Oxidation of erythromycin, sulfamethazine and sulfathiazole by ozone was experimentally investigated to see the effects of background water quality such as ultrapure water, humic acid and biologically treated wastewater and water temperature on the removal rate, consequently to provide design information when the ozone treatment process is adopted. Initial concentration of the antibiotics was spiked to 10 μg/l and ozone dose was 1, 2, 3, 5, 8 mg/l. While the removal rate of erythromycin under ultrapure water background by ozone oxidation was over 99%, that under humic acid and biologically treated wastewater background was markedly reduced to the range of 59.8%~99% and 17.0%~99%, respectively. When water temperature is decreased from 20℃ to 4℃, the removal rate is reduced from the range of 17.0%~99% to the range of 9.4%~97.4% under biologically treated wastewater background. The effects of background and temperature on the removal rate of sulfamethazine and sulfathiazole were similar to erythromycin, but the degree was different. Therefore, it is concluded that the background of water to be treated as well as water temperature should be taken into consideration when the design factor such as ozone dose is determined to meet the treatment objective in the ozone treatment process.

In this study, refined finite element (FE) analyses intended to evaluate the capacity of the existing water purification plant structures against seismic force are conducted with an aim to predict possibility generating tension crack and compression crushing. The FE models for three types of main plant structures were constructed to take ground condition, boundary condition, and water interaction into consideration for advanced simulation. The nonlinear dynamic analyses were performed by using ground motion data which have been used for seismic design. Both compression crushing and tention crack, which are distributed over concrete plant structures during peak ground acceleration (PGA), are investigated by analyzing failure possibility controlled with the strain limits. After observing FE analysis results, it is possible to predict tenstion cracking which can be found at some parts of the main structure.

ASCE 4 requires that a hard stop be built around the seismic isolation system in nuclear power plants. In order to maintain the function of the isolation system, this hard stop is required to have clearance-to-stop, which should be no less than the 90th-percentile displacements for 150% Design Basis Earthquake (DBE) shaking. Huang et al. calculated clearance-to-stop by using a Latin Hypercube Sampling technique, without considering the rocking behavior of the isolated structure. This paper investigates the effects on estimation of clearance-to-stop due to 1) rocking behavior of the isolated structure and 2) sampling technique for considering the uncertainties of isolation system. This paper explains the simplified analysis model to consider the rocking behavior of the isolated structure, and the input earthquakes recorded at Diablo Canyon in the western United States. In order to more accurately approximate the distribution tail of the horizontal displacement in the isolated structure, a modified Latin Hypercube Sampling technique is proposed, and then this technique was applied to consider the uncertainty of the isolation system. Through the use of this technique, it was found that rocking behavior has no significant effect on horizontal displacement (and thus clearance-to-stop) of the isolated structure, and the modified Latin Hypercube Sampling technique more accurately approximates the distribution tail of the horizontal displacement than the existing Latin Hypercube Sampling technique.

The worldwide abundance of various jellyfish appears to have increased in coastal ecosystems in recent years. The enormous jellyfish blooms cause a variety of problems for the local ecology, fisheries, and aquatic-sports in coastal locations. In this study, jellyfish sting protection net was installed to ensure the safety and reduction of the inflow into the Haeundae beach. In order to confirm the stability of the protection net, the tension for protection net was measured from variation of current speed. The periods for maximum tension were observed correspond to the periods of maximum current speed. The maximum tension for protection net was measured up to 4,100 kg. From field evaluations, the jellyfish sting protection net has demonstrated to stability from the current and tide in the Haeundae beach.

Ultra-thin liquid films on solid substrates in contact with the saturated vapor are studied by using molecular dynamics simulation. The properties of evaporation and condensation of the films of various adsorptive strengths and thicknesses are obtained during the quasi-steady film evolution. Net condensations occur when the ultra-thin films on the high energy surface come into contact with the saturated vapor phase because the normal film pressure stays lower than the saturated vapor pressure. The net condensation rate is higher for the material combination of higher adsorptive strength. It becomes more so when the film thickness is of a lesser size. On the other hand, that of lower adsorptive strength has lower net condensation rate and depends less on the film thickness. Therefore, the size effect of the condensation phenomenon is more significant for the system of a higher adsorptive strength. This properties come from the state of ultra-thin film, which can be quantified by using disjoining pressure in the quasi-steady processes. These results have implications in practical problems concerning the moving contact line when the precursor film formation is critica

