High Collision Frequency Research Articles

A Two-Phase Hydrogenation Membrane for Contaminants Reduction at High Hydrogen Reagent Utilization Efficiency.

Heterogeneous hydrogenation is surging as a promising strategy for selective removal of water pollutants, yet numerous efforts rely on catalyst design to advance catalytic activity. Herein, we enhanced the mass transfer and the utilization of hydrogen reagent through construction of a two-phase flow-through membrane reaction device (Pd/SiC-MR). Pd/SiC-MR displays high efficiency and selectivity toward removal of multiple pollutants. For instance, rapid (∼0.35 s) and exclusive hydrogenation (>99%) of carbon-chlorine bond in organohalogens were realized at high water flux (220 L/m2/h). More importantly, the two-phase Pd/SiC-MR reaction system achieved 31.4% utilization of hydrogen reagent, 1-3 orders of magnitude higher than those by classical slurry or fixed-bed reactor. The high hydrogenation performance is attributed to the close proximity of the hydrogen source, reactive hydrogen atom, and pollutant under high molecular collision frequency in membrane pores. Our study opens an approach for improved hydrogen reagent utilization while reserving the high pollutant removal efficiency through altering operating conditions, beyond complex material design limitations in hydrogenation water purification.

Electroreduction of CO2 to HCOOH on 3D-Ag nanosheet array supported on carbon membrane

Regulating local CO2 concentration and pH near the catalytic active sites could induce effective reaction pathways for electroreduction of CO2 to chemicals. Here, a membrane nanofluid reactor for efficient electroreduction of CO2 to formic acid was prepared by constructing high-density active sites of 3D-Ag nanosheet array on the surface and within the pores of carbon membrane (3D-Ag NA/CM). The local microenvironment of CO2 and H+ concentration was controlled by adjusting the pore size, CO2 flow rate, and mass transfer mode. In the flow-through mode, the CO2 was electro-reduced to formic acid with Faraday efficiency of 94% and the partial current density of 35.8 mA/cm2. Both the selectivity and activity were higher than those in flow-by mode. The low local concentration of CO2 in the channel was the key to the high selectivity of formic acid. When CO2 flowed through the membrane nanopores, the high collision frequency of CO2 with catalyst on the pore walls facilitated the electroreduction of CO2. It found that the presence of OV promoted the adsorption of CO2 and reduced the energy barrier for its activation into ∗CHOO. It lays a foundation for the research on optimizing the performance of CO2 electroreduction with nanofluid reactors.

Assessment of the impact of fuelling puff location on divertor impurity compression and enrichment in STEP

In order to achieve a compatible solution between the divertors and the core, SOLPS-ITER simulations were performed in a Spherical Tokamak for Energy Production (STEP) connected double-null geometry to investigate the possibility of using deuterium ( D2 ) puff locations as an actuator for divertor argon (Ar) compression/enrichment. It was found that puffing D2 from the inner-midplane (IMP) D2 puff enhanced Ar compression and enrichment on the high-field-side (HFS) and lowered the required upstream Ar fraction to achieve acceptable target conditions. An interesting link was found between argon compression and the number of stagnation points of the middle-charge-state Ar ions in the HFS SOL, Nst ; significantly improved compression and enrichment were obtained for Nst=1 (corresponding mostly to the cases with IMP puff) compared to Nst=3 (corresponding mostly to the cases without IMP puff). An intermediate compression and enrichment was obtained when Nst=5 . The change of Nst from 3 to 1 (or 5) was achieved by a combination of D+ outflow, high collision frequency, and flipped temperature gradients around the IMP. Given a possible drawback of ΓDOMP+IMP , that is a direct effect on the upstream main plasma density and temperature, we propose ΓDPFR+IMP as the best solution, balancing the negative and positive effects of private-flux-region and IMP D2 puffs. Further studies will be carried out both experimentally and numerically.

