Subway system has been widely applied to the urban rail transit system. However, many negative impacts such as the electrochemical corrosion on the subway track and third-party buried metallic infrastructure caused by the stray current, has gradually appeared. This kind of electrochemical corrosion will cause a great threat on buried metallic structure and personal safety. Numerous scholars studied this from various aspects, in which the stray current model is extensively used as an effective means of analysis. In this paper, the existing stray current distributing model is firstly reviewed and analyzed. Secondly, rail potential problem analyzed by means of the stray current distributing model is reviewed. Thirdly, stray current simulation methods are also presented and discussed based on the stray current distributing model. At last, the developing direction and trend of stray current distributing model in the future study is point out based on the content reviewed above.

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Fiber optic current sensor based on magnetostrictive composite material is suitable for multiple industrial fields. Aiming at increasing the low sensitivity caused by conventional magnetostrictive composites, this work designed optimized magnet focusing structure of magnetostrictive composite material to develop high-performance fiber optic current sensor. The influence of magnetic focusing structures on the performance of current sensor was analyzed and validated through theoretical modeling and finite element-based simulation. Experimental tests were carried out to validate the superiority of proposed sensor compared with the existing sensors. Results show that section B in the magnetostrictive composite material leads to the difference in magnet field distribution, and the proposed sensor is more sensitive than the sensors with conventional structure. A repeatability error of 2.5%, a sensitivity of 0.16952 με/A, and a linearity of 2.2 % can be achieved by the proposed hourglass type sensor with low-cost and wide range between 0 and 900 A.

The grating projection‐based three‐dimensional (3D) measurement technique has been widely used in various fields, such as industrial inspection, cultural relic protection, and reverse engineering. However, due to the nonlinear response between the input and output of the measurement system, phase measurement errors occur, which reduces the accuracy of 3D reconstruction, which is known as the gamma effect. To address this issue, a novel method has been proposed to reduce the nonlinear response of the system. Ultimately, this method reduces the impact of the gamma value on the phase accuracy in subsequent measurements. Experimental results have shown that this method can quickly calibrate the correct precoding gamma value, effectively reduce the gamma nonlinear response during the measurement process, and improve measurement accuracy.