A recently emerging family of smart materials,photostrictive materials,exhibit large photostriction under uniform illumination of high-energy light.This photostriction mechanism arises from a superposition phenomenon ...A recently emerging family of smart materials,photostrictive materials,exhibit large photostriction under uniform illumination of high-energy light.This photostriction mechanism arises from a superposition phenomenon of photovoltaic and converse piezoelectric effects.A photostrictive type of opto-electromechanical actuator activated by high-energy lights can introduce actuation and control effects without hard-wired connections.The control light intensity applied to the actuator is proportional to the transverse velocity at a positioned point,which is measured by a laser vibrometer.In this paper,photostrictive films are numerically analyzed to evaluate their use as wireless actuators for future remote vibration control of flexible structures.A novel opto-electromechanical solid shell finite element formulation is developed for accurate analysis of the multiple physics effects of photovoltaic,pyroelectric and thermal expansion of photostrictive materials.Available experimental data and analytical solutions have been used to verify the present finite element results.The simulation in this study demonstrates that the present formulation is very reliable,accurate and also computationally efficient and that the use of photostrictive actuators can provide good controllability of structural vibration.展开更多
Three types of a-C:Co/Si samples were fabricated using the pulsed laser deposition: Co2-C98/8i with Co dispersed in the a-C film, Co2-C98/Si with Co segregated at the interface, and a-C/Co/Si with Co continuously dist...Three types of a-C:Co/Si samples were fabricated using the pulsed laser deposition: Co2-C98/8i with Co dispersed in the a-C film, Co2-C98/Si with Co segregated at the interface, and a-C/Co/Si with Co continuously distributed at the a-C/Si interface. Both types of Co2-C98/Si samples had the positive bias-voltage-dependent magnetoresistance (MR) at 300 K, and all MRs had saturated behavior. The study on the electrotransport properties indicated that the MR appeared in the diffusion current region, and the mechanism of MR was proposed to be that the applied magnetic field and local random magnetic field caused by the superparamagnetic Co particles modulate the ratio of singlet and triplet spin states, resulting in the MR effect. In addition, the very different physical and structural properties of all samples revealed that Co played a crucial role in the room-temperature positive MR of a-C:Co/Si system.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 10872090, 50830201)NUAA Research Funding (Grant No. NJ2010011)
文摘A recently emerging family of smart materials,photostrictive materials,exhibit large photostriction under uniform illumination of high-energy light.This photostriction mechanism arises from a superposition phenomenon of photovoltaic and converse piezoelectric effects.A photostrictive type of opto-electromechanical actuator activated by high-energy lights can introduce actuation and control effects without hard-wired connections.The control light intensity applied to the actuator is proportional to the transverse velocity at a positioned point,which is measured by a laser vibrometer.In this paper,photostrictive films are numerically analyzed to evaluate their use as wireless actuators for future remote vibration control of flexible structures.A novel opto-electromechanical solid shell finite element formulation is developed for accurate analysis of the multiple physics effects of photovoltaic,pyroelectric and thermal expansion of photostrictive materials.Available experimental data and analytical solutions have been used to verify the present finite element results.The simulation in this study demonstrates that the present formulation is very reliable,accurate and also computationally efficient and that the use of photostrictive actuators can provide good controllability of structural vibration.
基金support given by the National Natural Science Foundation of China (Grant Nos. U0734001 and 50772054)the Ministry of Science and Technology of China (Grant Nos. 2008CB617601 and 2009CB929202)
文摘Three types of a-C:Co/Si samples were fabricated using the pulsed laser deposition: Co2-C98/8i with Co dispersed in the a-C film, Co2-C98/Si with Co segregated at the interface, and a-C/Co/Si with Co continuously distributed at the a-C/Si interface. Both types of Co2-C98/Si samples had the positive bias-voltage-dependent magnetoresistance (MR) at 300 K, and all MRs had saturated behavior. The study on the electrotransport properties indicated that the MR appeared in the diffusion current region, and the mechanism of MR was proposed to be that the applied magnetic field and local random magnetic field caused by the superparamagnetic Co particles modulate the ratio of singlet and triplet spin states, resulting in the MR effect. In addition, the very different physical and structural properties of all samples revealed that Co played a crucial role in the room-temperature positive MR of a-C:Co/Si system.
