In the process of changes in total population, structure, and spatial distribution, it is essential to investigate the inner rules of the harmonious correlation between population and development. Thus, this study examines the correlation between demographic variables (e.g., delayed retirement, total fertility rate, and life expectancy) and economic development in China based on the overlapping generations (OLG) model and numerical simulation method. The findings reveal the following: (1) total social output level positively correlates with survival probability; (2) the contribution of the aging labor force (retirement age delay) to the total output is significant and an essential source of sustainable economic growth; (3) aggregate output increases first and then decreases with the increase in individual pension contributions rate, and the correlation between the two is a ∩-shaped curve. The policy implications of this study are that China’s economic transformation is a general trend, which should promote the upgrading of the demographic dividend from quantitative type to qualitative type and tap the human capital potential to increase the capital-based demographic dividend and activate the gender dividend.

Based on the actual hot zone structure of an AlN crystal growth resistance furnace, the global numerical simulation on the heat transfer process in the AlN crystal growth was performed. The influence of different heater structures on the growth of AlN crystals was investigated. It was found that the top heater can effectively reduce the axial temperature gradient, and the side heater 2 has a similar effect on the axial gradient, but the effect feedback is slightly weaker. The axial temperature gradient tends to increase when the bottom heater is added to the furnace, and the adjustable range of the axial temperature gradient of the side 1 heater + bottom heater mode is the largest. Our work will provide important reference values for AlN crystal growth by the resistance method.