Mirror surface machining for large area flattening in the display field has a problem such as a tool wear and a increase in machining time due to large area machining. It should be studied to decrease machining time and tool wear. In this paper, multi-tool machining method using a PCD tool and a SCD tool was applied in order to decrease machining time and tool wear. Machining characteristics (cutting force, machined surface and surface roughness) of PCD tool and SCD tool were evaluated in order to apply PCD tool to flattening machining. Based on basic experi- ments, the PCD/SCD multi-tool method and the SCD single-tool method were compared through surface roughness and machining time for appllying large area mold machining.

Stearoyl-CoA desaturase (SCD1) gene plays important role in fatty acid composition. In order to find marker-assisted selection (MAS) for improving the economic trait, this study was performed to identify the 878T>C single nucleotide polymorphism (SNP) on SCD1 gene. Three genotypes (CC, CT, and TT) were detected in 878T>C SNP of SCD1 gene from 103 Hanwoo population by polymorphism chain reaction-restriction fragment length polymorphism (PCR-RFLP) and economic traits were analyzed by general linear model. The frequency of allele C and T was 0.534 and 0.466, also the genotype frequency of CC, CT and TT was 0.252, 0.563, and 0.184, respectively in the Hanwoo population. The TT genotype of SCD1 gene showed a significantly higher measures (p<0.05) of carcass weight (CW) than CT, CC genotype. No significant association was detected between genotype and other economic trait (marbling, backfat thickness, and longissimus muscle area) in this study. The results revealed that SCD1 gene 878T>C SNP could be useful for effective MAS to increase the economic quality in Hanwoo population.