• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.5
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• pp.414-422
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• 1984

This research was conducted to evaluate the effect of polluted Oncheon Stream on the marine organisms in the Suyeong Bay. Water quality and 96 hr acute toxicity to the sea urchin, Hemicentrotns pulcherrimus by recirculation bioassay were examined from Feb. 20 to Apr. 15, 1984. The 96 hr $50\%$ effective concentration($EC_{50}$) on the attachment of the podia of the sea urchin was observed to occur at test concentrations between 40.0 and $51.0\%$ (v/v), and safe concentrations may be assumed to be within 4.0 and $5.1\%$. These values indicate as follows : 1. Oncheon Stream was extremely polluted by oxygen-demanding wastes and synthetic organic compounds from sewage and industrial waste water. 2. Linear alkylbenzene sulfonate(LAS) which has not been yet included in water quality standard was discharged above the TLm. 3. Unknown toxicity may be synergy among complex substances. In consideration of the relationship between COD values of Oncheon Stream and dilution water, the effect of toxicity of Oncheon Stream water reached to the area of the Suyeong Bay where the COD value was found to be 12.2 ppm.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.172.2-173
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• 2003

단백질, 탄수화물, 유지 등과 같은 생고분자를 소재로하여 제조하는 가식성 또는 생분해성 필름은 식품표면을 코팅하거나, 식품의 내부에 사용하여 식품을 외부의 충격으로부터 보호하고 식품의 저장수명을 증가시키는 동시에 수분, 기체 및 용질의 이동을 방지하는 기능을 한다. 이러한 가식성 필름의 소재 중 하나인 전분은 비교적 저가의 재료이고 기체투과를 방지하는 성질은 우수하지만, 탄력성이 적은 단점을 가지고 있다. 생고분자필름의 물리적 강도를 증진시키고 수증기의 투과성을 낮추는 방법으로 단백질과 탄수화물을 복합적으로 사용한다 본 실험에서는 분리 대두 단백질(SPI)과 옥수수 전분을 혼합하여 가식성의 생분해성 필름을 제조하고 이들의 이화학적 특성에 대해 연구하였다. SPI 필름은 SPI 5g에 증류수 100$m\ell$을 가해 glycerol 2g을 첨가해 제조하였으며, 옥수수 전분필름은 옥수수 전분 6g에 증류수 100$m\ell$을 가해 glycerol 1.2g을 첨가해 제조하였다. SPI와 옥수수 전분의 혼합필름은 SPI와 옥수수 전분의 양을 1：1 비율로 혼합하여 제조하였다. SPI 필름, 옥수수 전분 및 SPI와 옥수수 전분 용액의 혼합필름의 각각의 수증기 투과도는 7.49$\times$$10^{-11}$, 2.69$\times$$10^{-11}$, 4.24$\times$$10^{-11}$ g.m/m$^2$.s.Pa이었다. 본 실험으로 SPI의 단일재료로만 필름을 제조하였을 때보다 SPI 용액에 옥수수 전분용액을 혼합해 필름을 제조하면 탄력성을 유지하면서 수증기 투과도를 낮출 수 있다는 결과를 얻을 수 있었다.현미밥의 유리아미노산 분석 결과 필수아미노산을 포함한 다량의 아미노산이 존재하였으며 혈압강하 기능성 성분인 GABA(${\gamma}$ -amino butyric acid) 함량은 현미가 4.7 mg/100 g, 발아현미 20.8 mg/100 g이었으며, 동결건조 후 분석한 발아현미밥의 GABA 함량은 5.7 mg/100 g이었다. 발아현미밥의 관능검사 결과는 색, 윤기, 맛, 부착성, 응집성, 탄력성이 A가 유의적으로 높았으며, 외관의 경우도 A가 더 높은 평가를 받았다. 또한 전반적으로 A가 B에 비해 유의적인 차이를 나타내진 않았지만 더 나은 선호도를 나타내었다.좋게 평가되었다.＊값은 63-68사이로, a＊값은 0.13에서 -0.89사이를 b＊값은 2-5값 사이에서 변화하여 제조한 죽의 색이 옅은 황색임을 알 수 있었다. 고형분 함량, 퍼짐성과 pH에 대한 $R^2$은 각각 0.4280, 0.5433과 0.2406임을 볼 때 버섯, 당근, 대파의 비율에 따라 제조한 쇠고기 야채 쌀죽의 고형분 함량, 퍼짐성과 pH는 설정된 범위내에서 그 유의성이 인정되지 않아 큰 영향을 미치지 않음을 알 수 있었다. 관능검사 결과, 색과 향에 대한 반응표면 회귀식의 $R^2$은 각각0.6000과 0.7825이고 P-value는 각각 0.4290과 0.0942로서 5% 수준에서 유의한 상관성이 없음을 확인할 수 있었다. 맛과 점성에 대한 $R^2$은 0.8717과 0.8068이고 P-value는 각각 0.0195 (p ＜0.05)와 0.0612로서 야채의 배합비에 따라 맛에 있어서 유의확률 5%수준에서 그 유의성이 인정되었으며, 전체적인 기호도에 대한 유의성은 $R^2$이 0.8463이고 P-value는 0.034

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.485-488
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• 2008

Recycled fine aggregate has low quality because it contains large amount of old mortar. So, its usage is limited to a lower value-add, such as the roadbed material etc. Also, alkaline water occurred from treatment process of the waste concrete is becoming the cause of environmental problem. Accordingly, this study is to develop on the high quality recycled fine aggregate produced by low speed wet abraser using sulphuric. We investigated the properties of compressive strength of the mortar which was manufactured using recycled fine aggregate containing calcined gypsum produced by earlier mentioned process. Test results indicate that mortar using recycled fine aggregate containing calcined gypsum has lowest compressive strength. It seems that low compressive strength is closely associated with the expansion of the specimen by excessive formation of ettringite.

