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This paper proposed a new structure of full-mobility parallel robot, which combined the advantages of high-rotational capabilities and structural simplification, for high-speed operations of material handling. The proposed robot structure integrates lightweight and simple linkages with a relatively complex (i.e., compared to the single platform with limited rotational capability) articulated mechanism or gear train as wrist mechanism to amplify the end-effector rotations, but without significantly increased structural complexity of gearbox, compared to the existing designs. Parametric modeling are carried out for position analysis, workspace evaluation, singularity identification and dynamic characterization to qualify the proposed robot. Moreover, the structure of the proximal links are designed with topology optimization to ensure design requirements of stiffness and low inertia. The performance evaluation shows that the proposed robot can be of high potential application in the industrial production line. • A new design of a full-mobility parallel robot for pick-and-place operation. • Integrated lightweight and simple linkages of robot structure with high-rotational capability. • Combined partial advantages and discarded shortcomings of the existing robot counterparts. • Comprehensively singularity analysis to find a large regular workspace. • An integrated dimensional synthesis of the proximal link by topology optimization. [ABSTRACT FROM AUTHOR]

Graphical abstract Fe/ZnFe 2 O 4 or Fe@ZnFe 2 O 4 flakes or microspheres were produced by an in-situ growth method and their effective absorption properties covered 6.2 GHz. Abstract In this research, a facile in-situ growth method was applied to load ZnFe 2 O 4 nanoparticles on carbonyl iron (Fe) flakes. These loaded ZnFe 2 O 4 exhibited cone shape with an average size of ∼200 nm. The results revealed that the frequency region with reflection loss <−10 dB (f E) was up to 6.2 GHz (d = 1.5 mm), suggesting excellent wideband electromagnetic absorption (EM) properties. The electromagnetic absorption mechanism was discussed in depth which attributed to the synergetic effect of Fe and ZnFe 2 O 4. The loaded ZnFe 2 O 4 played a key role on suppressing inverse electromagnetic radiation, eddy effect, simultaneous maintaining moderate magnetic loss ability. Besides, the formed interface of ZnFe 2 O 4 /Fe could induce interface polarization relaxation effect at external electromagnetic field, which greatly boosted the effective dielectric loss ability (ε'' E). Meanwhile, the interface polarization intensity was controllable by tuning the weight ratio of Fe. [ABSTRACT FROM AUTHOR]

Graphical abstract Uniform multi-shelled ZnO hollow spheres were synthesized, especially hedgehog-like and triple-shelled ZnO hollow spheres were synthesized for the first time by a simple hydrothermal method capable of controlling the number of internal multishells, which are achieved by controlling the calcination process. Used as anodes for lithium ion batteries, the hedgehog-like ZnO hollow spheres show excellent rate capacity, good cycling performance, and high initial specific capacity. Highlights • Hedgehog-like hollow spheres were synthesized by an easy hydrothermal method. • Uniform multi-shelled ZnO hollow spheres were synthesized. • The ZnO samples show excellent rate capacity, good cycling performance, and high initial specific capacity. Abstract Herein, uniform multi-shelled ZnO hollow spheres were synthesized, especially hedgehog-like and triple-shelled ZnO hollow spheres were synthesized for the first time by a simple hydrothermal method capable of controlling the number of internal multishells, which are achieved by controlling the calcination process. Used as anodes for lithium ion batteries, the hedgehog-like ZnO hollow spheres show excellent rate capacity, good cycling performance, and high initial specific capacity. A superior capacity, up to 109 mAh g−1 with minimal irreversible capacity (i.e. , coulomb efficiency of 99.1%) after 100 cycles is achieved at a current rate of 100 mA g−1, and a capacity of 98.8 mAh g−1 is obtained at a current rate of 1 A g−1. However, a high discharge of 253.6 mA h g−1 for the hedgehog-like ZnO hollow spheres can still be achieved when the current rate is reduced back to 100 mA g−1. [ABSTRACT FROM AUTHOR]

This paper deals with the dynamic stability problem of a tripod parallel robotic wrist by means of monodromy matrix method. This robotic wrist can generate a continuous end-effector rotation in any configuration within its orientation workspace, which allows the manipulator to function as a machine tool head used for a drill point grinder. The system’s linearized equations of motion are established in terms of both lateral and torsional vibrations to analyze the stability problem, resorting to the Floquet theory. As a result, the stable regions of the manipulator are visualized, and the stability charts are constructed on various parameter planes to detect the parametric instabilities and to reveal the effect of the selected pairs of system parameters onto the stability. Critical parameters, such as the rotating speeds of the driving shaft and the actuation stiffness, are identified for the prototyped grinder. [ABSTRACT FROM AUTHOR]

In this study, we used a combination of graphene oxide-based porous carbon (GC) and titanium chloride (TiCl 3 ) to improve the reversible dehydrogenation properties of magnesium hydride (MgH 2 ). Examining the effects of GC and TiCl 3 on the hydrogen storage properties of MgH 2 , the study found GC was a useful additive as confinement medium for promoting the reversible dehydrogenation of MgH 2 . And TiCl 3 was an efficient catalytic dopant. A series of controlled experiments were carried out to optimize the sample preparation method and the addition amount of GC and TiCl 3 . In comparison with the neat MgH 2 system, the MgH 2 /GC-TiCl 3 composite prepared under optimized conditions exhibited enhanced dehydrogenation kinetics and lower dehydrogenation temperature. A combination of phase/microstructure/chemical state analyses has been conducted to gain insight into the promoting effects of GC and TiCl 3 on the reversible dehydrogenation of MgH 2 . Our study found that GC was a useful scaffold material for tailoring the nanophase structure of MgH 2 . And TiCl 3 played an efficient catalytic effect. Therefore, the remarkably improved dehydrogenation properties of MgH 2 should be attributed to the synergetic effects of nanoconfinement and catalysis. [ABSTRACT FROM AUTHOR]

In this research, we provide a facile method to development of band width electromagnetic absorber via loading magnetic quantum dots on the mono-dispersed amorphous carbon sphere. The phenolic resin sphere (RS)/Fe-glycolate has been successfully prepared firstly through thermal-decomposition method. By another high-temperature carbonatization process, the phenolic resin sphere, Fe-glycolate were converted into amorphous sphere and Fe 3 O 4 or Fe quantum dots, respectively. The dielectric loss and electromagnetic absorption properties becomes stronger at elevated carbonatization temperature. This is can be explained that carbon sphere at high temperature can gradual reduce the Fe 3 O 4 quantum dots to Fe, leading to the boosted polarization and conductive loss ability. Besides, the reduction degree is controllable by adjusting the carbonatization carbon sphere/Fe-Fe 3 O 4 obtained at 700 °C shows excellent electromagnetic absorption properties which the effective electromagnetic absorption region covers 5.8 GHz with a coating thickness of 1.5 mm. To better understand of the absorption mechanism, the contributions of carbon sphere, Fe, Fe 3 O 4 have been discussed in depth. [ABSTRACT FROM AUTHOR]

