Self-collimation characteristics of the two-dimensional square-lattice photonic crystal （PC） consisting of metal rods immersed in silicon are studied by the finite-difference time-domain method. The Drude dispersion...Self-collimation characteristics of the two-dimensional square-lattice photonic crystal （PC） consisting of metal rods immersed in silicon are studied by the finite-difference time-domain method. The Drude dispersion model is adopted to describe the metal rod, and the self-collimation behaviours of the near-infrared light through the PC are studied. The frequency region and the tolerance of incident angle for the self-collimation behaviour can be controlled by changing the shape of the metal rods.展开更多
Photonic crystals （PCs） are increasingly attracting attention due to their ability to control light propagation.In this paper,the dispersion properties of a two-dimensional （2D） square lattice PCs with plane- wave...Photonic crystals （PCs） are increasingly attracting attention due to their ability to control light propagation.In this paper,the dispersion properties of a two-dimensional （2D） square lattice PCs with plane- wave expansion （PWE） method are presented,the equi-frequency contours and the band structure are analyzed,and the alignment transmission characteristics are simulated by using the finite difference time domain （FDTD） method.In addition,for the wavelength of 1.55 m,a kind of application structure with the lattice constant a=405 nm and the radius of air holes R=135 nm which can restrict the transmission of beams in photonic crystal without defect is proposed and simulated.The structure which can collimate the output beam and compress its divergence angle is easy to design.It has wide application prospects in optical communication and three-dimensional （3D） imaging lidar systems.展开更多
This paper describes the self—adjustment of some tuning-knobs of the generalized predictive controller(GPC).A three feedforward neural network was utilized to on line learn two key tuning-knobs of GPC,and BP algorith...This paper describes the self—adjustment of some tuning-knobs of the generalized predictive controller(GPC).A three feedforward neural network was utilized to on line learn two key tuning-knobs of GPC,and BP algorithm was used for the training of the linking-weights of the neural network.Hence it gets rid of the difficulty of choosing these tuning-knobs manually and provides easier condition for the wide applications of GPC on industrial plants.Simulation results illustrated the effectiveness of the method.展开更多
The relation between structures and properties of polyurethane are investigated by modern physical and chemical methods.The results obtained are as follows:the effects of the content of self-crosslinking agent on the ...The relation between structures and properties of polyurethane are investigated by modern physical and chemical methods.The results obtained are as follows:the effects of the content of self-crosslinking agent on the properties of polyurethane,i.e.,dispersion stability,dynamical viscoelasticity and mechanical properties are discussed.It is found that the optimum molar ratio of epichlorohydrin and diethylenetriamine is 1:2.A mois-展开更多
The Belt and Road Initiative contains the aspiration of Chinese nation to pursue ideological freedom and desire of strengthening international exchanges and cooperation. This paper takes the Belt and Road Initiative f...The Belt and Road Initiative contains the aspiration of Chinese nation to pursue ideological freedom and desire of strengthening international exchanges and cooperation. This paper takes the Belt and Road Initiative for example,emphasizing the interpretation of the inheritance and development of Chinese culture so as to study the importance of Culture Self-Consciousness in Chinese Philosophy,in the context of English globalization. That is to say,this paper stresses the spirits and the stand of nation 's demonstration on pursuing peace,cooperation and sustainable development in the civilization continuity from traditional China to the contemporary China,with practical philosophic view.展开更多
A compact terahertz （THz） wave collimator is proposed, which works under the frequency from 2.4 THz to 2.7 THz with a photonic crystal （PC） slab based on the self-collimation effect. The plane wave expansion （PWE...A compact terahertz （THz） wave collimator is proposed, which works under the frequency from 2.4 THz to 2.7 THz with a photonic crystal （PC） slab based on the self-collimation effect. The plane wave expansion （PWE） method is used to calculate the dispersion surfaces and the equal-frequency contours （EFCs） and optimize the structure. The propagation of the THz waves in the structure is simulated and the normalized transmission is calculated by using the finite-difference time-domain （FDTD） method with perfectly matched layer （PML） absorbing boundary conditions. Numerical simulations show that the designed collimator has a good collimation property and a high transmittance.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10904176,11004169,and 11047127)the Doctoral Foundation of Shandong Province,China (Grant No. BS2009CL028)+1 种基金the "985 Project",China (Grant No. 98507-012009)the "211 Project" of the Ministry of Education of China
文摘Self-collimation characteristics of the two-dimensional square-lattice photonic crystal （PC） consisting of metal rods immersed in silicon are studied by the finite-difference time-domain method. The Drude dispersion model is adopted to describe the metal rod, and the self-collimation behaviours of the near-infrared light through the PC are studied. The frequency region and the tolerance of incident angle for the self-collimation behaviour can be controlled by changing the shape of the metal rods.
