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The Mg–Gd–Y–Zn–Zr alloy containing a long period stacking ordered (LPSO) phase was subjected to multi-pass deformation by means of a multi-directional forging process, and the microstructure evolution and the influence of the LPSO phase on its dynamic recrystallization (DRX) were studied. The results showed that multi-directional forging can effectively refine the grain with the DRX fraction increased, and DRXed grains lead to the decrease of the texture intensity, which can significantly improve the mechanical properties of the alloy. The different morphologies of the LPSO phase have different degrees of promotion relative to DRX behavior. The lamellar LPSO phase with kinks promoted dislocation plugging, where there could be a potential nucleation site for DRX grains. The fragmented lamellar LPSO phase promoted the DRX process through the particle-stimulated nucleation mechanism, and the block-shaped phase was more prone to stress concentration, which promoted DRX. These effects resulted in continuous grain refinement and a more uniform microstructure. [ABSTRACT FROM AUTHOR]

• Constructed a comprehensive evaluation model of urban ventilation potential (UVP) • UVP has a negative correlation with Land Surface Temperature (LST) • Circuit theory is more suitable for the identification of ventilation corridors. • Ventilation corridors have seasonal differences in mitigating LST. In the context of global warming and rapid urbanization, urban wind-heat environment has become increasingly prominent. Although the identification of ventilation corridors has been well investigated, the impact of ventilation corridors on thermal environment remains unclear. Here, we use the single-window algorithm and circuit theory method to analyze the characteristics of land surface temperature (LST) and ventilation corridors in four megacities of China, so as to quantify the effect of ventilation corridors on thermal environment. Results show that circuit theory works well for identifying ventilation corridors. Moreover, we find that spatial distribution of ventilation corridors in one city is remarkably different from another. Interestingly, ventilation corridors, which consist of green spaces, waters, and roads, have a remarkable mitigation effect on thermal environment. LST of each city is mitigated by 2.39 ℃, 3.22 ℃, 2.11 ℃ and 2.60 ℃, respectively, and the cooling intensity in summer is better than that in winter. Thus, it is of great significance to arrange urban form and ventilation corridors to alleviate the impact of high temperature on urban residents. [ABSTRACT FROM AUTHOR]

Urbanization is a complex process that covers a wide range of topics, of which population, industry and land urbanization are three important aspects. Jilin Province is an important agricultural province in China. The contradiction between population, industry and land urbanization is especially prominent here, and its coupling development is of great practical significance. In this paper, the coupling degree of population-industry-land urbanization in Jilin Province in 1990, 2000 and 2010 is measured by coupling mode. The spatial pattern of the coupling degree is analyzed by trend surface analysis and global and local spatial autocorrelation. The influence factors and their spatial differentiation are discussed using multiple linear regression (MLR) model and geographic weighted regression (GWR) model. The results show that: 1) the coupling degree of population-industry-land urbanization in Jilin Province is at a low level. Judging from the change of time scale, the urbanization of most research units is becoming more and more coordinated. From the comparison of spatial scales, there is significant spatial difference in the research units of different administrative levels. 2) Judging from the global change trend, the coupling degree of population-industry-land urbanization in the central region is higher than that in western and eastern regions. The coordination of urbanization in the central region is relatively good, and the distribution of the cold and hot spots is basically the same as that overall. 3) The spatial pattern of the coupling degree is related to the cold and hot spot distribution of the influence coefficient of urban population density and per capita urban construction land. The variation of the coupling degree spatial pattern is synchronous with the spatial change of the urban population density influence coefficient. 4) The degree of agglomeration of the urban population is the main factor promoting the coupling pattern of population-industry-land urbanization in Jilin Province, and the extent of its influence is gradually increasing. In addition, the level of city administrative, the efficiency of urban expansion and the capacity of market consumption also have an important influence on the coupling pattern. [ABSTRACT FROM AUTHOR]

Based on the repetitive upsetting-extrusion (RUE) process, the evolution of the LPSO phase and its effect on the dynamic recrystallization (DRX) of Mg-9Gd-4Y–2Zn-0.5Zr (wt%) alloy during the multi-pass deformation were studied. The results showed that with the increase of RUE processing, the DRX fraction gradually increased, the grains were effectively refined, and the texture was weakened. The lamellar LPSO phase mainly underwent mechanical crushing, bending, tearing, and kinking to become refinement. The block-shaped LPSO phases dissolved during the deformation process, forming a stripe-like structure, and its rest of the refinement mechanism was similar to the lamellar phase. The refinement of block-shaped phase was slower than that of lamellar phase. However, the block-shaped phases always promoted DRX through the PSN mechanism, while the lamellar phases with a large volume inhibited the generation of DRX. After the refinement of lamellar phases, the inhibition effect was transformed into the promotion effect, which leaded to a continuous increase in the DRX fraction. This further promoted the uniform distribution of the LPSO phases and obtained a more ideal microstructure. • Repetitive upsetting-extrusion and DRX refined microstructure and weakened texture. • LPSO phases mainly refined by mechanical crushing, bending, tearing, and kinking. • The block-shaped phases dissolved to a stripe-like structure, promoting refinement. • Refined lamellar phases promoted DRX while large lamellar phases inhabited DRX. [ABSTRACT FROM AUTHOR]