Rigid suckers commonly used in surgical procedures often cause absorption damage, while their soft counterparts are difficult to handle due to their weak anchoring. Alternatively, the octopus sucker is both soft and has strong suction power. Further observation revealed that its structure is self-sealing and that the tissues are layered in hardness. Inspired by said structure and the characteristics of associated materials, a bionic soft sucker with stiffness gradient and acetabular roof structure was proposed, made of silicone with varying hardness including structures such as acetabular roof and circle muscles. The automatic tensile force measurement system was used to experimentally analyze the adsorption performance of the suckers to the soft curved contact surface. Both dry and wet conditions were tested, along with practical tests on organisms. The bionic sucker adsorption force was increased by 25.1%and 34.6% on the cylindrical surface, and 45.2% and 7.3% on the spherical surface for dry and wet conditions, respectively. During the experiment, the bionic suckers did not cause notable suction damage to the contact surfaces. Thus, this type of bionic sucker shows good application prospects in the field of surgery.

The signal fading in wireless underground sensor networks (WUSNs), which is caused by lossy media such as soil and sand, can be reduced by applying technology of magnetoinductive (MI) propagation. This technology can effectively establish a communication at very low frequency (VLF). In contrast to the previous studies in the literature, which mostly focus on the propagation of plane waves, we propose a new approach based on the plane wave expansion (PWE) to model the near field MI waves. The proposed approach is based on excitation of a point source, which is a common case in a practical WUSN. The frequent usage of square lattice MI structure is investigated. To verify the mathematical derivation, the simulation of time domain based on the fourth-order Runge-Kutta (RK) method is carried out. Simulation results show that the new model can provide a precise prediction to the MI wave's propagation, with the computation load being one-tenth of that of the time domain simulation. The characteristics of the propagation of the MI waves are presented and discussed. Finally, the reflection on the edge of the MI structure is reduced by analysing the terminal matching conditions and calculating a method for matching impedances.

A method of distortion correction based on parallel lines is presented, not only for radial distortion coefficient but also for tangential distortion coefficients. Firstly, an approximate line passing through the center is approached by anamorphic curves. The coefficient of distortion is combined with the vision process to correct an anamorphic image for the final calibration of the liner model. Secondly, the point with only tangential distortion is gained by the actual point minus radial distortion. The distances from the point with tangential distortion and the ideal point to the principal point are equivalent. The Least-squares method is used to fit lines in theory, and the coefficients of tangential distortion are gotten.

：The end-force measurement of minimally invasive surgical puncture probes is crucial for achiev• ing precise control of such probes，improving the quality of surgeries，and ensuring the safety of surgical operations. In this study，a fiber optic force sensor with a Fabry-Pérot(F-P)-cavity-cascaded fiber Bragg grating(FBG)that can be integrated into the probe is designed to meet the actual requirements for measur• ing the force at the end of a puncture surgical probe. First，based on the double-beam interference theory of the F-P cavity and fiber grating sensing theory combined with the cantilever beam structure of the probe，the F-P cavity and FBG of the fiber optic sensor implanted in the probe sensing model are ana• lyzed. Then，the mapping relationship between the characteristic wavelength shift of the F-P cavity and the FBG and the applied force are deduced，with the force and temperature sensitivity matrix being intro• duced to realize the probe force measurement while effectively avoiding the cross-influence problem of tem •

A novel technology for the simultaneous and independent measurement of dual parameters is proposed and experimented. By using a single fiber Bragg grating half-pasted by 1C-LV epoxy under different curing conditions, the sensor structure is designed such that the reflective single-peak spectrum splits into a twin-peak spectrum, which makes the FBG spectrum form a natural spectral peak splitting bias. A measurement limitation exists in the FBG sensor packaging at room temperature, which can be solved by the high-temperature cured packaging method. To verify the validity of the theory and methodology, the experimental system is used. In the range from –1000 to +1000 με and from 35 to 75°C, the Bragg wavelength change is relative linear to the strain and temperature. The temperature and strain variations can be independently and simultaneously measured using the split peak, and the deviations of the FBG sensor are ±1°C and ±5 με, respectively. This single FBG sensor can realize dual-parameter measurement, which is valuable for narrow-space health monitoring.