Angles-only relative orbit determination for space non-cooperative targets based on passive sensor is subject to weakly observable problem of the relative state between two spacecraft. Previously, the evidence for ang...Angles-only relative orbit determination for space non-cooperative targets based on passive sensor is subject to weakly observable problem of the relative state between two spacecraft. Previously, the evidence for angles-only observability was found by using cylindrical dynamics, however, the solution of orbit determination is still not provided. This study develops a relative orbit determination algorithm with the cylindrical dynamics based on differential evolution. Firstly, the relative motion dynamics and line-of-sight measurement model for nearcircular orbit are established in cylindrical coordinate system.Secondly, the observability is qualitatively analyzed by using the dynamics and measurement model where the unobservable geometry is found. Then, the angles-only relative orbit determination problem is modeled into an optimal searching frame and an improved differential evolution algorithm is introduced to solve the problem. Finally, the proposed algorithm is verified and tested by a set of numerical simulations in the context of highEarth and low-Earth cases. The results show that initial relative orbit determination(IROD) solution with an appropriate accuracy in a relative short span is achieved, which can be used to initialize the navigation filter.展开更多
This work introduces a novel method for measuring thin film thickness,employing a multi-wavelength method that significantly reduces the need for broad-spectrum data.Unlike traditional techniques that require sev⁃eral...This work introduces a novel method for measuring thin film thickness,employing a multi-wavelength method that significantly reduces the need for broad-spectrum data.Unlike traditional techniques that require sev⁃eral hundred spectral data points,the multi-wavelength method achieves precise thickness measurements with data from only 10 wavelengths.This innovation not only simplifies the process of spectral measurement analysis but also enables accurate real-time thickness measurement on industrial coating production lines.The method effectively reconstructs and fits the visible spectrum(400-800 nm)using a minimal amount of data,while maintaining measurement error within 7.1%.This advancement lays the foundation for more practical and efficient thin film thickness determination techniques in various industrial applications.展开更多
A new method was developed for determination of 407 pesticide residues in complex matrix by using LC-MS with triple quadrupole(QQQ).Comparing with regular method,the method has high sensitivity and repeativity,and was...A new method was developed for determination of 407 pesticide residues in complex matrix by using LC-MS with triple quadrupole(QQQ).Comparing with regular method,the method has high sensitivity and repeativity,and was applied for the determination of peticide in real sample with satisfactory results.展开更多
Various trace elements, especially potential toxic trace elements such as As, Cd, Cr, Cu, Hg, Pb, Ni, Se, Tl, Zn, would be concentrated in processing of coal. Determination of these elements in coal is very important ...Various trace elements, especially potential toxic trace elements such as As, Cd, Cr, Cu, Hg, Pb, Ni, Se, Tl, Zn, would be concentrated in processing of coal. Determination of these elements in coal is very important for identification of coal quality. A method is developed for determination of 49 trace elements in coal by high resolution inductively coupled plasma mass spectrometry (HR-ICPMS). Microwave acid digestion and low-temperature airproof acid digestion for sample preparation were investigated. It is shown that the low-temperature airproof acid digestion method is of lower blank, and more suitalbe for the coal sample preparation. The on-line internal standard (Rh) sample introduction is applied to compensate matrix effects in measurement by ICPMS. The method gives low detection limits (0.002-1.60 μg/g) and better relative standard deviations (0.60%-4.78%) for the determined 49 elements in coal.展开更多
A GC-MS method was established for determination of 10 pyrethroids in apple juice concentrate.The sample was extracted by acetone and hexane,and the 10 pyrethroids were separated on a capillary column(DB-5,30 m×2...A GC-MS method was established for determination of 10 pyrethroids in apple juice concentrate.The sample was extracted by acetone and hexane,and the 10 pyrethroids were separated on a capillary column(DB-5,30 m×250 μm×0.25 μm) and determined by GC-MSD.The recoveries of pyrethroids were range of 84%-96% with the detection limits of 3-46 μg/kg.The relative standard deviations were range of 0.68%-5.11%.展开更多
