O731 2000021386非简谐性离子晶格在光场中的能谱:动态斯塔克效应=Energy spectrum of anharmonic ionic-crystallattice in lightfield a dynamical Stark effect[刊,中]/欧发(华南理工大学应用物理系.广东,广州(510641)),何明高,吴福...O731 2000021386非简谐性离子晶格在光场中的能谱:动态斯塔克效应=Energy spectrum of anharmonic ionic-crystallattice in lightfield a dynamical Stark effect[刊,中]/欧发(华南理工大学应用物理系.广东,广州(510641)),何明高,吴福根(广东工业大学数理系.广东,广州(510090))//光学学报.-1999,19(7).-889-895以在偶极近似与旋转波近似下导出的哈密顿算符为基础,并以单模光频支声子与单模光场构成的共振耦合系统为简化模型,取得该耦合系统相互作用能谱的比较严格的解析解,同时还发现一种起源于声子-声子耦合的真空平移效应。图2参9(严寒)展开更多
The coherent and incoherent interactions between discrete-soliton trains are numerically investigated in lightinduced two-dimensional photonic lattices. The solutions of discrete-soliton trains for diamond and square ...The coherent and incoherent interactions between discrete-soliton trains are numerically investigated in lightinduced two-dimensional photonic lattices. The solutions of discrete-soliton trains for diamond and square lattices are obtained by Petviashvili iteration method. It is found that for both the kinds of lattices, two in-phase （out- of-phase） discrete-soliton trains attract （repel） each other, and the intermediates are always accompanied with energy transfer. While the interaction forces between two incoherent discrete-soliton trains are always attractive.展开更多
To understand the effect of the doping amount of Cu^2+ on the structure and reactivity of SnO2 in NOx-SCR with NH3, a series of Sn-Cu-O binary oxide catalysts with different Sn/Cu ratios have been prepared and thoroug...To understand the effect of the doping amount of Cu^2+ on the structure and reactivity of SnO2 in NOx-SCR with NH3, a series of Sn-Cu-O binary oxide catalysts with different Sn/Cu ratios have been prepared and thoroughly characterized. Using the XRD extrapolation method, the SnO2 lattice capacity for Cu^2+ cations is determined at 0.10 g Cu O per g of SnO2, equaling a Sn/Cu molar ratio of 84/16. Therefore, in a tetragonal rutile SnO2 lattice, only a maximum of 16% of the Sn4+ cations can be replaced by Cu^2+ to form a stable solid solution structure. If the Cu content is higher, Cu O will form on the catalyst surface, which has a negative effect on the reaction performance. For samples in a pure solid solution phase, the number of surface defects increase with increasing Cu content until it reaches the lattice capacity, as confirmed by Raman spectroscopy. As a result, the amounts of both active oxygen species and acidic sites on the surface, which critically determine the reaction performance, also increase and reach the maximum level for the catalyst with a Cu content close to the lattice capacity. A distinct lattice capacity threshold effect on the structure and reactivity of Sn-Cu binary oxide catalysts has been observed. A Sn-Cu catalyst with the best reaction performance can be obtained by doping the SnO2 matrix with the lattice capacity amount of Cu^2+.展开更多
This paper describes the design of a FeWOx-based oxygen carrier for the chemical partial oxidation of methane(CLPOM).Thermodynamic screening and kinetic analyses both forecast the FeWOx-based oxygen carrier as a promi...This paper describes the design of a FeWOx-based oxygen carrier for the chemical partial oxidation of methane(CLPOM).Thermodynamic screening and kinetic analyses both forecast the FeWOx-based oxygen carrier as a promising candidate for the production of syngas.The total methane conversion and syngas yield can be dramatically increased with this catalyst compared to the case with the unmodified WO3/SiO2,thereby enabling CLPOM with 62%methane conversion,93%CO gas-phase selectivity,94%H2 selectivity,and a 2.4 H2/CO ratio.The catalyst has the advantages of high availability of lattice oxygen to oxidize carbonaceous intermediates in time,together with the formation of an Fe-W alloy to promote the surface reaction.Consequently,it demonstrates excellent catalytic performance with no catalyst deactivation at 900°C and 1 atm.The excellent structural stability plays an essential role in CLPOM.As revealed via XPS and ICP,the phase segregation has not been observed due to the strong interaction between Fe and W,which resulted in the formation of the Fe-W alloy during the reduction processes and the match between the ion oxidation rates of the Fe and W ions in the oxidation stage.The results provide fundamental information on the reaction mechanism of FeWOx/SiO2,and present it as a promising candidate for CLPOM.展开更多
Starting from a discrete spectral problem, a hierarchy of integrable lattice soliton equations is derived. It is shown that the hierarchy is completely integrable in the Liouville sense and possesses discrete bi-Hamil...Starting from a discrete spectral problem, a hierarchy of integrable lattice soliton equations is derived. It is shown that the hierarchy is completely integrable in the Liouville sense and possesses discrete bi-Hamiltonian structure. A new integrable symplectic map and finite-dimensional integrable systems are given by nonlinearization method. The binary Bargmann constraint gives rise to a Biicklund transformation for the resulting integrable lattice equations. At last, conservation laws of the hierarchy are presented.展开更多
