Materials with an ultralow density and ultrahigh electromagnetic‐interference (EMI)‐shielding performance are highly desirable in fields of aerospace, portable electronics, and so on. Theoretical ...work predicts that 3D carbon nanotube (CNT)/graphene hybrids are one of the most promising lightweight EMI shielding materials, owing to their unique nanostructures and extraordinary electronic properties. Herein, for the first time, a lightweight, flexible, and conductive CNT–multilayered graphene edge plane (MLGEP) core–shell hybrid foam is fabricated using chemical vapor deposition. MLGEPs are seamlessly grown on the CNTs, and the hybrid foam exhibits excellent EMI shielding effectiveness which exceeds 38.4 or 47.5 dB in X‐band at 1.6 mm, while the density is merely 0.0058 or 0.0089 g cm−3, respectively, which far surpasses the best values of reported carbon‐based composite materials. The grafted MLGEPs on CNTs can obviously enhance the penetration losses of microwaves in foams, leading to a greatly improved EMI shielding performance. In addition, the CNT–MLGEP hybrids also exhibit a great potential as nano‐reinforcements for fabricating high‐strength polymer‐based composites. The results provide an alternative approach to fully explore the potentials of CNT and graphene, for developing advanced multifunctional materials.
Carbon nanotube–multilayered graphene edge plane core–shell hybrid foams are fabricated by chemical vapor deposition methods for the first time. The seamless junctions of multilayered graphene edge planes on the carbon nanotubes endow the hybrids with potential applications as high‐performance nanocomposites and ultrahigh‐performance lightweight electromagnetic‐interference shielding materials.
Hierarchical Co3O4@NiCoLDH nanosheets (NSs) were prepared on carbon cloth through a multistep method, containing Metal-organic frameworks (MOF)-templated thermal annealing and electrodeposition. The ...triangle-shaped Co3O4NSs were firstly obtained by thermal treatment of MOF templates in air. Then, ultrathin NiCoLDHNSs were in-situ electrodeposited on the surface of Co3O4NSs, constructing a core-shell structure. Benefiting the unique hierarchical structure, high conductivity of Co3O4NSs core and large surface area of NiCoLDHNSs shell, the Co3O4@NiCoLDHNSs array served as supercapacitor electrode exhibits excellent electrochemical properties, such as high specific capacitance of 1708 F g−1 (850 C g−1) at a current density of 1 A g−1, good rate capability, and excellent cycling stability. Further, the asymmetric supercapacitor assembled by Co3O4@NiCoLDHNSs and activated carbon, also displays superior electrochemical performance with high energy density and power density. Remarkably, the strategy of constructing core-shell structure based on MOF templates could be extended to other electrochemical fields.
•Lightweight and flexible 3D graphene microtubes membrane has been fabricated.•Interconnected edge-rich VGNs were grown on interwoven conductive CMTs networks.•The 3D GMTs membrane exhibits highly ...shows ultrahigh EMI shielding performance.
Ultralight, flexible and high-performance electromagnetic-interference (EMI) shielding performance materials are urgently required in the areas of aircraft/aerospace, portable and wearable smart electronics. Benefiting from the outstanding properties of graphene and the unique architectures, 3D assembled graphene structures have been widely applied in the field of EMI-shielding. Herein, for the first time, using Si3N4 nanowires as self-sacrificial templates with the thermal decomposition characteristics, 3D graphene microtubes (3DGMTs) membrane is fabricated by plasma enhanced chemical vapor deposition (PECVD) method, exhibiting the characteristics of free-standing and flexibility. 3DGMTs membrane assembled with silicon carbide (SiC) nanocrystals decorated edge-rich vertical graphene nanosheets (VGNs) exhibits superb EMI shielding effectiveness (SE) of around 38 dB in the frequency range of 8.2~12.4 GHz at a density of 0.0036 g cm−3 and a thickness of 1.5 mm. Considering the ultralow density and thickness, 3DGMTs membrane shows a high specific SE (SSE, defined as SE divided by mass density) of 10,556 dB cm3 g−1 in X-band, which far surpasses that of almost all the reported materials. Remarkably, our work not only provides a new idea for preparation of hollow tubular carbon materials for a wide range of applications, but also presents some fundamental insights for edge-rich VGNs applied in EMI shielding.
