• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.12
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• pp.1309-1316
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• 2011

This paper presents a high-speed RNA microextractor for the direct isolation of RNA from blood lysate using magnetic oligo(dT) beads. The extraction is performed through lateral magnetophoresis, which is induced by a ferromagnetic wire array inlaid. With this RNA microextractor, more than 80% of the magnetic beads could be separated at a flow rate up to 20 ml/h, and the overall extraction procedure was completed within 1 min. The absorbance ratio of RNA to protein(A260/A280) was greater than 1.7, indicating that the extraction technique yields pure RNA. The feasibility of using this technique in reverse transcription polymerase chain reaction procedures was investigated by cDNA synthesis and PCR processes. The results confirmed that the RNA microextractor is a practical device for easy, fast, and high-precision RT-PCR using minimal amounts of reagent.

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.4
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• pp.387-394
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• 2011

A study on the removal of sulfur dioxide and nitrogen oxide was carried out using a non-thermal nano-pulse corona discharger at different gas temperatures. Pulse voltage with a high voltage of 50 kV, a pulse rising time of about 100 ns, a full width at half maximum of about 500 ns and a frequency of 1 kHz was applied to a wire-cylinder corona reactor. Ammonia and propylene gases were added into the corona reactor as additives with a static mixer. Ammonia addition had less effect on $SO_2$ reduction at the higher temperature because of the retardation of ammonium sulfate formation. However, propylene addition enhanced NO reduction at higher temperature due to increased gas mixture. $SO_2$ was further removed at the mixed $SO_2$ and NO gas due to increased $NO_2$ by the conversion of NO. The addition of ammonia and propylene gases was more highly dominant for the removal of sulfur dioxide compared to the sole pulse corona without the additives. However, the specific energy density per unit concentration of pulse corona as well as propylene additive was an important factor to remove NO gas. Therefore, the specific energy density per unit concentration of 0.04 Wh/($m^3{\cdot}ppm$) was necessary for the NO removal of more than 80% with the concentration ratio of 2.0 for propylene and NO. Hydrogen peroxide was another alternative additive to remove both $SO_2$ and NO in the nano-pulse corona discharger.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.1
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• pp.1-7
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• 2012

This paper introduces the mechanical design, fabrication, and control of a biomimetic fish robot whose driving motions resemble a real fish's flexibility and movement. This robot uses two motors create flexible movement like that of a fish. Several schemes, such as neutral buoyancy, fast underwater swimming, and direction changes, are introduced. The tail of the fish robot is made of a polymer material for flexible movement. The interior of the tail contains a joint and a wire. A sine wave command was applied to the tail to produce motion resembling a real fish swimming, and a buoy control device was installed. The up and down motion of the robot fish was controlled using this device.

• Journal of the Korean Vacuum Society
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• v.18 no.3
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• pp.203-207
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• 2009

Copper is known as a replacement for aluminum wire which is used for semiconductor. Because specific resistance of Cu ($1.67{\mu}{\Omega}$-cm) is lower than that of Al ($2.66{\mu}{\Omega}$-cm), Cu reduce RC delay time. Although melting point of Cu($1085^{\circ}C$) is higher than melting point of Al, Cu have characteristic to easily react with Silicon(Si) in low temperature, and it isn't good at adhesive strength with Si. For above these reason, research of diffusion barrier to prevent reaction between Cu and Si and to raise adhesive strength is steadily advanced. Our study group have researched on W-C-N (tungsten-carbon-nitrogen) Diffusion barrier for preventing diffusion of Cu through semiconductor. By recent studies, It's reported that W-C-N diffusion barrier can even precent Cu and Si diffusing effectively at high temperature. In this treatise, we vaporized different proportion of N into diffusion barrier to research Cu's Electromigration based on the results and studied surface hardness in the heat process using nano scale indentation system. We gain that diffusion barrier containing nitrogen is more stable for Cu's electromigration and has stronger surface hardness in heat treatment process.

• Journal of Sensor Science and Technology
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• v.10 no.5
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• pp.292-303
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• 2001

This work reports the tunneling effects of the lateral field emitters. Tunneling effect is applicable to the VMFS(vacuum magnetic field sensors). VMFS uses the fact that the trajectory of the emitted electrons are curved by the magnetic field due to Lorentz force. Polysilicon was used as field emitters and anode materials. Thickness of the emitter and the anode were $2\;{\mu}m$, respectively. PSG(phospho-silicate-glass) was used as a sacrificial layer and it was etched by HF at a releasing step. Cantilevers were doped with $POCl_3(10^{20}cm^{-3})$. $2{\mu}m$-thick cantilevers were fabricated onto PSG($2{\mu}m$-thick). Sublimation drying method was used at releasing step to avoid stiction. Then, device was vacuum sealed. Device was fixed to a sodalime-glass #1 with silver paste and it was wire bonded. Glass #1 has a predefined hole and a sputtered silicon-film at backside. The front-side of the device was sealed with sodalime-glass #2 using the glass frit. After getter insertion via the hole, backside of the glass #1 was bonded electrostatically with the sodalime-glass #3 at $10^{-6}\;torr$. After sealing, getter was activated. Sealing was successful to operate the tunneling device. The packaged VMFS showed very small reduced emission current compared with the chamber test prior to sealing. The emission currents were changed when the magnetic field was induced. The sensitivity of the device was about 3%/T at about 1 Tesla magnetic field.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.133.2-133.2
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• 2016

