• Title/Summary/Keyword: phase meter

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A Ferrite filled Electromagnetic Delay Line using Short-Circuited Coils (단락 코일을 사용한 페아라이트 전자 지연선)

  • 이병화;정선호
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.3 no.1
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    • pp.12-17
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    • 1966
  • A more extensive theoretical analysis for a ferrite filled electromagnetic delay line of two coaxial anisotropic conducting cylinders was made and improvements of the delay line n=0 mode operation was achieved by separating effective sections using short-circuited coils to eliminate unnecessary couplings among windings of different phase. Time delay of order of 10 microseconds per meter in video frequency range was observed from 3"/8 diameter 6" long delay line tilled with ferrite material. Design formula was presented with illustrative discussions to help design for practical purposes. purposes.

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Estimating Black Hole Mass in Active Galactic Nuclei with Hydrogen Brackett lines

  • Kim, Do-Hyeong;Im, Myeong-Sin
    • The Bulletin of The Korean Astronomical Society
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    • v.35 no.2
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    • pp.32.2-32.2
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    • 2010
  • Red dusty Active Galactic Nuclei (AGNs) are suspected to mid-stage between ULIRG and AGN phase. As well as, they are suspected that they have more than 50% of AGN population. To understand character of red AGN, Black Hole (BH) mass of red AGN is a key property and haven't measured by existing method such as reverberation mapping and single epoch method. So we still don't know their character and properties clearly. To estimate properties of red AGNs escape from effect of dust-obscuration, we have obtained Near InfraRed (NIR) spectra of 31 reverberation mapped AGNs and 49 Palomar-Green(PG) Quasi-Stellar Object (QSO) using the infrared camera (IRC) for AKARI with unique wavelength range 2.5-$5.0{\mu}m$. From this spectra, we measured the FWHM and luminosity of brackett ${\alpha}$, ${\beta}$ at 4.0, 2.6 micron meter for deriving new BH mass estimators based on the properties of Brackett line emission.

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Absolute Evaluation of Capacitor and Inductor Using Voltage Transformer Comparator (전압변성기 비교기를 이용한 커패시터와 인덕터의 절대 평가)

  • Han, Sang-Gil;Kim, Yoon-Hyoung;Jung, Jae-Kap;Kim, Han-Jun;Han, Sang-Ok
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.57 no.3
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    • pp.285-290
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    • 2008
  • We have developed the absolute evaluation technique of capacitor and inductor by measuring the phase displacement as a function of resistance of employed resistors in voltage transformer(VT) comparator. The methods were applied to the capacitor with the range of 100 nF - $5{\mu}F$ and the inductor with the range of $100{\mu}H{\sim}1\;H$. The capacitance values of capacitor obtained using our method are consistent within the expanded uncertainty those obtained using capacitor bridge. The inductance values of inductor obtained using our method are also consistent within the expanded uncertainty those obtained using LCR meter.

A Simple a.c. Magnetic Susceptometer Using self-inductance Measurement of a Single Coil Mounted on a Cryostat Cold Head

  • Dho, Joong-Hoe
    • Journal of Magnetics
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    • v.13 no.4
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    • pp.177-181
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    • 2008
  • A very simple a.c. magnetic susceptometer for use in a helium closed cycle cryostat is reported in this paper. This simple setup has only a single bobbin-less copper coil, instead of the primary coil and two secondary coils typically used in mutual-inductance types. The single bobbin-less copper coil is directly mounted on the cryostat cold head. A sample is attached on the inside wall of the copper coil using a thermal contact material and its a.c. magnetic susceptibility is obtained from the measurement of the self-inductance of the sample coil using an LCR meter or an impedance analyzer. Experimental details are described and illustrative measurements on magnetic and superconducting materials as a function of temperature are included. The performances and limitations of this simple a.c. magnetic suceptometer are also discussed.

The Study on the Voltage Improvement in Distribution Line(I) (배전선로(配電線路)의 전압개선(電壓改善) 대책(對策)에 관한 연구(硏究)(I))

  • Kim, Ho-Yong;Rho, Dae-Sook;Son, Soo-Kook;Kim, Sang-Jun;Son, Il-Keun
    • Proceedings of the KIEE Conference
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    • 1988.07a
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    • pp.888-891
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    • 1988
  • Recently, with the expansion of electronic equipment and computer facilities, good quality of services is required. This paper describes how to improve distribution system voltage by the Tap position seletion of P. Tr, by the decision of the optimal sending voltage in substation and we also developed three phase load flow program in distribution system. Besides we have developed the digital recording voltmeter that will be utilized with personal computer system. This meter will be useful, economical and powerful.

