• Journal of Korean Society of Environmental Engineers
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• v.22 no.1
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• pp.91-101
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• 2000

The emission sources of volatile organic compounds (VOCs) are wastewater treatment plants. sanitary landfills, automobile industries, and so on. The VOCs are harmful to human beings because of their toxicity and carcinogenicity, and cause the serious air pollution problem producing ozone ($O_3$) as a result of photochemical reaction. To investigate the emission of VOCs from wastewater treatment plant, aeration basins at the City of Los Angeles' Hyperion Treatment Plant were selected and measured flux was compared with calculated flux. For compounds commonly associated with wastewater (DCM, TCM, PCE, UM, DCB, UND) and not expected in vehicle exhaust or ambient air coming off the ocean, concentrations immediately downwind of the aeration basins were a factor of ten or higher than those measured in the upwind air. The airborne flux of less degradable or non-biodegradable compounds, e.g., DCE, DCM, TCA, DCA, TCM, PCE, DCB, through an imaginary plane at the downwind side of the aeration basins was in agreement with the estimated flux from measured liquid phase concentrations. Henry's constant. aeration rate, and an assumption of bubble saturation. For several compounds (PCE, DCE, TCA), the ratio (measured flux/calculated flux) is almost unity.

• Journal of the Korean Society for Marine Environment & Energy
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• v.10 no.4
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• pp.187-192
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• 2007

Impact on cylindrical surface caused by plunging breaking waves is investigated experimentally. The breaking waves are generated in a wave flume by decreasing the wave maker frequencies linearly and focusing the generated wave components at one specific location. The breaking wave packets are based on constant wave steepness spectrum. Three inclination angles of cylinder are applied to examine the effect of contact angle between cylinder and front surface of breaking waves. Also, the effect of cylinder diameter on pressure distribution and its peak value is investigated by adopting three cylinders with different diameters. The longitudinal location of cylinder is slightly moved in eight different points to find out a probable maximum value of impact pressure. The pressures and total force on cylinder surface are measured by piezo-electric pressure sensors and 3-components load cell with 30kHz sampling rate. The variation of peak impact pressures and forces is analyzed in terms of cylinder diameter, inclination angle and location. Also, the pressure distribution on cylindrical surface is examined. The cylinder location and surface position are more important parameters that govern the magnitude and shape of peak pressures, while the cylinder diameter and inclined angle are relatively insignificant. In a certain conditions, the impact phenomenon becomes very unstable which results in a large variation of measured valves in repeated runs.

• Applied Biological Chemistry
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• v.40 no.5
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• pp.375-379
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• 1997

Two ribosome-inactivating proteins, PRIP 1 and PRIP 2 have been isolated from the leaves of $Cucurbita\;moschata\;D_{UCHESNE}$. Crude extracts were purified through ammonium sulfate precipitation and column chromatography using DE-52 cellulose, S-Sepharose, FPLC Suprose 12 HR and FPLC Mono-S. The molecular weights of PRIP 1 and PRIP 2 were 31,000 and 30,500, respectively. PRIP 2 was thermostabe and maintained its activity even after the incubation of the protein at $50^{\circ}C$ for 30 min. In a cell free in vitro translation system using rabbit reticulocyte lysate, protein synthesis was inhibited by the addition of PRIP 1 and PRIP 2. The $IC_{50}$ of PRIP 1 and PRIP 2 were 0.82 nM and 0.79 nM, respectively. The comparison of N-terminal amino acid sequences of the PRIP 1 and PRIP 2 with known RIPs revealed that PRIP 1 shows sequence similarity with Luffin B from Luffa cylindrica and Trichokirin from Trichosanthes kirilowii Maximowicz and PRH) 2 has sequence similarity with Momordin II and MAP 30 from Momordica charantia.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.6
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• pp.1056-1063
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• 2006

Thermal evaporated 10 nm-Ni/l nm-Ir/(or polycrystalline)p-Si(100) and 10 nm-$Ni_{50}Co_{50}$/(or polycrystalline)p-Si(100) films were thermally annealed using rapid thermal annealing fur 40 sec at $300{\sim}1200^{\circ}C$. The annealed bilayer structure developed into Ni(Ir or Co)Si and resulting changes in sheet resistance, microstructure, phase and composition were investigated using a four-point probe, a scanning electron microscopy, a field ion beam, an X-ray diffractometer and an Auger electron spectroscope. The final thickness of Ir- and Co-inserted nickel silicides on single crystal silicon was approximately 20$\sim$40 nm and maintained its sheet resistance below 20 $\Omega$/sq. after the silicidation annealing at $1000^{\circ}C$. The ones on polysilicon had thickness of 20$\sim$55 nm and remained low resistance up to $850^{\circ}C$. A possible reason fur the improved thermal stability of the silicides formed on single crystal silicon substrate is the role of Ir and Co in preventing $NiSi_2$ transformation. Ir and Co also improved thermal stability of silicides formed on polysilicon substrate, but this enhancement was lessened due to the formation of high resistant phases and also a result of silicon mixing during high temperature diffusion. Ir-inserted nickel silicides showed surface roughness below 3 nm, which is appropriate for nano process. In conclusion, the proposed Ir- and Co- inserted nickel silicides may be superior over the conventional nickel monosilicides due to improved thermal stability.

