Two-way shape memory effect (TWSME) was induced into the TiNi shape memoryalloys (SMAs) spring by thermomechanical training after annealing treatment, which has promisingapplication in micro-actuating fields. The TWSM...Two-way shape memory effect (TWSME) was induced into the TiNi shape memoryalloys (SMAs) spring by thermomechanical training after annealing treatment, which has promisingapplication in micro-actuating fields. The TWSME spring can contract upon heating and extend uponcooling. The results show that there is an increase of the recovery ratio up to a maximum TWSME of45%. During the training procedure, transformation temperatures and hysteresis were measured bydifferent scanning calorimetry (DSC). The results show that A_s (reverse transformation starttemperature) and A_f (reverse transformation finish temperature) shift to lower temperature aftertraining. The intervals of A_fA_s and M_s-M_f (M_s and M_f are the martensite start and finishtemperatures, respectively) increase and the heat of transformation decreases after training. Theelectrothermal driving characteristics of the TWSME springs were also investigated with alternatingcurrent density of 3.2-14.7 A/mm^2. It is found that the time response and the maximum contractionratio greatly depend on the magnitude of the electrical current density.展开更多
In the current research,the use of a micromachined cantilever resonator as a platform for chemical gas sensing was examined.The microcantilever resonator integrates an electrothermal driving unit and a piezoresistive ...In the current research,the use of a micromachined cantilever resonator as a platform for chemical gas sensing was examined.The microcantilever resonator integrates an electrothermal driving unit and a piezoresistive detecting unit,and it is fabricated by direct bonding a silicon-on-insulator（SOI） wafer.With a particular polymer layer coated on the surface of the microcantilever,a gas sensor for volatile organic components（VOCs） detection can be realized.The operation mechanism provides the microcantilever resonator with integrated circuit（IC） compatibility in terms of both the fabrication process and operating voltage.The configuration of the microcantilever resonator can optimize the performance of the gas sensor.The SOI wafer provides a solution for the integrated fabrication of the microstructure,transducers,electronics,and the precise control of the resonator parameters.In this paper,the principles,design,analysis,process,and demonstration of the gas sensor based on the microcantilever resonator are presented.The experimental results provide confirmation that the polymer-coated microcantilever resonator has excellent performance with regard to VOC detection.展开更多
基金This project is financially supported by the National Natural Science Foundation of China (No. 10175042)
文摘Two-way shape memory effect (TWSME) was induced into the TiNi shape memoryalloys (SMAs) spring by thermomechanical training after annealing treatment, which has promisingapplication in micro-actuating fields. The TWSME spring can contract upon heating and extend uponcooling. The results show that there is an increase of the recovery ratio up to a maximum TWSME of45%. During the training procedure, transformation temperatures and hysteresis were measured bydifferent scanning calorimetry (DSC). The results show that A_s (reverse transformation starttemperature) and A_f (reverse transformation finish temperature) shift to lower temperature aftertraining. The intervals of A_fA_s and M_s-M_f (M_s and M_f are the martensite start and finishtemperatures, respectively) increase and the heat of transformation decreases after training. Theelectrothermal driving characteristics of the TWSME springs were also investigated with alternatingcurrent density of 3.2-14.7 A/mm^2. It is found that the time response and the maximum contractionratio greatly depend on the magnitude of the electrical current density.
基金Supported by the National Natural Science Foundation of China (No 50605040)
文摘In the current research,the use of a micromachined cantilever resonator as a platform for chemical gas sensing was examined.The microcantilever resonator integrates an electrothermal driving unit and a piezoresistive detecting unit,and it is fabricated by direct bonding a silicon-on-insulator（SOI） wafer.With a particular polymer layer coated on the surface of the microcantilever,a gas sensor for volatile organic components（VOCs） detection can be realized.The operation mechanism provides the microcantilever resonator with integrated circuit（IC） compatibility in terms of both the fabrication process and operating voltage.The configuration of the microcantilever resonator can optimize the performance of the gas sensor.The SOI wafer provides a solution for the integrated fabrication of the microstructure,transducers,electronics,and the precise control of the resonator parameters.In this paper,the principles,design,analysis,process,and demonstration of the gas sensor based on the microcantilever resonator are presented.The experimental results provide confirmation that the polymer-coated microcantilever resonator has excellent performance with regard to VOC detection.