This paper deals with the optimal structural design of a Biglide parallel grinder for drill grinding. A pair of spatial modules is adopted to replace the conventional parallelogram to enhance the out-of-plane stiffness of the latter. A multi-objective design optimization problem is formulated, of which the stiffness, motion/force transmission, and work space are taken into consideration. The Pareto front of the optimization problem is obtained to provide the optimum design of the Biglide machine, and a scatter matrix is visualized to reveal the influence of the link dimensions to the performance. The selected design from the Pareto front guarantees the requirement on the elastostatic performance in the grinding process with increased dexterous workspace size. [ABSTRACT FROM AUTHOR]

This paper deals with the stiffness modeling, analysis and comparison of a Biglide parallel grinder with two alternative modular parallelograms. It turns out that the Cartesian stiffness matrix of the manipulator has the property that it can be decoupled into two homogeneous matrices, corresponding to the translational and rotational aspects, through which the principal stiffnesses and the associated directions are identified by means of the eigenvalue problem, allowing the evaluation of the translational and rotational stiffness of the manipulator either at a given pose or the overall workspace. The stiffness comparison of the two alternative Biglide machines reveals the (dis)advantages of the two different spatial modular parallelograms. [ABSTRACT FROM AUTHOR]

This paper deals with the architecture optimization of a parallel Schönflies-motion robot admitting a rectangular workspace, which allows to utilize the shop-floor space efficiently for flexible pick-and-place applications. In this work, parametric models including the transmission quality, elasto-statics and dynamics are established and further used in the integrated architectural design optimization. By taking the design requirements and pick-and-place trajectory into consideration, the kinematic and dynamic performances of the robot are optimized with prescribed workspace based on a multi-objective optimization approach. The Pareto-front is obtained, which provides optimal solutions to the robot design. Robot prototyping work based on the optimal results is described. [ABSTRACT FROM AUTHOR]

This paper presents a comparative study of asymmetrical spherical parallel manipulators with respect to motion/force transmission and stiffness. The manipulators adopt a center shaft to both generate a decoupled unlimited-torsion motion and support the mobile platform for high positioning accuracy, where the difference lies in the rotationally/linearly actuated limbs in-parallel. The transmission indices are defined based on the virtual coefficient between the transmission wrench and twist screws for design analysis. Comparison of the manipulators is carried out based on a multi-objective optimization approach, which aims to maximize the workspace of high transmissibility and stiffness over a regular workspace. Performance isocontours are visualized to highlight the advantages/drawbacks among the manipulator counterparts. [ABSTRACT FROM AUTHOR]

• Novel absorber of unique biconical carbon frame decorated with CoFe 2 O 4 and (Fe, Ni) was prepared. • The geometrical morphology and size of decorated NPs can be simply regulated by controlling the pyrolysis temperature. • The broadband effective absorption bandwidth of 6.55 GHz would be achieved for only 1.87 mm thickness. The typical environment pollution of superfluous microwave radiation has become an urgent problem to be solved at current stage. Herein, a new-style composite of unique biconical carbon framework decorated with CoFe 2 O 4 and (Fe,Ni) nanoparticles was obtained by the co-hydrothermal and pyrolysis route. With the temperature-depended adjustability in microstructure, the composite calcined under 600℃ possesses the largest length–width ratio of amorphous carbon skeleton and the smallest median diameter of decorated NPs among all the samples. This could promote the interface polarization ability and geometrical anisotropy for conductivity, together with N-doping induced dipole polarization, the composite represents excellent dielectric loss capacity for microwave absorption. Moreover, the eddy current effect of magnetic alloy and natural resonance associated with ferrite also assist to this wastage. Under the optimal impedance matching, this composite owns maximal RL of −34.3 dB at 12.92 GHz for 2.0 mm with its broadest effective absorption bandwidth of 6.55 GHz at only 1.87 mm, covering the whole K u and partial X bands. This work offers a novel microwave absorber with appropriate absorbing intensity and excellent bandwidth for practical usage. [ABSTRACT FROM AUTHOR]

• A new framework of robotic mechanism topology is presented. • The framework includes two concepts, three formulas and systemic synthesis methods. • Three formulas reveal mapping relation among the topology structure, POC and DOF. • Four type synthesis methods are grouped into algebraic and intrinsic geometry method. • The framework is helpful to compare different theories and develop PM topology. In this work, a new basic framework of robotic mechanism topology is proposed, which includes: ① two important concepts (i.e., topological structure and kinematic characteristics), ② three basic formulas (i.e., POC equation of serial mechanisms, POC equation of parallel mechanisms (PMs), and DOF formula) and ③ topological structure synthesis methods of PMs. Based upon this framework, literature review and comparative study of four original theories for topological structure synthesis of PMs (i.e., screw theory, velocity space, subgroup and POC set) are carried out. Moreover, it is found that these four theories and their computable methods (linear operation, nonlinear symbolic operation and linear symbolic operation) originate from different definitions and their mathematical representations of the two concepts. These basic formulas accounting for mechanism topology are derived based on the two concepts, which reveal the mapping relationship among topological structures, POCs and DOF of mechanisms. Further, these four theories are grouped into two categories: ① the algebraic methods related to the fixed coordinate system for screw theory, velocity space and subgroup; ② the intrinsic geometry method independent of the fixed coordinate system for POC set. [ABSTRACT FROM AUTHOR]

Uniform multishelled NiO, Co3O4, ZnO, and Au@NiO hollow spheres were synthesized (NiO and Co3O4 hollow spheres for the first time) by a simple shell-by-shell self-assembly allowing for tuning of the the size, thickness and shell numbers by controlling the heat treatment, glucose/metal salt molar ratio, and hydrothermal reaction time. These findings further the development of synthetic methodologies for multishelled hollow structures and could open up new opportunities for deeper understanding of the mechanisms of shell-by-shell self-assembly. Moreover, the double-shelled NiO hollow sphere exhibits a higher photocatalytic activity for degradation of methyl orange than its morphological counterparts. [ABSTRACT FROM AUTHOR]

Nanostructured 3D CeO 2 have been synthesized by using PEG 2000 assisted simple hydrothermal technique. The impact of this novel approach on the structure, morphology, spectroscopy, complex permittivity and permeability was discussed. CeO 2 was studied by employing X-ray diffraction (XRD), Raman spectra, field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TG) and vector network analyzer. It can be seen that the microspheres of 1–3 μm in diameter were prepared at 600 °C with a mole ratio of 2:1, while the decreasing concentration of PEG-2000 resulted in the appearance of dim side-shape geometry. Obviously, the morphology of the synthesized CeO 2 gradually changed from sphere with relatively smooth to irregular side-shape annealed at 600 °C with the increase of mole ratio for reactants. The electromagnetic (EM) wave absorption properties of the synthesized CeO 2 were investigated over the range from 2 to 16 GHz, and minimum reflection loss (RL) with −19.3 dB was observed at 15.8 GHz with the thickness of 2.0 mm. This phenomenon may be attributed to both intrinsic characteristic of CeO 2 and preparation with the function of PEG-2000. [ABSTRACT FROM AUTHOR]

