• 제목/요약/키워드: system resistance

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내화패널이 부착된 프리캐스트 PSC 풍도슬래브의 정적/동적하중에 관한 실험연구 (Experimental Studies on PSC Airpit-Slab with Fire Resistance Panel under Static and Dynamic Loads)

  • 김태균;배정;최헌;민인기
    • 대한토목학회논문집
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    • 제32권4A호
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    • pp.245-253
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    • 2012
  • 본 연구에서는 장대터널이나 지하차도 등에 시공되는 횡류식 환기시스템을 구성하는 내화패널이 부착된 프리캐스트 풍도슬래브의 구조성능을 평가하기 위해서 실물모형 구조실험을 수행하였다. 또한, 내화패널의 휨강도와 Pull-off test를 통하여 내화패널과 슬래브의 부착성능 등의 기초성능을 우선적으로 확인하였다. 실물모형시험은 내화패널과 프리캐스트 PSC 슬래브의 정적 휨성능과 차량의 통행 시 발생하는 표면압력 이상의 하중에 대한 동적피로부착성능을 평가하였다. 동적피로하중 시험에서 내화패널과 PSC 슬래브 사이의 탈락이나 손상은 발생하지 않았으며, 정적재하시험에서도 매우 안정적인 거동을 보였으며, 하부에 부착된 내화패널의 탈락은 발생하지 않았다. 따라서 시공 중이나 시공 후 외부하중에 의해 내화패널의 탈락은 발생하지 않을 것으로 판단된다.

MF-BIA Analyzer를 이용한 경혈의 세포 내액과 외액에 의한 저항성분 추정 방법 제시 및 반영률 평가 (The Suggestion of MF BIA Analyzer Method to Reflect the Resistance in the Extracelluar and Intracelluar Fluid at Acupoint & the Evaluation of Reflection Rate on the Tissue under Skin)

  • 김수병;이나라;김원기;이용흠
    • Korean Journal of Acupuncture
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    • 제29권4호
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    • pp.563-572
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    • 2012
  • Objectives : The aim of this study was to suggest a new method to estimate the resistance by acupoint compositions by using the multi-frequency bioelectrical impedance analysis(MF-BIA) of 5 kHz, 50 kHz and 200 kHz within 2 cm of acupoints as a local segment. Moreover, we try to confirm the relation to between measured resistance at skin surface and measured resistance by various manual acupuncture needle insertion depth. Methods : Ten male subjects participated in this study. We measured the resistance at left/right ST36 at skin surface and various manual acupuncture needle insertion depth(skin, 5 mm, 10 mm, 15 mm, 20 mm, 25 mm and 30 mm). Results : It was also observed that the all measured resistances were the highest at 5 kHz and the lowest at 200 kHz. There were significant differences at 5 kHz, 50 kHz and 200 kHz between measured resistance at skin surface and measured resistance by various manual acupuncture needle insertion depth(p<0.05). There was no significant difference in the left and right identical acupoints under the identical condition(p>0.05). Conclusions : We conclude that the measured resistance at skin surface has limitation as to reflect the information of tissue. However, the measured resistance at each frequency was changed as similar pattern by different insertion depth. Hence, we confirmed the possibility of assumption on information of tissue which was expected to locate an acupoint.

