• 한국응용과학기술학회지
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• 제29권4호
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• pp.570-576
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• 2012

본 연구에서는 무격막식 전기분해 처리된 해수를 산화제로하는 NO 산화반응의 특성에 대해 실험적으로 살펴보았다. 폐순환 정전류 전기분해 시스템을 통해전해 시간이 길어질수록 전해수의 유효 염소농도와 온도, 염소산 이온의 비율이 증가함을 확인하였다. 전해수가 채워진 버블링 반응기에서 전해수의 유효염소농도와 온도에 비례하여 $NO_2$로 산화되는 NO의 양이 증가하였다. 또한 산화되어 생성된 $NO_2$는 전해수에 용해되어 $HNO_3{^-}$ 이온으로 존재함을 확인하였다.

• 한국미생물·생명공학회지
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• 제50권3호
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• pp.387-394
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• 2022

Verotoxin-1 (VT-1) or Shiga-like toxin 1 (Stx-1) is produced by enterohemorrhagic Escherichia coli (EHEC) and is an AB5 holotoxin with a strong inhibitor of protein synthesis. VT-1 is a type 2 ribosome-inactivating protein (RIP) that has been shown to have cytotoxic and anticancer potential by inducing necrosis, apoptosis, and cell cycle arrest, making it a promising antitumor candidate. Here, we tested the cytotoxicity of VT-1 on CaCo2 and NCM425 cell lines and the results showed that VT-1 was more potent on CaCo2. Morphological changes were also evaluated on the cellular level and the results showed that VT-1 caused a decrease in viable cell count, altered cell membrane permeability, and an increase in total nuclear intensity. On the other hand, VT-1 displayed a lesser impact on mitochondrial membrane potential (MMP) and cytochrome c release. On the expression of caspases 3 and 9, VT-1 exhibited an insignificant effect on both which alongside the mitochondrial membrane potential (MMP) and cytochrome c results, might indicate that CaCo2 suffered from the necrosis process as a mechanism of cell death after exposure to VT-1.

• 자원환경지질
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• 제42권5호
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• pp.427-434
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• 2009

유류 및 중금속으로 오염된 토양에서 Pb 및 Cd에 내성을 갖는 미생물을 분리하여 미생물 내 중금속 흡착 특성을 조사하였다. 분리한 토착미생물의 Pb 및 Cd의 흡착특성과 흡착에 영향을 미치는 요인 중에 생장단계, 중금속 농도, 생물량, pH, 온도에 따른 영향을 비교하였다. 또한 흡착등온식을 적용하여 중금속의 흡착용량과 흡착강도를 알아보았다. 낮은 중금속 초기 농도와 높은 생물량에서 높은 중금속 제거 효율을 가지며 중금속 마다 다른 흡착 효율을 보여 주었다. 흡착 효율은 미생물 생장 말기, pH 5~9 조건에서 최적의 효율을 나타내었으나, 25~$35^{\circ}C$에서 온도 변화에 따른 영향은 미미하였다. 생물흡착 과정을 Langmuir 등온 흡착식에 적용하면, 이론적 최대 흡착량은 Pb와 Cd에 대해서 각각 62.11과 192.31 mg/g로 나타났고, $R^2$가 0.71과 0.98로 계산되었다. Cd는 세포 표면의 단일 층에 단분자 흡착에 의한 생물흡착이 진행되었으나, Pb는 미생물 대사 작용을 통한 세포 내로의 축적 작용과 미생물 내 음이온과의 반응에 의한 침전물 형성작용 둥을 통하여 생물흡착이 진행된 것으로 판단된다.

• 해양환경안전학회지
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• 제15권2호
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• pp.151-156
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• 2009

이 연구에서는 선박용 팬일유니트의 엇갈림 냉각관 주위 유동특성을 실험적으로 고찰하였다. 입자영상유속계를 이용하여 입구유속기준 레이놀즈수 Re = $1.5{\times}10^3$에서 Re = $2.5{\times}10^3$까지 계측결과를 얻었다. 그 곁과 유동은 흐름방향으로 빠른 속도로 발달하여 비교적 짧은 거리 후방에 공간적인 주기성을 나타내었다. 유동이 발달하는 영역에서는 레이놀즈수에 의존하는 경향이 크게 나타났으나 공간적 주기성에 미치는 레이놀즈수의 영향은 크지 않았다.

• 한국해양공학회지
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• 제20권4호
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• pp.76-82
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• 2006

The large-eddy simulation(LES) technique, based an a message passing interface method(MPI), was applied to investigate the turbulent flaw phenomena around a ship. The Smagorinski model was used in the present LES simulation to simulate the turbulent flaw around a ship. The SPMD(sidsngle program multiple data) technique was used for parallelization of the program using MPI. All computations were performed an a 24-node PC cluster parallel machine, composed of 2.6 GHz CPU, which had been installed in the Advanced Ship Engineering Research Center(ASERC). Numerical simulations were performed for the Wigley hull, and the Series 60 hull(CB=0.6) using 1/4-, 1/2-, 1- and 2-million grid systems and the computational results had been compared to the experimental ones.

