Microplasma based on glow discharge could act as a non-contact gaseous electrode and has attracted much attention in both fundamental research and application. Herein, with microplasma as the anode,the electrodepositi...Microplasma based on glow discharge could act as a non-contact gaseous electrode and has attracted much attention in both fundamental research and application. Herein, with microplasma as the anode,the electrodeposition process of a series of metal and metal alloys in molten salt has been systemically studied. Four metal cations with different valence states, silver(Ag~+), nickel(Ni^(2+)), copper(Cu^(2+)), and iron(Fe^(3+)), could all be reduced on the solid cathode with high current efficiency and the corresponding metal products were of high purity. The electrodeposition of aluminum-lanthanum(Al-Ln) alloy on the aluminum cathode was also successfully carried out with microplasma as the anode, and the same alloy was obtained by using the conventional anode electrode. These results indicated that microplasma anode based on non-contact direct-current(DC) glow discharge is a promising electrode to be applied in molten salt electrolysis.展开更多
The problem of digital controlling of high frequency microplasma arc welding machine has been solved through Fujitsu 16-bits single-chip processor used.Digital welding power sources and their control systems,digital s...The problem of digital controlling of high frequency microplasma arc welding machine has been solved through Fujitsu 16-bits single-chip processor used.Digital welding power sources and their control systems,digital sequential control system,and digital man-machine interaction system were included in digital microplasma arc welding machine studied.Principles,which is about digital sequential control system,digital man-machine interaction system,digital controller and its interface,and controlling software program,were analyzed.It has been showed that full digitalization of high frequency microplasma arc welding machine was fulfilled,minimum welding current of the machine is 0.05A,and arc is stable and can been started unfailingly.展开更多
In order to demonstrate the modulation of terahertz wave propagation in atmospheric pressure microplasmas,in this work,the band structure and the transmission characteristics of a onedimensional collisional microplasm...In order to demonstrate the modulation of terahertz wave propagation in atmospheric pressure microplasmas,in this work,the band structure and the transmission characteristics of a onedimensional collisional microplasma photonic crystal are investigated,using the transfer matrix method.For a lattice constant of 150μm and a plasma width of 100μm,three stopbands of microplasma photonic crystal are observed,in a frequency range of 0.1-5 THz.Firstly,an increase in gas pressure leads to a decrease in the central frequency of the stopband.When the gas pressure increases from 50.5 k Pa to 202 k Pa,the transmission coefficient of the THz wave first increases and then decreases at high frequency,where the wave frequency is much greater than both the plasma frequency and the collision frequency.Secondly,it is interesting to find that the central frequency and the bandwidth of the first THz stopband remain almost unchanged for electron densities of less than 10^15 cm^-3,increasing significantly when the electron density increases up to 10^16 cm^-3.A central frequency shift of 110 GHz,and a bandgap broadening of 200 GHz in the first stopband are observed.In addition,an atmospheric pressure microplasma with the electron density of 1×10^15-6×10^15 cm^-3 is recommended for the modulation of THz wave propagation by plasma photonic crystals.展开更多
The microplasma oxidation process of LY 12 Al alloy in Na2SiO3-KOH-NaAL2 system has been studied. The voltage-time curve of oxidation process is changed with the variation of current ...The microplasma oxidation process of LY 12 Al alloy in Na2SiO3-KOH-NaAL2 system has been studied. The voltage-time curve of oxidation process is changed with the variation of current densities. The voltage breakdown and hardness of coating increase with increasing current density. The phase composition, morphologies, element and the distribution of ceramic coating are investigated by XRD, EPMA.展开更多