RESISTANCE ESTIMATION OF A PWM-DRIVEN SOLENOID

  • Jung, H.G.;Hwang, J.Y.;Yoon, P.J.;Kim, J.H.
    • International Journal of Automotive Technology
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    • 제8권2호
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    • pp.249-258
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    • 2007
  • This paper proposes a method that can be used for the resistance estimation of a PWM (Pulse Width Modulation)-driven solenoid. By using estimated solenoid resistance, the PWM duty ratio was compensated to be proportional to the solenoid current. The proposed method was developed for use with EHB (Electro-Hydraulic Braking) systems, which are essential features of the regenerative braking system of many electric vehicles. Because the HU (Hydraulic Unit) of most EHB systems performs not only ABS/TCS/ESP (Electronic Stability Program) functions but also service braking function, the possible duration of continuous solenoid driving is so long that the generated heat can drastically change the level of solenoid resistance. The current model of the PWM-driven solenoid is further developed in this paper; from this a new resistance equation is derived. This resistance equation is solved by using an iterative method known as the FPT (fixed point theorem). Furthermore, by taking the average of the resistance estimates, it was possible to successfully eliminate the effect of measurement noise factors. Simulation results showed that the proposed method contained a sufficient pass-band in the frequency response. Experimental results also showed that adaptive solenoid driving which incorporates resistance estimations is able to maintain a linear relationship between the PWM duty ratio and the solenoid current in spite of a wide variety of ambient temperatures and continuous driving.

발전소 직류전선로의 지락안전진단 시스템에 관한 연구 (A Study on the Ground Fault Diagnosis System of Power Station DC Power line)

  • 안영주;김남호;이형기
    • 한국안전학회지
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    • 제12권1호
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    • pp.37-43
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    • 1997
  • There are two kinds of ground fault diagonosis system(GFD), which are for AC and DC power line. The ground fault current of a DC power line Is, first, analyzed for a description of a GFD system for DC power line and then the construction method of the GFD system, which could be processed and analyzed a ground fault current, are explained. Main functions of the system are that the detected ground fault current could be converted to the line insulation resistance by a program and saved in the system memory continuously. Finally a DC power line insulation safety could be decide by a change of the saved Insulation resistance for a given time. This system can detect the ground fault resistance to 100㏀.

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주행특성을 고려한 차량 견인시스템 모델링 (Modeling for Traction system of the Vehicle including Running Characteristics)

  • 변윤섭;김영철
    • 전기학회논문지
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    • 제56권11호
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    • pp.1955-1961
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    • 2007
  • In this paper, we propose the mathematical model for the vehicle system including running characteristics. The well defined model for a system is necessary to study and to enhance system performance. To model the dynamic properties of vehicle system, we have considered two fundamental parts. The first part is the motion equations for vehicle based on Newton's second law. The second part is the torque dynamics of the traction motor. These parts are affected by outer conditions such as adhesive coefficient, running resistance and gradient resistance. The each parts are presented by the numerical formula. To test the driving characteristics of the developed model, we performed the simulations by dynamic system simulation software, "SIMULINK" and the results are given for several conditions.

Numerical modeling of uplift resistance of buried pipelines in sand, reinforced with geogrid and innovative grid-anchor system

  • Mahdi, Majid;Katebi, Hooshang
    • Geomechanics and Engineering
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    • 제9권6호
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    • pp.757-774
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    • 2015
  • Reinforcing soils with the geosynthetics have been shown to be an effective method for improving the uplift capacity of granular soils. The pull-out resistance of the reinforcing elements is one of the most notable factors in increasing the uplift capacity. In this paper, a new reinforcing element including the elements (anchors) attached to the ordinary geogrid for increasing the pull-out resistance of the reinforcement, is used. Thus, the reinforcement consists of the geogrid and anchors with the cylindrical plastic elements attached to it, namely grid-anchors. A three-dimensional numerical study, employing the commercial finite difference software FLAC-3D, was performed to investigate the uplift capacity of the pipelines buried in sand reinforced with this system. The models were used to investigate the effect of the pipe diameter, burial depth, soil density, number of the reinforcement layers, width of the reinforcement layer, and the stiffness of geogrid and anchors on the uplift resistance of the sandy soils. The outcomes reveal that, due to a developed longer failure surface, inclusion of grid-anchor system in a soil deposit outstandingly increases the uplift capacity. Compared to the multilayer reinforcement, the single layer reinforcement was more effective in enhancing the uplift capacity. Moreover, the efficiency of the reinforcement layer inclusion for uplift resistance in loose sand is higher than dense sand. Besides, the efficiency of reinforcement layer inclusion for uplift resistance in lower embedment ratios is higher. In addition, by increasing the pipe diameter, the efficiency of the reinforcement layer inclusion will be lower. Results demonstrate that, for the pipes with an outer diameter of 50 mm, the grid-anchor system of reinforcing can increase the uplift capacity 2.18 times greater than that for an ordinary geogrid and 3.20 times greater than that for non-reinforced sand.

