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The anisotropy of rare earth magnesium (Mg-RE) alloys has attracted significant attention. In this study, the room-temperature compression anisotropy of the extruded Mg-8.5Gd-4.5Y-0.8Zn-0.4Zr alloy was investigated utilizing techniques such as optical microscope (OM), electron backscatter diffraction (EBSD), and viscoplastic self-consistent (VPSC) modeling. The results show that the C0 (with the axis parallel to the extrusion direction) sample exhibited the greatest yield strength of 290 MPa, while the C45 (with the axis inclined at a 45° angle to the extrusion direction) and C90 (with the axis perpendicular to the extrusion direction) samples had yield strengths of 223 MPa and 250 MPa, respectively. The VPSC hardening parameters were significantly adjusted in this study based on the Schmid factor of deformation modes in Mg-RE alloy, particularly increasing the τ0 (Critical Resolved Shear Stress, CRSS) for basal slip. The ratios of CRSS for other deformation modes to basal slip were approximately as follows: CRSSTwin/CRSSBas = 2, CRSSPri/CRSSBas = 2.7 and CRSSPyr/CRSSBas = 3.3, while these ratios in non-rare earth magnesium alloys typically ranged between 0.8 and 3, 5–10 and 8–20. The stress-strain curves and pole figures obtained from the VPSC model exhibited a good agreement with experimental results. Based on the VPSC simulation results, the disparity in the activation level of basal slip was identified as the primary cause of mechanical anisotropy. Twinning only played a significant role in the early phases of deformation, which was not the most primary factor on yield anisotropy.

In this paper, the microstructure and tensile mechanical properties of Mg-8.5Gd-4.5Y-0.8Zn-0.4Zr rare-earth (RE) magnesium alloy in the as-cast state and its solid solution state were investigated by means of optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron backscatter diffraction (EBSD), X-ray diffraction (XRD), differential scanning calorimeter (DSC) and the first-principles simulation. The results show that the mechanical properties were improved after solution treatment. The CS520-12 alloy, treated at 520 °C for 12 h, exhibited excellent mechanical properties, possessing an ultimate tensile strength (UTS) of 343 ± 5 MPa and an elongation of 18.9 ± 0.8 %. These main reasons for the improving of mechanical properties was attributed the formation of I1 stacking faults (SFs) and accumulated-dislocations. The Y element, originating from the melt of the eutectic phase during solution treatment, resulted in a reduction in stacking faults energy (SFE) and facilitated the formation of I1 faults. The presence of numerous SFs hindered dislocation slip. The other key factors for elongation improving were that the weaken of texture, and geometrically necessary dislocation (GND) density decreased from 1.52 × 1013m−2 to 1.22 × 1013m−2. 14H-LPSO phase played an important role in the improving mechanical properties for CS480-12, CS480-24 and CS520-24 alloys. The higher elastic modulus of LPSO compared to Mg matrix, according to the first-principles calculated results, enabled its function as a short-fiber, thus strengthened the mechanical properties. Block-shaped 14H-LPSO in CS480-12 alloys, distributed at the grain boundaries (GBs), suppressed the grow of cracks. The lamellar 14H-LPSO within the grains of CS480-24 and CS520-24 alloys were parallel to the dislocations, which compared with SFs of CS520-12 alloy, can't effectively inhibit the movement of dislocations.

Graphene with excellent mechanical and physical properties has shown its great application potential in aluminum matrix composites. In this paper, graphene oxide nanosheets with negative charges were fabricated by the Hummers' method and they are absorbed on the treated aluminum powders with positive charges by electrostatic self-assembly. Then, graphene reinforced aluminum matrix composites (Gr/Al) were prepared by powder metallurgy. The effects of the Gr content on mechanical performance and corrosion resistance were investigated. The results show that Gr is distributed at the boundary and bonds well with aluminum in Gr/Al composite. Mechanical properties of the composite initially increase then decrease with the increase of Gr content. When the Gr content reaches 0.3 wt%, the ultimate tensile strength reaches 110 MPa and the wear coefficient is 0.39. However, the corrosion resistance decreases with increasing the Gr content and the corrosion mechanism is also investigated in details.

Molecular dynamics (MD) simulation and experiments were carried out in this work to probe the microstructure evolution in the semi-solid compression (SSC) of AZ80 magnesium alloy. The liquid phase flow, stress fluctuations, grain refinement, dislocation generation, and texture evolution were discussed. Results indicate that the liquid phase was squeezed out along the radial direction prior the solid phase at the beginning of compression. Stress-strain curve represented obvious fluctuation at lower strain rates. That resulted from stress reduction caused by more liquid evolving with a lower strain rate at an elevated temperature. Plastic deformation was detected in grains and the dislocations of 1/3 dominated the deformation, while and 1/3 just been activated at the beginning of SSC process. The results of EBSD showed the grains size was refined into about 38.8 μm from 92.3 μm after SSC process. During the process, grain refinement resulted in the increase of low-angle grain boundaries (LAGBs), and a strong (0001) basal plane texture evolved at the end. The higher the strain rates, the stronger the texture.

