• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04b
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• pp.227-232
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• 1995

사출성형(Injection Molding)은 생산성이 좋으며 마무리가공을 거의 필요로 하지 않는 정형 형태( net shape)로 제조가 가능하고 복잡한 형상을 만들 수 있어 고분자 재료의 대부분이 사출성형법에 의해 성형 되고 있다. 최근들어 가볍고 강도가 매우 높은 고분자재료의 개발로 전기전자 제품은 물론 자동차, 항공기 등의 생산에 이르기까지 사출성형의 중요성은 더욱 가속화되고 있다. 본 연구에서는 복잡한 형상과 여러 형상의 캐비티를 갖는 경우에는 동시에 충진이 완료되기가 어렵다. 따라서, 다른 캐비티가 충진되고 있는 동안에 먼저 충진이 된 캐비티에서 고분자 수지는 압축을 받고있기 때문에 사출성형품의 치수정밀도를 향상시키기 위한 좀더 정확한 압력과 온도분포를 예측하기 위하여 기존 의 충진과정과 충진후과정(보압, 냉각과정)을 분리하여 해석 하는 것이 아니라 충진과정과 충진후과정을 동시에 해석할 수 있는 프로그램(program)을 만들었다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.6
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• pp.384-386
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• 2005

This research was conducted to determine the contents of sugar and starch between rice cultivar, ASD1 being with high seedling establishment under direct seeding cultivation and IR72 being with poor seedling establishment. The ASD1 rice cultivar was higher in sugar and starch contents than those of IR72 during germination. This result was proven to the previous research out­put with high seedling establishment in direct seeding condition as well.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4D
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• pp.587-592
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• 2006

The joint sealants used in the airside should resist the high temperature of the jet blast and the jet fuel oil spilled when the aircraft is maintained and filled. The material of joint sealant for the airside should be different from that for the road due to these characteristics. Three different kinds of the joint sealant materials were tested in this paper. The materials include the polysulfide, the polyurethane and the silicon. The test results show that the physical properties and the performance of the polysulfide show the high resistance to the jet blast and the jet fuel oil. When the characteristics of the airside considered, the polysulfide may apply in the both of the runway and the apron area, the polyuretane can be applied the taxiway. The use of the silicon sealant is not recommended for the airside.

• Journal of Chest Surgery
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• v.34 no.9
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• pp.704-710
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• 2001

Background: Extracorporeal circulation using pump-oxygenator is an inevitable process to keep vital sign during cardiac arrest for open heart surgery. However, the diversion of blood through nonendothelialized channels appears to stimulate inflammatory response, and leukocyte activation may lead to cardiopulmonary edema. Our study evaluated the effect of leukocyte-induced cardiopulmonary edema using three different pump-oxygenator priming solutions; non-hemic crystalloid solution ; leukocyte-depleted homologous blood; non leukocyte-depleted homologous blood in priming solutions. Material and Method: Each different priming solution was used on five dogs, and the effect of leukocyte-induced cardiopulmonary edema during cardiopulmonary bypass(CPB) was evaluated. For each dog after 2 hours of exracorporeal circulation and another 4 hours of post-pump period, the dog was sacrificed and its heart and lung tissues were obtained for measuring Wet/Dry ratio. Arterial $O_2$partial pressure(PaO$_2$) and $CO_2$partial pressure(Pa$CO_2$) were checked. For the evaluation of ventilatory function, $CO_2$partial pressure difference between arterial blood (Pa$CO_2$) and exhaled air(Et$CO_2$) was measured. Result: 1. No significant difference was seen in arterial PaO$_2$and Pa$CO_2$among groups. 2. Ventilatory function evaluated by Pa$CO_2$and Et$CO_2$showed no significant difference between non-hemic and blood-mixed priming solution (P<0.05). 3. Cardiac and lung Wet/Dry ratios were remarkedly lower in the leukocyte-depleted group. There was no significant difference between the non-hemic and blood-mixed groups. Conclusion: Based upon this result, we concluded that the leukocyte depletion from homologous blood of CPB priming solution has a beneficial effect in reducing cardiopulmonary edema compared with non leukocyte-depleted or crystalloid priming solutions.

