• 반도체디스플레이기술학회지
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• 제14권2호
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• pp.1-7
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• 2015

In this paper, a new capacitive pressure sensor has been proposed for a displacement measurement. The new sensor is mainly composed of a gap of $5{\mu}m$ and a notch of $1{\mu}m$. And the sensor has the performance as the high sensitivity and capacitance compared with a commercial capacitive sensor. Therefore, the advantages of the new capacitive pressure sensor are good sensitivity in normal range, mechanically robust and large overload protection. The analytical model is induced for confirming the performance of the proposed sensor. In addition, FEM (finite elements method) simulation has been performed to verify the analytical model. Firstly, the displacement characteristics of diaphragm membrane were simulated by the analytical model and FEM in the case of different structure and materials. At last, through this analysis, these simulation results can be predicted the change of the performance when the device parameters are varied. And it is used as a design tool to achieve at a set of performance we desired.

• 한국전기전자재료학회논문지
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• 제29권7호
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• pp.404-407
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• 2016

In this study, to develop low temperature sintering capacitor composition ceramics with the good dielectric properties, $(Ba_{0.86}Ca_{0.14})(Ti_{0.85}Zr_{0.12}Sn_{0.03})O_3$ (BCTZ) ceramics were prepared by the conventional solid-state reaction method. The effects of $B_2O_3$ addition on the dielectric properties and microstructure was investigated. The XRD patterns demonstrated that all the specimens showed Perovskite phase, and secondary phases are indicated in the measurement range of XRD. And also, temperature coefficient of capacitance(TCC) of all the specimen sintered at $1,180^{\circ}C$ showed +3~-56% except for x=0.006. For all the specimens, observed one peak was tetragonal cubic difuse phase transition temperature(Tc), which is located in the vicinity of room temperature.

• 한국광학회지
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• 제12권4호
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• pp.300-304
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• 2001

압전소자에 전압을 가했을 때 길이가 늘어나며 휘어지는 것을 측정하고 보정하는 방법을 제시한다. 압전소자에 부착된 거울에서 반사되는 레이저빔의 각도 변화를 $0.36\mu$rad의 불확도로 측정하여 압전소자가 휘는 각도와 방향을 알수 있는 장치를 구성하였다. 압전소자의 전극을 세부분을 분할하고 축전기를 직렬 연결하여 하나의 전원으로도 각 전극에 인가되는 전압을 달리 조절할 수 있었다. 압전소자가 휘어지는 크기와 방향에 따라 각 전극에 연결되는 축전기의 용량을 달리함으로써 보정 전에 비해 휨을 6.3%로 줄일수 있었다. 휨이 보정된 압전소를 광자감쇠공동의 길이 변조에 이용하였을 때 압전소자가 휘기 때문에 야기되었던 감쇠시간 요동이 효과적으로 제거되는 것을 확인하였다.

• 한국전자파학회논문지
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• 제15권4호
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• pp.368-378
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• 2004

본 논문에서는 finite-extent backed conductor를 가지는 CPW(Coplanar waveguide) 방향성 결합기에서, 방향성의 향상을 위해 접지면과 전송선 사이의 slot 폭을 확장하는 보상구조를 제안하였다. 제안된 구조는 적절한 slot의 길이와 폭을 가질 경우, 결합기에서의 변화되는 정전용량과 추가된 인덕턴스로 인해 각모드의 위상속도 차이가 없어지므로 우수한 방향성 특성을 갖게 한다. 제안된 보상구조를 이용하여 1 ㎓를 중심주파수로 하는 finite-extent backed conductor를 가지는 CPW 방향성 결합기를 보통의 결합도를 갖는 6 ㏈ 결합기와 높은 결합도를 갖는 3 ㏈ 결합기 형태로 구현하였다 설계된 CPW 방향성 결합기는 MoM(Method of Moments) 방식의 EM solver 계산 결과, 중심주파수에서 목적하는 결합도를 가지면서 각각 55 ㏈와 58 ㏈의 우수한 방향성을 가지며, 정합특성 역시 우수하다. 측정결과는 계산결과와 매우 유사하며, 이를 통하여 제안된 보상구조의 유용성을 확인하였다.

• 한국전기전자재료학회논문지
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• 제16권9호
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• pp.783-789
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• 2003

The winding problems of traction motor are the major determinant of motor's life. The root cause of winding failure is gradual deterioration of the insulation due to thermal, electrical, mechanical and environmental stresses. The aging of the insulation reduces the electrical and mechanical strength of the insulation. At same point, a voltage surge or mechanical shock from a traction motor start will fracture or break down the insulation. To achieve the expected life usually requires extensive laboratory evaluation of the insulation systems and the use of accelerated aging tests. There are several nondestructive test available for checking, the condition of motor insulation, the probable extent of aging, and the rate of which aging is taking place. So the insulation characteristics of stator coil were each analyzed by measurement of dielectric loss(tan$\sigma$), capacitance and partial discharge. The method of diagnosis is able to analyze the insulation condition and evaluate the life of the traction motor.