In this paper, we extend a （2＋2）-dimensional continuous zero curvature equation to （2＋2）-dimensional discrete zero curvature equation, then a new （2＋2）-dimensional cubic Volterra lattice hierarchy is obtained...In this paper, we extend a （2＋2）-dimensional continuous zero curvature equation to （2＋2）-dimensional discrete zero curvature equation, then a new （2＋2）-dimensional cubic Volterra lattice hierarchy is obtained. Fhrthermore, the integrable coupling systems of the （2＋2）-dimensional cubic Volterra lattice hierarchy and the generalized Toda lattice soliton equations are presented by using a Lie algebraic system sl（4）.展开更多
We have fabricated a series of square-lattice hole photonic crystal (2PhC) arrays simultaneously at the un-current injection region on a special sample of GaN based light emitting diode (LED) by using focus ion beam m...We have fabricated a series of square-lattice hole photonic crystal (2PhC) arrays simultaneously at the un-current injection region on a special sample of GaN based light emitting diode (LED) by using focus ion beam milling (FIBM). The lattice constants of the 2PhC arrays vary from 230 to 1500 nm,while the 2PhC arrays have a constant area of about 9 μm×18 μm and a fixed depth of 150±10 nm which approaches but does not penetrate the active layer. Microscopic electroluminescence images and spectral measurements consistently confirm that the top emitting intensities from different 2PhCs are all enhanced compared with the unpatterned region. It is demonstrated that the output coupling of propagating guided modes is realized by the diffracted transmission of the 2PhCs. The enhancement factors of the guided modes compared with the unpatterned region are plotted as function of the lattice constant. It is found that the highest enhancements for the extraction of guided modes were obtained for the lattice constant of 230 and 460 nm of 2PhCs. The results are discussed by the two-dimensional rigorous coupled wave analysis (RCWA).展开更多
Cu12Sb4S13 tetrahedrite has received great attention as an earth-abundant and environmental-friendly thermoelectric material. This work aims to uncover the thermoelectric performance-enhancing effect and the mechanism...Cu12Sb4S13 tetrahedrite has received great attention as an earth-abundant and environmental-friendly thermoelectric material. This work aims to uncover the thermoelectric performance-enhancing effect and the mechanism of nickel doping on tetrahedrite. A series of Cu12-xNixSb4S13-δ（x = 0.5, 0.7, 1.0, 1.5 and 2.0） compounds were synthesized by mechanical alloying combined with spark plasma sintering. It is found that the thermal conductivity sharply reduces with increasing Ni content over the entire temperature range,0.9 W m^-1K^-1, accompanied with an enhanced thermoelectric power factor. The model predicted that the reduced lattice thermal conductivity is attributed to mid-frequency phonon scattering, caused by precipitates and dislocations resulting from Ni doping. Consequently, a high ZT value up to 0.95 at 723 K was achieved for Cu11NiSb4S13-δ, corresponding to a ~46% increase over non-doped Cu12Sb4S13-δ. Furthermore,the cyclic measurement showed that the Ni-doped tetrahedrites displayed high chemical stability.展开更多
文摘O731 2000021386非简谐性离子晶格在光场中的能谱:动态斯塔克效应=Energy spectrum of anharmonic ionic-crystallattice in lightfield a dynamical Stark effect[刊,中]/欧发(华南理工大学应用物理系.广东,广州(510641)),何明高,吴福根(广东工业大学数理系.广东,广州(510090))//光学学报.-1999,19(7).-889-895以在偶极近似与旋转波近似下导出的哈密顿算符为基础,并以单模光频支声子与单模光场构成的共振耦合系统为简化模型,取得该耦合系统相互作用能谱的比较严格的解析解,同时还发现一种起源于声子-声子耦合的真空平移效应。图2参9(严寒)
文摘The coherent and incoherent interactions between discrete-soliton trains are numerically investigated in lightinduced two-dimensional photonic lattices. The solutions of discrete-soliton trains for diamond and square lattices are obtained by Petviashvili iteration method. It is found that for both the kinds of lattices, two in-phase （out- of-phase） discrete-soliton trains attract （repel） each other, and the intermediates are always accompanied with energy transfer. While the interaction forces between two incoherent discrete-soliton trains are always attractive.
文摘To understand the effect of the doping amount of Cu^2+ on the structure and reactivity of SnO2 in NOx-SCR with NH3, a series of Sn-Cu-O binary oxide catalysts with different Sn/Cu ratios have been prepared and thoroughly characterized. Using the XRD extrapolation method, the SnO2 lattice capacity for Cu^2+ cations is determined at 0.10 g Cu O per g of SnO2, equaling a Sn/Cu molar ratio of 84/16. Therefore, in a tetragonal rutile SnO2 lattice, only a maximum of 16% of the Sn4+ cations can be replaced by Cu^2+ to form a stable solid solution structure. If the Cu content is higher, Cu O will form on the catalyst surface, which has a negative effect on the reaction performance. For samples in a pure solid solution phase, the number of surface defects increase with increasing Cu content until it reaches the lattice capacity, as confirmed by Raman spectroscopy. As a result, the amounts of both active oxygen species and acidic sites on the surface, which critically determine the reaction performance, also increase and reach the maximum level for the catalyst with a Cu content close to the lattice capacity. A distinct lattice capacity threshold effect on the structure and reactivity of Sn-Cu binary oxide catalysts has been observed. A Sn-Cu catalyst with the best reaction performance can be obtained by doping the SnO2 matrix with the lattice capacity amount of Cu^2+.