본 연구에서는 기능성 식품 및 화장품 소재로써 갈색 느티만가닥버섯(Hypsizygus marmoreus)의 이용가능성을 조사하기 위해서 갈색 느티만가닥버섯 메탄올 추출물의 항산화 활성 및 tyrosinase 저해 효과를 갓(pileus)과 대(stipes)로 분리하여 부위별로 조사하였다. 메탄올 추출물 중 갓과 대의 총 폴리페놀 함량은 각각 8.7±3.27ug/mg과 5.6±2.85ug/mg이었고플라보노이드 함량은 각각 2.8±3.81ug/mg과 1.4±1.95ug/mg이었으며 총 폴리페놀과 플라보노이드 함량 모두 대보다 갓에서 높게 나타났다. Tyrosinase 저해 활성은 추출물의 농도에 따라 증가하는 경향을 나타내었으나 양성 대조구로 사용한 2% 알부틴(arbutin)과 비교했을 때 1200mg/ml의 고농도에서도 갓은66.9%, 대는 57.97%의 낮은 저해 활성을 나타내었다.항산화 활성은 DPPH에 의한 라디칼소거 활성을 측정하여 확인하였으며 갓과 대의 DPPH 라디칼 소거능은 20mg/ml의 농도에서도 각각 52.55%와 30.35%로 낮게 나타났다. 추출물이 B16BL6 mouse melanomacell에 미치는 영향을 알아보기 위해 WST-1 assay (4-[3-(4-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulphonate)를 이용하여 세포생존율을 조사하였으며 갓과 대 모두 200-2,000ug/ml의 농도로처리하였을 때 100% 이상의 생존율을 나타내었고추출물의 처리 농도가 증가함에 따라 세포생존율도증가하는 경향을 나타내었으며 양성대조군인 0.04%adenosine을 처리한 경우보다 높게 나타났다.

이 연구에서는 목재의 효율적인 이용과 그 이용확대를 목적으로, 가문비나무를 이용한 직교형 적층재를 제작하였고, 동적탄성계수에 미치는 섬유직각방향라미나의 연륜경각의 영향을 조사하였다. 또한, 동적탄성계수로부터 정적 휨 강도성능을 예측하였다. 3층 모두가 섬유직각방향라미나로 구성된 평행형적층재(P⊥타입)의 동적탄성계수는 연륜경각의 영향이 현저히 나타났고, 연륜경각 90∘에서 가장 높은 값을 나타내었고, 45∘에서 가장 낮은 값을 나타내었다. 중층에 섬유방향라미나를 배열하는 것에 의해 동적탄성계수는 현저히 향상되었다. 표층에 섬유직각방향라미나로 구성된 직교형 적층재 (C⊥타입)의 경우, 동적탄성계수는 연륜경각 90∘>0∘>45∘의 순이었으나, 연륜경각에 의한 차이는 평행형 적층재에 비해 현저히 감소하였다. 중층에 섬유직각방향라미나를 배열한 직교형 적층재 (C∥ 타입)의 경우, 동적탄성계수는 P⊥타입 및 C⊥타입과 역으로 연륜경각 45∘에서 가장 높은 값을 나타내었고, 그 값은 P∥ 타입보다 약간 적은 값을 나타내는 것이 확인되었다. 동적탄성계수와 정적 휨강도성능과의 상관회귀의 결과로부터 평행형 및 직교형 적층재의 정적 휨 강도성능이 동적탄성계수로부터 예측 가능한 것이 확인되었다. 단 C⊥타입의 경우, 충분한 시험편의 개수로 상관회귀를 실시할 필요가 있었다.

본 연구에서는 내식성이 우수한 동합금에 대하여 내구성 향상을 위해 쇼트피닝 시간을 변수로 표면 개질하여 전기화학적 특성과 조직 변화를 관찰하였다. 그 결과 쇼트피닝 후 표면에 전체적으로 요철이 발생하였으며, 시간이 증가할수록 커버리지 향상에 따른 균질화 현상이 관찰되었다. 또한 쇼트피닝된 모든 시험편에서 경도가 향상되었으며, 쇼트피닝 시간이 3.5분일 때 52 %의 경도향상을 나타냈다. 그리고 이때 전기화학적 특성은 쇼트피닝을 실시하지 않은 경우와 유사하였다