During the last decades the whispering gallery mode based sensors have become a prominent solution for label-free sensing of various physical and chemical parameters.At the same time,the widespread utilization of the ...During the last decades the whispering gallery mode based sensors have become a prominent solution for label-free sensing of various physical and chemical parameters.At the same time,the widespread utilization of the approach is hindered by the restricted applicability of the known configurations for ambient variations quantification outside the laboratory conditions and their low affordability,where necessity on the spectrally-resolved data collection is among the main limiting factors.In this paper we demonstrate the first realization of an affordable whispering gallery mode sensor powered by deep learning and multi-resonator imaging at a fixed frequency.It has been shown that the approach enables refractive index unit(RIU)prediction with an absolute error at 3×10^(-6) level for dynamic range of the RIU variations from 0 to 2×10^(-3) with temporal resolution of several milliseconds and instrument-driven detection limit of 3×10−5.High sensing accuracy together with instrumental affordability and production simplicity places the reported detector among the most cost-effective realizations of the whispering gallery mode approach.The proposed solution is expected to have a great impact on the shift of the whole sensing paradigm away from the model-based and to the flexible self-learning solutions.展开更多
In order to study the extraction and acceleration mechanism of the dual-stage grid,a three-dimensional model based on the Particle-In-Cell/Monte Carlo Collision(PIC/MCC)method is performed.Dual-stage grid ion thruster...In order to study the extraction and acceleration mechanism of the dual-stage grid,a three-dimensional model based on the Particle-In-Cell/Monte Carlo Collision(PIC/MCC)method is performed.Dual-stage grid ion thruster is a new type of electrostatic ion thruster,which can break through the limitations of traditional gridded ion thrusters,and greatly improve the specific impulse.The high performance also makes the grid sensitive to operating parameters.In this paper,the influence of grid parameters on xenon ion thruster’s performance in a wide range is systematically simulated,and the optimal operating condition is given.Both the over-focusing of the plume,and the transparency of the screen grid are improved,and the grid corrosion is reduced through simulation optimization.The specific impulse under the given working conditions is 9877.24 s and the thrust is 7.28 mN.Based on the simulation optimization,the limitation of the dual-stage grid is discussed.The grid performs well under high voltage conditions(>3000 V)but not well under low voltage conditions(<2000 V).Finally,since argon is cheaper and more advantageous in future engineering applications,the plasma distribution and grid extraction ability under xenon and argon are analyzed and compared to study the flexibility of the dual-stage grid ion thruster.The simulation results show that a set of optimal parameters is only applicable to the corresponding propellant,which needs to be optimized for different propellant types.展开更多
In this paper,the abnormal experimental phenomenon on barrel erosion under extreme working conditions in the ultra-long life experiment(>10000 h)of ion thruster ion optics is studied by the Immersed-Finite-Element ...In this paper,the abnormal experimental phenomenon on barrel erosion under extreme working conditions in the ultra-long life experiment(>10000 h)of ion thruster ion optics is studied by the Immersed-Finite-Element Particle-In-Cell Monte-Carlo-Collision(IFE-PIC-MCC)method and the grid erosion evaluation model.The transport process of beam ions and Charge Exchange(CEX)ions in the grid system,and the characteristics and mechanisms of the aperture barrel erosion under extreme erosion conditions(i.e.the cylindrical erosion and chamfer erosion)were systematically studied.Thanks to the advantage of the IFE method for dealing with complex boundaries in structured mesh,the aperture barrel erosion morphology of the accelerator grid is reconstructed accurately based on the experimental results.The results show that,with the evolution of working conditions,the mechanism of the aperture barrel erosion changes significantly,which relies heavily on the accelerator grid morphology.The change of the accelerator grid aperture barrel morphology has a significant effect on the behavior of CEX ions,and only affects the local electric field distribution,but has no effect on the upstream plasma sheath.As the erosion progresses,the erosion position moves downstream along the grid aperture axis direction,and the erosion range becomes narrower.Regardless of the erosion phase,the erosion rate of the CEX ions located downstream of the decelerator grid is the largest.The erosion rate is related to the mean incident energy and angle,and their variation is closely related to the position and trajectory of CEXions.展开更多
