• 한국음향학회지
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• 제16권2호
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• pp.89-94
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• 1997

아황산가스를 감지하기 위해 새로운 CdS 무기박막을 이용한 표면탄성파 센서를 구현하였다. LiTaO$_3$ 단결정 압전기판에 중심주파수 54MHz인 두 개의 SAW 소자 및 발진기를 제작하였으며 아황산가스가 흡착, 탈착할 수 있는 감지막을 지연선 상에 증착시키고 다른 변수로부터의 반응을 보상하기 위해 이중지연선 구조로 제작하였다. CdS 박막은 초음파 노즐을 이용하여 분무 열분해법을 이용하여 증착하였다. 실험결과 표면탄성파 센서는 아황산가스의 농도를 0.25 ppm 까지 검출할 수 있으며 20 ppm 이내의 안정도 및 5분 이내의 빠른 반응시간을 보였다. 또 가스감응 실험의 반복을 통해 센서의 반복성을 확인함으로써 본 연구에서 개발한 센서가 이황산가스 감지용 센서로 사용될 수 있음을 확인하였다. 향후 계획으로 CdS 박막 증착시에 적절한 원소를 첨가하여 박막의 반응성을 증가시키며 또한 표면탄성파 소자의 중심주파수를 증가시켜 센서의 가스감응성을 높이고자 하였다.

• 한국결정성장학회지
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• 제15권6호
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• pp.234-238
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• 2005

[ $Cl_2/Ar$ ] 유도결합 플라즈마(ICP)내의 플라즈마 조성, 이온 flux 및 이온 에너지가 $La_3Ga_5SiO_{14}$ 단결정 wafer의 식각속도, 표면 양상 및 화학량론적 조성에 미치는 영향을 조사하였다. 비교적 높은 ICP source power$({\sim}1000W)$ 또는 높은 $Cl_2$ gas 유량 비율 조건으로부터 최고 약 $1600{\AA}/min$의 실용적이고 조절이 용이한 식각속도를 확보하였다. 식각된 $La_3Ga_5SiO_{14}$ 표면은 식각 이전과 비슷하거나 더 낮은 표면 조도 특성을 나타내었으며 식각 공정 전, 후 표면의 화학량론적 조성에 있어서의 변화는 없는 것으로 조사되었다.

• 한국기계가공학회지
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• 제15권5호
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• pp.100-108
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• 2016

In various industries, many researches studies have been done in using nano thin film fabrication technology. In the field of printed electronics, various electronic devices can be fabricated using a direct printing process of on multiple functional materials. It has the advantages of low prices, environment-friendly environmentally friendly, flexibleility, large scale, mass production produced, simple process and so on. In this study, a viable thin film fabrication technology has beenwas introduced using the surface acoustic wave mechanism for thin film deposition. Fabrication of thin films using organic, inorganic and composite of organic/inorganic materials have been were analyzed through the experimental research. In this experiment, organic material MEH:PPV, inorganic material ZnO and composite material MEH:PPV/ZnO have been depo sited as thin films.

• 전기학회논문지
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• 제62권12호
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• pp.1730-1736
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• 2013

Slanted and chirp interdigital transducer(IDT) configurations were studied for generating the surface acoustic wave(SAW) with wide bandwidths on a piezoelectric substrate. These devices can be applied to manipulate optical path of light along the waveguide, ultimately used for optical switches and holographic image implementation. Prior to fabrication, the coupling of modes(COM) modeling and simulation were performed to extract optimal design parameters. The optimally designed wideband device showed wide bandwidth of 30MHz, low insertion loss of -25dB, and abrupt side suppression ratio (SSR). Several design conditions were determined during device implementation, such as slanted angle, aperture length, number of fingers, and central frequencies of IDTs. These factors were experimentally analyzed and described in details in this paper.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1384-1385
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• 2008

본 논문에서는 내장된 수동형 트리플렉서와 듀얼 밴드/트라이모드 RF 모듈을 PCB에 내장시켜서 북미향 CDMA용 부품으로 제작하였다. 수동형 트리플렉서는 모든 수동 소자들을 다층 PCB 기판 안에 내장시키고 그 위에 GPS용 SAW 대역통과필터를 이용하여 설계 및 제작하였다. 8개의 인덕터와 커패시터로 이루어진 수동 회로는 다이플렉서와 병렬 공진기, 임피던스 매칭 회로로 구성되어 있다. CDMA용 듀얼밴드/트라이모드 RF 모듈은 트리플렉서와 CDMA, PCS용 듀플렉서를 테스트 보드 위에 조합하여 제작하였다. 측정된 주파수 특성들은 시뮬레이션 값과 비교적 일치하였다. 트리플렉서와 듀얼 밴드/트라이모드 RF 모듈은 각기 $3{\times}4mm^2$와 ${7\times}7mm^2$의 작은 크기였다. 설계 및 제작된 소자들은 고성능과 경박단소화, 저가화 등의 이점이 있기 때문에, 북미향 CDMA용 단말기의 응용부품에 적용될 수 있을 것으로 예상된다.

