• 대한기계학회논문집A
• /
• 제33권3호
• /
• pp.261-264
• /
• 2009

We present a three-dimensional (3D) particle focusing channel using the positive dielectrophoresis (pDEP) guided by a dielectric structure between two planar electrodes. The dielectric structure between two planar electrodes induces the maximum electric field at the center of the microchannel, and particles are focused to the center of the microchannel by pDEP as they flow from the single sample injection port. Compared to the previous 3D particle focusing methods, the present device achieves the simple and effective particle focusing function without any additional fluidic ports and top electrodes. In the experimental study, approximately 90 % focusing efficiency were achieved within the focusing length of 2mm, on both x-z plane (top-view) and y-z plane (side-view) for $2{\mu}m$-diameter polystyrene (PS) bead at the applied voltage over 15 Vp-p (square wave) and at the flow rate below 0.01 ${\mu}l$/min. The present 3D particle focusing channel results in a simple particle focusing method suitable for use in integrated microbiochemical analysis system.

• 한국압력기기공학회 논문집
• /
• 제7권1호
• /
• pp.1-8
• /
• 2011

Advanced SITs of the evolutionary PWRs have the advantage that they can passively control the ECC water discharge flow rate. Thus, the LPSI pumps can be eliminated from the safety injection system owing to the benefit of the advanced SITs. In the present study, a passive sealing plate was designed in order to overcome the shortcoming of the advanced SITs, i.e., the early nitrogen discharge through the stand pipe. The operating principle of the sealing plate depends only on the natural phenomena of buoyancy and gravity. The performance of the sealing plate was evaluated using the VAPER test facility, equipped with a full-scale SIT. It was verified that the passive sealing plate effectively prevented the air discharge during the entire duration of the ECC water discharge. Also, the major performance parameters of the advanced SIT were not changed with the installation of the sealing plate.

• 유체기계공업학회:학술대회논문집
• /
• 유체기계공업학회 2004년도 유체기계 연구개발 발표회 논문집
• /
• pp.635-640
• /
• 2004

The present paper provides the design specifications and working principle of flow controlling vortex valve which will be adopted in a Korean next generation reactor (APR1400). The vortex valve is installed inside the pressurized safety injection tank of APR1400, and it passively controls the water discharge flowrate from the tank. In the present study, the performance of the vortex valve have been evaluated throughout the repeated experiments in the full-scale test facility called VAPER(VAlve Performance Evaluation Rig). Based on the experimental results, it is confirmed that the currently developed vortex valve satisfies the major performance requirements of APR1400 plant design in view of the peak discharge flowrate, pressure loss coefficient, and total discharge duration time. To achieve the highest quality of the experimental results, a quality assurance program for vortex valve tests has been strictly applied.

• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 1998년도 춘계학술발표회논문집(1)
• /
• pp.590-595
• /
• 1998

차세대 원자로(KNGR : Korea Next Generation Reactor)에는 새로운 안전개념으로서 피동형 안전주입탱크(Safety Injection Tank. SIT)의 도입을 고려하고 있는데, 이러한 피동형 유량조절기능은 안전주입탱크내의 유체기구(Fluidic device)인 볼텍스챔버(vortex chamber)에 의해 이루어진다. 볼텍스챔버는 내부에서 발생되는 와류강도에 따라 유동저항의 강도가 달라짐을 이용하여 유량을 피동적으로 조절할 수 있는 유체기구이다. 본 연구에서는 볼텍스챔버의 유동특성을 관찰하기 위하여 소규모 실험장치를 구축하고, 이를 이용하여 실험을 수행하였다. 본 연구는 두 단계로 수행되었다. 제1단계 실험에서는 볼텍스챔버의 기하학적 특성이 안전주입탱크의 안전주입수 방출특성에 미치는 영향에 대한 거시적 관점에서의 연구로서. 볼텍스챔버의 기하학적 변수(유입구 및 방출구의 직경)가 안전주입수의 방출과정에서 발생되는 SIT 내의수위 거동, 안전주입수의 방출유량 특성등에 미치는 영향에 대해 중점적으로 고찰하였다 제2단계 실험에서는 1단계 실험에서 관찰된 안전주입탱크의 여러 가지 방출특성과 볼텍스챔버 내부 유동장의 유동특성과의 관련성을 규명하기 위해 PIV (Particle Image Velocimetry)를 이용하여 볼텍스챔버의 기하학적 변수에 따른 유동장 내부의 국소 유속분포를 측정하였다.

• 한국세라믹학회지
• /
• 제54권6호
• /
• pp.535-538
• /
• 2017

Here we report the tunable electrical properties and chemical sensor of single-walled carbon nanotubes (SWCNTs) network-based devices with a functionalization technique. Formation of highly aligned SWCNT structures is made on $SiO_2/Si$ substrates using a template-based fluidic assembly process. We present a Platinum (Pt)-nanocluster decoration technique that reduces the resistivity of SWCNT network-based devices. This indicates the conversion of the semiconducting SWCNTs into metallic ones. In addition, we present the Hydrogen Sulfide ($H_2S$) gas detection by a redox reaction based on SWCNT networks functionalized with 2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO) as a catalyst. We summarize current changes of devices resulting from the redox reactions in the presence of $H_2S$. The semiconducting (s)-SWCNT device functionalized with TEMPO shows high gas response of 420% at 60% humidity level compared to 140% gas response without TEMPO functionalization, which is about 3 times higher than bare s-SWCNT sensor at the same RH. These results reflect promising perspectives for real-time monitoring of $H_2S$ gases with high gas response and low power consumption.

