• Journal of the Korean Society of Propulsion Engineers
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• v.3 no.2
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• pp.48-55
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• 1999

Performance analysis of a 50KW turbo-generator gas turbine engine with a recuperator was studied. Recuperated cycle has been employed to meet maximum fuel economy and ultra low emissions especially for military and vehicular engines. From thermodynamic stand point, it is known that recuperative cycle can contribute most to enhance thermal cycle efficiency for the Pressure ratios under 10 and of comparatively low turbine inlet temperature. Efficiency of a simple cycle with a recuperator increases relatively about 30% than without one at effectiveness of 0.5. Pressure losses in the heat exchanger less than 5.2% is considered in the design process. A tubular type heat exchanger is selected for this particular engine because it can provide simple construction as well as structural sturdiness and excellent leak tightness.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.222-222
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• 2012

최근 반도체 시장의 300 mm/450 mm wafer 급 이상의 첨단공정에서는 진공 펌프의 대용량화 및 에너지 절감을 위한 저소비 전력화 요구와 함께 공정 중 진공 펌프의 성능저하 및 이상 징후 발생 감지 혹은 예지 요구 및 예지 보수 기술이 높아지고 있는 추세이다. 이에 현재 경험에 의존하던 진공 펌프의 predictive and preventative maintenance (PPM) 주기 설정 기술이 매우 필요함을 알 수 있다. 본 연구에서는 지식경제부에서 지원하는 산업원천기술개발사업에 참여기관으로 수행하면서 한국표준과학연구원에서 주관기관으로 진행하는 스마트형 진공 배기 진단 제어 시스템 개발 과제를 통해 (유)우성진공에서 자체 개발하는 저진공 펌프에 적용 예정중인 smart형 PMS에 대해 소개하고자 한다. 진공 환경을 조성하는 핵심장치인 진공 펌프 상태는 진공 공정 환경 조성에 가장 주요한 변수이므로 이에 따른 상태 진단 기술은 진공 공정 제어 정밀도와 공정 신뢰성 확보에 필수적이며, (유)우성진공에서 자체 개발하는 드라이펌프 및 스크류펌프 등 저진공 펌프의 정밀한 실시간 상태진단을 통해 예지 보수 기술 및 신뢰성을 확보하고자 한다.

• Journal of the Korea Convergence Society
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• v.10 no.7
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• pp.281-287
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• 2019

Application of heat recovery system applying air supply and cexhaust ventilation device essential in energy management system for the optimum ventilation system utilization and energy saving. This is a key element of infrastructure technology for high-efficiency energy buildings, because it can save heating and cooling energy in winter and summer. In this paper, heat transfer efficiency was simulated using paper, plastic, and aluminum materials that was examined to compare heat exchanger performance under uniform flow conditions. We tested heat transfer efficiengy according to the shape of two of that, one is orthogonal and the other is refraction shape. Based on the simulation results, it is expected to contribute to the production of high performance heat exchanger with heat transfer performance and pressure loss.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.2
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• pp.211-216
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• 2012

The availability of thermal energy has been widely recognized recently, and the cascade usage of thermal energy from combustion has been encouraged. Within this framework, a 1-kW-class Stirling-engine.based cogeneration system has been proposed as a unit of a distributed energy system. The capacity has been designed to be adequate for domestic usage, which requires high compactness as well as low emissions and noise. To develop a highly efficient system satisfying these requirements, a premixed slot-type short-flame burner has been proposed, and a series of experiments has been performed to understand its combustion characteristics. Flame images have been captured to observe the dependence of the flame mode on the combustion load and air/fuel ratio. The exhaust gas has been sampled and analyzed to study the emission characteristics for each flame mode.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.626-631
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• 2019

