• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1617-1620
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• 2008

The effects of the temporal and permanent bright image stickings were examined under variable panel working gas pressure in the 42-in. ac-PDP with a high Xe (11 %) content. In the cells with and without temporal and permanent bright image stickings, the display luminance, firing voltage, and Vt closed curve were measured relative to the working gas pressure. With a decrease in the working gas pressure, the temporal bright image sticking was observed to be reduced, whereas the permanent bright image sticking was observed to be deteriorated.

• Journal of Mechanical Science and Technology
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• v.17 no.12
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• pp.1835-1843
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• 2003

This paper introduces the development of the caliper system for a geometry PIG (Pipeline Inspection Gauge). The objective of the caliper system is to detect and measure dents, wrinkles, and ovalities affect the pipe structural integrity. The developed caliper system consists of a finger arm, an anisotropic permanent magnet, a back yoke, pins, pinholes and a linear hall effect sensor. The angle displacement of the finger arm is measured by the change of the magnetic field in sensing module. Therefore the sensitivity of the caliper system mainly depends on the magnitude of the magnetic field inside the sensing module. In this research, the ring shaped anisotropic permanent magnet and linear hall effect sensors were used to produce and measure the magnetic field. The structure of the permanent magnet, the back yoke and pinhole positions were optimized that the magnitude of the magnetic field range between a high of 0.1020 Tesla and a low of zero by using three dimensional nonlinear finite element methods. A simulator was fabricated to prove the effectiveness of the developed caliper system and the computational scheme using the finite element method. The experimental results show that the developed caliper system is quite efficient for the geometry PIG with good performance.

• Journal of the Korean housing association
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• v.15 no.1
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• pp.33-40
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• 2004

Considering the present development situation of rental apartment since 1982, the supply of rental housing for low-income dwellers has contributed a amount of quantities, but has been deficient qualities in housing policy. To propose the device of remodeling for low-income dwellers in deteriorated apartment, this study investigated the energy consumption of central heating system and the characteristics of maintenance cost in permanent rental apartment. The results of evaluation of alternative heating systems by Life Cycle Costing in permanent rental apartment were as follows; From Life Cycle 15∼20 years by Present Worth Method, the economic heating system of remodeling is central heating system (heat source: B-C oil), unit heating system(natural gas), central heating system(natural gas) in order.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.39 no.2
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• pp.90-94
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• 2002

This paper is related to remote meter-reading using magnetic sensor. Scan system which is developed recently has week point of temperature, humidity, dust, oscillation To solve these problems, this study used magnetic action to measure the consumption of gas. Gas consumption was detected by interaction of a permanent magnet and hall element. Permanent magnet was pasted on rolling change-gear in normal gas meter and hall sensor was pasted on the external wall of normal gas meter. This experiment proved high accuracy and wasn't influenced by temperature, humidity, oscillation and dust

• Transactions of Materials Processing
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• v.14 no.3 s.75
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• pp.224-232
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• 2005

The high-pressure die-casting is one of the most effective methods to produce a large amount of products in short cycle time. This process, however, has a problem that the gas porosity defect appears easily. The generation of gas porosity is known mainly due to the air entrapment during the injection stage. Most of numerical simulations for the molten metal flow pattern observations have done in the treating of one phase fluid flow but the gas-liquid interface is essentially multi- phase phenomenon. In this paper, the two-phase fluid flow numerical simulation methods have been adapted to predict the gas porosity generations in the molten metal. The accuracy and the usefulness of the new simulation module have been emphasized and verified through some comparison experiments.

• Journal of the Korean Institute of Gas
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• v.5 no.3 s.15
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• pp.9-14
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• 2001

현재까지 국내에서는 지진에 대한 위험성을 인식하고 건축물 및 교량등에 대한 내진설계 연구가 활발하게 진행중이지만 지중에 매설된 관에 관한 연구는 미약한 실정이다. 지중매설관 중 가스관의 파손은 주변의 환경과 인명에 심각한 영향을 줄 수도 있으므로 인명보호와 타시설의 보호를 위해서는 가스관의 내진설계에 대한 검토가 요구된다. 본 연구에서는 지중매설관중 가스관의 내진성을 검토하기 위해서 가스관의 파손을 일으키는 원인 중에 하나인 액상화에 의한 영구지반변형에 대하여 매설관의 거동을 분석하였다. 이를 위하여 외국의 사례를 분석하고 우리나라 가스관에 대한 해석을 수행하여 지진에 대한 안정성을 검토하였다.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.919-920
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• 2007

Currently national High Voltage Gas Insulated Switchgear (GIS) operating mechanism is made up of spring operating mechanism or hydraulic operating mechanism. On the contrary, advanced technology trend in foreign countries replace current mechanical mechanism with electrical motor-drive mechanism that leads to participate GIS bid and increase sales with the point of simplification of driving system and IT application. Therefor it is essential to develop high voltage GIS using the motor-drive system to develop national heavy electric machine industries and catch up the technology to the advanced level. This paper therefore presents design and analysis of permanent synchronous motor for high voltage GIS, verifies the performance by the experimental test.

• Proceedings of the KIPE Conference
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• 2017.11a
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• pp.69-70
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• 2017

This paper presents design of control system for permanent magnet synchronous generator(PMSG). The gas engine make rotating mechanical energy from gas fuel energy. The rotor of synchronous generator is connected to axis of engine. And it converts the mechanical energy to the electrical energy. The control system of PMSG helps the electrical energy to flow to grid. the single phase pfc rectifier controls the DC-link voltage by controlling the current of filter inductor. If the DC-link voltage is higher than the voltage reference, the filter current could be controlled to flow to grid. The three phase inverter controls the stator current of generator. The direction of the current is controlled depends on motoring or generating mode. The feasibility of the grid-connected PMSG is verified by the experimental results with 1kW prototype.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1042-1044
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• 2003

High speed PM machines are being developed as motor/generators for gas-turbine generator sets in smaller power sizes, and as motors for number of applications including gas compressors, machine tools and turbo molecular pumps. Due to the high peripheral speed of the rotor and the relatively high conductivity of the magnets used, rotor eddy current loss can be substantial. This paper deals with the calculation of rotor eddy-current losse in permanent magnet(PM) high speed motor using the analysis of harmonics.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.939-941
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• 2003

High Speed permanent magnet machines are currently being developed for a number of applications including gas turbine power plants, air conditioning systems, machine tools, gas pumps, high performance vacuum pumps, flywheel energy storage systems, aircraft fuel pumps, and so on. Using a high-speed machine eliminates the necessity of the mechanical gearbox and could certainly increase the system efficiency and reduce the total cost. In addition, a high-speed machine has the advantage of small dimension and low weight, i.e. low weight to power and volume to power ratio. This paper presents a review of some important applications (mostly still under development) where high-speed machines arc used, highlighting the advantages of the technology in each case.