• Korean Journal of Microbiology
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• v.47 no.4
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• pp.364-374
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• 2011

Lactobacillus brevis DK25 isolated from Dongchimi was identified by physiological and biochemical tests and 16S rDNA sequence analysis. Bacteriocin of L. brevis DK25 exhibits inhibitory activity against Enterococcus faecalis and Listeria monocytogenes when using agar well diffusion method. Maximal production of bacteriocin was reached in the beginning of the stationary phase, and inhibitory activity declined after the late stationary phase. This result suggested that bacteriocin was produced in a growth-associated manner. Complete inactivation of bacteriocin activity was observed after treatment with protease, but the activity was stable between pH 4-9 and heat resistant (30 min at $100^{\circ}C$). Bacteriocin showed a concentration-dependent antimicrobial activity against L. monocytogenes KCTC 3569. Moreover, the application experiment showed that combination of bacteriocin (320 AU/ml) with potassium benzoate (0.05%) could significantly reduce the counts of L. monocytogenes KCTC 3569 in mayonnaise during storage at 4 or $25^{\circ}C$ for 10 days. Thus, bacteriocin from L. brevis DK25 may be used for hurdle technology by combination with potassium benzoate in order to increase pathogenic bacteria inactivation in food processing and food safety control.

• Journal of Life Science
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• v.12 no.1
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• pp.77-86
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• 2002

Chitin, a $\beta$-1,4 polymer of N-acetyl-D-glucosamine, is one of the most abundant organic compounds in nature. Chitinase (EC 3.2.1.14) is an enzyme that degrades chitin to chito-oligosaccharides, diacetyl rhitobiose and N-acetyl-D-glucosamine. An extracellular chitinase-producing bacterial strain was isolated from soil and named to as Bacillus subtilis JK-56. Optimum culture condition of B. subtilis JK-56 for the production of chitinase was 1% chitin, 0.5% polypepton, 0.1% KCl, 0.05% MnS $O_4$.4$H_2O$, 37$^{\circ}C$, initial pH 7.0 and 40 hour culture time. When B. subtilis JK-56 was grown in the optimum medium, one major active band and two minor active bands were detected by native-PAGE and active staining of the gel. Among them, the major band was purified from the culture supernatant by 70% ammonium sulfate precipitation and native-PAGE with BIO-RAD Model 491 Prep-Cell and named as Chi-56A. Its molecular weight was estimated to be 53kDa monomer and the isoelectric point (pI) was pH 4.3. The pH and temperature for the optimum activity of Chi-56A were pH 6.0 and $65^{\circ}C$, respectively. Chi-56A was stable up to $65^{\circ}C$ and in alkaline region. Its $K_{m}$ value for colloidal chitin was 17.33g/L. HPLC analysis of the reaction products confirmed that Chi-56A was an exo type chitinase.e.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.126-132
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• 2016

This study numerically investigates the characteristics of chemical reactions and thermal deformation in a steam reformer. These phenomena are significantly affected by the high-temperature burner gas and the process gas conditions. Because the high temperature of the burner gas ranges from 800 to 1000 K, the reformer tubes undergo substantial thermal deformation, eventually resulting in structural failure. Thus, it is necessary to understand the characteristics of the reaction and thermal deformation under the operating conditions to evaluate the reformer tubes for sustainable, stable operation. Extensive numerical simulations were carried out using commercial CFD code (ANSYS FLUENT/MECHANICA Ver. 13.0) while considering three-dimensional turbulent flows and combined heat transfer including conduction, convection, and radiation. Structural analysis considering conjugated heat transfer between solid tubes and fluid flows was conducted using the Fluid-Solid Interaction (FSI) method. The results show that when the injection temperature of the process gas and burner gas decreased, the hydrogen production rate decreased significantly, and thermal deformation decreased by at least 15 to 20%.

• Current Research on Agriculture and Life Sciences
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• v.16
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• pp.45-54
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• 1998

A thermotolerant bacterium, Streptomyces thermocyaneoviolaceus which produced xylan-degrading enzymes, utilized excellently xylan of wheat bran by producing the enzymes in comparison with that of birchwood or oat spelts. Optimal enzyme production was achieved in WB medium containing 0.8% wheat bran, 0.06% yeast extract, 0.06% bactopeptone, 0.05% $MgSO_4{\cdot}7H_2O$, 0.05% $FeSO_4{\cdot}7H_2O$, 0.05% $KH_2PO_4$ and, 0.2% $K_2HPO_4$(pH 7.0) at $50^{\circ}C$ for 24 hrs. The optimal pH and temperature for the hydrolysis of xylan were pH 5.5 and $65^{\circ}C$, respectively. The enzyme activity was retained more than 80% at the range from pH 4.5 to pH 9.5 at $4^{\circ}C$ for 12 hrs and 94% on the heat-treatment at $65^{\circ}C$ for 1 hr. Xylobiose, xylotriose, xylose, and other xylooligosaccharides were produced as end products from hydrolysis of birchwood xylan by the xylanase of S. thermocyaneoviolceus.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.4
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• pp.675-681
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• 1997

