High-energy mechanical milling (HEMM) and sintering into Al-Mg alloy melt were employed tofabricate an Al alloy matrix composite reinforced with submicron and micron sized Al2O3 particles. Al-basedmetal matrix composite (MMC) reinforced with submicron and micron sized Al2O3 particles was successfullyfabricated by sintering at 1000oC for 2h into Al-Mg alloy melt, which used high energy mechanical milled Al-SiO2-CuO-ZnO composite powders. Submicron/micron-sized Al2O3 particles and eutectic Si were formed by in situdisplacement reaction between Al, SiO2, CuO, and ZnO during sintering for 2h into Al-Mg alloy melt and werehomogeneously distributed in the Al-Si-(Zn, Cu) matrix. The refined grains and homogeneously distributedsubmicron/micron-sized Al2O3 particles had good interfacial adhesive, which gives good wear resistance withhigher hardness.

Al-42wt%Nb powder was prepared by high-energy mechanical milling(HEMM). The particle size, phase transformation and microstructure of the as-milled powder were investigated by particle size distribution (PSD) analyzer, scanning electron microscopy (SEM), X-ray diffractometery (XRD), transmission electron microscopy (TEM)and differential thermal analysis (DTA). The milled powders were heated to a sintering temperature at 1000C with under vaccum with vaccum tube furnace. Microstructural examination of sintered Ti-42wt%Nb alloy using 4h-milled powder showed Ti-rich phases (α-Ti) which are fine and homogeneously distributed in the matrix (Nb-rich phase: β-Ti). The sintered Ti-42wt%Nb alloy with milled powder showed higher hardness. The microstructure of the as quenched specimens fabricated by sintering using mixed and milled powder almost are same, but the hardness of as quenched specimen fabricated by using mixed powder increased due to solution hardening of Nb in Ti matrix. The aging effect of these specimens on microstructural change and hardening is not prominent.

본 실험은 장기간의 알코올 섭취가 수종의 무기질 함량에 미치는 영향을 알아보고자 랫트를 공시하여 4% 및 25% 알코올을 28일간 자유 섭취시킨 후 간, 신장, 근육 및 피모내의 Zn, Ca, Cu 및 Mg의 함량을 원자흡광분광광도법으로 측정하여 보았다. 실험결과를 요약하면 다음과 같다. 1. Zn 함량은 25% 투여군의 근육에서만 유의한 (P<0.01) 감소를 나타내었으며 피모에 있어서는 4% 투여군에서 유의한(p<0.10) 증가를 나타내었다. 2. Ca 함량은 4% 및 25% 투여군의 간, 신장 및 근육에서 유의한 차이가 인정되지 않았으나 4% 투여군의 피모에서는 유의한(p<0.10) 증가를 나타내었다. 3. Cu 함량은 4% 및 25% 투여군의 근육에서만 유의한(P<0.05) 감소를 나타내었다. 4. Mg 함량은 4% 및 25% 투여군의 근육에서만 유의한(P<0.10, P<0.05) 감소를 나타내었다.