为了将PTC（positive temperature coefficient）电子浆料以厚膜电路的形式制备在不锈钢基片上，并把不锈钢本体作为散热器，引出电极利用PTC效应制成可控电热元件．方法：提出基于1Cr18Ni9不锈钢基片的PTC厚膜电路的组成结构，并根据IC...为了将PTC（positive temperature coefficient）电子浆料以厚膜电路的形式制备在不锈钢基片上，并把不锈钢本体作为散热器，引出电极利用PTC效应制成可控电热元件．方法：提出基于1Cr18Ni9不锈钢基片的PTC厚膜电路的组成结构，并根据ICr18Ni9的膨胀系数和电路元件的电气特性实现了厚膜电路PTC电子浆料的应用设计技术．结果显示以PTC厚膜电路材料组成的可控电热元件，其功率密度高达200W／cm^2；其电阻膜层的表面加热速度可达200—300℃／s；其使用寿命达到1万小时以上．可见与传统的电热合金材料、陶瓷基片加热器以及元件组合的加热器相比，本实现技术电路具有功率密度大、响应速度快、加热温度可控等优点。展开更多
In this context,a new boundary element algorithm based on the time-convoluted traction kernels is employed to evaluate the spatially varying earthquake ground motions of the Pacoima dam in the USA subjected to SH,SV a...In this context,a new boundary element algorithm based on the time-convoluted traction kernels is employed to evaluate the spatially varying earthquake ground motions of the Pacoima dam in the USA subjected to SH,SV and P incident waves.An accurate three-dimensional (3D) model of the dam canyon is implemented into the computer code BEMSA to investigate the seismic response of the dam.The analyses are performed in time domain with a linearly elastic constitutive model for the medium.This modeling procedure has been validated by the results reported in the existing literature.According to the results of this study,the response of the dam to earthquake waves is generally influenced by predominant frequency of the incident motion,surface topography,relative distance of observation points,and type of the incident seismic wave.For the cases considered,the incident SV wave has led to the maximum amplification of incident motions,especially at the left side of the dam.The results indicate that the proposed procedure can be employed for accurate prediction of a dam response during an earthquake.展开更多
In this paper, based on the conjugate of the complex basis function, a new complex variable moving least-squares approximation is discussed. Then using the new approximation to obtain the shape function, an improved c...In this paper, based on the conjugate of the complex basis function, a new complex variable moving least-squares approximation is discussed. Then using the new approximation to obtain the shape function, an improved complex variable element-free Galerkin（ICVEFG） method is presented for two-dimensional（2D） elastoplasticity problems. Compared with the previous complex variable moving least-squares approximation, the new approximation has greater computational precision and efficiency. Using the penalty method to apply the essential boundary conditions, and using the constrained Galerkin weak form of 2D elastoplasticity to obtain the system equations, we obtain the corresponding formulae of the ICVEFG method for 2D elastoplasticity. Three selected numerical examples are presented using the ICVEFG method to show that the ICVEFG method has the advantages such as greater precision and computational efficiency over the conventional meshless methods.展开更多
The author discusses necessary and sufficient conditions of the complete con- vergence for sums of B-valued independent but not necessarily identically distributed r.v.'s in Banach space of type p, and obtains cha...The author discusses necessary and sufficient conditions of the complete con- vergence for sums of B-valued independent but not necessarily identically distributed r.v.'s in Banach space of type p, and obtains characterization of Banach space of type p in terms of the complete convergence. A series of classical results on iid real valued r.v.'s are ex- tended. As application authors give the analogous results for randomly indexed sums.展开更多
This paper presents and proves the mixed compatible finite element variationalprinciples in dynamics of viscous barotropic fluids. When the principles are proved, itis found that the compatibility conditions of stress...This paper presents and proves the mixed compatible finite element variationalprinciples in dynamics of viscous barotropic fluids. When the principles are proved, itis found that the compatibility conditions of stress can be naturally satisfied. The gene-rallzed variational principles with mixed hybrid incompatible finite elements are alsopresented and proved, and they can reduce the computation of incompatible elements indynamics of viscous barotropic flows.展开更多
文摘为了将PTC（positive temperature coefficient）电子浆料以厚膜电路的形式制备在不锈钢基片上，并把不锈钢本体作为散热器，引出电极利用PTC效应制成可控电热元件．方法：提出基于1Cr18Ni9不锈钢基片的PTC厚膜电路的组成结构，并根据ICr18Ni9的膨胀系数和电路元件的电气特性实现了厚膜电路PTC电子浆料的应用设计技术．结果显示以PTC厚膜电路材料组成的可控电热元件，其功率密度高达200W／cm^2；其电阻膜层的表面加热速度可达200—300℃／s；其使用寿命达到1万小时以上．可见与传统的电热合金材料、陶瓷基片加热器以及元件组合的加热器相比，本实现技术电路具有功率密度大、响应速度快、加热温度可控等优点。
文摘In this context,a new boundary element algorithm based on the time-convoluted traction kernels is employed to evaluate the spatially varying earthquake ground motions of the Pacoima dam in the USA subjected to SH,SV and P incident waves.An accurate three-dimensional (3D) model of the dam canyon is implemented into the computer code BEMSA to investigate the seismic response of the dam.The analyses are performed in time domain with a linearly elastic constitutive model for the medium.This modeling procedure has been validated by the results reported in the existing literature.According to the results of this study,the response of the dam to earthquake waves is generally influenced by predominant frequency of the incident motion,surface topography,relative distance of observation points,and type of the incident seismic wave.For the cases considered,the incident SV wave has led to the maximum amplification of incident motions,especially at the left side of the dam.The results indicate that the proposed procedure can be employed for accurate prediction of a dam response during an earthquake.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11171208 and U1433104)
文摘In this paper, based on the conjugate of the complex basis function, a new complex variable moving least-squares approximation is discussed. Then using the new approximation to obtain the shape function, an improved complex variable element-free Galerkin（ICVEFG） method is presented for two-dimensional（2D） elastoplasticity problems. Compared with the previous complex variable moving least-squares approximation, the new approximation has greater computational precision and efficiency. Using the penalty method to apply the essential boundary conditions, and using the constrained Galerkin weak form of 2D elastoplasticity to obtain the system equations, we obtain the corresponding formulae of the ICVEFG method for 2D elastoplasticity. Three selected numerical examples are presented using the ICVEFG method to show that the ICVEFG method has the advantages such as greater precision and computational efficiency over the conventional meshless methods.
基金Supported by the Science Fund of Tongji University
文摘The author discusses necessary and sufficient conditions of the complete con- vergence for sums of B-valued independent but not necessarily identically distributed r.v.'s in Banach space of type p, and obtains characterization of Banach space of type p in terms of the complete convergence. A series of classical results on iid real valued r.v.'s are ex- tended. As application authors give the analogous results for randomly indexed sums.
文摘This paper presents and proves the mixed compatible finite element variationalprinciples in dynamics of viscous barotropic fluids. When the principles are proved, itis found that the compatibility conditions of stress can be naturally satisfied. The gene-rallzed variational principles with mixed hybrid incompatible finite elements are alsopresented and proved, and they can reduce the computation of incompatible elements indynamics of viscous barotropic flows.
