In this study, we investigate the optimal location of access points （APs） to connect end nodes with a service provider through power-line communication in smartgrid communication networks. APs are the gateways of po...In this study, we investigate the optimal location of access points （APs） to connect end nodes with a service provider through power-line communication in smartgrid communication networks. APs are the gateways of power-distribution communication networks, connecting users to control centers. Hence, they are vital for the reliable, safe, and economical operation of a power system. This paper proposes a planning method for AP allocation that takes into consideration economics, reliability, network delay, and （n-l） resilience. First, an optimization model for the AP location is established, which minimizes the cost of installing APs, while satisfying the reliability, network delay, and （n-1） resilience constraints. Then, an improved genetic algorithm is proposed to solve the optimization problem. The simulation results indicate that the proposed planning method can deal with diverse network conditions satisfactorily. Furthermore, it can be applied effectively with high flexibility and scalability.展开更多
Nickel metal hydride battery in bipolar design offers some advantages for its application as a power storage system for electric and hybrid vehicles. This paper deals with the structure design and electrochemical stud...Nickel metal hydride battery in bipolar design offers some advantages for its application as a power storage system for electric and hybrid vehicles. This paper deals with the structure design and electrochemical studies of bipolar Ni/MH batteries for hybrid vehicles. An improvement is applied in bipolar battery design, and such bipolar Ni/MH batteries with 5 sub-cells have been assembled and investigated. Testing results show that bipolar batteries with improved structure have better compression tolerance and cycle performance than conventional ones. In addition, the improved bipolar batteries display excellent large current discharge ability and high power density. As simulating working conditions for hybrid vehicles, the batteries show good stability during pulse cycles, which verifies the possibility of being used as a power storage device on hybrid vehicles.展开更多
The device performance of CdS/CdTe solar cells largely depends on not only the back ohmic contact, but also the conformality of Cd S window layer coating. In order to reduce the light absorption loss in Cd S, the Cd S...The device performance of CdS/CdTe solar cells largely depends on not only the back ohmic contact, but also the conformality of Cd S window layer coating. In order to reduce the light absorption loss in Cd S, the Cd S thickness is usually less than 100 nm. However, pinholes in Cd S and non-conformal coverage of Cd S on transparent conducting oxide layer will cause shunting thus leading to device performance degradation and failure. In this paper, low-temperature and low-cost fabrication methods, i.e., chemical bath deposition and electrochemical deposition, were used to deposit Cd S and Cd Te, respectively. It was found that the yield of device was around 20 % due to shunting. In order to alleviate this problem, a compact layer of TiO2 was inserted between the fluorine-doped tin oxide and Cd S as a buffer layer. The thickness effect of TiO2 was studied and showed that devices with thin(20 nm thickness) TiO2 performed better than the counterparts with thick layers. It was discovered that device yield improved to 80 % and stability in air substantially improved with TiO2 layer.展开更多
Small-sized axial fans are used as air cooler for electric equipments.But there is a strong demand for higher power of fans according to the increase of quantity of heat from electric devices.Therefore,higher rotation...Small-sized axial fans are used as air cooler for electric equipments.But there is a strong demand for higher power of fans according to the increase of quantity of heat from electric devices.Therefore,higher rotational speed design is conducted,although,it causes the deterioration of efficiency and the increase of noise.Then,the adoption of contra-rotating rotors for the small-sized axial fan is proposed for the improvement of performance.In the case of contra-rotating rotors,it is necessary to design the rotor considering the unsteady flow condition of each front and rear rotor.In the present paper,the fan performance of the contra-rotating small-sized axial fan with 100mm diameter at a designed and a partial flow rates is shown,and the unsteady flow conditions at the inlet and the outlet of each front and rear rotor are clarified with unsteady numerical results.Furthermore,the relation between the performance and the unsteady flow condition of the contra-rotating small-sized axial fan is discussed and the methods to improve the performance are considered.展开更多
基金supported by the National High Technology Research and Development Program of China(2012AA050801)
文摘In this study, we investigate the optimal location of access points （APs） to connect end nodes with a service provider through power-line communication in smartgrid communication networks. APs are the gateways of power-distribution communication networks, connecting users to control centers. Hence, they are vital for the reliable, safe, and economical operation of a power system. This paper proposes a planning method for AP allocation that takes into consideration economics, reliability, network delay, and （n-l） resilience. First, an optimization model for the AP location is established, which minimizes the cost of installing APs, while satisfying the reliability, network delay, and （n-1） resilience constraints. Then, an improved genetic algorithm is proposed to solve the optimization problem. The simulation results indicate that the proposed planning method can deal with diverse network conditions satisfactorily. Furthermore, it can be applied effectively with high flexibility and scalability.
文摘Nickel metal hydride battery in bipolar design offers some advantages for its application as a power storage system for electric and hybrid vehicles. This paper deals with the structure design and electrochemical studies of bipolar Ni/MH batteries for hybrid vehicles. An improvement is applied in bipolar battery design, and such bipolar Ni/MH batteries with 5 sub-cells have been assembled and investigated. Testing results show that bipolar batteries with improved structure have better compression tolerance and cycle performance than conventional ones. In addition, the improved bipolar batteries display excellent large current discharge ability and high power density. As simulating working conditions for hybrid vehicles, the batteries show good stability during pulse cycles, which verifies the possibility of being used as a power storage device on hybrid vehicles.
基金supported by Hong Kong Innovation Technology Commission project(ITS/117/13)Hong Kong Research Grants Council project(612113)+1 种基金Fundamental Research Project of Shenzhen Science & Technology Foundation(JCYJ20130402164725025)the International Collaboration Project of Shenzhen Science & Technology Foundation(GJHZ20130417170946221)
文摘The device performance of CdS/CdTe solar cells largely depends on not only the back ohmic contact, but also the conformality of Cd S window layer coating. In order to reduce the light absorption loss in Cd S, the Cd S thickness is usually less than 100 nm. However, pinholes in Cd S and non-conformal coverage of Cd S on transparent conducting oxide layer will cause shunting thus leading to device performance degradation and failure. In this paper, low-temperature and low-cost fabrication methods, i.e., chemical bath deposition and electrochemical deposition, were used to deposit Cd S and Cd Te, respectively. It was found that the yield of device was around 20 % due to shunting. In order to alleviate this problem, a compact layer of TiO2 was inserted between the fluorine-doped tin oxide and Cd S as a buffer layer. The thickness effect of TiO2 was studied and showed that devices with thin(20 nm thickness) TiO2 performed better than the counterparts with thick layers. It was discovered that device yield improved to 80 % and stability in air substantially improved with TiO2 layer.
基金supported by Japan Science and Technology Agency and University of Tokushima and Komiya research aid
文摘Small-sized axial fans are used as air cooler for electric equipments.But there is a strong demand for higher power of fans according to the increase of quantity of heat from electric devices.Therefore,higher rotational speed design is conducted,although,it causes the deterioration of efficiency and the increase of noise.Then,the adoption of contra-rotating rotors for the small-sized axial fan is proposed for the improvement of performance.In the case of contra-rotating rotors,it is necessary to design the rotor considering the unsteady flow condition of each front and rear rotor.In the present paper,the fan performance of the contra-rotating small-sized axial fan with 100mm diameter at a designed and a partial flow rates is shown,and the unsteady flow conditions at the inlet and the outlet of each front and rear rotor are clarified with unsteady numerical results.Furthermore,the relation between the performance and the unsteady flow condition of the contra-rotating small-sized axial fan is discussed and the methods to improve the performance are considered.