역기전력 추정 기반 SMPMSM 센서리스 드라이브에서 저항 오차가 대역폭에 미치는 영향 (Influence of Resistance Error to the Bandwidth of Back-EMF Estimation based SMPMSM Sensorless Drives)

  • 김재석;설승기
    • 전력전자학회논문지
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    • 제21권5호
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    • pp.418-426
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    • 2016
  • This paper analyzes the effect of resistance error to the performance of sensorless drive system of surface-mounted permanent magnet synchronous machine (SMPMSM) based on the back-EMF observer. The analysis shows that the bandwidth of the entire sensorless drive system decreased in the low-speed region when using smaller resistance value than the actual one in the back-EMF observer. Even if the back-EMF observer invokes estimation error, the entire sensorless drive system does not make any steady-state position error. These characteristics may have positive effects such as extension of the low speed limit that goes further down in the sensorless drive. The validity of the analysis is verified by the experimental setup comprising the MG set.

회전자 저항 변동을 보상한 유도전동기의 센서리스 백터 제어 (Sensorless Vector Control of Induction Motor Compensating the variation of rotor resistance)

  • 박창훈;김광연;이택기;현동석
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1991년도 추계학술대회 논문집 학회본부
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    • pp.140-143
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    • 1991
  • This paper describes a compensation method for the rotor resistance variation of induction machines in speed sensor-less vector control system using MRAS(model reference adaptive system). In case of rotor resistance variation, the analysis of the conventional speed sensor-less vector control system using MRAS is presented and the compensation method for rotor resistance variation using Fuzzy logic is proposed. In order to confirm the performance of the proposed algorithm, computer simulation is performed.

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Ti Self-Aligned Silicide를 이용한 Contact에서의 전기적 특성 (Electrical Characteristics of Ti Self-Aligned Silicide Contact)

  • 이철진;허윤종;성영권
    • 대한전기학회논문지
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    • 제41권2호
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    • pp.170-177
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    • 1992
  • Contact resistance and contact leakage current of the Al/TiSiS12T/Si system are investigated for NS0+T and PS0+T junctions. SALICIDE (Self Aligned Silicide) process was used to make the Al/TiSiS12T/Si system. Titanium disilicide is one of the most common silicides because of its thermal stability, ability to form selective formation and low resistivity. In this paper, RTA temperature effect and Junction implant dose effect were evaluated to characterize contact resistance and contact leakage current. The TiSiS12T contact resistance to NS0+T silicon is lower than that to PS0+T silicon, and TiSiS12T of contact leakage current to NS0+T silicon is lower than that to PS0+T silicon. Contact resistance and contact leakage current of the Al/TiSiS12T/Si system by this method were possible for VLSI application.

알루미늄 판막과 유리섬유를 합지한 구리방근시트와 폐타이어 용융액상 도막방수재를 이용한 옥상녹화 복합방수공법 (Compound waterproofing method of green roof using copper barrier sheet and recycled tire melting liquid waterproofing material that reinforced treatments are valve and glass fiber mesh.)

  • 김영찬;조일규;최성민;김영찬
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2008년도 추계 학술논문 발표대회
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    • pp.173-178
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    • 2008
  • This is green roof bottom system which composed by aluminum valve and glass fiber together as major reinforcement, so the cooper sheet can have root proof, and using recycled tire gel-type membrane waterproofing system which dost not contains VOCs. The copper sheet reduce the plants' root growing, so it helpes to maintain the waterproofing layer and stability of root proofing. Gel type membrane waterproofing system can do waterproofing, stress dispersion, and reducing leakage expansion. So those two materials can help each other to make green roof bottom layer would have the stability and durability.

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