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The aim of this work is to develop materials that can absorb microwave to meet the requirements of stealth technology and solve the problem of electromagnetic pollution. However, the challenge is having materials with high-efficient absorption properties at an ultralow filling rate and visualizing the microwave response. The strategy used in this work was to integrate point defect and microstructure in preparing materials, nitrogen-doped reduced graphene oxide@ carbon nanofibers with high-efficient microwave absorption and double-layered structure. Ethylenediamine (nitrogen source), was doped into the materials, resulting in the generation of the defects. The microwave absorption performance of the materials was affected by the degree of defects due to the dipole polarization loss and conductive loss. The optimal samples gained the maximum reflection loss of -54.7 dB and effective absorption bandwidth of 4.74 GHz at a filling rate of only 8 wt%. More significantly, the microwave absorbing mechanism was analyzed visually in the response field. Furthermore, the actual stealth effects were evaluated by the radar cross section reduction, and the value was 29.2 dBm

As a response to stealth technology and electromagnetic pollution, microwave absorbing materials have attracted the attention of many research scholars. However, achieving effective absorption with a low filling level is still a challenge in the harsh environment. Here, an emerging carbon-carbon composite fiber with a core-sheath structure is cleverly tailored for high-performance microwave absorber by tuning the dielectric loss. Reasonable engineering heterogeneous interfaces and conductive paths give rise to a synergistic effect of the impedance matching, conductive loss, polarization loss and multiple scattering. The obtained CR-800 achieves the maximum reflection loss of -51.91 dB, effective absorbing bandwidth of 4.82 GHz, and radar cross section (RCS) reduction value of 41.5 dBm

The superhydrophobic flower-like OTS-SiO2 particles with tunable size were synthesized for application in anti-icing technology, in which the nanosilica fibers were grown on surface of SiO2 sphere. Furthermore, the anti-icing process of flower-like OTS-SiO2 particles was investigated by a high speed video and thermal infrared imaging equipment. It was found that the flower-like OTS-SiO2 particles with a diameter of 300.0 nm showed best anti-icing ability, in which the frozen time of water droplets could be prolonged to 564.0 s at −25.0℃. The good anti-icing ability was attributed to micro-nano hierarchical structure and surface modification of flower-like OTS-SiO2 particles. The work has an important guiding implication for the subsequent design and preparation of superhydrophobic particles for application in anti-icing technology.

In this study, self-assembled three-dimensional (3D) reduced graphene oxide/nickel (rGO/Ni) nanofibers with hierarchical core-shell structure and vertically aligned graphene edge planes are synthesized as an efficient microwave absorption material. Electromagnetic multifunctional Ni chains form the skeleton of 3D nanofibers, and 2D rGO nanosheets are wrapped around the 1D Ni chain to form 3D rGO/Ni nanofibers via electrostatic self-assembly combined with a reduction method. Compared with the pristine Ni chain or rGO sheet, the unique vertically aligned graphene edge plane gives the 3D rGO/Ni nanofiber a much larger specific surface area and interlaced area between the 3D nanofibers. The hierarchical core-shell structure also provides abundant interfaces between the rGO and Ni chains, giving the 3D rGO/Ni nanofibers effective interfacial polarization loss. As a result, the 3D rGO/Ni nanofibers exhibit excellent microwave absorption properties. At a thickness of 2 mm, the minimum reflection loss of the nanofibers with only 15 wt% loading in paraffin reaches −50.52 dB, and the effective absorption bandwidth achieves 4.2 GHz. Moreover, the 3D rGO/Ni nanofibers also exhibit excellent dispersibility because of their special edge plane structure. This work provides an effective strategy for designing high-performance microwave absorption materials and is promising for applications in efficient electronics protection.

The design of satisfied catalytic activity and stable catalysts for the oxygen evolution reaction (OER) is crucial in the production of hydrogen in electrolyzed water. Herein, S-doping NiCo-metal organic framework (NiCoS-MOF) were prepared successfully in situ on a nickel foamed (NF) substrate by used terephthalic acid (TPA) as an organic ligand via the original one-step solvothermal process, NiCoS-MOF reveals the electrocatalytic performance by the low overpotential of 71 mV at 10 mA cm−2 and the tafel slope of 74.4 mV dec−1 under alkaline condition (1 M KOH) served as OER electrodes directly. The i-t curve for 48 h at 1.50 and 2.14 V (vs.REH) showed excellent stability of NiCoS-MOF and the structure had no significant collapse after 1000 cycles. Superior OER activity and excellent stability could ascribed to the fluffy and orderly petal-like structure, which exhibited dispersal of the active sites and facilitated the evolution of oxygen during the catalysis process. The work enriched exploration of heteroatom-doped bimetallic MOFs in energy storage and conversion.

