The efficacy of spacecraft propulsion systems significantly depends on the choice of propellant.This study utilized laser-induced breakdown spectroscopy(LIBS)to investigate the impact of different fuel types,fuel rati...The efficacy of spacecraft propulsion systems significantly depends on the choice of propellant.This study utilized laser-induced breakdown spectroscopy(LIBS)to investigate the impact of different fuel types,fuel ratios,and laser energies on the plasma parameters of ammonium dinitramide(ADN)-based liquid propellants.Our findings suggest that 1-allyl-3-methylimidazolium dicyanamide(AMIMDCA)as a fuel choice led to higher plasma temperatures compared to methanol(CH_3OH)and hydroxyethyl hydrazine nitrate(HEHN)under the same experimental conditions.Optimization of the fuel ratio proved critical,and when the AMIMDCA ratio was 21wt.%the propellants could achieve the best propulsion performance.Increasing the incident laser energy not only enhanced the emission spectral intensity but also elevated the plasma temperature and electron density,thereby improving ablation efficiency.Notably,a combination of 100 mJ laser energy and 21wt.%AMIMDCA fuel produced a strong and stable plasma signal.This study contributes to our knowledge of pulsed laser micro-ablation in ADN-based liquid propellants,providing a useful optical diagnostic approach that can help refine the design and enhance the performance of spacecraft propulsion systems.展开更多
Double-pulse LIBS is a promising technique for deep-sea applications.LIBS measurements in shallow water with up to 400 mJ each pulse were done to select laser parameters which promote optimized spectral line emission ...Double-pulse LIBS is a promising technique for deep-sea applications.LIBS measurements in shallow water with up to 400 mJ each pulse were done to select laser parameters which promote optimized spectral line emission from plasma even at elevated pressures,where line broadening until loss of most of the spectral information can occur.Optical emission spectroscopy,using a Czerny-Turner spectrometer,has been applied to investigate the dependence of the emitted radiation on laser parameters and hydrostatic pressure.It has been found,that higher laser pulse energies,especially with short pulse delay as required in high water pressure,can also have an adverse effect on the measured spectrum.展开更多
The precise measurement of Al, Mg, Ca, and Zn composition in copper slag is crucial for effective process control of copper pyrometallurgy. In this study, a remote laser-induced breakdown spectroscopy(LIBS) system was...The precise measurement of Al, Mg, Ca, and Zn composition in copper slag is crucial for effective process control of copper pyrometallurgy. In this study, a remote laser-induced breakdown spectroscopy(LIBS) system was utilized for the spectral analysis of copper slag samples at a distance of 2.5 m. The composition of copper slag was then analyzed using both the calibration curve(CC) method and the partial least squares regression(PLSR) analysis method based on the characteristic spectral intensity ratio. The performance of the two analysis methods was gauged through the determination coefficient(R^(2)), average relative error(ARE), root mean square error of calibration(RMSEC), and root mean square error of prediction(RMSEP). The results demonstrate that the PLSR method significantly improved both R^(2) for the calibration and test sets while reducing ARE, RMSEC, and RMSEP by 50% compared to the CC method. The results suggest that the combination of LIBS and PLSR is a viable approach for effectively detecting the elemental concentration in copper slag and holds potential for online detection of the elemental composition of high-temperature molten copper slag.展开更多
Metallic copper is widely used as current collector(CC) for graphite anode of lithium-ion batteries(LIBs) due to its high electrical conductivity and electrochemical stability. However, the large volume density of com...Metallic copper is widely used as current collector(CC) for graphite anode of lithium-ion batteries(LIBs) due to its high electrical conductivity and electrochemical stability. However, the large volume density of commercial copper foil(~8.9 g·cm^(-3)) limits the increase of energy density of battery. Here, copper-coated porous polyimide(Cu@PPI) was prepared by vacuum evaporation as collector for the graphite anode. The sandwich structure connects the copper metal on both sides of the collector with excellent electrical conductivity. Compared to commercial Cu foil, Cu@PPI has lighter mass(≤3.9 mg for disc of 12 mm diameter versus 9.9 mg of ~10 μm Cu foil) and lower volume density(≤3.3 g·cm^(-3)). In addition, the porous structure allows of better adhesion of reactive substances and electrochemical properties than pure Cu foils. It is estimated that the energy density of Cu@PPI should be much higher than that of Cu foil. This strategy should be applicable for other current collectors.展开更多
