• The Korean Journal of Ceramics
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• 제5권3호
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• pp.235-238
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• 1999

In a ceramic green body, some degree of nonuniformity in density always presents. These differences in green density will appear as nonuniform shrinkage after sintering takes place. For the complex ceramic bodies with various curves and angles, therefore, it is quite difficult to foresee the final dimensions precisely after sintering. This simulation study shows that, considering the sintering process as a thermal shrinkage phenomenon, the use of NASTRAN enables to predict the precise shape of a sintered body. Based on this result, 'the reverse engineering technique' has been developed that can unfold the exact dimensions of a green body to have the desired shape after sintering. This approach will provide a simple and useful tool for ceramic engineers to fabricate complicate bodies with tight dimensional tolerances.

• 생물정신의학
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• 제3권1호
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• pp.37-45
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• 1996

Recent studies on long-term outcome of schizophrenia revealed that schizophrenic symptoms recover in more than 50%, while it remains severe in less than 20% after 20 years or more from the onset. Psychopharmacological studies indicate that 75% of remitted schizophrenics may recur within 2 years after discontinuation of maintenance pharmacotherapy. In addition, family studies revealed that schizophrenic decompensation may occur significantly more frequent in discharged patients with high expressed emotion family than in low expressed emotion family. These findings strongly support a clinical validity of stress-vulnerability concept of schizophrenia which open a new viewpoint to two central problems in schizophrenia treatment, i.e. psychotic relapses and chronification of the fist episode schizophrenia. Moreover, recent psychopathological studies argue that schizophrenic symptoms are manifestations of psychological reaction secondary to a primary cognitive impairment(neurobiological vulnerability), which is originated in neurobiological changes in the brain. Recent approaches to the vulnerability to schizophrenic symptoms or schizophrenic decompensation are reviewed.

• Corrosion Science and Technology
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• 제23권3호
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• pp.228-234
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• 2024

Zinc wiping is a phenomenon used to control zinc-coating thickness on steel substrate during hot dip galvanizing by equipment called air knife. Uniformity of zinc coating weight in length and width profile along with surface quality are most critical quality parameters of galvanized steel. Deviation from tolerance level of coating thickness causes issues like overcoating (excess consumption of costly zinc) or undercoating leading to rejections due to non-compliance of customer requirement. Main contributor of deviation from target coating weight is dynamic change in air knives equipment setup when thickness, width, and type of substrate changes. Additionally, cold coating measurement gauge measure coating weight after solidification but are installed down the line from air knife resulting in delayed feedback. This study presents a coating weight control model (Galvantage) predicting critical air knife parameters air pressure, knife distance from strip and line speed for coating control. A reverse engineering approach is adopted to design a predictive, prescriptive, and descriptive model recommending air knife setups that estimate air knife distance and expected coating weight in real time. Implementation of this model eliminates feedback lag experienced due to location of coating gauge and achieving setup without trial-error by operator.