A direct determination method for the atrazine residue on the vegetable was developed by using desorption electrospray ionization mass spectrometry (DESI MS) without any sample pretreatment.Acetonitrile-water (1:1,v/v...A direct determination method for the atrazine residue on the vegetable was developed by using desorption electrospray ionization mass spectrometry (DESI MS) without any sample pretreatment.Acetonitrile-water (1:1,v/v),which contained 0.1% formic acid,was used as the spray solvent.The working conditions,such as ESI gas inlet pressure,ESI flow rate,ESI spray voltage,spray-to-sample distance,spray-to-cone-hole distance and the collision induced dissociation (CID) voltage for MS/MS,were optimized for both DESI and esquires 6 000 mass spectrometer.The linear range of atrazine on cabbage leaves was 25.25-2 525 pg/mm2,the R2 was 0.991 6,and the relative standard deviations were between 3.37% and 26.17%.The LOD of atrazine calculated by S/N=3 was 2.50 pg/mm2.展开更多
A high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICPMS) was combined, and the chromatography conditions were optimized. The stability and homogeneity of a trimethyllead refer...A high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICPMS) was combined, and the chromatography conditions were optimized. The stability and homogeneity of a trimethyllead reference material were determined using this method.展开更多
In human subjects,morphine is extensively metabolized to form(M3G)and morphine-6-glucuronide(M6G).This article established a sensitive LC-MS/MS method that allows the quantification of morphine and its glucuronide met...In human subjects,morphine is extensively metabolized to form(M3G)and morphine-6-glucuronide(M6G).This article established a sensitive LC-MS/MS method that allows the quantification of morphine and its glucuronide metabolites.展开更多
A method for simultaneous determination of oxytetracycline,tetracycline,chlortetracycline in animal tissue was successfully established by HPLC-ESI MS/MS.The tetracycline antibiotics in animal tissue were extracted by...A method for simultaneous determination of oxytetracycline,tetracycline,chlortetracycline in animal tissue was successfully established by HPLC-ESI MS/MS.The tetracycline antibiotics in animal tissue were extracted by liquid-solid extraction and cleaned up by SPE.The mass spectrometer was operated in the positive-ion mode using selected reaction monitoring(SRM).The results showed that three tetracycline antibiotics were well separated under the optimal conditions.The detection limits of oxytetracycline,tetracycline and chlortetracycline were 0.16 ng/g,0.1 ng/g and 0.1 ng/g,respectively.The spiked recoveries were range of 84%-94% and the relative standard deviations were 2.4%-2.9%.展开更多
A method for the simultaneous determination of β2-agonists residues was developed by LC-MS/MS.The results indicated that the calibration curves showed good linear range from 0.1 g/L to 10 g/L for 11 β2-agonists.The ...A method for the simultaneous determination of β2-agonists residues was developed by LC-MS/MS.The results indicated that the calibration curves showed good linear range from 0.1 g/L to 10 g/L for 11 β2-agonists.The spiked recoveries were between 79% and 110%.The method was rapid,accurate,and was suitable for the determination of β2-agonists in animal food.展开更多
The autonomous "celestial navigation scheme" for deep space probe departing from the earth and the autonomous "optical navigation scheme" for encountering object celestial body are presented. Then,...The autonomous "celestial navigation scheme" for deep space probe departing from the earth and the autonomous "optical navigation scheme" for encountering object celestial body are presented. Then, aiming at the conditions that large initial estimation errors and non-Gaussian distribution of state or measurement errors may exist in orbit determination process of the two phases, UPF (unscented particle filter) is introduced into the navigation schemes. By tackling nonlinear and non-Gaussian problems, UPF overcomes the accuracy influence brought by the traditional EKF (extended Kalman filter), UKF (unscented Kalman filter), and PF (particle filter) schemes in approximate treatment to nonlinear and non-Gaussian state model and measurement model. The numerical simulations demonstrate the feasibility and higher accuracy of the UPF navigation scheme.展开更多
