A field experiment was employed to study the degradation of triadimefon and difenoconazole residues in strawberry and soil. The results showed that the degradation of both the two kinds of pesticides was in accordance...A field experiment was employed to study the degradation of triadimefon and difenoconazole residues in strawberry and soil. The results showed that the degradation of both the two kinds of pesticides was in accordance with the first order kinetic equation. The half-lives of difenoconazole in strawberry fruit, strawberry stem leaf and soil were 4.09, 8.21 and 13.38 d, respectively; and the half-lives of triadimefon in strawberry fruit, strawberry stem and leaf and soil were 3.38, 5.31 and 15.64 d, respectively. The maximum residue limit （MRL） of difenoconazole in strawberry was recommended as 0.5 mg/kg, and 10% difenoconazole WG and 20% triadimefon EC should be applied four times with a safety interval of 7 d according to the amounts of 100 and 60 g a. i./hm2,respectively.展开更多
Four kinds of plant materials (astragalus, azolla, rice straw and water hyacinth) were allowed to decompose for 10 years in two soils with different mineralogical characteristics in fields under upland and submerged c...Four kinds of plant materials (astragalus, azolla, rice straw and water hyacinth) were allowed to decompose for 10 years in two soils with different mineralogical characteristics in fields under upland and submerged conditions. Greater amounts of C and N from azolla were retained in soils throughout the 10-year experimental period compared to those from the other plant materials. The residual C Of all the plant materials in the two soils under upland conditions mineralized st rates corresponding to half-lives between 4.4-6.6 years,while the corresponding figures for thine under submerged conditions were between 6.5-13.1 years. Minerallization of residual organic N followed the same pattern as residual C. Compared to residual C, however, the mineralization rates of residual organic N in most cases were significantly lower and the percentages of added N regained in sons were higher. More N from plat materials was retained in the yellow-brown soil than in the red soil, but no consistent differences in the amounts of C from plant materials and in the mineralization rates of both residual C and residual organic N between the two soils could be found.展开更多
In order to improve the effectiveness of traditional time domain identification methods in identifying damping ratios, a new damping ratio identification method based on pattern search is proposed by fluctuating the r...In order to improve the effectiveness of traditional time domain identification methods in identifying damping ratios, a new damping ratio identification method based on pattern search is proposed by fluctuating the reliable natural frequency obtained through traditional time domain identification methods by about 10% to build the boundary conditions, using all the initial identification results to establish the free decay response of the system, and using the pattern search method to correct the initial identification results with the residual sum of squares between the free decay response and the actually measured free-decay signal as the objective function. The proposed method deals with the actually measured free-decay signal with curve fitting and avoids enlarging the identified error caused by intermediate conversion, so it can effectively improve the identified accuracy of damping ratios. Simulations for a room-sized vibration isolation foundation show that the relative errors of analyzed three damping ratios are down to 1.05%, 1.51% and 3.7% by the proposed method from 8.42%, 5.85% and 8.5% by STD method when the noise level is 10%.展开更多
基金Supported by Tripartite Joint Fund of Science and Technology Department of Guizhou Province(LH[2016]7278)Agricultural Science and Technology Project of Science and Technology Department of Guizhou Province(NZ[2013]3029)+1 种基金Tripartite Joint Fund of Science and Technology Department of Guizhou Province(Key Project)(JLKA[2012]03)Natural Science Research Project of Department of Education of Guizhou Province(2011054)~~
文摘A field experiment was employed to study the degradation of triadimefon and difenoconazole residues in strawberry and soil. The results showed that the degradation of both the two kinds of pesticides was in accordance with the first order kinetic equation. The half-lives of difenoconazole in strawberry fruit, strawberry stem leaf and soil were 4.09, 8.21 and 13.38 d, respectively; and the half-lives of triadimefon in strawberry fruit, strawberry stem and leaf and soil were 3.38, 5.31 and 15.64 d, respectively. The maximum residue limit （MRL） of difenoconazole in strawberry was recommended as 0.5 mg/kg, and 10% difenoconazole WG and 20% triadimefon EC should be applied four times with a safety interval of 7 d according to the amounts of 100 and 60 g a. i./hm2,respectively.
文摘Four kinds of plant materials (astragalus, azolla, rice straw and water hyacinth) were allowed to decompose for 10 years in two soils with different mineralogical characteristics in fields under upland and submerged conditions. Greater amounts of C and N from azolla were retained in soils throughout the 10-year experimental period compared to those from the other plant materials. The residual C Of all the plant materials in the two soils under upland conditions mineralized st rates corresponding to half-lives between 4.4-6.6 years,while the corresponding figures for thine under submerged conditions were between 6.5-13.1 years. Minerallization of residual organic N followed the same pattern as residual C. Compared to residual C, however, the mineralization rates of residual organic N in most cases were significantly lower and the percentages of added N regained in sons were higher. More N from plat materials was retained in the yellow-brown soil than in the red soil, but no consistent differences in the amounts of C from plant materials and in the mineralization rates of both residual C and residual organic N between the two soils could be found.
基金Sponsored by the National Natural Science Foundation of China (Grant No.50675052)
文摘In order to improve the effectiveness of traditional time domain identification methods in identifying damping ratios, a new damping ratio identification method based on pattern search is proposed by fluctuating the reliable natural frequency obtained through traditional time domain identification methods by about 10% to build the boundary conditions, using all the initial identification results to establish the free decay response of the system, and using the pattern search method to correct the initial identification results with the residual sum of squares between the free decay response and the actually measured free-decay signal as the objective function. The proposed method deals with the actually measured free-decay signal with curve fitting and avoids enlarging the identified error caused by intermediate conversion, so it can effectively improve the identified accuracy of damping ratios. Simulations for a room-sized vibration isolation foundation show that the relative errors of analyzed three damping ratios are down to 1.05%, 1.51% and 3.7% by the proposed method from 8.42%, 5.85% and 8.5% by STD method when the noise level is 10%.
