• 한국ITS학회 논문지
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• 제10권1호
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• pp.42-48
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• 2011

본 논문에서는 GaN HEMT (Gallium Nitride High Electron Mobility Transistor) bare-chip을 이용하여 X-대역에서 수동로드 풀(Passive load-pull)을 수행하였다. 열로 인한 특성 변화가 최소화 된 동작 조건을 얻기 위해 드레인 바이어스 전압과 입력 RF 신호를 펄스로 인가하였다. 전자기장 시뮬레이션과 회로 시뮬레이션을 병행하여, 와이어 본딩 효과를 고려하여 드레인 경계면에서의 정확한 임피던스 정합 회로를 구현하였다. 임피던스를 변화시키기 위해 마이크로스트립 라인 스터브의 길이가 조절 가능한 회로를 설계하였다. 펄스 로드 풀 실험 결과 8.5 GHz에서 9.2 GHz 대역에서 최대 42.46 dBm의 출력 전력을 얻었으며, 58.7%의 드레인 효율 특성을 얻었다.

• 한국정보통신학회논문지
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• 제20권12호
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• pp.2417-2424
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• 2016

항공기용 능동위상배열레이다와 같이 한정된 플랫폼에 장착되는 레이다에 사용하는 부품은 소형/경량화 특성이 매우 중요하다. 또한 최근의 능동위상배열레이다는 목표물의 탐지/추적이 가능한 다목적 레이다로 사용하기 위해 수천 개의 송수신모듈이 안테나의 배열형태로 개발되며, 여기에 적용하기 위한 송수신모듈 크기와 무게는 전체 레이다를 설계하는데 중요한 요소이다. 본 논문에서는 국산화 개발된 10W급 RF MEMS 스위치를 이용하여 소형 송수신 모듈을 개발하였고, 기존에 순환기(Circulator)를 사용한 것보다 회로 면적을 약 86.5% 수준으로 줄였다. 개발된 송수신모듈은 주요 전기적 요구 성능을 만족했을 뿐만 아니라, MIL-STD의 환경시험을 통과하여 군수 부품으로 적합함을 확인하였다. 송수신모듈에 적용된 MEMS 스위치는 적응형 수신기 (Adaptive Tunable Receiver), 재구성 가능한 스마트 능동위상배열안테나(Reconfigurable smart active antenna), 광대역 빔조향 안테나 등에도 적용할 수 있다.

• Restorative Dentistry and Endodontics
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• 제24권4호
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• pp.614-622
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• 1999

Recent studies have implicated that more rostral components of the trigeminal spinal nucleus including subnucleus oralis (Vo) in orofacial nociceptive mechanisms. Since there is only limited electrophysiological evidence, the present study was initiated to characterize the receptive field and response properties of malls nociceptive neurons in chloralose/urethan-anesthetized rats. Single neuronal activity was recorded in right subnucleus oralis, and types of nociceptive neurons classified wide dynamic range (WDR), NS (nociceptive specific) and deep nociceptive (D) and the mechanoreceptive field (RF) and response properties were determined. A total of 34 nociceptive neurons could be subdivided into 17WDR neurons, 12NS neurons and 5D neurons. Vo nociceptive neurons had RF involving maxillary and/or mandibular divisions mainly located in the intraoral and/or perioral regions. Majority of Vo nociceptive neurons showed spontaneous activity less than 1Hz. The NS and D neurons activated only by heavy pressure and/or pinch stimuli had high mechanical thresholds compared to WDR neurons activated also by tactile stimuli. Vo nociceptive neurons showed a progressive increase of response to the graded mechanical stimuli. 39% of Vo nociceptive neurons received C-fiber electrical input as well as A-fiber electrical input from their RF, and 45% of them responded to electrical stimulation of the right maxillary first molar. 41% of Vo nociceptive neurons responded to noxious heat applied to their RF, and 18% of them showed an immediate burst of discharges following MO application to the right maxillary first molar pulp. These results indicate that Vo is involved in the transmission of nociceptive information mainly coming from intraoral or perioral region including tooth pulp.

• 한국산림과학회지
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• 제82권4호
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• pp.431-440
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• 1993