This study was conducted to investigate the effect of dietary protein and fiber levels on the activities of ethanol metabolizing enzymes of liver in ethanol-treated rats. Sprague-Dawley male rats were fed on diets containing two levels of protein(7, 20%/kg diet) and pectin(5, 10%/kg diet). In ethanol experiments, ethanol(25% v/v) was administered by oral intubation(5g/kg body weight) at the same time once a day Control animals received an isocaloric dose of sucrose. The rats were sacrificed after 5 weeks of feeding periods. Alcohol dehydrogenase and microsomal ethanol oxidizing system activities of hepatic tissue were increased more in ethanol-treated groups than in control groups. Increment of activities predominated in normal protein normal fiber group. Aldehyde dehydrogenase activity was decreased in ethanol-treated groups and significantly decreased in normal Protein normal fiber group. Cytochrome P-450 content was significantly increased in ethanol-treated groups and Predominated in normal protein groups. Xanthine oxidase activity was increased in ethanol-treated groups, but not significantly except normal protein normal fiber group. Glutathione content tended to increase in proportion to level of dietary protein and was higher in normal fiber groups than in high fiber groups, whereas it was decreased by ethanol treatment. Lipid Peroxide content was significantly increased in low Protein normal fiber groups.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.456-456
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• 2011

국내에서는 1999년부터 국가수자원관리종합정보시스템(WAMIS) 구축 및 운영을 통해 물관리정보화사업을 추진하고 있으며 기초정보분석 중심에서 수자원 계획 수립과 정책 결정을 지원할 수 있는 시스템으로 확대하여 대국민 수자원 정보 제공과 홍보를 활성화하려고 노력하고 있다. 하지만 지금까지 국내에서는 수자원 현황을 평가하기 위해 상수도보급율, 하천개수율 등을 이용하여 수자원의 단편적인 분야만을 평가하여 왔으며 이들 개별지표들만으로 국내 수자원 상황에 대해 국민들이 체감하는데 한계가 있어 이들 사업의 성과를 지수화하여 수자원 정책과 사업의 효과를 국민들에게 적극적으로 홍보할 필요가 있다. 이를 지원하기 위해 2007년부터 2009년까지 수자원 각 분야별 수자원계획수립 업무지원체계를 구축하였으며 수자원 현황 평가를 위해 분야별 평가지수를 개발하고 수자원 통합지수를 선정하여 중권역별로 산정한 바 있다(건설교통부, 2007; 국토해양부, 2008, 2009). 보다 합리적인 수자원 평가를 위해서는 분야별(물이용, 치수, 하천환경) 평가 지수의 공간적 범위 확대 및 세부지표를 추가 고려함으로써 과거에서부터 현재까지의 분야별 변화 패턴을 파악해야 한다. 이를 통해 수자원 관련 정책 및 사업의 성과를 평가하고 구축된 기초자료 및 분석정보를 제공해 줄 수 있는 도구의 개발이 무엇보다 중요하다고 하겠다. 따라서 본 연구에서는 기 개발된 분야별 평가지수 산정 결과와 분야별 현황과의 비교 분석을 통해 지수의 현장 적용성을 검토함으로써 기 개발된 지표의 취약점 및 한계점을 제시하였다. 보다 합리적이고 타당한 분야별 평가를 위해 세부지표를 추가로 선정하였으며 선정된 분야별 세부지표를 PSR 구성체계에 맞추어 구성하였다. 또한 분야별 현황 및 특성을 평가할 수 있는 분야별 평가지수를 개발하였으며 물이용 특성을 평가할 수 있는 지수를 '물이용안전성지수', 치수 특성을 평가할 수 있는 지수를 '홍수안전성지수', 하천환경 특성을 평가할 수 있는 지수를 '하천환경건강성지수'라 명명하였다. 또한 분야별 평가지수를 통합하여 수자원 현황을 평가하고 관리할 수 있는 수자원 통합지수인 '물만족지수'를 개발하여 제시하였다. 분야별 평가지수를 구성하는 각 세부지표의 특성을 파악하여 지표 산정 범위를 점, 선, 면으로 확대하여 제시하였으며 세분화된 공간단위별로 기초자료를 조사, 수집하여 시계열 DB를 구축하였다. 개발된 분야별 평가지수 및 물만족지수를 연도별 표준유역별로 구축된 DB를 이용하여 산정하고 비교 분석하였으며 상대적인 분야별 안전성 및 건강성을 평가하여 지수의 적용성을 검토하였다. 지표 관련 기초자료 및 분석을 통해 생성된 정보자료는 수자원정책 수립과정에서 매우 유용한 정보를 제공해 줌으로써 정책결정을 지원할 수 있고, 일반인과 관련 전문가들에게 수자원 관련 다양한 정보를 제공할 수 있다.