• 한국유기농업학회지
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• 제3권1호
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• pp.11-22
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• 1994

Exposing plant organs to high doses of ionizing irradiation, penetrating into the plant tis-sues and cells, along the track structure of particles, lesions, and sublesions are formed on the molecules and organelles. As a result, disorders in the growth and development as well as chlorophyll-deficiency symptoms occur. The time scale of their reparation, recovery and over compensation during ontogenesis, constitutes a question of high theoretical and practical importanced, with special regard to nuclear fallout. With an aim to model the “ut supra”stated phenomena, the seeds of bean, Echo elit licensed variety, were irradiated by 300 Gy dose of X-ray-irradiation (120 kV:4.5 mA). According to the data obtained, the biosynthesis of photosynthetic pigments, will have been completed by the beginning of flowering. In consequence of the overcompensation of the repairing processes, the organs of plants developed from irradiated seeds, showed a partly differing correlative growth, compared to those of control plants. In order to characterize the vivo response of radiation-injured plants, a new method and approach were used. The changes of the electric capacitance of the plants during their ontogenesis, were continously monitored and recorede via a computer-aided and controlled measurement. In view of the data collected in such a way, the repairing plants may respond more quickly and intensively to the changes of environmental factors.

• 한국표면공학회지
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• 제52권3호
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• pp.130-137
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• 2019

In this study, the cobalt sulfide (CoS) nanosheet on stainless steel as a supercapacitor electrode is synthesized by using a facile successive ionic layer adsorption reaction (SILAR) method. The number of cycles for dipping and rinsing can control the nanosheet thickness of CoS on stainless steel. Field emission-scanning electron microscopy (FE-SEM) showed a layer structure of CoS particles coupled as agglomeration. And x-ray diffraction (XRD) showed the crystallinity of the CoS nanosheet. To investigate the characteristics of the CoS nanosheet electrode as the supercapacitor, analysis of electrochemical measurement was conducted. Finally, the CoS nanosheet of 70cycles on stainless steel shows the specific capacitance ($44.25mF/cm^2$ at $0.25mA/cm^2$) with electrochemical stability of 78.5% over during 2000cycles.

• Current Photovoltaic Research
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• 제2권2호
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• pp.59-62
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• 2014

Minority carrier diffusion length is one of the most important parameters of solar cells, especially for short circuit current density (Jsc). In this report, we proposed the calculating method of the minority carrier diffusion length ($L_n$) in CIGS solar cells through biased quantum efficiency (QE). To verify this method's reliability, we chose two CIGS samples which have different grain size and calculated $L_n$ for each sample. First of all, we calculated out that $L_n$ was 56nm and 97nm for small and large grain sized-cell through this method, respectively. Second, we found out the large grain sized-cell has about 7 times lower defect density than the small grain sized-cell using drive level capacitance profiling (DLCP) method. Consequently, we confirmed that $L_n$ was mainly affected by the micro-structure and defect density of CIGS layer, and could explain the cause of Jsc difference between two samples having same band gap.

• 한국진공학회지
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• 제11권3호
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• pp.135-140
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• 2002

본 논문에서는 p-type (100)Si, (100)MgO 그리고 MgO/si 기판 위에 RF Magnetron sputtering 법으로 $Ba_{0.5}Sr_{0.5}TiO_3$(BST)박막을 증착하였다. BST 박막 증착 후 RTA(Rapid Thermal Annealing)를 이용하여 $600^{\circ}C$에서 산소분위기로 1분간 고온 급속 열처리를 하였다. 증착된 BST박막의 결정화를 조사하기 위해 XRD(X-Ray Diffraction)측정을 한 결과 모든 기판에서 (110) $Ba_{0.5}Sr_{0.5}TiO_3$(의 주피크가 관찰되어졌고, 열처리 후 재결정화에 기인하여 피크 세기가 증가함을 관찰할 수 있었다. Al 전극을 이용한 커패시터 제작 후 측정한 C-V(Capacitance-Voltage) 특성에서 각각의 기판에서 측정된 커패시턴스 값으로 계산된 유전율은 120(bare Si), 305(Mgo/Si) 그리고 310(MgO)이었다. 누설 전류 특성에서는 0.3 MV/cm이내의 인가전계에서 1 $\mu\textrm{A/cm}^2$ 이하의 안정된 값을 보여주었다. 결론적으로 MgO 버퍼층을 이용한 기판이 BST 박막의 증착을 위한 기판으로써 효과적임을 알 수 있었다.

• 한국전자파학회논문지
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• 제29권5호
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• pp.359-365
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• 2018

본 논문에서는 기존 단품 Printed Spiral Coil(PSC)의 외부 노이즈 결합의 저감을 위한 차폐 구조와 차폐된 PSC의 대역폭 개선을 위한 설계법이 제안되었다. 차폐 구조가 적용될 경우, PSC와 차폐 구조 사이의 기생 커패시턴스에 의한 공진현상으로 인해 단품 PSC 대비 전달함수 대역폭에 한계를 가지게 되며, Radio-Frequency Interference(RFI) 노이즈 원으로 가정된 $50{\Omega}$ 마이크로스트립 라인과의 전달함수 시뮬레이션을 통해 이를 확인하였다. 차폐된 PSC의 등가회로 모델을 통해 대역폭을 개선할 수 있는 방안을 제시하고, 3D field simulation을 이용한 사례 연구를 통해 방안의 타당성을 검증하였다. 제시된 방안을 기반으로 차폐 구조가 적용된 PSC 설계의 최적화를 수행하였으며, 측정 검증을 통해 전달함수가 보존되는 범위 내에서 전달함수의 대역폭이 개선됨을 확인하였다.