• Journal of Periodontal and Implant Science
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• v.36 no.1
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• pp.113-123
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• 2006

연구배경 IgG에 대한 $Fc{\gamma}$ 수용기는 치주병인균에 대한 숙주 반응에 있어서 중요한 역할을 하는데, 이 중 $Fc{\gamma}RIIIa$는 NK 세포, 대식세포, 단핵구, ${\gamma}{\delta}T$세포에서 발현되며, EC2 도메인에서 158 아미노산 부위의 valine (V)-phenylalanine (F)의 유전자다형성을 보인다. $Fc{\gamma}RIIIb$는 특이적으로 중성구에 발현되는데, extracellular (ECl) Ig-like 도메인 내 4개의 아미노산 치환(substitutions)에 의한 NA1-NA2 유전자다형성을 보인다. 이 연구의 목적은 한국인에서 급진성 치주염 환자와 $Fc{\gamma}III$ 수용기의 유전자다형성과의 관련성을 알아보는 것이다. 연구방법 및 재료 치주적으로 건강한 90명 (대조군, 남자 64명, 여자 26명)과 서울대학교 치과병원 지주과에 내원하여 급진성 치주염으로 진단된 환자 43명 (aggressive periodontitis patients: AgP, 남자 30명, 여자 13명)을 대상으로 하였다. 모든 실험 대상자는 임상 실험에 대해 동의 하였고, 초진 시 전자 탐침(Florida Probe(R) Co. Gainesville, FL)을 이용하여 탐침 시 치주낭 깊이 (PPD), 임상부착수준 (CAL), 치태지수(PI), 탐침 후 출혈지수 (BOP)를 측정하였다. 또한 이들의 정맥혈에서 추출한 DNA를 PCR법, 전기영동법 등을 이용하여 $Fc{\gamma}RIIIa$, $Fc{\gamma}RIIIb$의 대립 유전자의 존재여부를 확인하였다. 이를 바탕으로 $Fc{\gamma}RIII$ 복합 유전형을 확인하여 각 군 간을 비교하였다. 연구 결과 1. $Fc{\gamma}RIIIa$에 대한 유전자다형성 연구 결과 대조군과 급진성 치주염 환자 군(AgP)사이에서는 대립 유전자 분포가 서로 유의성 있는 차이를 나타내었고 (P<0.05), $Fc{\gamma}RIIIb$에서는 유의성 있는 차이를 발견할 수 없었다. (P>0.05) 2. $Fc{\gamma}RIIIa$ 158F 대립형질이 급진성 치주염 환자에서 유의성 있게 많이 발견되어졌다. (P<0.05) 결론 이 연구를 통하여 $Fc{\gamma}RIIIa$ 유전자의 분석이 한국인의 급진성 치주염에 대한 감수성의 위험요소의 표지자로 활용할 수 있을 것으로 사료되며, 향 후 더 많은 환자를 대상으로 히는 추가 연구가 필요하다고 생각된다.

• Korean Journal of Construction Engineering and Management
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• v.10 no.5
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• pp.123-134
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• 2009

Since 1970s, urethane waterproofing method is broadly used in rooftops, underground spaces, and sports stadium for its outstanding ultraviolet blockage, watertightness, and elasticity. However, development of slippage-resistance and endurance, improvement of function considering convenience and visually pleasing of users, urethane waterproofing method is necessary, since rooftops and underground spaces have slippage and external force risks. Therefore, many improved waterproofing methods are being developed and, recently, embo-thane waterproofing method, which applies embo-spray coating system, has been developed. This paper explains exposure, nonexposure, and floor-material of embo-thane waterproofing method, and then perform experimental study for comparison with urethane waterproofing method about tensile strength, coefficient of expansion, performance of bond, anti-abrasion, and slippage-resistance. In addition, the performance index was presented for the superiority of embo-thane waterproofing method compared to urethane by setting up evaluation criteria considering not only physical performance but also design side of embo-thane waterproofing method, and Value Analysis applying AHP. Also for an assessment considering uncertain result, Monte Carlo Simulation Method was used to operate reliability analysis through statistic approach method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.3 no.1
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• pp.49-57
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• 2002

