Two new xanthons from Garcinia rigida leaves
Two new xanthons, musaxanthone (1) and asmaxanthone (2) were isolated from the leaves of Garcinia rigida. The structures were determined by means of spectroscopic analysis.
Triterpenoids from Garcinia rigida
The leaves of Garcinia rigida afforded six triterpenoid compounds, friedelin (1), lanosta-8,25-en-3 beta-ol (2), stigmasterol (3), lupeol (4), 3 beta-hydroxy-20(29)-en-lupan-30-al (5) and 3 beta-hydroxy-20(29)-en-lupan-30-ol (6). The structures of 1-6 were elucidated by IR, MS, NMR spectroscopies and comparison of their spectroscopic data with those reported in the literatures. Compound 6 showed toxicity to Artemia salina in brine shrimp lethality test (BLST) with LC(50) 27.72 mu g/mL.
Finite Difference Modeling on the Temperature Field of Substrate in Friction Surfacing
Friction surfacing is an advanced process of great potential, especially in the field of repair and reclamation of worn and damaged components. As a kind of thermal processing technology, the temperature profile and changes of the substrate in friction surfacing are important factors to get coatings of high quality. In this paper, the temperature field of the substrate during the process is simulated by finite difference method. The results are consistent with experiments, reappearing the temperature change of the substrate during friction surfacing, allowing further study on figuration and quality of coatings.