Highly c-axis-oriented GaN films were deposited on Ti coated glass substrates using low temperature electron cyclotron resonance plasma enhanced metal organic chemical vapor deposition system(ECR-PEMOCVD)with trimethy...Highly c-axis-oriented GaN films were deposited on Ti coated glass substrates using low temperature electron cyclotron resonance plasma enhanced metal organic chemical vapor deposition system(ECR-PEMOCVD)with trimethyl gallium(TMGa)as gallium source.The influence of TMGa flux on the properties of GaN films were systematically investigated by reflection high energy electron diffraction(RHEED),X-ray diffraction analysis(XRD),atomic force microscopy(AFM)and Raman scattering.The GaN film with small surface roughness and high c-axis preferred orientation was successfully achieved at the optimized TMGa flux of 1.0 sccm.The ohmic contact characteristic between GaN and Ti layer was clearly demonstrated by the near-linear current-voltage(I-V)curve.The GaN/Ti/glass structure has great potential to dramatically improve the scalability and reduce the cost of solid-state lighting light emitting diodes.展开更多
The problem of robust stabilization of a system family is studied here. A sufficient condition for the existence of a robust controller is presented under the assumption that there are perturbations both in the numera...The problem of robust stabilization of a system family is studied here. A sufficient condition for the existence of a robust controller is presented under the assumption that there are perturbations both in the numerator and in the denominator of the nominal system. This condition can be given by an inequality that is satisfied by the coefficient vectors of the perturbed polynomials. Based on this, the robust controller family stabilizing the system family can be obtained. Therefore, the condition has the advantages of easy computing and further satisfying other required properties.展开更多
This paper is concerned with the problem of D-stability testing for the interval matrix family. First, a nonlinearly or affine multilinearly parametrized interval polynomial family is considered. If the mapping from t...This paper is concerned with the problem of D-stability testing for the interval matrix family. First, a nonlinearly or affine multilinearly parametrized interval polynomial family is considered. If the mapping from the parameter space to the coefficient space can be expressed as an affine linear mapping of at least two variables, then it is shown that the D-stability of the family is equivalent to that of its low dimensional boundaries. In light of this result, it is proved that to determine the D-stability of an interval matrix family,it suffices to check its n!2n(n-1) n-dimensional exposed faces. Finally the results obtained are extended to the case where the rows or the columns of the matrix family are perturbed independently in different polytopes, and a result analogous to that in the interval case is obtained.展开更多
基金supported by the Opening Project of Key Laboratory of Inorganic Coating Materials,Chinese Academy of Sciences(KLICM2012-01)the Fundamental Research Funds for the Central Universities(DUT13LK02,DUT13JN08)
文摘Highly c-axis-oriented GaN films were deposited on Ti coated glass substrates using low temperature electron cyclotron resonance plasma enhanced metal organic chemical vapor deposition system(ECR-PEMOCVD)with trimethyl gallium(TMGa)as gallium source.The influence of TMGa flux on the properties of GaN films were systematically investigated by reflection high energy electron diffraction(RHEED),X-ray diffraction analysis(XRD),atomic force microscopy(AFM)and Raman scattering.The GaN film with small surface roughness and high c-axis preferred orientation was successfully achieved at the optimized TMGa flux of 1.0 sccm.The ohmic contact characteristic between GaN and Ti layer was clearly demonstrated by the near-linear current-voltage(I-V)curve.The GaN/Ti/glass structure has great potential to dramatically improve the scalability and reduce the cost of solid-state lighting light emitting diodes.
文摘The problem of robust stabilization of a system family is studied here. A sufficient condition for the existence of a robust controller is presented under the assumption that there are perturbations both in the numerator and in the denominator of the nominal system. This condition can be given by an inequality that is satisfied by the coefficient vectors of the perturbed polynomials. Based on this, the robust controller family stabilizing the system family can be obtained. Therefore, the condition has the advantages of easy computing and further satisfying other required properties.
文摘This paper is concerned with the problem of D-stability testing for the interval matrix family. First, a nonlinearly or affine multilinearly parametrized interval polynomial family is considered. If the mapping from the parameter space to the coefficient space can be expressed as an affine linear mapping of at least two variables, then it is shown that the D-stability of the family is equivalent to that of its low dimensional boundaries. In light of this result, it is proved that to determine the D-stability of an interval matrix family,it suffices to check its n!2n(n-1) n-dimensional exposed faces. Finally the results obtained are extended to the case where the rows or the columns of the matrix family are perturbed independently in different polytopes, and a result analogous to that in the interval case is obtained.