The per-and polyfluoroalkyl substances(PFAS)are a group of organofluorine chemicals treated as the emerging pollutants that are currently of particularly acute concern.These compounds have been employed intensively as...The per-and polyfluoroalkyl substances(PFAS)are a group of organofluorine chemicals treated as the emerging pollutants that are currently of particularly acute concern.These compounds have been employed intensively as surfactants over multiple decades and are already to be found in surface and ground waters at amounts sufficient to have an effect on human health and ecosystems.Because of the carbon–fluorine bonds,the PFAS have an extreme environmental persistence and their negative impact accumulates with further production and penetration into the environment.In Germany alone,more than thousands of sites have been identified as contaminated with PFAS;thus,timely detection of PFAS residue is becoming a high priority.In this paper,we report on the high performance optical detection method based on whispering gallery mode(WGM)microcavities applied for the first time to detect PFAS contaminants in aqueous solutions.A self-sensing boosted 4D microcavity fabricated with two-photon polymerization is employed as an individual sensing unit.In an example of the multiplexed imaging sensor with multiple hundreds of simultaneously interrogated microcavities we demonstrate the possibility to detect the PFAS chemicals representatives at a level down to 1 ppb(parts per billion).展开更多
Water monitoring,environmental analysis,cell culture stability,and biomedical applications require precise pH control.Traditional methods,such as pH strips and meters,have limitations:pH strips lack precision,whereas ...Water monitoring,environmental analysis,cell culture stability,and biomedical applications require precise pH control.Traditional methods,such as pH strips and meters,have limitations:pH strips lack precision,whereas electrochemical meters,although more accurate,are fragile,prone to drift,and unsuitable for small volumes.In this paper,we propose a method for the optical detection of pH based on a multiplexed sensor with 4D microcavities fabricated via two-photon polymerization.This approach employs pH-triggered reversible variations in microresonator geometry and integrates hundreds of dual optically coupled 4D microcavities to achieve the detection limit of 0.003 pH units.The proposed solution is a clear example of the use-case-oriented application of two-photon polymerized structures of high optical quality.Owing to the benefits of the multiplexed imaging platform,the dual 4D microresonators can be integrated with other microresonator types for pH-corrected biochemical studies.展开更多
文摘During the last decades the whispering gallery mode based sensors have become a prominent solution for label-free sensing of various physical and chemical parameters.At the same time,the widespread utilization of the approach is hindered by the restricted applicability of the known configurations for ambient variations quantification outside the laboratory conditions and their low affordability,where necessity on the spectrally-resolved data collection is among the main limiting factors.In this paper we demonstrate the first realization of an affordable whispering gallery mode sensor powered by deep learning and multi-resonator imaging at a fixed frequency.It has been shown that the approach enables refractive index unit(RIU)prediction with an absolute error at 3×10^(-6) level for dynamic range of the RIU variations from 0 to 2×10^(-3) with temporal resolution of several milliseconds and instrument-driven detection limit of 3×10−5.High sensing accuracy together with instrumental affordability and production simplicity places the reported detector among the most cost-effective realizations of the whispering gallery mode approach.The proposed solution is expected to have a great impact on the shift of the whole sensing paradigm away from the model-based and to the flexible self-learning solutions.
基金co-supported by the National Key R & D Program for Intergovernmental International Scientific and Technological Innovation Cooperation,China(No. 2021YFE0116000)the National Natural Science Foundation of China (Nos. 12175032, 12102082 and 12275044),the National Natural Science Foundation of China+5 种基金the Belarusian Republican Foundation for Fundamental Research (No. 12211530449)the Fundamental Research Funds for the Central Universities of China (No. DUT22QN232)the S&T Program of Hebei, China (Nos. YCYZ202201 and 216Z1901G)the S&T Innovation Program of Hebei, China (Nos. SJMYF2022X18 and SJMYF2022X06)the Science and Technology Project of Hebei Education Department, China (No. ZC2023144)S&T Program of Langfang, China (No. 2022011039)
文摘In order to study the extraction and acceleration mechanism of the dual-stage grid,a three-dimensional model based on the Particle-In-Cell/Monte Carlo Collision(PIC/MCC)method is performed.Dual-stage grid ion thruster is a new type of electrostatic ion thruster,which can break through the limitations of traditional gridded ion thrusters,and greatly improve the specific impulse.The high performance also makes the grid sensitive to operating parameters.In this paper,the influence of grid parameters on xenon ion thruster’s performance in a wide range is systematically simulated,and the optimal operating condition is given.Both the over-focusing of the plume,and the transparency of the screen grid are improved,and the grid corrosion is reduced through simulation optimization.The specific impulse under the given working conditions is 9877.24 s and the thrust is 7.28 mN.Based on the simulation optimization,the limitation of the dual-stage grid is discussed.The grid performs well under high voltage conditions(>3000 V)but not well under low voltage conditions(<2000 V).Finally,since argon is cheaper and more advantageous in future engineering applications,the plasma distribution and grid extraction ability under xenon and argon are analyzed and compared to study the flexibility of the dual-stage grid ion thruster.The simulation results show that a set of optimal parameters is only applicable to the corresponding propellant,which needs to be optimized for different propellant types.