Effect of laser wavelength on ablation propulsion and plasma characteristics with acrylonitrile butadiene styrene target

Propulsion performance produced by laser ablation of polymer made of acrylonitrile butadiene styrene is experimentally investigated using the first, second, and third harmonics of a Nd: YAG laser. A ballistic pendulum is employed to assess the impulse and coupling coefficient for laser propulsion application. Fast photography, target ablation, and optical emission spectroscopy are proposed to analyze the energy coupling characteristic. The impulse and coupling coefficient under different pressures are demonstrated to depend on the target ablation and plasma properties which are relevant to laser wavelength. As the laser wavelength decreases, the crater depth and ablation mass are enhanced. Meanwhile, the plasma plume separates at atmospheric pressure and its length extends continuously in the low-pressure range. As a result, plasma including more ejected particles with higher velocity contributes to obtaining excellent impulse and coupling coefficient. In addition, the decreased electron density and temperature indicate higher collision frequency and photoionization dominate rather than inverse bremsstrahlung absorption at shorter laser wavelengths. This work provides a better understanding of the energy conversion mechanism and a reference for improving propulsion performance.

Propagation characteristics of obliquely incident terahertz waves in inhomogeneous microplasma

The transmission characteristics of terahertz (THz) waves in a non-uniform microplasma are investigated by using the scattering matrix method. The electron density distribution in microplasma is simulated by Epstein and parabolic models. The effects of physical parameters, such as the incidence angle of THz waves, microplasma size, electron density, and collision frequency, on the propagation of THz waves are numerically analyzed. The results show that lower frequency THz waves are difficult to penetrate the microplasma with high electron density and high collision frequency. The microplasma density distribution, especially the gradient variation of the density in the first layer, has a large effect on the reflection of THz waves. Thus, THz waves can be used to diagnose the physical parameters of microplasmas.

Estimation of mean electron energy in helium surface ionization waves on dielectric substrates

The determination of basic plasma parameters in atmospheric pressure discharges is critical to advancing their use in applications. Atmospheric pressure plasma jets have found use in the fields of medicine, agriculture, material modification and others. Atmospheric pressure plasma jets often generate plasma surface ionization waves (SIW) which interact with and propagate over surfaces. Electrical diagnostics are challenging in SIW due to high collision frequencies and small scale of the plasma discharge. This work employs a passive optical emission line ratio technique to estimate the mean electron energy in SIW over planar dielectric substrates. The method uses an intensity ratio of two helium triplet lines: He( 33S ) at 706.5 nm and He( 33D ) at 587.56 nm. A collisional-radiative model is used to correlate line ratio to mean electron energy and determine dependencies on electron density and He/air gas mixture. Mean electron energies ranging from 3–8 eV are determined in He/air mixtures and are found to remain constant as the surface wave propagates radially. This work provides a 2D, time-resolved, mean electron energy diagnostic for surface ionization wave propagation and validation of numerical modeling in atmospheric pressure systems with spatially varying He/air gas mixtures. The model in question is designed for use with any He line ratio in the n = 3 excitation level.

Low energy femtosecond pulsed laser ablation of Nd:YAG laser crystal in high-pressure oxygen and nitrogen background gas

A low-energy femtosecond (fs) pulsed laser was utilized to ablate the Nd:YAG laser crystal target in high-pressure oxygen (O2) and nitrogen (N2) background gases. Only minute amounts of neodymium (Nd), yttrium (Y), and aluminum (Al) were detected in the deposited material due to the thermalization resulting from low laser pulse energy and significant scattering caused by the high background gas pressure. We used a collision-based model and peak-fitting method of the angular distribution of the plume to explain the result. The collision-based model was used to explain and determine the probability distribution of the elements arriving from the target to the substrate. The magnitude of the probability distribution obtained with O2 background gas is higher as compared to N2 background gas owing to the former’s higher collision frequency. The peak-fitting method of the angular distribution of Nd, Y, and Al provided better approximations of the ratio of atoms arriving after ablation as compared to the collision-based model. Further improvements can be carried out to better predict the deposited material ratio.

Mechanism and Experimental Investigation of Vibration Reduction for Container Cranes Based on Particle Damping Technology

Container cranes have been widely used for port operation. However, the structure of the port container crane is large, which always leads to crane damage under vibration and strong wind. Therefore, a method for vibration reduction of container crane structure based on particle damping technology is proposed. In this investigation, the scale 1:80 crane model is built, and the equivalent mechanical model is also established to preliminarily verify the effect of vibration suppression. Furthermore, the dependence of vibration suppression effect on the key parameters of the damper, i.e., filling material, filling rate, particle size, and installation position of dampers are analyzed through experiments. The results indicate that the vibration peak of the crane structure displayed in the Simulink oscilloscope is weakened and lags behind, the installation of the damper brings the effect of vibration suppression for the crane, and the vibration suppression effect reaches 25%; the crane mode obtains the best vibration suppression effect under the condition that the material filled in the damper has a large density and elastic modulus, sufficient collision space and high collision frequency, and the dampers are installed far away from the crane center of gravity. The optimum parameters of the damper obtained from experiments were 12 mm lead beads, a filling rate of 60%, installed in the distal ends within the strength range of the forearm of the crane. It is thus concluded that particle damping technology has provided an effective way of wind and vibration reduction for container cranes.

