基于传统面向对象方法,提出了一种基于最优特征空间的损毁建筑物信息提取方法。采用ESP(Estimate of Scale Parameter)工具对图像进行最优尺度分割,之后通过选取样本,计算各类地物距离矩阵和最小分离距离寻求最优特征空间,最后运用最优...基于传统面向对象方法,提出了一种基于最优特征空间的损毁建筑物信息提取方法。采用ESP(Estimate of Scale Parameter)工具对图像进行最优尺度分割,之后通过选取样本,计算各类地物距离矩阵和最小分离距离寻求最优特征空间,最后运用最优特征空间对震后损毁建筑物影像进行提取实验,在QuickBird影像中提取总体精度达到了83.1%, Kappa系数达到了0.813,在无人机影像中提取总体精度为92.9%, Kappa系数达到了0.940。本文建立的提取方法与传统分类决策树方法相比,其提取精度和效率都有较大提高,在损毁建筑物信息提取方面具有较好的推广价值。展开更多
The adsorption of NO on the M/c-ZrOu（110） （M = Ru, Rh） surface has been studied with periodic slab model by PWgl approach of GGA within the framework of density functional theory. The results of geometry optimizat...The adsorption of NO on the M/c-ZrOu（110） （M = Ru, Rh） surface has been studied with periodic slab model by PWgl approach of GGA within the framework of density functional theory. The results of geometry optimization indicated that the hollow site is energetically stable for Ru and Rh atoms＇ adsorption on the c-ZrO2（110） surface with adsorption energies of 207.4 and 106.3 kJ/mol, respectively. When NO is adsorbed on the M/ZrO2（110） surface, the N-down adsorption is the most stable. We also studied the adsorption of double NO on the M/c-ZrOu（110） surface. Complete linear synchronous transit and quadratic synchronous transit approaches were used to search the transition state for dissociation reaction. NO has two possible dissociation passways： （1） 2NO → N2 （g） ＋ 20 （ads）, （2） 2NO→ N20 （g） ＋ O （ads）, and the former is easier than the latter based on the calculation results.展开更多
We have investigated the reaction mechanism for N20 decomposition on Cu13 via density functional theory. It is found that N20 decomposition on the cluster is more prone to be along the Eley-Rideal （ER） pathway in co...We have investigated the reaction mechanism for N20 decomposition on Cu13 via density functional theory. It is found that N20 decomposition on the cluster is more prone to be along the Eley-Rideal （ER） pathway in comparison with the Langmuir-Hinshelwood （LH） channel. There exists structural relaxation for Cu13 cluster in the reaction, which may influence the catalytic activity of cluster for the subsequent N2O decomposition. The core atom in the Cu13 cluster is substituted with the Fe, Co, or Ni to enhance structural stability and prevent from the obvious configuration relaxation in the reaction. Note that these bimetallic clusters are of icosahedra as the Cu13. They have activities for N2O dissociation along ER pathway and the heteroatorn in the cluster can prevent configuration from relaxation. Finally, the Ni@Cu12 cluster can be as a superior catalyst in a complete catalytic cycle via comparison in this study.展开更多
The gold atoms on the Au20 cluster had been substituted by the palladium and platinum atoms to obtain the doped clusters with more stable geometries as a function of the bind energy and interaction energy in the previ...The gold atoms on the Au20 cluster had been substituted by the palladium and platinum atoms to obtain the doped clusters with more stable geometries as a function of the bind energy and interaction energy in the previous study. Therefore, we investigated the catalytic activities of the AuPd and AuPt clusters for CO oxidation along the Langmuir-Hinshelwood mechanism. It is found that the coadsorption of CO and O2 on the doped clusters is obviously stronger than on the Au20 cluster, especially on the doped atom, which makes potential energy of the transition state lower than the total energy of the reactants so that it can promote CO oxidation. The reaction on these doped clusters with the heteroatom on the vertex is more difficult. However, the AuPd(S) is more prone to catalyzing the CO oxidation, in which the rate-limiting step has the lower energy barrier of 38.84 kJ/mol for this study. Therefore, the single atom can be modified to change the catalytic activity of the cluster for the CO oxidation. Meanwhile, the different sites on the clusters have different strengths of activity for the reaction.展开更多
Defect engineering has being regarded as one of the effective ways to regulate chemical and electronic structure of semiconductors.Recently,our collaborative work has shown experimentally that carbon vacancy on polyme...Defect engineering has being regarded as one of the effective ways to regulate chemical and electronic structure of semiconductors.Recently,our collaborative work has shown experimentally that carbon vacancy on polymeric carbon nitride(CV)can greatly improve the CO2 to CO conversion with a 45-fold improvement over the polymeric carbon nitride(Angew.Chem.Int.Ed.,2019,58,1134).In order to clarify the detailed mechanism of promotion,we have systematically studied the electronic properties of CV and hydrogenated CV(CV+H)as well as the effective CO2 reduction reaction through density functional theory calculations.We found that it is the synergistic effect for the CO2 reduction reaction in the CV systems,as the onset potentials of several CVs are much lower than that of the polymeric carbon nitride.In particular,the onset potentials of CV1,CV2,and CV2+H are around 0.9~1.5 eV with a strong chemisorbed CO2 on them.Combined with the analysis of the electronic properties,our results confirm that defect engineering increases the lifetime of photo-generated charges,improves photocatalytic activity,and promotes the CO2 reduction reaction on the defected polymeric carbon nitrides.展开更多
