Construction of multiple interfaces and dielectric/magnetic heterostructures in electromagnetic wave absorbers with enhanced absorption performance:A review

The construction of structures with multiple interfaces and dielectric/magnetic heterostructures enables the design of materials with unique physical and chemical properties,which has aroused intensive interest in scientific and technological fields.Especially,for electromagnetic(EM)wave absorption,enhanced interface polarization and improved impedence match with high Snoek's limitation could be achieved by multiple interfaces and dielectric/magnetic heterostructures,respectively,which are benificial to high-efficiency electromagnetic wave absorption(EWA).However,by far,the principles in the design or construction of structures with multiple interfaces and dielectric/magnetic heterostructures,and the relationships between those structures or heterostructures and their EWA performance have not been fully summarized and reviewed.This article aims to provide a timely review on the research progresses of high-efficency EM wave absorbers with multiple interfaces and dielectric/magnetic heterostructures,focusing on various promising EWA materials.Particularly,EM attenuation mechanisms in those structures with multiple interfaces and dielectric/magnetic heterostructures are discussed and generalized.Furthermore,the changllenges and future developments of EM wave absorbers based on those structures are proposed.

In-situ building of multiscale porous NiFeZn/NiZn-Ni heterojunction for superior overall water splitting

The development of efficient nonprecious bifunctional electrocatalysts for water electrolysis is crucial to enhance the sluggish kinetics of the oxygen evolution reaction(OER)and hydrogen evolution reaction(HER).A self-supporting,multiscale porous NiFeZn/NiZn-Ni catalyst with a triple interface heterojunction on nickel foam(NF)(NiFeZn/NiZn-Ni/NF)was in-situ fabricated using an electroplating-annealing-etching strategy.The unique multiinterface engineering and three-dimensional porous scaffold significantly modify the mass transport and electron interaction,resulting in superior bifunctional electrocatalytic performance for water splitting.The NiFeZn/NiZn-Ni/NF catalyst demonstrates low overpotentials of 187 m V for HER and 320 mV for OER at a current density of 600 mA/cm~2,along with high durability over 150 h in alkaline solution.Furthermore,an electrolytic cell assembled with NiFeZn/NiZn-Ni/NF as both the cathode and anode achieves the current densities of 600 and 1000 m A/cm2 at cell voltages of 1.796 and 1.901 V,respectively,maintaining the high stability at 50 mA/cm2 for over 100 h.These findings highlight the potential of NiFeZn/NiZn-Ni/NF as a cost-effective and highly efficient bifunctional electrocatalyst for overall water splitting.

Designing multi-heterogeneous interfaces of Ni-MoS_(2)@NiS_(2)@Ni_(3)S_(2)hybrid for hydrogen evolution

The transition metal chalcogenides represented by MoS_(2)are the ideal choice for non-precious metal-based hydrogen evolution catalysts.However,whether in acidic or alkaline environments,the catalytic activity of pure MoS_(2)is still difficult to compete with Pt.Recent studies have shown that the electronic structure of materials can be adjusted by constructing lattice-matched heterojunctions,thus optimizing the adsorption free energy of intermediates in the catalytic hydrogen production process of materials,so as to effectively improve the electrocatalytic hydrogen production activity of catalysts.However,it is still a great challenge to prepare heterojunctions with lattice-matched structures as efficient electrocatalytic hydrogen production catalysts.Herein,we developed a one-step hydrothermal method to construct Ni-MoS_(2)@NiS_(2)@Ni_(3)S_(2)(Ni-MoS_(2)on behalf of Ni doping MoS_(2))electrocatalyst with multiple heterogeneous interfaces which possesses rich catalytic reaction sites.The Ni-MoS_(2)@NiS_(2)@Ni_(3)S_(2)electrocatalyst produced an extremely low overpotential of 69.4 mV with 10 mA·cm^(−2)current density for hydrogen evolution reaction(HER)in 1.0 M KOH.This work provides valuable enlightenment for exploring the mechanism of HER enhancement to optimize the surface electronic structure of MoS_(2),and provides an effective idea for constructing rare metal catalysts in HER and other fields.

Environment-Stable CoxNiy Encapsulation in Stacked Porous Carbon Nanosheets for Enhanced Microwave Absorption

Magnetic/dielectric@porous carbon composites,derived from metal–organic frameworks(MOFs)with adjustable composition ratio,have attracted wide attention due to their unique magnetoelectric properties.In addition,MOFs-derived porous carbon-based materials can meet the needs of lightweight feature.This paper reports a simple process for synthesizing stacked CoxNiy@C nanosheets derived from CoxNiy-MOFs nanosheets with multiple interfaces,which is good to the microwave response.The CoxNiy@C with controllable composition can be obtained by adjusting the ratio of Co^2+ and Ni^2+.It is supposed that the increased Co content is benefit to the dielectric and magnetic loss.Additionally,the bandwidth of CoNi@C nanosheets can take up almost the whole Ku band.Moreover,this composite has better environmental stability in air,which characteristic provides a sustainable potential for the practical application.

A survey on automatic dashboard recommendation systems

This paper presents a survey on automatic or semi-automatic recommendation systems that help users create dashboards.It starts by showing the important role that dashboards play in data science,and gives an informal definition of dashboards,i.e.,a set of visualizations possibly with linkage,a screen layout and user feedback.We are mainly interested in systems that use a fully or partially automatic mechanism to recommend dashboards to users.This automation includes the suggestion of data and visualizations,the optimization of the layout and the use of user feedback.We position our work with respect to existing surveys.Starting from a set of over 1000 papers,we have selected and analyzed 19 papers/systems along several dimensions.The main dimensions were the set of considered visualizations,the suggestion method,the utility/objective functions,the layout,and the user interface.We conclude by highlighting the main achievements in this domain and by proposing perspectives.