In this study, a simple, reliable and accurate method for the simultaneous separation and determination of naringin, hesperidin, neohesperidin, baicalin, wogonoside, baicalein, wogonin, emodin and chrysophanol in ‘Da...In this study, a simple, reliable and accurate method for the simultaneous separation and determination of naringin, hesperidin, neohesperidin, baicalin, wogonoside, baicalein, wogonin, emodin and chrysophanol in ‘Da-Chai-Hu-Tang’ was developed by reverse-phase high-performance liquid chromatography (RP-HPLC). The chromatographic separation was performed on an Agilent ZORBAX C18 column (250 mm × 4.6 mm i.d., 5.0 μm), and the mobile phase composed of methanol and water containing 1% (v/v) acetic acid was used to elute the targets in a gradient elution mode. The flow rate and detection wavelength were set at 0.8 ml/min and 280 nm, respectively. All calibration curves of the nine components expressed good linearities (r2≥0.9992) within the tested ranges. The RSD values demonstrated the intra- and inter-day precisions were less than 2.89%, and the recoveries of the investigated compounds were between 96.22% and 105.28%. The proposed method is simple, precise, specific, sensitive, and successfully applied to determine the nine marker compounds in ‘Da-Chai-Hu-Tang’ for quality control.展开更多
An algorithm for robust initial orbit determination (IOD) under perturbed orbital dynamics is presented. By leveraging map inversion techniques defined in the algebra of Taylor polynomials, this tool returns a highly ...An algorithm for robust initial orbit determination (IOD) under perturbed orbital dynamics is presented. By leveraging map inversion techniques defined in the algebra of Taylor polynomials, this tool returns a highly accurate solution to the IOD problem and estimates a range centered on the aforementioned solution in which the true orbit should lie. To meet the specified accuracy requirements, automatic domain splitting is used to wrap the IOD routines and ensure that the local truncation error, introduced by a polynomial representation of the state estimate, remains below a predefined threshold. The algorithm is presented for three types of ground-based sensors, namely range radars, Doppler-only radars, and optical telescopes, by considering their different constraints in terms of available measurements and sensor noise. Finally, the improvement in performance with respect to a Keplerian-based IOD solution is demonstrated using large-scale numerical simulations over a subset of tracked objects in low Earth orbit.展开更多
This study examined regional differences in ecosystem services for the Da Hinggan Mountains(DHM),China.A correction index was constructed based on ten-year average net primary productivity(NPP)data.A new equivalent fa...This study examined regional differences in ecosystem services for the Da Hinggan Mountains(DHM),China.A correction index was constructed based on ten-year average net primary productivity(NPP)data.A new equivalent factor table that was suitable for the assessment of wetlands in the DHM was formed by using the expert weight determination method(EWDM).An evaluation model was established for evaluating the ecosystem service value(ESV)of wetlands in the DHM.The results show that in 2020,the total ESV of wetlands reached 93361×10^(6) USD,with the forest swamp and marsh ecosystems contributing the most.From the perspective of value composition,regulating services and supporting services are the main service functions of wetlands in the DHM.From 2010 to2020,ESV provided by wetlands increased by 4337×10^(6) USD/yr in the DHM.The value of forest swamp and peatland ecosystems increased by 18.6%and 12.7%,respectively,whereas the value of swamp,shrub swamp,and marsh decreased.The research results are of significance for contributing to local government performance evaluation and determining financial compensation for the provision of wetland ecosystem services.展开更多
文摘In this study, a simple, reliable and accurate method for the simultaneous separation and determination of naringin, hesperidin, neohesperidin, baicalin, wogonoside, baicalein, wogonin, emodin and chrysophanol in ‘Da-Chai-Hu-Tang’ was developed by reverse-phase high-performance liquid chromatography (RP-HPLC). The chromatographic separation was performed on an Agilent ZORBAX C18 column (250 mm × 4.6 mm i.d., 5.0 μm), and the mobile phase composed of methanol and water containing 1% (v/v) acetic acid was used to elute the targets in a gradient elution mode. The flow rate and detection wavelength were set at 0.8 ml/min and 280 nm, respectively. All calibration curves of the nine components expressed good linearities (r2≥0.9992) within the tested ranges. The RSD values demonstrated the intra- and inter-day precisions were less than 2.89%, and the recoveries of the investigated compounds were between 96.22% and 105.28%. The proposed method is simple, precise, specific, sensitive, and successfully applied to determine the nine marker compounds in ‘Da-Chai-Hu-Tang’ for quality control.
基金co-funded by the Centre National d’Études Spatiales(CNES)through A.FossàPh.D.program and made use of the CNES orbital propagation tools,including the PACE library.
文摘An algorithm for robust initial orbit determination (IOD) under perturbed orbital dynamics is presented. By leveraging map inversion techniques defined in the algebra of Taylor polynomials, this tool returns a highly accurate solution to the IOD problem and estimates a range centered on the aforementioned solution in which the true orbit should lie. To meet the specified accuracy requirements, automatic domain splitting is used to wrap the IOD routines and ensure that the local truncation error, introduced by a polynomial representation of the state estimate, remains below a predefined threshold. The algorithm is presented for three types of ground-based sensors, namely range radars, Doppler-only radars, and optical telescopes, by considering their different constraints in terms of available measurements and sensor noise. Finally, the improvement in performance with respect to a Keplerian-based IOD solution is demonstrated using large-scale numerical simulations over a subset of tracked objects in low Earth orbit.
基金Under the auspices of the National Natural Science Foundation of China(No.U19A2042,U20A2083,42001112)。
文摘This study examined regional differences in ecosystem services for the Da Hinggan Mountains(DHM),China.A correction index was constructed based on ten-year average net primary productivity(NPP)data.A new equivalent factor table that was suitable for the assessment of wetlands in the DHM was formed by using the expert weight determination method(EWDM).An evaluation model was established for evaluating the ecosystem service value(ESV)of wetlands in the DHM.The results show that in 2020,the total ESV of wetlands reached 93361×10^(6) USD,with the forest swamp and marsh ecosystems contributing the most.From the perspective of value composition,regulating services and supporting services are the main service functions of wetlands in the DHM.From 2010 to2020,ESV provided by wetlands increased by 4337×10^(6) USD/yr in the DHM.The value of forest swamp and peatland ecosystems increased by 18.6%and 12.7%,respectively,whereas the value of swamp,shrub swamp,and marsh decreased.The research results are of significance for contributing to local government performance evaluation and determining financial compensation for the provision of wetland ecosystem services.