한국산(韓國產) 차나무과(科) 6속(屬) 6종(種)을 형태학적(形態學的), 해부학적(解剖學的), Peroxidase 동위효소분석(同位酵素分析) 및 수리학적(數理學的) 분석(分析) 방법(方法)으로 유연관계(類緣關係)를 구명(究明)한 결과(結果)는 다음과 같다. 엽형질(葉形質)에 의한 아과분류(亞科分類)는 평균결합법(平均結合法)과 완전결합법(完全結合法)이 좋은 결과를 보였으며, 주성분(主成分) 분석(分析)에서 기여도(寄與度)가 높은 형질(形質)은 엽폭(葉幅), 엽장(葉長) 등(等)의 잎의 크기였다. 엽맥(葉脈)과 분지각(分枝角)의 크기에 따라 차나무 아과(亞科)는 차나무${\rightarrow}$동백나무${\rightarrow}$노각나무로, 후피향나무아과(亞科)는 사스레피나무${\rightarrow}$비쭈기나무${\rightarrow}$후피향나무로 분류(分類)되었다. 기공(氣孔)의 형태(形態)는 차나무아과(亞科)는 기공(氣孔)의 주위에 부세포(副細胞)가 있는 평행형(平行形)(paracytic type)이고, 후피향나무아과(亞科)는 부세포(副細胞)가 없는 불규칙형(不規則形)(anomocytic type)으로 분류(分類)되었다. Peroxidase 동위효소분석에서 과(科)의 공유(共有)band는 없으나 차나무아과(亞科)는 No.5(Rf. 4.0-4.4)에서, 후피향나무아과(亞科)는 No.7(Rf. 5.7-6.2)에서 아과(亞科)를 구분(區分)할 수 있는 banding pattern이 있었다. 엽형질과 Peroxidase 동위효소분석(同位酵素分析)에 의한 류집분석(類集分析) 결과 유사한 분류군(分類群)을 형성하여 좋은 분류형질로 작용하였다.

• 한국전기전자재료학회논문지
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• 제37권2호
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• pp.208-214
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• 2024

This reports the electrical properties of single-crystal β-gallium oxide (β-Ga₂O₃) vertical Schottky barrier diodes (SBDs) with a different guard ring structure. The vertical Schottky barrier diodes (V-SBDs) were fabricated with two types guard ring structures, one is with metal deposited on the Al₂O₃ passivation layer (film guard ring: FGR) and the other is with vias formed in the Al₂O₃ passivation layer to allow the metal to contact the Ga₂O₃ surface (metal guard ring: MGR). The forward current values of FGR and MGR V-SBD are 955 mA and 666 mA at 9 V, respectively, and the specific on-resistance (R_on,sp) is 5.9 mΩ·cm² and 29 mΩ·cm². The series resistance (R_s) in the nonlinear section extracted using Cheung's formula was 6 Ω, 4.8 Ω for FGR V-SBD, 10.7 Ω, 6.7 Ω for MGR V-SBD, respectively, and the breakdown voltage was 528 V for FGR V-SBD and 358 V for MGR V-SBD. Degradation of electrical characteristics of the MGR V-SBD can be attributed to the increased reverse leakage current caused by the guard ring structure, and it is expected that the electrical performance can be improved by preventing premature leakage current when an appropriate reverse voltage is applied to the guard ring area. On the other hand, FGR V-SBD shows overall better electrical properties than MGR V-SBD because Al₂O₃ was widely deposited on the Ga₂O₃ surface, which prevent leakage current on the Ga₂O₃ surface.

• 생약학회지
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• 제3권1호
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• pp.23-25
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• 1972

Preliminary investigations were carried out to isolate the constituents from the stems of genus Thalictrum. Methanol extracts of eight species from the genus were examined by thin layer chromatography. The author observed three different spots with Dragendorff's reagent in Thalictrum actaefolium, whereas none was detected in Thalictrum tuberiferum and Thalictrum simplex. Various fluorescent colors with different Rf values were detected in all species by UV ray, suggesting that each species may have different components.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 C
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• pp.939-942
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• 1998

This paper presents the process on the construction for the remote distribution pole transformer monitoring system. Especially, this system uses CATV cable as communication media which is located in KEPCO's main distribution line. It has four major components such as sensor for measuring secondary voltage and currents of distribution transformer, RF modem for data modulating/de-modulating, communication media for sending/receiving of data, and pc server for monitoring the results of sensing or computing information. This paper also describes the configuration of these each component's configuration and its functions.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2003년도 추계학술발표대회 요약집
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• pp.245.2-245.2
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• 2003

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2001년도 추계 기술심포지움
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• pp.111-114
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• 2001

Optical transmitter and receiver are the essential components for optical communication. For these components, butterfly type packages are used which are comprised of metal housing, multilayer ceramic inserts, lead and window. In this study, 2.5 Gbps DFB(Distributed -Feedback) LD(Laser Diode) package was fabricated and characterized. Metal housing showed good thermal conductivity (200W/mK) and well matched TCE(6.7ppm/K) with GaAs chip. Ceramic inserts also showed good VSWR(Voltage Standing Wave Ratio) characteristics(<2.0). By brazing technology, all the elements were combined and sealed. RF characteristics of the package mounted on the PWB was also tested.

• 생약학회지
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• 제20권4호
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• pp.227-232
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• 1989

As a part of studies on the quality control of crude drug preparation (So-Shi-Ho-Tang), index components of Glycyrrhizae Radix were identified by TLC and quantified by HPLC. Specific red spot (Rf=0.47) was identified in acid hydrolysate of glycosidic fraction on silica gel plate with benzene/ethyl acetate (1 : 1, v/v). The content of glycyrrhizin was determined by quantification of glycyrrhetinic acid by HPLC on ${\mu}-Bondapak\;C_{18}$ column with $MeOH/H_2O/HAc$ (78 : 19 : 3, v/v). Its recovery rate in the extract granules, compared to the content in the Glycyrrhizae Radix, was $83.3{\pm}0.7%$.