具有独特三维框架结构的钠超离子导体型磷酸钒钠是非常具有前景的钠电正极材料。在本工作中,两种碳源被选择作为原材料,通过溶胶凝胶法制备了碳包覆的磷酸钒钠。深入研究了不同炭材料对晶体结构、形貌特征、动力学特性以及电化学储钠特...具有独特三维框架结构的钠超离子导体型磷酸钒钠是非常具有前景的钠电正极材料。在本工作中,两种碳源被选择作为原材料,通过溶胶凝胶法制备了碳包覆的磷酸钒钠。深入研究了不同炭材料对晶体结构、形貌特征、动力学特性以及电化学储钠特性的影响。结果表明柠檬酸作为碳源制备得到的磷酸钒钠,具有更大的晶胞体积和更小的粒子尺寸,导致了拓宽的离子迁移通道和缩短的离子迁移路径,进而提高动力学特性。该材料表现出优异的电化学特性,在0.1 C下可以释放112.3 mAh g^(−1)的容量。在1 C循环200圈下容量保持率接近100%。由于快速的粒子导电特性,在2 C和5 C的大倍率循环下,该材料可以释放90.0和89.1 mAh g^(−1)的初始容量,循环200圈后保持率分别为92.7%和90%。因此,这种改性的磷酸钒钠电极材料可以作为优异的正极材料应用在钠电池领域。展开更多
The Rana temporaria chensinensis is an amphibian distributing mainly over the north of China. Its skin gland contains a variety of peptides, including antibacterial peptides. One of them, component 1, has been pur...The Rana temporaria chensinensis is an amphibian distributing mainly over the north of China. Its skin gland contains a variety of peptides, including antibacterial peptides. One of them, component 1, has been purified from the dried skin of R.temporaria chensinesis using a five step procedure. Purified component 1 has a molecular weight of 5 700 and its amino acid composition shows that it is devoid of disulfide bridges but rich in histine and glycine residues. Moreover, it has been found that it has a broad spectrum of antibacterial activity for Pseuctomonas aeruginosa, Escherichia coli, Bacillus sublilis, S. faccalis and Proteus vulgaris .展开更多
AC motors, especially the squirrel cage induction motors have the advantages of simple structure, good reliability and low cost. They are more suitable to be used as electrical dynamometers to provide dynamic load for...AC motors, especially the squirrel cage induction motors have the advantages of simple structure, good reliability and low cost. They are more suitable to be used as electrical dynamometers to provide dynamic load for bench test systems. But, the speed and torque of induction motors are not easy to be controlled accurately. In this work, an electrical dynamometer based on the induction motor is proposed. In order to get better control performance of torque and speed of induction motor, an improved direct torque control method(DTC) is also developed based on the space vector modulation(SVM) technique. The performance of the proposed dynamometer system is validated in the Matlab/Simulink platform. The simulation results show that the new dynamometer has good torque and stator flux response. And the torque and stator current ripples of it are reduced significantly compared with using the conventional DTC method.展开更多
文摘具有独特三维框架结构的钠超离子导体型磷酸钒钠是非常具有前景的钠电正极材料。在本工作中,两种碳源被选择作为原材料,通过溶胶凝胶法制备了碳包覆的磷酸钒钠。深入研究了不同炭材料对晶体结构、形貌特征、动力学特性以及电化学储钠特性的影响。结果表明柠檬酸作为碳源制备得到的磷酸钒钠,具有更大的晶胞体积和更小的粒子尺寸,导致了拓宽的离子迁移通道和缩短的离子迁移路径,进而提高动力学特性。该材料表现出优异的电化学特性,在0.1 C下可以释放112.3 mAh g^(−1)的容量。在1 C循环200圈下容量保持率接近100%。由于快速的粒子导电特性,在2 C和5 C的大倍率循环下,该材料可以释放90.0和89.1 mAh g^(−1)的初始容量,循环200圈后保持率分别为92.7%和90%。因此,这种改性的磷酸钒钠电极材料可以作为优异的正极材料应用在钠电池领域。
基金Project(9140xx8020212xx) supported by the Advanced Research Foundation,ChinaProject(GZ2018KF003) supported by the State Key Laboratory of Smart Manufacturing for Special Vehicles and Transmission System,China
文摘The Rana temporaria chensinensis is an amphibian distributing mainly over the north of China. Its skin gland contains a variety of peptides, including antibacterial peptides. One of them, component 1, has been purified from the dried skin of R.temporaria chensinesis using a five step procedure. Purified component 1 has a molecular weight of 5 700 and its amino acid composition shows that it is devoid of disulfide bridges but rich in histine and glycine residues. Moreover, it has been found that it has a broad spectrum of antibacterial activity for Pseuctomonas aeruginosa, Escherichia coli, Bacillus sublilis, S. faccalis and Proteus vulgaris .
基金Project(SS2012AA04104)supported by High-tech Research and Development Program of China
文摘AC motors, especially the squirrel cage induction motors have the advantages of simple structure, good reliability and low cost. They are more suitable to be used as electrical dynamometers to provide dynamic load for bench test systems. But, the speed and torque of induction motors are not easy to be controlled accurately. In this work, an electrical dynamometer based on the induction motor is proposed. In order to get better control performance of torque and speed of induction motor, an improved direct torque control method(DTC) is also developed based on the space vector modulation(SVM) technique. The performance of the proposed dynamometer system is validated in the Matlab/Simulink platform. The simulation results show that the new dynamometer has good torque and stator flux response. And the torque and stator current ripples of it are reduced significantly compared with using the conventional DTC method.