基金Supported by NNSFC(10676007,90922022)Foundation of State Key Laboratory of Coal Combustion(FSKLCC0814)+1 种基金NCETFJ(2006-HX-103,2006-HX-97) Foundation of Fuzhou University(2008-XQ-07,XRC-0732)
文摘The adsorption of NO on the M/c-ZrOu（110） （M = Ru, Rh） surface has been studied with periodic slab model by PWgl approach of GGA within the framework of density functional theory. The results of geometry optimization indicated that the hollow site is energetically stable for Ru and Rh atoms＇ adsorption on the c-ZrO2（110） surface with adsorption energies of 207.4 and 106.3 kJ/mol, respectively. When NO is adsorbed on the M/ZrO2（110） surface, the N-down adsorption is the most stable. We also studied the adsorption of double NO on the M/c-ZrOu（110） surface. Complete linear synchronous transit and quadratic synchronous transit approaches were used to search the transition state for dissociation reaction. NO has two possible dissociation passways： （1） 2NO → N2 （g） ＋ 20 （ads）, （2） 2NO→ N20 （g） ＋ O （ads）, and the former is easier than the latter based on the calculation results.
基金supported by the Natural Science Foundation of Fujian Province(2012J01041)
文摘We have investigated the reaction mechanism for N20 decomposition on Cu13 via density functional theory. It is found that N20 decomposition on the cluster is more prone to be along the Eley-Rideal （ER） pathway in comparison with the Langmuir-Hinshelwood （LH） channel. There exists structural relaxation for Cu13 cluster in the reaction, which may influence the catalytic activity of cluster for the subsequent N2O decomposition. The core atom in the Cu13 cluster is substituted with the Fe, Co, or Ni to enhance structural stability and prevent from the obvious configuration relaxation in the reaction. Note that these bimetallic clusters are of icosahedra as the Cu13. They have activities for N2O dissociation along ER pathway and the heteroatorn in the cluster can prevent configuration from relaxation. Finally, the Ni@Cu12 cluster can be as a superior catalyst in a complete catalytic cycle via comparison in this study.
基金Supported by the National Natural Science Foundation of China(Nos.51574090,21773030)Natural Science Foundation of Fujian Province(2017J01409)
文摘The gold atoms on the Au20 cluster had been substituted by the palladium and platinum atoms to obtain the doped clusters with more stable geometries as a function of the bind energy and interaction energy in the previous study. Therefore, we investigated the catalytic activities of the AuPd and AuPt clusters for CO oxidation along the Langmuir-Hinshelwood mechanism. It is found that the coadsorption of CO and O2 on the doped clusters is obviously stronger than on the Au20 cluster, especially on the doped atom, which makes potential energy of the transition state lower than the total energy of the reactants so that it can promote CO oxidation. The reaction on these doped clusters with the heteroatom on the vertex is more difficult. However, the AuPd(S) is more prone to catalyzing the CO oxidation, in which the rate-limiting step has the lower energy barrier of 38.84 kJ/mol for this study. Therefore, the single atom can be modified to change the catalytic activity of the cluster for the CO oxidation. Meanwhile, the different sites on the clusters have different strengths of activity for the reaction.
基金financially supported by the National Natural Science Foundation of China(21973014,21773030)the Award Program of Minjiang Scholar Professorship for financial support。
文摘Defect engineering has being regarded as one of the effective ways to regulate chemical and electronic structure of semiconductors.Recently,our collaborative work has shown experimentally that carbon vacancy on polymeric carbon nitride(CV)can greatly improve the CO2 to CO conversion with a 45-fold improvement over the polymeric carbon nitride(Angew.Chem.Int.Ed.,2019,58,1134).In order to clarify the detailed mechanism of promotion,we have systematically studied the electronic properties of CV and hydrogenated CV(CV+H)as well as the effective CO2 reduction reaction through density functional theory calculations.We found that it is the synergistic effect for the CO2 reduction reaction in the CV systems,as the onset potentials of several CVs are much lower than that of the polymeric carbon nitride.In particular,the onset potentials of CV1,CV2,and CV2+H are around 0.9~1.5 eV with a strong chemisorbed CO2 on them.Combined with the analysis of the electronic properties,our results confirm that defect engineering increases the lifetime of photo-generated charges,improves photocatalytic activity,and promotes the CO2 reduction reaction on the defected polymeric carbon nitrides.
