Integration of an Axially Continuous Graphene with Functional Metals for High-Temperature Electrical Conductors

Demands for effective high-temperature electrical conductors continue to increase with the rapid adoption of electric vehicles. However, the use of conventional copper-based conductors is limited to relatively low temperatures due to their poor oxidation resistance and microstructural instability. Here, a highly conductive and thermally stable nickel-graphene-copper (NiGCu) wire that combines the advantages of graphene and its metallic components is developed. The NiGCu wire consists of a conductive copper core, an oxidation-resistant nickel shell, and axially continuous graphene embedded between them. The experiments on 10–80 µm diameter NiGCu wires demonstrate substantial enhancements in electrical properties and thermal stability across a variety of metrics. For instance, the smallest NiGCu wires have a 61.2% higher current density limit, 307.6% higher conductivity, and an order of magnitude smaller change in resistivity compared to conventional Ni-coated Cu counterparts after annealing at 650 °C. By performing both innovative experiments and simulations using different sizes of NiGCu wires, the diffusion coefficients of metals are quantified, for the first time to the best knowledge, through continuous graphene. These results indicate that the dramatic improvement in thermo-electrical properties is enabled by the embedded graphene layer which reduces Ni Cu interdiffusion by ≈10⁴ times at 550 °C and 650 °C.     

Evolution from ancient medication to human-centered Healthcare 4.0: A review on health care recommender systems

The evolution of intelligent and data-driven systems has pushed for the tectonic transition from ancient medication to human-centric Healthcare 4.0. The rise of Internet of Things, Internet of Systems, and wireless body area networks has endowed the health care ecosystem with a new digital transformation supported by sophisticated machine learning and artificial intelligence algorithms. Under this umbrella, health care recommendation systems have emerged as a driver for providing patient-centric personalized health care services. Recommendation systems are automatic systems that derive the decisions on the basis of some valid input parameters and vital health information collected through wearable devices, implantable equipments, and various sensor. Therefore, to understand the state-of-the-art developments in the health care ecosystem, this paper provides a comprehensive survey on health care recommendation systems and the associated paradigms. This survey starts from the ancient health care era and move toward the Healthcare 4.0 in a phased manner. The road map from Healthcare 1.0 to Healthcare 4.0 is analyzed to highlight different technology verticals supporting the digital transformation. This study also provides the systematic review of the health care systems, the types of health care systems, and the recommender systems. Moreover, a deep analysis of health care recommender systems and its types is also presented. Finally, the open issues and challenges associated with the adaption and implementation of human-centric Healthcare 4.0 ecosystem are discussed. This is provided to find out the possible research questions and gaps so that the corresponding solutions could be developed in the near future.