Based on the field destructive test of six rock-socketed piles with shallow overburden,three prediction models are used to quantitatively analyze and predict the intact load−displacement curve.The predicted values of ...Based on the field destructive test of six rock-socketed piles with shallow overburden,three prediction models are used to quantitatively analyze and predict the intact load−displacement curve.The predicted values of ultimate uplift capacity were further determined by four methods(displacement controlling method(DCM),reduction coefficient method(RCM),maximum curvature method(MCM),and critical stiffness method(CSM))and compared with the measured value.Through the analysis of the relationship between the change rate of pullout stiffness and displacement,a method used to determine the ultimate uplift capacity via non-intact load−displacement curve was proposed.The results show that the predicted value determined by DCM is more conservative,while the predicted value determined by MCM is larger than the measured value.This suggests that RCM and CSM in engineering applications can be preferentially applied.Moreover,the development law of the change rate of pullout stiffness with displacement agrees well with the attenuation form of power function.The theoretical predicted results of ultimate uplift capacity based on the change rate of pullout stiffness will not be affected by the integrity of the curve.The method is simple and applicable for the piles that are not loaded to failure state,and thus provides new insights into ultimate uplift capacity determination of test piles.展开更多
In view of the problem that the current single-antenna GPS attitude determination system can only determine the body attitude when the sideslip angle is zero and the multiantenna GPS/SINS integrated navigation system ...In view of the problem that the current single-antenna GPS attitude determination system can only determine the body attitude when the sideslip angle is zero and the multiantenna GPS/SINS integrated navigation system is of large volume, high cost, and complex structure, this approach is presented to determine the attitude based on vector space with single-antenna GPS and accelerometers in the micro inertial measurement unit （MIMU）. It can provide real-time and accurate attitude information. Subsequently, the single-antenna GPS/SINS integrated navigation system is designed based on the combination of position, velocity, and attitude. Finally the semi- physical simulations of single-antenna GPS attitude determination system and single-antenna GPS/SINS integrated navigation system are carried out. The simulation results, based on measured data, show that the single-antenna GPS/SINS system can provide more accurate navigation information compared to the GPS/SINS system, based on the combination of position and velocity. Furthermore, the single-antenna GPS/SINS system is characteristic of lower cost and simpler structure. It provides the basis for the application of a single-antenna GPS/SINS integrated navigation system in a micro aerial vehicle （MAV）.展开更多
Reagents are optimized for the simultaneous determination of trace amounts of Cu^(2+), Cd^(2+) and Co^(2+) in zinc sulfate solution, which contains an extremely large excess of Zn^(2+). First, the reagents and their d...Reagents are optimized for the simultaneous determination of trace amounts of Cu^(2+), Cd^(2+) and Co^(2+) in zinc sulfate solution, which contains an extremely large excess of Zn^(2+). First, the reagents and their doses for the experiment are selected according to the characteristics of the zinc sulfate solution. Then, the reagent doses are optimized by analyzing the influence of reagent dose on the polarographic parameters(i.e. half-wave potential E_(1/2) and limiting diffusion current I_p). Finally, the optimization results are verified by simultaneously determining trace amounts of Cu^(2+), Cd^(2+) and Co^(2+) in the presence of an extremely large excess of Zn^(2+). The determination results indicate that the optimized reagents exhibit wide linearity, low detection limits, high accuracy and good precision for the simultaneous determination of trace amounts of Cu^(2+), Cd^(2+) and Co^(2+) in the presence of an extremely large excess of Zn^(2+).展开更多