The policy-making and technological development for the supply expansion of eco-friendly automobiles has been continuing, but the internal combustion engines still accounts for about 95%. Also, in order to meet the stricter emission regulations of internal combustion engines based on fossil fuels, the proportion of after-treatments for vehicles and (ocean going) vessels is gradually increasing. This study is a basic study for the post-Euro-VI exhaust response of CNG buses, and it is to investigate the basic characteristics according to Pd substitution transition metal effect, catalyst volume effect and space velocity. A catalysts was prepared and tested using a model gas reactor. The NGOC catalyst with 3Pd exhibited the highest catalytic activity with 22% at $300^{\circ}C$, 48% at $350^{\circ}C$ and about 75% at $500^{\circ}C$. 3Co NGOC containing 3wt% of transition metal was excellent in oxidation ability, and it was small in size of 2nm, and the degree of catalyst dispersion was improved and de-NO/CO conversion was high. The volume of the NGOC-LNT-SCR catalyst system was optimal in the combination of 1.5+0.5+0.5 with a total score of 165, considering $de-CH_4/NOx$ performance and catalyst cost. For SV $14,000h^{-1}$, the $CH_4$ reduction performance was the highest at about 20%, while the SV $56,000h^{-1}$ was the lowest at about 5%. If the space velocity is small, the flow velocity decreases and the time remaining in the catalyst volume become long, so that the harmful gas was reduced.

• Journal of the Korean Applied Science and Technology
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• v.36 no.4
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• pp.1427-1433
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• 2019

In this paper, Gas engine was tested for the energy of synthesis gas. As excess air ratio increase 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6 in 1800 rpm and synthesis gas, thermal efficiency generally decrease and power generation was 34 kWm at λ 1.4. And excess air ratio increase 1, 1.1, 1.2, 1.3, 1.4 in power generation 34 kWm, thermal efficiency generally increase 34.2%, 36.9%, 37.2%, 37.4%, 38.1%. Total efficiency through power generation consumes 38.7 kg/h of fuel at 30 kWe load and recovers 57.3% of waste heat by recovering 57.3 kW of waste heat through 32.1% power generation efficiency and heat recovery from cooling water and exhaust gas. The total efficiency was 85.8%.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.6
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• pp.626-632
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• 2015

The International Maritime Organization (IMO) has adopted several regulations for the prevention of air pollution from ships. In addition, there is a requirement for shipping liners to reduce greenhouse gas emissions. Accordingly, we need to take measurements to ensure that the steps taken are both efficient and environmentally friendly. It has been determined that the application of the Miller cycle in diesel engines has the effect of both reducing the amount of NOx and improving thermal efficiency. However, this method requires a considerably larger charge air pressure. Therefore, we consider a two-stage turbo-charging system, which not only results in a high charging pressure, but also improves the part load performance with an exhaust-gas bypass system or the application of the Miller cycle. Because of complications associated with the two-stage turbo-charging system, it is complex and difficult to realize a design that optimizes matching between diesel engine and turbo-chargers. Accordingly, it is necessary to perform a quantitative analysis to determine the effects and optimal conditions of these different systems in the early stage of system design. In this paper, we develop a simulation program to model these systems, and we verify that the results of this program are reliable. Further, we discuss methods that can be employed to improve its efficiency.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.8
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• pp.991-998
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• 2013

The fuel injection pipe of a common rail system used in a clean diesel vehicle plays a role in supplying fuel from a rail to the injector of each cylinder connecting the engine under a repeated internal pressure. The fuel injection pressure is increased to over 200 MPa for satisfying EU emission standards and improving fuel efficiency, and a heading process and an autofrettage process are required for preventing folding defects and improving fatigue life. In this study, the flow stress and SN data of the material of the pipe are obtained through a tensile test and a fatigue test. The heading process for checking the folding defects of pipe ends is performed by using FEA. Furthermore, the optimal design of the autofrettage process for improving fatigue life considering not only the compressive residual stresses of the inner surface but also the tensile residual stresses of the outer surfaces of the pipe under the repeated internal pressure is performed by using FEA. To verify the process design, fatigue analysis for the autofrettaged pipe is performed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.6
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• pp.607-614
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• 2013

Nowadays, automotive manufacturers have developed various technologies to improve fuel economy and reduce harmful emissions. The ultra-lean direct injection engine is a promising technology because it has the advantage of improving thermal efficiency through the deliberate control of fuel and ignition. This study aims to investigate the development of a spray-guided-type lean-burn LPG direct injection engine through the redesign of the combustion system. This engine uses a central-injection-type cylinder head in which the injector is installed adjacent to the spark plug. Fuel consumption and combustion stability were estimated depending on the ignition timing and injection timing at various air-fuel ratios. The optimal injection timing and ignition timing were based on the best fuel consumption and combustion stability.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2003.11a
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• pp.91-92
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• 2003

