The Experts below are selected from a list of 177 Experts worldwide ranked by ideXlab platform
Lansun Chen - One of the best experts on this subject based on the ideXlab platform.
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Qualitative analysis of a variable yield turbidostat model with impulsive state feedback control
Journal of Applied Mathematics and Computing, 2009Co-Authors: Hongjian Guo, Lansun ChenAbstract:A turbidostat is an apparatus with feedback control system used to continuously culturing microorganisms. The dilution rate of the turbidostat can be regulated by the control system when the concentration of microorganism, detected by Photoelectricity system or other devices, reaches a preset value. Based on the design ideas of the turbidostat, a differential equation with impulsive state feedback control is proposed for a kind of turbidostat system in this paper. By the existence criteria of periodic solution of a general planar impulsive autonomous system, the conditions for the existence of periodic solution of order one are obtained according to the preset value and the types of the positive equilibrium of the corresponding system without impulsive control. Furthermore, it is pointed out that the system either tends to a stable state or has a periodic solution. Finally, the theoretical results are verified by numerical simulations.
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Periodic solution of a turbidostat system with impulsive state feedback control
Journal of Mathematical Chemistry, 2008Co-Authors: Hongjian Guo, Lansun ChenAbstract:A turbidostat is an apparatus used to continuously culturing microorganisms. The concentration of the microorganism in the turbidostat can be controlled by the Photoelectricity system or other devices. When the concentration of the microorganism is lower than a critical level, the dilution rate keeps constant. Once the concentration reaches the critical level, the dilution rate can be increased by the control of the Photoelectricity system. Based on the design ideas of the turbidostat, a differential equation with impulsive state feedback control, which has no explicit solutions, is proposed for the turbidostat system. By the existence criteria of periodic solution of a general planar impulsive autonomous system, the conditions for the existence of an order one periodic solution of the system are obtained. Furthermore, it is pointed out that the system either tends to a stable state or has a periodic solution. Finally, some discussions and numerical simulations are given.
Hongjian Guo - One of the best experts on this subject based on the ideXlab platform.
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Qualitative analysis of a variable yield turbidostat model with impulsive state feedback control
Journal of Applied Mathematics and Computing, 2009Co-Authors: Hongjian Guo, Lansun ChenAbstract:A turbidostat is an apparatus with feedback control system used to continuously culturing microorganisms. The dilution rate of the turbidostat can be regulated by the control system when the concentration of microorganism, detected by Photoelectricity system or other devices, reaches a preset value. Based on the design ideas of the turbidostat, a differential equation with impulsive state feedback control is proposed for a kind of turbidostat system in this paper. By the existence criteria of periodic solution of a general planar impulsive autonomous system, the conditions for the existence of periodic solution of order one are obtained according to the preset value and the types of the positive equilibrium of the corresponding system without impulsive control. Furthermore, it is pointed out that the system either tends to a stable state or has a periodic solution. Finally, the theoretical results are verified by numerical simulations.
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Periodic solution of a turbidostat system with impulsive state feedback control
Journal of Mathematical Chemistry, 2008Co-Authors: Hongjian Guo, Lansun ChenAbstract:A turbidostat is an apparatus used to continuously culturing microorganisms. The concentration of the microorganism in the turbidostat can be controlled by the Photoelectricity system or other devices. When the concentration of the microorganism is lower than a critical level, the dilution rate keeps constant. Once the concentration reaches the critical level, the dilution rate can be increased by the control of the Photoelectricity system. Based on the design ideas of the turbidostat, a differential equation with impulsive state feedback control, which has no explicit solutions, is proposed for the turbidostat system. By the existence criteria of periodic solution of a general planar impulsive autonomous system, the conditions for the existence of an order one periodic solution of the system are obtained. Furthermore, it is pointed out that the system either tends to a stable state or has a periodic solution. Finally, some discussions and numerical simulations are given.
Yiding Wang - One of the best experts on this subject based on the ideXlab platform.
