• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.581-582
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• 2007

• Journal of Drive and Control
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• v.18 no.1
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• pp.45-48
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• 2021

• Proceedings of the KIEE Conference
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• 2008.10a
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• pp.119-120
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• 2008

Using the extensional vibration mode of PZT bar, a piezopump is successfully made. The traveling extensional wave along the circumference of the bar is obtained by dividing standing waves which are temporally and spatially phase shifted by 90 degrees from each other. The proposed piezopump is consisted of coaxial cylindrical shells that are bonded piezoelectric ceramic bar.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1824-1827
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• 2005

For application to micro fluid control systems such as ${\mu}TAS$ (Micro Total Analysis Systems) and DDS (Drug Delivery Systems), it is very significant to handle precise and minute flow rates with low pressure pulsation. In this study, a novel valveless piezoelectric pump using peristaltic motion with three disk type PZT actuators is presented. The newly devised pump with an effective size of $70mm{\times}60mm{\times}55mm$ has three actuator layers connected in series from inlet to outlet. The PZT actuator has a maximum displacement of 240 ${\mu}m$ and a maximum force of 1.6 N. When the driving voltage for PZT actuators is sequentially applied with a certain phase shift, the pumping is performed by peristaltic motion of liquid volume. The working fluid is shut off without the driving voltage. Three methods for sequential driving are proposed and experimentally investigated. First and second methods utilize an intermittent sinusoidal waveform with phase shift of $90{\circ}\;and\;120^{\circ}$, respectively. Third method uses a rectangular waveform with phase shift of $90^{\circ}$. A controller with multi-phase shifter is designed and fabricated. Then, frequency and voltage-flow rate characteristics and load pressure-flow rate characteristics are experimentally investigated to verify the validity of the developed pump.

• Proceedings of the Korea Contents Association Conference
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• 2010.05a
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• pp.73-75
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• 2010

1인칭 슈팅 게임인 FPS(First-person shooter)게임은 시각적 사실성이 뛰어난 고급 그래픽이 특징으로 컴퓨터 성능의 향상과 게임 제작 기술의 발전으로 꾸준히 성장해 가고 있다. 하지만 대부분의 FPS 게임은 동일 캐릭터에 무기만 바꾸는 방식의 단조로운 자유도를 제공하며 이로 인해 사용자의 입장에서는 장기간 게임진행시 흥미를 잃기 쉽다. 이러한 단조로운 게임방법을 변화시키고자 1999년 밸브(Valve) 사(社)의 '팀 포트리스(Team Fortress)' 게임은 FPS 게임 사상 최초로 병과 시스템을 도입하여 다양하고 개성 있는 캐릭터 구성으로 큰 주목을 받았다. 이를 분석해 FPS 게임을 개발할 때 다양한 병과 캐릭터가 플레이어에게 얼마나 더 게임에 대한 몰입과 흥미를 주는지 분석하려 한다. 이 분석을 위해 '팀 포트리스'의 후속 작 '팀 포트리스2(Team Fortress 2)'의 병과 캐릭터를 성격 유형 분석에서 보편적으로 많이 쓰이고 사람들에게 친숙한 MBTI (Myers-Briggs Type Indicator) 방식으로 파악하여 각 병과별 캐릭터 설정이 게임 플레이어와의 성격에 따라 얼마나 더 몰입도와 흥미를 줄 수 있는지 도출해 내려한다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.91-91
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• 2009

Piezoelectric micro-pump should contain the physical running parts like check valves for acquiring the unilateral motion of fluid from the alternating motion of actuators. But the check valves raise many problems such as abrasion or exhaustive destruction by the recursive mechanical displacement To solve these problems, we propose a novle type piezoelectric valveless micro-pump using peristaltic motion due to the traveling wave excitation. Proposed pump model is consisted of two piezoelectric ceramic plates, elastic metal body, caps for covering flow path, rubber rings for sealing tightly and disk springs for the pressurization of pump body.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1275_1276
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• 2009

Micropump is very useful component in micro/nano fluidics and bioMEMS applications. Using the flexural vibration mode of PZT bar, a piezopump is successfully made. The PZT bar is polarized with thickness direction. The proposed structure for the piezo-pump consists of an input and an output port, piezoelectric ceramic actuator, actuator support, diaphragm. The traveling flexural wave along the bar is obtained by dividing two standing waves which are temporally and spatially phase shifted by 90 degrees from each other. Fluid is drawn into a forming chamber, eventually the forming chamber closes trapping the fluid therein.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.215-216
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• 2008

Using the extensional vibration mode of PZT ring, a piezopump is successfully made. The PZT ring is polarized with thickness direction. The traveling extensional wave along the circumference of the ring is obtained by dividing two standing waves which are temporally and spatially phase shifted by 90 degrees from each other. The proposed piezopump is consisted of coaxial cylindrical shells that are bonded piezoelectric ceramic ring.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2763-2768
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• 2007

Recently, as the semiconductor production technology develops, there has been growing interest in the cooling system using micro fluid pump. Among the various types of micro fluid pump, the valve-less diffuser/nozzle has been extensively studied in recent years. However, the flat-walled diffuser/nozzle flow has not been clearly looked into due to its non-linear characteristics. In this paper, the flow characteristics of the flat-walled diffuser/nozzle have been analyzed using similitude model and simulations. Similitude models are designed so that the flow pattern is same as that of 1/10 scale flow by using high viscous fluid as working fluid. The results are compared to the simulations. It is shown that the flow characteristics of 2D simulation are different from 3D simulations at high Re region, and the measured pump efficiency is highly dependent on the pressure difference as well as the channel geometry. From these results, the desirable conditions for the efficient pump is discussed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.159-159
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• 2009

Existence of physical moving parts (ex. check valve) produces several problems (mechanical abrasion, deterioration of reliability, limited temperature performances etc.) in driving pumps. To overcome such problems, we proposed a valveless piezoelectric micro-pump which has new type volume transferring mechanism. The proposed micro-pump has a double faced disk type vibrator that can generate peristaltic motion formed by traveling wave in each surface of a disk. This type of micro-pump is able to apply to a fluid supply system that provides two different kinds of fluid simultaneously. In this paper, we propose a simple and novel design of piezoelectric micro-pump that is peristaltically by piezoelectric actuators and allows the removal of the need for valves of other physically moving parts. The finite elements analysis on the proposed pump model was carried out to verify its operation principle using the commercial analysis software.