Fe–Co alloys are attracting attention as magnetostrictive materials for energy harvesting and sensor applications. This work investigated the magnetostriction characteristics and crystal structure of additive-manufactured Fe–Co alloys using directed energy deposition. The additive-manufactured Fe–Co parts tended to exhibit better magnetostrictive performance than the hot-rolled Fe–Co alloy. The anisotropy energy ΔK₁ for the Fe–Co bulk, prepared under a power of 300 W (referred to as bulk−300 W), was larger than for the rolled sample. For the bulk−300 W sample in a particular plane, the piezomagnetic constant d was large, irrespective of the direction of the magnetic field. Elongated voids that formed during additive manufacturing changed the magnetostrictive behavior in a direction perpendicular to these voids. Magnetic property measurements showed that the coercivity decreased. Since sensors should be highly responsive, Fe–Co three-dimensional parts produced via additive manufacturing can be applied as force sensors.

Laser metal deposition (LMD) has demonstrated its ability to produce complex parts and to adjust material composition within a single workpiece. It is also a suitable additive manufacturing (AM) technology for building up dissimilar metals directly. However, brittle intermetallic compounds (IMCs) are formed at the interface of the dissimilar metals fabricated by LMD. Such brittle phases often lead to material failure due to thermal expansion coefficient mismatch, thermal stress, etc. In this work, we studied a Fe-Ti system with two brittle phases, such as FeTi and Fe₂Ti, as a model system. Fe was grown on top of Ti at various process parameters. The morphologies and microstructures were characterized by optical microscopy (OM) and scanning electron microscopy (SEM). No cracks along the interface between pure Ti and bottom of the solidified melt pool were observed in the cross-sectional images. Chemical composition in the fabricated parts was measured by Energy-dispersive X-ray spectroscopy (EDS). Electron backscatter diffraction (EBSD) was performed in addition to EDS to identify the crystalline phases. The Vickers hardness test was conducted in areas with different phases. The chemical composition in the melt pool region was found to be a determining factor for the occurrence of major cracks.

In this paper, the principle, structure of the Active Power Filter (APF) system and PWM control are all discussed, and based on the improved instantaneous reactive power theory, a kind of fast feasible algorithm for distortion currents detection, harmonic current suppression and reactive power compensation in shunt active power filter is put forward, meanwhile, considering the problem of power devices active power loss in the main circuit, compensating current feedback and DC bus link voltage control are added, finally, a shunt active power filter for typical current harmonic source with thyristor rectifier load is simulated based on MATLAB/Simulink toolbox, by the detailed simulation experiments, in-depth research and analysis of the simulation results, the correctness and feasibility of the compensation scheme for harmonic current detection and APF system are all verified. The proposed scheme of the harmonic current suppression and reactive power compensation is achieved, which can provide a good reference to the research and design of APF.

This chapter examines the use of mobile messaging apps in relationship management. To contextualize the discussion, the authors focus on WeChat, a dominant mobile messaging service in China that has over 1 billion monthly active users, as a case to examine the mutual shaping between technological affordances and social contexts. This chapter first introduces the case of WeChat and discusses its main affordances related to mobile messaging. The chapter then presents a discussion of the use of WeChat messaging in relationship management and users’ sociocultural construction of technology. This chapter aims to present a mutual shaping process between the affordances of mobile messaging apps and users’ relational practices.