• Disaster Prevention Review
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• v.15 no.4
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• pp.142-143
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• 2013

• Proceedings of the Zoological Society Korea Conference
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• 1994.10a
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• pp.210.1-210
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• 1994

No Abstract, See Full Text

• Journal of the Korean Society of Safety
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• v.21 no.3 s.75
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• pp.8-15
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• 2006

It is no wonder that mechanical structures are accompanied by problems related to corrosion after being exposed to long hours of work. Corrosion of mechanical structures has been the most serious problem in the field of industry. The present study employed a laser beam irradiation test to improve the corrosion resistance of degraded Cr-Mo steel, which was used for more than 60,000 hours. To find the optimum irradiation test condition for the corrosion resistance of degraded Cr-Mo steel, hardness and residual stress measurements, micro-structural observation, and the electrochemical potentiokinetic reactivation (EPR) tests were performed with changes in laser beam test conditions including laser beam output, diameter, and velocity. Thus, the present study indicates that the optimum test condition and absorption energy for a laser beam test need to be determined to enhance corrosion resistance of degraded Cr-Mo steel.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1656_1657
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• 2009

This paper presents a new method for estimating rotor resistance of induction motor. The rotor resistance changes dramatically with temperature and frequency. Speed is controlled by PID as it is simplest and most intuitive control method. The change in rotor resistance has a great influence on the performance of IM. In this paper rotor resistance is estimated using Non Linear Disturbance Observer. The model uncertainty and system non linearity are treated as disturbance in this method. Using NDO it does not require an accurate dynamic model to achieve high precision motor control. Controller with NDO has more superior tracking performance. Simulation results are presented to show the validity of the proposed controller.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2004.10a
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• pp.36-38
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• 2004

Ethaboxam is a new fungicidal active ingredient that inhibits growth of plant pathogens specifically belonging to Oomycetes with protective, curative, systemic and translaminar activity in plants. Modes of action studies revealed that ethaboxam simultaneously inhibits cytoskeleton formation and mitochondrial respiration of Phytophthora infestans at low concentrations. There have been no indications of resistance development when tested for baseline resistance monitoring to 261 isolates of P. infestans in Korea and Europe and 150 populations of Plasmopara viticola populations in Europe for 3 years since 2000. In a selective study with vine trees artificially inoculated with P. viticola repeatedly for 10 generations in greenhouse, there have been no changes in sensitivity to ethaboxam among four natural populations of P. viticola. Furthermore, ethamoxam has not shown any cross resistance with azoxystrobin, mefenoxam, dimethomorph and cymoxanil. Based on the study results from modes of action and resistance development, ethaboxam appears to be unlikely to develop resistance in field applications.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.67-67
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• 2010

PV module has many power loss factor in the site. Among them, one thing is series resistance. Especially interconnection ribbon resistance is one of the power loss. In this paper, we study interconnection ribbon resistance of the PV module material. In the field, high temperature can pile ribbon resistance on the PV modules. We can do better choice in the optimum use of ribbon through checking relation of ribbon dimension and resistivity. From this point of view, different solder type and dimension was treated.

• Journal of the Korean Solar Energy Society
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• v.29 no.4
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• pp.1-6
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• 2009

This paper estimates numerically cells the electrical characteristics of the PV module with environmental changes such as shunt resistance, series resistance, temperature, irradiance. Series resistance $R_s$ including diode characteristic resistance $r_d$ is derived from the p-n junction diode model. I-V characteristics of this model with series resistance $R_s$ are simulated on Matlab. Finally, theoretical I-V characteristics are compared with those of solar simulator. Those results agreed well within the manufacturer's maximum error range 3%

• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.2
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• pp.92-98
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• 2019

Accurate estimation of motor parameters is required in some motor control applications. For example, the value of stator resistance is required for stator flux-oriented control mostly used in doubly fed induction generator systems. Stator resistance is not a constant value and continuously changes due to the rise in temperature during motor operation. Estimation errors degrade the control performance. Hence, this study proposes a simple stator resistance estimation method. In this scheme, the differential components of voltage and current values are used to eliminate the dead-time effect, and Kalman filter algorithm is applied to reduce the error according to measurement noise. Simulation and experimental results obtained with a permanent magnet motor show the validity of the proposed algorithm.

• Corrosion Science and Technology
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• v.21 no.6
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• pp.495-502
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• 2022

Anodization is a representative electrochemical surface treatment method that can improve both heat resistance and corrosion resistance by forming an anodization film on the surface of the aluminum. However, these properties can be changed after an additional heat treatment process. In this study, Al 6061 was subjected to an anodization process at 60 V for 1 hour, 5 hours, or 9 hours. An additional heat treatment process was performed at 500 ℃ for 30 minutes. Field emission scanning electron microscopy (FE-SEM) analysis revealed that the thickness of the anodized film was increased in proportion to the anodization time. Both pore size and pore diameter of the anodized film was also increased after anodization. After an additional heat treatment process, there were no significant changes in the thickness, pore size, or pore diameter of the anodized film. Heat resistance was confirmed through thermal analysis and chemical resistance was evaluated with a potentiodynamic polarization test.

• Journal of Chest Surgery
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• v.25 no.11
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• pp.1192-1202
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• 1992

Postoperative cardiac outputs and other hernoaynamic values were serially measured in fifteen patients of cyanotic congenital heart disease, after use of blood cardioplegic solution. Cardiac indices showed no change untill eight postoparative hours, then it began to decline to reach as low as 3.22$\pm$0.7L/min/m2 at 12 hours. After then gradual increse occ-ured to recover upto immediate postoperative value at 20 hours. Sharp decrese of heart rate and increse of systemic vascular resistance during 8~16 hours and steady increase of stroke indices during the whole study periods were observed. These observations suggested that the myocardium recovered gradually after open heart surgery, and that the decrease of cardiac indices during 8~16 hours could be a result of decrease of heart rates and increase of afterload. The changes of cardiac indices correlated with the changes of heart rate, postoperative time and mixed venous oxygen saturation [p<0.05]. No other hemodynamic values found to be in statistically significant correlation with the changes of cardiac indices. Left ventricular dysfunction seemed to occur more frequently during 8~12 hours, but it was not statistically significant. [p=0.73] In conclusion, great care must be taken during 2~3 days after the operation of cyanotic congenital heart disease, not to fall into a low cardiac output state, by maintaing adequate heart rates and reducing afterload especially when the systemic vascular resistance increases.