• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.467-468
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• 2006

In this work, we present the comparison between $d_{31}\;and\;d_{33}$ mode characterization using the PZT micro-actuator for large displacement. The PZT micro-actuator consisted of Si, PZT, and Pt layer on SOI wafer. The electrode shapes were laminated and interdigitated for $d_{31}\;and\;d_{33}$ mode, respectively. In order to characterize the actuation mode, we measured the displacement using laser interferometer. The maximum displacement of d31 mode was $12.2{\mu}m$ at 10V, the actuation characterization of d31 was better than that of d33 mode. We estimated that displacement of d33 mode would be larger than that of d31 above 30V.

• 한국음향학회지
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• 제38권2호
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• pp.184-192
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• 2019

33-모드 링은 31-모드 링에 비하여 결합상수와 압전상수 d가 높기 때문에 광대역 수중 음향 트랜스듀서로 활용성이 높다. 반면 31-모드 링은 축대칭 구조이므로 수치해석 수행시 2차원 축대칭 모델로 간략히 해석이 가능하지만, 33-모드 링은 3차원 수치해석을 수행해야 한다. 즉, 특성 예측을 위해 많은 전산자원과 계산시간이 소요된다. 따라서 33-모드 링의 전기-기계-음향 응답을 모사할 수 있는 등가의 31-모드 링의 유효 물성을 도출할 수 있다면 소나 트랜스듀서 설계 등에 실용적일 것이다. 본 연구에서는 응답 특성을 모사하기 위해 각 링의 전기, 기계 임피던스 및 변환계수(${\phi}$)가 동일하다고 가정하여 등가 31-모드 링의 유효 밀도(${\rho}_{31_{-}eff}$), 컴플라이언스($s^E_{11_{-}eff}$), 압전 상수($d_{31_{-}eff}$), 유전 상수(${\varepsilon}^T_{33_{-}eff}$)를 유도했다. 도출한 유효 물성을 이용하여 진공상태의 링, 수중에서 공기 배킹의 링, 그리고 수중에서 링 내부에 자유롭게 유체가 드나드는 링에 대하여 수치해석을 하였고 이를 33-모드 링의 응답특성과 비교하였다.

• 한국결정성장학회지
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• 제6권2호
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• pp.155-165
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• 1996

Growth of $LiNbO_3$ single crystal by Czochralski method was carried out to study the piezoelectric effects. Piezoelectric coefficients and elastic compliances of the $LiNbO_3$ single crystal were determined by the resonance method of length-extentional mode of bar resonator from the room temperature up to $100^{\circ}C$. Two dielectric constants of $LiNbO_3$ were also determined by measuring the capacitance of the plate specimen. Measured constants were piezoelectric coefficients $d_{15},d_{22},d_{31},d_{33}$ elastic compliances $s^E_{11},s^E_{33},2s^E_{13}+2s^E_{44},s^E_{14}$ and dielectric constants $K^T_{11},K^T_{33}$. As temperature increased, elastic compliances changed very slowly while piezoelectric coeffiecients and dielectric constant $K^T_{33}$ changed very rapidly. Electromechanical coupling constant of zyw ($45^{\circ}C$)-bar was as high as 0.51 in room temperature and nearly constant up to $1000^{\circ}C$. The increase of piezoelectric coefficients was mainly due to the increase of dielectric permittivity.

• Mass Spectrometry Letters
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• 제10권1호
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• pp.38-42
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• 2019

Damaurone D belongs to the genus Rosa and is a traditional medicinal product used for the treatment of depression, inflammation, and infectious diseases. The purpose of this study was to develop a simple liquid chromatography-tandem mass spectrometry method for the detection of damaurone D in rat plasma and to demonstrate its application in pharmacokinetic studies. Damaurone D and berberine (internal standard) were extracted with acetonitrile using a protein precipitation method. Mass transition was monitored in multiple reaction monitoring mode at m/z $323.2{\rightarrow}267.0$ for damaurone D and m/z $336.1{\rightarrow}320.0$ for berberine in positive ion mode. Analytical validation was conducted by evaluating the specificity, linearity, accuracy, precision, matrix effect, extraction recovery, and stability. The calibration curves were linear over 2-1000 ng/mL. The intra- and inter-day precision and accuracy of quality control samples were 4.79-13.33% and 86.23-102.75%, respectively. The matrix effect and extraction recovery were 96.11-98.47% and 96.11-102.25%, respectively. In the pharmacokinetic study after intravenous administration of damaurone D at a dose of 3 mg/kg in rats, the area under the curve and clearance of damaurone D in rat plasma were $16750.26{\pm}2676.10min{\cdot}ng/mL$ and $182.44{\pm}31.36mL/min/kg$, respectively.

