To improve the machining efficiency of large symmetrical freeform surface, this paper proposes a new machining method： symmetrical machining （SM）. Based on the concept of collision avoidance plane （CAP）, collisio...To improve the machining efficiency of large symmetrical freeform surface, this paper proposes a new machining method： symmetrical machining （SM）. Based on the concept of collision avoidance plane （CAP）, collisions among cutters or headstocks are avoided, and the area of machining residue is controlled effectively. Machining residue is eliminated due to proper design of symmetrical tool in mechanism and control project. Taking 5-axis symmetrical machine with columnar headstocks and flat cutters as example, this paper proposes collision avoidance algorithm. Finally, using a twin-skeg ship model surface as an example, the method is applied to avoiding collisions in original tool path. Simulation and real machining results show that the scheme is practical. Furthermore, the machining efficiency of SM is improved 85% more than that of the traditional single cutter technology.展开更多
As the information on telecommunication products updates rapidly, using E-learning in staff training becomes an edge for company operation. However, previous studies showed that staff＇s attitude toward E-learning sig...As the information on telecommunication products updates rapidly, using E-learning in staff training becomes an edge for company operation. However, previous studies showed that staff＇s attitude toward E-learning significantly affected the outcomes of training. The purpose of this study is to investigate the acceptance of E-learning in a telecommunication company. The researchers adopted the technology acceptance model （TAM） and diffusion of innovation theory to evaluate the perceived usefulness and perceived ease of use on E-learning, in addition to employees＇ self-directed learning motivation, attitude toward computers, and organizational influence. We randomly chose 571 employees of the telecommunication entrepreneur at the Taichung office in Taiwan to participate in this survey. The result showed that employees＇ background factors such as age, job position, marital status, education level and the scale of job unit had the significant impact on behavioral intention to use E-learning. Employees＇ self-directed learning, attitude toward computers, and organizational influence respectively also had positive effects on perceived usefulness of E-learning and perceived ease of use of E-learning. Furthermore, employees＇ perceived usefulness of E-learning and perceived ease of use of E-learning also had a positive effect on behavioral intention to use E-learning systems.展开更多
Electrospinning is firstly used to one-pot synthesis of Li3VO4@C nanofibers in a large scale. Although with the presence of organic sources in synthesis process, the pure phase Li3VO4 with superior nanofibrous morphol...Electrospinning is firstly used to one-pot synthesis of Li3VO4@C nanofibers in a large scale. Although with the presence of organic sources in synthesis process, the pure phase Li3VO4 with superior nanofibrous morphology is still successfully obtained through adjusting different heat treatment processes and different vanadium sources. The prepared Li3VO4@C nanofibers exhibit a unique structure in which nanosized Li3VO4 particles are uniformly embedded in amorphous carbon matrix. Compared with LiBVO4/C powder, Li3VO4@C nanofibers display enhanced reversible capacity of 451 mAhg^-1 at 40mAg^-1 with an increased initial coulombic efficiency of 82.3%, and the capacity can remain at 394 mAh g ^-1 after 100 cycles. This superior electrochemical performance can be attributed to its unique structure which ensures a high reactivity by nanosized Li3VO4, more stable electrode/electrolyte interface by carbon encapsulation, improved electronic conductivity and buffered volume changes by flexible carbon matrix. The electrospinning technology provides an effective method to obtain high performance Li3VO4 as a promising anode material for lithium-ion batteries.展开更多
基金Project supported by the National Basic Research Program of China (Grant No.2005CB724100)
文摘To improve the machining efficiency of large symmetrical freeform surface, this paper proposes a new machining method： symmetrical machining （SM）. Based on the concept of collision avoidance plane （CAP）, collisions among cutters or headstocks are avoided, and the area of machining residue is controlled effectively. Machining residue is eliminated due to proper design of symmetrical tool in mechanism and control project. Taking 5-axis symmetrical machine with columnar headstocks and flat cutters as example, this paper proposes collision avoidance algorithm. Finally, using a twin-skeg ship model surface as an example, the method is applied to avoiding collisions in original tool path. Simulation and real machining results show that the scheme is practical. Furthermore, the machining efficiency of SM is improved 85% more than that of the traditional single cutter technology.
文摘As the information on telecommunication products updates rapidly, using E-learning in staff training becomes an edge for company operation. However, previous studies showed that staff＇s attitude toward E-learning significantly affected the outcomes of training. The purpose of this study is to investigate the acceptance of E-learning in a telecommunication company. The researchers adopted the technology acceptance model （TAM） and diffusion of innovation theory to evaluate the perceived usefulness and perceived ease of use on E-learning, in addition to employees＇ self-directed learning motivation, attitude toward computers, and organizational influence. We randomly chose 571 employees of the telecommunication entrepreneur at the Taichung office in Taiwan to participate in this survey. The result showed that employees＇ background factors such as age, job position, marital status, education level and the scale of job unit had the significant impact on behavioral intention to use E-learning. Employees＇ self-directed learning, attitude toward computers, and organizational influence respectively also had positive effects on perceived usefulness of E-learning and perceived ease of use of E-learning. Furthermore, employees＇ perceived usefulness of E-learning and perceived ease of use of E-learning also had a positive effect on behavioral intention to use E-learning systems.
基金supported by the National Natural Science Foundation of China (21571073, 51302099, 51472097)the Ministry of Science and Technology of China (2015CB932600)+2 种基金the Hubei Provincial Natural Science Foundation (2016CFA031)the Program for Huazhong University of Science and Technology (HUST) Interdisciplinary Innovation Team (2015ZDTD038)the Fundamental Research Funds for the Central University (2017KFKJXX007)
文摘Electrospinning is firstly used to one-pot synthesis of Li3VO4@C nanofibers in a large scale. Although with the presence of organic sources in synthesis process, the pure phase Li3VO4 with superior nanofibrous morphology is still successfully obtained through adjusting different heat treatment processes and different vanadium sources. The prepared Li3VO4@C nanofibers exhibit a unique structure in which nanosized Li3VO4 particles are uniformly embedded in amorphous carbon matrix. Compared with LiBVO4/C powder, Li3VO4@C nanofibers display enhanced reversible capacity of 451 mAhg^-1 at 40mAg^-1 with an increased initial coulombic efficiency of 82.3%, and the capacity can remain at 394 mAh g ^-1 after 100 cycles. This superior electrochemical performance can be attributed to its unique structure which ensures a high reactivity by nanosized Li3VO4, more stable electrode/electrolyte interface by carbon encapsulation, improved electronic conductivity and buffered volume changes by flexible carbon matrix. The electrospinning technology provides an effective method to obtain high performance Li3VO4 as a promising anode material for lithium-ion batteries.
