Large-scale deformation can not be detected by traditional D-InSAR technique because of the limit of its detectable deformation gradient,we propose a method that combines SAR data with point cloud data obtained by 3D ...Large-scale deformation can not be detected by traditional D-InSAR technique because of the limit of its detectable deformation gradient,we propose a method that combines SAR data with point cloud data obtained by 3D laser scanning to improve the gradient of deformation detection.The proposed method takes advantage of high-density of 3D laser scanning point cloud data and its high precision of point positioning after 3D modeling.The specifc process can be described as follows:frst,large-scale deformation points in the interferogram are masked out based on interferometric coherence;second,the interferogram with holes is unwrapped to obtain a deformation map with holes,and last,the holes in the deformation map are flled with point cloud data using inverse distance weighting algorithm,which will achieve seamless connection of monitoring region.We took the embankment dam above working face of a certain mining area in Shandong province as an example to study large-scale deformation in mining area using the proposed method.The results show that the maximum absolute error is 64 mm,relative error of maximum subsidence value is 4.95%,and they are consistent with leveling data of ground observation stations,which confrms the feasibility of this method.The method we presented provides new ways and means for achieving large-scale deformation monitoring by D-InSAR in mining area.展开更多
To maintain the stability of the inter-satellite link for gravitational wave detection,an intelligent learning monitoring and fast warning method of the inter-satellite link control system failure is proposed.Differen...To maintain the stability of the inter-satellite link for gravitational wave detection,an intelligent learning monitoring and fast warning method of the inter-satellite link control system failure is proposed.Different from the traditional fault diagnosis optimization algorithms,the fault intelligent learning method pro-posed in this paper is able to quickly identify the faults of inter-satellite link control system despite the existence of strong cou-pling nonlinearity.By constructing a two-layer learning network,the method enables efficient joint diagnosis of fault areas and fault parameters.The simulation results show that the average identification time of the system fault area and fault parameters is 0.27 s,and the fault diagnosis efficiency is improved by 99.8%compared with the traditional algorithm.展开更多
Through sampling and analyzing of plasma optic signals of 400-600 nm emitted from partial-penetration laser welding processes, how the penetration depth is related to the welding parameter and the plasma optic signal ...Through sampling and analyzing of plasma optic signals of 400-600 nm emitted from partial-penetration laser welding processes, how the penetration depth is related to the welding parameter and the plasma optic signal is studied, Under the experimental conditions, the plasma optic signal has good response to variety of the weld penetration, and the signal's RMS value increases with the penetration in a quadratic curve mode. The inherent relation between the plasma optic signal and the penetration depth is also analyzed. It is also found that, between the two common parameters of laser power and welding speed, laser power has more influence on penetration while welding speed has more influence on weld width. The research results provide theoretic and practical bases for penetration real-time monitoring or predicting in partial-penetration laser welding,展开更多
In this paper,the solubility of 4-nitroimidazole in twelve pure solvents(toluene,benzene,1,4-dioxane,acetonitrile,ethyl acetate,acetone,GBL,ethanol,methanol,n-butanol,DMF and NMP)were determined by using the laser mon...In this paper,the solubility of 4-nitroimidazole in twelve pure solvents(toluene,benzene,1,4-dioxane,acetonitrile,ethyl acetate,acetone,GBL,ethanol,methanol,n-butanol,DMF and NMP)were determined by using the laser monitoring system from 278.15 K to 323.15 K under 101.1 k Pa,which are 0.00018–0.00070,0.00021–0.00073,0.00034–0.00092,0.00038–0.00142,0.00047–0.00120,0.00126–0.00303,0.00225–0.00517,0.00310–0.00724,0.00467–0.00982,0.00453–0.01940,0.01947–0.04652,and 0.04670–0.07452,respectively.At constant temperature,the mole fraction solubility of 4-nitroimidazole were increased as the following order:toluene<benzene<1,4-dioxane<(ethyl acetate or acetonitrile)<acetone<GBL<ethanol<(methanol or nbutanol)<DMF<NMP,and the solubility of 4-nitroimidazole in(ethyl acetate,acetonitrile)and(methanol,n-butanol)had an intersection point at 297.55 K and 281.85 K,respectively.The solubility of 4-nitroimidazole could be increased with increasing temperature in twelve pure solvents.The ideal model,modified Apelblat equation,polynomial empirical equation,andλh equation were used to correlate the experimental values.The experimental solubility values were employed to calculate the standard dissolution enthalpy,standard dissolution entropy and Gibbs energy.The dissolution of 4-nitroimidazole could be an endothermic process in twelve pure solvents.The determination and fitting solubility of 4-nitroimidazole have important guiding significance for the purification and crystallization of its preparation process.展开更多
Tunable diode laser absorption spectroscopy (TDLAS) has been widely employed in atmospheric trace gases detection. In the measurement of these trace gases, harmonic detection combined with a multi-pass white cell co...Tunable diode laser absorption spectroscopy (TDLAS) has been widely employed in atmospheric trace gases detection. In the measurement of these trace gases, harmonic detection combined with a multi-pass white cell could remarkably enhance the detection sensitivity. In this paper, a portable TDLAS system built specifically for long time monitoring methane in the atmosphere is introduced. The detection limit is below 100 ppb that is enough for the monitoring of ambient methane, and the long time monitoring results obtained in Beijing are given, which is well coincident with that of the Fourier transform infrared (FTIR) spectroscopy.展开更多
We report a wavelength and power monitoring system based on a scanning MEMS filter as wavelength discriminator and a near threshold-biased Fabry-Perot diode laser as wavelength reference. This system is capable of mon...We report a wavelength and power monitoring system based on a scanning MEMS filter as wavelength discriminator and a near threshold-biased Fabry-Perot diode laser as wavelength reference. This system is capable of monitoring 250 channels of DWDM signal at 25 GHz ITU Grid with an error of less than ±8 pm.展开更多
基金founded by the National Natural Science Foundation of China (No. 41071273)the Doctoral Program Foundation of Institutions of Higher Education of China (No. 20090095110002)+1 种基金the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (No. SZBF2011-6B35)Relevant radar data were provided by the German Aerospace Centre TerraSAR-X Science Plan (LAN1425 and LAN1173)
文摘Large-scale deformation can not be detected by traditional D-InSAR technique because of the limit of its detectable deformation gradient,we propose a method that combines SAR data with point cloud data obtained by 3D laser scanning to improve the gradient of deformation detection.The proposed method takes advantage of high-density of 3D laser scanning point cloud data and its high precision of point positioning after 3D modeling.The specifc process can be described as follows:frst,large-scale deformation points in the interferogram are masked out based on interferometric coherence;second,the interferogram with holes is unwrapped to obtain a deformation map with holes,and last,the holes in the deformation map are flled with point cloud data using inverse distance weighting algorithm,which will achieve seamless connection of monitoring region.We took the embankment dam above working face of a certain mining area in Shandong province as an example to study large-scale deformation in mining area using the proposed method.The results show that the maximum absolute error is 64 mm,relative error of maximum subsidence value is 4.95%,and they are consistent with leveling data of ground observation stations,which confrms the feasibility of this method.The method we presented provides new ways and means for achieving large-scale deformation monitoring by D-InSAR in mining area.
