Journal of Electronic Science and Technology最新文献

Wireless communications have become an integral part of global convergence as global connectedness has gradually become dependent on its efficient deployment. The need for “more-broadband” techniques in relation to the ever increasing growth rate of the data hungry society now necessitates novel techniques for the high-speed data transmission. While advancements have been made in this regard, the projection of having an eventual Internet of everything (IoE) deployment will result in an unimaginable transmission data rate requirement as huge data traffic will be conveyed per time within the communications network, which will require a capacity upgrade of the existing infrastructure. Visible light communications (VLCs), as an integral part of optical wireless communications (OWCs), have been reviewed in this article, having the capacity to extend the achievable data rate requirement of the wireless communications network. The technologies, techniques, and best practices have been presented alongside technology integration for the seamless high capacity wireless broadband deployment.

The II-VI based magnetic semiconductors with a direct and wide optical bandgap are expected to show high potential for optical applications utilizing short wavelength laser diodes (LDs), such as 532-nm green and 475-nm blue LDs. We have confirmed that the Faraday rotation θ_F in the ZnMnTe and ZnMnSe films deposited on quartz glass (QG) and sapphire (SA) substrates by using molecular beam epitaxy (MBE) is large near the absorption edge. This paper reports the magneto-optical properties of ZnMnTe and ZnMnSe films synthesized on the QG and SA substrates, and shows the result of a direct Faraday rotation observation successfully made for the ZnMnTe films under 1.28-kHz alternating magnetic fields. The optical absorption characteristics of the ZnMnTe films grown on the SA substrates by MBE are discussed by comparing them with the optical absorption properties and photoluminescence spectra of the II-VI ZnTe parent single crystals.

This paper describes the development of an intelligent automated control system of a robot manipulator for plasma treatment of medical implants with complex shapes. The two-layer coatings from the Ti wire and hydroxyapatite powders are applied on the surface of Ti medical implants by microplasma spraying to increase the biocompatibility of implants. The coating process requires precise control of a number of parameters, particularly the plasma spray distance and plasma jet traverse velocity. Thus, the development of the robotic plasma surface treatment involves automated path planning. The key idea of the proposed intelligent automatic control system is the use of data of preliminary three-dimensional (3D) scanning of the processed implant by the robot manipulator. The segmentation algorithm of the point cloud from laser scanning of the surface is developed. This methodology is suitable for robotic 3D scanning systems with both non-contact laser distance sensors and video cameras, used in additive manufacturing and medicine.

This paper discusses consensus tracking of single-integrator multi-agent systems with a time varying reference state based on the least squares estimation theory to deal with the case of communications disturbance. Since none of the followers can communicate with the leader within the accepted time due to communications disturbance, least squares estimation is applied for online estimation of the time varying reference state and reducing the tracking errors occurred due to communications disturbance. A theoretical proof is provided under some assumptions while the necessary and sufficient conditions are demonstrated for which consensus is reached on the time-varying reference state in case of communications disturbance. Finally, a Matlab example is given to validate the effectiveness of the proposed approach.

We synthesized octapod Cu–Au bimetallic alloy with a concave structure by employing a replacement reaction between AuPPh₃Cl and Cu nanocubes. Using Cu nanocube as sacrificial templates, we have successfully generated high-active sites on alloy nanocrystals by carefully tuning the replacement reaction and growth. The key is to afford the proper concentration of AuPPh₃Cl-TOP to the reaction solution. When the Au precursor with high concentration is injected into the galvanic replacement reaction, growth dominates the process, hollowed octapod Cu–Au alloy was obtained. In contrast, when the concentration of the Au precursor is low, the replacement reaction can only take place at the nanocrystals, leading to generated Cu–Au nanocages. This work provides an effective strategy for the preparation of hollow bimetallic nanocrystals with high-active sites.

In this work, the classic molecular dynamics simulations are employed to investigate the atomic structural modification of fused silica with defects as laser irradiation. The dynamics evolution of the atomic structure of fused silica is modeled during energy deposition. The structure parameters such as pair distribution functions (PDFs), bond angle distributions (BADs), and the coordination number are given. The calculated results reveal that fused silica undergoes significant changes in terms of Si–O, Si–Si, and O–O bond lengths, Si–O–Si and O–Si–O bond angles, and the Si and O coordination numbers during laser irradiation. The effects of different surface defects on the micro-structure of fused silica are discussed too. The simulation results of molecular dynamics may help to understand the role of defects in the radiation effect of fused silica.