Low-temperature plasma is a green and high-efficiency technology for chemical warfare agent(CWA)decontamination.However,traditional plasma devices suffer from the problems of highpower composition and large power-supp...Low-temperature plasma is a green and high-efficiency technology for chemical warfare agent(CWA)decontamination.However,traditional plasma devices suffer from the problems of highpower composition and large power-supply size,which limit their practical applications.In this paper,a self-driven microplasma decontamination system,induced by a dielectric-dielectric rotary triboelectric nanogenerator(dd-r TENG),was innovatively proposed for the decontamination of CWA simulants.The microplasma was characterized via electrical measurements,optical emission spectra and ozone concentration detection.With an output voltage of-3460 V,the dd-r TENG can successfully excite microplasma in air.Reactive species,such as OH,O(1D),Hαand O3were detected.With input average power of 0.116 W,the decontamination rate of 2-chloroethyl ethyl sulfide reached 100%within 3 min of plasma treatment,while the decontamination rates of malathion and dimethyl methylphosphonate reached(65.92±1.65)%and(60.88±1.92)%after 7 min of plasma treatment,respectively.In addition,the decontamination rates gradually decreased with the increase in the simulant concentrations.Typical products were identified and analyzed.This study demonstrates the broad spectrum and feasibility of the dd-r TENG-microplasma for CWA elimination,which provides significant guidance for their practical applications in the future.展开更多
An atmospheric-pressure microplasma plume of diameter 10 μm is generated inside a long tube. The length of the microplasma plume reaches as much as 2 cm. First, with the assistance of an air dielectric barrier discha...An atmospheric-pressure microplasma plume of diameter 10 μm is generated inside a long tube. The length of the microplasma plume reaches as much as 2 cm. First, with the assistance of an air dielectric barrier discharge （DBD）, the ignition voltage of the microplasma decreases from 40 kV to 23.6 kV. Second, although the current density reaches as high as （1.2-7.6）× 10 4A cm-2, comparable to the current density in transient spark discharge, the microplasma plume is nonthermal. Third, it is interesting to observe that the amplitude of the discharge current in a positive cycle of applied voltage is much lower than that in a negative cycle of applied voltage. Fourth, the electron density measured by the Stark broadening of Ar spectral line 696.5 nm reaches as high as 3× 10 16 cm-3, which yields a conductivity of the microplasma column of around 48 S m-1. In addition, the propagation velocity of the microplasma plume, obtained from light signals at different axial positions, ranges from 1 × 10 5 m s-1 to 5× 10 5m s-1. A detailed analysis reveals that the surface charges deposited on the inner wall exert significant influence on the discharge behavior of the microplasma.展开更多
Human skin is the largest organ and also the main barrier that prevents foreign substances from entering the body.The surface properties of the skin are relevant for transdermal drug delivery and cosmetics.Yucatan mic...Human skin is the largest organ and also the main barrier that prevents foreign substances from entering the body.The surface properties of the skin are relevant for transdermal drug delivery and cosmetics.Yucatan micropig skin is used as a substitute for human skin.A microplasma electrode is used for surface modification of the skin epidermal layer of the Yucatan micropig.Microplasma dielectric barrier discharge has a thin dielectric as a barrier (~50 μm) and a frequency of 25 kHz.The surface properties of the epidermal layer were characterized by the measurement of the contact angle of the water droplet.The effects of different gases such as air,nitrogen,oxygen,helium or argon were compared.The change of the contact angle is temporal and it is returned to its initial state after several hours.Among the gases used for plasma ignition,oxygen and argon were the most effective for skin treatment.The distance of the skin from the electrode and the treatment time played a crucial roles in the increasing water contact angle.Changes of surface atomic concentration were determined by x-ray photoelectron spectroscopy.After microplasma treatment,the oxygen and nitrogen concentration increased at the skin surface.展开更多
Over the past years, great achievements have been made in the development of coating technologies for surface improvement of aluminum alloys. Despite these achievements, the role in the market strongly depends on the ...Over the past years, great achievements have been made in the development of coating technologies for surface improvement of aluminum alloys. Despite these achievements, the role in the market strongly depends on the ability of surface coating technology under technical and economic considerations to meet the increased demands for heavy tribological applications of aluminum alloys. Microplasma oxidation (MPO) technology has recently been studied as a novel and effective means to provide thick and hard ceramic coating with improved properties such as excellent load-bearing and wear resistance properties on aluminum alloys. The present work covers the evaluation of the performances of current single and duplex coatings combining MPO, physical vapor deposition (PVD), and plasma assisted chemical vapor deposition (PACVD) coatings on aluminum alloys. It suggests that the MPO coating is a promising candidate for design engineers to apply aluminum alloys to heavy load-bearing applications. The prospective future for the research on MPO coatings is introduced as well.展开更多