Ultra-small and monodispersed Pt nanoparticles (NPs) have been successfully synthesized in polymer electrolyte membrane fuel cells. The process normally involves the use of capping agents, organic species, templates, and substrates and is thus complex. Hence, obtaining Pt NPs with a clean surface is challenging. In this study, a method for preparing stable and highly dispersed Pt NPs with clean surfaces is proposed. The method involves the use of a modified Na3C6H5O7 reduction process assisted by NaNO3 stabilization. The specific complexations of NO2− ions possibly alter the reaction kinetics and lower the growth rate of Pt NPs by retarding the reduction reaction. The optimized Pt/carbon nanotube (CNT) catalysts exhibit high mass activity and moderate activity decay after 10,000 times of potential cycling compared with commercially available Pt/C catalysts. Then, membrane electrode assemblies based on the resultant catalysts are characterized. The cell performance of 744 mW cm−2 (maximum power density) is achieved after the optimized Pt/CNT catalysts are used in carbon black.

Under investigation in this paper is a higher-order nonlinear self-dual network equation, which may simulate the wave propagation in a ladder type electric circuit. By means of the N-fold Darboux transformation and symbolic computation, the N-soliton solutions in determinant form are obtained. Based on the asymptotic and graphic analysis, the elastic interaction phenomena between/among two-, three- and four-soliton solutions are discussed, and some important physical quantities are accurately analyzed. Numerical simulations are used to explore the dynamical stability of one- and two-soliton solutions. Results might be helpful for understanding the propagation and interaction properties of electrical signals in a ladder type nonlinear self-dual network.

a new metal-free ternary composites based on organic molecular, N doped graphene quantum dots (N-GQDs) and g-C3N4 was developed. The photocatalytic activity was evaluated for photocatalytic degradation of organic pollutant. It showed high photocatalytic degradation rate (ca. 0.25 mg/min) and ultra-short photocatalytic time (ca. 3.0 min) for complete degradation of organic dye (eg, RhB) in water. The enhanced photocatalytic performance was attributed to the synergistic effect of organic molecule and graphene quantum dots, enhancing visible light absorption, suppressing recombination of photogenerated charges and accelerating photoredox reaction of g-C3N4. The study did not only propose a facile method to synthesis of free-metal photocatalysts with ultra-fast photocatalytic rate, but also represented a new method to improve the photocatalytic activity of photocatalysts based on carbon materials.

The role of biochar as the redox catalyst in the removal of reductive pollutants from soil and water system has been extensively studied recently, but there is still a lack of qualitative description of its specific mechanisms in redox processes. In this study, the mechanism of biochar in the transformation process of γ-HCH under anoxic condition was revealed by the compound-specific isotope analysis. The concentration and carbon isotopic composition (δ

Silicon microstrip detectors with floating strips have nonuniform charge collection efficiency. This nonuniformity depends on the incident position and incident angle and should be corrected during charge reconstruction. A novel charge reconstruction algorithm, called the charge sharing algorithm, is introduced to correct this nonuniformity. This algorithm assumes that the nonuniformity in charge collection efficiency is due to charge sharing through the capacitors and resistors of silicon microstrip detectors. This charge sharing assumption is tested in this paper using electrical characterization and SPICE simulation.

With the growing challenges of modern electronics in heat dissipation, developing thermal management materials with high thermal conductivity and electrical insulation property remains an important issue for electronics. In this work, a novel three-dimensional network (3D) of boron nitride/reduced graphene oxide (BN/rGO) with covalent bond connections were fabricated by using the surface modification and ice-templated methods. The as-prepared boron nitride/reduced graphene oxide/nature rubber composites (BN/rGO/NR) possessed an enhanced through-plane thermal conductivity of 1.28 W m−1 K−1 and satisfactory electrical insulation at a low filler loading of 4.9 vol%. The results demonstrated that the covalent bond connections and three-dimensional networks of fillers greatly reduced the interfacial thermal resistance as well as phonon scatterings at the filler/filler and filler/matrix interface simultaneously. More importantly, this strategy provided a creative insight to the design of advanced thermal management materials and also presented a bright application prospect for next-generation electronic packing.