Dual-frequency multi-constellation(DFMC) satellitebased augmentation system(SBAS) does not broadcast fast correction, which is important in reducing range error in L1-only SBAS.Meanwhile, the integrity bound of a sate...Dual-frequency multi-constellation(DFMC) satellitebased augmentation system(SBAS) does not broadcast fast correction, which is important in reducing range error in L1-only SBAS.Meanwhile, the integrity bound of a satellite at low elevation is so loose that the service availability is decreased near the boundary of the service area. Therefore, the computation of satellite clockephemeris(SCE) augmentation parameters needs improvement.We propose a method introducing SCE prediction to eliminate most of the SCE error resulting from global navigation satellite system GNSS broadcast message. Compared with the signal-inspace(SIS) after applying augmentation parameters broadcast by the wide area augmentation system(WAAS), SIS accuracy after applying augmentation parameters computed by the proposed algorithm is improved and SIS integrity is ensured. With global positioning system(GPS) only, the availability of category-I(CAT-I)with a vertical alert level of 15 m in continental United States is about 90%, while the availability in the other part of the WAAS service area is markedly improved. With measurements made by the stations from the crustal movement observation network of China,users in some part of China can obtain CAT-I(vertical alert limit is 15 m) service with GPS and global navigation satellite system(GLONASS).展开更多
基金supported by the National Natural Science Foundation of China (12272168)the Foundation of Science and Technology on Space Intelligent Control Laboratory (HTKJ2023KL502015)。
文摘Angles-only relative orbit determination for space non-cooperative targets based on passive sensor is subject to weakly observable problem of the relative state between two spacecraft. Previously, the evidence for angles-only observability was found by using cylindrical dynamics, however, the solution of orbit determination is still not provided. This study develops a relative orbit determination algorithm with the cylindrical dynamics based on differential evolution. Firstly, the relative motion dynamics and line-of-sight measurement model for nearcircular orbit are established in cylindrical coordinate system.Secondly, the observability is qualitatively analyzed by using the dynamics and measurement model where the unobservable geometry is found. Then, the angles-only relative orbit determination problem is modeled into an optimal searching frame and an improved differential evolution algorithm is introduced to solve the problem. Finally, the proposed algorithm is verified and tested by a set of numerical simulations in the context of highEarth and low-Earth cases. The results show that initial relative orbit determination(IROD) solution with an appropriate accuracy in a relative short span is achieved, which can be used to initialize the navigation filter.
基金Supported by National Key R&D Program of China(2021YFA0715500)National Natural Science Foundation of China(NSFC)(12227901)+2 种基金Strategic Priority Research Program(B)of the Chinese Academy of Sciences(XDB0580000)Shanghai Municipal Science and Technology Major Project(2019SHZDZX01)Chinese Academy of Sciences President's International Fellowship Initiative(2021PT0007).
文摘This work introduces a novel method for measuring thin film thickness,employing a multi-wavelength method that significantly reduces the need for broad-spectrum data.Unlike traditional techniques that require sev⁃eral hundred spectral data points,the multi-wavelength method achieves precise thickness measurements with data from only 10 wavelengths.This innovation not only simplifies the process of spectral measurement analysis but also enables accurate real-time thickness measurement on industrial coating production lines.The method effectively reconstructs and fits the visible spectrum(400-800 nm)using a minimal amount of data,while maintaining measurement error within 7.1%.This advancement lays the foundation for more practical and efficient thin film thickness determination techniques in various industrial applications.
文摘A new method was developed for determination of 407 pesticide residues in complex matrix by using LC-MS with triple quadrupole(QQQ).Comparing with regular method,the method has high sensitivity and repeativity,and was applied for the determination of peticide in real sample with satisfactory results.
文摘Various trace elements, especially potential toxic trace elements such as As, Cd, Cr, Cu, Hg, Pb, Ni, Se, Tl, Zn, would be concentrated in processing of coal. Determination of these elements in coal is very important for identification of coal quality. A method is developed for determination of 49 trace elements in coal by high resolution inductively coupled plasma mass spectrometry (HR-ICPMS). Microwave acid digestion and low-temperature airproof acid digestion for sample preparation were investigated. It is shown that the low-temperature airproof acid digestion method is of lower blank, and more suitalbe for the coal sample preparation. The on-line internal standard (Rh) sample introduction is applied to compensate matrix effects in measurement by ICPMS. The method gives low detection limits (0.002-1.60 μg/g) and better relative standard deviations (0.60%-4.78%) for the determined 49 elements in coal.
