• 전기학회논문지
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• 제59권3호
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• pp.604-608
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• 2010

An electric fan for cooling high density electronic devices is limited and operated in very low efficiency. The corona discharge is utilized as the driving mechanism for an ionic gas pump, which allows for air flow control and generation with low noise and no moving parts. These ideal characteristics of ionic pump give rise to variety applications. However, all of these applications would benefit from maximizing the flow velocities and yields of the ionic pump. In this study, a needle-mesh type ionic pump has been investigated by focusing on the radius of curvature of corona needle points elevating the ionic wind velocity and efficiency. It is found that the radius of curvature of the corona discharge needle point influences significantly to produce the ionic wind and efficiency. As a result, an elevated ionic wind velocity and increased ionic wind generation yield can be obtained by optimized the radius of curvature of the corona needle electrode.

• 전기학회논문지
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• 제57권11호
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• pp.2023-2026
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• 2008

Cooling technologies using natural and forced convection are limited and operated in very low efficiency. The corona discharge is utilized as the driving mechanism for an ionic pump, which allows for air flow control and generation with low noise and no moving parts. These ideal characteristics of ionic pump give rise to variety applications. However, all of these applications would benefit from maximizing the flow velocities and efficiencies of the pumps. In this study a needle-mesh type ionic pump, with a ring type third electrode installed just near the needle point, has been investigated by focusing on elevating the ionic wind velocity and efficiency. As a result, the enhanced ionic wind velocity and increased power yield can be obtained with the proposed ionic pump with the third electrode.

• 전기학회논문지
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• 제57권9호
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• pp.1594-1598
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• 2008

The ionic air pump can be used towards the thermal management of micro-electronic devices, since the size of pump can be reduced to micrometer orders. In addition, an air pump allows air flow control and generation with low noise and no moving parts. These ideal characteristics of the pump give rise to variety applications. However, all of these applications would benefit from maximizing the flow velocities of the pumps. In this study a surface discharge type air pump, with a third electrode, has been investigated by focusing on elevating the wind velocity and efficiency. As a result, the enhanced ionic wind velocity could be obtained with the third electrode of the proposed air pump.

• 전기학회논문지
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• 제58권5호
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• pp.994-998
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• 2009

Existing cooling technologies no longer provide adequate heat dissipation due to excessive heat generation caused by the growing component density on electronic devices. An ionic gas pump can be used for the thermal management of micro-electronic devices, since the size of pump can be reduced to a micrometer scale. In addition, the gas pump allows for gas flow control and generation without moving parts. This ideal property of gas pump gives rise to a variety of applications. However, all these applications require maximizing the wind velocity of gas pump. In this study a barrier discharge type gas pump, with a needle-shaped corona electrode instead of a plate-shaped corona electrode, has been investigated by focusing on the corona electrode shape on the wind velocity and wind generation yield. As a result, the enhanced wind velocity and wind generation yield of 1.76 and 3.37 times were obtained with the needle-shaped corona electrode as compared with the plate-shaped corona electrode of the proposed barrier discharge type gas pump.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 Techno-Fair 및 합동춘계학술대회 논문집 전기물성,응용부문
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• pp.139-140
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• 2008

Cooling systems for electronic equipments are becoming more important. Cooling technologies using natural and forced convection are limited and operated in very low efficiency. A corona discharge is utilized as the driving mechanism for anair pump, which allows for airflow generation with low noise and no moving parts. However they do not enhance the flow rate and overcome the control mechanism of the pump. In this study a point-mesh type air pump, with a third electro de installed near the corona point, has been proposed and investigated by focusing on elevating the ionic wind velocity and power yield. As a result, the significantly enhanced ionic wind velocity and tremendously increased power yield can be obtained with the proposed air pump system.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권7호
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• pp.298-304
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• 2003

IPMC(Ionic Polymer-Metal Composite) is a highly sensitive actuator that shows a large deformation in presence of low applied voltage. Generally, IPMC can be fabricated by electroless plating of platinum on both sides of a Nafion (perfluorosulfonic acid) film. When a commercial Nafion film is used as a base structure of the IPMC membrane, the micro-pump structure and the IPMC membrane are fabricated separately and then later assembled, which makes the fabrication inefficient. Therefore, fabrication of an IPMC membrane and the micro-pump structure on a single wafer without the need of assembly have been developed. The silicon wafer was partially etched to hold liquid Nafion to be casted and a 60-${\mu}{\textrm}{m}$ thick IPMC membrane was realized. IPMC membranes with various size were fabricated by casting and they showed 4-2${\mu}{\textrm}{m}$ displacements from $4mm{\times}4mm$ , $6mm{\times}6mm$, $8mm{\times}8mm$ membranes at the applied voltage ranging from 2Vp-p to 5Vp-p at 0.5Hz. The displacement of the fabricated IPMC membranes is fairly proportional to the membrane area and the applied voltage.