Laser-induced breakdown spectroscopy(LIBS)is a powerful technique for elemental analysis,offering rapid analysis,minimal sample preparation,wide elemental coverage,and portability.To enhance the detection sensitivity ...Laser-induced breakdown spectroscopy(LIBS)is a powerful technique for elemental analysis,offering rapid analysis,minimal sample preparation,wide elemental coverage,and portability.To enhance the detection sensitivity of LIBS,increasing the spectral emission intensity is crucial.This paper explores the use of Tesla coil(TC)discharge as an alternative to spark discharge in silicon LIBS.The study examines the influence of TC discharge on both time-integrated and timeresolved spectra,with and without TC discharge;the corresponding electron temperature and density are obtained.The results show that TC discharge significantly amplifies the spectral intensity,improving signal sensitivity in LIBS analysis.Specifically,in the laser energy range from 7.4 to 24.0 mJ,TC discharge increased the average spectral line intensities of Si(II)385.60 nm and Si(I)390.55 nm by factors of 8.4 and 5.1,respectively.Additionally,the average electron temperature and density were enhanced by approximately 3.2%and 4.2%,respectively,under TC discharge.The advantages of TC discharge include higher energy deposition,extended discharge duration,reduced electrode erosion,and enhanced safety.This research contributes to advancing LIBS technology and expanding its applications in various fields.展开更多
Only a small amount of spectral information is collected because the collection solid angle of the optical fiber probe and lens is very limited when collecting spectral information.To overcome this limitation,this stu...Only a small amount of spectral information is collected because the collection solid angle of the optical fiber probe and lens is very limited when collecting spectral information.To overcome this limitation,this study presents a novel method for acquiring plasma spectral information from various spatial directions.A parabolic-shaped plasma spectral collection device(PSCD)is employed to effectively collect more spectral information into the spectrometer,thereby enhancing the overall spectral intensity.The research objects in this study were soil samples containing different concentrations of heavy metals Pb,Cr,and Cd.The results indicate that the PSCD significantly enhances the spectral signal,with an enhancement rate of up to 45%.Moreover,the signal-to-noise ratio also increases by as much as 36%.Simultaneously,when compared to the absence of a device,it is found that there is no significant variation in plasma temperature when the PSCD is utilized.This observation eliminates the impact of the spatial effect caused by the PSCD on the spectral intensity.Consequently,a concentrationspectral intensity relationship curve is established under the PSCD.The results revealed that the linear fitting R^(2)for Pb,Cr,and Cd increased by 0.011,0.001,and 0.054,respectively.Additionally,the limit of detection(LOD)decreased by 0.361 ppm,0.901 ppm,and 0.602 ppm,respectively.These findings indicate that the spectral enhancement rate elevates with the increase in heavy metal concentration.Hence,the PSCD can effectively enhance the spectral intensity and reduce the detection limit of heavy metals in soil.展开更多
文摘The efficacy of spacecraft propulsion systems significantly depends on the choice of propellant.This study utilized laser-induced breakdown spectroscopy(LIBS)to investigate the impact of different fuel types,fuel ratios,and laser energies on the plasma parameters of ammonium dinitramide(ADN)-based liquid propellants.Our findings suggest that 1-allyl-3-methylimidazolium dicyanamide(AMIMDCA)as a fuel choice led to higher plasma temperatures compared to methanol(CH_3OH)and hydroxyethyl hydrazine nitrate(HEHN)under the same experimental conditions.Optimization of the fuel ratio proved critical,and when the AMIMDCA ratio was 21wt.%the propellants could achieve the best propulsion performance.Increasing the incident laser energy not only enhanced the emission spectral intensity but also elevated the plasma temperature and electron density,thereby improving ablation efficiency.Notably,a combination of 100 mJ laser energy and 21wt.%AMIMDCA fuel produced a strong and stable plasma signal.This study contributes to our knowledge of pulsed laser micro-ablation in ADN-based liquid propellants,providing a useful optical diagnostic approach that can help refine the design and enhance the performance of spacecraft propulsion systems.
基金funded by the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)–Project No.454848899。
文摘Double-pulse LIBS is a promising technique for deep-sea applications.LIBS measurements in shallow water with up to 400 mJ each pulse were done to select laser parameters which promote optimized spectral line emission from plasma even at elevated pressures,where line broadening until loss of most of the spectral information can occur.Optical emission spectroscopy,using a Czerny-Turner spectrometer,has been applied to investigate the dependence of the emitted radiation on laser parameters and hydrostatic pressure.It has been found,that higher laser pulse energies,especially with short pulse delay as required in high water pressure,can also have an adverse effect on the measured spectrum.
