• Progress in Superconductivity and Cryogenics
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• v.4 no.1
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• pp.84-88
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• 2002

The resistive fault current limiter (SFCL) is a very attractive device for power networks. But it has a serious Problem in using YBCO films for fault current limiter is inhomogeneities caused by imperpect manufacturing. So simultaneous quenches are a difficult problem which elements for current limiting are connected in series for increasing voltage ratings. We investigated extended electric field-current characteristics for current limiting element of YBCO film when O-130mT magnetic field is applied. And quench characteristics were investigated in over all element and between elements of YBCO films. From the experiments, it was shown that applied magnetic fields using solenoid coil induced uniform quench distribution for over all stripes and simultaneous quench in all elements for current limiting of YBCO film was realized. We have achieved resistive fault current limiter of 1.2kV/20A rating using magnetic field.

• Earthquakes and Structures
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• v.17 no.5
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• pp.489-499
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• 2019

Elastic-plastic behavior of nuclear power plant elbow piping under seismic loads has been conducted in this study. Finite element analyses are performed using classical Bilinear kinematic hardening model (BKIN) and Multilinear kinematic hardening model (MKIN) as well as a nonlinear kinematic hardening model (Chaboche model). The influence of internal pressure and seismic loading on ratcheting strain of elbow pipe is studied by means of the three models. The results found that the predicted results of Chaboche model is maximum, closely followed by the predicted results of MKIN model, and the minimum is the predicted results of BKIN model. Moreover, comparisons of analysis results for each plasticity model against predicted results for a equivalent cyclic loading elbow component and for a simplified piping system seismic test are presented in the paper.

• Steel and Composite Structures
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• v.46 no.2
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• pp.221-236
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• 2023

In order to study the seismic response of the main plant of steel reinforced concrete (SRC) structure of the CAP1400 nuclear power plant under the influence of different high-mode vibration, the 1/7 model structure was manufactured and its dynamic characteristics was tested. Secondly, the finite element model of SRC frame-bent structure was established, the seismic response was analyzed by mode-superposition response spectrum method. Taking the combination result of the 500 vibration modes as the standard, the error of the base reactions, inter-story drift, bending moment and shear of different modes were calculated. Then, based on the results, the influence of high-mode vibration on the seismic response of the SRC frame-bent structure of the main plant was analyzed. The results show that when the 34 vibration modes were intercepted, the mass participation coefficient of the vertical and horizontal vibration mode was above 90%, which can meet the requirements of design code. There is a large error between the seismic response calculated by the 34 and 500 vibration modes, and the error decreases as the number of modes increases. When 60 modes were selected, the error can be reduced to about 1%. The error of the maximum bottom moment of the bottom column appeared in the position of the bent column. Finally, according to the characteristics of the seismic influence coefficient αj of each mode, the mode contribution coefficient γj•Xji was defined to reflect the contribution of each mode to the seismic action.

• Earthquakes and Structures
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• v.18 no.5
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• pp.581-598
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• 2020

This paper aims to investigate the seismic behavior and influence parameters of the large-scaled thin-walled reinforced concrete (RC) tubular columns in air-cooled supporting structures of thermal power plants (TPPs). Cyclic loading tests and finite element analysis were performed on 1/8-scaled specimens considering the influence of wall diameter ratio, axial compression ratio, longitudinal reinforcement ratio, stirrup reinforcement ratio and adding steel diagonal braces (SDBs). The research results showed that the cracks mainly occurred on the lower half part of RC tubular columns during the cyclic loading test; the specimen with the minimum wall diameter ratio presented the earlier cracking and had the most cracks; the failure mode of RC tubular columns was large bias compression failure; increasing the axial compression ratio could increase the lateral bearing capacity and energy dissipation capacity, but also weaken the ductility and aggravate the lateral stiffness deterioration; increasing the longitudinal reinforcement ratio could efficiently enhance the seismic behavior; increasing the stirrup reinforcement ratio was favorable to the ductility; RC tubular columns with SDBs had a much higher bearing capacity and lateral stiffness than those without SDBs, and with the decrease of the angle between columns and SDBs, both bearing capacity and lateral stiffness increased significantly.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.6 no.3
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• pp.43-49
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• 1992

Forecasting of electric power demand has been a basic element for electric power system operation and system development, and it's accuracy has very strong influence on reliability and economical efficience of power supply. So, in this paper, long―term maximum electric power demand has been forecasted by using the triple exponential smoothing method initiated R.G.Brown. It has been regarded this method as high accuracy and operational convenience. The smoothing function is a liner combination of all past observations and the weight given to previous observations decreases geometrically with age.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.5
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• pp.285-290
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• 2015

The phase change memory material is an active element in phase change memory and exhibits reversible phase transition behavior by thermal energy input. The doping of the phase change memory material with Ga leads to the increase of its crystallization temperature and the improvement of its amorphous stability. In this study, we investigated the effect of GaGe sputtering power on the formation of the phase change memory material including Ga. The deposition rate linearly increased to a maximum of 127 nm and the surface roughness remained uniform as the GaGe sputtering power increased in the range from 0 to 75 W. The Ga concentration in the thin film material abruptly increased at the critical sputtering power of 60 W. This influence of GaGe sputtering power was confirmed to result from a combined sputtering-evaporation process of Ga occurring due to the low melting point of Ga ($29.77^{\circ}C$).