The association between non-alcoholic fatty liver disease (NAFLD) and osteoarthritis (OA) has not been well elucidated. The aim of the present study was to investigate the association between NAFLD ...and OA in the US adults.
A cross-sectional study was performed on participants in the 2017-2018 National Health and Nutrition Examination Survey (NHANES) cycle. NAFLD was defined by the vibration-controlled transient elastography. The diagnosis of OA was based on self-reported data. Weighted multiple logistic regression models and stratified analyses were performed to explore the relationship and verify the stability of the conclusions. Sensitivity analysis using multiple imputation for missing data and propensity score matching (PSM) were performed.
In total, 2622 participants Male: 1260 (47.8%) were included in this study with a mean age of 48.1 years old (95% CI, 46.6-49.6 years old), containing 317 (12.8%) OA patients and 1140 NAFLD patients (41.5%). A logistic regression indicated a significant association between NAFLD and OA without adjustment odds ratio (OR) = 2.05; 95% CI, 1.52-2.78. The association remained stable after adjustment for covariates (OR = 1.72; 95% CI, 1.26-2.34). Sensitivity analysis of missing data with multiple interpolation and PSM found similar results. A significant and consistent association of NAFLD with OA was still observed in each subgroup stratified by age and metabolic syndrome (MetS). Stratified by sex, obesity, and sensitivity c-reactive protein (hs-CRP) category, a statistically significant association was only shown in females, those without obesity, and those without hyper hs-CRP. The results illustrated that the relationship between NAFLD and OA was stable in all subgroups and had no interaction.
NAFLD was positively correlated with OA. Given the current pandemic of NAFLD and OA, clinicians should screen for NAFLD in arthritis patients and intervene early.
A novel process for preparing carbon nanotubes (CNTs) reinforced magnesium nanocomposites were developed, which combined friction stir processing (FSP) and ultrasonic assisted extrusion. A very good ...dispersion of CNTs in AZ91D alloy could be observed. It was demonstrated that the strength of Mg nanocomposites was remarkably enhanced. This was contributed to dislocation strengthening mechanism and stress transfer mechanism, not concerned with the grain refinement. Moreover, the composites maintained good ductility. The interfaces between CNTs and Mg matrix were well bonded, and the interfacial reaction product formation of Al2MgC2 was confirmed. A few edge dislocations were observed at CNTs-matrix boundaries by adding carbon nanotubes.
•CNTs/Mg nanocomposites was fabricated by a novel mixed method.•Strength of 1.0 vol%CNTs/Mg composites was enhanced without sacrificing ductility.•The amount of Mg17Al12 phase decreased with increasing CNTs concentration.•The CNTs-matrix interfacial reaction product formation of Al2MgC2 was found.
The aligned one-dimensional channels found in covalent organic frameworks offer a unique space for energy storage. However, physical isolation of sulfur in the channels is not sufficient to prevent ...the shuttle of lithium-sulfide intermediates that eventually results in a poor performance of lithium-sulfur energy storage. Herein, we report a strategy based on imine-linked frameworks for addressing this shuttle issue by covalently engineering polysulfide chains on the pore walls. The imine linkages can trigger the polymerization of sulfur to form polysulfide chains and anchor them on the channel walls. The immobilized polysulfide chains suppress the shuttle effect and are highly redox active. This structural evolution induces multifold positive effects on energy storage and achieves improved capacity, sulfur accessibility, rate capability and cycle stability. Our results suggest a porous platform achieved by pore wall engineering for tackling key issues in energy storage.
