Joint inversion is one of the most effective methods for reducing non-uniqueness for geophysical inversion.The current joint inversion methods can be divided into the structural consistency constraint and petrophysica...Joint inversion is one of the most effective methods for reducing non-uniqueness for geophysical inversion.The current joint inversion methods can be divided into the structural consistency constraint and petrophysical consistency constraint methods,which are mutually independent.Currently,there is a need for joint inversion methods that can comprehensively consider the structural consistency constraints and petrophysical consistency constraints.This paper develops the structural similarity index(SSIM)as a new structural and petrophysical consistency constraint for the joint inversion of gravity and vertical gradient data.The SSIM constraint is in the form of a fraction,which may have analytical singularities.Therefore,converting the fractional form to the subtractive form can solve the problem of analytic singularity and finally form a modified structural consistency index of the joint inversion,which enhances the stability of the SSIM constraint applied to the joint inversion.Compared to the reconstructed results from the cross-gradient inversion,the proposed method presents good performance and stability.The SSIM algorithm is a new joint inversion method for petrophysical and structural constraints.It can promote the consistency of the recovered models from the distribution and the structure of the physical property values.Then,applications to synthetic data illustrate that the algorithm proposed in this paper can well process the synthetic data and acquire good reconstructed results.展开更多
Metal particles such as aluminum( Al),magnesium( Mg),boron( B) and nickel( Ni),as well as Mg/Al alloy( Mg/Al = 3/4) are currently the most widely used ingredients in modified doublebase propellants. In this ...Metal particles such as aluminum( Al),magnesium( Mg),boron( B) and nickel( Ni),as well as Mg/Al alloy( Mg/Al = 3/4) are currently the most widely used ingredients in modified doublebase propellants. In this contribution,the combustion properties of the metal species are studied by means of the high-speed photography technique and the non-contact wavelet-based measurement of flame temperature distribution. The combustion process of the Al,Mg and Mg/Al samples shows both gas phase reaction and surface oxidation,which yield volatile and nonvolatile products,corresponding to the oxide and suboxide respectively. However,the combustion of B and Ni shows only gas phase reaction,due to their high melting point as well as high enthalpy of vaporization. In addition to the experiments,a hypothetical combustion model has been proposed to clarify the combustion characteristics of metal species in modified double-base propellants.展开更多
A new method of designing a variable structure controller for uncertain singular system is proposed in this paper. By introducing integral transformation, discontinuous control law is replaced by an approximately cont...A new method of designing a variable structure controller for uncertain singular system is proposed in this paper. By introducing integral transformation, discontinuous control law is replaced by an approximately continuous one,and the switching frequency of the variable structure control is greatly reduced and the chattering which usually occurs is ordinary variable structure control system call be effectively suppressed.展开更多
A novel synthetic strategy for the construction of 4'-spironucleosides via cascade radical translocation cyclization of N-allyl-N-(2'-bromophenyl) amide moiety of 5'-carboxylic nucleosides and the N-propynyl anal...A novel synthetic strategy for the construction of 4'-spironucleosides via cascade radical translocation cyclization of N-allyl-N-(2'-bromophenyl) amide moiety of 5'-carboxylic nucleosides and the N-propynyl analogues is described. The conformationally restricted nucleosides herein synthesized are of potentially biological interests.展开更多
基金supported by the National Key Research and Development Program(Grant No.2021YFA0716100)the National Key Research and Development Program of China Project(Grant No.2018YFC0603502)+1 种基金the Henan Youth Science Fund Program(Grant No.212300410105)the provincial key R&D and promotion special project of Henan Province(Grant No.222102320279).
文摘Joint inversion is one of the most effective methods for reducing non-uniqueness for geophysical inversion.The current joint inversion methods can be divided into the structural consistency constraint and petrophysical consistency constraint methods,which are mutually independent.Currently,there is a need for joint inversion methods that can comprehensively consider the structural consistency constraints and petrophysical consistency constraints.This paper develops the structural similarity index(SSIM)as a new structural and petrophysical consistency constraint for the joint inversion of gravity and vertical gradient data.The SSIM constraint is in the form of a fraction,which may have analytical singularities.Therefore,converting the fractional form to the subtractive form can solve the problem of analytic singularity and finally form a modified structural consistency index of the joint inversion,which enhances the stability of the SSIM constraint applied to the joint inversion.Compared to the reconstructed results from the cross-gradient inversion,the proposed method presents good performance and stability.The SSIM algorithm is a new joint inversion method for petrophysical and structural constraints.It can promote the consistency of the recovered models from the distribution and the structure of the physical property values.Then,applications to synthetic data illustrate that the algorithm proposed in this paper can well process the synthetic data and acquire good reconstructed results.
基金Supported by the Science and Technology on Combustion and Explosion Laboratory Foundation(9140C350319140C35161)
文摘Metal particles such as aluminum( Al),magnesium( Mg),boron( B) and nickel( Ni),as well as Mg/Al alloy( Mg/Al = 3/4) are currently the most widely used ingredients in modified doublebase propellants. In this contribution,the combustion properties of the metal species are studied by means of the high-speed photography technique and the non-contact wavelet-based measurement of flame temperature distribution. The combustion process of the Al,Mg and Mg/Al samples shows both gas phase reaction and surface oxidation,which yield volatile and nonvolatile products,corresponding to the oxide and suboxide respectively. However,the combustion of B and Ni shows only gas phase reaction,due to their high melting point as well as high enthalpy of vaporization. In addition to the experiments,a hypothetical combustion model has been proposed to clarify the combustion characteristics of metal species in modified double-base propellants.
文摘A new method of designing a variable structure controller for uncertain singular system is proposed in this paper. By introducing integral transformation, discontinuous control law is replaced by an approximately continuous one,and the switching frequency of the variable structure control is greatly reduced and the chattering which usually occurs is ordinary variable structure control system call be effectively suppressed.
基金the National Natural Science Foundation of China(No.20572034)
文摘A novel synthetic strategy for the construction of 4'-spironucleosides via cascade radical translocation cyclization of N-allyl-N-(2'-bromophenyl) amide moiety of 5'-carboxylic nucleosides and the N-propynyl analogues is described. The conformationally restricted nucleosides herein synthesized are of potentially biological interests.