Thin film of biodegradable calcium phosphate coated on threaded commercially pure titanium （ cp- Ti ） dental implants has been investigated as one of alternatives to eliminate the problem of the long- term instabil...Thin film of biodegradable calcium phosphate coated on threaded commercially pure titanium （ cp- Ti ） dental implants has been investigated as one of alternatives to eliminate the problem of the long- term instability of plasma sprayed HA coated implants. In order to compare in-vivo bone-to-implant response behavior among as-machined, HA coated and CMP coated groups, each group was implanted into New Zealand white mature male rabbits for 2 and 6 weeks, and then in-vivo biological behavior was examined in terms of H＆E staining. Initial stability and removable torques of implants were compared among three groups. Measured removable torque of CMP coated specimen at 6 weeks after inplantation was significantly higher than that of non-coated group, but slightly lower than that of HA coated group, without any inflammatory response at the surrounding of the implants. The initial stability （ ISQ value ; implant stability quotient ） of CMP coated specimen at 2 weeks after implantation was slightly lower than that of HA coated group and significantly higher than that of non-coated group. However, after 6 weeks, ISQ value of CMP coated group was slightly higher than that of HA coated group and significantly higher than that of non-coated group.展开更多
We study the initial value problem of the Helmholtz equation with spatially variable wave number. We show that it can be stabilized by suppressing the evanescent waves. The stabilized Helmholtz equation can be solved ...We study the initial value problem of the Helmholtz equation with spatially variable wave number. We show that it can be stabilized by suppressing the evanescent waves. The stabilized Helmholtz equation can be solved numerically by a marching scheme combined with FFT. The resulting algorithm has complexity n^2 log n on a n x n grid. We demonstrate the efficacy of the method by numerical examples with caustics. For the Maxwell equation the same treatment is possible after reducing it to a second order system. We show how the method can be used for inverse problems arising in acoustic tomography and microwave imaging.展开更多
文摘Thin film of biodegradable calcium phosphate coated on threaded commercially pure titanium （ cp- Ti ） dental implants has been investigated as one of alternatives to eliminate the problem of the long- term instability of plasma sprayed HA coated implants. In order to compare in-vivo bone-to-implant response behavior among as-machined, HA coated and CMP coated groups, each group was implanted into New Zealand white mature male rabbits for 2 and 6 weeks, and then in-vivo biological behavior was examined in terms of H＆E staining. Initial stability and removable torques of implants were compared among three groups. Measured removable torque of CMP coated specimen at 6 weeks after inplantation was significantly higher than that of non-coated group, but slightly lower than that of HA coated group, without any inflammatory response at the surrounding of the implants. The initial stability （ ISQ value ; implant stability quotient ） of CMP coated specimen at 2 weeks after implantation was slightly lower than that of HA coated group and significantly higher than that of non-coated group. However, after 6 weeks, ISQ value of CMP coated group was slightly higher than that of HA coated group and significantly higher than that of non-coated group.
文摘We study the initial value problem of the Helmholtz equation with spatially variable wave number. We show that it can be stabilized by suppressing the evanescent waves. The stabilized Helmholtz equation can be solved numerically by a marching scheme combined with FFT. The resulting algorithm has complexity n^2 log n on a n x n grid. We demonstrate the efficacy of the method by numerical examples with caustics. For the Maxwell equation the same treatment is possible after reducing it to a second order system. We show how the method can be used for inverse problems arising in acoustic tomography and microwave imaging.