• 한국위성정보통신학회논문지
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• 제6권1호
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• pp.28-31
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• 2011

본 논문에서는 d33 모드로 구동하여 우수한 성능을 가지는 RF-MEMS 스위치의 구현을 위한 희생층과 구조층의 조합으로서 DLC와 포토레지스트를 제안하였다. 포토레지스트의 경화현상을 방지하기 위하여 DLC 구조층은 상온에서 RF-PECVD 방법을 이용하여 증착하였다. 그리고 PZT 압전층은 RF 마그네트론 스퍼터링 방법을 이용하여 상온에서 구조층 위에 증착하였으며, 희생층의 제거 후 결정화를 위하여 급속 열처리 (RTA) 장비를 이용하여 후 열처리하였다. PZT의 결정화 과정과 DLC의 기계적 성질의 변화를 다양한 온도조건에 따라 분석한 결과 DLC는 PZT의 결정화 온도까지 영률과 강도면에서 우수한 특성을 나타냄을 확인하였다. 또한 포토레지스트를 사용함으로서 공정을 단순화하고 낮은 비용으로 제작이 가능하였다.

• 대한전자공학회논문지SD
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• 제45권5호
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• pp.33-39
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• 2008

레이저 다이오드의 비선형성으로 인해 발생하는 왜곡성분들을 제거하기 위해 피드포워드 선형화 기법을 적용한 광송신기를 제작하였다. 레이저 다이오드의 파장차이에 따른 광전송 실험을 위해 광 주입 기술을 피드포워드 기법에 적용하여 3차 상호변조 왜곡성분(IMD3)의 크기변화를 측정하였다. 광 전송길이 및 레이저 다이오드의 파장차이로 인해 생기는 위상 부정합 현상을 분석하고 이에 따른 IMD3의 크기변화를 시뮬레이션 및 측정 하였다. 그리고 IMD3의 억제량의 변화를 극복하기 위해 정량적인 위상 가변량을 계산하였으며, 시스템 설계시 고려해야 할 가이드라인을 제시한다.

• Asian-Australasian Journal of Animal Sciences
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• 제26권2호
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• pp.171-177
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• 2013

The aim of the present study was to determine the evidence of post-parturient disorders and backfat loss during lactation in sows raised in tropical areas in relation to their backfat thickness before farrowing and postpartum intravenous supportive treatment. Backfat thickness was measured using A-mode ultrasonography at farrowing and weaning ($25.5{\pm}1.4$ d) in 70 sows. The sows were divided into three groups according to backfat thickness before farrowing, i.e., 15.0 to 20.0 mm (n = 21), 20.5 to 25.0 mm (n = 35), >25.0 mm (n = 14) and were categorized into two groups according to the postpartum supportive treatment, i.e., control (n = 31) and treatment (n = 39). After farrowing, the sows in treatment group received the same medications as in control sows. Furthermore an intravenous supportive treatment with amino acids and vitamins was administered in treatment groups. Rectal temperature and clinical signs of the sows including vaginal discharge, udder problems and appetite were determined at d 0, 1, 2 and 3 of parturition. It was found that, on average, the backfat thickness was $22.4{\pm}3.9$ mm at farrowing and $19.9{\pm}2.9$ mm at weaning. The backfat loss and the relative backfat loss during the lactation period were 2.6 mm and 10.6%, respectively. The sows with a backfat of 15.0 to 20.0 mm before farrowing lost less backfat than those with a backfat of 20.5 to 25.0 mm and >25.0 mm (p<0.05). Sows with a backfat of 15.0 to 20.0 mm had a better appetite on d 1 postpartum than sows with a backfat of 20.5 to 25.0 mm (p = 0.020). The percentage of sows losing backfat >10% during lactation were higher in sows with a backfat of >25.0 mm before farrowing (85.7%) than sows with a backfat of 15.0 to 20.0 mm before farrowing (35.0%) (p = 0.008). The percentage of sows with a reduced appetite on d 1 (90.3% vs 71.8%, p = 0.018) and d 2 (61.3% versus 33.3%, p = 0.005) postpartum in the treatment group was lower than the control group. In conclusion, the backfat thickness of sows at farrowing influenced backfat loss during lactation under hot and humid climates. The intravenous supportive treatment of sows with amino acid and vitamins significantly improved the appetite of postpartum sows.