• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2006.06a
• /
• pp.325-326
• /
• 2006

현 화학플랜트에서 사용되고 있는 ABS 수지 응집 공정의 경우 교반기 내부의 불균일한 유동분포와 유동메커니즘의 문제점은 공정 제품의 생산성을 저하 시키는 원인으로 작용하고 있다. 그러나 우수한 성능의 산업용 교반기를 설계하기 위해선 반드시 교반성능에 영향을 미치는 다양한 내부의 유동특성의 정량적인 실험 데이터 확보가 필요하나, 3차원적 비정상 특성을 나타내는 복잡한 구조의 내부 유동특성에 관한 정량적 해석은 현재까지도 상당한 어려운 문제로 남아있다. 이에 이런 문제점을 개선하여 생산성을 향상시키기 위해서는 PIV 기법을 이용한 교반기 내부의 유동분포와 유동메커니즘을 규명하여 교반기 내부의 최적화된 유동을 형성시키는 임펠러의 형상을 개발하고자 한다.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1992.05a
• /
• pp.20-20
• /
• 1992

혈관내에서의 비정상적인 혈소판의 활성화는 혈소판 응괴 또는 혈전 형성을 초래함으로서 동맥경화증, 심근 경색증, 혈전중등의 허혈성 질환의 발현에 직접 또는 간접적인 원인으로서 주목되고 있다. 본 연구자 등은 천연물로부터 혈소판 응집억제작용 물질의 개발을 목표로 하여 한약 또는 민간약의 형태로서 관련질환에 사용되어온 식물생약 약 40종을 검색하였으며 이들중 혈소판 응집억제작용을 갖는 식물로부터 작용 물질의 분리를 계속하여 오고있다. 본 실험에서는 작약을 메타놀로 추출하고 작용을 추적하면서 용매로 분획하였으며, 작용분획인 Et0Ac fr.으로부터 methyl gallate를 분리하였다. Methyl gallate는 오가피로부터 작용성분으로서 이미 분리 보고된 protocatechuic acid 및 artifact인 ethyl protocatechuate와 구조적으로 매우 유사하여 이들 analogs 수종에 대하여 작용을 비교 검색하였다.

• Journal of Families and Better Life
• /
• v.13 no.1
• /
• pp.99-113
• /
• 1995

본 연구는 가족체계가 청소년의 적응에 미치는 영향을 알아보는데 그 목적이 있었다. 조사대상은 대구시내 중.고등학교 2학년에 재학중인 청소년 443명이었고 사용된 측정도구는 가족응집성 및 적응성 척도와 청소년의 적응 정도를 알아보기 위한 불안척도 우울척도, 자아존중감척도였다. 자료분석은 요인분석, 신뢰도분석, 다변인변량분석 및 $Scheff\'{e}의$ 사후 검증법을 적용하였다. 본 연구에서 얻어진 연구결과와 논의를 통하여 다음과 같은 결론을 얻었다. 가족체계유형에 따라 청소년의 적응정도에 차이가 있었다. 균형가족의 청소년들이 극단가족에 비해 불안과 우울을 더 적게 느끼고 자아존중감이 높아 적응을 더 잘하는 것으로 나타났다. 이것은 가족응집성과 가족적응성이라는 가족체계의 두차원이 청소년의 적응정도에 영향을 미치는 주요한 요인인 것을 나타낸다고 볼 수 있으며, 청소년이 건전하게 적응할수 있도록 하기 위해서는 가족체계가 높은 응집성과 적응성으로 기능할 것이 요구된다고 하겠다.

• Clean Technology
• /
• v.6 no.1
• /
• pp.27-38
• /
• 2000

A physicochemical process called Ultra Rapid Coagulation(URC) can dramatically remove organics, metals, and phosphates in wastewater by adding weighted coagulation additive(WCA) and recycling sludge into the coagulation basin to increase the growth rate and adsorption ability of floc. Also this process can improve floc settling rate than conventional coagulation process and reduce the pollutants loaded into the receiving water for securing water source. It was evaluated that WCA and sludge added have effects on the removal efficiency and estimated the possibilities of reusing the effluent from this process.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.42 no.11
• /
• pp.919-926
• /
• 2014

In this paper, the effect of material properties on fracture behavior was studied using cohesive zone model and extended finite element method. The rectangular tensile specimen with a central inclined initial crack was modeled by plane stress elements. In the CZM modeling, cohesive elements were inserted between every bulk elements in the predicted crack propagation region before analysis, while in the XFEM the enrichment to the elements was added as needed during analysis. The crack propagation behavior was examined for brittle and ductile materials. For thin specimen configuration, wrinkle deformation was accounted for by geometrically nonlinear post-buckling analysis and the effect of wrinkling on the crack propagation was investigated.

