For conversion of renewable biomass, boron (B)-doped porous c/SiOx composites (B@c/SiOx) were prepared from rice husks and H3BO3 via a simple annealing process. The introduction of B induces the extrinsic defects and ...
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For conversion of renewable biomass, boron (B)-doped porous c/SiOx composites (B@c/SiOx) were prepared from rice husks and H3BO3 via a simple annealing process. The introduction of B induces the extrinsic defects and additional active sites, tunes the chemistry of carbon skeleton, and improves electrochemical performance of composites. The B-doped c skeleton substantially relieves volume change of SiOx and enhances the electronicconductivity of composites. The unique porous structure, large specific surface area, and B-doping endow B@c/SiOx with the high cycling capacity, excellent rate property, and exceptional cycling stability. Moreover, B doping can significantly decrease the Li+ migration barrier in c matrix of c/SiOx. When applied as Li-ion batteries anode, the optimized electrode harvests a cycling capacity of 1040 mAh g(-1) under 0.1 A g(-1) after 100 cycles with an elevated initial coulombic efficiency (cE) of 70.2%, and long cycle life up to 1000 cycles with a capacity of 610 mAh g(-1) under 1.0 A g(-1). This research sheds light on the thoughts of biomass-derived materials for sustainable energy storage devices.
A novel Ti-Ni-Si brazing filler metal was designed and fabricated to braze the c/ccomposite and c/ccomposite, and c/ccomposite and TiAl intermetallic alloy at 1060 degrees c for 10 min. The interfacial microstructu...
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A novel Ti-Ni-Si brazing filler metal was designed and fabricated to braze the c/ccomposite and c/ccomposite, and c/ccomposite and TiAl intermetallic alloy at 1060 degrees c for 10 min. The interfacial microstructures and mechanical properties were investigated, and the enhancing mechanism of the joint strength was elucidated. The results showed that a perfect interface joint was achieved by using TiNiSi to braze the c/ccomposite. Ductile Ti3Sic2 carbide was formed at the interface, which is beneficial to the joint bonding effect. The direct joining between the c/ccomposite and TiAl alloy using TiNiSi filler metal was unsuccessful, which was attributed to the high content of intermetalliccompounds and hard-brittle phases in the brazed joint. The addition of a cu interlayer to the joint can adjust the interfacial structure and reduce the content of brittle compounds, leading to a complete connection between the c/ccomposite and TiAl alloy. The interfacial transition layer on the c/ccomposite side mainly consisted of Ti3Sic2, Ti3Alc ductile ceramic phases, and Tic phase, which enhanced the performance of the brazed joint. The average shear strength at room temperature was 18.8 MPa, with the maximum value of 23.6 MPa, and the average shear strength at 600 degrees c was 25.8 MPa.
The present study investigated the high-speed deformation behavior of 6Ni-0.2N-0.1c steel. 0.2% proof stress (0.2% PS) of the 6Ni-0.2N-0.1c steel increased with an increase in strain rate ((epsilon) over dot) but tens...
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The present study investigated the high-speed deformation behavior of 6Ni-0.2N-0.1c steel. 0.2% proof stress (0.2% PS) of the 6Ni-0.2N-0.1c steel increased with an increase in strain rate ((epsilon) over dot) but tensile strength (TS) indicated almost the same value at (epsilon) over dot above 10(-1) s(-1). Uniform elongation (***) largely decreased with an increase in (epsilon) over dot. TS and *** of the 6Ni-0.2N-0.1c steel at 103 s(-1) were almost the same as those of SUS304 steel. When the effect of (epsilon) over dot on mechanical properties was compared between the 6Ni-0.2N-0.1c and SUS304 steels, the strain rate dependence on 0.2% PS was larger in the 6Ni-0.2N-0.1c steel and that on TS was different at (epsilon) over dot above 10(0) s(-1). And the decrease of *** with an increase in (epsilon) over dot was larger in the 6Ni-0.2N-0.1c steel. The decrease of *** at 10(3) s(-1) was discussed from the viewpoint of change of flow stress at the maximum load point with an increase in (epsilon) over dot. The estimated results proposed that austenite phase hardly transformed into deformation-induced martensite (alpha') up to the maximum load point at 10(3) s(-1) in the 6Ni-0.2N-0.1c steel. The tensile properties of the 6Ni-0.2N-0.1c steel are largely influenced by the higher strength of alpha'. It is difficult for the 6Ni-0.2N-0.1c steel to produce TRIP effect at high strain rates because the deformation-induced martensitic transformation is suppressed.