基金supported by the National Key R & D Program of China (No. 2020YFC2201100)the National Key R & D Program for Intergovernmental International Scientific and Technological Innovation Cooperation, China (No. 2021YFE0116000)+5 种基金the National Natural Science Foundation of China (Nos. 12175032, 12102082, 12275044, 12211530449)the Fundamental Research Funds for the Central Universities of China (Nos. DUT21GJ206 and DUT22QN232)the S & T Program of Hebei, China (Nos. YCYZ202201, 216Z1901G and 206Z1902G)the S & T Innovation Program of Hebei, China (Nos. SJMYF2022X18 and SJMYF2022X06)the Advanced Space Propulsion Laboratory of BICE and Beijing Engineering Research Center of Efficient and Green Aerospace Propulsion Technology, China (No. Lab ASP-2020-06)the Funded by Science and Technology Project of Hebei Education Department, China (No. ZC2023144)
文摘In this paper,the abnormal experimental phenomenon on barrel erosion under extreme working conditions in the ultra-long life experiment(>10000 h)of ion thruster ion optics is studied by the Immersed-Finite-Element Particle-In-Cell Monte-Carlo-Collision(IFE-PIC-MCC)method and the grid erosion evaluation model.The transport process of beam ions and Charge Exchange(CEX)ions in the grid system,and the characteristics and mechanisms of the aperture barrel erosion under extreme erosion conditions(i.e.the cylindrical erosion and chamfer erosion)were systematically studied.Thanks to the advantage of the IFE method for dealing with complex boundaries in structured mesh,the aperture barrel erosion morphology of the accelerator grid is reconstructed accurately based on the experimental results.The results show that,with the evolution of working conditions,the mechanism of the aperture barrel erosion changes significantly,which relies heavily on the accelerator grid morphology.The change of the accelerator grid aperture barrel morphology has a significant effect on the behavior of CEX ions,and only affects the local electric field distribution,but has no effect on the upstream plasma sheath.As the erosion progresses,the erosion position moves downstream along the grid aperture axis direction,and the erosion range becomes narrower.Regardless of the erosion phase,the erosion rate of the CEX ions located downstream of the decelerator grid is the largest.The erosion rate is related to the mean incident energy and angle,and their variation is closely related to the position and trajectory of CEXions.
基金Bundesministerium für Bildung und Forschung(03VP08220)。
文摘The per-and polyfluoroalkyl substances(PFAS)are a group of organofluorine chemicals treated as the emerging pollutants that are currently of particularly acute concern.These compounds have been employed intensively as surfactants over multiple decades and are already to be found in surface and ground waters at amounts sufficient to have an effect on human health and ecosystems.Because of the carbon–fluorine bonds,the PFAS have an extreme environmental persistence and their negative impact accumulates with further production and penetration into the environment.In Germany alone,more than thousands of sites have been identified as contaminated with PFAS;thus,timely detection of PFAS residue is becoming a high priority.In this paper,we report on the high performance optical detection method based on whispering gallery mode(WGM)microcavities applied for the first time to detect PFAS contaminants in aqueous solutions.A self-sensing boosted 4D microcavity fabricated with two-photon polymerization is employed as an individual sensing unit.In an example of the multiplexed imaging sensor with multiple hundreds of simultaneously interrogated microcavities we demonstrate the possibility to detect the PFAS chemicals representatives at a level down to 1 ppb(parts per billion).
基金the German Federal Ministry for Research and Education(BMBF)for partially funding this work under the VIP+-Programme in the project IntellOSS,03VP08220.
文摘Water monitoring,environmental analysis,cell culture stability,and biomedical applications require precise pH control.Traditional methods,such as pH strips and meters,have limitations:pH strips lack precision,whereas electrochemical meters,although more accurate,are fragile,prone to drift,and unsuitable for small volumes.In this paper,we propose a method for the optical detection of pH based on a multiplexed sensor with 4D microcavities fabricated via two-photon polymerization.This approach employs pH-triggered reversible variations in microresonator geometry and integrates hundreds of dual optically coupled 4D microcavities to achieve the detection limit of 0.003 pH units.The proposed solution is a clear example of the use-case-oriented application of two-photon polymerized structures of high optical quality.Owing to the benefits of the multiplexed imaging platform,the dual 4D microresonators can be integrated with other microresonator types for pH-corrected biochemical studies.
