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Chemical recycling of polyurethane (PU) waste is essential to displace the need for virgin polyol production and enable sustainable PU production. Currently, less than 20% of PU waste is downcycled through rebinding to lower value products than the original PU. Chemical recycling of PU waste often requires significant input of materials like solvents and slow reaction rates. Here, we report the fast (

[Objective] In order to explore the relationship between the windbreak direction and the prevailing wind erosion direction in the black soil region of Northeast China. [Methods] The basic characteristics of the windbreak in the study area were obtained by remote sensing interpretation and field survey, and the angle of intersection between the windbreak direction and the prevailing wind erosion direction, that is, the wind direction declination angle, was calculated and analyzed by combining the wind speed and wind direction data of 43 meteorological stations in the study area. [Results] The westerly wind in Mengdong black soil sub-region accounted for a large proportion, the wind direction was more concentrated, the prevailing wind erosion direction dominance was strong, the wind direction in the Songnen black soil sub-region was scattered, and the prevailing wind erosion direction dominance was weak. Average windbreak density Songnen black soil sub-area > Mengdong black soil sub-region; The windbreak direction accounted for the largest proportion in the Songnen black soil sub-area was the N-S trend windbreak direction, and there was no obvious regularity in the Mengdong black soil sub-region. In the study area, the proportion of wind declination angle 30° was 70.40%, and the wind protection effect was poor. [Conclusion] The direction of a large number of windbreak in the study area is oblique to the prevailing wind erosion direction, and the protective effect is poor. The results of this study have important reference value for understanding the density and trend of existing windbreak belts, and for further construction and transformation of windbreak.

We develop and demonstrate how to use the Graphical Unitary Group Approach (GUGA)-based MRCISD with Core–Valence Separation (CVS) approximation to compute the core-excited states. First, perform a normal Self-Consistent-Field (SCF) or valence MCSCF calculation to optimize the molecular orbitals. Second, rotate the optimized target core orbitals and append to the active space, form an extended CVS active space, and perform a CVS-MCSCF calculation for core-excited states. Finally, construct the CVS-MRCISD expansion space and perform a CVS-MRCISD calculation to optimize the CI coefficients based on the variational method. The CVS approximation with GUGA-based methods can be implemented by flexible truncation of the Distinct Row Table. Eliminating the valence-excited configurations from the CVS-MRCISD expansion space can prevent variational collapse in the Davidson iteration diagonalization. The accuracy of the CVS-MRCISD scheme was investigated for excitation energies and compared with that of the CVS-MCSCF and CVS-CASPT2 methods using the same active space. The results show that CVS-MRCISD is capable of reproducing well-matched vertical core excitation energies that are consistent with experiments by combining large basis sets and a rational reference space. The calculation results also highlight the fact that the dynamic correlation between electrons makes an undeniable contribution in core-excited states. [ABSTRACT FROM AUTHOR]

Elucidating the mechanism of soil erosion caused by extreme rainstorms could improve agroecosystems' resilience to the extreme climate. However, less attention has been paid to the regional difference of soil erosion during extreme rainstorms through multiple field investigations. Using six field surveys of extreme rainstorms, soil erosion and its driving mechanism were investigated on farmland in the Loess area and the Rocky mountain area. Conclusions are as follows: (1) Farmland was severely eroded in comparison with abandoned land and forest–grass land. The erosion modulus of farmland in the Loess area (51 606.51 t/km2) was greater than that in the Rocky mountain area (2582.75 t/km2). (2) In both the Loess area and the Rocky mountain area, the main erosion types on sloped cropland and terraced land were rills/gullies and embankment failure, respectively. Terracing is an appropriate measure that can effectively control farmland erosion in rainstorm events. (3) Concentrated flow is a major driver of soil erosion, with nearly all rills/gullies occurring in the flow paths. Drainage measures can prevent the formation of concentrated flow, weakening rills/gullies erosion in farmland. (4) Building bio‐embankment, planting high‐coverage crops, and implementing local protection measures could reduce the farmland erosion influenced by extremely heavy rainfall. Combining drainage and agronomic measures is the common strategy to combat extreme rainstorm events for reducing farmland erosion in the two regions. These results can be applied to improve the ability of agricultural systems to cope with extreme rainstorms. [ABSTRACT FROM AUTHOR]