A cascade glow discharge in atmospheric helium was excited by a microsecond voltage pulse and a pulse-modulated radio frequency(RF) voltage, in which the discharge ignition dynamics of the RF discharge burst was inves...A cascade glow discharge in atmospheric helium was excited by a microsecond voltage pulse and a pulse-modulated radio frequency(RF) voltage, in which the discharge ignition dynamics of the RF discharge burst was investigated experimentally. The spatio-temporal evolution of the discharge, the ignition time and optical emission intensities of plasma species of the RF discharge burst were investigated under different time intervals between the pulsed voltage and RF voltage in the experiment. The results show that by increasing the time interval between the pulsed discharge and RF discharge burst from 5 μs to 20 μs, the ignition time of the RF discharge burst is increased from 1.6 μs to 2.0 μs, and the discharge spatial profile of RF discharge in the ignition phase changes from a double-hump shape to a bell-shape. The light emission intensity at 706 nm and 777 nm at different time intervals indicates that the RF discharge burst ignition of the depends on the number of residual plasma species generated in the pulsed discharges.展开更多
‘Bronze teeth＇ reflect the mechanical properties of natural teeth to a certain extent. Their mechanical properties resemble those of a tough metal, and the gradient of these properties lies in the direction from out...‘Bronze teeth＇ reflect the mechanical properties of natural teeth to a certain extent. Their mechanical properties resemble those of a tough metal, and the gradient of these properties lies in the direction from outside to inside. These attributes confer human teeth with effective mastication ability. Understanding the various mechanical properties of human teeth and dental materials is the basis for the development of restorative materials. In this study, the elastic properties, dynamic mechanical properties （visco-elasticity） and fracture mechanical properties of enamel and dentin were reviewed to provide a more thorough understanding of the mechanical properties of human teeth.展开更多
Micromotion and fretting damages at the dental implant/bone interface are neglected for the limitation of check methods, but it is particularly important for the initial success of osseointegration and the life time o...Micromotion and fretting damages at the dental implant/bone interface are neglected for the limitation of check methods, but it is particularly important for the initial success of osseointegration and the life time of dental implant. This review article describes the scientific documentation of micromotion and fretting damages on the dental implant/bone interface. The fretting amplitude is less than 30 l^m in vitroand the damage in the interface is acceptable. While in vivo, the micromotion＇s effect is the combination of damage in tissue level and the real biological reaction.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 11875104 and 12175036)。
文摘A cascade glow discharge in atmospheric helium was excited by a microsecond voltage pulse and a pulse-modulated radio frequency(RF) voltage, in which the discharge ignition dynamics of the RF discharge burst was investigated experimentally. The spatio-temporal evolution of the discharge, the ignition time and optical emission intensities of plasma species of the RF discharge burst were investigated under different time intervals between the pulsed voltage and RF voltage in the experiment. The results show that by increasing the time interval between the pulsed discharge and RF discharge burst from 5 μs to 20 μs, the ignition time of the RF discharge burst is increased from 1.6 μs to 2.0 μs, and the discharge spatial profile of RF discharge in the ignition phase changes from a double-hump shape to a bell-shape. The light emission intensity at 706 nm and 777 nm at different time intervals indicates that the RF discharge burst ignition of the depends on the number of residual plasma species generated in the pulsed discharges.
基金support from the National Natural Science Foundation of China(Nos.81170996,81070867 and 81100777)the Sichuan Province Science and Technology Innovation Team Program(2011JTD0006)
文摘‘Bronze teeth＇ reflect the mechanical properties of natural teeth to a certain extent. Their mechanical properties resemble those of a tough metal, and the gradient of these properties lies in the direction from outside to inside. These attributes confer human teeth with effective mastication ability. Understanding the various mechanical properties of human teeth and dental materials is the basis for the development of restorative materials. In this study, the elastic properties, dynamic mechanical properties （visco-elasticity） and fracture mechanical properties of enamel and dentin were reviewed to provide a more thorough understanding of the mechanical properties of human teeth.
基金the support of the National Natural Science Foundation of China (Nos. 81170996, 81070867, and 81100777)Sichuan Province Science and Technology Innovation Team Program (2011JTD0006)
文摘Micromotion and fretting damages at the dental implant/bone interface are neglected for the limitation of check methods, but it is particularly important for the initial success of osseointegration and the life time of dental implant. This review article describes the scientific documentation of micromotion and fretting damages on the dental implant/bone interface. The fretting amplitude is less than 30 l^m in vitroand the damage in the interface is acceptable. While in vivo, the micromotion＇s effect is the combination of damage in tissue level and the real biological reaction.