Low temperature reaction kinetics inside an extended Laval nozzle: REMPI characterization and detection by broadband rotational spectroscopy.

Chirped-Pulse Fourier-Transform millimeter wave (CP-FTmmW) spectroscopy is a powerful method that enables detection of quantum state specific reactants and products in mixtures. We have successfully coupled this technique with a pulsed uniform Laval flow system to study photodissociation and reactions at low temperature, which we refer to as CPUF ("Chirped-Pulse/Uniform flow"). Detection by CPUF requires monitoring the free induction decay (FID) of the rotational coherence. However, the high collision frequency in high-density uniform supersonic flows can interfere with the FID and attenuate the signal. One way to overcome this is to sample the flow, but this can cause interference from shocks in the sampling region. This led us to develop an extended Laval nozzle that creates a uniform flow within the nozzle itself, after which the gas undergoes a shock-free secondary expansion to cold, low pressure conditions ideal for CP-FTmmW detection. Impact pressure measurements, commonly used to characterize Laval flows, cannot be used to monitor the flow within the nozzle. Therefore, we implemented a REMPI (resonance-enhanced multiphoton ionization) detection scheme that allows the interrogation of the conditions of the flow directly inside the extended nozzle, confirming the fluid dynamics simulations of the flow environment. We describe the development of the new 20K extended flow, along with its characterization using REMPI and computational fluid dynamics. Finally, we demonstrate its application to the first low temperature measurement of the reaction kinetics of HCO with O2 and obtain a rate coefficient at 20K of 6.66 ± 0.47 × 10-11cm3 molec-1s-1.

Experimentally-measured rate parameters for vibrational quenching of CO by N2

Carbon monoxide is a trace species in Titan's atmosphere that is not consistently found in local thermodynamic equilibrium at all altitudes. Understanding how CO exchanges energy with atmospheric collision partners is therefore crucial for accurate atmospheric modelling. Particularly significant could be vibrational relaxation of CO by nitrogen due to the high collision frequency in Titan's N2-based atmosphere. Some CO(v)-N2 rate coefficients have never been experimentally measured while others were measured decades ago in low-precision experiments. In this work, we present precise experimental measurements of the rate coefficients for the quenching of CO(v = 1,2) by N2. To perform the experiment, an equilibrium mixture of CO, N2, O3, and bath gases was subjected to a temperature-jump, creating a small amount of vibrationally-excited CO. Transient diode laser absorption spectroscopy was then used to observe the evolving vibrational state populations as a function of time. The rate coefficients of interest were found by measuring quenching rate as a function of quencher concentrations. The rate coefficient for quenching of CO(v = 1) by N2 was measured to be k = (1.3 ± 0.2) x 10−14 cm3 molecule−1 s−1 and the rate coefficient for quenching of CO(v = 2) by N2 was measured to be k = (2.1 ± 0.5) x 10−13 cm3 molecule−1 s−1 at 315 K.

Intramolecular Accelerated Assembly of Molecular Beacons: A DNA Nanoarchitecture-based Spatial Confinement Strategy toward Terminal Deoxynucleotidyl Transferase Biosensing.

Physiological function analysis of terminal deoxynucleotidyl transferase (TdT) in clinical medicine and hematopathology highlights its significance to be extensively utilized as a diagnostic biomarker for leukemia diagnosis. Herein, taking advantage of the spatial-confinement effect on a three-dimensional (3D) DNA nanoarchitecture, we reported a target-triggered intramolecular accelerated molecular beacon (MB) assembly for rapid and real-time analysis of TdT activity. In this strategy, the 3D DNA nanoarchitecture is first engineered via a cross-linking network hybridization chain reaction (HCR). A number of MBs, which were designed with a polythymine (poly-T) loop, were then conjugated on the scaffold DNA nanoarchitecture, allowing the obtained MB-DNA nanoarchitecture to contain lots of free 3'-hydroxyl (OH) termini inside or outside the super DNA nanostructure. Moreover, the distance between different MBs is closed, and the local concentration of MB is significantly improved owing to the confinement of MBs on this DNA nanoarchitecture. Once encountered with target TdT, the free -OH groups can be recognized by TdT immediately to catalyze the template-independent incorporation of adenine nucleotides, which results in the generation of multiple poly-A chains that rapidly react with many MBs via an intramolecular accelerated assembly process. The time-dependent substantial enhancement of the fluorescence from MBs can thus be applied for robustly analyzing TdT. Our observations suggest that the DNA nanostructure-based spatial confinement effect enables a high molecular collision frequency to accelerate the reaction kinetics, and the super DNA nanoarchitecture exhibits a better nuclease resistance to maintain signal stability. With these advantages, TdT can be rapidly detected with high sensitivity, specificity, and biostability.

