The Ni-base single crystal superalloy was bonded by the transient liquid phase (TLP) bonding, using a Ni-base flexible metal cloth as an insert alloy. TLP bonding of superalloy was carried out at 1473-1523 K for 0.5-2...The Ni-base single crystal superalloy was bonded by the transient liquid phase (TLP) bonding, using a Ni-base flexible metal cloth as an insert alloy. TLP bonding of superalloy was carried out at 1473-1523 K for 0.5-24 h in vacuum. The [001] orientation of each test specimen was aligned perpendicular to the joint interface. The bonded region was observed by optical microscopy, and the microstructural and compositional analyses across the bonded interlayer were performed by using a scanning electron microscopy (SEM). The electron back scattering diffraction (EBSD) method was applied to determine the crystallographic orientation. The results indicated that the chemical homogeneity across the bonded region can be achieved, and γ' phase both in the bonded interlayer and in the superalloy substrate is almost identical, while the bonded interlayer had almost matched the crystallographic orientation of the bonded substrates.展开更多
The nickel hydroxide prepared by micro-emulsion method was doped by coprecipitated Zn. The effect of the amount of zinc-doped on the properties of Ni(OH)2 such as the reversibility of the electrode reaction, the charg...The nickel hydroxide prepared by micro-emulsion method was doped by coprecipitated Zn. The effect of the amount of zinc-doped on the properties of Ni(OH)2 such as the reversibility of the electrode reaction, the charge efficiency and active material utilization ratio of nickel electrode, and discharge specific capacity was studied by cyclic voltammetry and constant current charge-discharge tests. The results indicate that the specific discharge capacity of nickel hydroxide obtained by micro-emulsion method is much less than its theoretical value because the transfer of electrons and the diffusion of protons H+ are hindered owing to its crystal grain size in a nanometer range and thus possessing higher crystal interface resistance. The crystal cells are swelled and the crystal defects increased in prepared material due to part of Ni2+ substituted by Zn2+ when zinc and nickel hydroxide are coprecipitated. Hence, the electrons and protons H+ in the electrode reaction are transferred easily, the electrochemical behavior of nickel electrode is improved and discharge specific capacity is promoted. However, the performance of Ni(OH)2 is gradually enhanced with the addition of zinc-doped at first, while slowly decreased after the content of zinc is added to a certain value. The best electrode reaction reversibility, the highest electrode charge efficiency, the highest active material utilization ratio and the largest specific capacity on discharge are available when the mass fraction of Zn doped in nickel hydroxide by coprecipitation reaches 2.5 %.展开更多
A neural network model with a special structure, which is divided into linearand nonlinear parts, was proposed for identification of a nonlinear system. In this model, thenonlinear part of the object is treated as a m...A neural network model with a special structure, which is divided into linearand nonlinear parts, was proposed for identification of a nonlinear system. In this model, thenonlinear part of the object is treated as a measured disturbance, and is compensated by a feedforward method; an adaptive pole placement algorithm is used to control the linear part of theobject. The simulation results show that the identification efficiency and accuracy are improvedwhen the new controller is applied to sintering finish point control.展开更多
An approach of adaptive predictive control with a new structure and a fast algorithm of neural network (NN) is proposed. NN modeling and optimal predictive control are combined to achieve both accuracy and good contro...An approach of adaptive predictive control with a new structure and a fast algorithm of neural network (NN) is proposed. NN modeling and optimal predictive control are combined to achieve both accuracy and good control performance. The output of nonlinear network model is adopted as a measured disturbance that is therefore weakened in predictive feed-forward control. Simulation and practical application show the effectiveness of control by the proposed approach.展开更多
In this note we present a perturbation bound of unitary polar factors.We add the orthogonalprojectors into the bound;as a result,a uniform perturbation bound of Q-factors is obtained,and the previousbounds are improved.
文摘The Ni-base single crystal superalloy was bonded by the transient liquid phase (TLP) bonding, using a Ni-base flexible metal cloth as an insert alloy. TLP bonding of superalloy was carried out at 1473-1523 K for 0.5-24 h in vacuum. The [001] orientation of each test specimen was aligned perpendicular to the joint interface. The bonded region was observed by optical microscopy, and the microstructural and compositional analyses across the bonded interlayer were performed by using a scanning electron microscopy (SEM). The electron back scattering diffraction (EBSD) method was applied to determine the crystallographic orientation. The results indicated that the chemical homogeneity across the bonded region can be achieved, and γ' phase both in the bonded interlayer and in the superalloy substrate is almost identical, while the bonded interlayer had almost matched the crystallographic orientation of the bonded substrates.
文摘The nickel hydroxide prepared by micro-emulsion method was doped by coprecipitated Zn. The effect of the amount of zinc-doped on the properties of Ni(OH)2 such as the reversibility of the electrode reaction, the charge efficiency and active material utilization ratio of nickel electrode, and discharge specific capacity was studied by cyclic voltammetry and constant current charge-discharge tests. The results indicate that the specific discharge capacity of nickel hydroxide obtained by micro-emulsion method is much less than its theoretical value because the transfer of electrons and the diffusion of protons H+ are hindered owing to its crystal grain size in a nanometer range and thus possessing higher crystal interface resistance. The crystal cells are swelled and the crystal defects increased in prepared material due to part of Ni2+ substituted by Zn2+ when zinc and nickel hydroxide are coprecipitated. Hence, the electrons and protons H+ in the electrode reaction are transferred easily, the electrochemical behavior of nickel electrode is improved and discharge specific capacity is promoted. However, the performance of Ni(OH)2 is gradually enhanced with the addition of zinc-doped at first, while slowly decreased after the content of zinc is added to a certain value. The best electrode reaction reversibility, the highest electrode charge efficiency, the highest active material utilization ratio and the largest specific capacity on discharge are available when the mass fraction of Zn doped in nickel hydroxide by coprecipitation reaches 2.5 %.
文摘A neural network model with a special structure, which is divided into linearand nonlinear parts, was proposed for identification of a nonlinear system. In this model, thenonlinear part of the object is treated as a measured disturbance, and is compensated by a feedforward method; an adaptive pole placement algorithm is used to control the linear part of theobject. The simulation results show that the identification efficiency and accuracy are improvedwhen the new controller is applied to sintering finish point control.
基金the National Natural Science Foundation of China (No. 60075012).
文摘An approach of adaptive predictive control with a new structure and a fast algorithm of neural network (NN) is proposed. NN modeling and optimal predictive control are combined to achieve both accuracy and good control performance. The output of nonlinear network model is adopted as a measured disturbance that is therefore weakened in predictive feed-forward control. Simulation and practical application show the effectiveness of control by the proposed approach.
基金Supported in part by Guangdong Provincial Natural Science Foundation (No.31496)Nature Science Foundation of Guangdong Provincial University Teachers (No.0119)Guangdong Provincial Excellent Talent Foundation (No.Q02084)
文摘In this note we present a perturbation bound of unitary polar factors.We add the orthogonalprojectors into the bound;as a result,a uniform perturbation bound of Q-factors is obtained,and the previousbounds are improved.
