• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.05a
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• pp.187-192
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• 2006

The combustion performance tests of a 30 tonf-class full-scale combustion chamber performed with water as a coolant were described. The combustion chamber has chamber pressure of 53bara and propellant flow mass rate of 90kg/s. Since it was first firing test for 30tonf-class combustion chamber using channel cooling, water coolant mass flow .ate of 35kg/s and 18kg/s were performed which correspond to 110% of kerosene design volume flow rate and equivalent cooling performance of kerosene. The test results are described and the results showed that the water cooling performance of this combustion chamber is sufficient and the firing test is feasible using the kerosene as a coolant.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.5
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• pp.649-653
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• 1999

A magnetic fluid separation technology was confirmed to be very effective to remove the suspended solids (SS) from aquacultural recirculating water, In this study, the effects of operating variables on the characteristics of SS removal were investigated through the test runs using magnetite of 2 $\mu$m mean diameter as magnetic powder. Magnetic flocculation here formed by adsorbing fine magnetites on the surface of suspended solid was observed. The strength of magnet was of significance in determining the SS removal efficiency as well as the capacity of the equipment. In addition, the SS removal efficiency decreased with an increase in the superficial liquid velocity, but the effect became negligible when the mass ratio of magnetite to the suspended solids was higher than 1.0.

• Proceedings of the Korean Fiber Society Conference
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• 1998.04a
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• pp.148-151
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• 1998

대부분의 고분자 가공공정에 있어서 가공원액(고분자 액체 또는 용융물)은 선형영역을 벗어나는 큰 크기의 변형을 받으므로 기존의 선형 점탄성 이론으로는 그 공정해석이 불가능하다. 그러므로 대변형하에서 고분자 물질의 비선형 거동 해석은 실제 공정과 관련된 공학적인 관점에서 볼 때 매우 중요한 과제라고 할 수 있다. 특히 응력완화 실험은 점탄성 액체의 비선형 완화 거동을 고찰하고 지금까지 제시된 각종 구성방정식을 평가하는데 유용하다.(중략)

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1996.05a
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• pp.41-47
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• 1996

데토네이션 현상은 화학반응면이 음속 이상으로 진행하는 경우로 연소와는 다른 분야로 취급된다. 국내에서는 발파나 무기에 응용되고 있지만 이 분야의 선진국에서는 산업의 여러 분야에 적용되며 이 분야에 많은 기초연구가 행해져 왔다. 본 연구는 이러한 데토네이션 현상을 콘크리이트나 금속의 절단이나 노화된 구조물의 해체에 응용하는 것에 관한 내용으로 고체폭약에 비해 위험하여 취급이 어려운 액체 폭약을 보다 안전하고 현상변화가 자유로운 액체의 잇점을 살려 절단에 있어 최대의 효율을 내는 형상을 단지 케이스의 가공만으로 가능하므로 경제적이다.

• Proceedings of the Membrane Society of Korea Conference
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• 1996.03a
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• pp.1-23
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• 1996

투과증발(Pervaporation)이란 어원적으로 "permeation"과 "evaporation"의 합성어인데 액체혼합물이 치밀한 비다공질막을 통해 이동하는 동안 증기화되면서 분리되는 막분리 공정이다. 이 공정에서 막 한쪽면은 액체공급액과 접하고 있고 다른 한쪽면은 낮은 투과물의 증기압과 접하고 있는데 낮은 증기압은 진공(vacuum pervaporation)을 가하거나 혹은 불활성의 담체가스(sweep gas pervaporation)를 흐르게 하므로써 얻을 수 있다. 이때 막 내부에 트과증발막공정의 추진력인 화학 포텐셜(chemical potential) 구배가 발생하여 막을 통한 물질투과가 이루어지는데 각 투과성분의 투과속도는 투과성분과 막재료간의 물리화학적 인력에 의해 결정된다.의 물리화학적 인력에 의해 결정된다.

