The MnZn ferrite coating formed on the surface of iron-based soft magnetic powders via facile and modified sol–gel process has been fabricated to obtain better magnetic performance due to its higher permeability comp...The MnZn ferrite coating formed on the surface of iron-based soft magnetic powders via facile and modified sol–gel process has been fabricated to obtain better magnetic performance due to its higher permeability compared with traditional nonmagnetic insulation coatings. The influence of the MnZn ferrite contents on the magnetic performance of the soft magnetic composites(SMCs) has been studied. As the MnZn insulation content increases, the core loss first experiences a decreasing trend that is followed by progressive increase, while the permeability follows an increasing trend and subsequently degrades. The optimized magnetic performance is achieved with 2.0 wt% MnZn ferrite, which results from the decrement of inter-particle eddy current losses based on loss separation. A uniform and compact coating layer composed of MnZn ferrite and oxides with an average thickness of 0.38 ± 0.08 μm is obtained by utilizing ion beam technology, and the interface between the powders and the coating shows satisfied adhesiveness compared with the sample directly prepared by mechanical mixing. The evolution of the coating layers during the calcination process has been presented based on careful analysis of the composition and microstructure.展开更多
Taxonomy plays an important role in understanding the origin, evolution, and ecological functionality of biodiversity. There are large number of unknown species yet to be described by taxonomists, which together with ...Taxonomy plays an important role in understanding the origin, evolution, and ecological functionality of biodiversity. There are large number of unknown species yet to be described by taxonomists, which together with their ecosystem services cannot be effectively protected prior to description. Despite this, taxonomy has been increasingly underrated insufficient funds and permanent positions to retain young talents. Further, the impact factordriven evaluation systems in China exacerbate this downward trend, so alternative evaluation metrics are urgently necessary. When the current generation of outstanding taxonomists retires,there will be too few remaining taxonomists left to train the next generation. In light of these challenges, all co-authors worked together on this paper to analyze the current situation of taxonomy and put out a joint call for immediate actions to advance taxonomy in China.展开更多
Dear editor,Polymorphism refers to two or more clearly different phenotypes coexisting in the population of a species. It has been observed and studied among ants, bees, wasps, termites,dung beetles and stag beetles (...Dear editor,Polymorphism refers to two or more clearly different phenotypes coexisting in the population of a species. It has been observed and studied among ants, bees, wasps, termites,dung beetles and stag beetles (Trible and Kronauer, 2017;Zhao et al., 2019). Size and shape variation of these holometabolic insects, especially ants, usually happen in larval development rather than adult stage.展开更多
基金Project supported by the Natural Science Foundation of Shandong Province,China(Grant No.ZR2018MEM020)
文摘The MnZn ferrite coating formed on the surface of iron-based soft magnetic powders via facile and modified sol–gel process has been fabricated to obtain better magnetic performance due to its higher permeability compared with traditional nonmagnetic insulation coatings. The influence of the MnZn ferrite contents on the magnetic performance of the soft magnetic composites(SMCs) has been studied. As the MnZn insulation content increases, the core loss first experiences a decreasing trend that is followed by progressive increase, while the permeability follows an increasing trend and subsequently degrades. The optimized magnetic performance is achieved with 2.0 wt% MnZn ferrite, which results from the decrement of inter-particle eddy current losses based on loss separation. A uniform and compact coating layer composed of MnZn ferrite and oxides with an average thickness of 0.38 ± 0.08 μm is obtained by utilizing ion beam technology, and the interface between the powders and the coating shows satisfied adhesiveness compared with the sample directly prepared by mechanical mixing. The evolution of the coating layers during the calcination process has been presented based on careful analysis of the composition and microstructure.
基金mainly supported by National Science Fund for Distinguished Young Scholars (31625024)a grant (2008DP173354) from the Key Laboratory of the Zoological Systematics and Evolution of the Chinese Academy of Sciences。
文摘Taxonomy plays an important role in understanding the origin, evolution, and ecological functionality of biodiversity. There are large number of unknown species yet to be described by taxonomists, which together with their ecosystem services cannot be effectively protected prior to description. Despite this, taxonomy has been increasingly underrated insufficient funds and permanent positions to retain young talents. Further, the impact factordriven evaluation systems in China exacerbate this downward trend, so alternative evaluation metrics are urgently necessary. When the current generation of outstanding taxonomists retires,there will be too few remaining taxonomists left to train the next generation. In light of these challenges, all co-authors worked together on this paper to analyze the current situation of taxonomy and put out a joint call for immediate actions to advance taxonomy in China.
基金supported by the National Natural Science Foundation of China (31730087, 41688103 and 31872277)the Program for Changjiang Scholars and Innovative Research Team in University (IRT-17R75)+1 种基金the Support Project of High-level Teachers in Beijing Municipal Universities in the Period of 13th Five-year Plan (IDHT20180518)the Beijing Natural Science Foundation (5182004)。
文摘Dear editor,Polymorphism refers to two or more clearly different phenotypes coexisting in the population of a species. It has been observed and studied among ants, bees, wasps, termites,dung beetles and stag beetles (Trible and Kronauer, 2017;Zhao et al., 2019). Size and shape variation of these holometabolic insects, especially ants, usually happen in larval development rather than adult stage.