• 대한환경공학회지
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• 제30권7호
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• pp.683-687
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• 2008

수중에 포함된 진흙 및 흙탕물 등의 부유물질을 제거하기 위해 자연 침강방법을 이용할 경우 수처리 시간이 장시간 소요됨으로써, 거대설비가 필요할 뿐만 아니라 이에 따른 많은 인력이 동원되어야 한다는 단점을 가지고 있다. 따라서 본 연구에서는 진흙 및 흙탕물 등의 부유물질을 제거하기 위한 방법으로 자성분말체를 이용하여 황토수의 부유물질을 고속으로 제거하기 위한 조건을 확인하였다. 부유물질이 0.3%인 황토수의 부유물질을 고효율적으로 제거하기 위해서는 수중의 pH가 7.0$\sim$7.5, 마그네타이트의 자성분말체가 0.1$\sim$0.2%, 무기응집제인 황산알루미늄이 알루미늄으로서 13 ppm, 아크릴아마이드 계열의 고분자응집제 0.5 ppm의 농도를 유지함으로써, 황토수의 부유물질 제거율이 극대화되었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.1458-1465
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• 2010

A lot of dredging and reclaming projects are recently under way in Korea for the efficient use of limiting land space. Saemanguem area is special case of reclaiming by dredged soil. In case of a confined disposal of dredged soils by a pump dredger, generally coarse grained soils are separated from fines with dropping at the near part of the pump dredger. This kind of seperation of fine contents could be a factor of liquefaction by earthquake. In Korea, recently, earthquakes with magnitude of 3.0 or higher are distinctively increasing in 1990. In this study, cyclic shear characterics of Saemanguem Dredged sand depending on fine content were analyzed. A series of undrained cyclic triaxial test with cyclic stress ratio ($\sigma_d/{2\sigma_{{\upsilon}c}}'$) were performed on both isotropic consolidated specimen and sand with fine contents of 0%, 5%, 15%, 30%, 40% under the effective vertical stress of 100kPa and 50% and 60%, 70% of relative density for fine content of 0%, respectively. In the test results, cyclic shear strength increased by increasing of cyclic stress ratio($\sigma_d/{2\sigma_{{\upsilon}c}}'$) with increasing the relative density at the same number of cyclic under the effective confining pressure of 100kPa. It is almost highest the double amplitude(DA) 1%, 3%, 5%, 7.5% and 10% at fine content of 15% between Cyclic stress ratio($\sigma_d/{2\sigma_{{\upsilon}c}}'$) value at cyclic number five and fine content. Number of cyclic is 30 under the effective vertical stress of 100kPa, 70% of relative density for fine content of 15%. when the cyclic stress ratio at each relative density was compared at cyclic number five, the double amplitude(DA) 1%, 3%, 5%, 7.5% and 10%, and the pore-pressure ratio (${\Delta}u/{\sigma'}_c$) 0.95 value were compared; under the relative density of 70% and the effective confining pressure of 100kPa. The pore-pressure ratio (${\Delta}u/{\sigma'}_c$) 0.95 value showed a similar trend to the double amplitude (DA) 5% line.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2005년도 춘계학술대회 논문집
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• pp.213-221
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• 2005

광양항은 부산항과 더불어 우리나라 컨테이너 화물 처리 Two Port System의 한축으로 개발 중인 동북아 중심항만(Hub Port)으로서 향후 2011년까지 총 33개의 컨테이너 선석 등이 개발 추진 중에 있어 해상교통량이 급격히 증가하고 있으며, 또한 거대선 ${\cdot}$ 위험화물운반선 ${\cdot}$ 고속여객선의 통항이 빈번하여 대형사고의 발생우려가 상존하고 있다. 본 연구에서는 광양항을 이용하는 선박의 입출항 항로 등에 대한 해상교통환경을 면밀히 분석${\cdot}$평가하고, 통항로 및 항행보조시설 등의 적정성 검토를 통하여 미래 지향적이고 안전한 해상교통환경을 조성하기 위한 체계적이고 종합적인 항로를 설정한다.

