A novel quantitative structure-property relationship （QSPR） model for estimating the solution surface tension of 92 organic compounds at 20℃ was developed based on newly introduced atom-type topological indices. Th...A novel quantitative structure-property relationship （QSPR） model for estimating the solution surface tension of 92 organic compounds at 20℃ was developed based on newly introduced atom-type topological indices. The data set contained non-polar and polar liquids, and saturated and unsaturated compounds. The regression analysis shows that excellent result is obtained with multiple linear regression. The predictive power of the proposed model was discussed using the leave-one-out （LOO） cross-validated （CV） method. The correlation coefficient （R） and the leave-one-out cross-validation correlation coefficient （Rcv） of multiple linear regression model are 0.991 4 and 0.991 3, respectively. The new model gives the average absolute relative deviation of 1.81% for 92 substances. The result demonstrates that novel topological indices based on the equilibrium electro-negativity of atom and the relative bond length are useful model parameters for QSPR analysis of compounds.展开更多
Afforestation is helpful to improve soil functions and increase soil organic carbon(SOC)sequestration in semiarid deserts.However,the fine-scale(around a single plant)spatial distribution of SOC and its liable organic...Afforestation is helpful to improve soil functions and increase soil organic carbon(SOC)sequestration in semiarid deserts.However,the fine-scale(around a single plant)spatial distribution of SOC and its liable organic carbon(LOC)fractions after afforestation in semiarid deserts are poorly understood.Pinus sylvestris and Salix psammophila afforested on shifting sandy land(Sland)were selected to quantify fine-scale(at 20,80,150 and 240 cm away from the trees)spatial distribution of SOC and its LOC fractions in the southeast edge of Mu Us Desert,China.The results showed that the afforested S.psammophila and P.sylvestris significantly increased SOC,total nitrogen,dissolved organic carbon,microbial biomass carbon and readily oxidized organic carbon(ROOC).At 20 cm distance,SOC storage of P.sylvestris was 27.21%higher than S.psammophila in 0-100 cm soil layers,and SOC storage of S.psammophila at 80 and 150 cm distances was 5.50%and 5.66%higher than P.sylvestris,respectively.Compared with Sland,SOC storage under S.psammophila and P.sylvestris significantly increased by 94.90%,39.50%,27.10%and 18.50%at 20,80,150 and 240 cm distance,respectively.ROOC accounted for 14.09%and 18.93%of SOC under S.psammophila and P.sylvestris,respectively.Our results suggest that afforestation can promote SOC accumulation at different distances from the plants,and that P.sylvestris allocates more organic matter to the closer soil compared with S.psammophila(<80 cm from the tree).展开更多
Based on the traditional finite volume method, a new numerical technique is presented for the transient temperature field prediction with interval uncertainties in both the physical parameters and initial/boundary con...Based on the traditional finite volume method, a new numerical technique is presented for the transient temperature field prediction with interval uncertainties in both the physical parameters and initial/boundary conditions. New stability theory applicable to interval discrete schemes is developed. Interval ranges of the uncertain temperature field can be approximately yielded by two kinds of parameter perturbation methods. Different order Neumann series are adopted to approximate the interval matrix inverse. By comparing the results with traditional Monte Carlo simulation, a numerical example is given to demonstrate the feasibility and effectiveness of the proposed model and methods.展开更多
基金Projects(20775010,21075011) supported by the National Natural Science Foundation of ChinaProject(2008AA05Z405) supported by the National High Technology Research and Development Program of China+2 种基金Project(09JJ3016) supported by Hunan Provincial Natural Science Foundation,ChinaProject(09C066) supported by Scientific Research Fund of Hunan Provincial Education Department,ChinaProject(2010CL01) supported by the Foundation of Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation,China
文摘A novel quantitative structure-property relationship （QSPR） model for estimating the solution surface tension of 92 organic compounds at 20℃ was developed based on newly introduced atom-type topological indices. The data set contained non-polar and polar liquids, and saturated and unsaturated compounds. The regression analysis shows that excellent result is obtained with multiple linear regression. The predictive power of the proposed model was discussed using the leave-one-out （LOO） cross-validated （CV） method. The correlation coefficient （R） and the leave-one-out cross-validation correlation coefficient （Rcv） of multiple linear regression model are 0.991 4 and 0.991 3, respectively. The new model gives the average absolute relative deviation of 1.81% for 92 substances. The result demonstrates that novel topological indices based on the equilibrium electro-negativity of atom and the relative bond length are useful model parameters for QSPR analysis of compounds.
基金supported by the National Natural Science Foundation of China(41877541,41471222).
文摘Afforestation is helpful to improve soil functions and increase soil organic carbon(SOC)sequestration in semiarid deserts.However,the fine-scale(around a single plant)spatial distribution of SOC and its liable organic carbon(LOC)fractions after afforestation in semiarid deserts are poorly understood.Pinus sylvestris and Salix psammophila afforested on shifting sandy land(Sland)were selected to quantify fine-scale(at 20,80,150 and 240 cm away from the trees)spatial distribution of SOC and its LOC fractions in the southeast edge of Mu Us Desert,China.The results showed that the afforested S.psammophila and P.sylvestris significantly increased SOC,total nitrogen,dissolved organic carbon,microbial biomass carbon and readily oxidized organic carbon(ROOC).At 20 cm distance,SOC storage of P.sylvestris was 27.21%higher than S.psammophila in 0-100 cm soil layers,and SOC storage of S.psammophila at 80 and 150 cm distances was 5.50%and 5.66%higher than P.sylvestris,respectively.Compared with Sland,SOC storage under S.psammophila and P.sylvestris significantly increased by 94.90%,39.50%,27.10%and 18.50%at 20,80,150 and 240 cm distance,respectively.ROOC accounted for 14.09%and 18.93%of SOC under S.psammophila and P.sylvestris,respectively.Our results suggest that afforestation can promote SOC accumulation at different distances from the plants,and that P.sylvestris allocates more organic matter to the closer soil compared with S.psammophila(<80 cm from the tree).
基金supported by the National Special Fund for Major Research Instrument Development(Grant No.2011YQ140145)111 Project(Grant No.B07009)+1 种基金National Natural Science Foundation of China(Grant No.11002013)Defense Industrial Technology Development Program(Grant Nos.A2120110001 and B2120110011)
文摘Based on the traditional finite volume method, a new numerical technique is presented for the transient temperature field prediction with interval uncertainties in both the physical parameters and initial/boundary conditions. New stability theory applicable to interval discrete schemes is developed. Interval ranges of the uncertain temperature field can be approximately yielded by two kinds of parameter perturbation methods. Different order Neumann series are adopted to approximate the interval matrix inverse. By comparing the results with traditional Monte Carlo simulation, a numerical example is given to demonstrate the feasibility and effectiveness of the proposed model and methods.
