• Journal of the korean Society of Automotive Engineers
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• v.18 no.2
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• pp.64-71
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• 1996

내연기관은 19세기에 발명되어 20세기에 이르는 약 100여년에 걸쳐 계속 발달하여, 오늘날은 육.해.공의 각종 원동기로 사용되어 인간생활에 없어서는 안될 중요한 위치를 차지하고 있다. 사용연료는 거의가 액체연료인 석유계가 대부분을 차지하고 있고, 이의 수요가 날로 증가됨으로써 석유자원의 고갈 위기와 함께 유해성 배출가스의 방출에 기인되는 환경오염의 측면에서도 매우 심각한 문제로 대두되고 있다. 따라서 종래의 석유계 연료로부터 탈피하여 값싸고 장기적으로 안정하게 고급될 수 있는 대체연료 개발과 에너지 절약기술에 대한 다각적인 연구가 전 세계적으로 확산되고 있다. 이러한 대체연료는 단순히 가격면에서 뿐만 아니라 장기적 공급이 가능해야 하고 또한 석유자원의 고갈과 비상시의 대비를 위한 관점에서도 취급되어야 할 것으로 본다. 이러한 관점에서 어유는 어류의 자원이 고갈되지 않는 한 생산이 계속 가능하므로 대체연료로서의 이용가치를 검토할 필요가 있다고 본다. 따라서, 본 해설에서는 디젤기관용 대체연료로서 가격이 싸고 공급이 비교적 용이한 정어리유(sardine oil)를 경유와 여러비율로 혼합한 경유-어유 혼합유를 정용연소기와 선박용 디젤기관에 사용하여 그 연소특성을 기존의 경유 사용시와 비교 설명하고자 한다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1999.10a
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• pp.6-6
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• 1999

액체 로켓 엔진은 추진기관 공급 시스템으로 작동이 된다. 추진기관 공급 시스템에는 유공압장치 및 각종 배관, 필요한 압력과 유량을 연소실과 가스발생기로 공급하는 시스템, 엔진의 점화 및 정지, 발사체의 사용 목적에 따라 부과되는 기능을 수행하기 위한 장비들이 포함된다. 공급시스템은 크게 가압가스를 이용하는 방법과 터보펌프를 이용하는 방법의 두 가지로 나눌 수 있다. 잘 알려진 바와 같이 일반적으로 추력이 큰 로켓엔진의 경우에는 터보 펌프식이, 추력이 크지 않은 경우에는 가압가스 방식이 이용된다. 일반적으로 가압가스 방식은 연소실 압력이 커질수록 추진제 탱크의 압력도 커지므로, 그 두께가 두꺼워져서 비효율적이 된다. 따라서 연소실 압력이 비교적 크지 않은 추력이 약 10t 내외에서 많이 사용되고, 시스템이 터보 펌프식보다 구조가 매우 간단하므로, 작동의 신뢰도는 매우 높다.

• Membrane Journal
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• v.4 no.2
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• pp.63-77
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• 1994

일반적으로 화학공정에서 적절한 조성으로 혼합하여 기체를 사용할 때는 순수하게 정제된 기체가 2종 또는 그 이상이 혼합된 기체보다 유용하게 이용된다. 또한 화학적으로 민감한 제품을 제조시 충진 기체로서도 순수한 기체가 필수적으로 이용되는 등 최근 화학공정 기술의 발달에 따라 순수하게 분리 또는 정제 된 각종 기체들이 제품 생산의 원료 및 공정상에서의 부원료로서 많이 이용되고 있어 기체 분리에 대한 필요성이 증가되고 있다. 예를 들어, 지구상의 생활을 떠받치고 있는 근원물질중의 하나인 산소는 생명체의 생명 유지 및 자연계에서 일어나고 있는 모든 현상에 어떠한 형태로든 관여하고 있으며 공기 부피의 약 5분의 1을 차지하고 있어 거의 무진장에 가깝게 존재하고 있다. 이러한 산소를 공기에서 가려내기란 그리 쉽지는 않다. 일반적으로는 대규모의 공기를 액화하고 액체공기의 분류에 의해 얻을 수 있지만 이를 위해 소요되는 에너지는 막대한 것이며, 일정한 규모의 설비와 장소가 필요하다. 본고에서는 고분자 막에 의해 기체를 분리하여 현재 각종 산업에 응용되고 있는 현황 및 향후 응용 가능성 있는 분야에 대한 개발 동향을 살펴보고자 관련 자료들에서 발췌하여 정리하였다.

