• 한국연소학회:학술대회논문집
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• 2012.04a
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• pp.223-226
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• 2012

Biomass to Liquid (BTL) is an attractive option for using biomass as an renewable energy. A syngas supplying system has been designed for BTL system, based on the Fischer-Tropsche (FT) process, and long-term operation test was conducted. The syngas supplying system is composed of a fluidized bed gasifier, gas cleaning and compression system, and methanol absorption system. Stable operation of more than hundred hours was achieved with several champaigns. In addition, a pilot scale biomass gasifier has been developed for 1 bbl/day BTL system and its performance was evaluated. Some preliminary results and current status of the development of BTL system will be presented.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.178-178
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• 2000

In this paper, intelligent methods using digital protection relay in power management and control system is developed in order to protect power systems by means of timely fault detection during operation and control at starting for induction motor which have various load environments and capacities in power systems. The digital protective relay was designed with DSP CPU(TMS320C31) to Protect and measure more quickly and precisely. The test result on the basis of KEMCl120 and IEC60255, show that the operation time error of the digital motor protection relay is improved within $\pm$5%. Also, we can control motors at starting according to starting types with simple method as programmable sequence editor. So we can improve the demerits of high cost and much manhour for rework.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.5
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• pp.617-624
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• 2007

This paper presents a novel quadstable monolithic mechanism (QsMM) which provides four stable equilibrium positions within its operation range. The quadstable mechanism has been realized from the use of both X- and Y-directional bistable structures which use curved snapping beams. A millimeter-scale brass mechanism was fabricated by ultra-precision milling to test the quadstability and the displacement-load behavior, and the prototype clearly demonstrated four distinct stable positions in its millimeter-scale planar operation. We discuss the design concept, finite element simulation for static and transient responses, fabrication by ultra-precision milling, and experimental measurement of the proposed quadstable mechanism.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.135-138
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• 2009

Quality evaluation of laser welded MCFC separator panels with large active area was performed. Lap joint was applied to produce stable air-tight seam weld by employing Nd:YAG laser. Results showed that surface contamination played a key role to form weld defects at the joint interface. However, there was no evidence that weld width at the lap joint changed after the stack operation time of 2,890h. Test results also revealed that the reinforcement values which were measured on the weld line after long time operation, were stable.

• Journal of the Korean Society of Industry Convergence
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• v.4 no.3
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• pp.263-266
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• 2001

In this paper, intelligent methods using digital protection relay in power SCADA system is developed in order to protect power systems by means of timely fault detection during operation and control at starting for induction motor which have various load environments and capacities in power systems. The digital protective relay was designed with DSP CPU(TMS320C31) to protect and measure more quickly and precisely. The test result on the basis of KEMC 1120 and IEC60255, show that the operation time error of the digital motor protection relay is improved within ${\pm}5%$. Also, we can control motors at starting according to starting types with simple method as programmable sequence editor. So we can improve the demerits of high cost and much manhour for rework.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.1059-1061
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• 2002

A FE model is to develop a personalized biomechanical model of the scoliotic spine that will allow the design of clinical test providing optimal estimation of the post-operation results. A flexible multi-body model of the spine including rib cage, clavicle, and scapular was developed to simulate several mobility simulations. Vertebrae, clavicle and scapular were represented using rigid bodies and ribs and sternum were modeled as flexible bodies. Kinematical Joints and spring elements were used to represent the intervertebral disc and ligaments respectively. Postero-anterior and lateral radiographics of a scoliotic spine were used to represent a 3D reconstruction. CT data for same patient were also used to verify vertebrae rotation driven from postero-anterior and lateral radiographic images. Simulated results showed good reducibility almost uniformly distributed along the spinal segments. It was also found that boundary and loading conditions, required to mimic the operation procedures, were proven to be very sensitive parameters to its results rather than its mechanical properties

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.6-9
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• 2008

The efficiency and life time of the proton exchange membrane (PEM) fuel cell system is critically changed with its humidity which should be maintained properly during dynamic operation. Membrane humidifier is required to regulate proper humidity level for the design point of the PEMFC system. In this study, we presented the performance of the cylindrical membrane humidifier which is operated as water-to-gas. Dry air pressure, liquid water flow temperature, and air flow rate were chosen as the operating parameters. Humidity level is expressed with dew point.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.232-237
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• 2006

Operation deflection shapes(ODS) is defined as a motion of structure at particular frequency. The ODS is eligible to show any types of structural motions while the modes supply solutions only to linear and stationary motion. The principal vibration source of an auto teller machine(ATM) case was occurred due to resonance which was found by modal analysis. To reduce the vibration of ATM case, the motion of the case was visualized using ODS analysis, which can suggest how to modify the structure. As a result the vibration of the ATM case was greatly reduced with a stiffening bar between the opposite plates.

• 전기의세계
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• v.18 no.2
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• pp.7-14
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• 1969

From the first customer located right at the substation to the last customer at the end of the line, voltage must be held within close limits, so the voltage regulation is more important than the thermal limit. On a typical distribution system during the peak load period, the voltage drop may be serious enough to cause unsatisfactory operation of home appliances in the residential area, and present many problems to manufacturing industries, where the voltage must be maintained within close limits to insure smooth operation. Among all the factors contributing to voltage drop in the distribution system, the voltage drop in the distribution transformer may account for 30% of this figure. If we can eliminate this factor, the power companies can provide better quality electricity to more customers with the existing distribution facilities, thus saving on initial investment costs. Taking all these problems into consideration, the author undertook the design of a capacitive transformer which would give zero voltage drop at rated load and at 80% lagging power factor while incorporating overload features to withstand 400% overload for at least 100 seconds. The following are the results obtained through design, manufacture and test of an initial experimental transformer built with these specific purposes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.4
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• pp.769-779
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• 2015

In this paper, the ideal standard design and construction of plant factory systems with the Green IT technologies is proposed. For feasibility and problem analysis, a container-type plant factory which was integrated with hardware and software of elemental technologies was operated as a test bed. This operation testing and research will be the foundation of the future construction and operation of large plant factories.