Wireless power transmission technology based on coil coupling has been widely applied in various fields. However, the performance of the system is affected by the malposition of the transmission coil-couple, which is inevitable in the wireless power transmission system (WPTS). In this study, a multi-transmitter coil array is proposed to build a more uniform magnetic flux density for the WPTS, intending to enhance the performance of the WPTS in the case of coil-couple malposition. The model of the transmission system is built and different coil arrangement methods are analyzed. Then, the magnetic field distributions of the proposed WPTS with different coil arrays are compared using numerical simulations. Experiments are conducted to investigate the performances of the designed WPTS. The results show that WPTS with a seven-coil array can provide a more uniform magnetic field for the WPTS, whose relative deviation of output power is less than 28.55%. This study provides some clues for improving the performance of the WPTS through different arrangements of the transmitter coils.

With the extensive application of wood-based panels in the home decor industry, determining formaldehyde release form wood-based panels (FRWBP) is crucial for ensuring environmental air quality and human health. This article addresses the issues of insufficient monitoring of the testing stages for FRWBP and the difficulty in tracing the operation records of operator during determining FRWBP by the chamber method. It proposes a system for monitoring and analyzing the testing stages of FRWBP based on electrical monitoring. The system employs non-invasive sensing technology that does not interfere with normal testing process to collect real-time electrical usage data from the devices. The data is uploaded to an industrial computer for storage and processing. Statistical features of the electrical time series data are extracted using a sliding window approach and optimized with Principal Component Analysis (PCA). Subsequently, the binary tree support vector machine algorithm (BTSVM) optimized by k-means clustering algorithm is used to identify the detection states of the wood-based panels. Experimental results show that the system can achieve traceability of the formaldehyde detection stage records of artificial boards, and the designed algorithm model can also effectively identify the detection status of wood-based panels. The system and methods proposed in this paper have significant prospects for implementation in monitoring and traceability management within the testing industry.

This article presents a coil couple-based transcutaneous energy transmission system (TETS) for wirelessly powering implanted artificial hearts. In the TETS, the performance of the system is commonly affected by the change in the position of the coupling coils, which are placed inside and outside the skin. However, to some extent, the influence of coupling efficiency caused by misalignment can be reduced by optimizing the coil. Thus, different types of coils are designed in this paper for comparison. It has been found that the curved coil better fits the surface of the skin and provides better performance for the TETS. Various types of curved coils have been designed in response to observed bending deformations, dislocations, and other coupling variations in the curved coil couple. The numerical model of the TETS is established to analyze the effects of the different types of coils. Subsequently, a series of experiments are designed to evaluate the resilience to misalignment and to verify the heating of the coil under conditions of severe coupling misalignment. The results indicated that, in the case of misalignment of the coils used in artificial hearts, the curved transmission coil demonstrated superior efficiency and lower temperature rise compared to the planar coil.

This paper proposes a semi-blind receiver for estimating channel parameters such as arrival angle, departure angle, channel gain, and Doppler frequency offset in a dual hop time-varying MIMO-OFDM system. The received signal of the destination node follows the form of four nested PRAFAC model. Exploiting this structure, a four stage alternating least squares receiver algorithm is proposed without using pilots. This paper also briefly analyzes the identifiability conditions of the proposed algorithm, and derives the range of system parameters. Finally, simulation experiments show that the proposed algorithm is superior to least square receiver in estimating the normalized mean square error of the channel and bit error rate.