• 대한조선학회논문집
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• 제40권4호
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• pp.22-29
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• 2003

New high-speed depressurized circulating water channel was designed by using the CFD code. Flow in the channel has free surface and pressure in the test section can be depressed. In this study, Flow separation and bubble occurrence were considered in designing the contraction nozzle shape for better flow uniformity Tn the test section. To supplement velocity defect due to the free surface, nozzle injection system more effective in high-speed flow was installed instead of drum system. Necessary power and injection techniques were proposed. And guide vane arrangement was analyzed to reduce the flow resistance and keep quiet free surface from ´surging´. Wave absorber was devised to reduce the wave resistance and to prevent the entrainment of air to the diffuser.

• Journal of Mechanical Science and Technology
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• 제18권8호
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• pp.1418-1427
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• 2004

Combined formulation developed for the fluid-particle mixture is introduced to simulate the biocube-fluid mixture flow, which is utilized for sewage disposal. Some tricky boundary conditions are introduced in order to simulate the effect of screen wall and air bubble, which is injected from the bottom of sewage reservoir. It has been shown that a circulated flow pattern, which was observed in experiment, is reproduced from the present numerical simulation. Furthermore, the effect of biocube density on the distribution pattern of biocube is also studied. It has been shown that a biocube whose density is slightly smaller than that of surrounding fluid or neutrally buoyant one are optimal for the uniform distribution of biocube.

• Journal of Korean Neurosurgical Society
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• 제56권6호
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• pp.521-526
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• 2014

The authors report a case of symptomatic epidural gas accumulation 2 weeks after the multi-level lumbar surgery, causing postoperative recurrent radiculopathy. The accumulation of epidural gas compressing the dural sac and nerve root was demonstrated by CT and MRI at the distant two levels, L3-4 and L5-S1, where vacuum in disc space was observed preoperatively and both laminectomy and discectomy had been done. However, postoperative air was not identified at L4-5 level where only laminectomy had been done in same surgical field, which suggested the relationship between postoperative epidural gas and the manipulation of disc structure. Conservative treatment and needle aspiration was performed, but not effective to relieve patient's symptoms. The patient underwent revision surgery to remove the gaseous cyst. Her leg pain was improved after the second operation.

• Journal of Advanced Marine Engineering and Technology
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• 제25권6호
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• pp.1250-1259
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• 2001

This study was experimentally performed to investigate sea water freezing behavior along parallel cooled plate with bubbly flow The experiments were carried out for a variety of parameter, such as sea water velocity, air-bubble flow rate, and cooled-plate temperature. The shape of freezing layer, freezing rate and salinity of frozen layer were observed and measured. It was found that the experimental parameters gave a great influence on the freezing rate and the salinity of the frozen layer.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.366-372
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• 2007

Self-sensing measurement of piezo inkjet and its application are discussed. The pressure wave inside the inkjet dispenser was measured by current measurement due to self-sensing capability of PZT. The pressure wave measured from current was verified by commercially available laser vibrometer. Here, two applications using self-sensing signal were discussed: waveform design for high speed jetting and condition monitoring. For waveform design, two pulse waveform was designed based on self-sensing signal such that the pressure wave after droplet formation can be minimized. For condition monitoring, self-sensing signal was shown to be effective in detecting air bubble trapped in inkjet printhead.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2010년도 춘계학술발표회 논문집
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• pp.7-7
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• 2010

Flotation deinking is a common practice for removing ink from recovered paper, and it is becoming a key process in many recycling paper mills. Flotation deinking was successfully introduced to the paper recycling industry in the 1980s, and its applications in wax removal, stickies control, and fiber fractionation have attracted great research interest. A successful flotation process has three major efficient subprocesses: the detachment of the ink particles from the fibers, the effective adhesion of the ink particles onto air bubble surfaces, and the removal of froth and ink particles from flotation cells. Surfactants can affect these subprocesses either positively or negatively. To understand how a surfactant can positively and negatively affect the flotation deinking process, the basic chemistry of surfactant in solution should be discussed.

• 한국식품과학회지
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• 제18권2호
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• pp.93-97
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• 1986

호화 옥분을 결합제로 첨가하고 진공탈기 압출법으로 단백질변성온도보다 저온에서 보리국수를 제조하였다. 면대 안의 기포제거로 습윤국수의 강도가 높아 졌으며건조국수의 조리안정성도 높아 졌다. 호화 옥분 첨가는 습윤국수 면대 강도 확보에 필수적이었는데 첨가수준이 높아지면 국물탁도가 높아지므로 20% 첨가가 적정수준이었으며 반죽액은 3% 대두단백질용액으로 하면 국수 품질개선에 효과가 있었다.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2005년도 제31회 KOSCO SYMPOSIUM 논문집
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• pp.110-119
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• 2005

The combustion characteristics of binary component single droplets hanging at the tip of a quartz fiber are studied experimentally at different environmental pressures and temperatures under normal gravity. Normal Heptane and Normal Hexadecane are selected as two fuels with high difference in boiling temperatures. A falling electrical furnace in a high pressure vessel has provided high temperature environment. Nitrogen and air have formed the environment to study evaporation and combustion, respectively. The initial diameter of droplet was ranging from 1.1 to 1.3 mm. The evaporation and combustion processes were recorded by a high speed digital camera. Some characteristics of droplet burning under different environment conditions and different droplet composition have been investigated. Microexplosion of droplet take places under atmospheric pressure. Bubble formation and its consequent result, incomplete droplet disintegration which presents in all binary compositions, do not appear at high pressure. The initiation of combustion, always takes place in the bottom of droplet due to buoyancy effect of relatively cold fuel vapor. Also, the burning of binary droplet produces soot when the pressure is high.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 학술대회
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• pp.321-326
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• 2008

The engineering use of CFD is recently extending to the prediction of maneuvering characteristics, response to waves, propeller performance, and so on. The focus of the research is shifting to simulation of more complex processes. Typical examples of such processes are bow or stern slamming, green water problem, propeller cavitation, hull-propeller interaction, or drag reduction by bubble injection. Those processes are characterized by keywords such as high nonlinearity, unsteadiness, multiphase flow. In this paper, two new attempts which have been recently made by the author's research grop are presented. One is the prediction of propeller cavitation and its effect to the ship hull. The others is the application to the drag reduction by use of air bubbles.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년 추계학술대회논문집
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• pp.321-326
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• 2008

The engineering use of CFD is recently extending to the prediction of maneuvering characteristics, response to waves, propeller performance, and so on. The focus of the research is shifting to simulation of more complex processes. Typical examples of such processes are bow or stern slamming, green water problem, propeller cavitation, hull-propeller interaction, or drag reduction by bubble injection. Those processes are characterized by keywords such as high nonlinearity, unsteadiness, multiphase flow. In this paper, two new attempts which have been recently made by the author's research group are presented. One is the prediction of propeller cavitation and its effect to the ship hull. The other is the application to the drag reduction by use of air bubbles.