• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1999.04a
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• pp.17-17
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• 1999

충돌제트는 산업, 항공우주, 군사 분야 등 공학적으로 많은 분야에서 응용되고 있다. 산업분야에서 충돌제트는 설치가 간단하고 형태가 단순하면서도 열 및 물질 전달효과가 상당히 크기 때문에 고효율의 열전달 효과를 얻을 수 있다는 점에서 광범위하게 응용된다. 예를 들면 물체 표면의 부분냉각은 고온 금형의 급속 냉각, 가스터빈 깃의 냉각, 전자부품의 냉각 등에 이용되며 부분 가열에서는 제철, 제지 및 유리공업, 금형의 풀림 등에 폭 넓게 적용된다. 항공우주, 군사분야에서는 수직/단거리 이·착륙기(V/STOL)의 발진, 미사일 발사시스템, 다단 로켓의 분리, 우주공간에서의 도킹, 화염 편향기 등에 적용이 되며 대부분 평판이나 특수한 판의 형상에 과소 팽창제트가 충돌할 때 발생하는 현상에 대한 것이다.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05b
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• pp.324-328
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• 1997

이트리아와 RuO$_2$의 반응특성 및 반응생성물의 고온안정성 등을 DTA(Differential Thermal Analysis), TGA(Thermo-Gravimetric Analysis)를 이용하여 분석하였고 반응생성물은 XRD(X-ray diffractometry)와 XPS(K-ray photoelectron Spectroscopy), 주사 전자현미경를 이용하여 분석하였다. 이트리아와 RuO$_2$의 혼합물은 약 95$0^{\circ}C$ 이상에서 표면이 거친 $Y_2$Ru$_2$O$_{7}$를 형성하였고 생성된 $Y_2$Ru$_2$O$_{7}$은 공기분위기하에서 140$0^{\circ}C$까지 가열하여도 무게변화가 없는 안정한 물질이었다.이었다.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.147-148
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• 2020

In case of high temperature damage such as fire, the durability of concrete is reduced due to the collapse of internal pore tissue. Therefore, in this paper, we are going to analyze the pore structure of cement paste hardening agent using MIP analysis and build up 3D data produced using X-ray CT tomography. The test specimen is made of cement paste from W/C 0.4. As the temperature of heating increased, the amount of air gap and the diameter of air gap in cement paste increased. It is judged that the air gap structure inside cement collapsed due to the evaporation of the hydrate, gel count, capillary water, etc. inside the cement due to the high temperature.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.140-141
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• 2020

Concrete has a lower thermal conductivity or thermal diffusion coefficient compared to other building materials, so it is widely used as fireproof compartment material or refractory material for structures. However, in the event of thermal damage such as fire, cement curing agents and aggregates act differently, resulting in heat generation or deterioration of tissue due to dehydration, resulting in deterioration of physical properties and fire resistance. Therefore, in this study, the processing structure of cement paste is measured through nitrogen absorption method. The test specimen is a cement paste of 40% W/C and is set at 1000 ℃ under heating temperature conditions. As the temperature rose, the micro-pore mass below was reduced based on about 0.01 감소m, but the air gap above that was increased.Thus, in the range of pores measured in nitrogen adsorption, the air mass tended to decrease under high temperature conditions.

• Journal of the Korean Wood Science and Technology
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• v.36 no.6
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• pp.41-48
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• 2008

The required energy for the heat treatment of pine log was evaluated in this study. A proper heat treatment of pine log infected by pinewood nematode (Bursaphelenchus xylophilus) can prevent spreading of the infection by pinewood nematode and make the infected pinewood valuable again. The FAO (Food and Agriculture Organization of the United Nations) heat treatment standard for various types of infected wood for which a heat treatment of the core part of the wood is necessary is 30 minutes at $56^{\circ}C$, taking into account the international standards for phytosanitary measures (ISPM No. 15). In this study, the energy consumption during the heat treatment was separated into two kinds of energy, initial energy for heating kiln drier and to reach set point temperature and relative humidity and the required energy supplementing heat loss. The initial required energy per unit time is greater than that during the treatment. The energy consumption per unit time varied little during the heat treatment. As a result, the set point relative humidity with set dry bulb temperature and density of wood dependent on moisture content are very important factors to change energy consumption in the experiment. The heat treatment at higher temperature and higher humidity levels requires more energy consumption but less treatment time. It is expected that a more effective energy program could be planed for the heat treatment of pine log through this study.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.11
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• pp.1701-1708
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• 2014

Phenolic compounds, physiological properties, and digestive enzyme inhibitory effect of 70% ethanol extracts from Aster scaber with different extraction methods (stirrer extraction, SE; reflux extraction, RE; autoclave extraction, AE; low temperature high pressure extraction, LTPE; ultrasonification extraction, USE) were investigated. Total polyphenols and flavonoids contents in LTPE were significantly higher than those of other extracts. The amount of substances related to cynarin (1,3-O-dicaffeoylquinic acid) was highest in USE (34.34 mg/g), followed by LTPE (33.83 mg/g), RE (32.27 mg/g), AE (25.40 mg/g), and SE (18.17 mg/g). Chlorogenic acid (5-O-caffeoylquinic acid) and astragalin (kaempferol-3-O-glucopyranoside) were highest in AE and LTPE, respectively. Xanthine oxidase, angiotensin- I converting enzyme, 3-hydroxy-3-methylglutaryl coenzyme A reductase and acetylcholin esterase inhibitory activities of LTPE and USE at a concentration of 50 mg% (w/v) were somewhat higher than those of other extracts. The ${\alpha}$-amylase, ${\alpha}$-glucosidase, trypsin and lipase activities showed the same tendency as physiological properties (concentration of 500 mg%, w/v). Additionally, there was significantly higher or slightly lower inhibitory activity compared to the control group. These results suggest that extracts from Aster scaber have potential to act as functional materials, and LTPE and USE are superior for the enhancement of biological activity.