• The KIPS Transactions:PartD
• /
• v.12D no.7 s.103
• /
• pp.957-964
• /
• 2005

According to rapid growth of web environment, user interface design needs to support the complex interactions between human and computer. In the paper we suggest the object modeling method for Qualify Improvement of User Interface. We propose the 4 business event's object modeling phases such as business event object modeling, task object modeling, transaction object modeling, and form object modeling to enhance visual cohesion of UI. As a result, this 4 phases in this paper allows us to enhance visual cohesion of User Interface prototype. We have found that the visual cohesion of business events become strong and unskilled designer can develope the qualified user interface prototype. And it also improves understanding of business task and reduces prototype system development iteration.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.34 no.9
• /
• pp.1320-1324
• /
• 2005

Soybean (Glycine max L.) is an increasingly important food source and functional food. Platelet aggregation plays an important role in thrombogenesis and atherosclerosis. Here, we studied the anti-platelet aggregating effects of solvent extracts from Korean soybean varieties and isoflauone derivatives. Nine Korean soybean varieties were extracted by solvents (methanol and buthanol and their extracts was investigated for the inhibition against tile aggregation of washed rabbit platelets induced by collagen or thrombin. Maximal inhibition of buthanol extracts against platelet aggregation induced by collagen was $95\%$ in Black-kong and Jinpum - kong. The potency of their inhibition was in the following order : Black > Jinpum > Bokwang > Hwangkum > Pureun > Malli > Danbaek > Danyeob > Jangsu - kong. The Black - kong only seemed to produce the maximal inhibition against platelet aggregation induced by thrombin. Total isoflavone content measured was Jinpum-kong ($1347.8{\mu}g/g$) and Black-kong ($918.7{\mu}g/g$). Maximal inhibition of isoflavone derivatives against platelet aggregation induced by collagen was $97\%$ in genistein. The potency of their inhibition was in the following order: genistein>daidzein>genistin. The isoflavone derivatives did not affect the platelet aggregation induced by thrombin. However, Black-kong cortex seemed to Produce the optimal inhibition against platelet aggregation induced by collagen. These results suggest that Black-kong and Jinpum-kong may be a good source for antiplatelet agents, and their antiplatelet effect be related to tile content and the chemical structure with the number of -OH group and the attached glycoside in the isoflavone derivative.

• Journal of Korean Society of Environmental Engineers
• /
• v.22 no.7
• /
• pp.1263-1271
• /
• 2000

This study investigated the floc structure and removal of turbidity and organic matter by alum coagulation. Results of this study indicated that sweep floc and charge neutralization area were shifted to more acidic region than that in the Amirtharajah's diagram. This was caused by organic matter present in the raw water. Removal regions of turbidity and organic matter were generally overlapped. However, organic matters was removed better at lower pH than turbidity. Floc structure was characterized by measuring fractal dimension and volume diameter using AIA and SALLS. SALLS method was found to be more reliable than AIA method. Floes in sweep floc region had larger size and fractal dimension than flocs in charge neutralization region. As pollutant removal increased, larger fractal dimension and size of floc were measured.

• Korean Journal of Environmental Biology
• /
• v.19 no.2
• /
• pp.129-135
• /
• 2001

The effects of CellCaSi and bioflocculant on the control of algal bloom were investigated in enclosures in a small eutrophic pond. The bioflocculant produced by a bacterial strain S-2 was finally selected to remove Microcystis aeruginosa which was a dominant species of algal bloom in the pond. Enclosure experiment showed that phosphorus concentration decreased dramatically from $131\mu{g}\ell^{-1}$ (Control) to $1-14\mu{g}\ell^{-1}$ in three CellCaSi-enriched enclosures. Chlorophyll $-\alpha$ concentration also decreased from $215\mu{g}\ell^{-1}$ (Control) to $59\mu{g}\ell^{-1}$ by the addition of CellCaSi $(1g\ell^{-1}$, bioflocculant $(2ml\ell^{-1}$, calcium chloride $(1g\ell^{-1}$ and ferric chloride $(2mg\;Fe\ell^{-1})$ in Enclosure 4. From the results of the mouse acute toxicity test of the S-2 bioflocculant and the goldfish survival test in enclosures, it seems that both the S-2 bioflocculant and the CellCaSi do not show any severe toxicity in water system. Consequently, it was concluded that the bioflocculant and the CellCaSi could be used to control algal bloom in eutrophic waters by removing phosphorus and chlorophyll$-\alpha$.

• Journal of Korean Society of Environmental Engineers
• /
• v.28 no.1
• /
• pp.34-41
• /
• 2006

The objectives of this study were to investigate the affecting factors on streaming current(SC) and to evaluate set point(SP). For the study, a pilot scale apparatus with a capacity of 12 L/min was operated at Guui water intake of Seoul. SC was monitored with varying poly aluminium chlorides(PACs) dose and water quality parameters like conductivity, turbidity, temperature, and pH. The removal efficiencies were evaluated in terms of turbidity and dissolved organic carbon(DOC) with varying coagulation conditions. The effects of affecting factors on SC and SP were also estimated. According to the result observed from the variation of SC with water quality parameters during the experimental period, tendencies of SC and conductivity were very similar, and SC and conductivity had a strong linear relation. At the optimum condition of coagulation, SP decreased as the rainy season changed to the dry season, during the experimental period. Especially, in condition of low turbidity, conductivity had relatively more effect on SC than turbidity. As conductivity increased, SP decreased and coagulant dose per unit increase of SC gradually increased. In view of the results so far obtained, it may be possible to determine the SP range considering the real time variation of water quality, especially conductivity.