Efficiency of Magnetohydrodynamic Wave Generation in Weakly Ionized Atmospheres

The generation of Alfvén and slow magnetoacoustic waves in weakly ionized atmospheres by excitation of the charges-only component of the two-fluid (charge and neutral) plasma is shown to be more or less efficient depending on the energy fraction initially allocated to the three stationary flow differential modes, which characterize the inter-species drift. This is explained via detailed analysis of the full 10-dimensional spectral description of two-fluid linear magnetohydrodynamics. Excitation via the velocity of the charges only is found to be very inefficient, in accord with previous results, while excitation via the magnetic field perturbation alone is highly efficient. All 10 eigenvalues and eigenvectors are presented analytically in the high collision frequency regime.

Electron trajectories in a collisional crossed-field gap

The Hull cutoff represents the maximum magnetic field in a vacuum crossed-field gap (CFG) such that an electron emitted from the cathode reaches the anode. Prior studies demonstrated that introducing ions into a CFG always causes increased excursion of electrons toward the anode. In this paper, we assess a collisional CFG by incorporating collision frequency into the electron force law. The theoretical electron trajectories agree well with a one-dimensional particle-in-cell simulation and demonstrate that emitted electrons always cross a collisional CFG. We derive a modified Hull cutoff condition for a collisional CFG corresponding to an electron reaching the anode with zero velocity in the direction of the electric field. Rather than representing the threshold for magnetic insulation, this condition gives the maximum magnetic field and maximum collision frequency for which an electron reaches the anode without turning around; higher magnetic fields and/or collision frequencies cause the electron to turn around before crossing the gap. Further increasing either quantity causes the electron to change direction more frequently as it crosses the gap, noticeably increasing the transit time with each change in electron direction. In the limit of high collision frequency, the electron velocity across the gap approaches a constant, meaning that electrons will reach the anode at nonzero velocity. The transit time above this condition increases smoothly and monotonically with increasing magnetic field or collision frequency. These results elucidate the implications of collisions on magnetic insulation for future assessments of the limiting current in a collisional CFG.

Effects of High-collision Plasma on Radiation Protection of Human Brain

Objective: The purpose of this paper is to find a reasonable composite structure of electromagnetic protection device, especially the distribution characteristics of plasma parameters and operation conditions. Methods: Due to its high collision frequency, the high-pressure discharge plasma can be usedas a filling medium to take the electromagnetic protection effect. The strategies and algorithmsare presented to solve the propagation characteristics of electromagnetic wave (EMW) in plasma with complex dielectric constant. When the real and imaginary part of permittivity are of the same order of magnitude, the imaginary part value will impact on the feature of plasma dielectric constant, also affect the behavior of propagation of EMW. The propagation process of EMW in virtual human brain (VHB) model is investigated by finite difference time domain method. By optimizing the layout of plasma layer and air layer, an effective phase regulator is constructed, and the reflected wave amplitude is greatly reduced. Results: The simulation results show that plasma makes the amplitude of the electromagnetic fields in VHB decrease to different degrees. their maximum average decrease is about 25% and the corresponding reduction of SAR value is more than 40% in the frequency range of 1.8-3.6GHz. Conclusion: The existence of plasma can make the scalp and muscle possess the excellent performance in resisting the incident of EMW, so that the amplitude of the electromagnetic field inside the brain body is small, so as to effectively protect the brain tissue. These research results have good reference value and engineering applicability for the structure design of protection equipment with high frequency of EMW.