• The Safety technology
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• no.190
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• pp.24-26
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• 2013

최근 화학물질 안전사고가 잇따라 발생하면서 사업장 내 안전제품을 구비하고 안전한 작업환경을 조성하려는 움직임이 확산되고 있다. (주)유민에쓰티(대표 유흥근)는 이러한 화학물질 안전사고를 예방하기 위해 불산, 염소 등의 화학약품 유출을 감지하는 센서장치를 생산하는 곳이다. 이곳은 누수감지센서를 비롯해 스팀검출센서, 옥외용 강산 검출센서, 유기성액체 검출센서 등을 개발하면서 산업안전제품시장에서 무서운 신장세를 드러내고 있다. 특히 지난 2008년에는 인쇄전자 기반의 필름형 누수감지센서를 세계 최초로 개발해 국무총리상을 수상하면서 우수한 기술력을 자랑하기도 했다. 또한 국내외 약 50여 건에 이르는 특허 획득을 통해 품질을 인증받았으며, 미국전기전자공학회(IEEE)에 소개되는 등 해외에서도 기술력을 인정받고 있다. 이처럼 (주)유민에쓰티는 끊임없는 기술 개발로 안전한 작업현장을 조성하는 데 이바지하고 있다. 하지만 유민에스티의 모든 관계자들은 사업장 내 안전이 먼저 확보됐었기에 이 같은 성장이 가능했다고 입을 모아 말한다. 제조업 특성상 안전사고 발생률이 높은데도 불구하고 2003년 설립된 이후 단 한 건의 안전사고와 산재가 발생하지 않았을 만큼 철저한 안전관리를 전개하고 있는 것이다. 안전을 바탕으로 눈부신 성장을 하고 있는 (주)유민에쓰티를 찾아가봤다.

• Korean Journal of Human Ecology
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• v.9 no.4
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• pp.75-81
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• 2006

In this study on the recipe for Yakgwa in Jeonbuk province, a survey of the ingredients, the quantity and the recipe for Yakgwa were conducted by an interview with the notable maker of it in 9 regions ; Jeonju, Imshil, Jangsu, Jeongup, Namwon(Samaemyeon & Dukgwamyeon), Wanju, Gochang, Iksan, away from each other. The hardness testing and the sensory evaluation of Yakgwa were carried out to compare with the control group and Jeonbuk Yakgwa. The results of this study are as follows ; 1. Common ingredients of Yakgwa examined in 9 regions were flour, sesame oil or soybean oil, honey or sugar, ginger juice, alcoholic drinks and etc. The quantity of oil (sesame or soybean) per kilogram of flour was as follows between one-half and one cup of oil, between one and three cups of honey or sugar, between one-half and one cup of ginger juice and between one-half and one cup of alcoholic drinks. Making of Yakgwa in Jeonju and Imshil area, knead flour with the liquid ingredients which are mixed together before. In other areas, after sifting the mixed flour with sesame oil, and then knead the remaining with the sifted. 2. The result of the hardness testing of Yakgwa was that it is higher in this order, Iksan, Imshil, the control group, Jeongup, Jeonju. With while the difference of syrup used in each of them, the result of hardness testing in the same order shows that the component of Yakgwa has more great effect on the hardness than a kind of syrup on which the result by using syrup before&after cooking. And in the sensory evaluation, the surface color of Iksan Yakgwa was the most bright of all, and the shininess was of Imshil and the control group, the cracked level, the softness, the sweet taste and the oily taste of Jeonju Yakgwa was better than other Also, the overall preference, though less meaningful, was same result.

• Analytical Science and Technology
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• v.28 no.3
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• pp.228-235
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• 2015

The efficiency and applicability of the solid phase extraction disk method in a ²²⁶Ra analysis were examined by the gamma ray spectrometer (GRS) method using a Marinelli beaker and the liquid scintillation counter (LSC) method for groundwater. The recovered ²²⁶Ra, which was filtered by the solid phase extraction disk, was analyzed using gamma ray spectrometer The disks, which were pretreated for caulking the daughter nuclide, were sealed with polyethylene film. Distilled water was used for the blank value of the ²²⁶Ra activity. The recovery values of ²¹⁴Bi and ²¹⁴Pb in the solid phase extraction disk, which used ²²⁶Ra standard material, were 80% (295.21 Kev) and 104% (351.92 Kev), respectively, which were higher than 75% determined by the LSC. The injection of nitrogen gas into the measuring chamber reduced the interference values by about 10%. The detection limits of the ²²⁶Ra activity in a blank sample of 5 L were 0.17~0.40 pCi/L after 80,000 seconds of measuring time. The relationship of the ²²⁶Ra activity in the solid phase extraction disk method and in the LSC method in seven groundwater samples showed a correlation coefficient value 0.987, which implies the applicability of the solid phase extraction disk method. The results showed that ²²⁶Ra activity in groundwater using the solid phase extraction disk method has the following benefits: simple pretreatment, time saving, high recovery values, a low detection limit, and so on. Compared with the LSC method and the GRS method using the Marinelli beaker for the ²²⁶Ra analysis, the solid phase extraction disk method could be useful in groundwater samples with low levels of activities of radionuclides because the method is not restricted by the volume of the sample.

