• Title/Summary/Keyword: phase meter

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Surface Deformation and Behavior of Magma Activity Using EDM (EDM을 활용한 지표변화율과 마그마 활동 양상 변화 연구)

  • Yun, Sung-Hyo;Lee, Jeong-Hyun
    • The Journal of the Petrological Society of Korea
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    • v.22 no.1
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    • pp.71-81
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    • 2013
  • Measuring the distance between benchmarks placed on a volcano tens to thousands of meters apart can sometimes pinpoint where and when magma is rising toward the surface. Rising magma will sometimes push overlying rocks upward or shove them aside. In either case, one part of the volcano may actually move horizontally relative to another part from as little as a few millimeters to as much as several tens of meters. The challenge in measuring such changes with an electronic distance meter is putting benchmarks in the right places and making frequent measurements between pairs of benchmarks. An electronic distance meter is an instrument that both sends and receives an electromagnetic signal. Depending on the distance between the EDM and reflector, the wavelength of the returned signal will be out of phase with the transmitted signal. The instrument compares the phase of the transmitted and received signals and measures the phase difference electronically. There is a wide range of EDM capabilities in range and precision, but for volcano monitoring purposes, short-range (less than 10 km) to medium-range (less than 50 km) EDM's are typically used. Short-range EDM's transmit and receive the near visible infrared part of the electromagnetic spectrum for measuring distances with an accuracy of about 5 mm.

The immediate effects of spiral taping on improvement of gait ability in patients with chronic stroke (나선형 테이핑 적용이 만성 뇌졸중 환자의 보행능력 개선에 미치는 즉각적인 효과)

  • Kim, Dong-Dae;Park, Shin-Jun
    • Journal of Digital Convergence
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    • v.15 no.4
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    • pp.529-536
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    • 2017
  • The purpose of this study is to examine the immediate effects of spiral taping applied to an affected leg on gait ability in stroke patients. Forty two stroke patients were divided into a spiral taping group (n=21) and a quadriceps femoris group (n=21), and each taping method was applied. Spatiotemporal Gait Parameters (Cadence, speed, gait cycle duration, stance phase duration, double support duration) were measured using the 10-meter walk test, the dynamic gait index (DGI) and an accelerometer for both groups. Both groups showed a significant increase in a 10-minute walk, the DGI, cadence, speed before and after the intervention, whereas no significant difference was detected in stance phase duration, gait cycle duration and double support duration on the affected side in all groups. All groups revealed no significant difference in variation. It has been found that the two taping methods augment gait ability in patients with stroke. This study suggests that spiral taping can be an easily applicable method at home.

Numerical investigation of the large over-reading of Venturi flow rate in ARE of nuclear power plant

  • Wang, Hong;Zhu, Zhimao;Zhang, Miao;Han, Jinlong
    • Nuclear Engineering and Technology
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    • v.53 no.1
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    • pp.69-78
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    • 2021
  • Venturi meter is frequently used in feed water flow control system in a nuclear power plant. Its accurate measurement plays a vital role in the safe operation of the plant. This paper firstly investigates the influence of the length of each section of pipeline, the throat inner diameter of Venturi and the flow characteristics in a single-phase flow on the accuracy of Venturi measurement by numerical calculation. Then the flow and the accuracy are discussed in a multi-phase flow. Numerical results show that the geometrical parameters and the characteristics of complex turbulent flow in the single-phase flow have little impact on the accuracy of Venturi flow rate measurement. In the multi-phase flow, the calculated flow rate of Venturi deviated from the actual flow rate and this deviation value is closely related to the amount of steam in the pipeline and increases sharply with the increase of the amount of steam. The over-reading of Venturi flow rate is present.

Mother Wavelet Transform Suitable to Fault Method Algorism (고장 표정 알고리즘에 적합한 원형 웨이브릿 변환)

  • Park, In-Deok;Lee, Seung-Hwan;Kim, Si-Kyung
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.62_63
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    • 2009
  • This paper is distribution utility to generation of analysis fault several cases on the ground of substation in a energy meter three phase current, voltage data measurement to fault type and characteristics. Mother wavelet transformation of suitable to method algorism from the distribution utility to generation of fault in image impedance etc several parameter for utility characteristics effective to probatory.

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Characteristic Analysis of Motor using VIS (VIS를 이용한 전기기기 특성 해석)

  • Lee, I.Y.;Kim, Y.W.;Kim, Y.M.
    • Proceedings of the KIEE Conference
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    • 2004.07e
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    • pp.126-129
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    • 2004
  • This paper presents the way to analyze the static and dynamic characteristics of the Compound motor and 3 phase slip ring motor using VIS (Virtual Instrument System) and Agilent VEE, GUI(Graphics User Interface) tool. This method is composed of real time measuring of various characteristics, which can't measure using analog meter and analyzer, and presenting and analyzing the static and dynamic characteristics by table, which calculates the measured parameter. Also, this can apply to the various parts.

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Mother Wavelet Transform using Distribution Utility of Fault Point Extraction (원형 웨이브릿 변환을 이용한 배전계통의 고장점 추출)

  • Park, In-Deok;Lee, Seung-Hwan;Choi, Kwang-Jin;Kim, Si-Kyung
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.10
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    • pp.1855-1860
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    • 2009
  • This paper caused a distribution utility to generation of analysis fault several cases on the ground of substation in a energy meter three phase current, voltage data measurement to fault type and characteristics. Mother wavelet transformation of suitable to method algorithm from the distribution utility to generation of fault in image impedance etc several parameter for utility characteristics effective to probatory fault point extraction.

