• Journal of the Optical Society of Korea
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• v.2 no.2
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• pp.74-79
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• 1998

The use of a fiber Fabry-Perot interferometer (FFPI) as an optical current transducer is demonstrated. A conventional inductive pickup coil converts the time-varying current I(t) being measured to a voltage waveform V(t) applied across a piezeolectric strip to which the FFPI is bonded. The strip experiences a longitudinal expansion and contraction, resulting in an optical phase shift ${\phi}(t)$ in the fiber proportional to V(t). This phase shift is measured using a frequency-modulated semiconductor light source, photodiodes to monitor the reflected light from the FFPI and the laser power, and a digital signal processor. Calibration routines compute V(t) and I(t) from the measured phase shift at a l KHz rate. Response to 60 Hz ac over the design range 0-1300A rms is characterized Transient response of the FFPI transducer is also measured.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.132-137
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• 2001

Miniaturized specimen technology is useful to characterize the mechanical behavior using a minimum volume of material, because it is almost impossible to sample the conventional specimen for the fracture toughness test without damage to equipment. Test material was 1Cr-1Mo-0.25V steel which was widely used for turbine rotor material. Two kinds of miniaturized impact specimens were prepared, i.e., miniaturized specimen with side groove and without side groove. The correlation between ductile brittle transition temperature(DBTT) of full size impact specimen and that of miniaturized impact specimen was made. The characteristics of miniaturized impact specimens technique as well as fracture stress were discussed. Finally, we concluded that the characteristics of fracture stress change on aging time were similar to that of DBTT.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.483-485
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• 2007

The active-matrix field emission display (AMFED) was fabricated by integrating carbon nanotube emitters on a-Si thin-film transistors. Also, the tapered macro-gate was adopted for high immunity to a high anode voltage and strong electron beam focusing. The fabricated AMFED was successfully driven with a low voltage of below 15 V.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.842-845
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• 2012

의료기기는 헬스케어 서비스를 위한 필수요소로 최근 의료와 관련된 스마트폰 애플리케이션의 증가와 함께 스마트폰과 연결되는 의료기기를 활용한 스마트 헬스케어가 대두되고 있다. 이러한 스마트 헬스케어는 현재 ISO/IEEE 11073 표준을 통해 의료기기와 게이트웨이를 연결하여 임상정보를 전송하고 게이트웨이는 HL7 CDA 표준 문서를 통해 전자 건강 기록 및 개인 건강 기록 시스템, 임상 워크플로우 및 임상 의사 결정 지원 시스템과 같은 유형의 의료 서비스 시스템과 연동하는 솔루션이다. ISO/IEEE 11073은 DIM(Domain Information Model)이라는 정보 모델을 기반으로 하며 HL7 v3인 CDA는 RIM(Reference Information Model)이 있기 때문에 상이한 인터페이스간의 매핑 매커니즘을 필요로 한다. 이에 본 논문에서는 스마트폰 환경에서 의료 응용 애플리케이션에서의 효율적인 의료기기 데이터 운용을 위해 RMIM(Refined Message Information Model) 기반의 IEEE 11073 DIM/HL7 v3 RIM 표준 인터페이스 변환 방법을 제안한다.

• Korean Journal of Medicinal Crop Science
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• v.8 no.2
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• pp.123-128
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• 2000

This study was carried out to determine factors affecting on the mass propagation of Rehmannia glutinosa seedlings in bioreactor culture. Air-lift type bioreactor was more compatible to shoot formation than stirrer type. Fifty grams(90 stem explants) of inoculum in 1.5L medium was placed into 2.5L bioreactor with aeration rate of 0.5 v.v.m., which was proper for effective shoot formation. Adding MES as pH buffer to culture medium increased the numbers of shoot formation. Adding 5g/l of anti-vitrifying agent into culture medium was highly effective for diminishing the rate of vitrification in shoots formed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.11
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• pp.2419-2422
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• 2010

The current marine internal communication systems are usually composed of NMEA0183, NMEA2000, and MiTS protocols which are located on the physical layer based on RS-422, RS-485, CAN, and EtherNet. However, general vessel communication method have a weak point that must establish the extra private line. But, the power line communication has advantage over general vessel communication method as it uses AC220V/DC24V without changing line. Therefore, we will propose a new bridge based on the DC-PLC(power Line communication) technique which support the NMEA0183 protocol inside vessel network systems.

