• 전기전자학회논문지
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• 제22권3호
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• pp.874-877
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• 2018

인쇄 회로 기판(PCB: printed circuit board)에는 다수의 표면 실장 부품(SMD: surface mount device)이 장착되어 상호 연결되며, 이들을 연결하는 배선의 전송 특성이 나빠지면 시스템의 성능이 감소하게 된다. PCB와 SMD를 연결하는 패드는 PCB 전송 특성에 큰 영향을 미치기 때문에 패드의 위치도 최적화되어야 한다. 본 논문에서는 패드 정렬이 PCB 전송 특성에 미치는 영향을 시뮬레이션 하였다. 주파수가 비교적 낮은 경우에는 패드 정렬이 PCB 전송 특성에 큰 영향을 미치지 않지만 주파수가 높아지거나 패드 크기가 커질수록 패드 정렬에 따른 영향이 커진다. 따라서 목표 주파수와 패드 크기에 따라 세심하게 패드 정렬을 선택할 필요가 있다. 특히 12~18 GHz의 Ku-밴드 주파수 대역에서는 기존의 중앙 정렬 패드보다 제안하는 측면 정렬 패드가 전체적으로 유리하다.

• 한국전기전자재료학회논문지
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• 제16권11호
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• pp.1023-1028
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• 2003

The field emission characteristics are studied by simulation for carbon nanotube triode structures with a strip-shaped emitter and a gate hole aligned with it. Two structures, one with double-edge and the other with single edge are analyzed. They show good emission characteristics. Emissions of electrons are concentrated on the edges of emitter and the emitted current increases as the distance between emitter and gate decreases. For single-edged emitter, the emitted electrons form a narow strip-shaped beam which has a good directionality. These triode structures have advantages in that they can be easily fabricated and aligned for assembly.

• 전기전자학회논문지
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• 제8권2호
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• pp.161-165
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• 2004

본 논문은 CMOS 에지 완료검출 신호를 이용하여 8bit 웨이브파이프라인 덧셈기를 설게하였다. 이 구조는 클럭이 필요 없이 동작한다. 에지감지후 신호완료를 검출하는 알고리즘회로는 센서회로와 래치로 구성되어있다. 제안하는 구조를 이용하여 8bit 덧셈기의 출력이 거의 같은 시간에 만들어 지도록 정렬된다. 시뮬레이션에서 0.35um CMOS 공정을 사용하여 3.3V 공급전압으로 1GHz 동작을 확인하였다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 추계학술발표대회
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• pp.25.2-25.2
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• 2009

Vertically aligned zinc oxide(ZnO) nanorods (NRs) with different surface morphology were grown by metal organic chemical vapor deposition (MOCVD) on sapphire substrate with different deposition condition. Based on the surface morphology, ZnO nanostructures are divided into three types: nanoneedles, nanonails and nanorods with rounded tip. Variable temperature photoluminescence (PL) have employed to probe the exciton recombination in high density and vertically aligned ZnO Nanorod arrays. Low temperature photoluminescence measurements do not show any significant yellow emission, but the near band edge excitonic emission shows very strong dependence with the surface morphology. The recombination properties are expected to be different due to different surface-to-volume ratio and distribution of potential fluctuations of intrinsic defects.

• 전자공학회논문지A
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• 제33A권7호
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• pp.176-184
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• 1996

To overcome the drawbacks of conventional LDMOSFETs, we propose RESURF EDMOSFETs which can be adapted in varous circuit applications, be driven without charge pumping circuity and thowe threshold voltage can be adjusted. The devices have the diffused drift region formed by a high tmperature process before the gate oxidaton. After the polysilicon gate electrode formation, a fraction of the drift region around the gate edge is opened for supplemental self-aligned ion implantation to obtain self-aligned drift region. This leads to a shorter gate length and desirable drift region junction contour under the gate edge for minimum specific-on-resistance. In additon, a and maximize the breakdown voltage. Also, by biasing the metal field plate, we can reduce the specific-on-resistance further. The devices are optimized by using the TSUPREM-4 process simulator and the MEDICI device simulator. The optimized devices have the breakdwon voltage and the specific-on-resistance of 101.5V and 1.14m${\Omega}{\cdot}cm^{2}$, respectively for n-channel RESURF EDMOSFET, and 98V and 2.75m.ohm..cm$^{2}$ respectively for p-channel RESURF EDMOSFET. To check the validity of the simulations, we fabricated n-channel EDMOSFETs and confirmed the measured breakdown voltage of 97V and the specific-on-resistance of 1.28m${\Omega}{\cdot}cm^{2}$. These results are superior to those of any other reported power devices for smart power IC applications.

