The bare LiFePO4 and LiFePO4/C composites with network structure were prepared by solid-state reaction. The crystalline structures, morphologies and specific surface areas of the materials were investigated by X-ray d...The bare LiFePO4 and LiFePO4/C composites with network structure were prepared by solid-state reaction. The crystalline structures, morphologies and specific surface areas of the materials were investigated by X-ray diffractometry(XRD), scanning electron microscopy(SEM) and multi-point brunauer emmett and teller(BET) method. The results show that the LiFePO4/C composite with the best network structure is obtained by adding 10% phenolic resin carbon. Its electronic conductivity increases to 2.86×10-2 S/cm. It possesses the highest specific surface area of 115.65 m2/g, which exhibits the highest discharge specific capacity of 164.33 mA·h/g at C/10 rate and 149.12 mA·h/g at 1 C rate. The discharge capacity is completely recovered when C/10 rate is applied again.展开更多
Tai’an City is rich in tourism resources,and there are many A-class tourist attractions.Based on the functions and characteristics of geographic information system(GIS),as well as the spatial distribution characteris...Tai’an City is rich in tourism resources,and there are many A-class tourist attractions.Based on the functions and characteristics of geographic information system(GIS),as well as the spatial distribution characteristics and distribution structure of tourist attractions,the research methods of nearest-neighbor distance,connectivity,accessibility and closeness analysis are used to analyze road traffi c distribution between tourist attractions in Tai’an City.①The R value of the nearest-neighbor point is 0.27,which proves that tourist attractions in Tai’an City are in the state of clustering,and the spatial distance of tourist attractions in clustering area is small.②Theβindex andγindex of connectivity are 1.42 and 0.58,respectively,indicating that the traffi c network connectivity between tourist attractions is low,there is no dense traffi c network,and the optimal combination of tourism resources in tourist attractions is not high.③The accessibility index Ai is 37.68 km,indicating that the accessibility is low and the traffi c between tourist attractions is not perfect.The research results will provide the reference for scientifi c,systematic and objective comprehensive evaluation of existing A-class scenic areas and traffi c conditions in Tai’an City.展开更多
The Tianlian 1-03 satellite, the third geosynchronous data relay satellite of China, was successfully launched into space on a LM-3C launch vehicle from the Xichang Satellite Launch Center at 23:43 Beijing time on Jul...The Tianlian 1-03 satellite, the third geosynchronous data relay satellite of China, was successfully launched into space on a LM-3C launch vehicle from the Xichang Satellite Launch Center at 23:43 Beijing time on July 25. Twenty-six minutes after the liftoff, the satellite展开更多
With the sharp increase of China＇s in-orbit spacecraft and the constraint TT＆C resources, a mathematical model for optimal TT＆C resource allocation is proposed, and the TT＆C facility remote monitoring function is ...With the sharp increase of China＇s in-orbit spacecraft and the constraint TT＆C resources, a mathematical model for optimal TT＆C resource allocation is proposed, and the TT＆C facility remote monitoring function is designed to achieve the multitask operation pattern under the unified management of the network management center. With this pattern, the TT＆C network management and the spacecraft management are separated, which is quite different from the previous pattern. Further, a novel spacecraft TT＆C technique based on spacecraft control language is developed, and the telecommanding pattern is designed to address the spacecraft operation problems. The engineering application shows that this pattern fundamentally improves the TT＆C network capability, increases the resource efficiency, and satisfies the efficient, accurate, and flexible operation of spacecraft.展开更多
基金Project(50672024) supported by the National Natural Science Foundation of ChinaProject(06FJ2006) supported by the Applied Basic Research of Hunan Province, China
文摘The bare LiFePO4 and LiFePO4/C composites with network structure were prepared by solid-state reaction. The crystalline structures, morphologies and specific surface areas of the materials were investigated by X-ray diffractometry(XRD), scanning electron microscopy(SEM) and multi-point brunauer emmett and teller(BET) method. The results show that the LiFePO4/C composite with the best network structure is obtained by adding 10% phenolic resin carbon. Its electronic conductivity increases to 2.86×10-2 S/cm. It possesses the highest specific surface area of 115.65 m2/g, which exhibits the highest discharge specific capacity of 164.33 mA·h/g at C/10 rate and 149.12 mA·h/g at 1 C rate. The discharge capacity is completely recovered when C/10 rate is applied again.
基金Natural Science Foundation of Shandong Province,China(ZR2019MD031)Philosophy and Social Science Planning Project of Tai’an City(2020skx035).
文摘Tai’an City is rich in tourism resources,and there are many A-class tourist attractions.Based on the functions and characteristics of geographic information system(GIS),as well as the spatial distribution characteristics and distribution structure of tourist attractions,the research methods of nearest-neighbor distance,connectivity,accessibility and closeness analysis are used to analyze road traffi c distribution between tourist attractions in Tai’an City.①The R value of the nearest-neighbor point is 0.27,which proves that tourist attractions in Tai’an City are in the state of clustering,and the spatial distance of tourist attractions in clustering area is small.②Theβindex andγindex of connectivity are 1.42 and 0.58,respectively,indicating that the traffi c network connectivity between tourist attractions is low,there is no dense traffi c network,and the optimal combination of tourism resources in tourist attractions is not high.③The accessibility index Ai is 37.68 km,indicating that the accessibility is low and the traffi c between tourist attractions is not perfect.The research results will provide the reference for scientifi c,systematic and objective comprehensive evaluation of existing A-class scenic areas and traffi c conditions in Tai’an City.
文摘The Tianlian 1-03 satellite, the third geosynchronous data relay satellite of China, was successfully launched into space on a LM-3C launch vehicle from the Xichang Satellite Launch Center at 23:43 Beijing time on July 25. Twenty-six minutes after the liftoff, the satellite
基金supported by the China Postdotoral Science Foundation (20060401004).
文摘With the sharp increase of China＇s in-orbit spacecraft and the constraint TT＆C resources, a mathematical model for optimal TT＆C resource allocation is proposed, and the TT＆C facility remote monitoring function is designed to achieve the multitask operation pattern under the unified management of the network management center. With this pattern, the TT＆C network management and the spacecraft management are separated, which is quite different from the previous pattern. Further, a novel spacecraft TT＆C technique based on spacecraft control language is developed, and the telecommanding pattern is designed to address the spacecraft operation problems. The engineering application shows that this pattern fundamentally improves the TT＆C network capability, increases the resource efficiency, and satisfies the efficient, accurate, and flexible operation of spacecraft.
