Seeds of Dodonaea viscosa （L.） Jacq, a representative species in dry and hot valleys in Southwest China, were chosen as experimental materials. In this experiment, the D. viscosa seeds were treated at 40, 60, 80 and...Seeds of Dodonaea viscosa （L.） Jacq, a representative species in dry and hot valleys in Southwest China, were chosen as experimental materials. In this experiment, the D. viscosa seeds were treated at 40, 60, 80 and 100℃ respectively before germination to study impacts of high temperature treatment on their generation rate and to further discuss the roles of fire during the process of vegetation formation in dry and hot valley areas of China. The results show that when the temperature was higher than 40 ℃, the germination rate of D. viscosa seeds was significantly higher than that of the control group, and the heat shock effect was apparent. The germination rate was the highest when the seeds were treated at 80 ℃ for 10 min, reaching 63.00%±2.55%. There was still a significant heat shock effect on the D. viscosa seeds which were stored for one year. In comparison with the conventional method of soaking seeds in hot water, the germination rate of D. viscose seeds which were treated at high temperature before germination increased significantly.展开更多
An optical fiber pyrometer prototype has been developed for accurate measurement of overheating gas temperature.The optical fiber pyrometer and its technique could have the potential of measuring temperature up to 2 0...An optical fiber pyrometer prototype has been developed for accurate measurement of overheating gas temperature.The optical fiber pyrometer and its technique could have the potential of measuring temperature up to 2 000 ℃. The operation principle of the pyrometer is based on Planck's law and Stephen-Boltzmann's law. The test results are presented.展开更多
High temperature heat-treatment of wood, which is value-added green product, is one of the altematives to chemical treatment. It has better dimensional stability, thermal insulating properties and biological resistanc...High temperature heat-treatment of wood, which is value-added green product, is one of the altematives to chemical treatment. It has better dimensional stability, thermal insulating properties and biological resistance compared to kiln dried wood. It also has dark brown color which is very important for decorative purposes. Unfortunately, this color changes during weathering. Developing a transparent and non-toxic coating for the protection of heat-treated wood against discoloration without changing its natural appearance is the main objective of this study. For this purpose, waterborne acrylic polyurethane base was chosen because of its durability against weathering and non-toxic nature. Natural antioxidants which are extracted from barks and CeO2 nano particles （alone or together with lignin stabilizer） were used as additives to develop different coatings. The protective characteristics of these coatings were compared with highly pigmented and toxic industrial coating under accelerated weathering conditions. The results showed that acrylic polyurethane coatings protected wood better compared to commercially available coating tested in this study. The chemical modifications during accelerated weathering of coated and heat-treated wood surfaces were monitored by X-ray photoelectron spectroscopy analysis. The morphological changes took place during weathering were studied by fluorescence microscope analysis.展开更多
基金Supported by the National Water Pollution Control and Treatment Science and Technology Major Project(2012ZX07101-003-04-04)~~
文摘Seeds of Dodonaea viscosa （L.） Jacq, a representative species in dry and hot valleys in Southwest China, were chosen as experimental materials. In this experiment, the D. viscosa seeds were treated at 40, 60, 80 and 100℃ respectively before germination to study impacts of high temperature treatment on their generation rate and to further discuss the roles of fire during the process of vegetation formation in dry and hot valley areas of China. The results show that when the temperature was higher than 40 ℃, the germination rate of D. viscosa seeds was significantly higher than that of the control group, and the heat shock effect was apparent. The germination rate was the highest when the seeds were treated at 80 ℃ for 10 min, reaching 63.00%±2.55%. There was still a significant heat shock effect on the D. viscosa seeds which were stored for one year. In comparison with the conventional method of soaking seeds in hot water, the germination rate of D. viscose seeds which were treated at high temperature before germination increased significantly.
文摘An optical fiber pyrometer prototype has been developed for accurate measurement of overheating gas temperature.The optical fiber pyrometer and its technique could have the potential of measuring temperature up to 2 000 ℃. The operation principle of the pyrometer is based on Planck's law and Stephen-Boltzmann's law. The test results are presented.
文摘High temperature heat-treatment of wood, which is value-added green product, is one of the altematives to chemical treatment. It has better dimensional stability, thermal insulating properties and biological resistance compared to kiln dried wood. It also has dark brown color which is very important for decorative purposes. Unfortunately, this color changes during weathering. Developing a transparent and non-toxic coating for the protection of heat-treated wood against discoloration without changing its natural appearance is the main objective of this study. For this purpose, waterborne acrylic polyurethane base was chosen because of its durability against weathering and non-toxic nature. Natural antioxidants which are extracted from barks and CeO2 nano particles （alone or together with lignin stabilizer） were used as additives to develop different coatings. The protective characteristics of these coatings were compared with highly pigmented and toxic industrial coating under accelerated weathering conditions. The results showed that acrylic polyurethane coatings protected wood better compared to commercially available coating tested in this study. The chemical modifications during accelerated weathering of coated and heat-treated wood surfaces were monitored by X-ray photoelectron spectroscopy analysis. The morphological changes took place during weathering were studied by fluorescence microscope analysis.
