• Journal of the Korean Applied Science and Technology
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• v.31 no.4
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• pp.541-548
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• 2014

This study was performed to obtain high conversion efficiency of $C_7H_8$ using non-thermal plasma and metal-supported catalyst. Adsorption-desorption characteristics of toluene was performed using 4A type (Zeolite) filled in a concentration reactor. Through this test, it was found that the concentration reactor has 0.020 g/g of adsorption capacity (at ambient temperature and pressure) and 3,600 ppm of desorption property at $150^{\circ}C$ (with in 20 min). In case of developed catalyst, toluene decomposition rate of Pd-AO (Pd coated catalyst) was better than Pd/Cu-AO and Pd/Ag-AO (Pd/Ag composite metal catalyst). Developed non-thermal plasma system was obtained flame amplification effect using injection process of desorbed tolune, and 98% of removal efficiency.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.1
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• pp.74-81
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• 2002

Combustion phenomena in a sub-millimeter scale combustor have been investigated. To evaluate scale effect on flame propagation characteristics, a cylindrical combustion chamber with variable depth was built in-house. The combustor was charged with premixed gas of hydrogen and air and ignited electronically. A piezo electric pressure transducer recorded transient pressure after the ignition. Measurements were made at different test conditions specified with chamber depth and initial pressure as parameters. Visual observation was made through a quartz glass window on top side of the combustion chamber using high speed digital video camera. From the pressure data, available work was estimated and compared with energy input required for stable ignition. The preliminary results suggested that the net thermal energy release is sufficient to generate power and enables a combustor of the size in the present study to be used as the energy source of a micro power devices .

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.12
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• pp.1793-1801
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• 2001

A study of low NOx atomizer was carried out to reduce nitrogen oxides(NOx) in a liquid fuel burner flame. The basic concept of NOx reduction in this atomizer is the fuel 2-staging combustion which is generated by a single atomizer forming two different stoichiometric flames. Two orifices swirl atomizer was selected and modified to realize this concept, and it was tested to obtain the design process of low NOx atomizer. These experiments were achieved to find out the relationship between the injection pressures and the flow rate, spray angle and drop size of swirl atomizer as well as to confirm the NOx reduction concept in real plant(power boiler). In comparison between experimental and theoretical results, the correct discharge coefficient and spray angle were obtained. In real burning test, NOx reduction rate was reached to above 27% of the case using conventional swirl atomizer.

• Aerospace Engineering and Technology
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• v.3 no.1
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• pp.188-196
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• 2004

To optimize and limit the axial length of baffle in KSR-III engine, stability rating tests using pulse gun as one of artificial disturbance devices have been done. Decay time and other parameters for the evaluation of stabilization ability of engine to external perturbation have been analyzed to quantify stabilization capacity of engine, in other words, dynamic stability margin. If baffle does not cover flame zone enough which can be considered as collision region of injector, it wasn't be able to suppress external perturbation sufficiently. The limit of combustion stability margin of engine is assumed to be 50 mm length baffle.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.541-547
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• 2010

This document presents the research and result about localization of the fiber-based launching canister of rolling missile which has helical rails. This document is about the technical process development which is included with the manufacturing of helical rails and application of the flame spaying which is different with other the fiber-based launching canister in korea. and And this document is about quality Assurance procedure through the qualification test and structural evaluation in conditions that the canister has to have in real shipboard environment.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.125-130
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• 2004

Experimental study on combustion characteristics of double swirl coaxial injectors has been conducted for the assessment of critical injector design parameters. A reusable, unielement thrust chamber has been fabricated with a water-cooled copper nozzle. Two principle design parameters, a swirl angle and a recess length, have been investigated through hot firing tests for the understanding of their effects on high pressure combustion. Clearly, both parameters considerably affect the combustion efficiency, dynamics and hydraulic characteristics of an injector. Internal mixing of propellants in a recess region increases combustion efficiency along with the increase of a pressure drop required for flowing the same amount of mass flow rates. It is concluded that pressure buildup due to flame can be released by the increase of LOx flow axial momentum or the reduction of a recess length. Dynamic pressure measurements of the thrust chamber show varied dynamic behaviors depending on injector configurations.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.376-379
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• 2004

The purpose of this work is to develop an effective active control system for combustion instabilities of premixed combustors. For the first step, the natural modes of combustion oscillation were investigated for a methane-air premixed combustor and the controls by secondary fuel injection were examined. The main premixed flame is stabilized by a swirler with orifices for secondary injection installed on the central hub. For sensing purposes, a pressure transducer and a chemiluminescence sensor were placed on the appropriate positions. The acoustic characteristics and the source of the oscillation were analyzed by those signals. To test the controllability, two methods of actuations by secondary fuel injection were examined. One is the open loop control and the other is the closed loop control. The comparison of the reduction levels of p $_{rms}$ shows that the closed loop control with a phase-shift injection performs best in this condition.ition.n.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.251-254
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• 2001

