• Journal of the Korean Society for Precision Engineering
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• v.4 no.4
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• pp.72-83
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• 1987

In axisymmetric tube reducing process for thin sheet metal tubes, the reduction ration of diameter is an important factor in the process design. For very thin sheet metal tubes, tube reducing cannot be successfully employed due to wrinkling of the edge portion of a tube as well as due to buckling of its rest portion. In the present study, thin sheet metal tubes are subjected to internal pressure during the tube reducing process in order to increase the forming limits. Analysis is made for the sound flow deformation in nonsteady tube reducing considering the normal anisotropy. Experiments are carried out for brass tubes. The present study is shown to give an effective guide line in designing the tube reducing process for very thin-walled sheet metal tubes. Hpwever, it is suggested that an analysis for instability should be made to design the process more effectively.

• Journal of Korean Society for Quality Management
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• v.27 no.2
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• pp.81-100
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• 1999

Process capability indexes are widely used in industries. Nevertheless, important statistical issues that deal with the appropriate use of process capability indexes have only appeared in the technical literature and are thus unknown to many users. In this paper we will first review various kinds of process capability indexes and then try to understand how much uncertainty is associated with them in relation to the assumption of normal distribution, the estimate of ${\sigma}$, the sampling error, the size of number of observations available and the presence of data correlation. Finally, we will propose a proper use of process capability indexes in an effort to assess a complex process.

• Proceedings of the Safety Management and Science Conference
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• 2005.05a
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• pp.503-521
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• 2005

Process capability indices are widely used in industries and quality assurance system. When designing the parameter on the multiple quality characteristics, there has been a study for optimization of problems, but there has been few former study on the possible conflicting phenomena in considertion of the correlations among the characteristics. To solve the issue on the optimal design for muliple quality characteristics, the study propose the expected loss function with cross-product terms among the characteristics and derived range of the coefficients of terms. Therefore, the analysis have to be required a multivariate statistical technique. This paper introduces to multivariate capability indices and then selects a multivariate process capability index incorporated both the process variation and the process deviation from target among these indices under the multivariate normal distribution. We propose a new multivariate capability index $MC_{pm}^{++}$ using quality loss function instead of the process variation and this index is compared with the proposed indices when quality characteristics are independent and dependent of each other,

• Proceedings of the Safety Management and Science Conference
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• 2004.11a
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• pp.69-79
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• 2004

Process capability indices are widely used in industries and quality assurance system. When designing the parameter on the multiple quality characteristics, there has been a study for optimization of problems, but there has been few former study on the possible conflicting phenomena in considertion of the correlations among the characteristics. To solve the issue on the optimal design for multiple quality characteristics, the study propose the expected loss function with cross-product terms among the characteristics and derived range of the coefficients of terms. Therefore, the analysis have to be required a multivariate statistical technique. This paper introduces to multivariate capability indices and then selects a multivariate process capability index incorporated both the process variation and the process deviation from target among these indices under the multivariate normal distribution. We propose a new multivariate capability index $MC_{pm}^{++}$ using quality loss function instead of the process variation and this index is compared with the proposed indices when quality characteristics are independent and dependent of each other.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.151-152
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• 2002

An oxidized surface layer was intentionally formed on a sputtered $MoS_2$ film by introducing oxygen gas in the final stage of sputtering process. The film showed longer life than the normal Ar-sputtered film when the surface layer was slightly oxidized. A XPS analysis revealed co-existence of $MoS_2$ and $MoO_3$ in the surface layer. suggesting that the existence of some amount of oxides in the surface layer had beneficial effect. A confusing result was obtained: the life was much shorter than normal Ar-sputtered film when the film was exposed to $O_2$ environment for 1 minute after normal Ar-sputtering, although almost no oxide was detected in XPS analysis.

• Journal of Korean Neurosurgical Society
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• v.30 no.6
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• pp.790-794
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• 2001

Spinal osteochondroms are very rare, and are thought to arise through a process of progressive endochondral ossification of aberrant cartilage of a growth plate, as a consequence of congenital defect or trauma. A case of diffuse type osteochondroma involving the posterior elements of L1-L5 that progressed after laminectomy in a 33-year-old man is reported. Usually, the spinal osteochondroma shows clear demarcation between tumor margin and normal spine elements, and can be exised completely. However, there was no clear demarcation between tumor and normal spine element in our case and therefore it was not possible to removal completely.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.585-590
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• 2001

Cracks in concrete can submit shear forces by virtue of the roughness of their interfaces. With regard to this roughness, the crack faces play an important role. By transmitting normal and shear stress across their faces, shear cracks contribute to shear resistance. This process is called shear transfer or more generally, shear friction. Both experimental and analytical program to investigate shear transfer mechanism in normal and high strength concrete were included in this study. The parameters investigated in push-off test included the concrete strength, the presence and amounts of steel stirrups, and aggregate size. Solution procedure based on the truss model was developed to analyze the shear transfer behavior. In general, it can be seen that the analytical results agree well with results of shear transfer test.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.10
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• pp.46-55
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• 1996

As industrial standard data, the STL format which approximates three dimensional CAD model to triangular facets, is used for RP(Rapid Prototyping) system in recent days. Because most RP system take the only form of two dimensional line segments as an input stream inspite of its imperfectness while converting into STL format, a CAD model is converted into a standard industrial format which is composed of many triangular facets. The error verifying process is composed of four main steps, and these are 1) Remove facets with two or more vertices equal to each other. 2) Fix overlapping error such as more than three facets adjacent to anedge. 3) Fill holes in the mesh by using Delaunay triangulation method. 4) Correct the wrong direction and normal vectors. This paper is concerned with serching the mentioned errors in advance and modifying them.

• Journal of Applied Biological Chemistry
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• v.57 no.1
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• pp.33-40
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• 2014

Polysaccharides have attracted great attention for their wide range of applications in biological and medical fields. In this paper, the interaction of polysaccharides with human serum albumin (HSA) was systematically investigated by fluorescence (FL) spectroscopy and circular dichroism (CD) spectra under different conditions. The Stern-Volmer quenching constants ($K_a$) at different ionic strength and pH were calculated, and information of the structural features of HSA was discussed. FL and CD results indicate that both hydrophobic and electrostatic interactions play important roles during the binding process. The quenching of the fluorescence resulting the binding of polysaccharides and HSA is static.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.5
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• pp.908-913
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• 1997

The purpose of this study was to investigate phospholipase $A_{2}$ activity and lipid peroxidation I streptozotocin induced diabetic rats. Sprague-Dawley male rats weighting-Dawley male rats weighting 300$\pm$10gm were randomly assigned to normal and STZ-induced diabetic group. Diabetes was induced by intravenous injection of 55mg/kg of STZ in sodium citrate buffer(pH 4.3). Animals were sacrificed at the 6th day of diabetic states. Body weight gains were lower in DM group. Phosphatidylcholine hydrolysis in liver was not significantly different between two groups, whereas phosphatidylethanolamine hydrolysis in liver was increased by 69% in DM group comparing with that of normal group. Liver microsomal phospholipase $A_{2}$ activity and level of TBARS was increased by 91%, 109% in DM group compared with that of normal group, respectively. The present results indicate that phospholipase $A_{2}$ activity is specific to PE hydrolysis, leading to lipid peroxidation process in STZ induced diabetic rats.