on 1980s standard drawings for school buildings. The effects of column axial force, partial masonry infills, and different material strengths for concrete and rebar were considered for detailed evaluation. As a result, most of the joints were found to be the weakest among structural components. Column axial forces tended to make the joints more vulnerable, and partial masonry infills increased the possibility of joint failure and shear failure in columns.

In order to manufacture a mask to prepare for infectious diseases such as COVID-19 and yellow dust, it is manufactured through the process of input, fusion, cutting, band attachment, defect inspection, and packaging. Domestic mask producers introduced Chinese facilities to keep up with explosive demand due to the rapid spread of COVID-19 in 2020, but serious problems arise in durability. Therefore, domestic processing and tooling companies have developed and supplied molds, but since supply is not smooth compared to demand, research on the development of mask molds with durability reliability is urgently needed to supply masks stably. This technology development aims to supply a mask with excellent quality to a market by applying dots capable of welding and re-painting to a mold for cutting applied to a mask manufacturing process and developing dots optimized for paper angles.

The prediction of algal bloom is an important field of study in algal bloom management, and chlorophyll-a concentration(Chl-a) is commonly used to represent the status of algal bloom. In, recent years advanced machine learning algorithms are increasingly used for the prediction of algal bloom. In this study, XGBoost(XGB), an ensemble machine learning algorithm, was used to develop a model to predict Chl-a in a reservoir. The daily observation of water quality data and climate data was used for the training and testing of the model. In the first step of the study, the input variables were clustered into two groups(low and high value groups) based on the observed value of water temperature(TEMP), total organic carbon concentration(TOC), total nitrogen concentration(TN) and total phosphorus concentration(TP). For each of the four water quality items, two XGB models were developed using only the data in each clustered group(Model 1). The results were compared to the prediction of an XGB model developed by using the entire data before clustering(Model 2). The model performance was evaluated using three indices including root mean squared error-observation standard deviation ratio(RSR). The model performance was improved using Model 1 for TEMP, TN, TP as the RSR of each model was 0.503, 0.477 and 0.493, respectively, while the RSR of Model 2 was 0.521. On the other hand, Model 2 shows better performance than Model 1 for TOC, where the RSR was 0.532. Explainable artificial intelligence(XAI) is an ongoing field of research in machine learning study. Shapley value analysis, a novel XAI algorithm, was also used for the quantitative interpretation of the XGB model performance developed in this study.