• 재활복지공학회논문지
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• 제8권1호
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• pp.19-26
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• 2014

본 연구는 고령자를 대상으로 마이크로 버블과 LED 조명을 이용하여 반신욕 시 인체의 변화를 평가하였다. 피험자는 남성 고령자 6명과 여성 고령자 7명을 대상으로 마이크로 버블을 이용하는 그룹(남성 3명, 여성 4명)과 마이크로 버블을 이용하지 않는 그룹(남성 3명, 여성 3명)으로 나누었다. 실험은 LED 조명의 색상을 달리하여 4회 진행하였다. 실험 결과 교감 신경에 비하여 부교감 신경의 활성화를 보였으며(마이크로 버블을 이용 한 반신욕 : 21.41%), 빨간색 조명과 마이크로 버블을 이용한 반신욕에서 $5.93^{\circ}C$로 체열의 가장 큰 증가를 보였다. 본 결과는 마이크로 버블과 LED 조명이 반신욕 시스템에 활용될 거라 사료된다.

• 한국물환경학회지
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• 제27권6호
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• pp.877-884
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• 2011

In this paper, the removal characteristics of dissolved organic carbon (DOCs) by micro bubble ozonation process and $O_3/UV$ process were comparatively studied. In the point of DOC removing reaction coefficient, micro bubble ozonation system and $O_3/UV$ process had not significant difference, $0.0120sec^{-1}$ and $0.0141sec^{-1}$. Therefore micro bubble ozonation process is more suitable for tertiary treatment of sewage in the point of installation and maintenance cost-reducing. The optimum ozone injection rate was 2.0 g $O_3/g$ DOC and HRT was 3 min for the micro bubble ozonation process. The removal efficiency of DOC and SUVA in micro bubble ozonation system was 32.8% and 58.3% respective. Biological aerated filter (BAF) process was installed to remove soluble organic material increased by micro bubble ozonation system. And the effluent BOD of BAF was below 1.0 mg/L. In the view of cost-effectiveness, $O_3/BAF$ process was more profitable than $O_3/UV/BAF$ process for tertiary treatment of sewage. In order to nitrify ammonia in the BAF process completely, $NH_4{^+}-N$ concentration in the influent water of BAF should be designed considering low water temperature in the winter season.

• 수산해양기술연구
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• 제56권4호
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• pp.407-418
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• 2020

Mass mortality of mariculture fish due to high summer temperatures is a major issue in the mariculture industry in many coastal waters of Korea, yet measures to mitigate the impact are generally limited. We injected a micro-bubble of liquefied oxygen into the bottom of rockfish cages (about 6-8 m deep) in order to maximize the dispersal of micro-bubbled seawater and reduce fish mortality. The injection of low-temperature oxygen in micro-bubbles lowered the water temperature at the injection area by as much as 1℃ and increased dissolved oxygen concentration by 0.5 ppm. In early August, following a week with persistent high water temperature (above 28.5℃), there was an increase in fish mortality despite the micro-bubble system, which resulted in approximately 7% death of the total introduced fish population. However, this mortality appeared to be much lower than mortality reported in a neighboring mariculture facility (approximately 50% mortality). We also estimated the volume that can be recirculated with pumped seawater using a micro-bubble system. We suggest that this approach of injecting liquefied oxygen through a micro-bubble system may reduce fish mortality during high temperature periods.

• 한국전기전자재료학회논문지
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• 제21권3호
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• pp.222-226
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• 2008

With different seed adhesion methods, we obtained two different aspects with or without micro-bubble in the interface between a seed and a dense graphite seed holder. To improve the quality of SiC wafer, we introduced a sucrose caramelizing step at the seed adhesion using the sucrose, The n-type 2 inch single crystal exhibiting the polytype of 6H-SiC were successfully fabricated and carrier concentration levels of about $10^{16}/cm^3$ was determined from Hall measurements, As compared to the characteristics of SiC crystal grown with micro-bubble in the interface between the seed and the dense graphite seed holder, the SiC crystal grown without micro-bubble definitely exhibited lower resistivity, lower micropipe density and higher mobility relatively.

