• 한국응용곤충학회지
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• 제58권2호
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• pp.101-109
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• 2019

곤충병원선충인 Steinernema longicaudum에 공생하는 Xenorhabdus ehlersii KSY 세균은 나방류에 대한 높은 병원력을 발휘한다. 본 연구에서 이 세균의 병원력이 아이코사노이드 생합성을 억제하여 기주 곤충의 면역 저하를 유발한다는 것을 확인하였다. 그러나 이 세균의 병원력은 혈강 주입에 의해 야기된다. 섭식을 통해 이 세균을 혈강으로 전달하기 위해 곤충의 중장벽을 파괴하여 병원력을 발휘하는 Bacillus thuringiensis(Bt)와 혼합하여 처리하였다. 배추좀나방(Plutella xylostella) 유충에 대해서 X. ehlersii 세균 배양액의 혼합 처리는 Bt 살충력을 현격하게 증가시켰다. 이러한 살충효과는 또 다른 나비목 해충인 콩명나방에 대해서도 확인되었다. 제형화를 위해 X. ehlersii 세균 배양액을 동결건조하여 Bt 수화제와 혼합하였다. 이를 기반으로 간이 포장실험을 수행하였다. Bt 단독으로 처리한 결과 약 80%의 방제 효과를 보인 반면 X. ehlersii 혼합제는 95% 이상의 방제효과를 나타냈다. 본 연구는 곤충병원세균 X. ehlersii가 새로운 해충 방제제로 개발될 가능성을 제시하고 있다.

• 한국BIM학회 논문집
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• 제8권4호
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• pp.49-59
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• 2018

Recently, the application of BIM for port & harbour facilities has been increasing, as it is widely applied to the infrastructure field both at domestic and abroad. However, the port and harbour projects still have very poor facilities information management system and the application level of BIM is very low compared to other facilities. Even if BIM is applied for those project, it is very difficult to determine in advance what information is needed without an accurate understanding of the business process. The purpose of this study is to develop a BIM framework for port & harbour facilities and to examine its applicability. To do this, we structured the classification of the port & harbour facilities and constructed object-based classification system based on ISO12006-3 standard. We also derived the BIM framework requirements from the viewpoint of process, standard, interface, and information, and confirmed the linkage of the BIM object classification system in the framework item. The applicability of the BIM framework for inspection process cases of port & harbour was examined. Accordingly, this study can solve requirement setting method, which is the non - procedural and non - systematic project information, in the BIM application process of the port & harbour project with the BIM framework. In addition, the framework is expected to be integrated into the system to play a key role in the selection of project objectives, and the ability to clearly identify the information requirements required by the BIM manager to perform the project.

• 한국학교보건학회지
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• 제34권1호
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• pp.76-86
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• 2021

Purpose: This study was conducted to describe the experience of school health teachers in regard to the COVID-19 pandemic in South Korea. Methods: We conducted a qualitative study using content analysis. Ten school health teachers were recruited from 6 elementary schools, 2 middle schools and 2 high schools in Seoul, using purposive sampling. They participated in semi-structured in-depth interviews in person or using an online communication system from January to February, 2021. Interviews were transcribed verbatim and analysed using qualitative content analysis. Results: Three main categories and nine generic categories emerged from the analysis. Firstly, it was discovered that school health teachers had psychological and physical stress to cope with COVID-19 due to the 1) fear of the unexpected infectious disease, 2) burden of having to deal with it alone, 3) breakdown of personal life and physical exhaustion and 4) heavy duty as a health teacher caused by the lack of an organic cooperation system with institutions related to school infectious diseases. Secondly, school health teachers had an increased sense of empowerment in regard to infectious disease management as a result of 1) feeling rewarded and appreciated and 2) gaining confidence and trust in infectious disease management. Finally, school health teachers experienced the urgent need for an effective response strategy for infection control because of the 1) confusion over infectious disease response due to lack of practical manuals applicable to the field as well as training, 2) disappointing response system without an expert response team dedicated to managing infectious diseases in schools, and 3) growing awareness of the need for change. Conclusion: It is expected that school health teachers' experience of COVID-19 will be used as important data for building effective and advanced school infectious disease response systems.

