• 대한환경공학회지
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• 제27권6호
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• pp.567-572
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• 2005

본 연구에서는 용존공기부상법(DAF)을 이용한 정수처리 공정에 오존을 도입하기 위하여 실험실 규모의 실험이 수행되었다. 오존의 수처리 적용시 공정제어 인자로 활용할 수 있는 I.D, $k_c$, 오존-Ct 및 OH 라디칼-Ct 등에 대한 반응속도론적 연구를 실시하였다. 또한 원수, DAF 처리수 및 여과수에 대한 오존처리 실험을 실시하여 오존공정의 최적 위치 및 주입량을 도출하였다. 실험 결과 오존-Ct와 OH 라디칼-Ct는 DAF 처리수에서 가장 높게 측정되었으며, DAF 공정의 체류시간인 30분 이후에도 계속적으로 유지되었다. 또한 각 공정수에 대한 오존처리 실험을 실시한 결과, 중오존이 전 후오존에 비해 높은 효율을 기대할 수 있을 것으로 나타났으며, 최적 오존주입농도는 $1{\sim}2\;mg/L$로 판단되었다. 이러한 결과로부터 중오존 / DAF(ozoflotation) 공정 도입을 위한 기초자료로서 활용하고자 하였다.

• 한국물환경학회지
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• 제22권4호
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• pp.672-677
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• 2006

Ozone/UV combined process is an effective technique to enhance generation of OH radical which is non-selective and powerful oxidant. The objective of this study is to evaluate the inactivation rates of B. subtilis spores by three candidate processes (ozone alone, UV alone, ozone/UV combined processes) at 4 and $20^{\circ}$ and to investigate the effects of OH radical on inactivation of B. subtilis spores. On the UV alone process, required UV dosages for lag phase and 3-log inactivation of B. subtilis spores were determined as $8.9mJ/cm^2$ and $47mJ/cm^2$. However, the inactivation of B. subtilis spores didn't occured beyond 4.5-log inactivation despite increasing UV dose. The inactivation of B. subtilis spores by ozone alone and ozone/UV combined process was investigated with ozone CT (Concentration of disinfectant ${\times}$ Contact time) concept. As a result, inactivation of B. subtilis spores by ozone/UV combined process was faster than by ozone alone, and especially $CT_{lag}$ value B. subtilis spores in the presence and absence of t-BuOH, OH radical scavenger, was investigated to evaluate effects of OH radical formed during ozone/UV combined process. We found that OH radical plays important roles on inactivation of B. subtilis spores.

• 상하수도학회지
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• 제27권1호
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• pp.39-47
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• 2013

This study demonstrates the oxidative degradation of pharmaceutical compounds during ozonation of surface waters in Ulsan. Diclofenac, carbamazepine, bezafibrate, and ibuprofen were selected as surrogate pharmaceutical compounds, and ozonation experiments were performed using raw waters collected from the Sayeon Dam and the Hoeya Dam in Ulsan. Diclofenac and carbamazepine which have high reactivity with molecular ozone showed higher removal efficiencies than bezafibrate and ibuprofen during ozonation. The addition of tert-butanol, a hydroxyl radical scavenger, increased the removal efficiencies of diclofenac and carbamazepine by increasing the ozone exposure. However, the oxidation of bezafibrate and ibuprofen was inhibited by the presence of tert-butanol due to the suppression of the exposure to hydroxyl radical. The elimination of the selected pharmaceuticals could be successfully predicted by the kinetic model base on the $R_{ct}$ concept. Depending on the experimental condition, $R_{ct}$ values were determined to be $(1.54{\sim}3.32){\times}10^{-7}$ and $(1.19{\sim}3.04){\times}10^{-7}$ for the Sayeon Dam and the Hoeya Dam waters, respectively. Relatively high $R_{ct}$ values indicate that the conversion of $O_3$ into $^{\cdot}OH$ is more pronounced for surface waters in Ulsan compared to other water sources.

• Environmental Engineering Research
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• 제11권6호
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• pp.293-302
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• 2006

The reaction of ozone with NOM (Natural Organic Matter) can occur by two different pathways: that involving molecular ozone and by way of reactions with hydroxyl radicals which are produced from the decomposition of molecular ozone. As such, the formation of ketoacids and Assimilable Organic Carbon (AOC) can be controlled by controlling the pathway by which ozone reacts with NOM. The ratios of $[OH{\cdot}]/[O_3]$ ($R_{CT}$ values) were determined under the various ozonation conditions. The $R_{CT}$ values increased with increasing initial ozone concentration. The $R_{CT}$ values (ranges from 10 to $35^{\circ}C$) increased linearly as temperature increased (within the range from 10 to $35^{\circ}C$). However, $R_{CT}$ was independent of hydraulic retention time (HRT). Operational conditions were found to affect the formation of AOC. The conditions where the molecular ozone reaction predominated resulted in an increase in the formation of AOC.

