• 전기학회논문지P
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• 제55권3호
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• pp.128-132
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• 2006

The previous MCCs(Motor Control Centers) have the demerits of high cost and much manhour for rework because it is impossible for us to standardize the previous MCCs and they have many manual connections. The customers require the products which can operate with the SCADA system by digitalizing the functions of the current MCCs and the systematized products with capability of remote control. To solve these disadvantages and requirements, we developed the Intelligent Motor Control Center. This system has the various functions such as protection, measuring, and communication. Using these functions, we can monitor motor status through communication with the upper system and define the circuit for lowering connection costs according tn starting type and shortening the manufactural period by the graphic editor. The development of this system results in establishment of the competitive structure with domestic area and Perfect automatic monitoring through linkage with the SCADA system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.125-127
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• 2003

The single phase switched reluctance motor(SRM) is more simpler and robust in the structure than poly phase SRM. It has the merits that it reduces the switching elements and the energy density per volume is very high. Recently, it has been researched and developed in various types and starting method due to the technique of power electronics and the computer added design. The single phase SRM is tried to apply to many industrial appliance field to substitutethe the induction motor by the single phase SRM. On the previous studies, we decided the design parameters of the single phase SRM for the blower driver to adapt the design method of the conventional machine and the poly phase SRM. In this studies, it is proposed the conditions to decide the optimal pole arcs because the stator and rotor pole arcs is very important in the characteristics of the single phase SRM. For this reason, it is analysed the characteristics of current on/off angle vs. pole arc, pole arcs vs. average torque.

• The Korean Journal of Ceramics
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• 제2권4호
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• pp.251-256
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• 1996

Effect of mixed grinding with a planetary ball mill of starting materials before heat treatment on the crystal structure and superconduction properties in the YBaCu composite oxide was studied. The size reduction of powders too place in the early stage of grinding, followed by aggregation of the resultant fine particles. The uniformity of the composition in the mixture was improved with grinding, which later decreased in the crystal grain size and well distribution of twin phase in the sintered bodies. The critical current density of the sintered bodies obtained from the mixture ground for 60 minutes showed the maximum value about 150 A/$\textrm{cm}^2$, while critical temperatures were around 90K and were independent of the grinding time.

• 한국시스템다이내믹스연구
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• 제9권2호
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• pp.27-43
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• 2008

This study investigates market barriers in increasing the market share of Alternative Fuel Vehicles (AFVs). In particular, this study first conceptualizes the AFVs market model with the aid of generic system archetypes suggested by Wolstenholme. Among four generic system archetypes suggested by Wolstenholme, the market structure of AFVs can be explained by the 'relative achievement' archetype. Starting from the generic system archetype, this study extends the model boundary step by step to take account of various model assumptions necessary to simulate the model numerically. If there is a significant network effect on vehicle operating costs, it is difficult to achieve the shift to AFVs even in the long term without a policy intervention because the car market is locked into the current structure. There are several possible policy options to break the 'locked-in' structure of the car market, such as subsidies on vehicles, subsidies on fuels, and a niche management policy.

• 진공이야기
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• 제3권4호
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• pp.19-23
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• 2016

Angle resolved photoemission spectroscopy (ARPES) is a powerful technique which can directly visualize the electronic structure of solid in detail including many-body interaction information. However, ARPES has a certain limitation in applying control parameters such as doping or pressure, which helps to dig out the clue to understand the desired phenomena or the target system. During ARPES experiment, the control parameter is the temperature only. Other parameters especially electric- and magnetic- field cannot be applied. Recently introduced surface-electron doping technique highlights new avenue to overcome such limitation. In this article, starting from introducing basic concepts of ARPES and its current status, the power of new technique will be demonstrated when it is combined to ARPES by introducing recent results on iron based superconductors.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.516-520
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• 1991

This paper presents a comparative analysis of two inverter power supply topologies for induction heating and melting applications. The comparison is based on criteria such as resonant condition, component ratings, minimum and maximum operating frequencies, operation under varying load conditions, inverter starting current, and diode reverse recovery time. The voltage source series/parallel resonant inverters are found to offer the best overall performance with respect to converter utilization.

• 한국환경과학회지
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• 제4권2호
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• pp.169-180
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• 1995

This Daper presents effective simulation of the dispersion of thermal discharge which can be relesed at Boryong power plant. Applied numerical models are finite difference method for hydrodynamic analysis and Masch-model comprised of conditions for ambient current velocity. Application of these models is done in Cheonsu Bay Summing up the results of this study are as follows; 1. It is found that the result for measurements of temperature appears high at southwardly Songdo on flood. The reason is that tidal currents which flowed north direction were accompanied with southwardly dispersed thermal discharge. A minute Particle of thermal Plume has a tendency to dispels inward Deacheon Bay. 2. According to the results of numerical experiment, maximum distance for thermal discharge dispersion appeared 10.8 km at lower part and 8.6 km at upper part with power plant outlet as starting point. 3. Comparative the numerical simulation and Airbone Multispectral Scanner indicated that thermal discharge should be verified separative phenomena. The simulated results were compared with field data set showing good agreement. It is concluded that these model can be simulated well.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2009년도 정기총회 및 추계학술대회 논문집
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• pp.268-270
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• 2009

This paper proposes a simple starting method to arrange the rotor position of the blushless DC motor (BLDC) without additional sensors and any information of motor parameters. Both the stator current and time period for arranging the rotor position can be easily adjusted by modulating a pulse width of switching devices. Using the proposed method, it is demonstrated experimentally that the BLDC starts up very smoothly.

• 한국정밀공학회지
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• 제25권9호
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• pp.53-58
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• 2008

The traditional engine valve train in a combustion engine is the mechanically driven camshaft system that provides one-fixed valve timing. The variable valve timing (VVT), however, is highly required to achieve the significant improvement in fuel economy. To achieve VVT in combustion engine, the solenoid type of actuator had been developed in past years, but it requires current in all operation period, the starting is difficult and the efficiency is low. In this paper, a new linear actuator using permanent magnet (PM) is proposed and verified its feasibility by finite element (FE) analysis.

• 복식
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• 제52권8호
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• pp.15-27
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• 2002

To set the measurements of bras for women in their 20s, considering the comfortableness in wearing and tightness, this paper conducted a questionnaire survey concerning breasts and bras as well as measurements of body and contact surface pressure. Easier and more accurate method of determining cup sizes based on the breast circumference is recommended to make up for the problem of current bra size system that can falsely measure cup sizes. Lower chest circumference was set at 5 cm equal intervals, and the breast circumference applicable to the cup size was set starting from the standard, 18 cm (A-cup), at 2 cm equal intervals, which gave the best coverage (88.1%).