In order to solve the problem the existing vertical handoff algorithms of vehicle heterogeneous wireless network do not consider the diversification of network's status, an optimized vertical handoff algorithm bas...In order to solve the problem the existing vertical handoff algorithms of vehicle heterogeneous wireless network do not consider the diversification of network's status, an optimized vertical handoff algorithm based on markov process is proposed and discussed in this paper. This algorithm takes into account that the status transformation of available network will affect the quality of service(Qo S) of vehicle terminal's communication service. Firstly, Markov process is used to predict the transformation of wireless network's status after the decision via transition probability. Then the weights of evaluating parameters will be determined by fuzzy logic method. Finally, by comparing the total incomes of each wireless network, including handoff decision incomes, handoff execution incomes and communication service incomes after handoff, the optimal network to handoff will be selected. Simulation results show that: the algorithm proposed, compared to the existing algorithm, is able to receive a higher level of load balancing and effectively improves the average blocking rate, packet loss rate and ping-pang effect.展开更多
The influence of surface/interface roughness on the magnetic properties of Fe/Ni multilayers is investigated.Two methods are employed to tune the film roughness:one varies the substrate temperature,and the other pre-d...The influence of surface/interface roughness on the magnetic properties of Fe/Ni multilayers is investigated.Two methods are employed to tune the film roughness:one varies the substrate temperature,and the other pre-deposits a Ag underlayer on the MgO substrate.For films with higher roughness,a marked rise in coercivity is observed.Three factors are discussed to be mainly responsible for the coercivity rise,involving the formation of pinholes,the reduction of exchange coupling between Fe and Ni layers,and Fe-Ni alloying at interfaces.展开更多
The influence of the electropolishing and anodization voltage on surface morphology has been carefully studied for fabrication of ordered anodic aluminum oxide （AAO） templates. In accordance with that in the anodiza...The influence of the electropolishing and anodization voltage on surface morphology has been carefully studied for fabrication of ordered anodic aluminum oxide （AAO） templates. In accordance with that in the anodization experiment, the size of small patterns on the foil surface formed from the electropolishing treatment increases with voltage. Using a combined method of small-voltage eleetropolishing and anodization, we have fabricated well ordered templates with much smaller interpore distances compared with that under normal-voltage fabrication conditions. The Ni nanowire arrays with two small diameters are eleetrodeposited through the above templates, exhibiting different magnetic properties. This also helps us to clarify the inner structure of this kind of templates.展开更多
基金supported in part by the National Natural Science Foundation of China under grant No. 61271259, No. 61301123, No. 61471076Scientific and Technological Research Program of Chongqing Municipal Education Commission of Chongqing of China under Grant No.KJ130536
文摘In order to solve the problem the existing vertical handoff algorithms of vehicle heterogeneous wireless network do not consider the diversification of network's status, an optimized vertical handoff algorithm based on markov process is proposed and discussed in this paper. This algorithm takes into account that the status transformation of available network will affect the quality of service(Qo S) of vehicle terminal's communication service. Firstly, Markov process is used to predict the transformation of wireless network's status after the decision via transition probability. Then the weights of evaluating parameters will be determined by fuzzy logic method. Finally, by comparing the total incomes of each wireless network, including handoff decision incomes, handoff execution incomes and communication service incomes after handoff, the optimal network to handoff will be selected. Simulation results show that: the algorithm proposed, compared to the existing algorithm, is able to receive a higher level of load balancing and effectively improves the average blocking rate, packet loss rate and ping-pang effect.
基金Supported by the National Natural Science Foundation of China under Grant Nos 51071046,61078030,11074046,11174056,11274113the National Basic Research Program of China(2009CB929201)the Characterization Facility,University of Minnesota,a member of the NSF-funded Materials Research Facilities Network(www.mrfn.org)via the NSF MRSEC program under award number DMR-0819885.
文摘The influence of surface/interface roughness on the magnetic properties of Fe/Ni multilayers is investigated.Two methods are employed to tune the film roughness:one varies the substrate temperature,and the other pre-deposits a Ag underlayer on the MgO substrate.For films with higher roughness,a marked rise in coercivity is observed.Three factors are discussed to be mainly responsible for the coercivity rise,involving the formation of pinholes,the reduction of exchange coupling between Fe and Ni layers,and Fe-Ni alloying at interfaces.
基金Supported by the National Natural Science Foundation of China under Grant Nos 50771032, 50771033, 10604016 and 60678008, and the National Basic Research Program of China under Grant No 2009CB929201.
文摘The influence of the electropolishing and anodization voltage on surface morphology has been carefully studied for fabrication of ordered anodic aluminum oxide （AAO） templates. In accordance with that in the anodization experiment, the size of small patterns on the foil surface formed from the electropolishing treatment increases with voltage. Using a combined method of small-voltage eleetropolishing and anodization, we have fabricated well ordered templates with much smaller interpore distances compared with that under normal-voltage fabrication conditions. The Ni nanowire arrays with two small diameters are eleetrodeposited through the above templates, exhibiting different magnetic properties. This also helps us to clarify the inner structure of this kind of templates.