• 한국세라믹학회지
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• 제33권11호
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• pp.1209-1216
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• 1996

MoSi2-Al2O3 composites were prepared by thermal explosion mode of self-propagating high temperature syn-thesis (SHS) using element powders of MoO3 Mo Si and Al. The combustion products of MoSi2 which have 10, 20, 30 and 40 wt% Al2O3 showed the molten state in the range of Mo to MoO3 6:1-9.5:1, 2:1-8:1, 1:1-5:1, and 1:1-3:1 (molar ratio) respectively. The combustion products which made least seperation the molten phase from the slag phase were in Mo/MoO3=9, 5:1, 8:1, 5:1 and 3:1 (molar ratio) respectively. Particles size of MoSi2 and Al2O3 in the combustion product were decreased as the molar ratio of Mo to MoO3 increase. By XRD analysis only MoSi2 and $\alpha$-Al2O3 peaks were identified in the combusion products, In case of MoSi2 containing 20wt% Al2O3 5.1wt% Al existed into MoSi2 grains and 30.7wt% Si and 7.7wt% Mo existed into Al2O3 grains. The relative density of MoSi2 containing 10, 20, 30 and 40 wt% Al2O3 were 82.7, 85.2, and 81.9% respectively. The fracture strength of MoSi2-Al2O3 composites increased with increasing Al2O3 and that of MoSi2-20wt% Al2O3 composite was 195 MPa.

• 한국식품조리과학회지
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• 제4권1호
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• pp.27-32
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• 1988

탈검제로 인산 및 초산, 구연산, 수산, 질산, 붕산 등 6종을 평지씨 기름과 대두유에 적용시킨 결과 수산을 사용하여 인산과 거의 동일한 탈검 효과를 얻을 수 있었다. 즉, 평지씨 기름에서 85% 인산 처리군과 5.10% 수산 처리군의 탄산유내의 잔류 비누물질과 인함량, 탈색유에서의 색상, 탈취유의 과산화물값, trans 지방산 함량 등은 유사한 결과를 나타내었다. 대두유에서도 동일한 결과를 얻었으므로 탈검제로서 인산 대신 수산을 사용할 수 있음을 확인하였다. 한편 85% 인산처리군과 10% 수산처리군으로부터 얻어진 폐수를 분석한 결과 특히 BOD, COD 등에서 현격한 차이를 보였으며 침전분리 및 화학처리한 결과 인산 처리군은 수산 처리군에 비하여 처리시약 요구량 및 처리시간이 각각 3배, 1.7배로 차이가 극심하였다. 따라서 이들 식물성 기름에서 인산대신 수산을 사용하여 동일한 탈검효과를 얻을 수 있었을 뿐만 아니라 폐수 처리도 개선할 수 있었다.

• 한국수산과학회지
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• 제15권3호
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• pp.199-206
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• 1982

뱀장어의 동결저장 및 해동후에 일어나는 섬유의 변화를 현미경적으로 관찰한 결과를 요약하면 다음과 같다. 1. 동결 1개월 후의 조직은 근세포내외에 수결정이 많이 생겼으며 $-40^{\circ}C$ 저장한 것은 세포내에 수결정이 생성하고, $-20^{\circ}C$로 저장한 것은 세포외에 수결정이 생겼다. 2. 해동후의 피하지방층은 저장온도에 관련없이 별 변화가 없었으나, 근육조직은 높은 온도($-20^{\circ}C$)로 저장한 것이 근세포의 복원도 불충분하고 탈수변형이 심하였다. 3. 근육파쇄편을 현미경 관찰한 결과, 동결한 것은 투명감이 소실되고, 건조한 것은 변형수축되며, 가열한 것은 수분유리 및 변형이 일어난다는 것을 알 수 있었다.

• 대한치과보철학회지
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• 제36권2호
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• pp.336-354
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• 1998

Traditionally, many kinds of mechanical bonding techniques were used for bonding resins to the surface of the metal alloys. If there is a seperation between resin and metal junction by stress accumulation and temperature change of oral cavity, the cracks or crazing may occur, accompanied by failure of resin bonding to metal. This study was designed to compare the shear bond strength of the type IV gold alloy and Cr-Co alloy surfaces treated with various methods and thermocycling. Universal Instron (Model 1000) and scanning electron microscope (JEOL, Japan) was used to record the shear bond strength of 5 groups. Forty specimens were made for each group ; group 1 was treated with sandblasting only, group 2 was coated with V-primer after sandblasting, group 3 was coated with Metal primer, group 4 wase coated with MR Bond and group 5 was coated with silane. After treated with various methods, thermocycling was done for half of the each group. The surfaces of failed pattern were observed with SEM. The results were as follows : 1. Shear bond strength of the group 1 was lower than that of another groups in type IV gold alloys and bond strength of the group 1, 2 were lower than that of group 3, 4, 5 in Cr-Co alloys. 2. Shear bond strength of the gold alloy with resin was higher than that of Cr-Co alloy when specimens were coated with V-primer. 3. Shear bond strength of the Co-Cr alloys with resin was higher than that of gold alloys when specimens were coated with Metal primer. 4. The bond strength of all specimens did not decreased significantly after thermocycling. 5. Adhesive failures were found in group 1 and Cr-Co alloy in group 2, but adhesive and cohesive failures were found in another groups.