Tris(2-chloroethyl) phosphate (TCEP), as a typical chlorinated flame retardant, is attracting more attention as a carcinogen. Although persulfate-based oxidation exhibits good performance in removing refractory organic pollutants, the kinetics of persulfate-based remediation are affected by inorganic anions, which causes inaccurate remediation efficiency. This study combines steady-state radical concentration modelling with isotope fractionation to investigate the effects of inorganic anions on TCEP degradation by UV/persulfate (UV/PS). In the absence of anions during UV/PS system, the observed degradation rate was (9.7 ± 0.1) × 10

In this study, 4-(4-aldehyde-phenoxy) phthalo nitrile (AlPPN) was firstly synthesized from the reaction between nitro groups of 4-nitrophthalonitrile and hydroxyl groups of p‑hydroxy benzaldehyde, and then 4-β-(4-aldehyde-phenoxy)cobalt phthalocyanine (CoAlPc) was prepared by means of the reaction between AlPPN and cobalt chloride catalyzed by DBU. Finally, CoAlPc was covalently immobilized onto amino-modified GO surface via the Schiff-base reaction to prepare CoAlPc/GO hybrids. Their structure and morphology were characterized by FT-IR, TEM, XRD and UV–Vis absorption spectra. These samples are tested for photocatalytic degradation of phenol under visible light irradiation. The loading of CoAlPc on support materials is to the benefit of its photocatalytic activity, and the photocatalytic activity of CoAlPc supporting on GO is higher than that on polyglycidyl methacrylate-modified silica (PGMA/SiO2). The dosage of CoAlPc/GO has significant effects on the photocatalytic degradation of phenol under visible light irradiation. A low dosage (0.2 g/L) of CoAlPc/GO exhibits the best photoactivity, whose degradation rate for phenol achieves 100% for 5 min and the intermediate (o-benzoquinone) mineralizes completely for 1 h in the presence of H2O2 under visible light irradiation. CoAlPc/GO still has stable photocatalytic activity after repeated use for 7 times.

Copper oxide (CuO) particles with loose agglomeration of porous flakes were treated by ultrasound in different solvents. CuO particles with completely discrete flakes were obtained with ultrasonic surface treatment in ethyl alcohol as a polar solvent while CuO particles with compacted flake agglomeration were found after ultrasonic treatment in diethyl ether as a non-polar solvent. CuO particles after ultrasonic treatment were characterized to investigate the effects of morphological appearance on size distribution, sedimentation velocity, specific surface area, ultraviolet-visible (UV–vis) absorption spectra, diffraction angle of X-ray diffraction (XRD) pattern, binding energy of X-ray photoelectron spectroscopy (XPS), Raman intensity and dissolution rate. CuO particles with completely discrete flakes exhibited a fastest dissolution rate of 7 s in 12.5 vol% H2SO4 for rapid complement of cupric ions so that the electrolyte for copper electrodepositon could meet the requirement of stable concentration of cupric ions to generate fine copper deposits in a plating system with insoluble anode.

N-substituted bis(diphenylphosphanyl)amine RN(PPh 2 ) 2 (PNP; R = CH 2 CH 2 CH 2 Si(OEt) 3 ) and its mononuclear nickel(II) ethanedithiolate complexe RN(PPh 2 ) 2 Ni(SCH 2 CH 2 S) (PNS; R = CH 2 CH 2 CH 2 Si(OEt) 3 ) were prepared and used as multi-element flame retardants for epoxy resin (EP). Results of thermogravimetric analysis (TGA) revealed that the incorporation of PNP or PNS restrained the decomposition of EP and also improved the stability of char residues. Moreover, results of limited oxygen index (LOI), vertical burning test (UL-94), microscale combustion calorimeter (MCC), and cone calorimeter tests proved that both PNP and PNS endowed EP with good flame retardancy. Different chemical structures and action mechanisms of PNP and PNS resulted in different degrees of flame retardancy for EP. Although EP/PNP samples caused a little higher LOI values than those of EP/PNS ones, the incorporation of 7 wt% PNS endowed EP with a lower peak of heat release rate (PHRR) and total smoke production (TSP), thereby indicating better flame-retardant and smoke suppression effects. Furthermore, thermogravimetry-Fourier transform infrared spectroscopy (TG-FTIR) and pyrolysis gas chromatography/mass spectrometry (Py-GC/MS) were employed to analyze the pyrolysis behavior of EPs and flame retardants. The morphologies of char layers for EPs were examined by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). In comparison to PNP, PNS promoted the formation of a stronger protective char barrier comprising by P/Si/S/Ni elements and also restrained the effects of flammable gases on EP.