The tooth surface shape of hypoid gear is very complicated, and tooth surface accuracy of hypoid gear can be measured by using the latticed measurement and scanning measurement. Advantages and disadvantages of the two...The tooth surface shape of hypoid gear is very complicated, and tooth surface accuracy of hypoid gear can be measured by using the latticed measurement and scanning measurement. Advantages and disadvantages of the two measurement patterns are compared and application of their measurement data on hypoid gear＇s quality management is analyzed. How to use these measurement data to simulate the dynamical performance of hypoid gear is researched, and the intelligent predicton of the dynamical performance indexes of contact spot, root stress, vibration exciting forces and load distribution and hertz contact stress on the tooth surface are carried out. This research work has an important guiding sense to design and ma- chine hypoid gear with low vibration and noise.展开更多
Consider a four-dimensional system having a two-dimensional invariant surface. By analyzing the solutions of bifurcation equations, this paper studied the bifurcation phenomena of a k multiple closed orbit in the inva...Consider a four-dimensional system having a two-dimensional invariant surface. By analyzing the solutions of bifurcation equations, this paper studied the bifurcation phenomena of a k multiple closed orbit in the invariant surface. Sufficient conditions for the existence of periodic orbits generated by the k multiple closed orbit were given.展开更多
This paper discusses propagation of perturbations along traffic flow modeled by a modified second-order macroscopic model through the wavefront expansion technique. The coefficients in this expansion satisfy a sequenc...This paper discusses propagation of perturbations along traffic flow modeled by a modified second-order macroscopic model through the wavefront expansion technique. The coefficients in this expansion satisfy a sequence of transport equations that can be solved analytically. One of these analytic solutions yields information about wavefront shock. Numerical simulations based on a Padé approximation of this expansion were done at the end of this paper and results showed that propagation of perturbations at traffic flow speed conforms to the theoretical analysis results.展开更多
This paper focuses on robust control problems for supercavitating vehicles in the vertical plane. Firstly, for the mathematical model with mismatched uncertainties, the robust sliding mode function is designed based o...This paper focuses on robust control problems for supercavitating vehicles in the vertical plane. Firstly, for the mathematical model with mismatched uncertainties, the robust sliding mode function is designed based on the guaranteed cost theory, and a sufficient condition for the existence is given in terms of linear matrix inequality （LMI）. Secondly, a continuous sliding mode controller is proposed to handle the nonlinear, time - varying behavior of the vehicles. Simulation results demonstrate that the system responds rapidly and has good robust stability. Therefore, it provides theoretical references for further study on control problems of supercavitating vehicles.展开更多
Etching process of back-illuminated ZnO ultraviolet focal plane array imagers was investigated. The etching result of 128 × 128 array ,in which the area of unit ceil was 25μm × 25μm, was studied. The profi...Etching process of back-illuminated ZnO ultraviolet focal plane array imagers was investigated. The etching result of 128 × 128 array ,in which the area of unit ceil was 25μm × 25μm, was studied. The profile angle was approximately 80°. There was a linear relationship between the etching depth and the etching time. The dependence of etching rate on NH4Cl solution concentration was also studied. The photoresponsivity of the array＇s unit cells was measured. The UV-to- visible rejection ratio was around 60 ： 1.展开更多
基金National Natural Science Foundation of China（No. 50976108）
文摘The tooth surface shape of hypoid gear is very complicated, and tooth surface accuracy of hypoid gear can be measured by using the latticed measurement and scanning measurement. Advantages and disadvantages of the two measurement patterns are compared and application of their measurement data on hypoid gear＇s quality management is analyzed. How to use these measurement data to simulate the dynamical performance of hypoid gear is researched, and the intelligent predicton of the dynamical performance indexes of contact spot, root stress, vibration exciting forces and load distribution and hertz contact stress on the tooth surface are carried out. This research work has an important guiding sense to design and ma- chine hypoid gear with low vibration and noise.
文摘Consider a four-dimensional system having a two-dimensional invariant surface. By analyzing the solutions of bifurcation equations, this paper studied the bifurcation phenomena of a k multiple closed orbit in the invariant surface. Sufficient conditions for the existence of periodic orbits generated by the k multiple closed orbit were given.
文摘This paper discusses propagation of perturbations along traffic flow modeled by a modified second-order macroscopic model through the wavefront expansion technique. The coefficients in this expansion satisfy a sequence of transport equations that can be solved analytically. One of these analytic solutions yields information about wavefront shock. Numerical simulations based on a Padé approximation of this expansion were done at the end of this paper and results showed that propagation of perturbations at traffic flow speed conforms to the theoretical analysis results.
基金Supported by the National Natural Science Foundation of China（ No. 10802026） and Research Fund for the Doctoral Program of Higher Education of China （ No. 200802130003 ）.
文摘This paper focuses on robust control problems for supercavitating vehicles in the vertical plane. Firstly, for the mathematical model with mismatched uncertainties, the robust sliding mode function is designed based on the guaranteed cost theory, and a sufficient condition for the existence is given in terms of linear matrix inequality （LMI）. Secondly, a continuous sliding mode controller is proposed to handle the nonlinear, time - varying behavior of the vehicles. Simulation results demonstrate that the system responds rapidly and has good robust stability. Therefore, it provides theoretical references for further study on control problems of supercavitating vehicles.
文摘Etching process of back-illuminated ZnO ultraviolet focal plane array imagers was investigated. The etching result of 128 × 128 array ,in which the area of unit ceil was 25μm × 25μm, was studied. The profile angle was approximately 80°. There was a linear relationship between the etching depth and the etching time. The dependence of etching rate on NH4Cl solution concentration was also studied. The photoresponsivity of the array＇s unit cells was measured. The UV-to- visible rejection ratio was around 60 ： 1.
