Typical binary nitrate (NaNO3-KNO3 as 60:40 rat io by weight) based AlN nanofluid was prepared by a two-step solutionmethod. The specific heat capacities of nanofluids with AlN amount ranging from 0.5 to 4 wt. % were ...
Typical binary nitrate (NaNO3-KNO3 as 60:40 rat io by weight) based AlN nanofluid was prepared by a two-step solutionmethod. The specific heat capacities of nanofluids with AlN amount ranging from 0.5 to 4 wt. % were investigated. The results suggest a good compatibility between AlN and molten binary nit rates. Meanwhile, AlN nanoparticles are proved to be an effective additive in improving the thermal properties of binary nitrates. For binary nitrate-based materials, samples with AlN amount as 1 wt. % shows the best thermal enhancement of specific heat capacity.
The two-dimensional (2D) effect is observed in experiments and simulations of long-rod penetration. Different nose shapes may occur in the penetration of long rods made by different materials, which will have an effec...
The two-dimensional (2D) effect is observed in experiments and simulations of long-rod penetration. Different nose shapes may occur in the penetration of long rods made by different materials, which will have an effect on the penetration performances. Base on the 2D model established in authors' previous work, combining with the experimental and simulation results, the 2D effect of long-rod penetration is analyzed in present paper. According to the analysis, the basic assumption of the 2D model, the nose shape of long rods keeps invariant during the primary phase, is verified. In addition, the 2D model can briefly reflect the 2D effect shown in experiments and simulations.
In this paper, a novel carbonate/MgO composite for high temperature thermal storage was prepared by doping nano-SiO2. Na2CO3-K2CO3 eutectic salt was used as the phase change material. The long-term stability of the sa...
In this paper, a novel carbonate/MgO composite for high temperature thermal storage was prepared by doping nano-SiO2. Na2CO3-K2CO3 eutectic salt was used as the phase change material. The long-term stability of the samples was tested by holding at 750°C for a period of time. The differential thermal analysis calorimeter, X-ray diffractometer and scanning electron microscope were employed to detected the possible influences of constant high temperature on thermal properties. The results showed that the doped nano-SiO2 particles can restrain high temperature molten salt loss and improve the stability of the composite in both structure and thermal properties.
Symmetry-breaking phenomena are observed in numerous strongly-correlated systems including high-temperature superconductors. However, identifying these exotic phases and understanding their interplay with superconduct...
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ZrB2/ZrxAlyCz composite ceramics with different volume contents of ZrxAlyCz were fabricated by the spark plasma sintering. The sintering behavior, microstructure, mechanical properties and oxidation resistance were st...
ZrB2/ZrxAlyCz composite ceramics with different volume contents of ZrxAlyCz were fabricated by the spark plasma sintering. The sintering behavior, microstructure, mechanical properties and oxidation resistance were studied. The results indicated that sinterability of the composites was remarkably improved by addition of ZrxAlyCz compared to the single-phase ZrB2 ceramic. As the content of ZrxAlyCz increased, both the Vickers hardness and Young's modulus of the composites first increased and then decreased. The fracture toughness of the ZrB2-40vol% ZrxAlyCz composite was 3.56 MPam1/2, which increased by approximately 70% compared to the monolithic ZrB2 ceramic. As increasing the content of ZrxAlyCz, the oxidation resistance of composite ceramics was obviously enhanced. The oxidation-resulted increase in weight of composite ceramic with 20vol% ZrxAlyCz was the best performance in oxidation resistance at 1500 °C. The high-temperature oxidation resulted in dense and stable Al-B-O glass due to adding ZrxAlyCz into the composite ceramics, those resulting products effectively blocked the oxygen atoms entering into the ceramic matrix.
Zr2Al4C5/SiC composite ceramics were successfully fabricated from the powder mixture of Zr, Al, C and SiC by spark plasma sintering method. The composition-dependent densification, phase evolution, microstructure and ...
Zr2Al4C5/SiC composite ceramics were successfully fabricated from the powder mixture of Zr, Al, C and SiC by spark plasma sintering method. The composition-dependent densification, phase evolution, microstructure and mechanical properties of the composite ceramics were studied. With increasing the SiC content in the starting powder mixture, the densification behavior of sintered samples was promoted. It is found that the as-sintered products are mainly composed of Zr2Al4C5 matrix and SiC reinforcement, and the fine SiC particles tend to disperse on the matrix grain boundaries. Besides, the addition of SiC particles can evidently hinder the coarsening of Zr2Al4C5 grains. Both the Vickers hardness and Young's modulus of composites ceramics gradually increase as increasing the SiC content. The fracture toughness of the composites decreases first then increases with the increase in the SiC and the Zr2Al4C5/30vol%SiC sample possesses the maximum value of 4.4MPam1/2.
Photonic Chern insulators are known for their topological chiral edge states (CESs), whose absolute existence is determined by the bulk band topology, but concrete dispersion can be engineered to exhibit various prope...
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Photonic Chern insulators are known for their topological chiral edge states (CESs), whose absolute existence is determined by the bulk band topology, but concrete dispersion can be engineered to exhibit various properties. For example, the previous theory suggested that the edge dispersion can wind many times around the Brillouin zone to slow down light, which can potentially overcome fundamental limitations in conventional slow-light devices: narrow bandwidth and keen sensitivity to fabrication imperfection. Here, we report the first experimental demonstration of this idea, achieved by coupling CESs with resonance-induced nearly flat bands. We show that the backscattering-immune hybridized CESs are significantly slowed down over a relatively broad bandwidth. Our work thus paves an avenue to broadband topological slow-light devices.
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