Research objectives: This paper discusses how to support the realization of carbon peak and carbon neutrality through the optimization of national spatial structures by establishing a relationship model between land-use structure and carbon emissions, and then provide theoretical and methodological support for the formulation of relevant policies and plans, as well as the evaluation of implementation effects. Research methods: grid analysis, GIS spatial analysis, double log linear regression model. Results: There is a strong correlation between the spatial structure of land and carbon emissions; the scale of construction land, especially industrial land, directly affects carbon emissions; if the area of construction land is doubled, CO2 emissions will increase by about 1.7 times. Conclusions: The potential of controlling carbon emission intensity through land structure at the urban level is great, and it is feasible to control carbon emission intensity through territorial spatial planning system. The control elements can be divided into the following levels: land supply control, land structure adjustment, land intensity constraint, and function adjustment of existing land.
This paper concerns a new method for projectile disposal by emptying the explosives in projectiles with electromagnetic heating. It explains the basic principles of the emptying technology via electromagnetic heating. A multiphysical analysis model coupled with an electromagnetic, thermal, fluid and phase transition model is established, and the explosive melting simulation is conducted based on this model. The dynamic phase transition process of the explosive from solid to liquid is simulated, and the electric field, magnetic field and thermal field distribution characteristics during the process are analyzed. Furthermore, the effect of excitation current characteristics on the phase transition of the explosive is given, which shows that the explosive melting process is controllable by setting the excitation current amplitude or frequency. This paper provides a new method for the disposal of end-of-life projectiles, which is more controllable, safe and environmentally friendly.
The excitation pulse current used to drive the railgun needs to present very a high magnitude (hundreds of kA) flat-top with very low ripple. At present, the main method to obtain this current is to increase the number of the capacitive pulsed power supply (PPS) modules. However, low utilization and massive volume of the railgun system would occur with this method, hampering the application of railgun. Therefore, the utilization optimization technology of PPS is researched in this paper. In order to obtain highly stable flat-top current, the control strategy of the capacitive PPS is designed, and a new charging voltage configuration is proposed, which significantly decreases the use of the capacitive modules. Besides, a miniaturization transformation scheme of capacitive PPS is proposed based on the control strategy. The result shows that the flat-top current ripple has the biggest influence on the PPS utilization, and the smaller the flat-top current ripple, the lower the utilization. When the current with 200 kA magnitude and 0.75% flat-top current ripple is achieved, an 81.9% decrease of volume and a 428.7% utilization improvement are achieved through miniaturization transformation.
As to the countermeasures of low, small and slow "black flying" UAV, the flying net launching technology scheme for anti-UAV based on reluctance electromagnetic launcher was proposed, and the working principle of the system was analyzed. For the nonlinear large deformation problem of flying net, the default beam element model and mechanical model of flying net were constructed, and the simulation analysis was carried out. Based on the orthogonal experimental method, the optimization analysis of flying net parameters was carried out, and based on the range analysis results, the sensitivity of armature initial velocity, armature mass and initial angle to the effective distance of flying net was obtained, as well as the optimization parameter combination. The flying net launching experimental system was established and validation experiments were carried out. The results show that the reluctance electromagnetic launching technology can be used to launch the flying net, and the flying net can effectively intercept the UAV. Furthermore, the initial angle of the armature has the greatest influence on the effective distance of the flying net, while the velocity of the armature has the least influence.
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