We reported a facile approach to prepare peculiar porous α-Fe 2 O 3 , γ-Fe 2 O 3 and Fe 3 O 4 nanospheres by combining a facile hydrothermal route with a calcination process in Ar or H 2 atmosphere. The synthesized monodisperse porous α-Fe 2 O 3 nanospheres with uniform average diameters of ~ 60 nm in fact contained randomly distributed pores. A close view further revealed that there are two types of pores, one is large mesopores (ca. 15–20 nm) in the center, and the other is small mesopores (ca. < 10 nm) in the outside. After calcining in Ar or H 2 , the obtained α-Fe 2 O 3 , γ-Fe 2 O 3 and Fe 3 O 4 nanospheres preserved the similar morphology and particle size as the uncalcined α-Fe 2 O 3 nanospheres, indicating the as-prepared α-Fe 2 O 3 nanospheres are stable under Ar and H 2 -annealing heat treatment. Comparing with all the paraffin composites, it was found that the porous α-Fe 2 O 3 nanosphere/paraffin composites exhibit a higher permittivity level. A minimum reflection loss (RL) of − 25 dB was observed at ~ 13 GHz for the porous α-Fe 2 O 3 nanosphere/paraffin composites with a thickness of 3.5 mm, and the effective absorption frequency (RL < − 10 dB) ranged from 9.9 to 15.1 GHz. The composites exhibited better absorption properties than the magnetic porous γ-Fe 2 O 3 and Fe 3 O 4 nanosphere/paraffin composites. [ABSTRACT FROM AUTHOR]

Core-shell structured γ -Fe 2 O 3 @C nanorod-carbon sphere composites have been synthesized via a facile hydrothermal method employing FeCl 3 ·6H 2 O as the iron source and d -glucose as the carbon source. The core–shell structured γ -Fe 2 O 3 @C nanorods possess a uniform size with ∼500–800 nm in length, the carbon shell's thickness is ∼3–10 nm, and the γ -Fe 2 O 3 core is homogeneously coated by amorphous carbon layer. The measured electromagnetic (EM) parameters show that its maximum reflection loss (RL) can reach −8.11 dB at 3.92 GHz. This is mainly attributed to the multiple-interfacial polarization among the core–shell structured γ -Fe 2 O 3 @C nanorod-carbon sphere composites. The core–shell structured γ -Fe 2 O 3 @C nanorod-carbon sphere composites can be a promising candidate for lightweight microwave materials. [ABSTRACT FROM AUTHOR]

This paper presents an asymmetrical spherical parallel manipulator and its transmissibility analysis. This manipulator contains a center shaft to both generate a decoupled unlimited-torsion motion and support the mobile platform for high positioning accuracy. This work addresses the transmission analysis and optimal design of the proposed manipulator based on its kinematic analysis. The input and output transmission indices of the manipulator are defined for its optimum design based on the virtual coefficient between the transmission wrenches and twist screws. The sets of optimal parameters are identified and the distribution of the transmission index is visualized. Moreover, a comparative study regarding to the performances with the symmetrical spherical parallel manipulators is conducted and the comparison shows the advantages of the proposed manipulator with respect to its spherical parallel manipulator counterparts. [ABSTRACT FROM AUTHOR]

Pollution of agricultural ecosystems is due to the excessive use of mineral fertilizers and mass discharge of livestock manure. Therefore, there is a need for disposing manure safely, for instance by transforming manure into valuable compost. Traditional composting is, however, time-consuming with considerable nutrient losses. Vermicomposting is an alternative method, but so far, there are few quantitative evaluations of vermicomposting. We therefore compared vermicomposting and traditional composting of cattle manure with maize. Our results show that the amount of nutrients from vermicomposting is lower than that from traditional composting. Nonetheless, vermicomposting yielded 2172.0 kg of earthworms per hectare, which provided an additional income of US$4008.1 to farmers. Moreover, vermicomposting increased aboveground biomass by 7.7 % and maize grain yield by 18.3 %. The global output of vermicomposting was thus higher by 304 % due to higher grain yield and earthworm income. [ABSTRACT FROM AUTHOR]

Urchin-like ZnO hollow spheres were synthesized by a simple hydrothermal method and their electromagnetic and microwave absorbing properties were investigated. The enlarged SEM image shows that as-prepared ZnO precursor is composed of randomly close-packed porous nanosheets. On the contrary, well-crystallized ZnO spheres are obtained after calcination. The TEM images provide further insight into the detailed structure, showing the typically urchin-like and hollow morphology of ZnO calcined at 500 °C. The SAED pattern clearly demonstrates the single-crystalline feature of urchin-like ZnO hollow spheres. It can be found that the urchin-like ZnO calcined at 500 °C exhibit relatively higher EM wave absorption properties than others. The maximum RL is up to −20 dB at 14.3 GHz and the EM wave absorption shows dual peaks with increasing thickness. [ABSTRACT FROM AUTHOR]

In this paper, we report a novel strategy for the synthesis of Prussian Blue microcubes via hydrothermal conditions by using K 3 [Fe(CN) 6 ] and glucose for the first time, and then hollow Fe 2 O 3 microboxes have been successfully fabricated by calcination from a Prussian Blue microcube precursors. The phase structures and morphologies were studied using X-ray powder diffraction (XRD), scanning electronic microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and high resolution transmission electron microscopy (HRTEM) with selected area electron diffraction (SAED). The results depict that highly pure and single crystalline monodisperse hollow Fe 2 O 3 microboxes are successfully obtained, which have a diameter ranging from 3 to 5 μm. The optical properties of the Prussian Blue microcubes and hollow Fe 2 O 3 microboxes were observed by photoluminescence spectra. [ABSTRACT FROM AUTHOR]

We reported the preparation of C@Ni–NiO core–shell hybrid solid spheres or multi-shelled NiO hollow spheres by combining a facile hydrothermal route with a calcination process in H 2 or air atmosphere, respectively. The synthesized C@Ni–NiO core–shell solid spheres with diameters of approximately 2–6 μm were in fact built from dense NiO nanoparticles coated by random two-dimensional metal Ni nanosheets without any visible pores. The multi-shelled NiO hollow spheres were built from particle-like ligaments and there are a lot of pores with size of several nanometers on the surface. Combined Raman spectra with X-ray photoelectron spectra (XPS), it suggested that the defects in the samples play a limited role in the dielectric loss. Compared with the other samples, the permeability of the samples calcined in H 2 and air was increased slightly and the natural resonance frequency shifted to higher frequency (7, 11 and 14 GHz, respectively), leading to an enhancement of microwave absorption property. For the sample calcined in H 2 , an optimal reflection loss less than − 10 was obtained at 7 GHz with a matching thickness of 5.0 mm. Our study demonstrated the potential application of C@Ni–NiO core–shell hybrid solid sphere or multi-shelled NiO hollow sphere as a more efficient electromagnetic (EM) wave absorber. [ABSTRACT FROM AUTHOR]

