To investigate plant biomass and nutrient distribution and accumulation in organs of Alnus cremastogyne at different ages from 1 to 4 years, the biomass, N, P, K, Ca, Mg, Fe and Zn were tested. The results showed that...To investigate plant biomass and nutrient distribution and accumulation in organs of Alnus cremastogyne at different ages from 1 to 4 years, the biomass, N, P, K, Ca, Mg, Fe and Zn were tested. The results showed that the average biomass of the whole tree and the biomass of leaf, branch, stem, and root were in positive correlation with tree age, but the growth rate of biomass had a decreasing trend with the tree age increasing, and only the biomass proportion of the trunk in the whole individual plant showed an increasing trend with age. The contents of nutrient elements in organs showed an order of N 〉 Ca 〉 K 〉 Mg 〉 P 〉 Fe 〉 Zn ; and the contents of N, P and K were higher in the leaf than in other organs, and the contents of Ca, Mg and Fe in the root were higher than in other organs. The accumulations of N, P, K, Ca, Mg and Zn were the highest in the trunk, and that of Fe was the highest in the root. The annual net accumulations of N, P, K, Ca and Mg in the average trees from 1 to 4 years old were 17.07, 40.79, 95.82 and 106.71 g, respectively, and the annual net accumulations of microelements （Fe and Zn） were 335.04, 577.26, 1267 and 1525.27 mg, respectively.展开更多
The analysis of the eddy-current field in the wound core widely used in the field of transformer energy conservation is taken as the theme.Adopting the homogenisation idea to consider the unique geometry of the wound ...The analysis of the eddy-current field in the wound core widely used in the field of transformer energy conservation is taken as the theme.Adopting the homogenisation idea to consider the unique geometry of the wound core and features of its equivalent multi-stage circular cross-section magnetic boundary,a homogeneous model consisting of a columnar material with continuous homogeneous electromagnetic anisotropy is established by deriving the Maxwell equations of the magnetic quasi-static field in the columnar coordinate system.Finally,a homogeneous fine element model for the eddycurrent field in the wound core is established and the accuracy of the model has been verified by the test platform.The result shows that the homogeneous model can be effectively used for the analysis of the eddy-current field in the wound core,and the error of calculating the eddy-current loss under different excitation conditions is less than 6%under the premise of extremely saving the engineering calculation cost,which will help improve the operational performance of the wound core and contribute to the energysaving goal of the high-voltage equipment.展开更多
基金Supported by Project of Science and Technology Department in Sichuan Province(2016NZ0043)
文摘To investigate plant biomass and nutrient distribution and accumulation in organs of Alnus cremastogyne at different ages from 1 to 4 years, the biomass, N, P, K, Ca, Mg, Fe and Zn were tested. The results showed that the average biomass of the whole tree and the biomass of leaf, branch, stem, and root were in positive correlation with tree age, but the growth rate of biomass had a decreasing trend with the tree age increasing, and only the biomass proportion of the trunk in the whole individual plant showed an increasing trend with age. The contents of nutrient elements in organs showed an order of N 〉 Ca 〉 K 〉 Mg 〉 P 〉 Fe 〉 Zn ; and the contents of N, P and K were higher in the leaf than in other organs, and the contents of Ca, Mg and Fe in the root were higher than in other organs. The accumulations of N, P, K, Ca, Mg and Zn were the highest in the trunk, and that of Fe was the highest in the root. The annual net accumulations of N, P, K, Ca and Mg in the average trees from 1 to 4 years old were 17.07, 40.79, 95.82 and 106.71 g, respectively, and the annual net accumulations of microelements （Fe and Zn） were 335.04, 577.26, 1267 and 1525.27 mg, respectively.
基金National Natural Science Foundation of China under Grant,Grant/Award Number:U1834203Sichuan Science and Technology Program,Grant/Award Number:2020JDTD0009。
文摘The analysis of the eddy-current field in the wound core widely used in the field of transformer energy conservation is taken as the theme.Adopting the homogenisation idea to consider the unique geometry of the wound core and features of its equivalent multi-stage circular cross-section magnetic boundary,a homogeneous model consisting of a columnar material with continuous homogeneous electromagnetic anisotropy is established by deriving the Maxwell equations of the magnetic quasi-static field in the columnar coordinate system.Finally,a homogeneous fine element model for the eddycurrent field in the wound core is established and the accuracy of the model has been verified by the test platform.The result shows that the homogeneous model can be effectively used for the analysis of the eddy-current field in the wound core,and the error of calculating the eddy-current loss under different excitation conditions is less than 6%under the premise of extremely saving the engineering calculation cost,which will help improve the operational performance of the wound core and contribute to the energysaving goal of the high-voltage equipment.