文摘A GC-MS method was established for determination of 10 pyrethroids in apple juice concentrate.The sample was extracted by acetone and hexane,and the 10 pyrethroids were separated on a capillary column(DB-5,30 m×250 μm×0.25 μm) and determined by GC-MSD.The recoveries of pyrethroids were range of 84%-96% with the detection limits of 3-46 μg/kg.The relative standard deviations were range of 0.68%-5.11%.
文摘A direct determination method for the atrazine residue on the vegetable was developed by using desorption electrospray ionization mass spectrometry (DESI MS) without any sample pretreatment.Acetonitrile-water (1:1,v/v),which contained 0.1% formic acid,was used as the spray solvent.The working conditions,such as ESI gas inlet pressure,ESI flow rate,ESI spray voltage,spray-to-sample distance,spray-to-cone-hole distance and the collision induced dissociation (CID) voltage for MS/MS,were optimized for both DESI and esquires 6 000 mass spectrometer.The linear range of atrazine on cabbage leaves was 25.25-2 525 pg/mm2,the R2 was 0.991 6,and the relative standard deviations were between 3.37% and 26.17%.The LOD of atrazine calculated by S/N=3 was 2.50 pg/mm2.
文摘A high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICPMS) was combined, and the chromatography conditions were optimized. The stability and homogeneity of a trimethyllead reference material were determined using this method.
文摘In human subjects,morphine is extensively metabolized to form(M3G)and morphine-6-glucuronide(M6G).This article established a sensitive LC-MS/MS method that allows the quantification of morphine and its glucuronide metabolites.
文摘A method for simultaneous determination of oxytetracycline,tetracycline,chlortetracycline in animal tissue was successfully established by HPLC-ESI MS/MS.The tetracycline antibiotics in animal tissue were extracted by liquid-solid extraction and cleaned up by SPE.The mass spectrometer was operated in the positive-ion mode using selected reaction monitoring(SRM).The results showed that three tetracycline antibiotics were well separated under the optimal conditions.The detection limits of oxytetracycline,tetracycline and chlortetracycline were 0.16 ng/g,0.1 ng/g and 0.1 ng/g,respectively.The spiked recoveries were range of 84%-94% and the relative standard deviations were 2.4%-2.9%.
文摘A method for the simultaneous determination of β2-agonists residues was developed by LC-MS/MS.The results indicated that the calibration curves showed good linear range from 0.1 g/L to 10 g/L for 11 β2-agonists.The spiked recoveries were between 79% and 110%.The method was rapid,accurate,and was suitable for the determination of β2-agonists in animal food.
基金the National "863" High Technology Development Project of China (2005AA735080).
文摘The autonomous "celestial navigation scheme" for deep space probe departing from the earth and the autonomous "optical navigation scheme" for encountering object celestial body are presented. Then, aiming at the conditions that large initial estimation errors and non-Gaussian distribution of state or measurement errors may exist in orbit determination process of the two phases, UPF (unscented particle filter) is introduced into the navigation schemes. By tackling nonlinear and non-Gaussian problems, UPF overcomes the accuracy influence brought by the traditional EKF (extended Kalman filter), UKF (unscented Kalman filter), and PF (particle filter) schemes in approximate treatment to nonlinear and non-Gaussian state model and measurement model. The numerical simulations demonstrate the feasibility and higher accuracy of the UPF navigation scheme.
基金Project(2016YFC0802203)supported by the National Key R&D Program of ChinaProject(2013G001-A-2)supported by the Science and Technology Research and Development Program of China Railway CorporationProject(SKLGDUEK2011)supported by the State Key Laboratory for GeoMechanics and Deep Underground Engineering,China University of Mining&Technology。
文摘Based on the field destructive test of six rock-socketed piles with shallow overburden,three prediction models are used to quantitatively analyze and predict the intact load−displacement curve.The predicted values of ultimate uplift capacity were further determined by four methods(displacement controlling method(DCM),reduction coefficient method(RCM),maximum curvature method(MCM),and critical stiffness method(CSM))and compared with the measured value.Through the analysis of the relationship between the change rate of pullout stiffness and displacement,a method used to determine the ultimate uplift capacity via non-intact load−displacement curve was proposed.The results show that the predicted value determined by DCM is more conservative,while the predicted value determined by MCM is larger than the measured value.This suggests that RCM and CSM in engineering applications can be preferentially applied.Moreover,the development law of the change rate of pullout stiffness with displacement agrees well with the attenuation form of power function.The theoretical predicted results of ultimate uplift capacity based on the change rate of pullout stiffness will not be affected by the integrity of the curve.The method is simple and applicable for the piles that are not loaded to failure state,and thus provides new insights into ultimate uplift capacity determination of test piles.