Speed Control of Three Phase Slotless PM BLDC Motor Using Single Sensor (Single Sensor를 이용한 3상 Slotless PM BLDC 전동기의 속도제어)

  • Lee S. J.;Yoon Y. H.;Woo M. S.;Won C. Y.;Choe Y. Y.
    • Proceedings of the KIPE Conference
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    • 2004.07a
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    • pp.33-37
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    • 2004
  • Slotless Permanent magnet Brushless DC Motor(PM BLDC) with the characteristics of high speed and high power density has been more widely used in industrial and automatic machine. Generally, PM BLDC meter is necessary that the three Hall-ICs evenly be distributed around the stator circumference in case of the 3 phase motor. The Hall-ICs are set up in this motor to detect the main flux from the rotor. therefore the output signal from Hall-ICs is used to drive a power transistor to control the stator winding current. However, instead of using three Hall-ICs, if only we used one Hall-IC, we estimate information of the others phase in sequence through a revolving rotor. This paper identified the characteristics and performance by using one Hall-IC for the 3 phase PM BLDC whose six stator and two rotor designed.

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Dielectric Characteristics in Smectic Phase

  • Song, Jun-Ho;Coi, Suck;Kim, Yong-Bae;Kumar, Satyendra;Souk, Jun-Hyung;Shin, Sung-Tae
    • 한국정보디스플레이학회:학술대회논문집
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    • 2002.08a
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    • pp.419-422
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    • 2002
  • We have studied dielectric properties in the smectic phases of 4-(6-ethoxy-1-trifluoromethyl-hexyloxycarbonyl)-phenyl-4-Nonyloxybiphenyl-4-carboxylat ( TFMEOHPNBC ) having fluorine attached to one of its benzene rings. Homogeneous and homeotropic 1.5 and 5${\mu}m$ thick test cells were prepared to analyze molecular dynamic property. We measured capacitance as a function of temperature in the frequency range between 20 Hz and 100 kHz by using HP4284A LCR meter. We observed that the homogeneous cell has high dielectric constant causing dipole moment in smectic $C^{\ast}$ phase, but we can see the dipole moments are canceled out in antiferroelectric phase. It is found that there are two kind of the relaxation director fluctuation below 100 kHz. The first is ionic or space charge contribution below 10 Hz, and the second is Goldstone mode near 1-2 kHz. We will discuss molecular dynamics in smectic phase from extra information such as x-ray and electrooptic data.

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Effect of Obstacle Walking Training Combined with Cognitive Tasks on Balance, Gait, and Activities of Daily Living in Patients with Stroke: A Single Case Study (인지과제를 결합한 장애물 보행훈련이 뇌졸중 환자의 균형과 보행능력 및 일상생활동작에 미치는 효과 -단일사례연구-)

  • Min-Jeong Song;Beom-Ryong Kim
    • PNF and Movement
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    • v.21 no.1
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    • pp.11-18
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    • 2023
  • Purpose: This study aims to compare the effects of obstacle walking training combined with cognitive tasks on balance, gait, and activities of daily living in patients with stroke. Methods: A single-subject design was used, where one stroke patient participated. Obstacle walking training combined with cognitive tasks was performed for 1 hour per day for a total of 10 times during the intervention phase. The subjects were measured five times in the baseline phase, 10 times in the intervention phase, and five times in the follow-up phase. The outcome measurements included the Berg balance scale (BBS), the 10-meter walk test (10 MWT), and the Korean modified Barthel index (K-MBI). Results: In this study, the results showed that the 10 MWT scores during the intervention period improved and that this improvement remained, even during the post-period. In addition, BBS and K-MBI values for stroke patients increased significantly after training. Conclusion: The results of this study revealed that obstacle walking training combined with cognitive task training may be helpful to improve balance, gait, and activities of daily living in stroke patients. Therefore, obstacle walking training combined with cognitive tasks is recommended for stroke patients.

Behaviors of Ionic Conductivity with Temperature for High-Temperature PEMFC Containing Room Temperature ionic Liquids Under Non-humidified Condition (상온 이온액을 이용한 고온 무수 PEMFC용 고정화 액막의 온도에 따른 이온전도도 거동)

  • Kim, Beom-Sik;Byun, Yong-Hoon;Park, You-In;Lee, Sang-Hak;Lee, Jung-Min;Koo, Kee-Kahb
    • Membrane Journal
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    • v.16 no.4
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    • pp.268-275
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    • 2006
  • Novel SILEMs were prepared by multi-stage phase separation process combined by the low temperature phase separation (LTPS) and the high temperature phase separation (HTPS) using room temperature ionic liquids (RTILs) which have a high ionic conductivity. PVDF and imidazolium series ionic liquids were used as membrane material and electrolyte, respectively. To study the ion conducting properties, the SILEMs were tested using LCR meter at temperature controlled from 30 to $130^{\circ}C$. Under humid conditions, with increasing temperature from 30 to $100^{\circ}C$, the ion conductivity of the cast $Nafion^{(R)}$ membrane increased linearly, but then started to decrease after $100^{\circ}C$. However, in the case of the SILEMs, with increasing operating temperature, the ion conductivity increased. Also, the ion conductivity behaviors of the SILEMs were almost same, regardless of humidity. The ion conductivity of the SILEMs was $2.7{\times}10^{-3}S/cm$ and increased almost linearly up to $2.2{\times}10^{-2}S/cm$ with increasing temperature to $130^{\circ}C$. The effects of an inorganic filler on the physical properties of the SILEMs were studied using the $SiO_2$. The addition of $SiO_2$ could improve the mechanical strength of the SILEMs, though the ionic conductivity was decreased slightly.