Long-term ischemia leads to insufficient cerebral microvascular perfusion and dysfunction. Reperfusion restores physiological fluid shear stress (FSS) but leads to serious injury. The mechanism underlying FSS-induced endothelial injury in ischemia–reperfusion injury (IRI) remains poorly understood. In this study, a rat model of middle cerebral artery occlusion was constructed to explore cerebrovascular endothelial function and inflammation in vivo. Additionally, the rat brain microvascular endothelial cells (rBMECs) were exposed to a laminar FSS of 0.5 dyn/cm2 for 6 h and subsequently restored to physiological fluid shear stress level (2 dyn/cm2) for 2 and 12 h, respectively. We found that reperfusion induced endothelial-to-mesenchymal transition (EndMT) in endothelial cells, leading to serious blood–brain barrier dysfunction and endothelial inflammation, accompanied by the nuclear accumulation of Yes-associated protein (YAP). During the later stage of reperfusion, cerebral endothelium was restored to the endothelial phenotype with a distinct change in mesenchymal-to-endothelial transition (MEndT), while YAP was translocated and phosphorylated in the cytoplasm. Knockdown of YAP or inhibition of actin polymerization markedly impaired the EndMT in rBMECs. These findings suggest that ischemia–reperfusion increased intensity of FSS triggered an EndMT process and, thus, led to endothelial inflammation and tissue injury, whereas continuous FSS induced a time-dependent reversal MEndT event contributing to the endothelial repair. This study provides valuable insight for therapeutic strategies targeting IRI.

Abstract Two-dimensional (2D) molybdenum disulfide (MoS2) has been recognized as a potential substitution of platinum (Pt) for electrochemical hydrogen evolution reaction (HER). However, the broad adoption of MoS2 is hindered by its limited number of active sites and low inherent electrical conductivity. In this work, we employed a one-step solvothermal synthesis technique to construct a ternary hybrid structure consisting of dual-phase MoS2, titanium carbide (Ti3C2) MXene, and carbon nanotubes (CNTs), and demonstrated synergistic effects for active site exposure, surface area enlargement, and electrical conductivity improvement of the catalyst. The dual-phase MoS2 (DP-MoS2) is directly formed on the MXene with CNTs acting as crosslinks between 2D islands. The existence of edge-enriched metallic phase MoS2, the conductive backbone of MXene along with the crosslink function of CNTs clearly improves the overall HER performance of the ternary nanocomposite. Moreover, the integration of MoS2 with MXene not only increases the interlayer distance of the 2D layers but also partially suppresses the MXene oxidation and the 2D layer restacking, leading to good catalytic stability. As a result, an overpotential of 169 mV and a low Tafel slope of 51 mV/dec was successfully achieved. This work paves a way for 2D-based electrocatalyst engineering and sheds light on the development of the next-generation noble metal-free HER electrocatalysts.

Silicon has gained considerable attention as an anode material in lithium-ion batteries due to its high theoretical capacity. However, the significant volume changes that occur during lithiation/delithiation processes often result in poor cycling stability of silicon anodes. In this study, a hybrid ionically covalently cross-linked network binder carboxymethylcellulose-hyperbranched polyethyleneimine (CMC-HBPEI) is successfully constructed by “switching” ionic bonds and partially “converting” them to covalent bonds to buffer the volume variation of silicon anodes. In this hybrid cross-linked network, the covalently cross-linked network is responsible for maintaining the structural integrity of the anode, while the ionically cross-linked network utilizes the bonding reversibility to sustainably dissipative the mechanical stress and self-heal the structural breakages generated from the lithiation expansion of silicon. By changing the drying temperature of the anode, the ratio of covalent and ionic bonds in the hybrid cross-linked network can be adjusted to balance the mechanical stability and bonding reversibility of the CMC-HBPEI binder. Even after 300 cycles of charging/discharging under a current density of 500 mAg−1, the specific capacity of the optimized Si/CMC-HBPEI anode remains at 1545 mAhg−1.

