• Journal of Bio-Environment Control
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• v.1 no.2
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• pp.169-174
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• 1992

This experiment was carried out to investigate the possibility of practical use of intermittent soaking system(ISS) in hydroponicaly growing tomato. There were four treatments which were NFT, Aeroponics, and ISS with 10 and 15 minute soaking intervals. 1. Plant height is highest in NFT, but main root length is longest in ISS. While stem diameter and leaf number were not significantly difference. 2. Fresh and dry weight were heavier in NFT than those of other systems at early growth stage, but the heavier in ISS system, the growth more develop. 3. In 43 days after treatment, the number of flowerlet was largest in aeroponics, and then ISS and NFT in order. Fruit weight per plant was also heaviest in aeroponics. 4. Average yield per plant were 1929.1g in aeroponics, 1475.2g in ISS with 10 minute soaking interval, 1276.2g in NFT and 1084.8g in ISS with 15 minute soaking interval. 5. Average fruit number per plant were 11.0 in aeroponics, 9.7 in NFT, 8.3 in ISS with 15 minute soaking interval, and 7.7 in ISS with 10 minute soaking interval. Average fruit weight were 192.9g in aeroponics, 172.4g in ISS with 10 minute soaking interval, 134.0g in NFT and 126.0g in ISS with 15 minute soaking interval. 6. Average fruit length was longer in aeroponics and ISS with 10 minute soaking interval than in the NFT and ISS with 15 minute soaking interval. Average fruit width was similarly wider in NFT, aeroponics and ISS with 10 minute soaking interval than in ISS with 15 minute soaking interval.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.3
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• pp.128-136
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• 1997

Spray characteristics of a fuel injector have an important effect upon engine power and emission. Thus this study was investigated the spray characteristics of the intermittent injection using a gasoline fuel injector. Image processing system and PDA system were utilized for visualization of a spray behavior and measurements of a droplet size and velocity, respectively. Fuel injection duration was fixed with 3ms and injection pressure was varied such as 250kPa, 300kPa, 350kPa. for a high fuel injection pressure, spray tip arrival time was fluctuated at a vigorously disintegrated cross section. Axial velocity was linear correlated with fuel droplet size in the time interval of an injected main spray at spray downstream.

• Journal of ILASS-Korea
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• v.3 no.1
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• pp.34-42
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• 1998

The correlation between the droplets size and the velocity are investigated for an intermittent spray of the pintle type fuel injector employed in a port injection gasoline engine. The analysis such as the mean droplet size, SMD, and velocity under the fixed injection period and varied fuel pressures are conducted utilizing PDPA systems. As results, the experimental data obtained, show that the larger droplet sizes. the higher velocities during the spray tip arrival time, and that at Z=70mm, r=8mm, both droplet sizes and velocities are peak. At the upstream, flow of droplets are dominated by injection pressure, which are more effected inertia force of droplets at the downstream of Z=70mm.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1992.12a
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• pp.29-30
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• 1992

최근 근권의 산소부족 문제를 근본적으로 해결할 수 있는 수경능법으로서 분무경에 관한 관심은 매우 높으며 분무경의 우수성이 실증적으로 제시되고 있으나 분무경의 경우 고압을 필요로 하므로 장치가 복잡해지거나 엽체류의 경우 분무노즐과의 거리에 따라 생장이 균일하지 않는 문제점을 갖고 있으므로 분무경과 같이 근권산소 문제를 근본적으로 해결하는 효과를 가지면서도 취급 및 관리가 편리한 수경시스템의 개발이 절실히 요구되고 있다. (중략)

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.9
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• pp.1198-1206
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• 1997

The flow characteristics of an intermittent fuel injection into a stationary ambient air were investigated using gasoline. The measurements were made by two-channel, air cooling type Phase Doppler Anemometer(PDA) system (DANTEC, 750 MW). And a pintle type injector of MPI (Multi-point Port Injection) system was utilized as a fuel injector. The PDA receiver optic was set up in a 60.deg. C forward scatter arrangement to obtain the optimum scattering signal of fuel droplets. The data were obtained by synchronizing PDA system with the fuel injection period, and the axial and radial velocity and turbulent components of fuel droplets were mainly measured for the analysis of temporal and spatial distribution depending upon the fuel injection pressures.

