Extraction of biomedical compounds from the wood of Pterocarpus macarocarpus Kurz heartwood.
Some wood can be used as traditional Chinese medicine. The medicinal value of wood is associated with its extractives. Pterocarpus macarocarpus Kurz heartwood is a kind of top valuable reddish hardwood in making furniture and handicrafts, but the research about medicine value of this wood is not enough. In order to investigate the high value biomedical compounds in Pterocarpus macarocarpus Kurz heartwood, the woody extractives were obtained by Soxhlet extraction and ultrasonic extraction with benzene-ethanol (1:2, v/v) solvent simultaneously and were analyzed by Gas Chromatography-Mass Spectrometer (GC-MS). Combining with the results of the two extraction methods, 44 compounds can be identified in total. Amony these identified compounds, there were 5 flavonoids, 15 terpenes and 3 steroidal compounds. The representative biomedical compositions were homopterocarpin, medicarpin, (-)-pterocarpin, formononetin, β-eudesmol, stigmasterol, linoleic acid and so on, which indicated that the extractives from Pterocarpus macarocarpus Kurz heartwood have huge potential in biomedicine. This research provides scientific basis for further comprehensive utilization of Pterocarpus macarocarpus Kurz heartwood as Chinese medicine.
Effect of heat treatment and wax impregnation on dimensional stability of Pterocarpus macrocarpus wood.
In order to improve dimensional stability and control deformation, heat treatment (HT) and wax impregnation (WI) were conducted to large size boards (LB) of Pterocarpus macrocarpus and the tangential swelling were compared in various relative humidity (RH) conditions. The results show that the tangential swelling and shrinking of control group and treated group performed differently corresponded to various relative humidity (RH). Comparing with control group, the swelling ratio of HT combined WI group was much less, and followed by 180°C-3h HT group. The maximum swelling ratio decreased by 31% and 29% in humidity chamber and indoor conditions respectively. The swelling ratio was affected by size of samples, LB showed smaller welling ratio than small sample. Wax filled in cell cavities and presented uneven distributions after impregnation. The rate of wood hygroscopicity was reduced after HT combined WI treatment which was an effective method on improvement of wood dimensional stability.
Joint strength of aluminum ultrasonic soldered under liquidus temperature of Sn–Zn hypereutectic solder
Abstract In order to obtain high-strength aluminum joints, ultrasonic soldering of 1070 aluminum was conducted under liquidus temperature of Sn–Zn hypereutectic solder. A device for ultrasonic soldering was assembled, which propagated ultrasonic vibrations in a direction perpendicular to joining surfaces. This device joined 1070-Al using quasi-melting Sn–Zn hypereutectic solder without using any artificial spacers. The strength of the solder joints was evaluated by tensile tests. The optimum joining conditions were determined, and the effects of solder compositions and soldering temperature on the joint strength and the solder layer thickness were examined. In this ultrasonic soldering process, the highest tensile strength was obtained for the solder joints fabricated at 220 °C for the Sn–23Zn and Sn–40Zn solder compositions. The joint strength was equivalent to that of 1070-Al heat treated at 220 °C. The sound joints were obtained at 300 °C using Sn–82Zn solder, the liquid phase volume fraction of which was theoretically only 0.24. The present work also revealed that the thickness of retained solder layer in the joint after ultrasonic soldering could be estimated. Accordingly, ultrasonic soldering under the liquidus temperature of Sn–Zn hypereutectic solder could be a spacer-free soldering method to obtain high-strength aluminum joints.