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High-quality development efficiency can comprehensively measure the development quality of a region. This study constructed the SE-SBM Model and measured the quality development efficiency of the Yellow River Basin from 2010 to 2019. In panel regression, the periodic effects of industrial structure, environmental regulation, and their interaction terms on the efficiency of high-quality development are analyzed. From the perspective of the threshold effect, we explore the possible threshold of interaction to change the efficiency of high-quality development. The results show: (1) From 2010 to 2019, the high-quality development efficiency of the Yellow River Basin’s watershed segment showed a gradient development trend. (2) In panel regression, the interaction terms positively impact the whole basin’s high-quality development efficiency. However, for different sub-basins, the impact of the core explanatory variable on the efficiency of high-quality development is different. (3) The Yellow River basin has a single significant threshold in the threshold regression. From the perspective of the sub-basin, the upper and lower reaches of the Yellow River have a single significant threshold. There is no threshold in midstream. Based on the research results, the article puts forward relevant suggestions, such as reasonably improving regional imports and exports and introducing high-quality foreign capital, which can provide a basis for relevant departments.

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The emission characteristics of a model centrally staged lean premixed prevaporized (LPP) combustor was investigated under near-critical and supercritical main fuel injections. The Chinese aviation kerosene, RP-3, with its critical temperature and pressure of 651 K and 2.35 MPa, was preheated from 500 to 740 K and pressurized from 2.0 to 3.5 MPa before being injected into the combustor. The combustor liner consists of ceramic matrix composites (CMC), which are installed on a water-cooling frame. Therefore, the combustor features a high dome air ratio (95% of the total air) by removing both primary and dilution holes and redirecting the liner cooling air to the dome. The overall fuel-to-air ratio was varied from 0.030 to 0.053. The emissions at the combustor outlet were measured at various operating conditions in the range of inlet air temperatures from 600 to 840 K and pressures from 2.0 to 2.8 MPa. The results showed that EINOx decreases about 40% as the injection temperature increase from 500 K to 740 K at 2.0 to 2.4 MPa injection pressure. It indicates that the transition from liquid fuel to supercritical fuel drastically reduces fuel density and surface tension. Increasing injection fuel temperature significantly improves the fuel/air mixing and avoids hot spot formation that favors NOx formation. Both EICO and EIUHC decrease slightly with increasing fuel injection temperature, suggesting a weak relation between the combustion efficiency and fuel thermodynamic state. The finding of the current study suggests that the NOx emissions are affected by the premixing quality of the main injector and may be reduced by injecting supercritical kerosene.