Free-standing membrane incorporating single-atom catalysts for ultrafast electroreduction of low-concentration nitrate

The release of wastewaters containing relatively low levels of nitrate (NO3-) results in sufficient contamination to induce harmful algal blooms and to elevate drinking water NO3- concentrations to potentially hazardous levels. In particular, the facile triggering of algal blooms by ultra-low concentrations of NO3- necessitates the development of efficient methods for NO3- destruction. However, promising electrochemical methods suffer from weak mass transport under low reactant concentrations, resulting in long treatment times (on the order of hours) for complete NO3- destruction. In this study, we present flow-through electrofiltration via an electrified membrane incorporating nonprecious metal single-atom catalysts for NO3- reduction activity enhancement and selectivity modification, achieving near-complete removal of ultra-low concentration NO3- (10 mg-N L-1) with a residence time of only a few seconds (10 s). By anchoring Cu single atoms supported on N-doped carbon in a carbon nanotube interwoven framework, we fabricate a free-standing carbonaceous membrane featuring high conductivity, permeability, and flexibility. The membrane achieves over 97% NO3- removal with high N2 selectivity of 86% in a single-pass electrofiltration, which is a significant improvement over flow-by operation (30% NO3- removal with 7% N2 selectivity). This high NO3- reduction performance is attributed to the greater adsorption and transport of nitric oxide under high molecular collision frequency coupled with a balanced supply of atomic hydrogen through H2 dissociation during electrofiltration. Overall, our findings provide a paradigm of applying a flow-through electrified membrane incorporating single-atom catalysts to improve the rate and selectivity of NO3- reduction for efficient water purification.

Pathophysiological and motor factors associated with collision avoidance behavior in individuals with stroke.

High collision rates and frequency of entering the opening from non-paretic sides are associated with collision in individuals with stroke. To identify factors associated with collision avoidance behavior when individuals with stroke walked through narrow openings. Participants with subacute or chronic stroke walked through a narrow opening and had to avoid colliding with obstacles. Multiple regression analyses were conducted with pathophysiology, motor function, and judgment ability as predictor variables; collision rate and frequency of entering the opening from non-paretic sides were outcome variables. Sixty-one eligible individuals with stroke aged 63±12 years were enrolled. Thirty participants collided twice or more and 37 entered the opening from the non-paretic side. Higher collision occurrence was associated with slower Timed Up and Go tests and left-right sway (odds ratios, 1.2 and 5.6; 95% confidence intervals, 1.1-1.3 and 1.3-28.2; p = .008 and.025, respectively). Entering from non-paretic sides was associated with lesions in the thalamus, left-sided hemiplegia, and Brunnstrom stage 3 or lower (odds ratios, 6.6, 8.7, and 6.7; 95% confidence intervals, 1.3-52.5, 2.5-36.5, and 1.2-57.5; and p = .038,.001, and.048, respectively). Walking ability is associated with avoiding obstacle collision, while pathophysiological characteristics and degree of paralysis are associated with a preference for which side of the body enters an opening first. Interventions to improve walking ability may improve collision avoidance. Avoidance behavior during intervention varies depending on the lesion position.

Spatiotemporal Patterns of Cyclist Collisions in Germany: Variations in Frequency, Severity of Injury, and Type of Collision in 2019

Cycling has gained increasing interest in Germany in recent years due to its manifold environmental, societal, and economic benefits. However, the number of cyclist collisions resulting in injury or death remains high and little is known about regional variations in frequency, severity of injury, and type of collision. This study investigates spatial and temporal patterns and characteristics of cyclist collisions across Germany in 2019. Using a detailed cyclist collision dataset for most German federal states, we identified statistically significant regional differences in frequency, severity of injury, and type of collision. To facilitate this and future cyclist collision surveillance studies in Germany, we developed and published a custom R package to download and combine the collision data with geographical data. Our analysis reveals that densely populated regions exhibit higher collision rates and a higher share of collisions involving turns, but lower severity of injuries and a lower share of collisions whilst driving in a straight line, a higher collision frequency during the work week compared to weekends, and a higher collision frequency peak during morning rush hour. We also observed a markedly high share of fatal bicycle-truck collisions in densely populated regions. In contrast, rural regions show lower collision rates, but a higher share of severe collisions, a higher share of collisions whilst driving in a straight line, as well as higher collision frequencies during weekends and summer months. Our findings underscore the complex and multifaceted geographical variations in collisions involving cyclists. The results of this study suggest that a one-size-fits-all approach to collision prevention infrastructure and policy may be insufficient for addressing variations in risk, and that future efforts to improve cyclist safety should be tailored to the local geographical context.