• 대한환경공학회지
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• 제27권6호
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• pp.663-669
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• 2005

본 연구에서는 정수처리 공정에서 오존을 보다 효율적으로 적용하기 위하여 수중의 오존소비특성을 파악하고자 하였다. 오존의 소비특성을 측정하기 위하여 흐름주입분석법(FIA: Flow injection analysis)의 원리를 이용하여 오존분해속도 측정 자동화장치를 제작하였다. 수중의 오존농도를 연속적으로 측정함으로써 오존의 소비 경향은 순간적으로 오존이 소모되는 구간(I.D: instantaneous ozone demand)과 의사 1차 반응($k_c$: pseudo first-order rate constant)으로 소모되는 두 구간으로 나누어지며, 각 구간에서 오존 주입량에 의하여 영향을 받는 것으로 나타났다. 또한 I.D와 $k_c$값을 이용하여 구한 모델식으로부터 시간에 따른 오존 잔류농도를 예측할 수 있었으며, 예측된 모델간은 실험값과 비교하였을 때 거의 일치하는 것을 알 수 있었다. OH 라디칼의 농도 및 $R_{ct}$는 OH 라디칼 probe compound를 이용하여 간접적으로 계산하였다. I.D와 $k_c$ 구간에서 OH 라디칼 생성 경향을 파악할 수 있었으며, OH 라디칼 생성 또한 오존 주입량에 의하여 영향을 받는다는 것을 확인하였다. 마지막으로 정수처리 공정 및 계절에 따른 수질 차이에 의해서 오존소비인자가 변화하는 것을 확인하였으며, 이에 따라 오존공정의 적절한 도입위치 및 주입량을 효과적으로 결정해야 할 것으로 판단되었다.

• 대한본초학회지
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• 제34권3호
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• pp.9-17
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• 2019

Objectives : This study was performed to compare the effect of two Cudrania tricuspidata cultivars; Sancheong native (CT) and varieties in china(SCT) on immediate hypersensitivity of the anaphylactic type and Ova-induced allergic asthma mouse model by calculating serum cytokines and IgE. Methods : We investigated the free radical scavanging effect and quantify total phenol contents and total flavonoids of two Cudrania tricuspidata cultivars; Sancheong native(CT) and varieties in china(SCT). The sample was extracted by 80% EtOH. To induce the allergic asthma, in the control group and the CT group, mice of each group were sensitized intraperitoneally with ovalbumin (OVA) solution at the 1st, the 7th and the 14th day. After then, sensitization was performed by aerosol allergen challenges with 1% OVA solution intratracheally at the 21th, the 23th, 25th and the 27th day. At the 29th day, the mice were killed and the changes of interferon-${\gamma}$, interleukin-4, 5 and 10, total IgE and OVA-specific IgE in serum were checked. Results : CT inhibited compound 48/80-induced systemic anaphylaxis 90% with a dose of 100 mg/kg body weight at 1 hr before injection of compound 48/80. In the allergic asthma mouse model, IFN-${\gamma}$ was did not increased in the CT and SCT group than that in the control group. IL-4, IL-5, the total IgE and OVA-specific IgE were decreased in the CT group as compared with the control group and these results were statistically significant. Conclusions : Considering the above experimental results, this study showed that Sancheong native cultivar could reduce the allergic reaction.

• Journal of Trauma and Injury
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• 제20권1호
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• pp.52-56
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• 2007

Marjolin's ulcer is a rare and often-aggressive cutaneous malignancy that arises in previously traumatized or chronically inflamed skin, particularly after burns. We experienced two cases after burns. Case I involved a forty eight year-old man who had suffered from a flame burn at the parietal scalp area, where had been initially described three years earlier as a full-thickness wound including the pericranium. The man consulted us for a persistent ulcerative and infected wound on the burned lesion during the last 24 months, which turned out on the contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI) to be the squamous cell carcinoma with involving the skull and the dura mater. Although the posterior auricular lymph node was enlarged on the ipsilateral side, recent positron emission tomography (PET) CT did not show any metastatic lesion. It was impossible for us to resect the intracranial involvement of the tumor radically, and the postoperative PET CT still showed a focal fluorodeoxyglucose (FDG) uptake around the wall of the superior sagittal sinus. We think that an aggressive combined approach is essential for treatment in early stages for a high success rate, before the intracranial structures are involved because there is no consensus on the treatment for advanced disease, and the results are generally poor. Case 1 also did not involve a radical resection because of the intracranial invasion to the wall of superior sagittal sinus and the possibility of damage to the major cortical veins. He received adjuvant radiotherapy and must be followed periodically. Case 2 involved an eighty six year-old women who suffered from a painful scalp ulcer lesion after flame burns three years earlier. Unlike case 1, neither tumor infiltration into the dura nor lymph node enlargement was observed on the contrast-enhanced computed tomography (CT), magnetic resonance imaging (MRI), or positron emission tomography (PET) CT. We did a radical resection of the tumor, including the involved bone, and a cranioplasty with bone cement.