This paper deals with the dynamic modeling and design optimization of a three Degree-of-Freedom spherical parallel manipulator. Using the method of Lagrange multipliers, the equations of motion of the manipulator are derived by considering its motion characteristics, namely, all the components rotating about the center of rotation. Using the derived dynamic model, a multiobjective optimization problem is formulated to optimize the structural and geometric parameters of the spherical parallel manipulator. The proposed approach is illustrated with the design optimization of an unlimited-roll spherical parallel manipulator with a main objective to minimize the mechanism mass in order to enhance both kinematic and dynamic performances. [ABSTRACT FROM AUTHOR]

The two-dimensional (2D) transition metal carbide Ti3C2Tx MXene is a potential candidate for efficient electromagnetic wave absorbers due to its excellent intrinsic conductivity and structural machinability. However, Ti3C2Tx MXene also has some problems (such as self-stacking and single loss mechanism) that limit its practical electromagnetic wave absorption. Based on the electromagnetic wave absorption mechanism, electromagnetic responsiveness of absorbers can be modulated by designing the composition and structure. Herein, a 1D/2D Co/Co9S8/Ti3C2Tx composite has been synthesized by assembling 2D Ti3C2Tx MXene with the designed 1D magnetic structure. The 1D Co/Co9S8 was designed as a core-sheath structure that avoids magnetic agglomeration, and the assembly with 2D Ti3C2Tx sheets alleviates the self-stacking problem of Ti3C2Tx MXene sheets. More importantly, the magnetic component enriches the electromagnetic wave dissipation mechanism, and the multiple heterojunction surfaces provide strong polarization loss capability for the Ti3C2Tx MXene-based absorber. Benefiting from the unique structure and dielectric-magnetic synergistic loss, the Co/Co9S8/Ti3C2Tx composite shows an effective absorption bandwidth of 5.36 GHz (10.08–15.44 GHz) at 2.1 mm and the optimal RLmin value of −52.02 dB at 1.8 mm. This work provides an innovative idea for the design of effective Ti3C2Tx MXene-based absorbers. [ABSTRACT FROM AUTHOR]

Abstract: Spherical parallel manipulators (SPMs) with revolute joints work under the condition that all joint axes intersect at the manipulator center, where the mobile platform (MP) center is coincident with the center of the base platform. The center of each platform is the point of concurrence of the axes of the three revolute joints attached to the platform. When limb flexibility is considered, however, the MP center will shift away from the base platform center, which consequently influences the manipulator performance, e.g., its orientation accuracy. In this work, the stiffness of SPMs is analyzed, with focus on the MP center shift. The stiffness is modeled by adopting the virtual-spring method. Castigliano's theorem is used to calculate the limb deflection. The model is validated via FE analysis. Examples are included to show the center shift of SPMs with different designs. [Copyright &y& Elsevier]

Highlights: [•] The isoconversional method was used to describe the curing kinetics parameters of the modified systems. [•] The mechanical and thermal properties of the copolymers were found to be a higher than that of BOZ/BMI system. [•] The moisture absorption of the blends was found to be lower than that of the BOZ/BMI system. [Copyright &y& Elsevier]

In this paper, we reported the preparation of the bismaleimide-triazine/epoxy interpenetrating polymer networks using 4,4′-bismaleimidodiphenymethane (BMI), bisphenol A dicyanate (BADCy) and 4,5-epoxycyclohexane 1,2-dicarboxylic acid dilycidyl (TDE-85) epoxy resin. The non-isothermal curing kinetics of TDE-85/BMI/BADCy copolymer was studied by the differential scanning calorimetry (DSC) at various heating rates. Kissinger equation and Ozawa equation were used to describe the apparent activation energy of the modified system. Compared to unmodified BMI/BADCy resins, the TDE-85/BMI/BADCy copolymer exhibited excellent mechanical properties and stable thermal properties when the content of TDE-85 epoxy resin was 20wt%. The dielectric properties of TDE-85/BMI/BADCy copolymer such as dielectric constant and dielectric dissipation factor remained the good stability over a wide frequency from 10MHz to 60MHz. [Copyright &y& Elsevier]

Recurrent atrial arrhythmias (RAAs) following posterior left atrial isolation (PLAI) for atrial fibrillation are common and are associated with reconnection of the PLA and pulmonary veins. We aimed to show that P-wave duration (PWD) and P-wave area under the curve (PWAUC) changes in patients undergoing PLAI can be measured using signal-averaged electrocardiogram (SAECG), and that reversal of these changes in patients with RAAs can be used to noninvasively detect reconnection. SAECG recordings before and after PLAI in 52 patients were analyzed for changes in PWD and PWAUC and also in 26 of these patients who had a repeat procedure for RAA. PWD and PWAUC reduced significantly in most leads following PLAI (mean 104 ± 11 ms to 93 ± 15 ms [P < 0.001] and 3.53 ± 1.23 microvolt seconds (μVs) to 2.87 ± 1.23 μVs [P = 0.001], respectively). Reconnection was observed in 20 of 26 patients at the repeat procedure. Compared to after the first procedure, reconnected patients had increased PWD and PWAUC (e.g., the increase in V4 was 14.1 ± 20.9 ms [P = 0.01] and 0.98 ± 1.17 μVs [P = 003], respectively) at the repeat procedure, while nonreconnected patients had decreased PWD and PWAUC (in V4, it was decreased by 11.5 ± 7.0 ms [P = 0.05] and 0.97 ± 0.33 μVs [P = 0.001]). A change in lead V4 PWAUC > −0.29 μVs for detecting reconnection had a sensitivity of 94% and specificity of 100% (receiver operator characteristic area under the curve 0.97, P = 0.005). PLAI reduces PWD and PWAUC while reconnection increases them both. SAECG may be able to detect reconnection of the PLA noninvasively. (PACE 2010; 1324-1334) [ABSTRACT FROM AUTHOR]

[Display omitted] • Bismuth (Bi) nanotube architecture was prepared by in situ electrochemical reduction. • This Bi nanotube architecture exhibited excellent selectivity and durability for CO 2 RR. • The step for OCHO* intermediate generation preferentially happened at edge sites. • The rich edge sites from unique nanostructure boosted the formate production. Electrochemical conversion of CO 2 into valuable chemical fuels is a promising technology for addressing climate change and energy issues, but the progress of it has been hampered by the lack of selective and stable electrocatalysts. In this work, metallic bismuth (Bi) architecture electrocatalyst was synthesized by in situ electrochemical reduction of two-dimensional (2D) bismuth oxyiodide (BiOI) architecture, which was composed by one-dimensional (1D) BiOI nanotubes using structural assembly method. Owning to the enhanced active sites from this unique morphology, this Bi electrocatalyst exhibited high activity, excellent selectivity (Formate Faradaic efficiency is 97.1% with a partial current density of 31.1 mA cm−2 at an overpotential of only 790 mV), and excellent durability (65 h at a current density of 10 mA cm−2) for CO 2 reduction reaction (CO 2 RR). For deeply understanding the factors governing the activity of this Bi catalyst, density functional theory (DFT) computations are employed, and the OCHO* intermediate preferentially adsorbs on the edge sites. When the rich edges sites were covered by oleylamine molecules, this step was impeded, and formate production obviously decreased. This work shows the importance of metallic Bi with unique nanostructure for catalyzing CO 2 RR towards formate with high efficiency and selectivity. [ABSTRACT FROM AUTHOR]

