• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.924-927
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• 2007

In this study, adaptation of two-way shape memory effect of SMA wire to the actuator is examined. Therefore the SMA characteristics which are training, material properties, response time at different thermal cycling rates are tested. During training, permanent deformation is accumulated till a certain number of cycle and then saturated. The amount of two-way strain is unchangeable over all cycle and the slope of strain(or stress)-temperature curve is slower as the increase of applied stress. The rate effect is observed resulted from the thermal distribution which heating profile differs from cooling as thermal cycling time. Using the estimated SMA properties, an experimental test for the simple smart wing is performed.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.10a
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• pp.53-56
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• 1996

The conventional inventory models are concerned with the items of which utilities and amount of numbers are constant over time. But in practice the items in inventory systems are increasing or decreasing. This study is concerned with the development of ameliorating inventory models. The ameliorating inventory is the inventory of goods whose utility increases over the time by ameliorating activation. The term ameliorating inventory is used in this paper at least, since the terminology is not standard well known. This study is performed according to areas; one is an economic order quantity(EOQ) model for the items whose utility is ameliorating in accordance with Weibull distribution, and the other is a partial selling quantity(PSQ) model developed for selling surplus inventory accumulated by ameliorating activation. Computer programs are developed to obtain the optimal ordering and selling quantity. Numerical examples to illustrate the effect of ameliorating rate on inventory polices are shown at the end of this paper.

• The Journal of the Korean Society for Microbiology
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• v.9 no.1
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• pp.41-45
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• 1974

On day 2 after treatment of Lewis rat with 25mg of hydrocortisone, the cell number in the thymus was reduced to less than 10% of the matched control. By day 12 after hydrocortisone treatment the thymic cell population was recovered almost its original value and on day 24 after treatment the number of thymocytes was equivalent to that of normal thymocytes. The density distribution profile of hydrocortisone treated rats as compared with normal rats showed a marked decrease in the denser fraction D while the lighter fractions. (A plus B, and C) showed a considerable proportional increase. The proportion of dead cells in thymus suspension from hydrocortisone treated rats was higher than that from their normal counterparts. On separation, the dead cells accumulated selectively in the pellet and A fraction. The response of the thymocytes from hydrocortisone treated rats to PHA was increased compared to that from normal rats. Among the subpopulations, D fraction, which was relatively unresponsive in normal rats, showed a marked increase in PHA response and C fraction showed some increase in the response.

• Proceedings of the Korean Quaternary Association Conference
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• 2005.06a
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• pp.7-11
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• 2005

The soil erosion processes have estimated using spatial distribution of 137Cs radionuclide in Granite and Sedimentary Hillslopes in South Korea. The local variability of 137Cs inventory indicates that was related positively to organic matter content, clay content and water content and negatively to hydraulic permeability and slope gradient for bulk samples in different landforms within Granite and Sedimentary rock basins. The vertical variability of 137Cs inventory shows that most of 137Cs concentration and organic matter were accumulated between 0 and 2cms and gradually decrease with soil depth in incremental samples in both basins. The vertical variability of 137Cs inventories shows that 137Csinventories increase as we go to toward downslope in both basins. Finally, the soil loss values indicate that hillslope erosion processes are more intensive in Granite rock basin than those in Sedimentary rock basin.

• Nuclear Engineering and Technology
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• v.30 no.1
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• pp.17-25
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• 1998

Transport of carbon and boron impurity ions parallel to magnetic field lines in the tokamak SOL (scrape-off layer) is numerically investigated for a one-dimensional steady state. The spatial distributions of density and velocity of the impurity ions in a steady state are calculated by finite difference method for a single-fluid model. The calculated results show that among forces acting on SOL particles thermal force produced tv plasma temperature gradient is a principal force determining the feature of impurity distribution profiles in the tokamak edge. However, strong collisional friction forces appearing dominant in front of the diverter plate restrain impurity ion flows due to temperature gradients from moving toward the midplane. Consequently, the stagnation point develops in the impurity flow by these two forces near the diverter region, in which ion flows change their directions. Impurity ions turn out to be accumulated at the stagnation points, where peaked profiles of highly-ionized state ions are relatively predominant over those of low-ionized state ions.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.11a
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• pp.145-148
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• 2005

In this study, adaptation of two-way shape memory effect of SMA wire to the actuator is examined . Therefore the SMA characteristics which are training, material properties, response time at different thermal cycling rates are tested. During training, permanent deformation is accumulated till a certain number of cycle and then saturated. The amow1t of two-way strain is unchangeable over all cycle and the slope of strain(or stress)-temperature curve is slower as the increase of applied stress. The rate effect is observed resulted from the thermal distribution which heating profile differs from cooling as thermal cycling time. Using the estimated SMA properties, an experimental test for the simple smart wing is performed.

• Toxicological Research
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• v.7 no.1
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• pp.37-46
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• 1991

To evaluate the influence of ochratoxin A on the pharmarcokinetics of gentamicin, gentamicin concentrations in the serum, renal cortex and medulla together with parameters of the renal function and histological changes were compared between ochratoxin A-treated rats (0.1 mg of ochratoxin A/kg of body weight, ip, daily for 14 days) and normal rats. Gentamicin was given with a single intramuscular injection (10mg/kg of body weight). Ochratoxin A resulted in an increase of the half-life, the area under the concentration-time curve, the apparent volume of distribution and a decrease of the total body clearance of gentamicin, and accumulated significantly (p<0.01) more gentamicin in the kidneys.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.392-394
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• 1995

The interfacial charge distribution was investigated using PE laminate system. It was found that a proper treatment of the interlace could decrease the amount of charge accumulated at the interfaces. High lamination temperature and long lamination time brought about little interfacial charge. It was also observed that the interfacial charge could be decreased by the addition of chemicals which had charge trap or hopping site.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2305-2306
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• 2008

Charging of spacecraft occurs in plasma and radiation environment. Especially, we focused on an accident caused by internal charging in a glass material that was used as the cover plate of solar panel array, and tried to measure the charge distribution in glass materials under electron beam irradiation by using a PEA (Pulsed Electro-Acoustic method) system. In the case of a quartz glass (pure $SiO_2$), no charge accumulation was observed either during or after the electron beam irradiation. On the contrary, positive charge accumulation was observed in glass samples containing metal-oxide components. It is found that the polarity of the observed charges depends on the contents of the impurities. To identify which impurity dominates the polarity of the accumulated charge, we measured charge distributions in several glass materials containing various metal-oxide components and calculated the trap energy depths from the charge decay characteristics of all glass samples.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.444-447
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• 2003

All objects with some temperature above absolute zero radiate in the infrared. The intensity of the infrared radiated from a object defends on the condition and temperature on the surface of the one. The present, these techniques are frequently adopted into diagnosis for electricity equipments. Simply, however, the applied techniques are passive thermal testing for the detection of loosened terminals and overcurrent. In this paper, a infrared thermal imager was applied to high voltage windings of cast resin transformers, and the accumulated value of the result temperatures was used for evaluating remained lifetime of them. At each aging level, dielectric loss tangent test was carried out. The results offered capabilities for deciding the condition of the transformers suffering difficulties to diagnose.