The investigation on the lightweight of automobiles has been underway in commercial vehicles as well as passenger cars due to global warming and strengthening of European emission standards. In this study, the V-arm were developed for lightweight parts using aluminum alloy instead of steel with high pressure die casting processing. This study has focused on lightweight adaptive concept design. Several models of V-arm were designed and analyzed for the fluidity and solidification. V-arm was produced with ADC12 by high pressure die-casting process. The mechanical properties of developed V-arm were measured; such as tensile strength, elongation, shear strength, and durability. The possibility of mass production with the light weight aluminum V-arm substitute from the steel. The weight was reduced about 38% from 16kg to 9.98kg. The productivity was improved with decreasing the process from 8 to 5 by All-in-0ne process using high pressure die-casting.

Magnesium alloy is becoming known for the lightest material in the metallic materials. Recently the automotive industry has a variety application to the light weight parts replacement. This study focuses on the mechanical property improving through a tiny amount’s CNT addition into the magnesium alloy as AM60. The CNT material is an arduous combination of the metallic materials. Therefore this study is concentrating on the contact force growth for the CNT material. Consequently, the made CNT is produced by the CVD process using the magnesium catalyst. The CNT material has dispersive with mechanical process into the molten AM60 alloy. The mechanical experiment result that hardness is 18% increasing and tensile strength is 13% increasing, better than the raw AM60 alloy on this investigation.

The objective of this study was to examine the effect of EGF on meiotic maturation and pronuclear (PN) formation of porcine oocytes. Prepubertal gilt cumulus-oocyte-complexes (COCs) aspirated from 2~6mm follicles of abbatoir ovaries were matured in TCM199 containing 0.1mg/ml cysteine, 0.5㎍/ml FSH and LH, and EGF (0, 5, 10, 20, 40 ng/ml) for 22 hr at 39℃ in a humidified atmosphere of 5% CO2 in air. They were then cultured for an additional 22hr without hormones. In Experiment 1, to examine the nuclear maturation at 44hr of culture, the expanded cumulus cells were removed by vortexing for 1 min in 3 mg/ml hyaluronidase. The oocytes were fixed in acetic acid: methanol (1:3, v/v) at least for 48 hr and stained with 1% orcein solution for 5 min. Nuclear status was classified as germinal vesicle (GV), germinal vesicle breakdown (GVBD), prophase-metaphase I (PI-MI), and PII-MII under microscope. In Experiment 2, to investigate PN formation, oocytes were fertilized with Percoll-treated freshly ejaculated sperm (1 x10 5 cells/ml) in mTBM with 0.3% BSA and 2mM caffeine for 5hr, and cultured in NCSU-23 medium with 0.4% BSA. At 6hr of culture, the embryos were fixed in 3.7% formaldehyde for 48hr and stained with 10ug/ml propidium iodide for 30 min. PN status was classified as no or one PN (unfertilized), 2 PN (normal fertilized) and ≥3 PN (polyspermy). Differences between groups were analyzed using one-way ANOVA after arc-sine transformation of the proportional data. The rate of oocytes that had reached to PII-MII were significantly (P<0.05) higher in all groups added EGF than that of non-treated group (67%), but it did not differ among the all added groups (86%, 85%, 79% and 81%, in 5, 10, 20 and 40 ng/ml EGF, respectively). No differences on the incidence of 2PN were observed in all treated groups (25%, 30%, 33%, 29% and 29%, in 0, 5, 10, 20 and 40 ng/ml EGF, respectively), however, in non-treated group, polyspermy tended to be increased (66% vs 58%, 54%, 52% and 55%, 0 vs. 5, 10, 20, 40 ng/ml EGF, respectively). These results suggest that EGF can be effectively used as an additive for enhancing oocyte maturation and reducing the incidence of polyspermy in pig.