•The ablation of C/C composites is dominated by mechanical exfoliation.•CNTs were introduced into C/C composites without metal catalysts by EPD.•Thermal conductivity and fiber-matrix interfaces are ...improved by EPD CNTs.•Introducing CNTs decreases the mechanical ablation of C/C composites by 64%.
CNTs have been introduced into C/C composites by electrophoretic deposition to improve their ablation performance. Mass ablation of C/C composites decreases by 64% with an optimized CNT content. Mechanical exfoliation is mainly responsible for the mass loss of C/C composites under oxyacetylene ablation as confirmed by SEM observations and static oxidation experiments. By applying CNTs with an optimized content, thermal conductance of the composites increases by 24.5% and the fiber-matrix interfacial strength increases by 74.6%. Local thermal damage is significantly relieved and matrix peeling off by high-velocity gas is inhibited, which lead to the significant decrease of mechanical ablation.
Assembly of 3D micro/nanostructures in advanced functional materials has important implications across broad areas of technology. Existing approaches are compatible, however, only with narrow classes ...of materials and/or 3D geometries. This paper introduces ideas for a form of Kirigami that allows precise, mechanically driven assembly of 3D mesostructures of diverse materials from 2D micro/nanomembranes with strategically designed geometries and patterns of cuts. Theoretical and experimental studies demonstrate applicability of the methods across length scales from macro to nano, in materials ranging from monocrystalline silicon to plastic, with levels of topographical complexity that significantly exceed those that can be achieved using other approaches. A broad set of examples includes 3D silicon mesostructures and hybrid nanomembrane–nanoribbon systems, including heterogeneous combinations with polymers and metals, with critical dimensions that range from 100 nm to 30 mm. A 3D mechanically tunable optical transmission window provides an application example of this Kirigami process, enabled by theoretically guided design.
Environment-friendly concrete is gaining popularity these days because it consumes less energy and causes less damage to the environment. Rapid increases in the population and demand for construction ...throughout the world lead to a significant deterioration or reduction in natural resources. Meanwhile, construction waste continues to grow at a high rate as older buildings are destroyed and demolished. As a result, the use of recycled materials may contribute to improving the quality of life and preventing environmental damage. Additionally, the application of recycled coarse aggregate (RCA) in concrete is essential for minimizing environmental issues. The compressive strength (CS) and splitting tensile strength (STS) of concrete containing RCA are predicted in this article using decision tree (DT) and AdaBoost machine learning (ML) techniques. A total of 344 data points with nine input variables (water, cement, fine aggregate, natural coarse aggregate, RCA, superplasticizers, water absorption of RCA and maximum size of RCA, density of RCA) were used to run the models. The data was validated using k-fold cross-validation and the coefficient correlation coefficient (R
), mean square error (MSE), mean absolute error (MAE), and root mean square error values (RMSE). However, the model's performance was assessed using statistical checks. Additionally, sensitivity analysis was used to determine the impact of each variable on the forecasting of mechanical properties.
•Two heat fluxes were used to evaluate the ablation of modified C/C composites.•C/C–ZrB2–ZrC–SiC has the lowest ablation rate under a heat flux of 2.38MW/m2.•Ablation rates of C/C shows the smallest ...increase with increase in heat flux.•Thermal mismatch and evaporation of SiO2 dominate variations in the ablation behavior.
Carbon/carbon composites modified by ZrB2–ZrC–SiC particles (C/C–Z–SiC), C/C–Z and C/C were ablated by oxyacetylene torch using two different heat fluxes to investigate the effect of doped ceramic particles. Results indicated that C/C–Z–SiC had the best ablation property in heat flux of 2.38MW/m2 whereas their ablation rates increased fastest when heat flux rising from 2.38 to 4.18MW/m2. C/C composites had the poorest ablation property in the lower heat flux and their ablation rates increased slowest. Thermal mismatch of Z, SiC and C and evaporation of SiO2 induced the various ablation behavior.
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