• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.211-215
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• 2005

Microsystems combine several microcomponents, optimized an entire system, to provide several specific technical functions by the shape of the microstructure. Microfabrication and micromachining techniques have played the key role in the fast development and commercialization of microsystems. Microreaction technology based on microsystems is a powerful tool for the evaluating new process and reaction pathways in chemical engineering. Because of the small characteristic dimensions of microreaction devices, mass and heat transfer processes are enhanced and, in addition, reaction conditions can be precisely controlled for optimizing yield and selectivity. The paper will report on the mixer design principle and explore several application fields of microreaction technology in the chemical synthesis

• 한국가시화정보학회지
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• 제4권1호
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• pp.31-40
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• 2006

In this study a newly designed electro-osmotic micro-mixer is proposed. This study is composed of a channel and metal electrodes attached locally on the side wall surface ultimately to control the mixing effect. To obtain the flow patterns, numerical computation was performed by using a commercial code, CFD-ACE. The fluid-flow solutions are the cast into studying the characteristics of stirring in terms of the mixing index. It was shown that the local control of the electric potential can indeed contribute to the enhancement of mixing effect.

• 대한기계학회논문집A
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• 제32권8호
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• pp.624-632
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• 2008

In this research, we developed new PDMS-glass based microbiochip consisted of the micromixer and microreactor for DNA ligation. The micromixer was composed of a straight channel integrated with nozzles and pillars, and the microreactor was composed of a serpentine channel. We coated the PDMS chip surface with the 0.25wt.% PVP solution to prevent the bubble generation which was caused by the hydrophobicity of the PDMS. The new micomixer was passive type and the mixing was enhanced by a convective diffusion using the nozzle and pillar. The 10.33mm long micromixer showed the good mixing efficiency of 87.7% at 500 l/min flow rate. We could perform the DNA ligation successfully in the microbiochip, and the ligation time was shortened from 4 hours in conventional laboratory method to 5 min in the microbiochip.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2005년도 추계학술대회 논문집
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• pp.107-110
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• 2005

In this study a newly designed and electro-osmotic micro-mixer is proposed. This design is comprised of a channel and metal electrodes attached in the local side wall surface, To investigate the flow patterns a numerical method is employed. To obtain the flow patterns numerical computation are performed by using a commercial code, CFD-ACE. The fluid-flow solutions are then cast into studying the characteristics of stirring with aid the Mixing index. Focus is given the effect on the electro osmotic flow characteristics under the curvature variation in the microchannel with the local of the electric field

• 한국전산유체공학회지
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• 제11권4호
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• pp.101-106
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• 2006

In the microfluidic devices the most important thing is mixing efficiency ol various fluids. In this study a newly designed miler is proposed to enhance the mixing effect with the purpose to apply it to microchannel mixing in a short future. This design is composed of a channel with cross baffles periodically arranged on the both bottom and top surfaces ol the channel. To obtain the yow patterns, the numerical computation was performed by using a commercial code, ANSYS CFX 10.0. To evaluate the mixing performance, we computed Lyapunov exponent and obtained Poincare sections. it was shown that our design provides the excellent mixing effect.

• 대한기계학회논문집B
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• 제27권7호
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• pp.901-908
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• 2003

Numerical study on stirring characteristics in a microchannel with blocks arranged periodically has been performed. Viscous flows through the microchannel is simulated three-dimensionally using a commercial code, FLUENT 6.0. Focus is given to the effect on the stirring characteristics of the geometric factors including the pitch, height and angle of the block arrangement. The numerical results at low Reynolds numbers show that the particles' trajectories in the microchannel heavily depend on the block arrangement. A nonlinear dynamical tool, i.e. Lyapunov exponent, was used in analysing the mixing effect. It was found that the mixing is the most effective at a certain combination of parameter values.

• 대한기계학회논문집B
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• 제33권5호
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• pp.311-317
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• 2009

Due to extremely small device size and velocity scale, mixing in microchannel take place very slowly by way of molecular diffusion transport. Mixing enhancement becomes a central issue in microfluidics for biomedical and chemical applications. In this work, The optimization results and validation through experiment and fabrication. In this efficient micromixer design, it is essential to evaluate mixing efficiency with good precision. Mixing efficiency for Y-channel micromixer is measured by fluorescence intensity using LIF(Laser Induced Fluorescence) Confocal Microscope. The Y-channel micromixers are fabricated with polydimethylsiloxane(PDMS). Nile Blue A is injected into the micromixer as a fluorescence dye for measuring of fluorescence intensity by He/Ne laser. Throughout the experiments and computer simulation, accurate mixing efficiency evaluation process for a PDMS Y-channel micromixer is established.

• Journal of Advanced Marine Engineering and Technology
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• 제21권4호
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• pp.356-363
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• 1997

Many research works have been carried out to investigate the factors governing the performance of diesel engine. The area of the study has been focused on reducing both of NOx and smoke because of many difficulties to reduce them simultaneously in diesel engines. One of the efforts is an application of EGR technology to reduce NOx emission, which is very effective, but increases other emissions and makes fuel economy worse. In order to solve the problem, EGR is employed with water emulsified fuel and tested in this paper. Emulsified fuel is produced by centrifugal mixer and the amount of water is controlled by water injector and pulse generator, and EGR rate is controlled with 6-step control valve. The chamber pressure, fuel consumption and emissions are measured with various values of both EGR and water mixing rate, The results show that NOx emission is reduced much rather and smoke is also reduced simultaneously.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1016-1020
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• 2003

In this paper, we present a technology of producing anew chaotic micromixer, named Micromixer with Arranged Blocks(MAB), and the experimental result of the mixing performance. Chaotic mixing was successfully achieved by introducing periodic perturbation in the field of the channel flow by means of slanted blocks. The MAB was made by an RP(Rapid Prototyping) technology. We performed flow visualization experiments for the quantification of the mixing performance with the MAB. Lyapunov exponent was measured to be 0.3557 and 0.1305 for the block height 0.8 and 0.2 times the channel width.

• 수산해양기술연구
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• 제25권4호
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• pp.200-208
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• 1989

200MHz ZnO변환기를 이용하여 초음파 현미경을 제작하여, 도미비늘을 화상화하고 광학현미경에 의한 사진과 비교하였다. 그 결과 광학적 반사에 의한 표면의 화상과 초음파의 기계적 탄성적 표면하 반사에 의한 화상에는 다소 차이가 있음을 확인하였다(Fig. 13 및 14). 초음파 현미경은 고체재료 또는 생물조직 상(10(12)등 여러 가지 생물연구 등의 응용이 계획되고 있으며, 특히 초음파 의학의 분야는 그 활용이 눈부실 것으로 예측된다. 초음파 현미경의 제작 그 자체보다, 이것을 도구로 하여 여러 가지 학술적, 기술적 성과가 기대되기 때문에 이 분야의 기초연구가 더욱 중요하게 생각되며 첨단산업분야에서도 비파괴검사 초음파 micro spectroscopy(U.M.S)등과 같은 물질의 탄성적 성질을 micro scale로 계측할 수 있는 등, 많은 활용이 있을 것이 예상된다. 또 초음파 현미경의 방법도 여러 가지이며, 이것을 계측수단으로 일반화하는 문제도 연구할 필요가 있다. 앞으로 광학이나 전자장치 등과 함께 급속한 발전이 기대된다.