Graphitic carbon nitride (g-C3N4) nanosheets were exfoliated from bulk g-C3N4 and utilized to improve the sensing performance of a pure graphene sensor for the first time. The role of hydrochloric acid treatment on the exfoliation result was carefully examined. The exfoliated products were characterized by X-ray diffraction (XRD) patterns, scanning electron microscopy (SEM), atomic force microscopy (AFM), and UV-Vis spectroscopy. The exfoliated g-C3N4 nanosheets exhibited a uniform thickness of about 3–5 nm and a lateral size of about 1–2 µm. A g-C3N4/graphene nanocomposite was prepared via a self-assembly process and was demonstrated to be a promising sensing material for detecting nitrogen dioxide gas at room temperature. The nanocomposite sensor exhibited better recovery as well as two-times the response compared to pure graphene sensor. The detailed sensing mechanism was then proposed.

Highly efficient recognition and detection of chiral molecules with similar structures are of great significance in the fields of medicine and biochemistry. In this study, strobili fibers of the plane tree were carbonized at high temperatures to prepare hollow chiral helical carbon tubes (HCT). Subsequently, l-threonine (l-Thr) was nanoassembled on the HCT surface (l-Thr@HCT) through hydrogen bonding and electrostatic interactions. Benefiting from the synergistic effect of conductive HCT with inherent chirality and l-Thr with abundant chiral sites, the electrode demonstrates a satisfied recognition efficiency of 3.20 for the cysteine (Cys) enantiomer. The l-Thr@HCT/GCE electrode exhibits a lower affinity toward l-Cys than d-Cys, thereby facilitating the diffusion of l-Cys to the electrode surface and exhibiting excellent selectivity for l-Cys. Under the optimal conditions, the electrode has a high sensitivity of 1.74 μA·mM-1 for l-Cys with a low detection limit of 8.58 μM (S/N = 3). Moreover, the electrode has good repeatability, reproducibility, and stability. This electrode will have a potential clinical application in chiral sensing. [ABSTRACT FROM AUTHOR]

The general principles of design and development of microwave absorbing materials are discussed and analysed in respect to 26-37 GHz frequency range (Ka-band). Dispersive composite materials based on carbon nanotubes in epoxy resin matrix are produced, and their electromagnetic responses are investigated in Ka-band. Both theoretical and experimental results demonstrate that presented composites may be used as compact effective absorbers in 26-37 GHz range. [ABSTRACT FROM AUTHOR]

Graphitic carbon nitride (g-C3N4) nanosheets were exfoliated from bulk g-C3N4 and utilized to improve the sensing performance of a pure graphene sensor for the first time. The role of hydrochloric acid treatment on the exfoliation result was carefully examined. The exfoliated products were characterized by X-ray diffraction (XRD) patterns, scanning electron microscopy (SEM), atomic force microscopy (AFM), and UV-Vis spectroscopy. The exfoliated g-C3N4 nanosheets exhibited a uniform thickness of about 3-5 nm and a lateral size of about 1-2 μm. A g-C3N4/graphene nanocomposite was prepared via a self-assembly process and was demonstrated to be a promising sensing material for detecting nitrogen dioxide gas at room temperature. The nanocomposite sensor exhibited better recovery as well as two-times the response compared to pure graphene sensor. The detailed sensing mechanism was then proposed. [ABSTRACT FROM AUTHOR]

In this article, analysis has been made with regard to current situation of ecological revetment works and revetment requirements of river channels in the middle and lower reaches of Yangtze River, types of ecological revetment and etc. The development trend of ecological revetment and its application prospect are also discussed. The analysis indicates that, after the impoundment of Three Gorge Reservoir, the erosion of the river channels in the middle and lower reaches of Yangtze River will result in severe situation like local river channel adjustment and local bank collapse and continuous weakening of river ecological system. It is necessary to keep on strengthening the comprehensive control of the river reaches adopting in the future. [ABSTRACT FROM AUTHOR]

Novel side-heating gas sensor based on ZnO nanorod circular arrays was firstly fabricated by hydrothermal treatment assisted with a kind of simple dip-coating technique. The structure and morphologies of ZnO nanorods were characterized by X-ray diffraction (XRD), Scanning Electron Microscope (SEM), respectively. XRD result indicates that the obtained ZnO nanorods have good crystalline with the hexagonal wurtzite structure. SEM result indicates that ZnO nanorod arrays are vertically growth on the surface of ceramic tube of side-heating sensor with controlled diameter and length, narrow size distribution and high orientation. The gas sensing properties of ZnO nanorod circular arrays are also evaluated. Comparative to the sensor based on scattered ZnO nanorods responding to 25 ppm H2, CO, C6H5CH3 and C2H5OH gas, respectively, the sensing values of high orientation gas sensor are generally increased by 5%. This novel sensor has good application promising for the fabrication of cost effective and high performance gas sensors.