Several important equilibrium Si isotope fractionation factors among minerals,organic molecules and the H_4SiO_4 solution are complemented to facilitate the explanation of the distributions of Si isotopes in Earth'...Several important equilibrium Si isotope fractionation factors among minerals,organic molecules and the H_4SiO_4 solution are complemented to facilitate the explanation of the distributions of Si isotopes in Earth's surface environments.The results reveal that,in comparison to aqueous H_4SiO_4,heavy Si isotopes will be significantly enriched in secondary silicate minerals.On the contrary,quadra-coordinated organosilicon complexes are enriched in light silicon isotope relative to the solution.The extent of ^(28)Si-enrichment in hyper-coordinated organosilicon complexes was found to be the largest.In addition,the large kinetic isotope effect associated with the polymerization of monosilicic acid and dimer was calculated,and the results support the previous statement that highly ^(28)Sienrichment in the formation of amorphous quartz precursor contributes to the discrepancy between theoretical calculations and field observations.With the equilibrium Si isotope fractionation factors provided here,Si isotope distributions in many of Earth's surface systems can be explained.For example,the change of bulk soil δ^(30)Si can be predicted as a concave pattern with respect to the weathering degree,with the minimum value where allophane completely dissolves and the total amount of sesquioxides and poorly crystalline minerals reaches their maximum.When,under equilibrium conditions,the well-crystallized clays start to precipitate from the pore solutions,the bulk soil δ^(30)Si will increase again and reach a constant value.Similarly,the precipitation of crystalline smectite and the dissolution of poorly crystalline kaolinite may explain the δ^(30)Si variations in the ground water profile.The equilibrium Si isotope fractionations among the quadracoordinated organosilicon complexes and the H_4SiO_4solution may also shed light on the Si isotope distributions in the Si-accumulating plants.展开更多
A new ternary cluster anion [Au（η^2-Sn2Sb2）2]^3- was synthesized and identified. The electronic structure of[Au（η^2-Sn2Sb2）2]^3- was analyzed by means of DFT calculations. The electronic energy and energy gap in...A new ternary cluster anion [Au（η^2-Sn2Sb2）2]^3- was synthesized and identified. The electronic structure of[Au（η^2-Sn2Sb2）2]^3- was analyzed by means of DFT calculations. The electronic energy and energy gap indicate that [Au（η^2-Sn2Sb2）2]^3- features coplanar faces AuSn_2 in which gold is directly coordinated by four tin atoms. Molecule orbital composition analysis indicates that d-orbital in Au atom contributes to bonding. Charge decomposition analysis（CDA） shows that electron donation and back donation are the key factors forming planar conformation of Au atom in [Au（η^2-Sn2Sb2）2]^3-. Meanwhile, the calculated Mayer bond order indicates relatively weaker interactions between Au and coordinated tetrahedral [Sn2Sb2]^2-.展开更多
In accordance with the specific deployment way of infrastructure and data exchanging technology in the Internet of vehicles(IoV),the acquiring and calculating method for three basic traffic flow parameters in IoV scen...In accordance with the specific deployment way of infrastructure and data exchanging technology in the Internet of vehicles(IoV),the acquiring and calculating method for three basic traffic flow parameters in IoV scenarios,including traffic flow,speed and density,was researched.Considering the complexity of traffic flow and fuzziness of human thinking,fuzzy c-means clustering algorithm based on the genetic algorithm(GA-FCM) was adopted in soft classification of urban road traffic conditions.Genetic algorithm(GA) introduced into fuzzy clustering could avoid fuzzy c-means(FCM) algorithm converging to the local infinitesimal point,which made the cluster result more precise.By means of computer simulation,data exchanging environment in IoV was imitated,and then test data set was divided into four parts.The simulation indicates that the identification method is feasible and effective for urban road traffic conditions in IoV scenarios.展开更多
We exploited a hydrogen-passivated germanium atomic cluster（Ge10H16） as a model to study the mechanism of lithium alloying with germanium. Based on the density functional theory, the electronic and crystal structure...We exploited a hydrogen-passivated germanium atomic cluster（Ge10H16） as a model to study the mechanism of lithium alloying with germanium. Based on the density functional theory, the electronic and crystal structures of lithium-alloyed Ge10H16 were investigated. The theoretical results indicate that the alloying of lithium with Ge10H16 will weaken the germanium-hydrogen bond and repel the closest germanium atom away from the alloyed lithium atom. Based on the maps of the electron density distribution, the nature of the lithium-germanium chemical bond was analyzed. Moreover, the diffusion process of the lithium on the Ge10H16 cluster was detected, which suggested that there is a close relationship between the diffusion barriers and the coordination number around the lithium atom.展开更多