• 생명과학회지
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• 제27권6호
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• pp.640-645
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• 2017

누리장나무의 잎과 줄기는 예로부터 항고혈압, 관절염, 류마티스 관절염, 항염증 등을 치료하는 민간약재로 사용되어 왔다. 본 연구에서는 누리장나무의 잎 추출물과 그 분획물의 항산화 및 항염증 소재로서의 활성가능성을 확인하기 위하여 수행되었다. 누리장나무 잎의 ethanol (EtOH)로 추출물과 이 추출물을 분획하여 얻은 hexane, chloroform ($CHCl_3$), ethyl acetate (EtOAc), n-butanol (BuOH) 분획물들의 총 폴리페놀 함량을 비교한 결과, 총 폴리페놀 함량은 EtOAc 분획물($78.08{\mu}g/mg$)과 BuOH 분획물($77.54{\mu}g/mg$)에서 높게 측정되었다. 각 분획물의 항산화 활성을 비교한 결과, 폴리페놀 함량이 높은 EtOAc 분획물과 BuOH 분획물에서 높은 DPPH (1,1-diphenyl-2-picrylhydrazyl) 및 ABTS (2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid)) radical 소거활성을 나타내었다. 그리고 xanthine oxidase 저해활성은 $CHCl_3$ 분획물($IC_{50}=4.43{\mu}g/ml$)과 EtOAc 분획물($IC_{50}=5.69{\mu}g/ml$)에서 높게 나타났다. EtOAc 분획물은 RAW 264.7 세포에서 lipopolysaccharide (LPS)로 유도된 nitric oxide (NO)의 생성을 효과적으로 억제하였다($IC_{50}=18.87{\mu}g/ml$). 또한, EtOAc 분획물($100{\mu}g/ml$)은 LPS로 지극한 RAW 264.7 세포에서 tumor necrosis factor ${\alpha}$ ($TNF-{\alpha}$)와 interleukin-6 (IL-6)의 생성과 inducible nitric oxide synthase (iNOS)와 cyclooxygenase-2 (COX-2) 단백질의 발현을 효과적으로 억제하였다. 본 연구결과는 누리장나무 잎 추출물과 분획물이 항산화 및 항염증 소재로서의 활용가능성이 있음을 제시해 준다.

• 한국생산제조학회지
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• 제20권3호
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• pp.342-349
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• 2011

The purpose of this paper is to describe experimental results about the butt welding and bead on plate welding of the high power Continuous Wave (CW) Fiber laser for Ultra-low carbon Interstitial Free(IF) steel plate for gear part of car. After being welded of the gear parts by the fiber laser and electron beam Microstructures of melting zone had been mixed acicular, granular bainitic, quasi-polygonal and widmanstatten ferrite because of a radical thermal diffusion after welding, difference of critical volume and grain size. As a result of experiment, when gear parts were welded by the fiber laser and electron beam, the fiber laser welding has been stable properties without internal defects more than the electron beam welding. Therefore it has the very advantages of welding high quality and productivity more than conventional melting method. The optimal welding processing parameters for gear parts were as follows : the laser power and welding speed were 3kWatt, 30mm/sec respectively. At this time heat input was $21.2{\times}10^3J/cm^2$.

• Bulletin of the Korean Chemical Society
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• 제33권4호
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• pp.1290-1296
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• 2012

Fenton reaction and iron autoxidation have been debated for the major process in ROS mediated DNA cleavage. We compared both processes on iron oxidation, DNA cleavage, and cyclic voltammetric experiment at different pHs. Both oxidation reactions were preferred at basic pH condition, unlike DNA cleavage. This indicates that iron oxidation and the following steps probably occur separately. The ROS generated from autoxidation seems to be superoxide radical since sod exerted the best inhibition on DNA cleavage when $H_2O_2$ was absent. In comparison of cyclic voltammograms of $Fe^{2+}$ in NaCl solution and phosphate buffer, DNA addition to phosphate buffer induced significant change in the redox cycle of iron, indicating that iron may bind DNA as a complex with phosphate. Different pulse voltammogram in the presence of ctDNA suggest that iron ions are recyclable at acidic pH, whereas they may form an electrically stable complex with DNA at high pH condition.