• Title/Summary/Keyword: limit current

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Influence of Prescribed Gamitaeeumjowi-tang on Liver Function : Prospective Single-center Pilot Study (가미 태음조위탕 복용이 간기능에 미치는 영향 : 전향적 단일기관 예비연구)

  • Jin, Yong-Huei;Kim, Kang-Sik;Han, In-Yeop;Lee, Hyun-Bae
    • Journal of Korean Medicine for Obesity Research
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    • v.10 no.1
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    • pp.29-40
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    • 2010
  • Objective The aim of this study was to evaluate the influence of Gamitaeeumjowi-tang(GTT) prescribed by doctors of korean(KMD) medicine on liver function. Methods For this single-center, prospective, observational study, we enrolled patients who wished to take GTT prescribed by KMD for losing weight. sixty(60) patients took GTT for 33.8 days and completed questionnaires. Liver function tests(LFTs) were performed bofore(first test) and after each GTT treatment(finish test). For LFT, T-bil, ALP, AST, ALT were measured. Result There were no significant changes in LFT data between the first and finish tests. At first test, levels of test seven(7) patients were more than twice of normal range of upper limit, levels of eight(8) patients were more than normal range of upper limit, less than twice of normal range of upper limit. At last test, levels of nine(9) patients were more than normal range of upper limit, less than twice of normal range of upper limit. Conclusion The current study showed that ingestion of GTT prescribed by KMD did not increase the frequency of abnormal LFTs, at least in the short term.

Evaluation of Analytical Parameters on Forming Limit Diagram based on Initial Geometrical Instability (초기 형상 불안정성 기반 성형한계선도의 이론적 변수에 따른 성형 한계영역 평가)

  • Noh, H.G.;Lee, B.E.;Kim, J.;Kang, B.S.;Song, W.J.
    • Transactions of Materials Processing
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    • v.23 no.4
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    • pp.199-205
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    • 2014
  • The current study examines the effect of the analytical parameter values on the theoretical forming limit diagram (FLD) based on the Marciniak-Kuczynski model (M-K model). Tensile tests were performed to obtain stress-strain curves and determine the anisotropic properties in the rolling, transverse and diagonal direction of SPCC sheet materials. The experimental forming limit curve for SPCC sheet material was obtained by limiting dome stretching tests. To predict the theoretical FLD based on the M-K model, the Hosford 79 yield function was employed. The effects of three analytical parameters - the exponent of the yield function, the initial imperfection parameter and the fracture criterion parameter - on the M-K model, were examined and the results of the theoretical FLD were compared to the experimentally measured FLD. It was found that the various analytical parameters should be carefully considered to reasonably predict the theoretical FLD. The comparison of the acceptable forming limit area between the theoretical and experimental FLD is used to compare the two diagrams.

A study on Korean drivers' acceptance and traffic sign conditions assessment for Speed Assistance Systems (속도제한 지원장치에 대한 운전자 인식도 및 도로환경 분석)

  • Lee, Hwa Soo;Cho, Jae Ho;Yim, Jong Hyun;Lee, Hong Guk;Chang, Kyung Jin;Yoo, Song Min
    • Journal of Auto-vehicle Safety Association
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    • v.7 no.3
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    • pp.30-34
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    • 2015
  • This study examined the Korean drivers' acceptance of SAS(Speed Assistance systems) and traffic sign conditions in Korea roads for SLIF(Speed Limit Information Function) that is a part of SAS. Exceeding the speed limit is a factor in the severity of many road accidents and SAS would help the driver to observe a speed limit by warning and/or effectively limiting the speed of the vehicle. SAS are in the initial phase in Korea, Korean drivers could not be familiar with automatical speed limiting during driving, SAS interface design would be considered to be more readily acceptable to the public. And advanced SAS have been introduced onto the market which are able to inform the driver of the current speed limit based on camera and/or digital maps based SLIF. These systems are based on external data using sensors, so environmental conditions are an important factor which could cause malfunction of SLIF functions.

Tests of Inductive High-Tc Superconducting Fault Current Limiter with an Air-Gap (공극형 고온초전도한류기의 특성실험)

  • Joo, Min-Seok;Lee, Chan-Ju;Chu, Yong;Ko, Tae-Kuk
    • Proceedings of the KIEE Conference
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    • 1996.07a
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    • pp.181-183
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    • 1996
  • A novel model of an inductive superconducting fault current limiter with an inductive superconducting fault current limiter with the air-gap core was fabricated and tested. If its impedance is not high enough to limit the fault current, then destructive damage occurs in the power system. We attained a magnetic saturation under higher current by an effective air gap introduced in the core. The fault current was successfully limited to two times as much as the nominal current at a 60 Hz source having an effective voltage of 70 V. The fault current flowing under such conditions can be limited to a desired value without any fault current peak within 1/4 cycles.

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Current Limiting Characteristics of Superconducting Fault Current Limiter for Reduction of Unsymmetrical Fault Current in a Three-Phase Power System (삼상전력계통의 비대칭고장전류 저감을 위한 초전도한류기의 전류제한특성)

  • Kim, Min-Yeong;Lim, Sung-Hun;Hwang, Jong-Sun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2010.03b
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    • pp.8-8
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    • 2010
  • In this paper, the limiting characteristics of the fault current in a power system with a superconducting fault current limiter(SFCL) applied into neutral line of main transformer in a distribution power line were analyzed. The SFCL applied into the neutral line of main transformer power system can limit the unsymmetrical fault current from the single-line ground fault or the double-line ground fault. In addition, it could be decreased a number of SFCL and a load. This method could be expected to reduction of a power loss in the neutral line, because of a neutral line current is zero in ordinary times.

