The orientation indices and group corresponding indices of 210 molecular structures of polychlorinated biphenyls(PCBs)and biphenyl were calculated.By combining these indices with seven thermodynamic properties reporte...The orientation indices and group corresponding indices of 210 molecular structures of polychlorinated biphenyls(PCBs)and biphenyl were calculated.By combining these indices with seven thermodynamic properties reported in literature of such PCBs, including standard entropy (S0),standard enthalpy(H0),standard free energy(G0),total energy(ET),thermal energy correction(Eth),zero-point vibration energy(Ezpv)and constant volume molar heat capacity (C0V), a series of quantitative structure property relationship (QSPR) equations were built up by the multiple regression method.All the correlation coefficients were larger than 0.99.These models could better explain the change of thermodynamic properties for the PCBs,and the QSPR models had high correlation coefficients,good stability and good predictability.A modified leave-one-out procedure test was performed to validate model robustness,and predict the S0,H0,G0,ET,Eth,Ezpv,C0V of other PCBs molecules by the regression equation,and the error analysis were discussed.The results showed better agreement between the values predicted by the model developed and the observed values of the thermodynamic properties.展开更多
Crop water stress index(CWSI)is widely used for efficient irrigation management.Precise canopy temperature(T_(c))measurement is necessary to derive a reliable CWSI.The objective of this research was to investigate the...Crop water stress index(CWSI)is widely used for efficient irrigation management.Precise canopy temperature(T_(c))measurement is necessary to derive a reliable CWSI.The objective of this research was to investigate the influences of atmospheric conditions,settled height,view angle of infrared thermography,and investigating time of temperature measuring on the performance of the CWSI.Three irrigation treatments were used to create different soil water conditions during the 2020-2021 and 2021-2022 winter wheat-growing seasons.The CWSI was calculated using the CWSI-E(an empirical approach)and CWSI-T(a theoretical approach)based on the T_(c).Weather conditions were recorded continuously throughout the experimental period.The results showed that atmospheric conditions influenced the estimation of the CWSI;when the vapor pressure deficit(VPD)was>2000 Pa,the estimated CWSI was related to soil water conditions.The height of the installed infrared thermograph influenced the T_(c)values,and the differences among the T_(c)values measured at height of 3,5,and 10 m was smaller in the afternoon than in the morning.However,the lens of the thermometer facing south recorded a higher T_(c)than those facing east or north,especially at a low height,indicating that the direction of the thermometer had a significant influence on T_(c).There was a large variation in CWSI derived at different times of the day,and the midday measurements(12:00-15:00)were the most reliable for estimating CWSI.Negative linear relationships were found between the transpiration rate and CWSI-E(R^(2)of 0.3646-0.5725)and CWSI-T(R^(2)of 0.5407-0.7213).The relations between fraction of available soil water(FASW)with CWSI-T was higher than that with CWSI-E,indicating CWSI-T was more accurate for predicting crop water status.In addition,The R^(2)between CWSI-T and FASW at 14:00 was higher than that at other times,indicating that 14:00 was the optimal time for using the CWSI for crop water status monitoring.Relative higher yield of winter wheat was obtained with average seasonal values of CWSI-E and CWSI-T around 0.23 and 0.25-0.26,respectively.The CWSI-E values were more easily influenced by meteorological factors and the timing of the measurements,and using the theoretical approach to derive the CWSI was recommended for precise irrigation water management.展开更多
Polychlorinated diphenyl ethers(PCDEs) are listed as the so-called persistent pollutants.Atomic characteristic values of all 209 possible molecular structure patterns of PCDEs were calculated,then a new connectivity i...Polychlorinated diphenyl ethers(PCDEs) are listed as the so-called persistent pollutants.Atomic characteristic values of all 209 possible molecular structure patterns of PCDEs were calculated,then a new connectivity index,orientating corresponding index was calculated with the technique of molecule graphics.The orientating corresponding index was combined with five observed thermodynamic properties of PCDEs,i.e.molecular mean polarizability,standard enthalpy,free energy,heat capacity at constant volume and standard entropy,and fifteen quantitative structure-property relationship(QSPR) models(r>0.99)were obtained with the unitary linear regression method,and the relative mean deviations were 1.02%,0.48%,0.48%,0.22% and 0.90%,respectively.In order to test the stability and prediction ability of each model,the jackknifed cross validation was performed and good results(r>0.99)were obtained.These models can better elucidate the change of the thermodynamic properties for the PCDEs,and the QSPR models have satisfactory stability and good predictability.展开更多
By comparing the entropy and the conditional entropy in a marker, an entropy-based index has been presented for fine-scale linkage disequilibrium gene mapping using high-density marker maps for human disease genes. Th...By comparing the entropy and the conditional entropy in a marker, an entropy-based index has been presented for fine-scale linkage disequilibrium gene mapping using high-density marker maps for human disease genes. The index can quantify the level of linkage disequilibrium （LD） between the marker and the disease susceptibility locus （DSL） of genes. The advantage of using the index is attributed to the fact that it does not depend on marker allele frequencies across loci. Moreover, it is parallel to Hardy-Weinberg disequilibrium （HWD） measure for DSL fine mapping. Through various simulations, the fine mapping perform- ances of the proposed entropy-based index was extensively investigated under various genetic parameters. The results show that the index presented is both robust and powerful for DSL mapping in genes.展开更多
文摘The orientation indices and group corresponding indices of 210 molecular structures of polychlorinated biphenyls(PCBs)and biphenyl were calculated.By combining these indices with seven thermodynamic properties reported in literature of such PCBs, including standard entropy (S0),standard enthalpy(H0),standard free energy(G0),total energy(ET),thermal energy correction(Eth),zero-point vibration energy(Ezpv)and constant volume molar heat capacity (C0V), a series of quantitative structure property relationship (QSPR) equations were built up by the multiple regression method.All the correlation coefficients were larger than 0.99.These models could better explain the change of thermodynamic properties for the PCBs,and the QSPR models had high correlation coefficients,good stability and good predictability.A modified leave-one-out procedure test was performed to validate model robustness,and predict the S0,H0,G0,ET,Eth,Ezpv,C0V of other PCBs molecules by the regression equation,and the error analysis were discussed.The results showed better agreement between the values predicted by the model developed and the observed values of the thermodynamic properties.