In this paper, we analysed the properties change of electric wire when the thermal stress was applied to NFR-8 and FR-PVC [600] wire. Measurement is made of the attenuation of a light beam by smoke accumulating with in a closed chamber due to nonflamining pyrolytic decomposition and flaming combustion. Results are expressed in terms of specific optical density which is derived from a geometrical factor and the measured optical density a measurement characteristic of the concentration of smoke. Referenced documents were ASTM E662 standard test method for specific Ds generated by solid materials. The furnace control system shall maintain the required irradiance level under steady-state condition with the chamber door closed of 2.5${\pm}$0.04[w/$\textrm{cm}^2$] for 20 min. According to the results of the smoke density analysis of NFR-8 and FR-PVC the highest decomposition flaming smoke density range of NFR-8 and FR-PVC were 7.2 to 77.5 and 51.1 respectively. Nonflaming smoke density range of NFR-8 and FR-PVC were 100.4 to 112.2 and 126.5 to 398.8. The amount of carbon monoxide generated was found to be much higher in FR-PVC decomposition than in NFR-8 due to incomp1ete combustion of FR-PVC which has high content of carbon in compound.

• Journal of the Korean Society of Clothing and Textiles
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• v.6 no.2
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• pp.25-32
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• 1982

본 연구의 목적은 1. 방염 가공된 의류에 대한 소비자들의 인식도를 측정하고 2. 방염 관계 법규를 확대하여 12세 이상의 어린이나 기타 연령층에서도 방염 가공된 의류를 원하는지를 알아보고 3. 인산염계 방염 가공제 사용 금지 조치가 방염 가공 의류에 대한 소비자들의 기호도에 영향을 미쳤는지 알아보기로 하였다. Alabama, Tuscaloosa 시에 있는 국민학교와 유아원에 다니는 어린이의 학부모 230명에게 1979년 9월 26일 질문지를 배부하여 그 후 3일부터 10일까지 질문지를 회수여하 83장의 유효한 자료를 얻었다. 83명의 학부모를 Group 1: 유아원에 다니는 어린이의 부모 45명 Group 2: 국민학교에 다니는 어린이의 부모 38명으로 나누고, 두 Group의 각 목적에 대한 유의도를 알아보기 위하여 Cattell,s Profile Analysis를 하였다. 목적 1과 2에 대하여서는 Group 간의 유의도가 발견되지 않았으며 목적3에 대하여서는 Group 간의 유의도가 발견되었다. 목적 3의 각 항목에 대하여 t-tests를 행하였다. 결과에 의하면 응답자들은 1. 방염 가공된 잠옷이 시장에서 널리 팔리고 있음은 알고 있으나 방염가공에 관련된 관계법규에 대하여 완전히 이해하지 못하고 있었으며 2. 방염 가공에 관련된 법규를 확대하여 어린이나 노인층의 의복이 방염 가공되기를 원하고 있으며, 3. 시장에서 방염 가공된 의류와 방염 가공되지 않은 의류가 함께 진열되어서 선택할 수 있는 계기를 원하고 있으며, 4. 유아의 부모들이 국민학생의 부모보다 방염 가공의 해독성에 대한 정확한 지식을 갖고 있었다. 그러나 이들 모두가 인산염계 방염 가공제의 독성에 대한 정확한 지식은 없었다.

• 한국연소학회:학술대회논문집
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• 2013.06a
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• pp.109-110
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• 2013

This paper describes gas turbine combustion characteristics of synthetic natural gas which contains a small amount hydrogen content. By conducting ambient pressure high temperature combustion test at gas turbine relevant combustor geometry, the combustion characteristics such as combustion instability, NOx and CO emission, temperatures at turbine inlet, nozzle and dump plane, and flame structure from high speed OH chemiluminescence images were investigated when changing hydrogen content from zero to 5%. From the results, qualitative and quantitative relationships are derived between key aspects of combustion performance, notably NOx/CO emission and combustion instability. Natural gas containing hydrogen up to 5% does not show significant difference in view of all combustion characteristics except combustion instability. Only up to 1% hydrogen addition could not change the pressure fluctuation and phase gas between fluctuations of pressure and heat release. From the results, it can be concluded that synthetic national gas which contains 1% of hydrogen can be guaranteed for the stable and reliable operation of natural gas firing gas turbine.