An antifogging function surface with simple structure and suitable for large-area production was found inspired by Ephemera pictiventris McLachlan compound eyes.The compound eyes structure,antifogging properties and mechanism were studied by anti-fog test,dyeing test and scanning electron microscopy,and so forth.Then,3D model of the sample was established,and the antifogging mechanism was explained by the Cassie model.Results showed that the compound eyes are composed of hundreds of micron size ommatidia arranged in curved array form,and this structure shows excellent antifogging function.This research may provide new ideas for design of simple structure and micron size antifogging function surface.This work is also expected to be applied to antifogging function surface of astronaut helmets and medical endoscopes,and so forth.
Most previous cervical spine finite element(FE) models were validated using in vitro cadaver measurement data from literatures. Although in vitro measurement can provide valuable data for model verification,the in vivo mechanical and physiological conditions of the cervical spine during its natural motions cannot be reproduced in vitro. In this study, a human FE model of skull(C0) and spinal vertebrae(C1–T1) was developed. The in vivo kinematic characteristics of head and neck were obtained from optoelectronic system, and used for the validation of the FE model. The simulation results showed good agreement with the measured data in left/right lateral bending and left/right axial rotation, while discrepancy existed during flexion. The predicted segmental cervical vertebral angles were compared against data from previous in vivo experiment, too. Furthermore, the skin shift data from previous study was used to compensate the experimental measurement during flexion and left/right lateral bending. The results showed the model was successfully validated with the in vivo experimental data.