• Current Research on Agriculture and Life Sciences
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• 제21권
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• pp.23-29
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• 2003

Worldwide consumption of vegetable soybean bas been increasing recently, hence it is necessary to produce good quality of soybean in our farms. In the process of vegetable soybean production threshing and seperation work accounts for about 80% of overall labor. Therefore, developing of the vegetable soybean thresher is necessary to reduce the cost of labor. The purpose of this study is to acquire the basic informations to design of the vegetable soybeans-thresher. We make the experimental system which measure the physical properties and investigate the detachment forces. Also, We calculated the minimum speed of threshing cylinder. The result are as follows; 1. The average length of soybean stem is 68.2cm. 2. The length of soybean pods are seen as 61.3mm for 3 grain, 52.6mm fer 2 grains and 41.0mm fer 1 grain 3. The widths of soybean pods are seen as 14.1mm fer 3 grain, 13.8mm fer 2 grains and 13.4mm fer 1 grain. 4. The weights of soybean pods are seen as 4.1grams for 3 grains, 2.7grams for 2 grains and 1.4grams for 1 grain. 5. The average detachment forces of pods are seen as 1.5kgf for 3 grains, 1.2kgf for 2 grains and 0.8kgf for 1 grain respectively For 1 grain, the detachment force of pods ranges from 0.2kgf to 1.4kgf. For 2 grains, the minimum detachment force of pods is seen as 0.6kgf and the maximum one is seen as 2.5kgf. For 3 grains, the minimum detachment force of pods is seen as 0.7kgf and the maximum one is seen as 2.7kgf. 6. The minimum speed of threshing cylinder is shown 6.83m/s.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 추계학술대회
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• pp.517-527
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• 1997

Magnetic Resonance Spectroscopic Imaging is a methodology combining the imaging and spectroscopy. It can provide the spectrum of each areas of image so that one can easily compare the spectrum of one position to another position of the image. In this study, we developed pulse sequence or the spectroscopic imaging method, RF wave forms or the saturation of water signal, computer simulations to validate our method, and confirmed the methodology with phantom experiment. Then we applied the spectroscopic method to human subject and identified a few important metabolites in in vivo. To develope a water saturating RF waveform, we used Shinnar-Le-Roux algorithm and obtained maximum phase RF waveform. With this RF pulse, it could suppress the water signal to 1:1000. The magnet is shimmed to under 1.0ppm with auto-shimming technique. The saturation bandwidth is 80Hz(2ppm). The water and fat seperation is 3.3ppm(about 140Hz at 1 Tesla magnet), the bandwidth is enough to resolve the difference. But we are more concerned about the narrow window in between the two peaks, in which the small quantity of metabolites reside. We performed the computer simulation and phantom experiments in 8*8 matrix form and showed good agreement in the image and spectrum. Finally we applied spectroscopic imaging to the brain of human subject. Only the lipid signal was shown in the periphery region which agrees with the at distribution in human head surface area. The spectrum inside the brain shows the important metabolites such as NAA, Cr/PCr, Choline. We here have shown the spectroscopic imaging which is normally done above 1.5 Tesla machine can be performed in the 1 Tesla Magnetic Resonance Imaging Unit.

• Applied Microscopy
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• 제19권2호
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• pp.99-118
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• 1989

The cardiotoxic effects of acute and chronic administration of adriamycin (ADR) were evaluated in A/J Swiss albino mice. In acute studies, male mice received intravenous ADR, 5mg or 15mg/kg per day for 3 or 1day and were sacrifice 12 hours later. Because the glutathione-glutathione peroxidase system is major pathway for free radical detoxication, glutathione levels and glutathione peroxidase activity was measured. In acute studies, ADR-treated mice exhibited significantly decreased levels(p<0.05) of total glutathione and unchanged levels of oxidized glutathione and percentage of oxidized glutathione. The earliest myocardial fine structural alterations included swelling and degeneration of mitochondria and dilatation of sarcoplasmic reticulum at all dosage of acute models. In chronic studies, mice received 5mg/kg ADR once a week for up to 16 weeks. Levels of total and reduced glutathione were decreased significantly(p<0.01) and oxidized glutathione and percentage of oxidized glutathione were increased significantly (p<0.05). Chronic myocardial lesions included perinuclear vacuolization, seperation of myofibrils and the fasciae adherens of intercalated disc and hypercontraction band within myocyte. Glutathione peroxidase activity reduced significantly (p<0.01) in any group of acute and chronic ADR-treated animals. Test for lipid peroxidation(malondialdehyde) was increased significantly(P<0.01). Thus, we conclude 1) ADR significantly lowers glutathione levels in heart tissue, and 2) cellular damage progress produced by alteration of this system in mouse models of ADR cardiotoxicity. These results suggest that the glutathione-glutathione peroxidase system may be involved in the modulation of ADR-induced cardiotoxicity.