• A parallel PnP robot with efficient utilization of shop-floor space and high rotational capability. • FSMVSC control variables are optimized for robot dynamics enhancement. • Experimental results validate and show the effectiveness of control design. • Tradeoff between acceptable computational cost and positioning accuracies. This paper presents the analysis and experimental evaluation of robot dynamics and control for a four-limb parallel Schönflies-motion generator dedicating to fast pick-and-place operations, with a different topological architecture from its counterparts for efficient use of shop-floor space. The concise equation of motion is built with principle of virtual work to characterize the robot dynamics, which is integrated into the model-based control design. Fuzzy sliding mode variable structure control is adopted for the design of control scheme, aiming at buffeting suppression of the actuated joints and minimization of pose errors of robot end-effector. Numerical simulations are carried out along a trajectory of an industrial standard testing cycle to evaluate the performance, which is validated experientially by observing the joint dynamics. The results show the effectiveness of the developed dynamic control scheme for fast parallel pick-and-place robots. [ABSTRACT FROM AUTHOR]

[Display omitted] Hydrophilic-hydrophobic microphase separation is an important mechanism to promote aqueous polymer self-assembly. However, it is rarely used in the construction of magneto-dielectric absorbers in the interdisciplinary research involving organic polymer and inorganic hybrid material. Herein, a novel metal-coordination-driven self-assembly strategy is proposed for fabricating organic–inorganic composite co-assemblies by combining resorcinol–formaldehyde resin as carbon precursor and iron-containing polymer self-assemblies as soft template. Co-assemblies are then transformed into porous iron/carbon (Fe/C) composites with spherical Fe nanoparticles and micro-mesopores that form in graphited carbon matrix through high-temperature pyrolysis. The minimum reflection loss of Fe/C-800 composite in paraffin matrix with 10% filler loading can reach −57.8 dB, while the effective absorption bandwidth of 5.3 GHz can cover the whole X band. It is considered that the co-assemblies-derived microstructure and magneto-dielectric composition contribute to the multiple reflection, polarization loss, conductive loss, ferromagnetic resonance and eddy current loss for high-efficiency electromagnetic wave absorption. In general, this work opens up new prospects for designing and preparing high-performance magneto-dielectric absorbers via a novel metal-coordination-driven self-assembly strategy. [ABSTRACT FROM AUTHOR]

In order to eliminate the hazards induced by electromagnetic pollution, the preparation of microwave absorbing composite incorporating biomass-derived porous carbon with efficient magnetic component has been recognized as a valid route. Herein, a serious of Co/Ni NPs decorated porous carbon sphere were successfully prepared via a combined method of activation, hydrothermal and annealing process. By controlling the addition amount of activator and the concentration of precursor, the appropriate morphology and impedance matching can be obtained in the as-prepared hybrid. Thus, the super-wide EAB of S4 can reach 7.30 GHz for only 2.3 mm thickness, and its maximum RL is −76.54 dB at 12.23 GHz with a thickness of 2.5 mm. This outstanding microwave absorption properties could be attributed to the synergistic effect of magnetic and dielectric loss under decent impedance matching condition, which includes the primary nature and exchange resonance, destructive interference, together with multiple reflection and scattering effect, and the subordinate effect of dipole and interface polarization loss. This work offers a novel route to prepare biomass-derived porous carbon loaded with magnetic NPs for strong and broadband electromagnetic absorption. [Display omitted] [ABSTRACT FROM AUTHOR]

The electrospinning technique was employed to prepare the La 0.5 Sr 0.5 Mn 0.875 Zn 0.125 O 3-δ (LSMZn) cathode for proton-conducting solid oxide fuel cells (H–SOFCs). Although the fiber structure can be obtained with the electrospinning technique for the LSMZn precursor, the fiber structure disappeared after the calcination procedure, leading to the formation of fine LSMZn nano-powders. It was found that the electrospun LSMZn can reach a pure phase after firing at 1100 °C, whereas the traditional sol-gel prepared LSMZn required a calcination temperature of 1150 °C. Furthermore, the electrospun LSMZn had a smaller particle size and richer oxygen vacancy than the traditional sol-gel LSMZn. First-principles calculations indicated that the oxygen vacancy-rich surface promoted the cathode reaction. The H–SOFC using the single-phase electrospun LSMZn generated a power density of 1122 mW cm−2 at 700 °C. The performance was not only larger than the sol-gel LSMZn cell reported in this study but also larger than previous H–SOFCs using the single-phase Mn-based cathodes, suggesting the electrospinning technique was an effective method to produce high-performing cathodes for H–SOFCs. [ABSTRACT FROM AUTHOR]

As typical magnetic materials, ferrites and their composites play dominant roles in the design of high-performance electromagnetic wave (EW) absorber. Solvent thermal method is the most popular route for synthesizing ferrites, while systematical comparison research about the influence of reaction solvents of solvent thermal process on ferrite based material's EW absorption performance has rarely been carried out. Thus in this work, we adopted cotton fabric as raw material, and synthesized two kinds of zinc ferrite decorated hollow carbon cloth (CC@ZnFe 2 O 4) composites through solvent thermal reaction where deionized water and ethylene glycol was adopted as reaction solvents, respectively. After comprehensive and detailed comparison of the structures and performances of these two ferrite composites, the CC@ZnFe 2 O 4 synthesized in deionized water phase possesses an ideal optimal absorption efficiency for EW, that is the minimum reflection loss (RL min) of −46 dB, while the effective absorption bandwidth of CC@ZnFe 2 O 4 composites synthesized in ethylene glycol phase is wider (4.9 GHz). The synergistic effect of impedance matching, interface polarization, magnetic resonance, and multiple reflections co-determined the ideal EW absorption performances of these two samples. The research can not only provide new guidance for the secondary utilization of waste textiles, but also become an important reference for the preparation of ferrite based high-performance EW absorbers through solvent thermal method. [Display omitted] [ABSTRACT FROM AUTHOR]

