The Tian Qin space-borne gravitational wave detector will orbit at an altitude of1.0×10^(5)km with an arm length of 1.7×10^(5)km,structured in an equilateral triangular satellite formation.The Tian Qin proje...The Tian Qin space-borne gravitational wave detector will orbit at an altitude of1.0×10^(5)km with an arm length of 1.7×10^(5)km,structured in an equilateral triangular satellite formation.The Tian Qin project delineates detailed requirements for orbit determination during both the launch phase and subsequent scientific experimentation.This paper pioneers the investigation of Precise Orbit Determination(POD)for Tian Qin utilizing the third generation of Bei Dou global navigation satellite system(BDS-3)Inter-Satellite Link(ISL)through simulation.By analyzing the visibility,the feasibility of using BDS-3 ISLs for Tian Qin POD is explored.Furthermore,a refined Solar Radiation Pressure(SRP)model is developed,and the POD accuracy of Tian Qin is assessed,considering factors such as arc length,ranging intervals,and error sources.The results indicate the following:(A)Visibility between Tian Qin and BDS-3 satellites is intermittent,with an average of 10.6 BDS-3 satellites visible to Tian Qin,and the average Root Mean Square(RMS)-value of Position Dilution of Precision(PDOP)for Tian Qin is 48.13.(B)POD accuracy improves with shorter ranging intervals.(C)The error in ephemeris is the dominant factor affecting the POD accuracy.(D)The establishment of three links between Tian Qin and the BDS-3 satellites satisfies the POD requirements of Tian Qin.With a ranging interval of 600 s and over a 7-day arc,the average three-Dimensional(3D)position accuracy of the three Tian Qin satellites is 1.35 m,while the 3D velocity accuracy is 0.08 mm/s.展开更多
In this study,enhanced kinetics of methane hydrate formation in the sodium dodecyl sulfate(SDS)solution with different concentrations of suspended graphite nanoparticles(GNPs)were investigated at 6.1-9.0 MPa and 274.1...In this study,enhanced kinetics of methane hydrate formation in the sodium dodecyl sulfate(SDS)solution with different concentrations of suspended graphite nanoparticles(GNPs)were investigated at 6.1-9.0 MPa and 274.15 K.The GNPs with rough surfaces and excellent thermal conductivity not only provided a considerable number of microsites for hydrate nucleation but also facilitated the fast hydrate heat transfer in the suspension system.At a relatively low pressure of 6.1 MPa,the suspension with 0.4 wt%of GNPs exhibited the minimum induction time of 22 min and maximum methane uptake of 126.1 cm3·cm-3.However,the methane storage performances of the suspensions with higher and lower concentrations of GNPs were not satisfactory.At the applied pressure,the temperature increase arising from the hydrate heat in the suspension system with the optimized concentration(0.4 wt%)of GNPs was more significant than that in the traditional SDS solution.Furthermore,compared with those of the system without GNPs,enhanced hydration rate and storage capacity were achieved in the suspensions with GNPs,and the storage capacities were increased by 3.9%-17.0%.The promotion effect of GNPs on gas hydrate formation at low pressure is much more obvious than that at high pressure.展开更多
基金co-supported by the Guangdong Major Project of Basic and Applied Basic Research,China(No.2019B030302001)the Guangdong Basic and Applied Basic Research Foundation,China(No.2022A1515110236)the Fundamental Research Funds for the Central Universities,Sun Yat-Sen University,China(No.23xkjc001)。
文摘The Tian Qin space-borne gravitational wave detector will orbit at an altitude of1.0×10^(5)km with an arm length of 1.7×10^(5)km,structured in an equilateral triangular satellite formation.The Tian Qin project delineates detailed requirements for orbit determination during both the launch phase and subsequent scientific experimentation.This paper pioneers the investigation of Precise Orbit Determination(POD)for Tian Qin utilizing the third generation of Bei Dou global navigation satellite system(BDS-3)Inter-Satellite Link(ISL)through simulation.By analyzing the visibility,the feasibility of using BDS-3 ISLs for Tian Qin POD is explored.Furthermore,a refined Solar Radiation Pressure(SRP)model is developed,and the POD accuracy of Tian Qin is assessed,considering factors such as arc length,ranging intervals,and error sources.The results indicate the following:(A)Visibility between Tian Qin and BDS-3 satellites is intermittent,with an average of 10.6 BDS-3 satellites visible to Tian Qin,and the average Root Mean Square(RMS)-value of Position Dilution of Precision(PDOP)for Tian Qin is 48.13.(B)POD accuracy improves with shorter ranging intervals.(C)The error in ephemeris is the dominant factor affecting the POD accuracy.(D)The establishment of three links between Tian Qin and the BDS-3 satellites satisfies the POD requirements of Tian Qin.With a ranging interval of 600 s and over a 7-day arc,the average three-Dimensional(3D)position accuracy of the three Tian Qin satellites is 1.35 m,while the 3D velocity accuracy is 0.08 mm/s.
基金supported by the National Natural Science Foundation of China(grant numbers 51606125,51802190,21978171,51876130,51674240)the Innovation Program of Shanghai Municipal Education Commission(grant number 13ZZ117)。
文摘In this study,enhanced kinetics of methane hydrate formation in the sodium dodecyl sulfate(SDS)solution with different concentrations of suspended graphite nanoparticles(GNPs)were investigated at 6.1-9.0 MPa and 274.15 K.The GNPs with rough surfaces and excellent thermal conductivity not only provided a considerable number of microsites for hydrate nucleation but also facilitated the fast hydrate heat transfer in the suspension system.At a relatively low pressure of 6.1 MPa,the suspension with 0.4 wt%of GNPs exhibited the minimum induction time of 22 min and maximum methane uptake of 126.1 cm3·cm-3.However,the methane storage performances of the suspensions with higher and lower concentrations of GNPs were not satisfactory.At the applied pressure,the temperature increase arising from the hydrate heat in the suspension system with the optimized concentration(0.4 wt%)of GNPs was more significant than that in the traditional SDS solution.Furthermore,compared with those of the system without GNPs,enhanced hydration rate and storage capacity were achieved in the suspensions with GNPs,and the storage capacities were increased by 3.9%-17.0%.The promotion effect of GNPs on gas hydrate formation at low pressure is much more obvious than that at high pressure.
