• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.157-158
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• 2014

In this paper, a design method for a compact CPW-fed slot antenna using SRRs(split-ring resonators) is studied. The structure of the proposed slot antenna is a rectangular slot antenna loaded with SRR conductors inside the slot to reduce the antenna size. Optimal design parameters are obtained by analyzing the effects of the gap between the SRR conductors and slot, and the width of the SRR conductors on the input reflection coefficient characteristic. The optimized compact slot antenna operating at 2.45 GHz band is fabricated on an FR4 substrate with a dimension of 36 mm by 30 mm. The length of the proposed compact slot antenna is reduced by 14.3% compared to that of a conventional rectangular slot antenna. Experiment results show that the antenna has a desired impedance characteristic with a frequency band of 2.4-2.49 GHz for a VSWR < 2.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.10
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• pp.2265-2272
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• 2013

In this paper, a dual-band circular ring monopole antenna with stub and ground slot for is proposed WLAN(Wireless Local Area Networks) applications. The proposed antenna is based on a planar monopole design, and composed of one circular ring of radiating patches, and modified feed line, and rectangular slot in the ground plane for dual-band operation. To obtain the optimized parameters, we used the simulator, Ansoft's High Frequency Structure Simulator(HFSS) and found the parameters that effect antenna characteristics. Using the obtained parameters, the antenna is fabricated, and the return loss coefficient, gain, and radiation patterns are determined for WLAN application.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.886-891
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• 2001

This paper present the results of finite element analysis to examine the sloshing characteristics of the cylindrical and rectangular tank partially fluid-filled. The sloshing characteristic for the existence and the non-existence of the baffle are investigated and the results compared with the references. For the rectangular tank, the vertical displacements are used to study of the sloshing characteristics. But for the cylindrical tank, the damping factors obtained from the vertical displacements of free surface with the depth of ring baffle are usedto study of the sloshing characteristics. The adaptive meshing method in the ABAQUS 5.8/Explicit is used for the sloshing analysis.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1988.10a
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• pp.18-23
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• 1988

This study on the elasto-plastic analysis of spherical shell by rigia element method is classified into two parts : (1) theoretical consideration on elasto-plastic analysis of spherical shell, (2) elastic and elasto-plastic analysis of spherical shell with the open stiff ring. In 1982, Y. Tsuboi proposed the new analytical method which is called the rigid element method, for analyzing the elasto-plastic behavior of wall-type precast concrete structures by applying the concepts of rigid bodies-sprins model (i．e., when structures reach their ultimate state of leading, they may be yield, collapsed ana crushed into pieces, and each part or piece of structures mar move like a rigid body.). In this paper, for improvement and expansion this rigid element method, it is proposed the adaptation equation of rectangular-shaped spherical element and rectangular-shaped spherical bending element developed by present authors, and the analytical procedure for the elastic and the elasto-plastic increment method of structures.

• Journal of radiological science and technology
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• v.20 no.1
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• pp.15-20
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• 1997

Unlike conventional CT scan, the helical CT scan uses continuous rotating CT equipment with a slip ring to move the patient's coach at a constant speed while continuously scanning. Slice sensitivity profiles in the Z-position(SSPz) using the conventional X-ray CT have a shape similiar to a rectangular wave, which slightly spreads out into plains below the mountain. However, in the helical CT, with an expansion of the base, the rectangular shape collapses and a mouatain-like shape can be seen. We need to investigate the fellowing factors in helical CT scanning;the ability to scan along the axis of the body, effective slice width, slice shape and the precision of coach velocity, Helical scanning with sprial X-ray track is different from the conventional scanning in terms of the principle of image reconstruction performed. We believe that the problems in helical scanning can be solved by understanding new the special parameters such as the bed moving speed and the interval of image reconstruction.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.44 no.4
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• pp.490-495
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• 1995

A bipolar junction transistor which exihibits 1000V breakdown voltage is designed and fabricated using FLR (Field Limiting Rings). Three dimensional effects on the breakdown voltage is investigated in the cylindrical coordinate and the simulation results are compared with the results in the rectangular coordinate. Breakdown voltage of the device with 3 FLR is simulated to be 1420V in the cylindrical coordinate while it is 1580V in rectangular coordinate. Bipolar junction transistor has been fabricated using the epitaxial wafer of which resistivity is 86 .OMEGA.cm and thickness is 105 .mu.m. Si$_{3}$N$_{4}$ and glass are employed for the passivation. Breakdown of the fabricated device is measured to be 1442V which shows better greement with the simulation results in cylindrical coordination.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.5
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• pp.473-480
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• 2013

This paper describes the design of a rectangular-type four-finger rehabilitation robot for flexibility rehabilitation of stroke patients' fingers and other patient's paralyzed fingers. The four-finger rehabilitation robot is composed of a body and each finger rehabilitation robot instrument. The four-finger rehabilitation robot could exercise four fingers (forefinger, middle finger ring finger and little finger) of patient for their rehabilitation. The four-finger rehabilitation robot instruments move according to the trace which spread out the patient's fingers and then turn them inward for the fingers' flexibility, while at the same time performing the force control with the reference forces for fingers' safety, simultaneously. A control characteristic test of the developed rectangular-type four-finger rehabilitation robot was carried out, and the results confirmed that the robot could be used for the flexibility rehabilitation exercise for the fingers of normal person and patients.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.5
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• pp.516-523
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• 2012

Stroke patients should exercise for the rehabilitation of their fingers, because they can't use their hand and fingers. The moving direction of thumb of five fingers is different that of four fingers (force finger, middle finger, ring finger, little finger). The thumb rehabilitation robot for rehabilitation exercise must be included a force control system, because robot can injure thumb by applying too much force. In this paper, the rectangular-type thumb rehabilitation robot was developed for stroke patient's thumb rehabilitation exercise of the flexibility rehabilitation exercise. The characteristic test of the developed rectangular-type thumb rehabilitation robot was carried out with normal men in their twenties. As a result, it is thought that the robot can be used for the flexibility rehabilitation exercise of stroke patient's thumb.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.3
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• pp.14-21
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• 2006

The unsteady vortex lattice method is used to model twisting and flapping motions of a rectangular flat plate wing. The results for plunging and pitching motions were compared with the limited experimental results available and other numerical methods. They show that the method is capable of simulating many of the features of complex flapping flight. The lift, thrust and propulsive efficiency of a rectangular flat plate wing have been calculated for various twisting angles and reduced frequency with an amplitude of flapping angle($20^{\circ}$). And the effects of the twisting on the aerodynamic characteristics of the flapping wing are discussed by examination of their trends.

• Tribology and Lubricants
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• v.18 no.1
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• pp.34-41
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• 2002

This paper presents the contact thermal behaviors of mechanical seals depending on the contacting face geometry. Using the finite element analysis, the temperature distribution, thermal distortion and leakage have been analyzed as functions of sealing gap and rotating speed of the seal ring shaft. The FE results indicate that the inclined contacting face may be more effective and stable based on the results of thermal characteristic analysis if the seal ring has been designed with a same thermal capacity between conventional rectangular sealing faces and inclined seating surface of seal rings.