Birefringent materials possess significant optical anisotropy,making them pivotal in modulating light polarization,particularly in laser technology and scientific applications.In this study,five variants of antimony p...Birefringent materials possess significant optical anisotropy,making them pivotal in modulating light polarization,particularly in laser technology and scientific applications.In this study,five variants of antimony potassium fluoronitrates named SbF_(3)·KNO_(3)(1),SbF_(3)·3KNO_(3)(2),SbF_(3)·3KSbF_(4)·KNO_(3)(3),KSb_(2)F_(7)·3KNO_(3)(4),and KSb_(2)F_(7)·2KNO_(3)(5)were obtained.Remarkably,each compound contains distinct Sb-polyhedra configurations.Compounds 1 and 2 consist of singular[SbF_(3)]units,compound 3 harbors a mixture of[SbF_(3)]and[SbF_(4)]units,while compounds 4 and 5 feature single[SbF_(4)]units.Interestingly,the birefringence escalates progressively from 1 to 5,and notably,compound 5 exhibits the most pronounced birefringence among all reported inorganic antimony oxysalts.Detailed structural and property analyses affirm that the structural variance among the five compounds underpins the observed differences in birefringence.Moreover,the synergistic interplay between planarπ-conjugated NO_(3)^(−)groups and Sb^(3+)ions with lone-pair electrons facilitates the emergence of substantial polarization anisotropy.展开更多
Based on the numerical simulation analysis, structure parameters of the high pressure fuel pump and common rail as well as flow limiter are designed and the GD-1 high pressure common rail fuel injection system is self...Based on the numerical simulation analysis, structure parameters of the high pressure fuel pump and common rail as well as flow limiter are designed and the GD-1 high pressure common rail fuel injection system is self-developed. Fuel injection characteristics experiment is performed on the GD-1 system. And double-factor variance analysis is applied to investigate the influence of the rail pressure and injection pulse width on the consistency of fuel injection quantity, thus to test whether the design of structure parameters is sound accordingly. The results of experiment and test show that rail pressure and injection pulse width as well as their mutual-effect have no influence on the injection quantity consistency, which proves that the structure parameters design is successful and performance of GD-1 system is sound.展开更多
Tree height (H) in a natural stand or forest plantation is a fundamental variable in management, and the use of mathematical expressions that estimate H as a function of diameter at breast height (d) or variables at t...Tree height (H) in a natural stand or forest plantation is a fundamental variable in management, and the use of mathematical expressions that estimate H as a function of diameter at breast height (d) or variables at the stand level is a valuable support tool in forest inventories. The objective was to fit and propose a generalized H-d model for Pinus montezumae and Pinus pseudostrobus established in forest plantations of Nuevo San Juan Parangaricutiro, Michoacan, Mexico. Using nonlinear least squares (NLS), 10 generalized H-d models were fitted to 883 and 1226 pairs of H-d data from Pinus montezumae and Pinus pseudostrobus, respectively. The best model was refitted with the maximum likelihood mixed effects model (MEM) approach by including the site as a classification variable and a known variance structure. The Wang and Tang equation was selected as the best model with NLS;the MEM with an additive effect on two of its parameters and an exponential variance function improved the fit statistics for Pinus montezumae and Pinus pseudostrobus, respectively. The model validation showed equality of means among the estimates for both species and an independent subsample. The calibration of the MEM at the plot level was efficient and might increase the applicability of these results. The inclusion of dominant height in the MEM approach helped to reduce bias in the estimates and also to better explain the variability among plots.展开更多
基金supported by the National Natural Science Foundation of China(Nos.22122106,22071158,22375139,22305166).
文摘Birefringent materials possess significant optical anisotropy,making them pivotal in modulating light polarization,particularly in laser technology and scientific applications.In this study,five variants of antimony potassium fluoronitrates named SbF_(3)·KNO_(3)(1),SbF_(3)·3KNO_(3)(2),SbF_(3)·3KSbF_(4)·KNO_(3)(3),KSb_(2)F_(7)·3KNO_(3)(4),and KSb_(2)F_(7)·2KNO_(3)(5)were obtained.Remarkably,each compound contains distinct Sb-polyhedra configurations.Compounds 1 and 2 consist of singular[SbF_(3)]units,compound 3 harbors a mixture of[SbF_(3)]and[SbF_(4)]units,while compounds 4 and 5 feature single[SbF_(4)]units.Interestingly,the birefringence escalates progressively from 1 to 5,and notably,compound 5 exhibits the most pronounced birefringence among all reported inorganic antimony oxysalts.Detailed structural and property analyses affirm that the structural variance among the five compounds underpins the observed differences in birefringence.Moreover,the synergistic interplay between planarπ-conjugated NO_(3)^(−)groups and Sb^(3+)ions with lone-pair electrons facilitates the emergence of substantial polarization anisotropy.
文摘Based on the numerical simulation analysis, structure parameters of the high pressure fuel pump and common rail as well as flow limiter are designed and the GD-1 high pressure common rail fuel injection system is self-developed. Fuel injection characteristics experiment is performed on the GD-1 system. And double-factor variance analysis is applied to investigate the influence of the rail pressure and injection pulse width on the consistency of fuel injection quantity, thus to test whether the design of structure parameters is sound accordingly. The results of experiment and test show that rail pressure and injection pulse width as well as their mutual-effect have no influence on the injection quantity consistency, which proves that the structure parameters design is successful and performance of GD-1 system is sound.
文摘Tree height (H) in a natural stand or forest plantation is a fundamental variable in management, and the use of mathematical expressions that estimate H as a function of diameter at breast height (d) or variables at the stand level is a valuable support tool in forest inventories. The objective was to fit and propose a generalized H-d model for Pinus montezumae and Pinus pseudostrobus established in forest plantations of Nuevo San Juan Parangaricutiro, Michoacan, Mexico. Using nonlinear least squares (NLS), 10 generalized H-d models were fitted to 883 and 1226 pairs of H-d data from Pinus montezumae and Pinus pseudostrobus, respectively. The best model was refitted with the maximum likelihood mixed effects model (MEM) approach by including the site as a classification variable and a known variance structure. The Wang and Tang equation was selected as the best model with NLS;the MEM with an additive effect on two of its parameters and an exponential variance function improved the fit statistics for Pinus montezumae and Pinus pseudostrobus, respectively. The model validation showed equality of means among the estimates for both species and an independent subsample. The calibration of the MEM at the plot level was efficient and might increase the applicability of these results. The inclusion of dominant height in the MEM approach helped to reduce bias in the estimates and also to better explain the variability among plots.