基金supported by the Project of State Grid Hebei Electric Power Co.,Ltd.(SGHEYX00SCJS2100077).
文摘Crop water stress index(CWSI)is widely used for efficient irrigation management.Precise canopy temperature(T_(c))measurement is necessary to derive a reliable CWSI.The objective of this research was to investigate the influences of atmospheric conditions,settled height,view angle of infrared thermography,and investigating time of temperature measuring on the performance of the CWSI.Three irrigation treatments were used to create different soil water conditions during the 2020-2021 and 2021-2022 winter wheat-growing seasons.The CWSI was calculated using the CWSI-E(an empirical approach)and CWSI-T(a theoretical approach)based on the T_(c).Weather conditions were recorded continuously throughout the experimental period.The results showed that atmospheric conditions influenced the estimation of the CWSI;when the vapor pressure deficit(VPD)was>2000 Pa,the estimated CWSI was related to soil water conditions.The height of the installed infrared thermograph influenced the T_(c)values,and the differences among the T_(c)values measured at height of 3,5,and 10 m was smaller in the afternoon than in the morning.However,the lens of the thermometer facing south recorded a higher T_(c)than those facing east or north,especially at a low height,indicating that the direction of the thermometer had a significant influence on T_(c).There was a large variation in CWSI derived at different times of the day,and the midday measurements(12:00-15:00)were the most reliable for estimating CWSI.Negative linear relationships were found between the transpiration rate and CWSI-E(R^(2)of 0.3646-0.5725)and CWSI-T(R^(2)of 0.5407-0.7213).The relations between fraction of available soil water(FASW)with CWSI-T was higher than that with CWSI-E,indicating CWSI-T was more accurate for predicting crop water status.In addition,The R^(2)between CWSI-T and FASW at 14:00 was higher than that at other times,indicating that 14:00 was the optimal time for using the CWSI for crop water status monitoring.Relative higher yield of winter wheat was obtained with average seasonal values of CWSI-E and CWSI-T around 0.23 and 0.25-0.26,respectively.The CWSI-E values were more easily influenced by meteorological factors and the timing of the measurements,and using the theoretical approach to derive the CWSI was recommended for precise irrigation water management.
文摘Polychlorinated diphenyl ethers(PCDEs) are listed as the so-called persistent pollutants.Atomic characteristic values of all 209 possible molecular structure patterns of PCDEs were calculated,then a new connectivity index,orientating corresponding index was calculated with the technique of molecule graphics.The orientating corresponding index was combined with five observed thermodynamic properties of PCDEs,i.e.molecular mean polarizability,standard enthalpy,free energy,heat capacity at constant volume and standard entropy,and fifteen quantitative structure-property relationship(QSPR) models(r>0.99)were obtained with the unitary linear regression method,and the relative mean deviations were 1.02%,0.48%,0.48%,0.22% and 0.90%,respectively.In order to test the stability and prediction ability of each model,the jackknifed cross validation was performed and good results(r>0.99)were obtained.These models can better elucidate the change of the thermodynamic properties for the PCDEs,and the QSPR models have satisfactory stability and good predictability.
文摘By comparing the entropy and the conditional entropy in a marker, an entropy-based index has been presented for fine-scale linkage disequilibrium gene mapping using high-density marker maps for human disease genes. The index can quantify the level of linkage disequilibrium （LD） between the marker and the disease susceptibility locus （DSL） of genes. The advantage of using the index is attributed to the fact that it does not depend on marker allele frequencies across loci. Moreover, it is parallel to Hardy-Weinberg disequilibrium （HWD） measure for DSL fine mapping. Through various simulations, the fine mapping perform- ances of the proposed entropy-based index was extensively investigated under various genetic parameters. The results show that the index presented is both robust and powerful for DSL mapping in genes.
