A novel dynamic excitation of an S-shaped PZT piezoelectric actuator, which is conceptualized by having two superimposed AC voltages, is characterized in this paper through the evaluation of the 2-D scanning characteristics of an integrated silicon micromirror. The device is micromachined from a SOI wafer with a 5 μm thick Si device layer and multilayers of Pt/Ti/PZT//Pt/Ti deposited as electrode and actuation materials. A large mirror (1.65 mm x 2mm) and an S-shaped PZT actuator are formed after the backside release process. Three modes of operation are investigated: bending, torsional and mixed. The resonant frequencies obtained for bending and torsional modes are 27Hz and 70Hz respectively. The maximum measured optical deflection angles obtained at 3Vpp are ± 38.9° and ± 2.1° respectively for bending and torsional modes. Various 2-D Lissajous patterns are demonstrated by superimposing two ac sinusoidal electrical signals of different frequencies (27 Hz and 70 Hz) into one signal to be used to actuate the mirror.
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http://dx.doi.org/10.1364/OE.19.013812 | DOI Listing |
JOR Spine
March 2025
Beijing Key Laboratory for Design and Evaluation Technology of Advanced Implantable & Interventional Medical Devices, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering Beihang University Beijing China.
Background: Growth rods are the gold standard for treating early-onset scoliosis (EOS). However, current treatments with growth rods do not optimize spinal growth in EOS patients, and frequent distraction surgeries significantly increase complications, imposing considerable economic and psychological burdens on patients. An improved growth rod is urgently required to address the need for dynamic growth and external regulation.
View Article and Find Full Text PDFJ Biomech
January 2025
Department of Mechanical Engineering & Mechanics, Lehigh University, 27 Memorial Drive West, Bethlehem, PA 18015, USA. Electronic address:
In large animal models of bone fracture repair, postmortem torsional testing is commonly used to assess healing biomechanics. Bending and axial tests are physiologically relevant, but much less commonly performed. Virtual torsional testing using image-based finite element models has been validated to postmortem bench tests, but its predictive value for capturing whole-bone mechanics and fracture healing quality under other physiologically relevant loading modes has not yet been established.
View Article and Find Full Text PDFFront Bioeng Biotechnol
December 2024
Bone and Joint Research Center, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan.
Background: Pediatric supracondylar humeral fractures present considerable surgical challenges due to the difficulty of achieving proper fracture alignment and stable fixation while avoiding injury to the ulnar nerve. This study assesses the biomechanical performance of a novel Kirschner wire (K-wire) fixation device (KFD), designed to enhance stability and reduce complications linked to traditional K-wire configurations.
Methods: Using finite element analysis (FEA), we evaluated four fixation strategies for treatment of pediatric supracondylar humeral simple transverse fractures: crossed pin fixation, crossed pin fixation with KFD, two lateral pin fixation, and two lateral pin fixation with KFD, under various mechanical loads.
J Hand Surg Glob Online
November 2024
The Curtis National Hand Center, MedStar Union Memorial Hospital, Baltimore, MD.
Purpose: Osteoporotic patients are at risk of peri-implant fractures after distal radius fixation. A unicortical screw in the proximal hole of the plate can theoretically decrease stress riser formation by eliminating the hole in the far bone cortex. This construct has been proposed in orthopedic literature to prevent peri-implant fractures but has not been tested in an osteoporotic distal radius model.
View Article and Find Full Text PDFBiomed Tech (Berl)
December 2024
Department of Trauma Surgery and Orthopedics, Clinical Centre Stuttgart-Katharinenhospital, Stuttgart, Germany.
Objectives: Helical plating is an established method for treating proximal humeral shaft fractures, mitigating the risk of iatrogenic radial nerve damage. However, biomechanical test data on helical plates under physiological load condition is limited. Hence, the aim of this study was to compare the biomechanical performance of helical and straight PHILOS Long plates in AO12C2 fractures using static and cyclic implant system testing.
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