차세대 디스플레이로 유연하고 투명한 기능들이 요구되면서 Indium Tin Oxide(ITO)를 대체하기 위한 투명전극 개발 연구가 많이 수행되고 있다. ITO는 높은 투과도와 낮은 저항으로 현재 가장 많이 활용되고 있는 투명전극 소재이지만 유연성이 떨어져 유연 터치 패널 소재로 활용하기 어렵다. 이러한 문제 해결을 위해 ITO 대체 물질로 CNT, Graphene, Metal mesh, Ag nano wire, 전도성 고분자 등의 차세대 투명 전극 소재가 대두되고 있다. 본 연구에서는 메탈 메쉬 전극 소재로 사용하기 위해 Cu 박막 증착 시 플라즈마 표면처리를 통해 밀착력 및 저항을 개선하였다. Cu 금속 박막의 양산화를 위한 공정으로 자체 제작한 Linear Ion Source(LIS)가 부착된 roll to roll 시스템을 적용하여 플라즈마 전처리 공정 및 Ni buffer layer 도입 이후 Cu 박막을 형성하였다. 그 결과 PET 기판과 Cu 박막 사이의 밀착력을 0 degree에서 5 degree까지 향상시킬 수 있었고, 플라즈마 표면처리를 시행함으로써 저항 또한 감소되는 결과를 얻을 수 있었다. 본 연구를 통해서 폴리머 기판 소재에 in-situ로 표면처리 및 Cu 금속 박막을 증착함으로써 금속 박막의 밀착력 및 전기적 특성이 향상되는 공정 기술을 개발하였다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.10
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• pp.1721-1726
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• 2016

4-types of coils were prepared by coating with polyamideimide (PAI) organic/inorganic hybrid. One type was made with original PAI vanish and the other 3-types were made of double layers, that was to say, high flexural PAI layer and high anti-corona PAI/nanosilica (15 wt%) layer. Drying temperature (T/D) were $220^{\circ}C$, $240^{\circ}C$, and $260^{\circ}C$, respectively and rectangular type coil for high-voltage rotating machine was used. DC and AC electrical breakdown tests were carried out in order to study the insulation properties according to T/D temperature and coil curvature (5, 15, and $25mm{\Phi}$). As the curvature increased, electrical breakdown voltage decreased and as T/D temperature decreased, electrical breakdown voltage increased.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10b
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• pp.189-192
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• 2003

The Electro-thermal Explosion Coating (EEC) technique is a new surface treatment technology emerged in recent years. It uses an electrical discharge (with very high voltage from 5 to 30 kV or more) to produce a pulse current with large density inside the material to be deposited, the metal wire undergo the heating, melting, vaporization, ionization and explosion processes in a very short time (from tens ns to several hundreds ${\mu}s$), and the melted droplets shoot at the substrate with a very high velocity (3000 - 4500 m/s), so that the coating materials can be deposited on the surface of the substrate. Coatings with nano-size grains or ultra- fine grains can be formed because of rapid solidification (cooling rate up to $10^6-10^9\;k/s$). Surface of the substrate (about $1-5{\mu}m$ in depth) can be melted rapidly and coatings with very high bonding strength can be obtained.

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.264-265
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• 2000

1차원 반도체 구조인 양자 줄(Quantum Wire)은 새로운 물리 현상의 가능성을 보여줄 것으로 기대된다.$^{(1)(2)}$ 이 구조에서 운반자는 2차원 퍼텐셜에 가두어지므로 1차원 퍼텐셜인 양자 우물에 갇힌 운반자 보다 더 많이 양자화가 이루어져 이 운반자의 상태 에너지는 더 쪼개지며, 양자 줄의 상태 밀도는 에너지 준위에 대해 계단 함수가 아닌 변형된 Dirac $\delta$ 함수꼴을 가진다.$^{(3)}$ 그러나, 1차원 반도체 구조인 양자 줄이 나노(nano) 크기 내에서 만들어져야 하므로, 잘 정의된 양자 줄을 만드는 일은 기술상 매우 어려운 일이다. 양자 우물 구조에서 운반자는 결정을 키우는 방향을 따라 나노 크기의 활성 영역 안에 가두어지게 된다. 양자 줄 구조에서의 운반자는 결정 성장 방향뿐만 아니라 수직인 한 방향에서 각각 나노 크기를 갖는 활성 영역에 가두어져야 한다. 여기에서, 결정 성장 방향과 수직으로 활성 영역을 정의하는 것은, 결정 성장 방향과 평행하게 활성 영역을 정의하는 것보다 어려운 일이다. (중략)

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1183-1183
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• 2015

본 연구에서는 기존 및 개발된 나노반도전에 대한 전계완화역할에 따른 전기적 특성평가를 위해 반도전 종류별로 제작된 이중압출 미니모델케이블을 이용하여 AC 절연파괴시험을 수행하여 절연파괴특성을 확인하였다.