文摘This paper describes the design of a FeWOx-based oxygen carrier for the chemical partial oxidation of methane(CLPOM).Thermodynamic screening and kinetic analyses both forecast the FeWOx-based oxygen carrier as a promising candidate for the production of syngas.The total methane conversion and syngas yield can be dramatically increased with this catalyst compared to the case with the unmodified WO3/SiO2,thereby enabling CLPOM with 62%methane conversion,93%CO gas-phase selectivity,94%H2 selectivity,and a 2.4 H2/CO ratio.The catalyst has the advantages of high availability of lattice oxygen to oxidize carbonaceous intermediates in time,together with the formation of an Fe-W alloy to promote the surface reaction.Consequently,it demonstrates excellent catalytic performance with no catalyst deactivation at 900°C and 1 atm.The excellent structural stability plays an essential role in CLPOM.As revealed via XPS and ICP,the phase segregation has not been observed due to the strong interaction between Fe and W,which resulted in the formation of the Fe-W alloy during the reduction processes and the match between the ion oxidation rates of the Fe and W ions in the oxidation stage.The results provide fundamental information on the reaction mechanism of FeWOx/SiO2,and present it as a promising candidate for CLPOM.
基金The project supported by National Natural Science Foundation of China under Grant No. 10371070
文摘Starting from a discrete spectral problem, a hierarchy of integrable lattice soliton equations is derived. It is shown that the hierarchy is completely integrable in the Liouville sense and possesses discrete bi-Hamiltonian structure. A new integrable symplectic map and finite-dimensional integrable systems are given by nonlinearization method. The binary Bargmann constraint gives rise to a Biicklund transformation for the resulting integrable lattice equations. At last, conservation laws of the hierarchy are presented.
基金Supported by the Research Work of Liaoning Provincial Development of Education under Grant No. 2008670
文摘In this paper, we extend a （2＋2）-dimensional continuous zero curvature equation to （2＋2）-dimensional discrete zero curvature equation, then a new （2＋2）-dimensional cubic Volterra lattice hierarchy is obtained. Fhrthermore, the integrable coupling systems of the （2＋2）-dimensional cubic Volterra lattice hierarchy and the generalized Toda lattice soliton equations are presented by using a Lie algebraic system sl（4）.
基金supported by the National Basic Research Program of China ("973" Project) (Grant Nos.2007CB307004,2006CB921607)the National Natural Science Foundation of China (Grant Nos.60776041,60976009,U0834001)
文摘We have fabricated a series of square-lattice hole photonic crystal (2PhC) arrays simultaneously at the un-current injection region on a special sample of GaN based light emitting diode (LED) by using focus ion beam milling (FIBM). The lattice constants of the 2PhC arrays vary from 230 to 1500 nm,while the 2PhC arrays have a constant area of about 9 μm×18 μm and a fixed depth of 150±10 nm which approaches but does not penetrate the active layer. Microscopic electroluminescence images and spectral measurements consistently confirm that the top emitting intensities from different 2PhCs are all enhanced compared with the unpatterned region. It is demonstrated that the output coupling of propagating guided modes is realized by the diffracted transmission of the 2PhCs. The enhancement factors of the guided modes compared with the unpatterned region are plotted as function of the lattice constant. It is found that the highest enhancements for the extraction of guided modes were obtained for the lattice constant of 230 and 460 nm of 2PhCs. The results are discussed by the two-dimensional rigorous coupled wave analysis (RCWA).
基金supported by the Basic Science Center Project of National Natural Science Foundation of China (51788104 and 11474176)Shenzhen Science and Technology Plan (JCYJ20150827165038323)
文摘Cu12Sb4S13 tetrahedrite has received great attention as an earth-abundant and environmental-friendly thermoelectric material. This work aims to uncover the thermoelectric performance-enhancing effect and the mechanism of nickel doping on tetrahedrite. A series of Cu12-xNixSb4S13-δ（x = 0.5, 0.7, 1.0, 1.5 and 2.0） compounds were synthesized by mechanical alloying combined with spark plasma sintering. It is found that the thermal conductivity sharply reduces with increasing Ni content over the entire temperature range,0.9 W m^-1K^-1, accompanied with an enhanced thermoelectric power factor. The model predicted that the reduced lattice thermal conductivity is attributed to mid-frequency phonon scattering, caused by precipitates and dislocations resulting from Ni doping. Consequently, a high ZT value up to 0.95 at 723 K was achieved for Cu11NiSb4S13-δ, corresponding to a ~46% increase over non-doped Cu12Sb4S13-δ. Furthermore,the cyclic measurement showed that the Ni-doped tetrahedrites displayed high chemical stability.