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Torque measurement of Disk type Single Phase Switched Reluctance Motor (디스크형 단상 스위치드 릴럭턴스 모터의 토오크 측정)

  • Kim, Jun-Ho;Lee, Eun-Woong;Oh, Young-Woong;Kim, Sung-Jong;Woo, Sung-Bong;Lee, Min-Myung;Lee, Jong-Han
    • Proceedings of the KIEE Conference
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    • 2000.07b
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    • pp.678-680
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    • 2000
  • We designed and manufactured DSPSRM using the usual output power equation of rotating machine. And the sinusoidaly approximated torque characteristics are achieved by 3D finite element analysis. Also, We calculated average torque per rotation using approximated torque data, calculated by 3D finite element analysis. On this paper, We manufacture torque-meter set and measure the torque characteristic of DSPSRM.

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Evaluation of Characteristics of Oxidized Thin LPCVD-$Si_{3}N_{4}$ Film (얇은 열산화-질화막의 특성평가)

  • 구경완;조성길;홍봉식
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.29A no.9
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    • pp.29-35
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    • 1992
  • Dielectric thin film of N/O (Si$_{3}N_[4}/SIO_{2}$) for high density stacked dynamic-RAM cell was formed by LPCVD and oxidation(Dry & pyrogenic oxidation methods) of the top Si$_{3}N_[4}$ film. The thickness, structure and composition of this film were measured by ellipsometer, high frequency C-V meter, high resolution TEM, AES, and SIMS. The thickness limit of Si$_{3}N_[4}$ film in making thin N/O structure layer was 7nm. In this experiment, the film with thinner than 7nm was not thick enough as oxygen diffusion barrier, and oxygen punched through the film and interfacial oxidation occurred at the phase boundary between Si$_{3}N_[4}$ and polycrystalline silicon electrode.

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Establishing the Black Hole Mass Estimator of Active Galactic Nuclei with Hydrogen Brackett Lines

  • Kim, Do-Hyeong;Im, Myeong-Sin
    • The Bulletin of The Korean Astronomical Society
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    • v.36 no.1
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    • pp.51.1-51.1
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    • 2011
  • Red dusty Active Galactic Nuclei (AGNs) are suspected to mid-stage between ULIRG and AGN phase. As well as, red AGNs are suspected that they have more than 50% of whole AGN population. In order to understand the character of red AGNs, Black Hole (BH) mass of red AGN is a key property and can not measured by existing method such as reverberation mapping and single epoch method. Thus we still don't know their character and properties in clearly. To estimate properties of red AGNs without the effect of dust-obscuration, we have obtained Near InfraRed (NIR) spectra of 31 reverberation mapped AGNs and 49 Palomar-Green(PG) Quasi-Stellar Object (QSO) by using the infrared camera (IRC) for AKARI with unique wavelength range $2.5-5.0{\mu}m$. From this spectra, we measured the FWHM and luminosity of brackett ${\alpha}$ and ${\beta}$ at 4.0, 2.6 micron meter for deriving new BH mass estimators based on the properties of Brackett line emission.

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A Highly Efficient and Fast Algorithm for Implementing a Real-Time Software GNSS Receiver

  • Im, Sung-Hyuck;Jee, Gyu-In;Kim, Hak-Sun;Cho, Sang-Do;Ko, Sun-Jun
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.2
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    • pp.395-398
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    • 2006
  • In this paper, for implementing a real-time software GNSS receiver we propose the highly efficient and fast algorithms such as partial down-conversion, phase rotator, composite I&Q accumulation, Virtual DCO technique, and parallel acquisition using FFT. When the proposed algorithms are used, more 30 tracking channels with 3 tracking arm(early-prompt-late) is operated real-time on Intel 2.8GHz personal computer. Also, the partial down-conversion reduces the FFT size, for parallel acquisition, to 1/8 of conventional FFT-size and the program size includes map is not exceed 1Mbyte. Finally, the proposed real-time software GNSS receiver using the proposed algorithms provides the navigation solution with below 10 meter rms error.

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Clinical Feasibility of Mental Practice for Gait Ability Improvement of Parkinson Disease Patients: ABA Single Subject Design

  • Song, Hyun Seung;Kim, Jin Young
    • The Journal of Korean Physical Therapy
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    • v.26 no.6
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    • pp.398-402
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    • 2014
  • Purpose: This study was carried out in order to verify actual applicability of mental practice in the clinical field by applying it to Parkinson disease patients. Methods: : The number of subjects was three and they were aged between 65 and 69. One year or longer period has passed since they were diagnosed with Parkinson disease. The baseline A consisted of three sessions. After the baseline period, the researcher applied mental practice to the subjects once per day, for 20 minutes per each time, for 10 sessions. The no-intervention withdrawal phase was composed of three sessions. Outcome measures 10 meter walking test(10MWT), timed up and go (TUG) test, 8-figure walk test (8FWT). Results: All results indicated that 10 MWT, TUG, F8WT was improved when compared mental practice(B) to pre base line(A). base line(A) after mental practice intervention(B) was also sustained. Conclusion: As a result of the mental practice, we can know that it helps straight gait, dynamic balance, curved gait to improve.