• Korean Journal of Food Science and Technology
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• v.48 no.6
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• pp.565-568
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• 2016

This study was conducted to soften the tough texture of retorted beef in storage by increasing the water holding capacity (WHC) after pretreatment involving soaking and blanching in a phosphate solution. The yield of pretreated beef, based on weight as an indirect indicator of WHC, soaked in 0.35% (w/w) complex phosphates for 1 h, increased by 5-10%, in contrast to the untreated control in which the rib and shank was heated at $100^{\circ}C$ for 5-40 min. Additionally, strength of mechanical toughness in the fore rump and rib after phosphate curing at $115^{\circ}C$ for 30 min and blanching at $100^{\circ}C$ for 2 min were significantly decreased to 1.3 and $1.4kg_f$ (p<0.05) as compared to 2.0 and $1.8kg_f$ in the control, respectively. During storage of retorted beef for 30 days at $10^{\circ}C$, rib and shank pretreated with 0.35% complex phosphates exhibited a highly soft texture as compared to that of untreated beef. The softening of pretreated beef was based on the increased WHC due to complex phosphates.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1754-1759
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• 2008

To produce plastic parts that have fine pattern through conventional injection molding, a lot of difficulties follow. Therefore, rapid heating and cooling methods are good candidates for manufacturing injection-molded parts with micro/nano patterns. In this study, we adopted the E-Mold patent technology. The mold for E-Mold technology has a separate heated core with micro heaters. It is very important to optimize the lay-out of the heaters in heated core because it influences both control and distribution of mold temperature. We developed a optimization method of heating line lay-out by using commercial softwares and compared the output with the experimental results. We used Pro-Engineer Wildfire 2.0 for the mold design, ICEMCFD for mesh generation, and FLUENT for heat transfer simulation. The simulation results showed the temperature profile from $60^{\circ}C$ to $120^{\circ}C$ or $180^{\circ}C$ during heating and cooling process which were compared with the injection molding experiments. We concluded that the simulation could well explain the experimental results. It was shown that the E-Mold optimization design for heater lay-out could be available through the simulation.

• Journal of Soil and Groundwater Environment
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• v.14 no.5
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• pp.62-70
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• 2009

A field soil highly contaminated with petroleum hydrocarbons (JP-8 and diesel fuels) was employed for its remediation by a lab-scale thermal desorption process. The soil was collected in the vicinity of an underground storage tank in a closed military base and its contamination level was as high as 4,476 ppm as total petroleum hydrocarbon (TPH). A lab scale directly-heated low temperature thermal desorption (LTTD) system of 10-L capacity was developed and operated for the thermal treatment of TPH contaminated soils in this study. The desired operation temperature was found to be approximately $200-300^{\circ}C$ from the thermal gravimetric analysis of the contaminated field soils. The removal efficiencies higher than 90% were achieved by the LTTD treatment at $200^{\circ}C$ for 10 min as well as at $300^{\circ}C$ for 5 min. As the water content in the soils increased and therefore they were likely to be present as lumps, the removal efficiency noticeably decreased, indicating that a pre-treatment such as field drying should be required. The analysis of physical and chemical properties of soils before and after the LTTD treatment demonstrated that no significant changes occurred during the thermal treatment, supporting no needs for additional post-treatments for the soils treated by LTTD. The results presented in this study are expected to provide useful information for the field application and verification of LTTD for the highly contaminated geo-environment.

• Korean Journal of Materials Research
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• v.4 no.8
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• pp.934-944
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• 1994

Effects of residual chloride on thermal decomposition behaviour of a-stannic acid and physical properties of $SnO_{2}$ powder were observed. The powder was fabricated by hydroxide method; $\alpha$-stannic acid was precipitated by mixing acqueous solutions of $SnCl_{4}$ and $NH_{4}$OH . The precipitate was washed with $NH_{4}NO_{3}$ solution while washing was controlled to be of three grades to modify its residual chloride content. The precipitate was dried at $1100^{\circ}C$ ~ 24h and calcined in air at $500^{\circ}C$ ~ $1100^{\circ}C$ for one hour. Thermal decomposition behaviour of $\alpha$-stannic acid was examined by a DT-TGA and a FTIR. Chemical composition and physical properties of $SnO_{2}$ powder were observed by an AES, a BET and a TEM, respectively. With a reduction in chloride content, the relative crystallite size of $SnO_{2}$ powder slightly increased by a low-temperature-calcining. However, at a high calcining temperature(T), the reverse relation occured. It was suggested that chloride ion replaces part of lattice oxygen site of a-stannic acid. Also, chloride ion on the site was suggested to retard de-hydration as well as crystalization at a low T while to promote crystal growth of $SnO_{2}$ by forming oxygen vacancy at a high T.