• Transactions of Materials Processing
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• v.6 no.6
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• pp.489-499
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• 1997

The injection molding process is analyzed to get the information on the mold design parameters and the optimum process conditions for automotive plastic front fender. The gate position, runner size and cooling channel are determined by the estimation of the flow balance, packing time, uniform cooling and shrinkage and warpage in the injection molding analyses. The procedure can be used in the mold design in the early stage when developing plastic parts.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2002.05b
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• pp.289-295
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• 2002

Crab shell 충진 칼럼을 이용한 수중 중금속의 연속적 제거에 있어서 여러 중금속 ($Pb^{2+}$ , $Cd^{2+}$ , $Cu^{2+}$ , $Cr^{3+}$ )의 제거능 비교와 중금속 제거 전후의 crab shell의 표면 변화를 관찰해 보았다. Crab shell 충진 칼럼의 중금속 제거능을 알아보기 위해, 가장 변화가 많은 1,000 BVs까지의 crab shell g 당 각각 중금속의 제거량을 비교해 보면 $Pb^{2+}$(0.61 mmol/g) > $Cu^{2+}$(0.43 mmol/g) > $Cd^{2+}$(0.38 mmol/g) > $Cr^{3+}$(0.30 mmol/g) 순으로 나타났다. $Cd^{2+}$의 경우는 미세 침전보다는 내부의 화학적 침전이나 물리적 침전에 의한 제거가 더 많이 일어나고 $Pb^{2+}$의 경우는 유출되는 미세 침전량이 전체 제거량 중 26.6 %를 차지 하고 칼럼내 crab shell 표면에서도 다른 중금속들보다 월등히 많은 미세 침전물이 관찰 됨으로 $Pb^{2+}$의 경우는 중금속 제거는 화학적 침전이나 물리적 침전에 따른 미세침전에 의해 많이 이루어지고 있는 것으로 판단된다. $Cu^{2+}$와 $Cr^{3+}$의 경우, 중금속의 고유 색깔인 청색이 중금슥 제거가 끝난 후 crab shell 표면에 착색된 것을 관찰할 수 있었다. Crab shell 충진 칼럼을 이용한 수중 중금속 제거 후 중금속을 고농도로 수거하기 위한 탈착에 있어서는 초기 20 BVs 내에서 대부분의 중금속이 탈착되어 유출되는 것을 관찰 할 수 있었다.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.1
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• pp.29-36
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• 2019

This study investigated the self-healing properties of blast furnace slag cement paste sample with $Na_2SO_4$ as a blast furnace slag activator after conducting the permeability test. Self-healing properties were examined by crack filling ratio and quantification of self-healing products. The degree of self-healing was evaluated by the crack filling ratio, and the crack filling ratio was analyzed by panoramic analysis using BSE-DIP for objectivity. The average crack filling ratio showed a tendency of decreasing from the upper part of the specimen to the lower part as the average of the top part was 18%, the middle part was 7% and the bottom part was 5% on average. The maximum crack filling ratio was 44% and the minimum crack filling ratio was 3%. The residual self-healing product after the permeability test contained a large amount of Ca element and Al element derived from the blast furnace slag, and the Si element was mainly present near the crack surface. The most abundant minerals in self-healing products were about 68% C-A-H. $CaCO_3$ was about 13% and C-A-S-H was about 8%. Three minerals accounted for 90% of self-healing products. C-A-H was mainly present at a part slightly distant from the crack surface and showed an angular or acicular shape. The C-A-S-H was generated on the surface naturally connected to the existing specimen, and the $CaCO_3$ was generally observed on the surface of the specimen or the inside of the crack.

