Characterization of piezoelectrically actuated PLD Pb(Zr,Ti)O3 thin film membranes

In our previous work, we presented a novel technique for fabricating Transmission Electron Microscopy (TEM) chips in order to investigate structural and piezoelectric properties of Pulsed Laser Deposited (PLD) Lead Zirconium Titanate (Pb(Zr,Ti)O3) (PZT) thin films. We accomplished the fabrication of the devices we presented last year and obtained fully functional PLD PZT membranes. In this paper, we present the results of the fabrication process, which involves silicon-on-insulator (SOI) wafer technology together with deep reactive ion etching (DRIE) and highly selective etchants. In addition, we demonstrate the functionality of the membranes by piezoelectric actuation and characterized a selected membrane design through a set of experiments including X-ray diffraction (XRD), residual stress and frequency analyses

Towards in-situ tem analysis of PLD Pb(Zr,Ti)O3 thin film membranes

In this paper, a novel technique for fabricating Transmission Electron Microscopy (TEM) chips for investigating structural and piezoelectric properties of Pulse Laser Deposited (PLD) Lead Zirconium Titanate (PZT) thin films is presented. The method involves silicon-on-insulator (SOI) wafer technology together with deep reactive ion etching (DRIE) and highly selective etchants. This study is unique in the sense that it will facilitate in-situ characterization of the PLD PZT membranes during actuation. As well as PLD PZT, the proposed method can be applied to a variety of materials by proper selection of the etchants and tuning of the process parameters. Being a critical step of the process sequence, the deposition profile of the PZT layer on the Lanthanum Nickel Oxide (LNO) seed layer is characterized prior to fabrication. The results reveal that the PLD process is not conformal and the thickness of the LNO/PZT layer is different on surfaces with different topographies

Load on osseointegrated fixation of a transfemoral amputee during a fall: Loading, descent, impact and recovery analysis

Falling represents a health risk for lower limb amputees fitted with an osseointegrated fixation mainly because of the potential damage to the fixation. The purpose of this study was to characterise a real forward fall that occurred inadvertently to a transfemoral amputee fitted with an osseointegrated fixation while attending a gait measurement session to assess the load applied on the residuum. The objective was to analyse the load applied on the fixation with an emphasis on the sequence of events, the pattern and the magnitude of the forces and moments. The load was measured directly at 200 Hz using a six-channel transducer. Complementary video footage was also studied. The fall was divided into four phases: loading (240 ms), descent (620 ms), impact (365 ms) and recovery (2495 ms). The main impact forces and moments occurred 870 ms and 915 ms after the heel contact, and corresponded to 133 %BW and 17 %BWm, or 1.2 and 11.2 times the maximum forces and moments applied during the previous steps of the participant, respectively. This study provided key information to engineers and clinicians facing the challenge to design equipment, and rehabilitation and exercise programs to restore safely the locomotion of lower limb amputees