• 한국건설순환자원학회지
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• 제16권4호
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• pp.44-49
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• 2021

• 청정기술
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• 제13권1호
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• pp.34-45
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• 2007

고지혈증 치료제로 잘 알려져 있는 난용성 약물인 심바스타틴(simvastatin)을 대상으로 디클로로메탄을 용매로 사용하고 초임계 이산화탄소를 역용매로 사용하는 초임계 역용매 재결정법에 의해 약물 미세입자를 제조할 때, 운전 조건을 설정하는데 활용될 수 있는 가이드 라인을 제공하기 위하여 simvastatin/디클로로메탄/초임계 이산화탄소 3성분계 혼합물의 상거동을 연구하였다. 가변부피 투시 셀이 장착된 고압 상평형 장치를 사용하여 여러 가지 조건에서 3성분계 혼합물의 구름점(cloud point)을 측정함으로서 디클로로메탄과 초임계 이산화탄소의 혼합용매에서 simvastatin의 용해도를 온도, 압력, 용매 조성의 함수로 결정하였다. 주어진 온도에서 Simvastatin 약물의 용해도는 디클로로메탄의 조성과 압력이 증가할수록 온도가 감소할수록 증가하였다. 상거동 데이터를 바탕으로 교반기가 설치된 실린더 모양의 고압 용기에서 초임계 역용매 재결정 공정을 이용하여 simvastatin 약물을 미세입자로 제조하는 연구를 수행하였다. 운전 조건인 압력 ($8{\sim}12\;MPa$), 온도(303.15 K, 313.15 K), 이산화탄소 공급 속도, 교반 속도 (최대 3,000 rpm)를 변화시키면서 simvastatin 미세입자를 제조함으로써 재결정되는 약물 입자의 크기와 모양에 미치는 공정 변수들의 영향을 관찰하였다.

• 대한수학회논문집
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• 제16권1호
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• pp.137-152
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• 2001

Steady two-dimensional flows due to an applied pressure distribution in water of finite depth are considered. Gravity is included in the dynamic boundary condition. Gravity is included in the dynamic boundary condition. The problem is solved numerically by using the boundary integral equation technique. It is shown that, for both supercritical and subcritical flows, solutions depend on three parameters: (i) the Froude number, (ii) the magnitude of applied pressure distribution, and (iii) the span length of pressure distribution. For supercritical flows, there exist up to two solutions corresponding to the same value of Froude number for positive pressures and a unique solution for negative pressures. For subcritical flows, there are solutions with waves behind the applied pressure distribution. As the Froude number decreases, these waves when the Froude numbers approach the critical values.

• Biotechnology and Bioprocess Engineering:BBE
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• 제6권6호
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• pp.433-437
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• 2001

The extraction of panaxynol and panaxydol from Korean ginseng was found to be op-timal at 55$^{\circ}C$ for the shaking method, 80$^{\circ}C$ for the soxhlet method, and 65$^{\circ}C$ for the supercritical extraction method. The amount of extracted panaxydol and panaxynol, and their increased over a period of 12 h with the shaking method. The soxhlet method produced an extract with the largest panaxydol/panaxynol ratio. A reduced particle size enhanced extraction, however the ration of panaxydol/panaxynol decreased. Swelling in water was found to be detrimental for the extrac-tion of panaxydol and panaxynol.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 추계학술대회
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• pp.525-528
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• 2006

아임계 및 초임계수에 의한 목질바이오매스의 당화특성을 분석하기 위하여 분해공정 동안 압력을 23MPa(물의 임계압력)로 고정하고 물의 아임계 온도$(325^{\circ}C,\;350^{\circ}C)$와 초임계 온도$(380^{\circ}C,\;400^{\circ}C,\;425^{\circ}C)$에서 현사시나무 목분을 각각 60초 동안 처리하였다. 생성된 현사시나무의 분해산물에는 액상과 고형분의 분해산물이 섞여 있었다. 각 처리조건에 따른 목질바이오매스의 분해율은 온도가 상승함에 따라 증가하였으며 초임계 온도인 $425^{\circ}C$에서 최고 83.1%의 분해율을 나타냈다. 아임계 및 초임계수에 의해서 생성된 단당류는 고성능 음이온 교환 크로바토그래프(HPAEC)를 이용하여 분석하였다. 목질바이오매스의 초임계수 분해과정에서 처리 온도가 높아지면서 단당류 수율은 증가하는 경향을 보였으며, $425^{\circ}C$에서 가장 높은 7.3%의 단당류 수율을 나타내었다. 아임계 온도 범위에서는 현사시나무의 섬유소 성분 중에서 자일란이 우선적으로 분해되어 자일로스의 생성비율이 비교적 높았으며, 처리온도가 높아지면서 셀롤로오스의 분해에 의한 글루코오스 생성율이 급격히 상승하였다. 이렇게 생성된 단당류 성분들은 고온의 반응조건하에서 열분해 반응에 의해서 더욱 분해되어 퓨란계 화합물로 변형되었다.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2003년도 가을 학술논문집
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• pp.78-82
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• 2003