• 한국재료학회지
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• 제31권10호
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• pp.539-545
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• 2021

The effect of Sm₂O₃ doping on the microstructure and electrical properties of the ZPCCA-based varistors is comprehensively investigated. The increase of doping content of Sm₂O₃ results in better densification (from 5.70 to 5.82 g/cm³) and smaller mean grain size (from 7.8 to 4.1 ㎛). The breakdown electric field increases significantly from 2568 to 6800 V/cm as the doping content of Sm₂O₃ increases. The doping of Sm₂O₃ remarkably improves the nonlinear properties (increasing from 23.9 to 91 in the nonlinear coefficient and decreasing from 35.2 to 0.2 µA/cm² in the leakage current density). Meanwhile, the doping of Sm₂O₃ reduces the donor concentration (the range of 2.73 × 10¹⁸ to 1.18 × 10¹⁸ cm^-3) of bulk grain and increases the barrier height (the range of 1.10 to 1.49 eV) at the grain boundary. The density of the interface states decreases in the range of of 5.31 × 10¹² to 4.08 × 10¹² cm^-2 with the increase of doping content of Sm₂O₃. The dielectric constant decreases from 1594.8 to 507.5 with the increase of doping content of Sm₂O₃.

• 스마트미디어저널
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• 제11권5호
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• pp.56-62
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• 2022

배수지는 정수처리 된 물을 급수하기 위해 정수물을 모아두는 저장소로서, 물의 수요량에 따라 급수량을 조절하여 안정적으로 물을 공급하기 위해 배수지의 수위 관리는 매우 중요하다. 현재 배수지 내에 수위 계측 센서를 설치하여, 가압장의 펌프운영을 통해 배수지의 최적 수위를 관리하고 있으나, 센서의 오작동 및 통신두절 등 사고대응을 관리자 감시에 의존하고 있어, 사고의 위험을 안고 있다. 본 연구에서는 배수시설의 안정적 운영을 위하여, 배수지의 수위 변화 예측 인공지능 모델을 제안하였으며, 배수지 수위 변화 예측모델의 현장적용에 대한 안정성을 확인하기 위하여 수위 데이터의 결측 상황에 대한 시뮬레이션을 통하여, 실제 수위 변화값과 예측된 수위 변화값의 비교를 통하여 모델의 유용성을 확인하였다.

• 한국초전도ㆍ저온공학회논문지
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• 제12권3호
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• pp.21-24
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• 2010

A cryogenic insulation technique for a high voltage and a large current capacity of a conductor are now two big issues in a field of recent R&D projects of superconducting power devices, especially a superconducting power transformer. For the large rated currents of the power transformer, it is well known that lots of 2nd generation superconducting conductor, so called coated conductor, should be stacked together with transpositions in order to get an even distributions of the currents. We had come up with an idea of a CTCC (Continuously Transposed Coated Conductor) as a conductor for a large power superconducting transformer, and keep trying to verify the usefulness of the conductor. As one of the efforts of verifying, we prepared and tested a sample CTCC with insulations for high voltage, which includes the epoxy coating and Nomex$^{(R)}$ wrapping. This paper contains the insulation process and dielectric breakdown test results. We expect the results obtained from this experiment to improve an insulation technique for high voltages in various cryogenic environments[1,2].

• The Korean Journal of Physiology and Pharmacology
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• 제27권4호
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• pp.311-323
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• 2023

Ion homeostasis, which is regulated by ion channels, is crucial for intracellular signaling. These channels are involved in diverse signaling pathways, including cell proliferation, migration, and intracellular calcium dynamics. Consequently, ion channel dysfunction can lead to various diseases. In addition, these channels are present in the plasma membrane and intracellular organelles. However, our understanding of the function of intracellular organellar ion channels is limited. Recent advancements in electrophysiological techniques have enabled us to record ion channels within intracellular organelles and thus learn more about their functions. Autophagy is a vital process of intracellular protein degradation that facilitates the breakdown of aged, unnecessary, and harmful proteins into their amino acid residues. Lysosomes, which were previously considered protein-degrading garbage boxes, are now recognized as crucial intracellular sensors that play significant roles in normal signaling and disease pathogenesis. Lysosomes participate in various processes, including digestion, recycling, exocytosis, calcium signaling, nutrient sensing, and wound repair, highlighting the importance of ion channels in these signaling pathways. This review focuses on different lysosomal ion channels, including those associated with diseases, and provides insights into their cellular functions. By summarizing the existing knowledge and literature, this review emphasizes the need for further research in this field. Ultimately, this study aims to provide novel perspectives on the regulation of lysosomal ion channels and the significance of ion-associated signaling in intracellular functions to develop innovative therapeutic targets for rare and lysosomal storage diseases.