• Nuclear industry
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• v.4 no.5 s.21
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• pp.32-41
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• 1984

현재 발전용 원자로의 $80\%$를 점하고 있는 경수로는 노심내의 핵연료에서 발생한 열을 물을 사용하여 노외로 보내는(수냉각)형식이기 때문에 열제거 효율상 물을 가압해서 고온에서도 액체로 사용하도록 고안되었으므로 노심용기는 압력용기(PV)로 되어 있다. 이 압력용기는 핵연료체와 같이 교환할 수 있는 소모품이 아니기 때문에 그 발전로의 정년까지 건전성을 유지하여야 한다. 다음은 이의 확보를 위해 해외에서 연구검토되고 있는 대응책들이다.

• Journal of the Korean Chemical Society
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• v.33 no.1
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• pp.46-54
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• 1989

The extraction method and quantitative analysis for the fat-soluble vitamins present in food stuffs and vitamin products have been investigated. The simultaneous separation and analysis of the vitamins by reverse phase high performance liquid chromatographic method was conducted using an isocratic elution with methanol : water (95 : 5) eluent on a Novapak $C_{18}$ column. The detection of vitamins was achieved by a variable wavelength UV detector. To improve the detection sensitivity detection wavelengths were set at the highest absorption bands such as 330, 265, 285, and 290nm for the respective vitamins. The analysis for the fat-soluble vitamins was finished within 40 minutes. Alkaline hydrolysis and enzymatic hydrolysis were investigated for the sample preparation; and liquid-liquid extraction and liquid-solid extraction were attempted for the extraction of vitamins. Both hydrolysis methods were turned out to be appropriate for the analysis for vitamins A, D, and E, while for the analysis of vitamin K the enzymatic hydrolysis method demonstrated better results. Diethyl ether, pentane, and n-hexane were found to give higher recovery for the liquid-liquid extraction and silica cartridge for the liquid-solid extraction.

• Journal of the Korean Vacuum Society
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• v.20 no.2
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• pp.146-154
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• 2011

The adhesive-tape of a liquid leak film sensor including the alarm system is developed. The sensing film is composed of three layers such as base film layer, conductive line layer, and protection film layer. The thickness of film is 300~500 um, the width is 3.55 cm, and the unit length is 200 m. On the conductive line layer, three conducting lines and one resistive line are formulated by the electronic printing method with a conducting ink of silver-nano size. When a liquid leaks for the electricity to be conducted between the conductive line and the resistive line, the position of leakage is monitored by measuring the voltage varied according to the change of resistance between two lines. The error range of sensing position of 200 m film sensor is ${\pm}1m$.

• Journal of the Korea Computer Graphics Society
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• v.25 no.1
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• pp.13-22
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• 2019

In this paper, we propose a new method to improve the details of the fluid surface by removing liquid sheets that are over-preserved in particle-based water simulation. A variety of anisotropic approaches have been proposed to address the surface noise problem, one of the chronic problems in particle-based fluid simulation. However, a method of stably expressing the preservation and breakup of the liquid sheet has not been proposed. We propose a new framework that can dynamically add and remove the water particles based on anisotropic kernel and density to simultaneously represent two features of liquid sheet preservation and breakup in particle-based fluid simulations. The proposed technique well represented the characteristics of a fluid sheet that was breakup by removing the excessively preserved liquid sheet in a particle-based fluid simulation approach. As a result, the quality of the liquid sheet was improved without noise.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.8
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• pp.793-799
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• 2015

In this research, we study the propagation of longitudinal and transverse waves through a metal rod including a liquid layer using computational and experimental analyses. The propagation characteristics of longitudinal and transverse waves obtained by the computational and experimental analyses were consistent with the wave propagation theory for both cases, that is, the homogeneous metal rod and the metal rod including a liquid layer. The fluid-structure interaction modeling technique developed for the computational wave propagation analysis in this research can be applied to the more complex structures including solid-liquid interfaces.