• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.605-606
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• 2008

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.7
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• pp.625-634
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• 2016

A full digital receiving active phased array antenna generates final receiving beams by digital beam forming of received digital signals in element-level that makes difficult to use typical near-field measurement method. Thus in this paper, a modified near-field measurement method which is suitable for full digital receiving active phased array antenna is proposed. Also the measured results of receiving beam pattern and G/T using developed L-band full digital receiving active phased array antenna are shown for the verification of proposed method.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.5
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• pp.949-958
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• 2018

A voice recognition control system is a system for controlling a peripheral device by recognizing a voice. Recently, a voice recognition control system have been applied not only to smart devices but also to various environments ranging from IoT(: Internet of Things), robots, and vehicles. In such a voice recognition control system, the recognition rate is lowered due to the ambient noise in addition to the voice of the user. In this paper, we propose a dual channel acoustic beamforming hardware architecture for MEMS(: Microelectromechanical Systems) microphones to eliminate ambient noise in addition to user's voice. And the proposed hardware architecture is designed as ASIC(: Application-Specific Integrated Circuit) using TowerJazz $0.18{\mu}m$ CMOS(: Complementary Metal-Oxide Semiconductor) technology. The designed dual channel acoustic beamforming ASIC has a die size of $48mm^2$, and the directivity index of the user's voice were measured to be 4.233㏈.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.222-225
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• 2000

BSCCO thin films have been fabricated by co-deposition at an ultralow growth rate using ion beam sputtering(IBS) method. Bi 2212 phase appeared in the temperature range of 750 and $795^{\circ}C$ and single phase of Bi 2201 existed in the lower region than $785^{\circ}C$. Whereas, $Po_3$ dependance on structural formation was scarcely observed regardless of the pressure variation. And high quality of c-axis oriented Bi 2212 thin film with $T_c$ (onset) of about 90 K and $T_c$(zero) of about 45 K is obtained. Only a smd amount of CuO in some films was observed as impurity, and no impurity phase such as $CaCuO_2$ was observed in d of the obtained films.

• Korean Journal of Optics and Photonics
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• v.12 no.1
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• pp.48-54
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• 2001

We investigate the generation of the dark spatial soliton and its role of wave guiding in Fe doped$LiNbO_3$ A cw Ar+ laser of 488 nm is used for the generation of the dark spatial soliton. The generation of the dark spatial soliton is observed even at the laser intensity as low as 10 mW/cm2. The self-defocusing effect is observed when the direction of the intensity variation is parallel to the optic axis, while it can't be seen when perpendicular to the axis. So, it is verified that the refractive index change is generated parallel to the optic axis. When 633 nm He-Ne laser beam is injected into the dark spatial soliton, the beam propagates just as in the diffraction free medium. So, it is verified that the dark spatial soliton can act as a waveguide.eguide.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1468-1469
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• 2007

포항가속기 연구소에서는 RIS 프로젝트 사업과제의 일환인 L-band 산업용 전자빔 가속기의 제작 및 기술개발 연구를 철원의 물리기술연고소 주관으로 수행하고 있다. L-band 산업용 전자빔 가속기는 전자빔에 의한 고분자개질 공정, 농수산물의 멸균 및 의료기기의 멸균 등에 적용이 가능하다. 포항가속기연구소에서는 10 MeV급 산업용 전자빔 조사장치에 적용되는 RF증폭기용 펄스 전원장치인 모듈레이터를 설계, 제작을 하였다. 펄스 전원장치인 이 모듈레이터 시스템은 평균 출력 60 kW, 펄스폭 7 us, 펄스반복율 300 Hz의 L-band 상업용 RF 증폭기 전원장치이며, RF 증폭기로 사용되는 클라이스트론은 Thales 사의 TV2022D를 사용하였다. 본 논문에서는 펄스 전원장치인 모듈레이터의 운전과 인터록을 위한 제어장치의 개발과 제작에 대하여 논하고자 한다.

• Journal of the Korean Vacuum Society
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• v.20 no.1
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• pp.1-6
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• 2011

A sudden step change is observed in the vertical position readings from beam position monitors (BPMs) mounted at the several sector vacuum chambers of Pohang Light Source. To study the source of this sudden step change, we measured the RF transmission scattering matrix (S21) through the pickup electrodes of BPMs mounted at the both ends of the sector vacuum chamber. The measured $S_{21}$ graph of the sector vacuum chambers suffering sudden step change has a peak in the BPM operation frequency bandwidth. Otherwise that of the other sector vacuum chambers doesn't have a peak. It is shown by the numerical simulation that the peak found in the BPM operation frequency bandwidth corresponds to the longitudinal harmonic of transverse electric resonance mode.

• Spatial Information Research
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• v.7 no.1
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• pp.63-79
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• 1999

In this research, the operational principle and the internal algorithm of theodolite measuring systems are studied and coded for a new software, and the feasibility of the laser system for the above mentioned usage is studied by simulation set-up of the system in the laboratory environment, and for the theodolite system modules for the communication between theodolite and computer is implemented, the data collection and storage, the simultaneous photogrammetric ' bundle ' adjustment for the theodolite position and the target points are coded, compiled and tested. for the simulation set-up of the laser system extensive studies on laser sources and laser detectors are performed, the system composition for the system simulation in the laboratory environment is studied and implemented, and the beam fluctuation due to the environmental changes in the course of the laser beam, such as changes in current of wind or in temperature is experimented. According to Experiment on the Source of 17 meters interval and the Detector, Laser beam is almost doesn't depend on air How, but it is effected by variations of temperature and light. Selecting cloudy day and time without change of temperature, it was realized that it is possible to perform deformation measurement more than approximately 2mm precision.precision.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.517-518
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• 2007

• Korean Journal of Optics and Photonics
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• v.8 no.3
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• pp.183-188
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• 1997

Cut-off filters would reject all the radiation below and transmit all that above a certain wavelength or vice versa. In this paper, we study design and farbrication of dichroic mirror and broadband high reflective mirror for color separation of white laser beam source to R.G.B color beam source. In laser display system, color separation is very important. We fabricated below specific component for finite color separation of the Kr-Ar laser source. At 45$^{\circ}$ incidence s-polarized light , it is required that - H/R in blue region R>99%, H/T in green and red region T>90% - H/R in green and red region R>99%, H/T in blue region T>90% - H/R in green region R>99%, H/T in red region T>90% We composed the optical system and realize the full color image.