• 한국전기전자재료학회논문지
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• 제21권3호
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• pp.260-264
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• 2008

We analyzed the lowering of transmittance due to lateral field effect in the edge of pixel. We studied the method to solve the problem of VA-LCD. It occurred director distortion and transmittance lowering by strong lateral field in the edge of pixel. For analyzing the director distortion and improving the transmittance lowering, we applied the edge pattern to PVA-LCD of cross pattern. As a results, transmittance in the new VA modes were higher than that of conventional VA modes.

• Smart Structures and Systems
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• 제5권6호
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• pp.633-644
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• 2009

A simple method has been developed to detect the bonding condition of active fiber composites (AFC) adhered to the surface of a host structure. Large deformation actuating capability is one of important features of AFC. Edge delamination in adhesive layer due to large interfacial shear stress at the free edge is typically resulted from axial strain mismatch between bonded materials. AFC patch possesses very good flexibility and toughness. When an AFC patch is partially delaminated from host structure, there remains sensing capability in the debonded part. The debonding size can be determined through axial resonance measured by the interdigitated electrodes symmetrically aligned on opposite surfaces of the patch. The electrical impedance and modal response of the AFC patch in part adhered to an aluminum plate were investigated in a broad frequency range. Debonding ratio of the AFC patch is in inverse proportion to the resonant frequency of the fundamental mode. Feasibility of in-situ detecting the progressive delamination between AFC patch and host plate is demonstrated.

• 한국전기전자재료학회논문지
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• 제17권3호
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• pp.305-310
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• 2004

We have studied the optimal phase retardation value of a homogeneously aligned liquid crystal (LC) driven by fringe-field when using the LC with positive dielectric anisotropy. In general, the transmittance of a homogeneous aligned LC cell under crossed polarizer is maximum when a twist angle of LC by in-plane rotation is 45$^{\circ}$ with polarizer and the cell retardation becomes λ/2. However, the device using the LC with positive dielectric anisotropy does not follow this since the degree of rotation of the LC is dependent on electrode position and in addition the LCs tilt up along the fringe-field. At the center of common and pixel electrode, the LC is most twisted around a middle position of a cell whereas at the edge position of pixel electrode, the LC is most twisted near bottom surface of a cell. Consequently, the optimal phase retardation of the device becomes much larger than λ/2 and the transmittance can be described using the combination of the in-plane switching and twisted nematic mode.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 춘계학술발표대회
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• pp.35.1-35.1
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• 2009

Vertically aligned zinc oxide (ZnO) nanorods (NRs) with different surface morphology were grown by metal organic chemical vapor deposition (MOCVD) on sapphire substrate. The films thus prepared were characterized by measuring X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) studies. To study the effect of surface morphology on wettability, the contact angle (CA) of water was measured. It was demonstrated that the CA of the deposited ZnO NRs varied between $104^{\circ}$ and $135^{\circ}$ depending upon the surface morphology. Variable temperature photoluminescence (PL) have employed to probe the exciton recombination in high density and vertically aligned ZnO Nanorod arrays. The low-temperature PL characterizes the dominant near-band-edge excitonic emissions from such nanorod arrays.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 1993년도 한국우주과학회보 제2권2호
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• pp.8-8
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• 1993

Field-aligned(Birkeland) currents of the High-latitude polar region are to the linkage between the solar wind-magnetosphere system and the ionosphere. The characteristics of field-aligned currents at an attitude of 1300 km have been investigated from the KiSat-A satellite magnetometer data recorded at SatRec form March to May 1993. It is found that the po1arity of both east-west and south-north magnetic components becomes reversed and distorted across the poleward edge. We suggest that these changes May occur rule to the Region 1 and Region 2 currents. It is also suggested that the current time resolution which is about 30 seconds, should be improved to prove gradual polarity changes in the polar region. In addition, it is shown how the observational results depend on the longitude in the high-latitude region.