Polarization at interfaces is an important loss mechanism for electromagnetic wave (EMW) attenuation, though the motion behavior of carriers in interfaces composed of different types of conductors has yet to be investigated. Tuning the phase structure of transition metal dichalcogenides (TMDs) MS2 (M = Mo, V, W) by organics small molecule intercalation to achieve the modulation of interfacial types is an effective strategy, where 1T‐MS2 exhibits metallic properties and 2H‐MS2 has semiconducting properties. To exclude the contribution of the intrinsic properties of TMDs materials, three TMDs (MoS2, VS2, and WS2), which also possess phase transitions, are investigated. Among them, the 1T‐MS2 composite exhibits excellent EMW absorption performance under the synergistic effect of interfacial polarization and conduction loss. 1T‐MoS2/MOF‐A exhibits the best EMW absorption performance with an RLmin of −61.07 dB at a thickness of 3.0 mm and an EAB of 7.2 GHz at 2.3 mm. The effectiveness of the modulation of the interfacial polarization using 1T‐phase and 2H‐phase MS2 is demonstrated, which is important for the analysis of the carrier motion behavior during the interfacial loss. [ABSTRACT FROM AUTHOR]

• A four-limb parallel Schönflies motion generator with full-circle end-effector rotation. • Singularity loci are identified graphically and numerically. • A super-ellipsoidal workspace free of singularity suitable for pick-and-place application. • Operation modes are identified for singularity avoidance. This paper presents a four-limb parallel Schönflies motion generator for the pick-and-place application, whose end-effector is composed of a planetary gear train as the amplification mechanism to realize the full-circle rotation. The kinematic aspects, including the workspace, dexterity and singularity, are analyzed and evaluated. The singular configurations and the singularity loci are identified both graphically and numerically, which shows that the singular configurations of the manipulator can be avoided by keeping all the limbs working in a prescribed working mode together with the end-effector rotation in a clockwise direction from the neutral orientation. Moreover, the dexterity evaluation is carried out to depict the workspace quality and dexterous working envelope. It turns out that the proposed robot admits a super-ellipsoidal workspace with the full-circle rotation of the end-effector, suitable for pick-and-place operations. Finally, robot dynamics is considered to select the actuators. [ABSTRACT FROM AUTHOR]

Highlights: Heterogeneous interface engineering is designed by electrospinning. The introduction of Co3SnC0.7 nanoparticles increased the loss mechanism. Enhanced electromagnetic loss and improved impedance matching are achieved. The absorbers exhibit high-efficient electromagnetic wave absorption performance. Application of novel radio technologies and equipment inevitably leads to electromagnetic pollution. One-dimensional polymer-based composite membrane structures have been shown to be an effective strategy to obtain high-performance microwave absorbers. Herein, we reported a one-dimensional N-doped carbon nanofibers material which encapsulated the hollow Co3SnC0.7 nanocubes in the fiber lumen by electrospinning. Space charge stacking formed between nanoparticles can be channeled by longitudinal fibrous structures. The dielectric constant of the fibers is highly related to the carbonization temperature, and the great impedance matching can be achieved by synergetic effect between Co3SnC0.7 and carbon network. At 800 °C, the necklace-like Co3SnC0.7/CNF with 5% low load achieves an excellent RL value of − 51.2 dB at 2.3 mm and the effective absorption bandwidth of 7.44 GHz with matching thickness of 2.5 mm. The multiple electromagnetic wave (EMW) reflections and interfacial polarization between the fibers and the fibers internal contribute a major effect to attenuating the EMW. These strategies for regulating electromagnetic performance can be expanded to other electromagnetic functional materials which facilitate the development of emerging absorbers. [ABSTRACT FROM AUTHOR]

[Display omitted] • The proper impedance enables the material to efficiently allow the EM waves into its interior. • Aggregation state of PANI can influence the conductivity, dielectric and its wave absorption. • MS@PANI achieves ultra-low density and effective absorption of whole X-band EM waves. In the field of electromagnetic (EM) wave absorption, intrinsic conductive polymers with conjugated long-chain structures, such as polyaniline (PANI) and polypyrrole (PPy), have gained widespread use due to their remarkable electrical conductivity and loss ability. However, current research in this area is limited to macroscopic descriptions of the absorption properties of these materials and the contribution of various components to the absorption effect. There has been insufficient exploration of the impact mechanisms of polymer aggregation states on the material's absorption performance and mechanism. To address this, a series of flexible PANI sponge absorbers with different molecular weights and aggregation states were prepared. By carefully controlling the crystallinity and other aggregation characteristics of PANI through the adjustment of its preparation conditions, we were able to influence its electrical conductivity and electromagnetic parameters, thereby achieving control over the material's absorption properties. The resulting PANI sponge absorbers exhibited an effective absorption bandwidth (EAB) that covered the entire X-band at a thickness of 3.2 mm. This study comprehensively explores the absorption mechanisms of conductive polymer absorbers, starting from the microstructure of PANI, and providing a more complete theoretical support for the research and promotion of polymer absorbers. [ABSTRACT FROM AUTHOR]

Highlights: The hierarchical porous structure is regulated by various species of PVP to achieve impedance matching. Interfacial engineering boosts conductivity and constructs a multiband (C, X, Ku) tunable electromagnetic wave absorber. Hierarchical porous molybdenum selenide/epoxy coating exhibits marine anticorrosion capability. Electromagnetic wave (EMW) absorbing materials have an irreplaceable position in the field of military stealth as well as in the field of electromagnetic pollution control. And in order to cope with the complex electromagnetic environment, the design of multifunctional and multiband high efficiency EMW absorbers remains a tremendous challenge. In this work, we designed a three-dimensional porous structure via the salt melt synthesis strategy to optimize the impedance matching of the absorber. Also, through interfacial engineering, a molybdenum carbide transition layer was introduced between the molybdenum selenide nanoparticles and the three-dimensional porous carbon matrix to improve the absorption behavior of the absorber. The analysis indicates that the number and components of the heterogeneous interfaces have a significant impact on the EMW absorption performance of the absorber due to mechanisms such as interfacial polarization and conduction loss introduced by interfacial engineering. Wherein, the prepared MoSe2/MoC/PNC composites showed excellent EMW absorption performance in C, X, and Ku bands, especially exhibiting a reflection loss of − 59.09 dB and an effective absorption bandwidth of 6.96 GHz at 1.9 mm. The coordination between structure and components endows the absorber with strong absorption, broad bandwidth, thin thickness, and multi-frequency absorption characteristics. Remarkably, it can effectively reinforce the marine anticorrosion property of the epoxy resin coating on Q235 steel substrate. This study contributes to a deeper understanding of the relationship between interfacial engineering and the performance of EMW absorbers, and provides a reference for the design of multifunctional, multiband EMW absorption materials. [ABSTRACT FROM AUTHOR]