• 산업경영시스템학회지
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• 제36권2호
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• pp.32-38
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• 2013

In recent years, anti-PID (Potential Induced Degradation) technologies have been studied and developed at various stages throughout the solar value chain from solar cells to systems in an effort to enhance long-term reliability of the photovoltaics (PV) system. Such technologies and applications must bring in profits economically for both manufacturers of solar cell/module and investors of PV systems, simultaneously for the development of the PV industry. In this study two selected anti-PID technologies, ES (modification of emitter structure) and ARC (modification of anti-reflective coating) were compared based on the economic features of both a cell maker with 60MW production capacity and an investor of 1MW PV power plant. As a result of this study, it is shown that ARC anti-PID technology can ensure more profits over ES technology for both the cell manufacturer and the investor of PV power plant.

• Journal of Animal Science and Technology
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• 제62권4호
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• pp.543-552
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• 2020

For efficient prevention and treatment of enteric colibacillosis, understanding about latest virulence factors and antimicrobial resistance of Escherichia coli is essentially needed. The aim of this study was to survey antimicrobial resistance and determine the prevalence of fimbriae and enterotoxin genes among 118 pathogenic E. coli isolates obtained from Korean pigs with diarrhea between 2016 and 2017. The genes for the toxins and adhesins were amplified by polymerase chain reaction (PCR). The susceptibility of the E. coli isolates to antimicrobials were tested using the standard Kirby-Bauer disk diffusion method. The most prevalent fimbrial antigen was F18 (40.7%), followed by F4 (16.9%), and the most prevalent combinations of toxin genes were Stx2e (21.2%), STb:EAST-1 (19.5%), and STa:STb (16.9%), respectively. Among the pathotypes, enterotoxigenic E. coli (ETEC) was the most predominant (67.8%), followed by Shiga-toxin producing E. coli (STEC, 23.7%). We confirmed high resistance rates to chloramphenicol (88.1%), tetracycline (86.4%), streptomycin (86.4%), and ampicillin (86.4%). And the majorities of isolates (90.7%) showed multi-drug resistance which means having resistance to 3 or more subclasses of antimicrobials. Results of this study can be a source of valuable data for investigating the epidemiology of and control measures for enteric colibacillosis in Korean piggeries.

• 수산해양기술연구
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• 제40권2호
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• pp.144-148
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• 2004

해저에 설치된 파이프에서 분출되는 기포에 의해 형성된 강한 수평압력분포를 이용하여 선박을 신속 하고 정밀하게 유도, 정박시키는 도선시스템으로 항구, 협수로, 해협 등과 같이 복잡한 수상, 수중 장애물 지역에서 선박을 신속하고 정밀하게 유도함과 동시에 협소한 부두에 안전하게 선박을 정박시키기 위하여 본 도선 시스템을 고안하였다.

• Journal of Welding and Joining
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• 제27권3호
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• pp.92-96
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• 2009

Metallic sandwich plate has many good properties such as high specific stiffness, high specific strength, good impact absorptivity, effective thermal insulation and soundproofing. In our study, a new bonding method, 3-layer roll projection welding, is introduced to fabricate the metallic sandwich plate. The new method uses a pair of roll electrodes like the seam welding, and projection welding is made at two internal interfaces of the 3-layer weldment consisting of a structured inner sheet and a pair of skin sheets. During the welding process, skin sheet temperature are measured to produce metallic sandwich plate with uniform and good quality. But it is difficult to observe or measure the temperature at the welding points during welding process because the welding points exist at the internal interfaces. Therefore FEM numerical analysis using ABAQUS is conducted to estimate the generated heat at the welding points with different welding conditions.

• 대한조선학회논문집
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• 제54권2호
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• pp.125-131
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• 2017

In order to develop test and performance analysis techniques for a CRP propulsion, a CRP dynamometer which can be installed inside the model ship was designed and manufactured. The object ship was the 16000TEU container carrier, which has test results for the single propeller. The design concept of the present CRP is that forward & after propellers have the same power ratio and their RPM ratio is 0.75:1. To begin with, we checked the performance of the CRP dynamometer through the calibration and then installed it inside the model ship. After the model ship setup including the design CRP and the rudder in the Large Cavitation Tunnel(LCT), a series of model tests composed of power ratio check, propeller behind wake(PBW) test, cavitation observation and pressure fluctuation tests was conducted. Through the model test and data analysis for CRP, the experimental technique was established and the improved method for CRP design was suggested.