A magnetic field-circuit coupling model for functionality and interface simulation test of railway Balise

Railway Balise is widely used in the Balise-based train control system to provide accurate location information for the safe operation of trains. In order to evaluate and analyze the functionality and interface test of a new designed Balise more rigorously and accurately, this paper build a magnetic field-circuit coupling model to quantify the internal physical function and external interface performance of the Balise. Based on the electromagnetic field theory, the down-link and up-link magnetic field models were set up which describes the relationship between the Balise and the test antenna. Then based on the equivalent circuit model, the energy conversion circuit model and the data transmission circuit model were derived, and the complete coupling model is established for functionality and interface simulation tests. Moreover, the physical behavior and interface characteristic of Balise in different situations are validated and analyzed, followed by the analysis of magnetic field conformity, I/O characteristics, impedance, start-up behavior, and up-link signal characteristics. The results show the start-up time of the Balise functionality test decreases with increasing down-link magnetic field. Furthermore, Balise impedance can be used as a new dynamic detection parameter of the Balise. Finally, the down-link magnetic field will slightly affect the uplink signal characteristics

N‑Doped Amorphous Carbon Coated Fe₃O₄/SnO₂ Coaxial Nanofibers as a Binder-Free Self-Supported Electrode for Lithium Ion Batteries

N-doped amorphous carbon coated Fe₃O₄/SnO₂ coaxial nanofibers were prepared via a facile approach. The core composite nanofibers were first made by electrospinning technology, then the shells were conformally coated using the chemical bath deposition and subsequent carbonization with polydopamine as a carbon source. When applied as a binder-free self-supported anode for lithium ion batteries, the coaxial nanofibers displayed an enhanced electrochemical storage capacity and excellent rate performance. The morphology of the interwoven nanofibers was maintained even after the rate cycle test. The superior electrochemical performance originates in the structural stability of the N-doped amorphous carbon shells formed by carbonizing polydopamine