Biogas projects have been promoted by the Chinese government in rural areas for several decades. However, these projects have proceeded slowly under the lack of biogas production technology. A circular agricultural experiment in combination with a local biogas promotion project was carried out in Jiangjiazhuang, a typical agricultural village in China, from 2008 to 2015. Agricultural production proceeded in an agricultural loop: “Crops → Grains/crop residues → Human/cattle → Human/cattle excreta → Biogas digester → Biogas/biogas residues → Domestic fuels/organic fertilizers → Crops.” The abundant crop residues were used as cattle forage to turn the biomass energy into human-edible food. Human/cattle dejecta was used as the substrate to produce biogas for livelihood energy. Biogas digester residues were used as organic fertilizers after composting to improve soil quality and crop yield. The results showed that the proportion of crop residues used for cattle forage increased from 1.3% in 2008 to 86.2% in 2015, while cattle population increased from 3 to 198. The proportion of biogas in total household energy increased from 1.1% in 2008 to 62.3% in 2015. Soil organic carbon increased under organic fertilizer application from 83.8 Mg C hm−2 to 213.5 Mg C hm−2. Our findings demonstrate that the promotion of circular agriculture may effectively enhance the utilization rate of biomass energy (crop residues) and reduce the consumption potential of fossil energy over 50%. Circular agriculture is a sustainable agricultural system that could improve the environmental conditions in rural areas. [ABSTRACT FROM AUTHOR]

• A novel MoS 2 @polypyrrole@Fe 3 O 4 composite was skillfully synthesized. • There was no any separation procedure during the synthesis process. • The Fe2+ was successively utilized to prepare the Ppy and Fe 3 O 4. • The composite performs excellent EM wave absorbing performance. The MoS 2 @polypyrrole@Fe 3 O 4 composite was skillfully synthesized via a novel one pot method. No any separation step during the synthesis process, and the Fe2+ was successively utilized to prepare the Ppy and Fe 3 O 4 , which can achieve a high utilization of raw materials. The characterization about microstructure, crystal form, elemental composition and surface functional groups verify the structure of MoS 2 @polypyrrole@Fe 3 O 4. Its hysteresis loop indicates that the composite performs typical soft magnetism behavior, with a magnetic saturation value of 20.3 emu.g−1, which is helpful to improve the magnetic loss for EM wave absorbing. The reflection loss curve suggested that the composite exhibits superior EM wave absorption performance, with a minimum reflection loss value of –32 dB at the specimen thickness of just 2.0 mm due to the fair electromagnetic matching, interface polarization and interface relaxation. In addition, the one pot method used in this work can promisingly be applied to prepare other similar composites such as carbon fiber@polypyrrole@Fe 3 O 4 , graphene@polypyrrole@Fe 3 O 4. [ABSTRACT FROM AUTHOR]

• FeCo-LDO/raspberry-like carbon with hierarchical structure were synthesized. • The structure of LDO and interface in LDO/RCs result in interfacial polarization. • The effective bandwidth is up to 7.4 GHz with thin thickness of 2.2 mm. • The use of positively charged properties to prepare composites is an attempt. Transition metal compositions (Fe, Co and Ni) have always been promising candidates for electromagnetic wave (EMW) absorbers. In this study, the FeCo layered double hydroxide (LDH) supported on raspberry-like carbon spheres (RCs) was synthesized by a simple hydrothermal method and the spontaneous electrostatic self-assembly process. The surface FeCo-LDH is then transformed into FeCo layered double oxide (LDO) with different compositions after calcination treatment (650 °C and 700 °C), forming a typical hierarchical structure. The sample calcined at 700 °C exhibited an ultra-wide effective absorption bandwidth (f e) (RL < −10 dB) of 7.4 GHz (from 10.6 to 18.0 GHz) at the matched thickness of 2.2 mm. The remarkable EM wave absorption properties are attributed to the strong interface polarization due to the various phase boundaries in LDO shell as well as sufficient heterointerfaces between LDO shell and RCs. It should be emphasized that LDH is rarely used for EMW absorption, and the use of LDH positively charged characteristics to fabricate hierarchical materials is a meaningful attempt and confirms the potential of LDH in EMW absorbing materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • The multiscale core–shell structure Ni-MOF@N C with heterogeneous interfaces were constructed. • The optimal RL of Ni-MOF@N C 500 is −69.6 dB and the widest effective absorption bandwidth is 6.8 GHz. • The synergistic effect of N -doped carbon shell dielectric loss and Ni magnetic loss improves impedance matching. The design of metal–organic frameworks (MOF) derived composites with multiple loss mechanisms and multi-scale micro/nano structures is an important research direction of microwave absorbing materials. Herein, multi-scale bayberry-like Ni-MOF@ N -doped carbon composites (Ni-MOF@N C) are obtained by a MOF assisted strategy. By utilizing the special structure of MOF and regulating its composition, the effective improvement of Ni-MOF@N C's microwave absorption performance has been achieved. The nanostructure on the surface of core–shell Ni-MOF@N C can be regulated and N doping on carbon skeleton by adjusting the annealing temperature. The optimal reflection loss of Ni-MOF@N C is −69.6 dB at 3 mm, and the widest effective absorption bandwidth is 6.8 GHz. This excellent performance can be attributed to the strong interface polarization caused by multiple core–shell structures, the defect and dipole polarization caused by N doping, and the magnetic loss caused by Ni. Meanwhile, the coupling of magnetic and dielectric properties enhances the impedance matching of Ni-MOF@N C. The work proposes a particular idea of designing and synthesizing an applicable microwave absorption material that possesses excellent microwave absorption performance and promising application potential. [ABSTRACT FROM AUTHOR]

Highlights: Electrospinning combined with structural engineering to construct 0D@2D@1D hierarchical heterogeneous interfaces. A "mechanical response" model was constructed to explain the stress transfer mechanism of fibrous membranes with 2D@1D structures. The "One for All" fibrous membrane combines excellent flexibility, mechanical properties, waterproof, and electromagnetic protection. The development of wearable multifunctional electromagnetic protective fabrics with multifunctional, low cost, and high efficiency remains a challenge. Here, inspired by the unique flower branch shape of "Thunberg's meadowsweet" in nature, a nanofibrous composite membrane with hierarchical structure was constructed. Integrating sophisticated 0D@2D@1D hierarchical structures with multiple heterointerfaces can fully unleash the multifunctional application potential of composite membrane. The targeted induction method was used to precisely regulate the formation site and morphology of the metal–organic framework precursor, and intelligently integrate multiple heterostructures to enhance dielectric polarization, which improves the impedance matching and loss mechanisms of the electromagnetic wave absorbing materials. Due to the synergistic enhancement of electrospinning-derived carbon nanofiber "stems", MOF-derived carbon nanosheet "petals" and transition metal selenide nano-particle "stamens", the CoxSey/NiSe@CNSs@CNFs (CNCC) composite membrane obtains a minimum reflection loss value (RLmin) of -68.40 dB at 2.6 mm and a maximum effective absorption bandwidth (EAB) of 8.88 GHz at a thin thickness of 2.0 mm with a filling amount of only 5 wt%. In addition, the multi-component and hierarchical heterostructure endow the fibrous membrane with excellent flexibility, water resistance, thermal management, and other multifunctional properties. This work provides unique perspectives for the precise design and rational application of multifunctional fabrics. [ABSTRACT FROM AUTHOR]