The possibility of a transmission noise reduction of piezoelectric smart panels using piezoelectric shunt damping is experimentally studied. Piezoelectric smart panel is basically a plate structure on which piezoelectric patch with shunt circuits is mounted and sound absorbing materials are bonded on the surface of the structure. Sound absorbing materials can absorb the sound transmitted at mid frequency region effectively while the use of piezoelectric shunt damping can reduce the transmission at resonance frequencies of the panel structure. To be able to reduce the sound transmission at low panel resonances, piezoelectric damping using the measured electrical impedance model is adopted. Resonant shunt circuit for piezoelectric shunt damping is composed of register and inductor in series, and they are determined by maximizing the dissipated energy throughout the circuit. The transmitted noise reduction performance of smart panels is investigated using an acoustic tunnel. The tunnel is a tube with square crosses section and a loud-speaker is mounted at one side of the tube as a sound source. Panels are mounted in the middle of the tunnel and the transmitted sound pressure across panels is measured. Noise reduction performance of a smart panels possessing absorbing material and/or air gap shows a good result at mid frequency region but little effect in the resonance frequency. By enabling the piezoelectric shunt damping, noise reduction of 10dB, 8dB is achieved at the resonance frequencise as well. Piezoelectric smart panels incorporating passive method and piezoelectric shunt damping are a promising technology for noise reduction in a broadband frequency.

• Applied Microscopy
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• v.29 no.2
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• pp.149-162
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• 1999

For investigation of the activated carbon on the mouse kidney treated with Pb, the activated carbon (40 mg/kg) and Pb (30 mg/kg) were treated orally for three and six weeks, respectivelly, and observed by the electron microscope. On the glomerulus of the group with only Pb, the basal membrane thicked, projected, and the foot processes fused. On the proximal convoluted tubules, the number of microvilli were decreased and the number of vacuoles and lysosome increased on the cytoplasm. The mitochondria and endoplasmic reticulum were extended and ribosomes dropped from the ER. On the giomerulus of the group with Pb-activated carbon, the basal membrane and the foot processes were merely changed. On the proximal convoluted tubules, the shapes and number of microvilli were not changed and the number of vacuoles, microbodies, and lysosomes decreased. The shapes of mitochondria and endoplasmic reticulum observed almost similar with control group. Th at is, elongated mitochondria and attached ribosomes to endoplasmic reticulum. As result, the activated carbon has positive effect on reducing toxicity of lead in the mouse kidney in the view of electron microscope.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.9
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• pp.712-722
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• 2018

This paper conducts parametric studies on flapping wing design, one of the most important design parameters of insect-mimicking aerial vehicles. Experimental study on wing shape was done through comparison and analysis of thrust, pitching moment, power consumption, and thrust-to-power ratio. A two-axis balance and hall sensor measure force and moment, and flapping frequency, respectively. Wing configuration is biplane configuration which can develop clap and fling effect. A reference wing shape is a simplified dragonfly's wing and studies on aspect ratio and wing area were implemented. As a result, thrust, pitching moment, and power consumption tend to increase as aspect ratio and area increase. Also, it is found that the flapping mechanism was not normally operated when the main wing has an aspect ratio or area more than each certain value. Finally, the wing shape is determined by comparing thrust-to-power ratio of all wings satisfying the required minimum thrust. However, the stability is not secured due to moment generated by disaccord between thrust line and center of gravity. To cope with this, aerodynamic dampers are used at the top and bottom of the fuselage; then, indoor flight test was attempted for indirect performance verification of the parametric study of the main wing.

• Journal of Navigation and Port Research
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• v.39 no.6
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• pp.485-491
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• 2015

The technology review about risk of hypothermia of victim according to heat transfer characteristic of life raft and sea state can use accident correspondence of standing and sinking of ship. This study studied heat transfer characteristics required for the design of life raft and thermal insulation property analysis and evaluation methods. In addition, it is study for comprehend the risk of hypothermia and suggest analysis result that is experiment of thermal insulation property and body temperature property for decide of prediction the body temperature decline Thermal Analysis apply the finite element analysis method is comprehended the property of heat conductivity, convective effect of sea water and properties changes according to property of insulation material. it measure the heat flux with attach temperature sensor on body in order to comprehend the variation of body temperature with boarding a life raft experiment on a human body. This study validate results by comparing variation of temperature measured from experiment on a body with variation of temperature from finite element analysis model. Also, the criteria of hypothermia was discussed through result of finite element analysis.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.4
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• pp.18-29
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• 2013

A new precast concrete (PC) beam and column connection system using non-prestressed wire strands was recently developed. The system is composed of one unit of two-storied PC-column and PC-beams with U-shaped ends. The connection part of the column and beams is reinforced by deformed bars and non-prestressed wire strands in combination for the improvement of workability. Structural performance of this system was verified by several experimental studies. The purpose of this study is developing a design concept of the beam reinforced by deformed bars and non-prestressed wire strands in combination, in terms of the cross-sectional analysis, based on the preceded experiment. A minimum and maximum reinforcement ratio and the calculation formula for the strength of flexural member reinforced by reinforcements having different yield strengths are derived based on KBC2009. Under consideration existing research results for the application of high strength reinforcement bars, the design yield strength of the non-prestressed wire strand is suggested. An example for the cross section design, satisfying the serviceability requirements, demonstrates the applicability of the design concept developed in the study.