• 한국수소및신에너지학회논문집
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• 제27권1호
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• pp.121-126
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• 2016

Hydraulic performance of a micro-bubble pump has been analyzed by numerical simulation and experimental measurements. Flow recirculation apparatus between the pump inlet and outlet reserviors has been adopted to measure pump performance according to flow conditions sequentially. To analyze three-dimensional flow field in the micro-bubble pump, general analysis code, CFX, is employed. SST turbulence model is employed to estimate the eddy viscosity and compared the pump performance to k-${\varepsilon}$ model. Unstructured grids are used to represent a composite grid system including blade, casing and inlet casing. It is found that the numerical model used in the present study is effective to evaluate the pump performance. From the numerical simulation, low velocity region due to pressure loss is decreased where pump efficiency has maximum value. Detailed flow field inside the micro-bubble pump is also analyzed and compared.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.341-346
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• 2004

Motion of a bubble inside narrow tube is numerically studied. The numerical code assumes axi-symmetric incompressible flow field. The surface of the bubble is captured by VOF (Volume Of Fluid) method, and it is advected by MARS (Multiphase Advection and Reconstruction Scheme). Air bubble inside water is first studied, and it was found that a strong vortex, which is induced by the pressure difference caused by the surface tension, is formed at the rear part of the bubble. Then flow parameters are parametrically varied to understand the correlation between the bubble shape, the bubble velocity, and the flow parameters. The parametric study revealed that the aspect ratio of the bubble mainly depends on We number, and the oscillation of the bubble speeds is dependent on Re number.

• 전기학회논문지
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• 제61권1호
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• pp.94-98
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• 2012

The behavior of ozone micro bubble cleaning system was investigated to evaluate the solution as a new method of solar cell wafer cleaning in comparison with former conventional RCA cleaning. We have developed the ozone dissolution system in the ozonated water for more efficient cleaning conditions. The optimized cleaning conditions for solar cell wafer process were 10 ppm of ozone concentration and 12 minutes in cleaning periods, respectively. We have confirmed the cleaning reliability and cell efficiencies after ozone micro bubble cleaning. Using this new cleaning technology, it was possible to obtain higher efficiency, higher productivity, and fast tact time for applying cleaning in the fields on bare ingot wafer, LED wafers as well as the solar cell wafer.

• 설비공학논문집
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• 제27권10호
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• pp.520-526
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• 2015

The characteristics of gas-liquid Taylor (Slug) flow in a square micro-channel of $600{\sim}600{{\mu}m}$ were investigated experimentally in this paper. The test fluids were nitrogen and water. The liquid and gas superficial velocities were 0.01~3 m/s and 0.1~3 m/s, respectively. Bubble and liquid slug length, bubble velocity, and frequency were measured by analyzing optical images using a high speed camera. Bubble length decreased with higher liquid flow rate, which increased dramatically with higher gas flow rate. However, slug length did not vary with changes in inlet liquid conditions. Additionally, bubble velocities and frequencies increased with higher liquid and gas flow rates. It was found that measured bubble lengths were in good agreement with the empirical models in the existing literature, but slug lengths were not.

• 대한기계학회논문집B
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• 제28권6호
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• pp.659-664
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• 2004

It is important to measure precisely the size and velocity of micro-bubbles used in various field. The synchrotron X-ray micro-imaging technique was employed to measure the size and velocity of micro-bubbles moving in an opaque tube simultaneously. Phase contrast images were obtained at interfaces of micro-bubbles between water and air due to their different refractive indices. The X-ray micro-imaging technique was found to measure an optical fiber with an accuracy of 0.2%. Micro-bubbles of 20∼60$\mu\textrm{m}$ diameter moving upward in an opaque tube (${\Phi}$＝2.7mm) were tested to measure bubble size and up-rising velocity. For DI water, the measured velocity of micro-bubbles is nearly proportional to the square of bubble size, agreed well with the theoretical result. In addition, the synchrotron X-ray micro-imaging technique can measure accurately the size and velocity of several overlapped micro-bubbles.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1744-1748
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• 2004

It is important to measure precisely the size and velocity of micro-bubbles used in various field. The synchrotron X-ray micro-imaging technique was employed to measure the size and velocity of micro-bubbles moving in an opaque tube simultaneously. Phase contrast images were obtained at interfaces of micro-bubbles between water and air due to their different refractive indices. The X-ray micro-imaging technique was found to measure an optical fiber with an accuracy of 0.2%. Micro-bubbles of $10{\sim}60{\mu}m$ diameter moving upward in an opaque tube (${\phi}=2.7mm$) were tested to measure bubble size and up-rising velocity. For DI water, the measured velocity of micro-bubbles is nearly proportional to the square of bubble size, agreed well with the theoretical result. In addition, the synchrotron X-ray micro-imaging technique can measure accurately the size and velocity of several overlapped micro-bubbles.