基金This work was supported by the National Key Research and Development Program Topics(2020YFC2200902)the National Natural Science Foundation of China(11872110).
文摘To maintain the stability of the inter-satellite link for gravitational wave detection,an intelligent learning monitoring and fast warning method of the inter-satellite link control system failure is proposed.Different from the traditional fault diagnosis optimization algorithms,the fault intelligent learning method pro-posed in this paper is able to quickly identify the faults of inter-satellite link control system despite the existence of strong cou-pling nonlinearity.By constructing a two-layer learning network,the method enables efficient joint diagnosis of fault areas and fault parameters.The simulation results show that the average identification time of the system fault area and fault parameters is 0.27 s,and the fault diagnosis efficiency is improved by 99.8%compared with the traditional algorithm.
基金This project is supported by National Defense Science Foundation of China (No.614010).
文摘Through sampling and analyzing of plasma optic signals of 400-600 nm emitted from partial-penetration laser welding processes, how the penetration depth is related to the welding parameter and the plasma optic signal is studied, Under the experimental conditions, the plasma optic signal has good response to variety of the weld penetration, and the signal's RMS value increases with the penetration in a quadratic curve mode. The inherent relation between the plasma optic signal and the penetration depth is also analyzed. It is also found that, between the two common parameters of laser power and welding speed, laser power has more influence on penetration while welding speed has more influence on weld width. The research results provide theoretic and practical bases for penetration real-time monitoring or predicting in partial-penetration laser welding,
基金supported by the Military Chemistry and Pyrotechnics National Defense Specialty Fund for North University of China。
文摘In this paper,the solubility of 4-nitroimidazole in twelve pure solvents(toluene,benzene,1,4-dioxane,acetonitrile,ethyl acetate,acetone,GBL,ethanol,methanol,n-butanol,DMF and NMP)were determined by using the laser monitoring system from 278.15 K to 323.15 K under 101.1 k Pa,which are 0.00018–0.00070,0.00021–0.00073,0.00034–0.00092,0.00038–0.00142,0.00047–0.00120,0.00126–0.00303,0.00225–0.00517,0.00310–0.00724,0.00467–0.00982,0.00453–0.01940,0.01947–0.04652,and 0.04670–0.07452,respectively.At constant temperature,the mole fraction solubility of 4-nitroimidazole were increased as the following order:toluene<benzene<1,4-dioxane<(ethyl acetate or acetonitrile)<acetone<GBL<ethanol<(methanol or nbutanol)<DMF<NMP,and the solubility of 4-nitroimidazole in(ethyl acetate,acetonitrile)and(methanol,n-butanol)had an intersection point at 297.55 K and 281.85 K,respectively.The solubility of 4-nitroimidazole could be increased with increasing temperature in twelve pure solvents.The ideal model,modified Apelblat equation,polynomial empirical equation,andλh equation were used to correlate the experimental values.The experimental solubility values were employed to calculate the standard dissolution enthalpy,standard dissolution entropy and Gibbs energy.The dissolution of 4-nitroimidazole could be an endothermic process in twelve pure solvents.The determination and fitting solubility of 4-nitroimidazole have important guiding significance for the purification and crystallization of its preparation process.
基金This work was supported by the National High Tech-nology Research and Development Program of China (No. 2005AA641010)the National Natural Science Foundation of China (No. 50534050).
文摘Tunable diode laser absorption spectroscopy (TDLAS) has been widely employed in atmospheric trace gases detection. In the measurement of these trace gases, harmonic detection combined with a multi-pass white cell could remarkably enhance the detection sensitivity. In this paper, a portable TDLAS system built specifically for long time monitoring methane in the atmosphere is introduced. The detection limit is below 100 ppb that is enough for the monitoring of ambient methane, and the long time monitoring results obtained in Beijing are given, which is well coincident with that of the Fourier transform infrared (FTIR) spectroscopy.
文摘We report a wavelength and power monitoring system based on a scanning MEMS filter as wavelength discriminator and a near threshold-biased Fabry-Perot diode laser as wavelength reference. This system is capable of monitoring 250 channels of DWDM signal at 25 GHz ITU Grid with an error of less than ±8 pm.