• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.5
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• pp.30-37
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• 2001

Most gasoline engines employ a port injection system to achieve the better fuel-air mixing. A part of injected fuels adheres to the wall or intake valve and forms a film of liquid fuel. The other is secondarily atomized by the spray-wall interaction. A better understanding of this interaction will help in designing injection systems and controlling the strategies to improve engine performance and exhaust emissions. In the present research, the spray-wall interaction was investigated by a laser sheet visualization method. The shape of sprays was pictured at various impinging velocities and angles. The fuel dispersion was estimated by fluorescence light, and the atomization was evaluated by the enlarged images of droplets. The experimental results were compared with model predictions which are based on OPT method. The model has been modified to have the better agreement with the experimental result, and was implemented in the KIVA-II code.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.6
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• pp.109-114
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• 2001

Forming pressure of the rupture disc has been analyzed theoretically and verified by experiments. Final shape of the rupture disc after forming process is assumed to be hemi-ellipsoid for small height of the rupture disc. The predicted forming pressures are in good agreement with those by experiment. A new simple model has been proposed to predict the burst pressure of the rupture disc. Experimental results show that the proposed model of burst pressure describes the bursting characteristics of the rupture disc very well.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.206.1-206.1
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• 2011

Recently, various developments in the area of small hydropower have being made and small hydro turbines are suitable for domestic use because it is a clean and renewable energy source. A small hydropower generator produces power by using the different water pressure levels in pipe lines and energy which was initially wasted by use of a reducing valve at the end of the pipeline is instead collected by a tubular-type hydro turbine in the generator. In this study, in order to acquire the performance of tubular-type hydro turbine applied, the output power, head, efficiency characteristics due to the different guide vane and runner vane angle are examined in detail. Moreover, influences of pressure and velocity distributions with the variation of guide vane and runner vane angle on turbine performance are investigated by using a commercial CFD code.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.245-245
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• 2000

후각기는 후각신경과 삼차신경의 기능을 객관적이고 정량적으로 검사할 수 있는 기기로, 객관적으로 인정받을 수 있는 후각기의 제작에는 많은 어려움이 있기 때문에, 현재까지 후각신경과 삼차신경의 기능을 정확하게 측정할 수 있는 방법이 없었다. 그러나, 산업이 발달하고 공해가 더욱 심해질수록 후각의 변화가 생기고, 비강 내 질환이나, 공해물질 등에 의해 삼차신경이 민감한 반응을 일으키므로, 앞으로는 이 신경들의 측정이 중요할 것으로 여겨진다. 또한 각종 산업분야에서 이제까지 사람의 미각이나 후각에 의존하여 제품을 생산해오던 방법을 변화시켜 객관적인 수치를 이용하여 제품을 생산할 수 있다. 따라서 이번 연구에서는 사람이나 동물에게 다양한 후각물질을 원하는 정확한 농도로 투여하는 기기로, 온도와 습도를 사람의 신체 조건과 동일한 공기와 혼할하여 원하는 정확한 농도(ppm)의 후각 자극을 만들어 mass flow controller와 solenoid valve를 이용하여 square-shape의 자극모양이 되도록 한 후, 피검자에게 자극하여 전기생리학적 반응을 얻는 기기를 개발하였다.

• Journal of Veterinary Clinics
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• v.21 no.1
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• pp.83-86
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• 2004

A 4 year old mixed female dog was presented dyspnea, anorexia and syncope. In blood smear test, a lot of heartworm larvae were observed. In thoracic radiography, "reverse D" shape was observed. So, this case was considered with heartworm disease. In echocardiography, marked left heart hypertrophy was presented. In M-mode view, aortic valvular stenosis was found. After mongrel dog died, aortic valvular stenosis was reconfirmed in necropsy. After all, the dog died of pulmonary edema because of aortic valvular stenosis caused left heart failure.t failure.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.916-921
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• 2006

Column mixer is one of the facility to mix fluids at petrochemical plants. The column vibration is caused by pumps for fluid inflow and mixing of inside fluids. This fluid induced vibration is mainly responsible for the reduction of column life. Measurements were performed three times for understanding the vibration characteristics of the column. First experimental results showed the need of stiffness reinforcement. After the reinforcement work, second measurement conformed the difference between two results. Modal analysis was also performed to investigate the resonance of the column vibration and the damage of the rib plate. To confirm the generation of the fluid instability in the column mixer fluid structure interaction analysis using ADINA/FSI was performed which showed the necessity of the modification of the rotary valve.

• Journal of the korean Society of Automotive Engineers
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• v.10 no.6
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• pp.85-91
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• 1988

The purpose of this study is to investigate the flow through the intake and exhaust system of a spark ignition engine. The flow was assumed to be one-dimensional, compressible and unsteady, and carburetor, muffler, valve and junction are modelled as boundary conditions according to their flow characteristics. In the experiment, four cylinder gasoline engine is used and the pressures in the intake and exhaust pipes and in the cylinder are measured and compared with the results of numerical analysis. In consequence of the comparison, four periods of pressure wave in a cycle are observed in both case of experiment and prediction. In case of exhaust pipe, the results obtained from the experiment are in accord with that from calculation. The results of the intake system show some differences with each other due to the complication in shape, but the periods of both case concur well.

• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.5
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• pp.66-73
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• 1994

The configuration effects of a tumble adaptor which transforms tumble into swirl on the intake tumble characterization under steady flow condition have been investigated by LDV measurement The following parameters were involved to test their effects on tumble-swirl conversion characteristics ; the cylinder height and its bottom shape, measuring position in the swirl induction pipe, and the relative direction of the induction pipe. The short cylinder height and the flat bottom of the tumble adaptor were found effective for the generation of tumble in the cylinder, allowing higher tumble-swirl conversion efficiency.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.687-688
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• 2006

DC솔레노이드 밸브의 성능을 나타내기 위해 여러 가지 중요한 파라메터들이 존재한다. 최소 혹은 최대 스트로크 시의 흡입력, 온도상승, 소비전력 그리고 동작시간 등이 있다. 본 논문에서는 동자시간을 최소화시키기 위해 반응표면법을 이용하여 DC솔레노이드 밸브의 형상 최적화를 수행하였고 그 결과를 유한요소법을 이용하여 검증한다.

• International Journal of Air-Conditioning and Refrigeration
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• v.9 no.2
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• pp.51-61
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• 2001

A numerical study has been conducted to characterize the transient pressure in a simple water supply pipe system with an air chamber by utilizing a commercial code that employs the method of characteristics. Some results produced for validation in the study agree quite well with the previously reported. Several parameters are than varied. Among them are the valve closure time, the wave speed, the static pressure, the polytropic exponent, the air chamber volume, the diameter and the shape of orifice in the air chamber, etc, while the water temperature and velocity are kept constant at $20^\circ{C}$ and 0.8m/s, respectively. Results reported in this parametric study may be useful to understand the unsteady behavior of the system.