基金supported by the Pre-research Foundation under Grant No. G020104PJ09DZ0246
文摘Photonic crystals （PCs） are increasingly attracting attention due to their ability to control light propagation.In this paper,the dispersion properties of a two-dimensional （2D） square lattice PCs with plane- wave expansion （PWE） method are presented,the equi-frequency contours and the band structure are analyzed,and the alignment transmission characteristics are simulated by using the finite difference time domain （FDTD） method.In addition,for the wavelength of 1.55 m,a kind of application structure with the lattice constant a=405 nm and the radius of air holes R=135 nm which can restrict the transmission of beams in photonic crystal without defect is proposed and simulated.The structure which can collimate the output beam and compress its divergence angle is easy to design.It has wide application prospects in optical communication and three-dimensional （3D） imaging lidar systems.
基金Supported by the National 863 CIMS Project Foundation(863-511-010)Tianjin Natural Science Foundation(983602011)Backbone Young Teacher Project Foundation of Ministry of Education
文摘This paper describes the self—adjustment of some tuning-knobs of the generalized predictive controller(GPC).A three feedforward neural network was utilized to on line learn two key tuning-knobs of GPC,and BP algorithm was used for the training of the linking-weights of the neural network.Hence it gets rid of the difficulty of choosing these tuning-knobs manually and provides easier condition for the wide applications of GPC on industrial plants.Simulation results illustrated the effectiveness of the method.
文摘The relation between structures and properties of polyurethane are investigated by modern physical and chemical methods.The results obtained are as follows:the effects of the content of self-crosslinking agent on the properties of polyurethane,i.e.,dispersion stability,dynamical viscoelasticity and mechanical properties are discussed.It is found that the optimum molar ratio of epichlorohydrin and diethylenetriamine is 1:2.A mois-
文摘The Belt and Road Initiative contains the aspiration of Chinese nation to pursue ideological freedom and desire of strengthening international exchanges and cooperation. This paper takes the Belt and Road Initiative for example,emphasizing the interpretation of the inheritance and development of Chinese culture so as to study the importance of Culture Self-Consciousness in Chinese Philosophy,in the context of English globalization. That is to say,this paper stresses the spirits and the stand of nation 's demonstration on pursuing peace,cooperation and sustainable development in the civilization continuity from traditional China to the contemporary China,with practical philosophic view.
基金Supported by the Research Projects of Science and Technology of Fujian Education Office of China(JA08178)the Research Projects of Science and Technology of Fujian Education Office of China(JA08183)
基金supported by the National Natural Science Foundation of China under Grant No.60588502
文摘A compact terahertz （THz） wave collimator is proposed, which works under the frequency from 2.4 THz to 2.7 THz with a photonic crystal （PC） slab based on the self-collimation effect. The plane wave expansion （PWE） method is used to calculate the dispersion surfaces and the equal-frequency contours （EFCs） and optimize the structure. The propagation of the THz waves in the structure is simulated and the normalized transmission is calculated by using the finite-difference time-domain （FDTD） method with perfectly matched layer （PML） absorbing boundary conditions. Numerical simulations show that the designed collimator has a good collimation property and a high transmittance.
基金The Natural Science Foundation of Fujian Province of China(No.2011J01017)the Research Project of Science and Technology of Fujian Education Office of China(No.JB11149)the Nursery Project of Science and Technology of Minjiang University(No.YKY1103)