• 한국가시화정보학회지
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• 제17권1호
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• pp.43-52
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• 2019

'Ionic wind' is phenomenon induced by corona discharge which occurs when large electric potential is applied to electrodes with high curvature. The ionic wind has advantage that it could generate forced convective flow without any external energy like separate pump. In this study, 'pin-mesh' arrangement is utilized for experiments. First, optimization of configuration is conducted with local momentum of ionic wind behind the mesh. Empirical equation for prediction about velocity profile was derived using the measured results. Secondly, the enhancement of mass transfer rate of acetone with ionic wind was analyzed. Also, the drying efficiency using a fan which has same flow rate was compared with ionic wind for identification of additional chemical reaction. At last, the drying process of organic solvent was visualized with image processing. As a result, it was shown that the use of ionic wind could dry organic matter four times faster than the natural condition.

• 대한의용생체공학회:의공학회지
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• 제36권6호
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• pp.291-295
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• 2015

Various types of implantable drug delivery devices have attracted significant attention for several decades to improve drug bioavailability and reduce side effects, thus enhancing therapeutic efficacy and patients' compliance. However, when implanted into the body, the devices may be influenced by the changes in physiological condition, such as temperature, pH or ionic concentration. Thus, the drug release rates could be also altered concurrently. Therefore, in this work, we employed an implantable ALZET$^{(R)}$ Osmotic Pump, which has been widely used to locally deliver various therapeutic agents and examined the effect of pH, temperature and ionic concentration on its drug release rate. For this, we performed in vitro cell tests to simulate the condition of local tissues influenced by the altered drug release rates, where we used diclofenac sodium as a model drug.

• Journal of Chest Surgery
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• 제18권2호
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• pp.205-213
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• 1985

It is well documented that calcium is essential to cardiac contraction and the amplitude of contractility is proportional to the ionized calcium not to total calcium. Changes of serum ionic calcium before and after extracorporeal circulation were observed in fifty two patients operated on at Dept. of Thoracic and Cardiovascular Surgery, Seoul National University Hospital, from May 21st, 1984, to July 6th, 1984. They were 28 males and 24 females including 21 acyanotic congenital heart diseases, 21 cyanotic congenital heart diseases, and 10 acquired valvular heart diseases. In general, preoperative serum ionic calcium was around the normal level, but those of immediate postoperative day and postop-first day were decreased subnormally with significance [P<0.05 vs. preop.]. From postop-third day, serum ionic calcium was returned to normal range. No significant difference was noticed in subgroups divided by 10 Kg of body weight and by the methods of myocardial protection. But the change of serum ionic calcium in the patients with prolonged pump time over 90 minutes was remarkable and the values were as follow; on immediate postop-day 1.780.18 mEq/L vs. 1.970.20 mEq/L [P<0.005],on postop-first day, 1.940.20mEq/L vs. 2.060.12 mEq/L [P<0.025], on postop-third day, 2.030.11mEq/L vs. 2.150.13mEq/L [P<0.01], and on postop-seventh day, 2.030.09mEq/L vs. 2.190.11mEq/L [P<0.005]. In summary, the serum ionic calcium was lowered after extracorporeal circulation and even severer degree according to the prolongation of bypass time. So, after extracorporeal circulation esp. in the cases with prolonged bypass time, early correction of lowered serum ionic calcium would be helpful to the postoperative hemodynamics.

• 한국항공우주학회지
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• 제34권3호
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• pp.22-30
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• 2006

본 논문은 초소형 비행체 날개 주위의 공기흐름 조절을 위한 IPMC 작동기로 구동되는 ZNMF 펌프의 체계적인 설계 및 해석 기법을 소개한다. IPMC는 낮은 인가전압에서 큰 굽힘 변위를 발생시키며, 공기 중에서도 작동이 가능하고, 작은 크기로 손쉽게 제작할 수 있기 때문에 소형 펌프의 작동 막으로 매우 적합한 재료이다. 본 연구에서는 수치해석 기법을 이용하여 최대 작동 체적을 발생시키는 IPMC 작동 막의 최적 형상을 찾고, 이러한 최적형상에 기초하여 슬롯을 갖는 ZNMF 펌프를 설계하였다. 이후 초소형 비행체의 비행속도, 펌프 작동 막의 구동 주파수(~ 40 Hz), 슬롯을 통과하는 공기의 속도 등을 이용하여 무차원화 된 진동수와 모멘텀 계수를 구하였고, 설계된 ZNMF 펌프가 초소형 비행체 날개의 공기흐름 조절에 적용이 가능함을 보였다.