비태인의 급여(0, 600 ppm)가 사료의 단백질 수준(14, 16 ％)에 따라 산란계의 생산성과 난품질, 혈액성상, 간과 가슴육의 일반성분에 미치는 영향을 구명하기 위하여 83주령 하이라인 산란계 192수를 이용하여 12주간 사양실험을 실시하였다. 기초사료는 에너지 수준이 2,800 kcal/kg, methionine과 lysine, cystine의 수준은 단백질 수준에 비례하도록 하였다. 조사항목으로 산란율과 난중, 사료섭취량, 사료요구율, 계란품질은 4주 간격으로 측정했다. 실험 종료시 복강지방과 혈액중 total protein과 albumin, BUN, triglyceride, total cholesterol, HDL-cholesterol, LDL-cholesterol 함량, 간의 methionine, choline 함량, 간과 가슴육의 수분, 조단백질, 조지방 함량을 측정하였다. 산란율은 단백질 수준에 따라 증가하였으며(P＜0.05) 비태인 급여에 의한 차이는 없었다. 난중은 단백질과 비태인 급여로 증가하였으며(P＜0.05) 산란양은 단백질 수준이 증가할수록 감소하였다(P＜0.05). 비태인 급여로 사료 요구율은 현저하게 개선되었지만(P＜0.05), 계란의 품질은 차이가 없었다. 혈청 total protein은 비태인 급여로 현저히 증가하였으며 특히 단백질 14 ％ 급여구에서 크게 증가하였다(P＜0.05). 복강지방 함량은 단백질 수준과 비태인 급여에 따라 감소하는 경향을 보였다. 가슴육과 간의 조단백질 함량은 사료의 단백질 수준에 따라 증가하였다(P＜0.05). 간의 조지방 함량은 비태인의 급여로 감소하는 경향을 보였다. 간의 methionine 함량은 단백질과 비태인 수준에 따라 증가하는 경향을 보였으며 choline 함량은 비태인의 급여에 의해서만 증가하는 경향을 보였다. 따라서 비태인의 급여는 단백질 수준이 높은 조건에서 산란율을 개선시키고 난중을 증가시키며 사료 요구율을 개선한다.록 산가는 증가하는 것을 볼 수 있다. 홍국주의 전자 공여능에 의한 항산화력은 25.6%, 아질산염 소거능은 27.6%, Total phenolic compound 함량은 12.34mg%, ACE저해작용은 38%의 항산화력을 나타냈다.과 $O_2$와 $CO_2$의 농도에서 평균오차 0.2%로 정밀한 것으로 나타났으며 호흡속도 측정용 챔버의 혼합기체 공급측과 배기측의 가스 농도를 3회 반복 측정한 결과 재현성에서는 0.1%이하의 편차로 나타났다. 개방계 호흡속도 자동 측정 시스템을 이용하여 환경기체조성하에서 토마토의 호흡속도를 측정하는 실측 실험을 수행한 결과 2$0^{\circ}C$에서 12.7~42.1mg$CO_2$/kg.hr였으며 12$^{\circ}C$에서 2.5~8.2mg$CO_2$/kg.hr로 일반적으로 보고되고 있는 토마토 호흡속도와 일치하는 결과를 나타내었다.다.환원당인 sucrose 함량은 계속 증가하였고 fructose, glucose, sorbitol의 함량(추황의 sorbitol을 제외)은 생장이 촉진됨에 따라 증가하다가 다시 점차적으로 감소하였다. 이러한 결과는 총당과 환원당의 측정결과와 일치한 것으로 나타났다. 결론적으로 배의 성장에 따라 산 함량은 감소하였고 당 함량은 증가하였다.luco-pyranoside, quercetin 7-O- -glucopyranoside, acacetin 7-O-$\beta$-D-glucuronide and apigenin-6-C-$\beta$-D-glucopyranosyl-8-C-$\beta$-D-glucopyranoside were first isolated and identified from safflower leaf. Among these flavonoids, luteolin