• 한국재료학회지
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• 제34권2호
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• pp.111-115
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• 2024

Silicon carbide (SiC) has emerged as a promising material for next-generation power semiconductor materials, due to its high thermal conductivity and high critical electric field (~3 MV/cm) with a wide bandgap of 3.3 eV. This permits SiC devices to operate at lower on-resistance and higher breakdown voltage. However, to improve device performance, advanced research is still needed to reduce point defects in the SiC epitaxial layer. This work investigated the electrical characteristics and defect properties using DLTS analysis. Four deep level defects generated by the implantation process and during epitaxial layer growth were detected. Trap parameters such as energy level, capture-cross section, trap density were obtained from an Arrhenius plot. To investigate the impact of defects on the device, a 2D TCAD simulation was conducted using the same device structure, and the extracted defect parameters were added to confirm electrical characteristics. The degradation of device performance such as an increase in on-resistance by adding trap parameters was confirmed.

• 대한전자공학회논문지SD
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• 제38권8호
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• pp.13-19
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• 2001

분자선 결정 성장법을 이용하여 성장된 서로 다른 장벽층의 두께를 갖는 $Al_{0.3}Ga_{0.7}N$ heterojunction field effect transistors (HFETs) 를 제작하여 그 특성을 비교, 관찰하였다. $Al_{0.3}Ga_{0.7}N$층의 두께에 따른 특성의 비교로부터 최적의 2 차원 전자개스 (2 dimensional electron gas) 를 가질 수 있는 $Al_{0.3}Ga_{0.7}N$/GaN HFET 소자 구조를 얻을 수 있었다. $L_g=0.6$ ${\mu}m$ 와 $W_g=34\;{\mu}m$ $Al_{0.3}Ga_{0.7}N$/GaN (20 nm/2 mm) HFET에서 Imax ($V_{gs}=1\;V$) 와 $G_{m,maX}$는 각각 1.155 A/mm 및 250ms/${\mu}m$ 이었으며 $F_t=13$ GHz 와 $F_{max}=48$ GHz의 우수한 고주파 특성을 얻을 수 있었고 2 inch 기판상에서 제작된 소자들은 5% 이하의 매우 균일한 DC 특성을 나타내었다. 이와 더불어 게이트-드레인 간의 간격에 따른 소자의 특성을 관찰함으로서 소자의 항복전압과 고주파 특성과의 상관관계를 고찰하였다.

• Applied Biological Chemistry
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• 제24권2호
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• pp.112-119
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• 1981

토양조건(土壤條件)에 따른 제초제(除草劑)의 분해양상(分解樣相)을 구명(究明)하기 위(爲)하여 유기물(有機物)의 종류(種類)및 첨가수준(添加水準), 석회시용(石灰施用) 수준(水準)이 상이(相異)한 상태(狀態)에서 토양수분함량(土壤水分含量)의 변화(變化)가 발아전처리형(發芽前處理型) 제초제(除草劑)인 butachlor와nitrofen의 분해(分解)에 미치는 영향(影響)을 규명(糾明)하기 위(爲)하여 실내시험(室內試驗)으로 실시(實施)하였다. 그 결과 토양(土壤)의 살균처리(殺菌處理)는 butachlor와 nitrofen의 분해(分解)가 현저(顯著)히 지연(遲延)되어 토양중(土壤中) 제초제(除草劑)의 분해(分解)는 주(主)로 미생물(微生物)에 의(衣)하여 약기(若杞)되었다으며, 토양(土壤)의 담수처리(湛水處理)는 밭상태(狀態)보다 제초제(除草劑)의 분해촉진효과(效果)가 컸으며, 특(特)히 nitrofen의 분해(分解)에 미치는 담수(湛水)의 효과(效果)는 현저(顯著)하였다. 밭상태()에서의 nitrofen의 반감기()는 butachlor 보다 2배정도() 길었다. 볏짚의 첨가(添加)는 벼그루터기에 비(比)하여 토양중(土壤中) 제초제(除草劑)의 분해촉진효과(效果)가 높았으며 볏짚의 첨가수준(水準)이 1%(w/w) 이상(以上)일때는 토양중(土壤中) butachlor의 분해(分解)는 지연(遲延)되었으나 nitrofen의 분해(分解)는 촉진(促進)되었다. 석회시용(石灰施用)은 토양중(土壤中) 제초제(除草劑)의 분해(分解)를 조장(助長)하였으나 pH와의 직접적(直接的)인 영향(影響)은 없었다.