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effect of sn substitution on the structure morphology and Photoelectricity properties of high c axis oriented cufe1 xsnxo2 thin film
Journal of Alloys and Compounds, 2015Co-Authors: Yahui Chuai, Hongzhi Shen, Chuantao Zheng, Yiding WangAbstract:Abstract Epitaxial thin films of CuFe 1 − x Sn x O 2 ( x = 0.00, 0.01, 0.03, 0.05, 0.07), a transparent oxide semiconductor with delafossite structure, were grow on Al 2 O 3 (0 0 0 1) substrate by sol–gel method, The X-ray diffraction patterns revealed that the CuFeO 2 film annealed at 500 °C in air was mainly composed of amorphous phase, and after post-annealed at 900 °C in N 2 , single phase CuFe 1 − x Sn x O 2 films with high c -axis oriented were obtained. The Raman spectrum confirmed the delafossite structure of the films. The binding energy of Cu-2p 3/2 , Fe-2p 3/2 and Sn-3d 5/2 were 932 eV, 711.3 eV and 486.2 eV in CuFe 1 − x Sn x O 2 films. The chemical composition of the films was close to its stoichiometry, which was determined by X-ray photoelectron spectroscopy. The films show high transmittance around 45–78% in the visible band and 78–95% in the near infrared spectral region, while the energy gaps for direct allowed transition were estimated as 3.5 ± 0.02 eV. The p-type characteristics of CuFe 1 − x Sn x O 2 thin films were determined by positive Hall coefficients. The resistivity of the film was 36.83 Ω cm for CuFeO 2 film at room temperature, significantly decreased to 1.043 Ω cm after substituting Sn 2+ for Fe 3+ . The resistivity showed a decrease at the beginning and increased with the growing of Sn ion doping ratio. These results demonstrate that the high c -axis oriented CuFe 1 − x Sn x O 2 films can be the very promising p-type transparent conductive thin films.
Yahui Chuai - One of the best experts on this subject based on the ideXlab platform.
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effect of sn substitution on the structure morphology and Photoelectricity properties of high c axis oriented cufe1 xsnxo2 thin film
Journal of Alloys and Compounds, 2015Co-Authors: Yahui Chuai, Hongzhi Shen, Chuantao Zheng, Yiding WangAbstract:Abstract Epitaxial thin films of CuFe 1 − x Sn x O 2 ( x = 0.00, 0.01, 0.03, 0.05, 0.07), a transparent oxide semiconductor with delafossite structure, were grow on Al 2 O 3 (0 0 0 1) substrate by sol–gel method, The X-ray diffraction patterns revealed that the CuFeO 2 film annealed at 500 °C in air was mainly composed of amorphous phase, and after post-annealed at 900 °C in N 2 , single phase CuFe 1 − x Sn x O 2 films with high c -axis oriented were obtained. The Raman spectrum confirmed the delafossite structure of the films. The binding energy of Cu-2p 3/2 , Fe-2p 3/2 and Sn-3d 5/2 were 932 eV, 711.3 eV and 486.2 eV in CuFe 1 − x Sn x O 2 films. The chemical composition of the films was close to its stoichiometry, which was determined by X-ray photoelectron spectroscopy. The films show high transmittance around 45–78% in the visible band and 78–95% in the near infrared spectral region, while the energy gaps for direct allowed transition were estimated as 3.5 ± 0.02 eV. The p-type characteristics of CuFe 1 − x Sn x O 2 thin films were determined by positive Hall coefficients. The resistivity of the film was 36.83 Ω cm for CuFeO 2 film at room temperature, significantly decreased to 1.043 Ω cm after substituting Sn 2+ for Fe 3+ . The resistivity showed a decrease at the beginning and increased with the growing of Sn ion doping ratio. These results demonstrate that the high c -axis oriented CuFe 1 − x Sn x O 2 films can be the very promising p-type transparent conductive thin films.
Xianzhong Cheng - One of the best experts on this subject based on the ideXlab platform.
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removal of phosphate from landscape water using an electrocoagulation process powered directly by photovoltaic solar modules
Solar Energy Materials and Solar Cells, 2013Co-Authors: Shunxi Zhang, Jian Zhang, Wenqing Wang, Furong Li, Xianzhong ChengAbstract:Abstract In this paper, removal of phosphate from landscape water using an electrocoagulation process with aluminum electrodes powered directly by photovoltaic solar modules was investigated. The results showed that total phosphate (TP) residual concentration in landscape water decreases with an increasing electrolysis time. A first order kinetics about TP removal is concluded. An optimum electrode gap of 25 mm is determined. Conductivity of landscape water was adjusted by adding NaCl, and an optimum initial conductivity range of 765–1135 μS/cm can be obtained. In an overcast day, a higher TP removal efficiency can be obtained by extending time. TP removal efficiency increases with an increasing number of serial photovoltaic modules during early reaction. The optimal condition, order and significance of the factors on TP removal were determined by an orthogonal test with four factors and three levels, and the predictive value for TP removal efficiency is (97.77±2.13)%. Photoelectricity conversion efficiency for an overcast day is the highest and 12.2%. However, energy for removing a unit mass of TP and energy for removing TP per volume unit are all the lowest, and values are 15.75 kWh/kg and 0.71 kWh/m 3 , respectively. The process used for removal of phosphate from landscape water is feasible.