Poor intrinsicconductivity has been a principal limiting factor for Na3V2(PO4)3 (NVP) cathode material. Herein, a synergistic strategy of Nb5+ substitution and constructing with three-dimensional rGO lamella is propo...
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Poor intrinsicconductivity has been a principal limiting factor for Na3V2(PO4)3 (NVP) cathode material. Herein, a synergistic strategy of Nb5+ substitution and constructing with three-dimensional rGO lamella is proposed for the first time to optimize the characteristics of NVP. The introduction of Nb5+ generates beneficial carriers and vacancies that optimize the electronic structure of NVP system. Meanwhile, rGO substrate can construct an effective conductive network for the facilitated electronic transportation and form a stabilized SEI layer after cycling to protect the active particles from being collapsed. This double treatment significantly improves the kineticcharacteristics of NVP. Moreover, theoretical calculations indicate that beneficial Nb5+ doping can effectively reduce the band gap between conductive and valence bands, as well as decline the energy barrier of migration for Na+. Notably, the modified Nb0.15-NVP/c@rGO exhibits impressive electrochemical performance. It delivers a capacity of 107.9 mAh g-1 and keeps a value of 102.6 mAh g-1 after 500 cycles at 2c with a high retention of 95.35%. It submits a capacity value of 97.2 mAh g-1 at 20c, 82.92% reversible capacity (80.6 mAh g-1) could be retained after 2000 cycles. Even at 120 and 300c, this material still performs high values of 84.9 and 71.3 mAh g-1, indicating the superior rate capability.
The electrical properties of c/Siccomposites could be used for online and in-situ damage monitoring. To investigate alternating current (Ac) impedance response to damage in the c/Siccomposites, monotonic and increme...
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The electrical properties of c/Siccomposites could be used for online and in-situ damage monitoring. To investigate alternating current (Ac) impedance response to damage in the c/Siccomposites, monotonic and incremental cyclic tensile tests were performed. Both Ac impedance and acoustic emission (AE) techniques were applied to clarify the damage evolution during the tests. The relationship between damage and electrical impedance response was investigated and validated via macroscopic equivalent circuit models. The effects of longitudinal deformation and damage on Ac impedance characteristics, including impedance magnitude and phase angle, were obtained from the models. Results showed that the longitudinal deformation increases the impedance magnitude and the phase angle, and the damage causes the impedance magnitude to increase and the phase angle to decrease. The phase angle is significantly sensitive to fiber breakage, which makes the Ac-based method more suitable for online damage monitoring and final failure warning.
Metallic foam was introduced as an interlayer to improve the performance of the brazed c/ccomposite-titanium alloy joint, and the interfacial microstructure and residual stress of the brazed joint were investigated. ...
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Metallic foam was introduced as an interlayer to improve the performance of the brazed c/ccomposite-titanium alloy joint, and the interfacial microstructure and residual stress of the brazed joint were investigated. compared with the brazed joint without foam, introducing foam interlayer could achieve the uniform bonding interface, and Ag-based solid solution (Ag(s,s)) became more dispersed and smaller in the center of the brazing seam. The thickness of reaction layer close to c/ccomposite side was less than 1 mu m. Some cu-based solid solution (cu(s,s)) was detected, indicating that cu foam still existed after brazing. The residual stress and its distribution calculated by finite element method (FEM), and the residual stress of the brazed joint decreased from 293 MPa to 228 MPa. The introduction of the foam interlayer could obtain homogeneous microstructure, change stress distribution, and improve mechanical properties of the brazed joints.
Aerobiccomposting is an efficient and environmentally friendly method of converting organic waste into nontoxic fertilizers or soil quality enhancers. The quality of the resultant compost depends greatly upon the com...
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Aerobiccomposting is an efficient and environmentally friendly method of converting organic waste into nontoxic fertilizers or soil quality enhancers. The quality of the resultant compost depends greatly upon the composition of the substrate used. The initial carbon-to-nitrogen (c/N) ratio of the substrate is an important factor affecting the composting process. This study elucidated how initial c/N ratios affect the biodegradation of lignocellulose, due to changes in microbial community structure. Four different c/N ratios (20:1, 25:1, 30:1, and 35:1) were examined during a 35-day composting process. The degradation of cellulose, hemicellulose, and lignin was highest (35.7%, 30.6%, and 19.1% respectively) at a 30:1 c/N ratio;after 30 days, the 25:1 c/N ratio ranked second in terms of lignocellulosic degradation rate. The 30:1 c/N ratio further promoted the growth of functional microorganisms responsible for lignocellulose degradation (Luteimonas, Sphingobium, Trichoderma, chaetomium, and Rosellinia), while the growth of dominant pathogenic microbes (Erwinia and Ulocladium) decreased significantly. These results confirm that the initial c/N ratio of the substrate has a significant effect on the microbial community and degradation of organic matter, during walnut branch composting. This process could therefore offer an alternative means of efficient recycling and recovery of waste branches.