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A New Current Controlled PWM technique for NPC Inverter (NPC 인버터를 위한 새로운 전류제어 기법)

  • 이병송;김길동;변윤섭;한영재;박현주
    • Proceedings of the KIPE Conference
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    • 1998.07a
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    • pp.63-69
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    • 1998
  • A new current controlled PWM technique with NPC structure is proposed in this paper. A current controlled PWM technique with neutral-point-clamped pulse-width modulation inverter composed of main switching devices which operates as switch for PWM and auxiliary switching devices to clamp the output terminal potential to the neutral point potential is described. The proposed current controller has a first and second current band. The switching pattern will be made by the first current band. According to the second current band, the output state of the switching pattern is changed into positive and negative state. This inverter output contains less harmonic content and lower switching frequency than that of conventional current controlled PWM technique at the same current limit. Two inverters are compared analytically and the performance is investigated by the computer simulation.

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Analysis on Reduction Method of Symmetrical Fault Current in a Power System with a SFCL applied into Neutral Line (전력계통의 중성선에 적용된 초전도한류기의 대칭고장전류 저감방안 분석)

  • Lim, Sung-Hun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.23 no.2
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    • pp.148-152
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    • 2010
  • The superconducting fault current limiter (SFCL) applied into the neural line of a power system, which can limit the unsymmetrical fault current from the single-line ground fault or the double-line ground fault, was reported to be the effective application location of the SFCL in a power system. However, the limiting operation for the symmetrical fault current like the triple line-ground fault is not effective because of properties of the balanced three-phase system. In this paper, the limiting method of the symmetrical fault current in a power system with a SFCL applied into neutral line was suggested. Through the short-circuit experiments of the three-phase fault types for the suggested method, the fault current limiting and recovery characteristics of the SFCL in the neutral line were analyzed and the effectiveness of the suggested method was described.

Study on Current Limiting Characteristics of a Flux-locktype SFCL using Series Connected Two Coils with Twice Triggering Operation

  • Han, Tae-Hee;Ko, Seok-Cheol;Lee, Byongjun;Lim, Sung-Hun
    • Journal of Electrical Engineering and Technology
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    • v.9 no.3
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    • pp.777-781
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    • 2014
  • The current limiting characteristics of the flux-lock type superconducting fault current limiter (SFCL) using series connected two coils with twice triggering operation, which consists of series connected two coils and two superconducting (SC) modules with the inserting resistance, was analyzed. The feature of the suggested SFCL is that it can limit the fault current by triggering either one SC module or two SC modules comprising the SFCL depending on the amplitude of the fault current. To verify the current limiting operation of the suggested SFCL, the short-circuits in the fault location with the different fault currents were tested and its useful operations were described through the analysis on the tested results.

Estimation of liquid limit of cohesive soil using video-based vibration measurement

  • Matthew Sands;Evan Hayes;Soonkie Nam;Jinki Kim
    • Geomechanics and Engineering
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    • v.33 no.2
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    • pp.175-182
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    • 2023
  • In general, the design of structures and its construction processes are fundamentally dependent on their foundation and supporting ground. Thus, it is imperative to understand the behavior of the soil under certain stress and drainage conditions. As it is well known that certain characteristics and behaviors of soils with fines are highly dependent on water content, it is critical to accurately measure and identify the status of the soils in terms of water contents. Liquid limit is one of the important soil index properties to define such characteristics. However, liquid limit measurement can be affected by the proficiency of the operator. On the other hand, dynamic properties of soils are also necessary in many different applications and current testing methods often require special equipment in the laboratory, which is often expensive and sensitive to test conditions. In order to address these concerns and advance the state of the art, this study explores a novel method to determine the liquid limit of cohesive soil by employing video-based vibration analysis. In this research, the modal characteristics of cohesive soil columns are extracted from videos by utilizing phase-based motion estimation. By utilizing the proposed method that analyzes the optical flow in every pixel of the series of frames that effectively represents the motion of corresponding points of the soil specimen, the vibration characteristics of the entire soil specimen could be assessed in a non-contact and non-destructive manner. The experimental investigation results compared with the liquid limit determined by the standard method verify that the proposed method reliably and straightforwardly identifies the liquid limit of clay. It is envisioned that the proposed approach could be applied to measuring liquid limit of soil in practical field, entertaining its simple implementation that only requires a digital camera or even a smartphone without the need for special equipment that may be subject to the proficiency of the operator.

Current Limiting Characteristics of a Resistive SFCL for a Single-line-to-ground Fault in the 22.9 kV System (1선 지락사고에 대한 배전급 저항형 초전도 한류기의 전류제한특성)

  • 최효상;황시돌;현옥배
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.14 no.6
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    • pp.505-510
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    • 2001
  • We simulated the current limiting characteristics of a resistive superconducting fault current limiter (SFCL) for a single line-to-ground fault in the 22.9 kV system. The transient current during the fault increased to 6.33 kA, 5.80 kA and 3.71 kA without SFCL at the fault angles 0$^{\circ}$, 45$^{\circ}$ and 90$^{\circ}$, respectively, a resistive SFCL limited effectively the fault current to 2.27 kA in a half cycle without any DC components. The maximum quench resistance of an SFCL, 16Ω was suggested to be appropriate to limit the fault current in the 22.9 kV distribution system, considering the operating cooperation of a protective relay and the current limiting performance of an SFCL.

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