• Journal of the Korean Chemical Society
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• v.60 no.3
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• pp.194-202
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• 2016

Two conjugated semiconducting copolymers consisting of 4,7-bis(4-(2-ethylhexyl)-2-thiophene)-2,1,3-benzothiadiazole (DTBT) and benzo[1,2-b:4,5-b']dithiophene with 5-(2-ethylhexyl)-2,2'-bithiophene (BDTBT) or 5-(2-ethylhexylthio)- 2,2'-bithiophene (BDTBT-S) were designed and synthesized as donor materials for organic photovoltaic cells (OPVs). Alkylthio-substituted PBDTBT-S-DTBT showed a higher hole mobility and lower highest occupied molecular orbital (HOMO) energy level (by 0.08 eV) than the corresponding alkyl-substituted PBDTBT-DTBT. An OPV fabricated using PBDTBT-S-DTBT showed higher V_OC and J_SC values of 0.83 V and 7.56 mA/cm², respectively, than those of a device fabricated using PBDTBT-DTBT (0.74 V) leading to a power conversion efficiency of 2.05% under AM 1.5G 100 mW/cm² illumination.

• Nuclear Engineering and Technology
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• v.55 no.10
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• pp.3591-3598
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• 2023

Photoneutron background spectroscopy observations at linac are essential for directing accelerator shielding and subtracting background signals. Therefore, we constructed a Bonner Sphere Spectrometer (BSS) system based on an array of BF₃ gas proportional counter tubes. Initially, the response of the BSS system was simulated using the MCNP5 code. Next, the response of the system was calibrated by using neutrons with energies of 2.86 MeV and 14.84 MeV. Then, the system was employed to measure the spectrum of the ²⁴¹Am-Be neutron source, and the results were unfolded by using the Gravel and EM algorithms. Using the validated system, the undesirable neutron spectrum of the 120 MeV electron linac was finally measured and acquired. In addition, it is demonstrated that the equivalent undesirable neutron dose at a distance of 3.2 m from the linac is 19.7 mSv/h. The results measured by the above methods could provide guidance for linac-related research.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.28 no.5
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• pp.217-221
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• 2018

Selective laser melting (SLM) technique is one of the additive manufacturing processes, in which functional, complex parts can be directly manufactured by selective melting layers of powder. SLM technique has received great attention due to offering a facile part-manufacturing route and utilizing a hard-to-manufacturing material (e.g. Ti6Al4V). The SLM process allows the accurate fabrication of near-net shaped parts and the significant reduction in the consumption of raw materials when compared to the traditional manufacturing processes such as casting and/or forging. In this study, we focus the high-speed additive manufacturing of Ti6Al4V parts in the aspect of manufacturing time, controlling various process parameters.

• Proceedings of the Korean Society of Computer Information Conference
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• 2013.01a
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• pp.287-290
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• 2013

본 논문에서는 DICOM 영상을 UPnP Server로 구현된 PACS 서버를 설계하고 UPnP Renderer를 이용하여 스트리밍 전송으로 화면에 출력하고 전송하여 병원에서의 진단 진료 시스템의 효율을 높일 수 있고 사용자 서비스적 관점의 이동형 의료정보시스템을 제안하고자 한다. 본 논문에서의 DICOM 엔진은 PACS 에서의 영상 취득 서버의 과부화 문제를 해결하고 의료 정보통합의 과정에서 다양한 프로세싱 방법으로 사용될 것이며, 홈 네트워크나 PnP 기능으로 제한되어 있던 UPnP 미들웨어의 다양한 서비스 활용이 가능할 것으로 사료된다.