• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.101-104
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• 1996

A new detecting system for moving objects of coastal region has been designed by directional antenna and driving circuits. The designed system has been investigated by CAD for linear and planar antenna arrays of various radiating elements for antenna simulations and by P-spice of device simulations. For detecting the displacement of moving objects, we constructed four wideband dipole antenna, diode switching circuit, mixer, filter and amplifier. The results of antenna receiver were shown a possibility of distance measuring system through phase difference of radiation patterns in antenna simulation

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.4
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• pp.454-459
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• 2013

The authors study a novel type of elevator emergency stop device which enables to soften impact force at an emergency halt. A new structure of emergency stop devices has been already proposed by our laboratory and also its characteristics has been already proposed by our laboratory and also its characteristics has been shown by digital simulations[1]. In order to confirm the actual effects of our proposed emergency stop device, we have made up a simulator having the same characteristics as the conventional emergency stop device to accomplish the experiments from now on. In this paper, this process is introduced.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1993.11a
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• pp.29-34
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• 1993

In this paper, we used one-dimensional process simulator, SUPREM-II, and two-dimensional device simulator, MINIMOS 4.0 to extract optimal process parameter that can minimize degradation of device characteristics caused by process parameter variation in the case of short channel nMOSFET and pMOSFET device. From this simulation, we have derieved the relationship between process parameter and device characteristics. Here we have presented a method to extract process parameters from design trend curve(DTC) obtained by process and device simulations. We parameters to verify the validity of the DTC method. The experimental result of 0.8 $\mu\textrm{m}$ channel length devices that have been fabricated with optimal that reduces short channel effects, that is, good drain current-voltage characteristics, low body effects and threshold voltage of 1.0 V, high punchthrough and breakdown voltage of 12 V, low subthreshold swing(S.S) values of 105 mV/decade.

• Tribology and Lubricants
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• v.29 no.1
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• pp.7-12
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• 2013

Turbine power control devices at a nuclear / thermoelectric power plant lead to failure by creating mechanical shocks and strong vibrations that are due to the strong elasticity of a spring and the inertia of the valve face during its rapid movement to block steam. To ensure durability of the turbine power control device, which is the main component in the power plant, it is necessary to develop a device that can prevent such vibrations. In this study, a cushion mechanism is added to the head of the hydraulic servo actuator, which is a turbine power control device. Moreover, the cushion mechanism, which includes various modifies shapes and orifices is investigated dynamically through modeling and simulations.

• Proceedings of the IEEK Conference
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• 2000.06b
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• pp.306-309
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• 2000

In this work, we investigated A1 cluster deposition on Al (100) surface using molecular dynamics simulation. A result of simulations showed that large cluster with low energy was proper for good surfaced-films without craters at the low temperatures. We investigated the maximum substrate temperature and the time taken for substrate temperature to reach its maximum as a function of cluster size in the case of the same total energy and in the case of the same energy Per atom. The correlated collisions play an important role in interaction between energetic cluster and surface, and as cluster size and cluster energy increases, the correlated collisions effect affects interaction between energetic cluster and surface.

• Journal of the Korean Society of Visualization
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• v.21 no.3
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• pp.23-32
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• 2023

This study aims to explore the heat transfer and flow phenomena inside an instant water heater and the influence of the design parameters of the water heater on the heating performance was investigated by 3-D numerical simulations considering heat convection. The design parameters are the heating ceramic dimension, the power of the heating device, and the water flow rate. The results show that a reasonable space for the heating device is required to optimize the heating performance. It is desirable to design higher heating device as possible for a given electric power. There exists a critical water flow rate that best meets the heating performance. The change in electric power has no impact on the flow phenomena and heating performance.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.1
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• pp.887-894
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• 2018

We investigated the position controlling C60 fullerene encapsulated into a graphene-nanoribbon trench via classical molecular dynamics simulations. The graphene-nanoribbon trench can provide nanoscale empty spaces, and a C60 encapsulated therein can be considered as media for a nanoelectromechanical shuttle device. The classical molecular dynamics simulations presented here provide information on the potential application of a graphene-nanoribbon trench in a C60 shuttle device. Driving forces applied to C60 resulted in its motion toward the edges of the graphene-nanoribbon trench, the suction forces induced at both edges were balanced with the driving forces, and finally, the C60 fullerene gradually settled on the edges of the graphene-nanoribbon trench after several oscillations. The results of the present simulation suggest the importance of graphene-nanoribbon trenches encapsulating fullerenes in a wide range of applications in the field of nanotechnology.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.1
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• pp.49-57
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• 2010

This paper describes the design, construction, and fundamental testing of a precision rotational device that utilizes piezoelectric elements as a source of driving force and impact drive mechanism as a driving principle. A novel device structure is designed and the numerical simulations about the static displacement, stress distribution, and mode shape of the designed structure are performed. A fabricated rotational device has been rotated successfully by applying saw-shaped voltages to the piezoelectric elements. The one-step rotational angle was $0.44{\times}10^{-3}$ rad at the applied voltages of 80V. The angular velocities of the device were revealed to be increased as the driving frequency and voltage were respectively increased and the preload was decreased. The device has a feature that it can be translated as well as rotated. An experimental result shows that the device was translated by ${\pm}4.56{\mu}m$ maximum when the 120V sinusoidal voltages with a phase difference of $180^{\circ}$ were respectively supplied to two piezoelectric elements.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1065-1070
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• 2007

The effects of hot carriers and self-heating on the electrical stability of p-channel TFTs have been analysed combining experimental data and numerical simulations. While hot carrier effects were shown not to induce appreciable degradation, self-heating related instability was found to more seriously affect the device characteristics. New models have been developed to explain the reported results.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.10
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• pp.20-26
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• 1993

The base-collector capacitance of an npn bipolar transistor in bipolar or BiCMOS technology has significant influence on the switching performances, and comprises pnjunction component and MOS component. Both components have complicated dependences on the isolation oxide structure, epitaxial doping density, and bias voltage. Analytical/empirical formulas for both components are derived in this paper for a generic isolation structure as a function of epitaxial doping density and bias voltage based on some theoretical understanding and two-dimensional device simulations. These formulas are useful in estimating the effect of device isoation schemes on the switching speed of bipolar transistors.