국내 원전에서 증기발생기 세정 후 발생되는 Fe-EDTA 함유 폐액 처리를 위한 초임계수 산화공정 (Supercritical Water Oxidation Process), 광촉매 산화 공정 (Photocatalyst Oxidation Process) 및 DBD 상온 플라즈마 공정 (Dielectric Barrier Discharge Atmospheric Pressure Plasma Process)이 평가되었다. 초임계수 산화 공정에 의해 99.98 %이상의 EDTA 전환율을 나타내어 EDTA 처리를 위한 효과적인 반응공정임을 확인하였으나 공정의 안정성, 부식 방지대책 등이 마련되어야 할 것으로 판단된다. 광촉매산화공정으로는 10 % 정도의 낮은 EDTA전환율을 보여 세정폐액 처리 공정으로는 부적합한 것으로 나타났다. DBD를 이용한 Methylene Blue 분해 결과 저 에너지 소비율로 높은 유기물 분해 효율을 얻을 수 있었으나 실 EDTA 공정에의 적용 및 공정 규모 확장 등에 대한 향후 연구 평가가 필요한 것으로 사료된다.

• Nuclear Engineering and Technology
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• 제40권2호
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• pp.139-146
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• 2008

This paper presents two of the fuel channel designs being considered for the CANDU-SCWR, a pressure-tube type supercritical water cooled reactor. The first is an insulated pressure tube design. The pressure tube is thermally insulated from the hot coolant by a porous ceramic insulator. Each pressure tube is in direct contact with the moderator, which operates at an average temperature of about $80^{\circ}C$. The low temperature allows zirconium alloys to be used. A perforated metal liner protects the insulator from being damaged by the fuel bundles and erosion by the coolant. The coolant pressure is transmitted through the perforated metal liner and insulator and applied directly to the pressure tube. The second is a re-entrant design. The fuel channel consists of two concentric tubes, and a calandria tube that separates them from the moderator. The coolant enters between the annulus of the two concentric fuel channel tubes, then exits the fuel channel through the inner tube, where the fuel bundles reside. The outer tube bears the coolant pressure and its temperature will be the same as the coolant inlet temperature, ${\sim}350^{\circ}C$. Advantages and disadvantages of these designs and the material requirements are discussed.

• 한국군사과학기술학회지
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• 제15권4호
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• pp.475-491
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• 2012

Green Chemistry emerged at the end of 20th century, which aims the development of the technologies for the sustainable society at the molecular level. Most products we consume in everyday life are produced through chemical processes, and we often oversee the fact that huge amount of solvents are used and disposed. At the present time most solvents used in laboratories as well as industries are volatile organic compounds(VOC), which gives health and environmental problems. Therefore scientists are seeking new materials which have equivalent properties of VOCs as solvent, and at the same time gives no health and environmental problems. In this brief review, the author describes the present status of research and development activities of green solvent materials throughout research societies worldwide. At present the most attractive green solvent candidates are water, glycerol, supercritical carbon dioxide and ionic liquids. In order to give the pictures of these materials, the author tried to introduce the overall aspects of green solvents in various chemical reaction as well as catalytic roles.

• Journal of the Korean Wood Science and Technology
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• 제50권1호
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• pp.12-30
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• 2022

Many studies on plant extracts have been reported for the treatment of candidiasis caused by Candida albicans, a representative fungal infection. This study demonstrates the synergistic antifungal activity of the combination of Phellodendri Cortex and Magnoliae Cortex, previously reported to have antifungal efficacy. Considering the antifungal efficacy and the separation of the active constituents, berberine and magnolol, hot water extraction and carbon dioxide supercritical extraction were selected for Phellodendri Cortex and Magnoliae Cortex, respectively. A combination of 0.55 g/L hot water extract of Phellodendri Cortex and 0.59 g/L carbon dioxide supercritical extract of Magnoliae Cortex showed synergistic antifungal activity. The synergistic antifungal activity of 160 μM berberine and 100 μM magnolol, which are representative antifungal compounds of Phellodendri Cortex and Magnoliae Cortex, respectively, contributes to the synergistic antifungal effect of their extracts. The additive decrease in cellular ergosterol level and the increased antifungal efficacy by extracellular ergosterol suggest that disruption of the biological function of ergosterol in the cell membrane is not responsible for the synergistic antifungal activity of berberine and magnolol. Synergistic cellular release of chromosomal DNA upon mixing berberine and magnolol indicates that disruption of the cellular structure is responsible for the synergistic antifungal effect of berberine and magnolol.

• 연구논문집
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• 통권30호
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• pp.15-23
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• 2000

In this study, develop the thermal pump using water evaporation and condensation. Vapor from heating room moves up to pumping room and press the water of pumping room. Consequently water is pumped out to water tank. Then hot vapor direct contact with cold water in condensing room after pumping process. At this time, pressure of condensing room is down to-5kPa and suck in water of tank. This pump executes self ping and good durability because of no mechanical moving parts. Thermal pump is pumped cyclic so that, this pump is not used single. Therefore thermal pump of hot water boiler used to multi-stage for stable pumping rate. As the result of performance test, the developed thermal pump proves pumping action of water evaporation/condensation. And total volume flow rate is 500liter during one hour. If three thermal pump is installed parallel, this pump can use to the hot water boiler in the 300,000kcal/h class.