In this study, Al-Si-Mg alloys are additively manufactured using a selective laser melting (SLM) process from AlSi10Mg powders prepared from a gas-atomization process. The processing parameters such as laser scan speed and laser power are investigated for 3D printing of Al-Si-Mg alloys. The laser scan speeds vary from 100 to 2000 mm/ s at the laser power of 180 and 270W, respectively, to achieve optimized densification of the Al-Si-Mg alloy. It is observed that the relative density of the Al-Si-Mg alloy reaches a peak value of 99% at 1600 mm/s for 180W and at 2000 mm/s for 270W. The surface morphologies of the both Al-Si-Mg alloy samples at these conditions show significantly reduced porosities compared to those of other samples. The increase in hardness of as-built Al-Si-Mg alloy with increasing scan speed and laser power is analyzed due to high relative density. Furthermore, it was found that cooling conditions after the heat-treatment for homogenization results in the change of dispersion status of Si phases in the Al-Si matrix but also affects tensile behaviors of Al-Si-Mg alloys. These results indicate that combination between SLM processing parameters and post-heat treatment should be considered a key factor to achieve optimized Al-Si alloy performance.

This study was conducted to investigate the immuno-regulatory effect and apoptosis of L1210 and HL60 leukemia cells of methanol-extracts of Cornus kousa Burg(CKB). The proliferation of mouse splenocytes and thymocytes enhanced by the addition of 10 μg/ml of CKB. CKB were administered p.o. once a day for 7 days in adult male BALB/c mice. CKB increased the splenic and thymic T lymphocytes, especially the number of TH cells markedly increased by the treatment of CKB. CKB treatment induced the apoptotic cell death in L1210 mouse leukemia and HL60 human leukemia cells. In addition, CKB also accelerated the phagocytic activity in peritoneal macrophages and increased the production of plaque forming cells. These results suggest that CKB have an various immuno-regulatory property.