Carbon materials are generally employed as supercapacitor electrodes due to their low- cost, high-chemical stability and environmental friendliness. However, the design of carbon structures with large surface area and controllable porous structure remains a daunt challenge. In this work, a three-dimensional (3D) hybrid aerogel with different contents of MoS2 nanosheets in 3D graphene aerogel (MoS2-GA) was synthesized through a facial hydrothermal process. The influences of MoS2 content on microstructure and subsequently on electrochemical properties of MoS2-GA are systematically investigated and an optimized mass ratio with MoS2: GA of 1:2 is chosen to achieve high mechanical robustness and outstanding electrochemical performance in the hybrid structure. Due to the large specific surface area, porous structure and continuous charge transfer network, such MoS2-GA electrodes exhibit high specific capacitance, good rate capability and excellent cyclic stability, showing great potential in large-scale and low-cost fabrication of high-performance supercapacitors.

A numerical study of the longitudinal pulsed detonation (LPD) is conducted in the present paper. The occurrence mechanism of the LPD, called shock wave amplification by coherent energy release (SWACER) is verified preliminarily in this study. To be specific, upstream propagating shock waves, which originate from the outlet, induce a specific gradient of reactant distribution and then detonation waves are ignited and evolve along the gradient in close succession. It is worth noting that the occurrence of LPD does not mean that the LPD will necessarily be sustained. The low injection pressure ratio PR (i.e. the ratio of inlet pressure to outlet pressure) = 1.3 is found to be conducive to the sustenance of the LPD instability in the baseline model. A lower PR (PR {less than or equal to} 1.2) or a slightly higher PR (1.4 {less than or equal to} PR {less than or equal to} 1.8) shall lead to an unstable detonation or a quenching of detonations, while a much higher PR (PR > 1.8) contributes to the formation of stable canonical rotating detonation waves. In addition, the combustion regimes of five combustors of different heights at different PR are explored. As the combustion chamber height increases, the PR of the sustainable LPD is nearly linearly increasing and its operating frequency decreases gradually. The calculation formula between the sustainable LPD propagating frequency and natural acoustic resonance frequency of the combustor is employed and discussed, but in consideration of its imperfection further investigation is required.

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In general, pressure sensitive paint (PSP) and thermochromic liquid crystal (TLC) are used to indicate film cooling efficiency. However, due to the mechanisms of PSP and TLC being different, their results are not consistent in some cases. Thus, analyzing the divergence between these two measurement methods is essential. In this paper, a comparison of measured film cooling efficiency distribution between PSP and TLC has been made on the same wind tunnel; the effect of heat conduction on film cooling was analyzed qualitatively and quantitatively. Sixteen cases were analyzed in which the mainstream Reynolds number was 35 000, 45 000, and 57 000; the blowing ratio was 0.5, 1.0, 1.5, and 2.0; and the density ratio was 0.91 and 1.44. We found that both PSP and TLC results exihibit an optimum blowing ratio under the condition of small and medium mainstream Reynolds numbers, but the measured film cooling efficiency is slightly different. Differences between PSP and TLC results were caused by the heat conduction of the substantial region. At the same time, a high mainstream Reynolds number and a high blowing ratio would boost heat conduction. Furthermore, in cases of high mainstream Reynolds number and low blowing ratio, the effect of heat conduction decreased obviously. When the blowing ratio is small as 0.5 and N2 acts as a coolant, PSP and TLC results match well, showing that in cases of low blowing ratio and low density ratio, the effect of heat conduction can be ignored.