Evaluation of the superficial characteristics of articular cartilage using evanescent waves in the friction tests with intermittent sliding and loading

Evaluation of the effect of collagen network degradation on the frictional characteristics of articular cartilage using a simultaneous analysis of the contact condition

Evaluation of the Effect of Collagen Network Degeneration on the Frictional Characteristics of Articular Cartilage Using a Simultaneous Analysis of the Contact Condition

Systems and methods for the controlled delivery of laser light to target tissue using an improved waveguide. A waveguide controls transmission of wave energy to a target based on direct contact with the target. The waveguide comprises a propagation medium, a cladding causing the electromagnetic wave to be internally reflected in the medium, and an interface formed in the cladding and configured for direct contact with the target. A portion of the laser light penetrates through the cladding at the interface and propagates into the target while a portion internally reflects within the propagation medium.

Guided wave ablation and sensing

In this work, a theoretical analysis on the design of the beam splitter (BS) based on the frustrated total internal re∞ection (FTIR) is made. We consider a model structure made of a low- index gap layer bounded by two high-index layers. In the design of a 50/50 BS, we flnd that there exists a critical gap thickness which is a decreasing function of the angle of incidence for both TE and TM waves. There also exists a critical wavelength for the incident wave, and it increases with increasing angle of incidence. Finally, at a flxed gap thickness and wavelength of incident wave, the critical angle in TE wave is slightly larger than that of TM wave. The analysis provides some fundamental information that is of particular use to the design of a BS within the framework of FTIR.

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Design analysis of a beam splitter based on the frustrated total internal reflection

The mechanism of frustrated total internal reflection was analyzed according to the theory of optical film. The transmission and reflection functions were developed and the curves of transmission and reflection changing from the relative gap width d / λ , incident angle θ 0 , and refraction index n were shown in graphs. We proposed a scheme of experimental device to test the theoretical conclusion. A self-made electronic actuator drove the piezoelectric ceramics of FTIR. Experiments showed that the evanescent of transmission is 80% for He–Ne laser and smaller for YAG laser and Er:glass laser.

Frustrated total internal reflection evanescent switching

A fiber-optic gyroscope (FOG) with lower precision but higher cost advantage is typically selected according to working conditions and engineering budget. Thermal drift is the main factor affecting FOG precision. External thermal calibration methods by algorithms can effectively weaken the influence of thermal drift. This paper presents a thermal calibration method of a two-dimensional N-order polynomial (TDNP) and compares it with artificial neural network (ANN) methods to determine a software FOG thermal calibration method for landslide displacement monitoring. The TDNP thermal calibration coefficient matrix was established, and the thermal calibration capability of the TDNP method with different orders N was evaluated on the basis of error analysis. The ANN model with 1 to 18 hidden neural layers was established on the basis of LM, BR, and SCG algorithms to choose a suitable ANN. Finally, the mean absolute errors of FOG thermal calibration through the TDNP with different orders and the LM were compared. This method was applied in the Huangtupo landslide area, China. The results highlight that the TDNP method with order 5 had better performance and satisfied the requirements of landslide displacement monitoring. The research results can compensate for the lack of adaptability of the FOG thermal calibration method in landslide displacement monitoring.

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Yu Zhu

Papers

Frustrated total internal reflection evanescent switching

Fiber-Optic Gyroscope Thermal Calibration through Two-Dimensional N-Order Polynomial for Landslide Displacement Monitoring