We investigate in this article the thermal coliductivity of array Of cylinders embedded in a homogeneous matrix. Using Green's function, we confirm that the method invented by Rayleigh can be generalized to deal w...We investigate in this article the thermal coliductivity of array Of cylinders embedded in a homogeneous matrix. Using Green's function, we confirm that the method invented by Rayleigh can be generalized to deal with thermal property of these systems. A technique for calculating effective thermal conductivities of these systems is proposed. As an example, we consider a system with square symmetry, and a neat formula for effective thermal conductivity is derived. We show that the method also includes the proof of Keller theorem.展开更多
A control method of direct adaptive control based on gradient estimation is proposed in this article. The dynamic system is embedded in a linear model set. Based on the embedding property of the dynamic system, an ada...A control method of direct adaptive control based on gradient estimation is proposed in this article. The dynamic system is embedded in a linear model set. Based on the embedding property of the dynamic system, an adaptive optimal control algorithm is proposed. The robust convergence of the proposed control algorithm has been proved and the static control error with the proposed method is also analyzed. The application results of the proposed method to the industrial polypropylene process have verified its feasibility and effectiveness.展开更多
Electrical properties of C/Ni films are studied using four mosaic targets made of pure graphite and stripes of nickel with the surface areas of 1.78,3.21,3.92 and 4.64%.The conductivity data in the temperature range o...Electrical properties of C/Ni films are studied using four mosaic targets made of pure graphite and stripes of nickel with the surface areas of 1.78,3.21,3.92 and 4.64%.The conductivity data in the temperature range of400-500 K shows the extended state conduction.The conductivity data in the temperature range of 150-300 K shows the multi-phonon hopping conduction.The Berthelot-type conduction dominates in the temperature range of 50-150 K.The conductivity of the films in the temperature range about 〈 50 K is described in terms of variable-range hopping conduction.In low temperatures,the localized density of state around Fermi level（F）for the film deposition with 3.92% nickel has a maximum value of about 56.2×10^（17）cm^（-3）eV^（-1） with the minimum average hopping distance of about 3.43 × 10^（-6） cm.展开更多
Cu-doped borate glass co-doped with SnO2nanoparticles is fabricated by melt quenching.The structure and morphology of the samples are examined by X-ray diffraction and field emission scanning electron microscopy.Up-co...Cu-doped borate glass co-doped with SnO2nanoparticles is fabricated by melt quenching.The structure and morphology of the samples are examined by X-ray diffraction and field emission scanning electron microscopy.Up-conversion enhancement is observed in the photoluminescence（PL） and thermoluminescence（TL） intensities of the glass.PL emission spectra are identified in the blue and green regions,and a fourfold increase in emission intensity may be observed in the presence of embedded SnO2nanoparticles.The glow curve is recorded at 215 C,and fourfold increases in TL intensity are obtained by addition of 0.1 mol% SnO2nanoparticles to the glass.Higher TL responses of the samples are observed in the energy range of 15-100 KeV.At energy levels greater than;.1 MeV,however,flat responses are obtained.The activation energy and frequency factor of the second-order kinetic reaction are calculated by the peak shape method.展开更多
文摘We investigate in this article the thermal coliductivity of array Of cylinders embedded in a homogeneous matrix. Using Green's function, we confirm that the method invented by Rayleigh can be generalized to deal with thermal property of these systems. A technique for calculating effective thermal conductivities of these systems is proposed. As an example, we consider a system with square symmetry, and a neat formula for effective thermal conductivity is derived. We show that the method also includes the proof of Keller theorem.
基金Supported by the National Natural Science Foundation of China （60774080） and BJNOVA 2005B 15.
文摘A control method of direct adaptive control based on gradient estimation is proposed in this article. The dynamic system is embedded in a linear model set. Based on the embedding property of the dynamic system, an adaptive optimal control algorithm is proposed. The robust convergence of the proposed control algorithm has been proved and the static control error with the proposed method is also analyzed. The application results of the proposed method to the industrial polypropylene process have verified its feasibility and effectiveness.
文摘Electrical properties of C/Ni films are studied using four mosaic targets made of pure graphite and stripes of nickel with the surface areas of 1.78,3.21,3.92 and 4.64%.The conductivity data in the temperature range of400-500 K shows the extended state conduction.The conductivity data in the temperature range of 150-300 K shows the multi-phonon hopping conduction.The Berthelot-type conduction dominates in the temperature range of 50-150 K.The conductivity of the films in the temperature range about 〈 50 K is described in terms of variable-range hopping conduction.In low temperatures,the localized density of state around Fermi level（F）for the film deposition with 3.92% nickel has a maximum value of about 56.2×10^（17）cm^（-3）eV^（-1） with the minimum average hopping distance of about 3.43 × 10^（-6） cm.
基金RMC, UTM for providing research funding to complete this work
文摘Cu-doped borate glass co-doped with SnO2nanoparticles is fabricated by melt quenching.The structure and morphology of the samples are examined by X-ray diffraction and field emission scanning electron microscopy.Up-conversion enhancement is observed in the photoluminescence（PL） and thermoluminescence（TL） intensities of the glass.PL emission spectra are identified in the blue and green regions,and a fourfold increase in emission intensity may be observed in the presence of embedded SnO2nanoparticles.The glow curve is recorded at 215 C,and fourfold increases in TL intensity are obtained by addition of 0.1 mol% SnO2nanoparticles to the glass.Higher TL responses of the samples are observed in the energy range of 15-100 KeV.At energy levels greater than;.1 MeV,however,flat responses are obtained.The activation energy and frequency factor of the second-order kinetic reaction are calculated by the peak shape method.
