• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.3
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• pp.122-129
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• 2004

In plastic working, as working becomes speedy, automatic and working condition deteriorates, the increase of forging working has been remarkable. Therefore, we need the estimation of mold lift in detail, in order to counterplan of effective mold life extension. In this study, on the SKH51, mold steel which is forged by cold working and the KCW1, tool steel of low alloy, we estimated mold life on the base of FEM analysis and investigated mold lift by low cycle fatigue test. Also, this paper suggested a new method of estimation of mold lift.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.298-306
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• 1993

A portable torque and power measurement system for small farm equipment based on instrumented pulley was developed. The prototype pulley was machined from mild steel, with spokes serving as strain beams. Strain gages mounted to the spokes sense the bending strain due to the torque and convert this into millivolt output. Calibration results showed the torque-millivolt relationship was linear, while hysterisis and error were less than 1% fs. For power measurements, an additional tachmeter with dcvoltage output is necessary. With the tachometer , error in power measurement was +-1.03W or 0.2% fs. Field tests showed that for ease of installation, no machine alteration needed and safety, this system had advantage over other methods for small farm equipment.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1296-1299
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• 2001

In this paper, a simple, novel approach is proposed for a variable hysterisis band current controller which uses feedback techniques to achieve constant switching frequency with good dynamic response. The simulation result shows constant switching frequency and consequenctly the load current ripple decrease.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.717-720
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• 2001

Ferroelectric lead ziroconate titanate (PZT) thin film were fabricated on the different bottom electrodes. Both Ru and Ru/RuO$_2$bottom electrodes were deposited by RF-magnetron sputteirng method. The structure phase and surface morphology of the PZT thin film were largely affected by the bottom electrode. It was observerd that used of Ru/RuO$_2$double electrode reduced leakage current and better ferroelectric properties compare with RuO$_2$bottom electrode. From these results, Ru/RuO$_2$hybride bottom electrode is thought to be the available structure for the bottom electrode.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1206-1208
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• 2001

Direct torque control(DTC) of AC motor has the fast torque and flux dynamic responses even though it has very simple scheme to implement. DTC is also very simple in its implementation because it needs only two hysteresis comparators and switching vector table for both flux and torque control. The amplitude of hysteresis band greatly influences on the drive performance such as flux and torque ripple, switching frequency and current harmonics. Therefore, authors analysis flux and torque hysteresis bands is suggested considering switching frequency and harmonic distortion of currents.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.1
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• pp.5-11
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• 2008

To study the effects of $H_2$ gas on AIN insulation thin film, we prepared AIN thin film on Si and GaAs substrate by means of reactive sputtering method using $H_2$ gas as an additives, With treatment conditions of $H_2$ gas AIN thin film shows variable electrical properties such as its crystallization and hysterisis affected to electrical property, As a results, AIN thin film fabricated on Si substrate post-treated with $H_2$ gas for 20 minutes shows much better an insulation property than that of pre-treated, And AIN film treated with $H_2$ gas comparing to non-treated AIN film shows a flat band voltage decreasment. But In GaAs substrate $H_2$ gas does not effect on the flat band voltage.

• Journal of the Korean Home Economics Association
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• v.27 no.1
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• pp.1-8
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• 1989

In order to investigate the mechanical properties such as tensile, bending, shearing, thickness and weight of the wool fabrics were measured by KES-F system. Samples were classified into blend ratio, weave type, fabric count. Blend ratio was classified into two groups, which are P/W blended fabric (p=63~65%, w=35~37%) and all wool fabric. Weave type was classified into four groups, which are plain, 3 harness twill, 4harness twill, satin. Cloth count was classified into three groups, which are loose, medium, tight. Statistical analysis was performed using T-test, F-test. The results were as follows; 1. There was significant difference in the thickness, tensile, bending, shearing according to the blend ratio. 2. According the weave, there was significant difference in the bending, weight and thickness in the P/W blended fabrics. There was significant difference in the tensile, weight, thickness, bending, shearing, shearing hysterisis (2HG) in the all wool fabrics. 3. There was significant difference in the shearing properties according to the fabric count.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.05b
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• pp.135-141
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• 2000

The physical, electrical and piezoresitive characteristics of CrN(chromiun nitride) thin-films on silicon substrates have been investigated for use as strain gauges. The thin-film depositions have been carried out by OC reactive magnetron sputtering in an argon-nitrogen atmosphere(Ar-(5~25 %)$N_2$). The deposited CrN thin-films with thickness of $3500{\AA}$ and annealing conditions($300^{\circ}C$, 48 hr) in Ar-10 % $N_2$ deposition atmosphere have been selected as the ideal piezoresistive material for the strain gauges. Under optimum conditions, the CrN thin-films for the strain gauges is obtained a high electrical resistivity, $\rho=1147.65\;{\mu}{\Omega}cm$, a low temperature coefficient of resistance, TCR=-186 ppm/$^{\circ}C$ and a high temporal stability with a good longitudinal gauge factor, GF=11.17.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.8
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• pp.747-756
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• 2007

The hydropneumatic suspension units, which have applied to the tracked vehicles, have the spring and damping function in the unit. The nonlinear characteristics such as roadwheel rotation effects, gas behavior changes, hydraulic damping characteristics, hysterisis, and frictional forces have been ignored or simplified to analyze the mathematical models in many areas. This study describes the dynamic characteristics and the nonlinear behaviors of hydropneumatic suspension unit considering the nonlinear effects such as the nonlinear spring and nonlinear damping through the simulation and the experiment. The utility of nonlinear analysis through the higher-order spectral analysis is also presented.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.10
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• pp.122-127
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• 2012

A nano-electro-mechanical (NEM) memory simulator has been developed by using Matlab. The simulator can be used for the prediction of hysterisis curves, applied forces, steady- or transient-state behavior, program/erase energy consumption and potential energy. Predicting NEM memory behavior by simple user interface, the simulator will make the design of NEM memory cells simpler.