• Korean Chemical Engineering Research
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• 제49권2호
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• pp.224-229
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• 2011

본 연구에서 탄성표면파(SH-SAW) 디바이스의 지연선에 코팅된 골드 위에서 면역 글로불린 G(IgG) 검출을 위한 SH-SAW 센서를 개발하고자 하였다. 실험결과, 금표면 위에 anti-MIgG 혼합물을 일관되게 고정시킬 수 있었다. G-anti MIgG 혼합물과 blocking buffer를 이용한 골드 표면 위에 고정화 하였을 때 주파수 변위를 측정한 결과, G-anti MIgG 는 초기 주파수에서 75.1 kHz 주파수 변위를 보였으며 blocking buffer는 215.7 kHz의 주파수 변위를 보였다. 100 MHz 센서에서 MIgG의 농도가 25, 50, 75, 100 ${\mu}g$일 때 46.3, 127.45, 161.21, 262.39 kHz 주파수 변위를 보였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.744-749
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• 2005

In this paper, a lens actuator for mobile devices is proposed using stack type piezoelectric materials. In general, the deformation of PZT actuators is not enough for lens motion when the allowed voltage is applied. The small stroke problem can be solved by accumulating a lot of small displacements in high frequency. In this paper, a new inch-worm type model for focusing actuator is suggested based on the interaction of inertial and frictional forces. Theoretical analysis and simulation using ANSYS are performed to verify the feasibility of the inch-worm PZT actuator model. Various types of clamps are considered to determine the effect of frictional force on the motion, and appropriate clamp-actuator models are proposed. The proposed models are experimentally verified and the experimental results show high correspondence with theoretical and simulated values. The inch-worm type focusing actuator enable a large stroke with 7.79 mm/sec with 10kHz and 10V.

• 산경연구논집
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• 제15권5호
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• pp.17-27
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• 2024

Purpose: The renminbi (RMB) has appreciated alongside the elevation of China's economic status, leading to increased exchange rate volatility. Moreover, China's medical industry saw a surge in import and export trade volume, with trade related to epidemic prevention and control in the medical sector significantly increasing its share. The medical device trade, in particular, occupies a substantial portion of this trade. Research design, data and methodology: This paper focuses on the import and export value of medical devices in the medical industry as a case study to explore the impact of RMB exchange rate fluctuations on the import and export trade of the medical industry during the pandemic. Additionally, it investigates whether the import and export trade of the medical industry can be a contributing factor to the fluctuations in the RMB exchange rate. Results: Through an empirical study on the import and export values of medical devices in the medical industry over the past three years, as well as the RMB exchange rate, this paper establishes a VAR model and conducts a series of tests including stationarity tests and cointegration tests. Conclusions: The conclusion is that fluctuations in the RMB exchange rate have a long-term impact on China's medical industry's import and export trade.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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• pp.509-511
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• 1994

Cycloconverters can be classified into two types by the main circuit configuration. One is the non- circulating current type required the dead time the other is circulating current type which has the circulating current reactors. The switching devices were highly stressed by the load voltages during dead time on non-circulating current type operation and the circulating currents on circulating current type operation. The overcome those problems, this paper proposes the switching patterns for the partial and the non circulation current type. The PWM methods, which are saw wave comparing method and load current integrating value comparing method, are presented.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 영호남학술대회 논문집
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• pp.131-134
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• 2000

Electroluminescent[EL] from conjugated polymers has recently received great attention because polymer light-emitting diodes[LEDs] clearly have potential for applications such as large-area displays. The operation of polymer LEDs is based on double injection of electrons and holes from the electrodes, followed by formation of excitons whose radiative decay results in light emission at wavelength characteristic to the material In this paper, we fabricated the single layer EL device using poly(3-octylthiophene)[P3OT] as emitting material. The orange-red light was clearly visible in a dark room Maximum peak wavelength of EL spectrum saw at 640nm in accordance with photon energy 1.9eV. And we know that ionization energy of P3OT is 4.7eV from the cyclic voltammetry.