基金the Astronautic Technology Foundation (HTZC0405)
文摘In view of the problem that the current single-antenna GPS attitude determination system can only determine the body attitude when the sideslip angle is zero and the multiantenna GPS/SINS integrated navigation system is of large volume, high cost, and complex structure, this approach is presented to determine the attitude based on vector space with single-antenna GPS and accelerometers in the micro inertial measurement unit （MIMU）. It can provide real-time and accurate attitude information. Subsequently, the single-antenna GPS/SINS integrated navigation system is designed based on the combination of position, velocity, and attitude. Finally the semi- physical simulations of single-antenna GPS attitude determination system and single-antenna GPS/SINS integrated navigation system are carried out. The simulation results, based on measured data, show that the single-antenna GPS/SINS system can provide more accurate navigation information compared to the GPS/SINS system, based on the combination of position and velocity. Furthermore, the single-antenna GPS/SINS system is characteristic of lower cost and simpler structure. It provides the basis for the application of a single-antenna GPS/SINS integrated navigation system in a micro aerial vehicle （MAV）.
基金Projects(61533021,61321003,61273185)supported by the National Natural Science Foundation of ChinaProject(2015CX007)supported by the Innovation-driven Plan in Central South University,ChinaProject(13JJ8003)supported by the Joint Fund of Hunan Provincial Natural Science Foundation of China
文摘Reagents are optimized for the simultaneous determination of trace amounts of Cu^(2+), Cd^(2+) and Co^(2+) in zinc sulfate solution, which contains an extremely large excess of Zn^(2+). First, the reagents and their doses for the experiment are selected according to the characteristics of the zinc sulfate solution. Then, the reagent doses are optimized by analyzing the influence of reagent dose on the polarographic parameters(i.e. half-wave potential E_(1/2) and limiting diffusion current I_p). Finally, the optimization results are verified by simultaneously determining trace amounts of Cu^(2+), Cd^(2+) and Co^(2+) in the presence of an extremely large excess of Zn^(2+). The determination results indicate that the optimized reagents exhibit wide linearity, low detection limits, high accuracy and good precision for the simultaneous determination of trace amounts of Cu^(2+), Cd^(2+) and Co^(2+) in the presence of an extremely large excess of Zn^(2+).
文摘Dual-frequency multi-constellation(DFMC) satellitebased augmentation system(SBAS) does not broadcast fast correction, which is important in reducing range error in L1-only SBAS.Meanwhile, the integrity bound of a satellite at low elevation is so loose that the service availability is decreased near the boundary of the service area. Therefore, the computation of satellite clockephemeris(SCE) augmentation parameters needs improvement.We propose a method introducing SCE prediction to eliminate most of the SCE error resulting from global navigation satellite system GNSS broadcast message. Compared with the signal-inspace(SIS) after applying augmentation parameters broadcast by the wide area augmentation system(WAAS), SIS accuracy after applying augmentation parameters computed by the proposed algorithm is improved and SIS integrity is ensured. With global positioning system(GPS) only, the availability of category-I(CAT-I)with a vertical alert level of 15 m in continental United States is about 90%, while the availability in the other part of the WAAS service area is markedly improved. With measurements made by the stations from the crustal movement observation network of China,users in some part of China can obtain CAT-I(vertical alert limit is 15 m) service with GPS and global navigation satellite system(GLONASS).