• Korean Journal of Weed Science
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• v.30 no.3
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• pp.233-242
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• 2010

This study was conducted to know that if ionic liquids can be applicable as control agents of harmful algae in water-ecosystem and to find out problems caused by ionic liquid application. Firstly, the differential selectivity of various fresh-water algal species to several 1-alkyl-3-methylimidazolium chloride ionic liquids was investigated. There was a distinct differential response between alkyl chain lengths from butyl to dodecyl and towards the algal organisms : Generally algicidal activity was increased with increase of chain length and among the algae used in this study, Stephanodiscus hantzschii f. tenuis, Oscillatoria tenuis and Spirulina pratensis were most sensitive to 1-dodecyl-3-methylimidazolium chloride (MAIC12), next was Microcystis aeruginosa, and the others were relatively less sensitive to the chemical. The selectivity degree was about ten to twenty times based on the $EC_{80}$ (Effective concentration required for 80% growth inhibition). Secondly, an activity persistence of ionic liquids was investigated in natural mimic condition (using water bottle containing soil-sediments under the greenhouse condition). At the application of $1.0{\mu}g\;mL^{-1}$ of 1-octyl-3-methylimidazolium chloride (MAIC8), the algal growth did not occur at all until 6 days after treatment(DAT) and observed a only little growth at 9 DAT. But the algae grew rapidly after 9 DAT. So at 20 DAT, total chlorophylls was $264.4{\mu}g\;L^{-1}$ and the growth was inhibited by 58.2% compared to untreatment. On the other hand, MAIC12 also had a similar persistence pattern to MAIC8, showing nearly 5 times more activity than MAIC8. At 20 days after $0.2{\mu}g\;mL^{-1}$ application of MAIC12, that is, total chlorophylls was $251.2{\mu}g\;L^{-1}$ and the growth was inhibited by 55.2% compared to untreatment. In summary, 1-alkyl-3-methylimidazolium chloride ionic liquids is likely to be applicable for selective control of harmful algae as potent compounds having long lasting activity. However, the difficulty of degradation seems to be a limiting factor in an eco-friendly application of the compounds.

• Journal of the Korean Society of Propulsion Engineers
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• v.2 no.2
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• pp.83-87
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• 1998

To reduce the supersonic jet noise from the liquid rocket engine, water injetion silencers were designed and tested. Test variables were the mass flow rate of water jet, the length of primary pipe and the diameter of expansion pipe. Followings are the results of this study. 1. From the same mass flow rate of water, longer primary pipe was more effective to reduce the noise. 2. Noise level was significantly reduced with increasingly water flow rate. 3. The optimum water flow rate was 10～12 times of the propellant flow rate. 4. By installing expansion pipe, noise level was reduced approximately 30㏈ compared to without expansion pipe

• Journal of the Microelectronics and Packaging Society
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• v.22 no.4
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• pp.31-36
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• 2015

The demand for multi-functionality, high density, high performance, and miniaturization of IC devices has caused the technology paradigm shift for electronic packaging. So, thermal management of new packaged chips becomes a bottleneck for the performance of next generation devices. Among various thermal solutions such as heat sink, heat spreader, TIM, thermoelectric cooler, etc. on-chip liquid cooling module was investigated in this study. Micro-channel was fabricated on Si wafer using a deep reactive ion etching, and 3 different micro-channel designs (straight MC, serpentine MC, zigzag MC) were formed to evalute the effectiveness of liquid cooling. At the heating temperature of $200^{\circ}C$ and coolant flow rate of 150ml/min, straight MC showed the high temperature differential of ${\sim}44^{\circ}C$ after liquid cooling. The shape of liquid flowing through micro-channel was observed by fluorescence microscope, and the temperarue differential of liquid cooling module was measuremd by IR microscope.

• Applied Chemistry for Engineering
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• v.7 no.5
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• pp.985-991
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• 1996

In chromatographic separation, HETP(height equivalent to a theoretical plate) is a useful quanititive parameter and it is wildely designated as column efficiency. The effects of operating conditions (sample concentration, injection volume, flow rate and mobile phase composition) on HETP were investigated in perparative liquid chromatography (PLC). Water and organic modifier of methanol were used as mobile phase. The sample of thymidine was injected into preparative C18 columns. The system was run by a isocratic mode in 1.5~5.5ml/min. The larger amounts of sample and higher flow rates of mobile phase increased HETP, which means that column efficiencies were worse. As the weight of sample injected into a chromatographic system could be prepared with different concentrations and injection volumes, for the same amount of sample, HETP was approximately increased two times with the ten-fold injection volume. HETP was mainly affected by the resistance of stationary and mobile phase mass transfer in the intraparticle section of packings at higher velocities.