Abstract Transition metal oxides/hydroxides materials attract much attention in the field of energy storage materials because of their high theoretical specific capacity and low cost. However, it is normally difficult to improve the capacitance of the electrode by simply increasing the mass loading or thickness of the electrode. To raise the utilizing efficiency of the active material, hierarchical integrated electrodes assembled by NiCo hydroxide nanowires arrays and reduced graphene oxide interlayers are well designed and synthesized. The surface morphology and inner structure of the hierarchical electrode are characterized by SEM. The electrochemical performances of the electrodes are evaluated by three-electrode and two-electrode system in 2 M KOH respectively. Assisted with two reduced graphene oxide interlayers, NiCo hydroxide nanowires arrays exhibit a specific capacity of 2.41 C cm−2 at 1 mA cm−2. Even at a high current density of 50 mA cm−2, nearly 47% of the capacity could still remain. The results show that, the multi-level nanowires arrays structure provides multi-dimensional transmission path for ions and electrons, and achieved higher specific capacities and rate properties. Graphical abstract Image 1 Highlights • A multi-step hydrothermal method is proposed to prepare hierarchical electrode. • Combination of multi-layer NiCo-H NWAs and rGO interlayers are required. • The hierarchical structure provides multi-dimensional transmission path for ions and electrons. [ABSTRACT FROM AUTHOR]

In this work, the structural design of a structure-simplified parallel Delta robot is presented, by considering the kinetostatics, kinematic dexterity and workspace. An approach to normalize the dimensionally inhomogeneous Cartesian stiffness matrix is introduced, and a stiffness evaluation index is defined by means of the singular value decomposition of homogenized stiffness matrix, which is used in the design optimization in turn. A multi-objective design optimization problem is formulated to provide the optimal solutions of different sets of geometric parameters. A set of parameters is selected to lay out the robot, and the tested specifications show the good performances, although the speed is not so high as the commercial FlexPicker and Quattro. A comparative study is carried out between the proposed and original Delta robots by observing joint dynamics, showing that the modified robot structure can improve the robot dynamics. The presented work turns out that the proposed robot is applicable to the pick-and-place operations without high-precision requirement in most industrial sectors. [ABSTRACT FROM AUTHOR]

Highlights: NiCo/C aerogel was prepared by pyrolysis carbonization self-assembly of NiCo- metal–organic frameworks (MOFs). The assembly mechanism of MOF aerogel was studied by adjusting the ratio of metal ion /BTC. Aerogel combines hydrophobic, lightweight, self-cleaning, and electromagnetic wave absorption properties. Although multifunctional aerogels are expected to be used in applications such as portable electronic devices, it is still a great challenge to confer multifunctionality to aerogels while maintaining their inherent microstructure. Herein, a simple method is proposed to prepare multifunctional NiCo/C aerogels with excellent electromagnetic wave absorption properties, superhydrophobicity, and self-cleaning by water-induced NiCo-MOF self-assembly. Specifically, the impedance matching of the three-dimensional (3D) structure and the interfacial polarization provided by CoNi/C as well as the defect-induced dipole polarization are the primary contributors to the broadband absorption. As a result, the prepared NiCo/C aerogels have a broadband width of 6.22 GHz at 1.9 mm. Due to the presence of hydrophobic functional groups, CoNi/C aerogels improve the stability in humid environments and obtain hydrophobicity with large contact angles > 140°. This multifunctional aerogel has promising applications in electromagnetic wave absorption, resistance to water or humid environments. [ABSTRACT FROM AUTHOR]

Compared with the other absorption materials, multicomponent of CNTs composite materials have become increasingly significant in the preparation of high-performance electromagnetic wave absorption materials due to their unique dielectric-magnetic advantages. In this paper, we use the heating and disintegration of organic amine salt to achieve the restoration of oxides while derivating carbon nanotubes, preparing an excellent performance of Co/Cu/CrN/CNTs composite materials. Due to annealing, slim -shaped CrN evenly attached to the surface of carbon nanotubes. The material forms a rich interface and good impedance matching characteristics, thereby realizing the excellent electromagnetic wave absorption performance of the material. The maximum bandwidth of 7.2 GHz was obtained at 2.62 mm and the minimum reflection loss was – 53.58 dB. The composite material design provides a new way for the development of high-performance electromagnetic wave absorption materials. [Display omitted] • Dicyandiamide derivatives were used to decompose nitriding to achieve the successful synthesis of CrN. • Carbon nanotubes were derived from Co/Cu metal particles as growth sites. • The maximum reflection loss is −53.58 dB and the absorbing bandwidth (<-10 dB) is 7.2 GHz at the same thickness (2.62 mm). [ABSTRACT FROM AUTHOR]

Generally, certain parts of aircraft and weapons, for example, head cone, engine inlet and nozzle, need to be resistant to high-temperature and high-speed heat flow. In order to meet the requirement of stealth of these special parts, the high-temperature structural absorbing materials, for example, ceramic fibers, ceramic matrix composites and creative commons (C/C) materials are being actively developed at home and abroad. Continuous and increasing efforts have also been made in the last decade aiming at developing excellent electromagnetic (EM) wave absorbents, for example, SiC working at high temperature. An ideal EM absorber should be relatively lightweight, thermally stable, capable of broad absorbing frequency and cost effective. Different kinds of high-temperature absorbers including ceramics, carbon-based materials, ferromagnetic materials and metal oxides have been summarized and discussed in this review. This review intends to inspire new concepts and approaches for designing excellent high-temperature microwave-absorbing materials. This work aims at reviewing the progress of high-temperature absorbents obtained in the last decade, and discusses in detail the electromagnetic properties and absorbing performances of some representative absorbers. Then, the key issues and current challenges are proposed to inspire the interested researchers to develop new-type of absorbents with lightweight, broad absorption bandwidth, small thickness, minimum reflection loss, and good thermal stabilities. [ABSTRACT FROM AUTHOR]

Graphene nanosheets (GNSs) and multiwalled carbon nanotubes (MWCNTs) were treated with a nonionic surfactant polyvinylpyrrolidone (PVP), and its effects on dispersion state, surface chemistry, structure, and morphology of MWCNTs and GNSs, as well as on the microwave absorbing properties, mechanical properties of GNSs/MWCNTs/cyanate ester nanocomposites were analyzed respectively. Results show that surfactant plays an important role in dispersing the GNSs and MWCNTs in a solvent and polymer. The mechanical properties, such as impact fracture toughness and flexural strength all showed significant improvements after the treatment. The above observations are attributed to the unique amphiphile structures of PVP, which improved the interface characteristic between matrix and the fillers. Besides, PVP can effectively enhance interfacial interactions which gave rise to improved dispersion and wetting of GNSs and MWCNTs in polymer matrix. Unlike chemical functionalization techniques, however, the surfactant treatment exhibited little adverse effect on microwave absorption properties of the nanocomposite. POLYM. COMPOS., 39:110–118, 2018. © 2016 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]