• Journal of Chest Surgery
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• v.38 no.12 s.257
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• pp.807-814
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• 2005

Background: Cardiopulmonary bypass is an essential process to maintain circulation for saving life during the cardiac surgery, But it is a process in which systemic inflammation was evoked inevitably because of the exposure of blood to foreign surface. The injuries to distal organs during the cardiopulmonary bypass were resulted from systemic inflammation and the disturbances of micro-circulations in the organs. We designed this study to research the effects of leukocyte depletion from pump-oxygenator priming solution on the systemic inflammation, and the micro-circulation of gastric mucosa that is suggested by the gastric mucosal $CO_{2}$ partial pressure and acidity. Material and Method: The dogs were divided into three groups according to the different pump-oxygenator priming solutions; non-hemic crystalloid solution; leukocyte-depleted homologous blood; and non leukocyte-depleted homo-logous blood. Each priming solution group contained five dogs. In all three groups, 2 hours of cardiopulmonary bypass, and 4 consecutive hours of general anesthesia was maintained on the mechanical ventilation. Each dog was evaluated for the gastric mucosal pH, $CO_{2}$ partial Pressure, arterial pH, $CO_{2}$ partial pressure, the exhaled air $CO_{2}$ partial pressure and the level of IL-8 on before the cardiopulmonary bypass, 1 hour after the cardiopulmonary bypass, 2 hours after the cardiopulmonary bypass, 2 hours after the restoration of normal circulation, and 4 hours after the restoration of normal circulation after the cardiopulmonary bypass. The levels of IL-8 were measured with ELISA (enzyme linked immunosorbent assay) technique. Result: 1. There were significant differences of gastric mucosal $CO_{2}$ partial pressure between the leukocyte-depleted homologous blood group and other two groups(vs non leukocyte-depleted homologous blood group; P=0.02, vs non-hemic crystalloid solution group; P=0,01). 2. The gastric mucosal pH of leukocyte-depleted homologous blood group was significantly different from non leukocyte-depleted homologous blood group (p=0.01). 3. The levels of IL-8, which examine the systemic inflammation, showed signi- ficantly better results in leukocyte-depleted homologous blood group and non-hemic crystalloid solution group than non leukocyte-depleted homologous blood group (p=0.01, 0.01). Conclusion: Based upon these results, we concluded that the leukocyte depletion from the pump-oxygenator priming solution has a beneficial effects in reducing systemic inflammation and the preserving of gastric mucosal micro-circulation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.34-37
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• 2007

Propellant filling and holding test was carried out using liquid oxygen as a working fluid. The feeding line system has a filter at propellant tank outlet. Vaporization of liquid oxygen during holding after completion of filling and effect of vaporization to recirculation performance in this system was observed. Filling rate and pressure of tank ullage had the effect on state of liquid oxygen in feeding line. There was no geysering in feeding line during holding because of the position of filter.

• 수도
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• v.23 no.6 s.81
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• pp.30-35
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• 1996

조류의 성장에 기인하여 대청호로부터 발생된 이취미와 천연유기물질의 제거를 위해 활성탄 흡착에 관한 파일롯 플랜트연구를 수행하였다. 대청호원수의 용존유기물질 농도는 1.5-3.5mg/1으로 나타났고, 이취미를 유발시킨 주 성분인 Geosmin농도는 가을에 60ng/1 이상이 검출되었다. 이는 8월말부터 발생하기 시작하여 10월말 까지 지속되었다. 이는 8월말부터 발생하기 시작하여 10월말 까지 지속되었다. 한국수자원공사 대청수도내 파일롯 플랜트는 재래식정수처리 시스템에 오존산화공정, 4개의 입상활성탄 흡착탑으로 구성되었다. 공탑체류시간(EBCT) 15분 이상에서, 이취미 발생기간동안 GAC 3지와 4지에서 이취미는 완전히 제거되었다. 활성탄 원료 종류별 DOC제거를 위한 파일롯연구에서 석탄계 활성탄으로 충진한 GAC 3지와 4지는 운전 3개월 후에 파괴되기 시작하였고, 이 후 4개월의 운전동안 약 40-50%의 일정한 제거효율을 보여주었다. 야자계 활성탄으로 충진된 GAC 2지는 2개월의 운전 후에 완전히 파괴되었다.