基金supported by funding for research activities of postdoctoral researchers in Anhui Provincespecial funds for developing Anhui Province’s industrial “three highs” and high-tech industries。
文摘The precise measurement of Al, Mg, Ca, and Zn composition in copper slag is crucial for effective process control of copper pyrometallurgy. In this study, a remote laser-induced breakdown spectroscopy(LIBS) system was utilized for the spectral analysis of copper slag samples at a distance of 2.5 m. The composition of copper slag was then analyzed using both the calibration curve(CC) method and the partial least squares regression(PLSR) analysis method based on the characteristic spectral intensity ratio. The performance of the two analysis methods was gauged through the determination coefficient(R^(2)), average relative error(ARE), root mean square error of calibration(RMSEC), and root mean square error of prediction(RMSEP). The results demonstrate that the PLSR method significantly improved both R^(2) for the calibration and test sets while reducing ARE, RMSEC, and RMSEP by 50% compared to the CC method. The results suggest that the combination of LIBS and PLSR is a viable approach for effectively detecting the elemental concentration in copper slag and holds potential for online detection of the elemental composition of high-temperature molten copper slag.
基金supported by the 2019 Foshan Science and Technology Innovation Team(No.1920001000108)Guangdong Basic and Applied Basic Research Foundation(No.2021A1515111103)+2 种基金Guangzhou Science and Technology Plan Project(No.202201010867)Science and Technology Major Project of Guangdong Province(No.220110165851234)the National Key R&D Program of China(No.2020YFB0408100).
文摘Metallic copper is widely used as current collector(CC) for graphite anode of lithium-ion batteries(LIBs) due to its high electrical conductivity and electrochemical stability. However, the large volume density of commercial copper foil(~8.9 g·cm^(-3)) limits the increase of energy density of battery. Here, copper-coated porous polyimide(Cu@PPI) was prepared by vacuum evaporation as collector for the graphite anode. The sandwich structure connects the copper metal on both sides of the collector with excellent electrical conductivity. Compared to commercial Cu foil, Cu@PPI has lighter mass(≤3.9 mg for disc of 12 mm diameter versus 9.9 mg of ~10 μm Cu foil) and lower volume density(≤3.3 g·cm^(-3)). In addition, the porous structure allows of better adhesion of reactive substances and electrochemical properties than pure Cu foils. It is estimated that the energy density of Cu@PPI should be much higher than that of Cu foil. This strategy should be applicable for other current collectors.
基金the support by the National Key Research and Development Program of China(No.2019YFA0307701)National Natural Science Foundation of China(Nos.11674128,11674124 and 11974138)。
文摘Laser-induced breakdown spectroscopy(LIBS)is a powerful technique for elemental analysis,offering rapid analysis,minimal sample preparation,wide elemental coverage,and portability.To enhance the detection sensitivity of LIBS,increasing the spectral emission intensity is crucial.This paper explores the use of Tesla coil(TC)discharge as an alternative to spark discharge in silicon LIBS.The study examines the influence of TC discharge on both time-integrated and timeresolved spectra,with and without TC discharge;the corresponding electron temperature and density are obtained.The results show that TC discharge significantly amplifies the spectral intensity,improving signal sensitivity in LIBS analysis.Specifically,in the laser energy range from 7.4 to 24.0 mJ,TC discharge increased the average spectral line intensities of Si(II)385.60 nm and Si(I)390.55 nm by factors of 8.4 and 5.1,respectively.Additionally,the average electron temperature and density were enhanced by approximately 3.2%and 4.2%,respectively,under TC discharge.The advantages of TC discharge include higher energy deposition,extended discharge duration,reduced electrode erosion,and enhanced safety.This research contributes to advancing LIBS technology and expanding its applications in various fields.
基金supported by Department of Science and Technology of Jilin Province of China(Nos.YDZJ202301 ZYTS481,202202901032GX,and 20230402068GH)。
文摘Only a small amount of spectral information is collected because the collection solid angle of the optical fiber probe and lens is very limited when collecting spectral information.To overcome this limitation,this study presents a novel method for acquiring plasma spectral information from various spatial directions.A parabolic-shaped plasma spectral collection device(PSCD)is employed to effectively collect more spectral information into the spectrometer,thereby enhancing the overall spectral intensity.The research objects in this study were soil samples containing different concentrations of heavy metals Pb,Cr,and Cd.The results indicate that the PSCD significantly enhances the spectral signal,with an enhancement rate of up to 45%.Moreover,the signal-to-noise ratio also increases by as much as 36%.Simultaneously,when compared to the absence of a device,it is found that there is no significant variation in plasma temperature when the PSCD is utilized.This observation eliminates the impact of the spatial effect caused by the PSCD on the spectral intensity.Consequently,a concentrationspectral intensity relationship curve is established under the PSCD.The results revealed that the linear fitting R^(2)for Pb,Cr,and Cd increased by 0.011,0.001,and 0.054,respectively.Additionally,the limit of detection(LOD)decreased by 0.361 ppm,0.901 ppm,and 0.602 ppm,respectively.These findings indicate that the spectral enhancement rate elevates with the increase in heavy metal concentration.Hence,the PSCD can effectively enhance the spectral intensity and reduce the detection limit of heavy metals in soil.