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.632-635
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• 2009

Nowadays renewable energy has undergone major development, however most renewable energy resources still have demerit which is under the influence of environmental factors that can not be set up the power plants or can not be generated the rated power. To wander from the point of environmental instability, the present paper looks at the tidal current energy which can supply regular electric power. It has an important merit which is more predictable than others, however the place which can be set up is limited and the turbine system must be optimized. The development of the optimized rotor blades design is urgent to obtain regular electric power using the tidal current energy. Therefore, the paper expands on this idea and presents a conceptual design of 100kW horizontal axis rotor blade for the tidal current turbine using blade element momentum (BEM) analysis. The compatibility of horizontal axis tidal turbine (HATT) is verified using a commercial computational fluid dynamics (CFD) code, ANSYS-CFX. This paper presents results of the numerical analysis, such as pressure, streak line and the performance curves with torque data for the inflow of the horizontal axis tidal current turbine (HATT).

• Journal of Families and Better Life
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• v.5 no.2
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• pp.127-144
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• 1987

The purpose of this study is to explore the family communication and power. Communication is a symbolic, transactional process in functional view . To say tat communication is a process implies a continuous interaction of an indefinite large number of variables with a concomitant, continuous change in the values taken by these variables. Finally the process implies change. Family functions include the primary functions of cohesion and adaptability and supporting functions of family images, themes, boundaries, and biosocial issues, The primary functions reveal concepts integrated family interaction and supporting functions, along with those of cohesion and adaptability, give shape of family life. The message system is the major element of communication process and influences both the form and the content of thier relationship and create and share meanings. The family-of-origin issues influence all aspects of family communication and account for many of the communication patterns, rules and networks. Power does not belong to an individual. rather it is a property of a relationship between two or more persons, Power, a system property is the ability of an individual to change the behavior of other members in a social system. Power operate transactionally in a family and any power maneuvers within it have a system wide effect. In order to study power in families , it is necessary to examine 1) family power operations 2) development of family power and 3) the communication of power strutegies. The research presented indicated that a rigid power structure, characterized by dominance and little sharing, restricts family flexibility reduce cohesion, and adversely affects satisfaction in families. power constantly changes as a family grows and develops within its system. Although power changes may be more obvious in children as they mature and more from a independent stated to an independent one, each of the parents experience egual or greater. Communication and activities take place that either enhance positively or negatively the images, themes, and degree of unity of cohesion the family desires. Power operated within a dynamic, growing, changing, interdependent transactional family system. Power struggle may develop when as issue becomes important to one or more family member. When this happens, and the rational exploration of alternatives ceases, various one-up power maneuvers usally follows, This affect family intimacy. a vital element in meaningful relationships . To resolve differences and not become the victim of another's power , one need to engage in constructive conflict since the ability to clearly and comfortably repudiate another is part of the achievement of intimacy.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1993-1995
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• 2000

In this paper, we calculate the magnetic field and analyze the inductive interference in conductive material around power transmission line. To compute induced eddy currents as well as magnetic fields, finite element method(FEM) is used for numerical calculation. The characteristics, transmission line height, conductive earth and mitigation wire are taken account of FEM analysis. This research also shows that mitigation wire reduces amount of eddy current in buried pipe line.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.5
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• pp.716-723
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• 2002

Heat transfer in linear motor driven stages for surface mounting device applications was investigated. A simple one-dimensional thermal resistance model (TRM) was introduced. In order to reduce three-dimensional nature to one-dimensional, a few assumptions and simplifications were employed suitably. A good agreement with a finite element heat transfer analysis in temperature profile was obtained. For validation, the analysis was compared with the measurement with respect to motor driving power. Overall discrepancy was less than 7$^{\circ}C$. The influence of two high thermal resistance parts, insulation sheet and thermal contact between the coil assembly and the mounting plate, was examined through the analysis. Additionally, the thermal resistance analysis was applied to another stage including an internal cooling-air passage, and was found available for this system as well. After validation, the cooling effect was surveyed in terms of motor power, and cooling-air and -water flow rate.