• 센서학회지
• /
• 제19권4호
• /
• pp.259-270
• /
• 2010

MEMS(micro electro mechanical systems) is a technology for the manufacture hyperfine structure, as a micro-sensor and a driving device, by a variety of materials such as silicon and polymer. Many study for utilizing the MEMS applications have been performed in variety of fields, such as light devices, high frequency equipments, bio-technology, energy applications and other applications. Especially, the field of Bio-MEMS related with bio-technology is very attractive, because it have the potential technology for the miniaturization of the medical diagnosis system. Bio-MEMS, the compound word formed from the words 'Bio-technology' and 'MEMS', is hyperfine devices to analyze biological signals in vitro or in vivo. It is extending the range of its application area, by combination with nano-technology(NT), Information Technology(IT). The LOC(lab-on-a-chip) in Bio-MEMS, the comprehensive measurement system combined with Micro fluidic systems, bio-sensors and bio-materials, is the representative technology for the miniaturization of the medical diagnosis system. Therefore, many researchers around the world are performing research on this area. In this paper, the application, development and market trends of Bio-MEMS are investigated.

• 대한기계학회논문집B
• /
• 제36권5호
• /
• pp.545-551
• /
• 2012

마이크로 유체구조를 기반으로 하는 약물전달장치는 마이크로 유체 채널형상의 간단한 변형만으로 약물분출량을 쉽게 조절할 수 있는 장점이 있다. 그러나 디바이스 제작에 사용된 생분해성 고분자 85/15poly(lactic-co-glycolic acid) (85/15PLGA)의 소수성 기질 때문에 약물전달 장치내부로의 release medium의 유입이 원활하게 이루어지지 않으며 그 결과, 디바이스의 임플랜트 후 초기의 약물 분출에 영향을 줄 것으로 예상된다. 따라서 surfactant인 polyethylene-glycol600 (PEG600)과 Tween80을 이용하여 micro-channel의 표면처리를 한 디바이스와 surfactant를 사용하지 않은 디바이스를 각각 제작하여 약물 전달 실험을 하였으며, 이를 바탕으로 마이크로 유체 채널의 기하학적 형상에 따른 국소 마취제의 일종인 bupivacaine HCl(BHCl)의 분출속도제어를 입증하였다.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2005년도 추계종합학술대회
• /
• pp.755-758
• /
• 2005

This paper describes the novel immunoassay sensing system for a portable clinical diagnosis system. It consists of a bead cage reactor and a CMOS integrated biosensor. It showed the simple and easy antibody coating method on beads by flow-through avidin biotin complex technology in a microfluidic device. It showed just 90 nL sample consumption and good result for the application of alpha feto protein. The bead cage reactor has the role of the antibody coating, antigen binding and enzyme linking for the electrochemical sensing method. The CMOS biosensor consists of ISFET (ion selective field effect transistor) biosensor and temperature sensor for detecting pH that is the byproduct of enzyme reaction. The sensitivity is 8 $kHz/^{\circ}C$ in a temperature sensor and 33 mV/pH in a pH sensor. After filling the 15 um polystyrene beads in bead cage, antibody flowed and reacted to beads. Subsequently, the biotinylated antigen flowed and bound to the antibody and GOD (glucose oxidase)-avidin conjugate flowed and reacted to the biotin of the biotinylated antigen. After this reaction process, glucose solution flowed and reacted to the GOD on beads. The hydrogen was generated by glucose-GOD reaction. And it was detected by the pH sensor.

• 마이크로전자및패키징학회지
• /
• 제17권4호
• /
• pp.1-9
• /
• 2010

삼차원 집적화기술의 현황과 과제 및 향후에 요구되어질 새로운 삼차원 집적화기술의 필요성에 대해 논의를 하였다. Super-chip 기술이라 불리우는 자기조직화 웨이퍼집적화 기술 및 삼차원 헤테로집적화 기술에 대해 소개를 하였다. 액체의 표면장력을 이용하여지지 기반위에 다수의 KGD를 일괄 실장하는 새로운 집적화 기술을 적용하여, KGD만으로 구성된 자기조직화 웨이퍼를 다층으로 적층함으로써 크기가 다른 칩들을 적층하는 것에 성공을 하였다. 또한 삼차원 헤테로집적화 기술을 이용하여 CMOS LSI, MEMS 센서들의 전기소자들과 PD, VC-SEL등의 광학소자 및 micro-fluidic 등의 이종소자들을 삼차원으로 집적하여 시스템화하는데 성공하였다. 이러한 기술은 향후 TSV의 실용화 및 궁극의 3-D IC인 super-chip을 구현하는데 필요한 핵심기술이다.