基金the funding support from the 973 Program(2014CB440904)CAS/SAFEA International Partnership Program for Creative Research Teams(Intraplate Mineralization Research Team,KZZD-EW-TZ-20)Chinese NSF projects(41173023,41225012,41490635,41530210)
文摘Several important equilibrium Si isotope fractionation factors among minerals,organic molecules and the H_4SiO_4 solution are complemented to facilitate the explanation of the distributions of Si isotopes in Earth's surface environments.The results reveal that,in comparison to aqueous H_4SiO_4,heavy Si isotopes will be significantly enriched in secondary silicate minerals.On the contrary,quadra-coordinated organosilicon complexes are enriched in light silicon isotope relative to the solution.The extent of ^(28)Si-enrichment in hyper-coordinated organosilicon complexes was found to be the largest.In addition,the large kinetic isotope effect associated with the polymerization of monosilicic acid and dimer was calculated,and the results support the previous statement that highly ^(28)Sienrichment in the formation of amorphous quartz precursor contributes to the discrepancy between theoretical calculations and field observations.With the equilibrium Si isotope fractionation factors provided here,Si isotope distributions in many of Earth's surface systems can be explained.For example,the change of bulk soil δ^(30)Si can be predicted as a concave pattern with respect to the weathering degree,with the minimum value where allophane completely dissolves and the total amount of sesquioxides and poorly crystalline minerals reaches their maximum.When,under equilibrium conditions,the well-crystallized clays start to precipitate from the pore solutions,the bulk soil δ^(30)Si will increase again and reach a constant value.Similarly,the precipitation of crystalline smectite and the dissolution of poorly crystalline kaolinite may explain the δ^(30)Si variations in the ground water profile.The equilibrium Si isotope fractionations among the quadracoordinated organosilicon complexes and the H_4SiO_4solution may also shed light on the Si isotope distributions in the Si-accumulating plants.
基金supported by National Natural Science Foundation of China(21171162).Thanks for Computing center of Jilin Province
文摘A new ternary cluster anion [Au（η^2-Sn2Sb2）2]^3- was synthesized and identified. The electronic structure of[Au（η^2-Sn2Sb2）2]^3- was analyzed by means of DFT calculations. The electronic energy and energy gap indicate that [Au（η^2-Sn2Sb2）2]^3- features coplanar faces AuSn_2 in which gold is directly coordinated by four tin atoms. Molecule orbital composition analysis indicates that d-orbital in Au atom contributes to bonding. Charge decomposition analysis（CDA） shows that electron donation and back donation are the key factors forming planar conformation of Au atom in [Au（η^2-Sn2Sb2）2]^3-. Meanwhile, the calculated Mayer bond order indicates relatively weaker interactions between Au and coordinated tetrahedral [Sn2Sb2]^2-.
基金the Humanity and Social Science Youth Foundation of Ministry of Education in China(No.12YJC630200)Natural Science Foundations of Gansu Province in China(Nos.145RJZA190,1308RJYA042)the Social Science Planning Project of Gansu Province in China(No.13YD066)
文摘In accordance with the specific deployment way of infrastructure and data exchanging technology in the Internet of vehicles(IoV),the acquiring and calculating method for three basic traffic flow parameters in IoV scenarios,including traffic flow,speed and density,was researched.Considering the complexity of traffic flow and fuzziness of human thinking,fuzzy c-means clustering algorithm based on the genetic algorithm(GA-FCM) was adopted in soft classification of urban road traffic conditions.Genetic algorithm(GA) introduced into fuzzy clustering could avoid fuzzy c-means(FCM) algorithm converging to the local infinitesimal point,which made the cluster result more precise.By means of computer simulation,data exchanging environment in IoV was imitated,and then test data set was divided into four parts.The simulation indicates that the identification method is feasible and effective for urban road traffic conditions in IoV scenarios.
基金financially supported by the Projects of Undergraduate Innovation&entrepreneurship Training Plans of Quanzhou Normal University(No.201310399008)Quanzhou‘‘Tong-Jiang Scholar"program,Fujian‘‘MinJiang Scholar"program,program for New Century Excellent Talents in University(No.NCET-13-0879)the Education and Scientific Research Foundation(Class A)for Young Teachers of Education Bureau of Fujian Province,China(No.JA13263)
文摘We exploited a hydrogen-passivated germanium atomic cluster（Ge10H16） as a model to study the mechanism of lithium alloying with germanium. Based on the density functional theory, the electronic and crystal structures of lithium-alloyed Ge10H16 were investigated. The theoretical results indicate that the alloying of lithium with Ge10H16 will weaken the germanium-hydrogen bond and repel the closest germanium atom away from the alloyed lithium atom. Based on the maps of the electron density distribution, the nature of the lithium-germanium chemical bond was analyzed. Moreover, the diffusion process of the lithium on the Ge10H16 cluster was detected, which suggested that there is a close relationship between the diffusion barriers and the coordination number around the lithium atom.
