• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.33 no.4
• /
• pp.417-424
• /
• 2009

A micro-mixer with a quasi-active rotor was fabricated, and mixing characteristics were evaluated. The proposed micro-mixer combines an active type micro-mixer with a passive type micro-mixer. The micro-rotor, which is a moving part of an active type micro-mixer, is added in a micro-chamber of a passive type vortex micro-mixer. The rotor rotated by inflows tangent to a chamber, causing strong perturbations. The micro-mixers were fabricated using photosensitive glass. Mixing efficiency of the micro-mixers was measured using an image analysis method. Mixing efficiency and characteristics of the micro-rotor mixer were compared with the vortex micro-mixer without a rotor. Mixing efficiency was reduced as Reynolds number increased at a low Reynolds number due to decrease of residence time. Mixing efficiency at higher Reynolds number, on the other hand, was improved even though residence time decreased since the contact surface between fluids increased by twisted flow. The perturbation induced by rotating rotor at greater than Re 200 improved the efficiency of the rotor mixer.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.14 no.11
• /
• pp.1198-1206
• /
• 2003

In this paper, a MMIC waveguide mixer module based upon the novel suggested mode converter for wave-guide-to-microstrip transition was fabricated and measured. The insertion and return losses of the mode converter was optimized by compensating the discontinuity effect between ridge and microstrip with the modification of 50 $\Omega$ microstrip line pattern. Due to the low loss nature of the mode converter, a millimeter wave MMIC mixer chip can be successfully applied as a waveguide module for mmW waveguide communication system. The measured results of the module showed the successful MMIC chip application in waveguide and the negligible degradation of the supplied chip specification.

• Journal of the KSME
• /
• v.42 no.4
• /
• pp.42-45
• /
• 2002

이 글에서는 카오스의 이론적인 관점에서 성공적이라 할 수 있는 3차원 유동의 적용 예 중에서 산업적으로 관심의 대상이 될 수 있는 파이프 유동에서의 혼합증진, 혼합탱크 내의 혼합증진, 단축압출기에서의 혼합증진, 그리고 마이크로 채널 유동에서의 혼합증진 등 네 가지 유동에 대해 소개하도록 한다.

• 한국가시화정보학회:학술대회논문집
• /
• 2002.11a
• /
• pp.45-48
• /
• 2002

To investigate the flow related to the mixing, micro PIV measurements were performed in the middle plane of the channel. A passive micro mixer analyzed in this work has been designed in the shape of a three-dimensional microchannel and fabricated with PDMS molding process by KAIST. The mixing performance was evaluated for different flow rates using phenolphthalein and sodium hydroxide solutions. Results show that mixing is enhanced by the increase of flow rate, which yields stronger secondary flows with helical streamlines.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.32 no.8
• /
• pp.624-632
• /
• 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.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2006.05a
• /
• pp.539-540
• /
• 2006

It is so difficult to small amounts of two or more fluid species into single in microchannel because flows are usually laminar. In this regard multilamination micro mixer including recirculation zone is presented. Alternating feed micro channels make multilamination and converging-diverging channels form recirculation zone. Multilamination with geometric focusing decreases diffusion path ana recirculation zones make vortex. In this paper flow patterns and mixing properties of multilamination micro mixer including recirculation zone were investigated by Computational Fluid Dynamics (CFD). The CFD results provided qualitative information on mixing.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2007.06a
• /
• pp.725-726
• /
• 2007

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2005.05a
• /
• pp.84-84
• /
• 2005

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2006.10a
• /
• pp.617-618
• /
• 2006

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.26 no.6
• /
• pp.533-539
• /
• 2015

In this paper, we designed a reconfigurable mixer for microwave broadband receiver. The proposed mixer using a anti-parallel diode is operated as a fundamental mixer or sub-harmonic mixer with respect to a control voltage. A fundamental mixer with a control voltage show a conversion loss of -10 dB, 1 dB compression point of 2.0 dBm at X-band/ Ku-band. On the other hand, it is performed as a sub-harmonic mixer with a conversion loss of -17 dB, 1 dB compression point of 2.0 dBm at Ka-band.