• Journal of ILASS-Korea
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• v.5 no.1
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• pp.30-40
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• 2000

The characteristics of liquefied butane spray are expected to be different from conventional diesel fuel spray, because a kind of flash boiling spray is expected when the back pressure is below the saturated vapor pressure of the butane(0.23MPa at 298K). The ambient pressure was held at a pressure above(0.37MPa) and below(0.15MPa) the fuel vapor pressure. The axial velocities, radial velocities, and size distributions in butane sprays were measured with PDPA(Phase Doppler Particle Analyzer) system. The PDPA measurement showed a smaller SMD at the 0.15MPa chamber pressure, compared to the 0.37MPa case. Log-hyperbolic density function for the droplets size distribution can be fitted to the experimental results of a liquefied butane spray.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.3
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• pp.27-34
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• 2001

This experimental study is to investigate the intermittent spray characteristics of the multi-hole diesel nozzle with a 2-spring nozzle holder. Without changing the total orifice exit area, its hole number varied from 3($d_n=0.42mm$) to 8($d_n$=0.25mm). Through the use of the 2-D PDPA(phase Doppler particle analyzer), the droplet diameter and the velocity of the diesel spray injected intermittently from the multi-hole nozzle into the still ambient were measured. And the calculations of time-resolved diameters, SMD and AMD were made. The results can be summarized as follows. The spray of the multi-hole nozzle consisted of three parts. These are the leading edge, the central part and the trailing edge. And most of droplets produced at the trailing edge of spray. In the spray flow field, the measuring position which represented the intermittent spray characteristics well was near the nozzle tip. But at the downstream of the spray, its characteristics disappeared, and spray behavior showed a quasi steady state regardless of the time evolution of the spray. The overall mean SMD of the spray increased with the spray development, and showed their maximum value near 1.5ms regardless of hole number.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.3
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• pp.466-474
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• 2004

The characteristics of liquefied butane spray are expected to be different from conventional diesel fuel spray, because a flash boiling spray is expected when the surround pressure is below the saturated vapor pressure of the butane(0.23MPa 98K). The axial velocities. radial velocities. and size distributions in butane sprays were measured with PDPA(Phase Doppler Particle Analyzer) system. Sprays were macroscopically observed by using the high speed camera in case that the surround pressure is 0.37MPa and 0.15MPa. respectively. Compared with the conventional spray. the reversed results were investigated when the surround pressure is below the saturated vapor pressure of the butane.

• KOREAN POULTRY JOURNAL
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• v.36 no.7 s.417
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• pp.70-74
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• 2004

최근 육종개량의 발전과 성과로 인하여 대형화되었지만 고밀도 사육에 의해서 하절기 열사병과 심한 더위로 인한 생산성 저하가 큰 문제로 혹서기에 대두되고 있어 그 대응책을 반드시 세워야 할 것이다. 하절기 온도관리 대책으로서는 계사내의 공기유통을 좋게 하는 것이 가장 기본이므로 충분한 환기에 의해 닭의 체감온도를 낮추어 주게 되는 것이다. 그러나 우리나라와 같이 여름철의 기후 특성이 고온다습한 경우는 습도가 높아지게 되면 체감온도는 낮아지지 않는다. 그러므로 계사내의 습도를 저하시키기 위해서 환기휀 등을 이용해 깔짚과 계분을 건조시키는 것도 한가지방법이다. 일반적으로 열사병 대책으로 실시하고 있는 방법으로서는 입기구에 물 분무, 지붕에 물 분무, 계사내의 미세한 분무냉각 등 물을 이용하는 방법이나, 환풍기의 설치, 닥트송풍을 이용한 방법, 거칠고 얇은 그물에 의한 차광 등의 방법으로 온도를 낮게 할 수가 있다. 특히 산란계의 경우 여러 연구보고 자료에 의하면 산란계를 고온 환경에서 사육할 경우 난각질이 저하된다고 하는 보고가 많이 있다. 1일 중에 환경온도를 주기적으로 변화시킨 경우는 일정하게만 유지해 주는 환경온도에 비해서 난각질과 난각강도는 낮아지게 된다. 또한 산란계에 있어서 간헐점등에 대해서는 에너지 수준을 줄이는 기술, 또는 사료절감을 유도하는 방법은 계속 연구되고 있다. 따라서 다음은 하절기 산란$\cdot$육계사의 적온유지를 위한 온도관리 사례에 대하여 이야기하고자 한다.

• Journal of ILASS-Korea
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• v.4 no.1
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• pp.45-54
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• 1999

The spray characteristics of a direct injection multi-hole diesel nozzle having the 2-spring nozzle holder were investigated by using the image processing system and a PDPA(phase Bowler particle analyzer) system. The spray tip penetration, the spray angle, and the droplet diameter and velocity with the variation of the pump speed, injection quantity were measured. From, the experiments, we know that there are small droplets which are not to be detected with spray image around the leading edge of the spray. In order to represent the mean characteristics of the intermittent spray very well, it is very important to set the time windows accurately. From the measurements along the axis of the spray, close to the nozzle, the initially injected droplets are overtaken by droplets that follow them. And also there are the maximum axial mean velocity and SMD at the following part of the leading edge of the spray.