Spatial and temporal distribution of bat mortality on a highway in southeast Brazil

Roads and highways can work as barriers to the movement of many species, thereby preventing the individuals from accessing feeding and reproduction sites and the immediate risk of colliding wild species with vehicles. Identifying the impacts of roads on wildlife can contribute to the establishment of actions that promote conservation. In Brazil, data on collisions between bats and vehicles are scarce and underestimated in the literature. We described bat roadkill from 2008 to 2019 on a stretch of the BR-040 highway, which crosses an area of Atlantic Forest. Roadkill species were identified and the sites with high collision frequencies were characterized. A total of 923 individuals of 57 species and five families of chiropterans were identified. Frugivore bats showed the largest number of affected individuals, with Artibeus lituratus, a common species in the study region, with the highest number of roadkills. The diet and foraging behaviour were the most likely factors explaining most of the bats killed on the highway. The highest roadkill rate was documented in the fall, and the critical points located nearby the APA Petrópolis and REBIO of Tinguá, environmental protection areas. We reinforce the need to mitigate these roadkills, ensuring that road systems, which constitute municipal, state and federal highways, are built to prevent major disturbance of habitat and displacement routes of these species. We believe in the need for mitigations, and considering the various species involved, we suggest speed bumps construction reducing the speed limit, installing bridges, and signaling the presence of wildlife, before the stretches identified as hotspots.

CFD-DEM Simulation of the Transport of Manganese Nodules in a Vertical Pipe

The present study aims to describe the characteristics of the hydraulic transport of manganese nodules in a vertical pipe. The solid–liquid two-phase flows were simulated using a numerical technique that combines the computational fluid dynamics (CFD) method and the discrete element method (DEM). Manganese nodules with diameters of 5.0 mm, 15.0 mm, and 30.0 mm were selected. The effects of the initial solid volume fraction and the initial mixture velocity were investigated. The results show that with increasing initial solid volume fraction, the liquid and solid velocities decrease but the total pressure drop over the pipe increases. Small particles are responsible for high particle collision frequency, which causes decreases in both the liquid velocity and the total pressure drop. Energy loss is aggravated by increasing the initial mixture velocity, manifesting in the increase of the total pressure drop. The retention ratio of manganese nodules varies inversely with the initial mixture velocity. A formula is proposed to describe the pressure drop due to the presence of solid particles and collisions.

Method of diagnosing broadband microwave reflection of plasma sheath

<sec>During the re-entry process of the aircraft, a layer of plasma sheath wrapping its surface will be generated, which will lead the communication quality to deteriorate and even interrupt, resulting in the phenomenon of “radio blackout”. The “radio blackout” problem has plagued the aerospace industry for many years. One of the very important reasons is the lack of awareness of the communication transmission environment caused by the limitations of plasma sheath measurements. Therefore, the realization of in-situ measurement of sheath parameters is the key to the research of the “radio blackout” problem of hypersonic vehicles.</sec><sec>In this work, a broadband microwave reflection method is presented and developed for diagnosing the reentry plasma sheath .The relationship between broadband microwave reflection data and plasma parameters is derived theoretically, and effective diagnostic frequency points are selected. Then, the plasma parameters are obtained by inversely using the reflection data of the selected effective frequency points to realize the simultaneous diagnosis and measurement of electron density and collision frequency.</sec><sec>This method makes up for the deficiency that the traditional reflectometer cannot diagnose high collision frequency plasma, and it can diagnose the parameter of the plasma sheath of the hypersonic vehicle in a complex environment.</sec><sec>A simulation model and an experimental platform are established, and the simulation analysis and ground experiment are carried out to verify the method. The electron density of the plasma is diagnosed by transmission diagnostics to provide a control for reflection experiments. The experimental results show that the difference between the two diagnostic results is small, which verifies the effectiveness of the method.</sec><sec>The method can realize the real-time diagnosis of plasma sheaths of re-entry vehicles or hypersonic vehicles under various flight conditions, and accumulate a large number of first-hand measurement data, which is of great scientific value in recognizing the characteristics of plasma sheaths comprehensively, objectively and accurately. It can also be used for the parameter input link of the adaptive measurement and control system environment. In addition, this method can also be used for real-time measurement of environment parameters of ground plasma jet and real-time monitoring of changes of plasma jet parameters without changing the jet shape.</sec>