A chromium carbide (cr-c) coating in-situ formed on the c/c substrate is successfully prepared by a novel reactive wetting strategy. The interfacial microstructure and oxidation resistance of coated c/ccomposites are...
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A chromium carbide (cr-c) coating in-situ formed on the c/c substrate is successfully prepared by a novel reactive wetting strategy. The interfacial microstructure and oxidation resistance of coated c/ccomposites are investigated in detail. The as-prepared coating mainly consists of cr23c6 and cr7c3, forming a tight joining with the c/c substrate. compared to uncoated samples, the oxidation weight loss of coated c/ccomposites is sub-stantially reduced at high temperatures. Furthermore, the hardness of coated c/ccomposites is significantly increased, enhancing their ability to resist external damage. This reactive wetting strategy can also be used to prepare uniform coatings on c/ccomposites with complex grooved structure or large size. Surprisingly, coated c/ccomposites possess a low weight gain of 3.7% due to thin coating (< 10 mu m), which can maintain their advantage of low density.
Polystyrene nanoparticles (PS-NPs) have a potential toxicity on offspring after the exposure. However, the molecular basis for PS-NP in inducing transgenerational toxicity remains largely unknown. In this study, the r...
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Polystyrene nanoparticles (PS-NPs) have a potential toxicity on offspring after the exposure. However, the molecular basis for PS-NP in inducing transgenerational toxicity remains largely unknown. In this study, the role and the underlying mechanism of germline Wnt signaling in regulating transgenerational toxicity of PS-NPs were determined using an in vivo animal model of caenorhabditis elegans. Exposure to PS-NP (1-100 mu g/L) increased expression of Wnt ligand LIN-44 and decreased expression of Wnt receptor MIG-1. After the exposure, the transgenerational PS-NP toxicity on locomotion behavior and brood size were inhibited in lin-44(RNAi) nematodes, while enhanced in mig-1(RNAi) nematodes. The resistance to transgenerational PS-NP toxicity induced by RNAi of lin-44 in P0 generation (P0-G) was inhibited by RNAi of mig-1 in F1-G. In addition, after PS-NP exposure, germline RNAi of lin-44 at P0-G could increase the mig-1 expression in F1-G. Exposure to PS-NP (1-100 mu g/L) further decreased expressions of Dishevelled proteins of DSH-1/2, increased APccomplex component APR-1, and decreased expression of BAR-1/beta-catenin. Meanwhile, transgenerational PS-NP toxicity was enhanced by RNAi of dsh-1, dsh-2, or bar-1 and inhibited by RNAi of apr-1, suggesting that the DSH-1/2-APR-1-BAR-1 signaling cascade acted downstream of Wnt receptor MIG-1 to control transgenerational PS-NP toxicity. Moreover, BAR-1 acted upstream of DVE-1 to activate mitochondrial unfolded protein response (mt UPR) against the transgenerational PS-NP toxicity. Our data highlights the potential link between alteration in germline Wnt signaling and induction of transgenerational nanoplastic toxicity in organisms.
Excessive discharge of toxic dyes is detrimental to ecological system and human health. Therefore, an effective photocatalyst must be designed and developed to degrade dyes from wastewater. Herein, a novel one-dimensi...
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Excessive discharge of toxic dyes is detrimental to ecological system and human health. Therefore, an effective photocatalyst must be designed and developed to degrade dyes from wastewater. Herein, a novel one-dimensional (1D) flower-like recoverable ZnFe2O4/c/MnO2/BiOI magneticcomposite photocatalyst was synthesized via electrospinning technique combined with hydrothermal method. The photocatalytic activities of composite photocatalyst were evaluated by degrading methyl orange (MO) and Rhodamine B (RhB) under simulated light irradiation. The efficiency of ZnFe2O4/c/MnO2/BiOI photocatalyst in visible light for 150 min reached 91% (MO) and 120 min reached 94% (RhB). Moreover, the degradation rate of MO still remained 78% after five cycles. The design of 1D magnetic flower-like composite provided a new strategy for preparing photocatalysts possessing excellent photocatalytic efficiency and cyclic stability.
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