The spreading effect of atmospheric pressure microplasma jets(APμPJ)on the surface of materials will increase the etching area,and controlling the diameter of the jet can improve the precision of surface treatment.In...The spreading effect of atmospheric pressure microplasma jets(APμPJ)on the surface of materials will increase the etching area,and controlling the diameter of the jet can improve the precision of surface treatment.In this work,a two-dimensional axisymmetric simulation model is established to analyze the effect of nitrogen(N_(2))shielding gas on helium(He)from gas dynamics.In addition,by etching the polyethylene terephthalate fllm,the relationship between the etching effect and aerodynamic analysis is verifled.The simulation results are similar to the experimental results,indicating that N2 shielding gas has a focusing effect which is related to the N_(2)flow rate,distance difference between the inner and outer tubes,and outer tube nozzle diameter.It is hoped that the results of this work can provide a certain reference for the use of shielding gas to control the jet flow of APμPJ.展开更多
Microplasmas are very interesting due to their unique properties and achievable regimes maintained at atmospheric pressures. Due to the small scales, numerical modeling could contribute to the understanding of underly...Microplasmas are very interesting due to their unique properties and achievable regimes maintained at atmospheric pressures. Due to the small scales, numerical modeling could contribute to the understanding of underlying phenomena as it provides access to local parameters--and complements experimental global characteristics. A self-consistent formalism, applied to nanosecond pulsed atmospheric non-equilibrium helium plasmas, reveals that several successive discharges can persist as a result of a combined volume and dielectric surface effects. The valuable insights provided by the spatiotemporal simulation results show the critical importance of coupled gas and plasma dynamics--namely gas heating and electric field reversals.展开更多
Metal organic frameworks(MOFs) are a kind of promising materials in many applications,while the fast and controllable synthesis of MOFs is still challenging.Here,taking HKUST-1 as illustration,a microplasma electroche...Metal organic frameworks(MOFs) are a kind of promising materials in many applications,while the fast and controllable synthesis of MOFs is still challenging.Here,taking HKUST-1 as illustration,a microplasma electrochemistry(MIPEC) strategy was developed to accelerate the synthesis process of MOFs with micro-plasma acting as cathode.Treating the HKUST-1 precursor solution with micro-plasma cathode could not only transfer the electrons into the solution leading to the deprotonation effect,but also generate radical species to trigger and accelerate the nucleation and growth of MOFs at the plasmaliquid interface.Thus,uniform and nanosize MOFs could be prepared within minutes.The obtained MOFs show similar excellent uranium adsorption properties compared with those obtained by other method,with a highly adsorption capability of uranium with 550 mg/g in minutes.The novel MIPEC strategy developed in this work provides an alternative for controllable synthesis of MOFs,and especially has potential application in accelerating traditional organic synthesis.展开更多
The DC-driven atmospheric-pressure microplasma is generated in a helium gas flowing through the metal tube cathode and is brought into contact with the surface of the water with the immersed Pt anode.By adjusting the ...The DC-driven atmospheric-pressure microplasma is generated in a helium gas flowing through the metal tube cathode and is brought into contact with the surface of the water with the immersed Pt anode.By adjusting the gas flow,discharge current and gap distance,self-organized patterns are observed and varied sequentially from the homogeneous spot to the ring-like shape,distinct spot shape and the gearwheel shape on the water surface.The electrode temperature is measured and the gas temperature of the plasma discharge is calculated through the numericalfitting of the second positive system of the spectrum of N2 molecules.It is shown that the pattern transition is related to the electrode and gas temperatures of the plasma.Moreover,specific discretization features of the patterns are shown to appear at certain gas temperatures.展开更多
Precise and long-term electroanalysis at the single-cell level is crucial for the accurate diagnosis and monitoring of brain diseases.The reliable protection in areas outside the signal acquisition points at sharp ult...Precise and long-term electroanalysis at the single-cell level is crucial for the accurate diagnosis and monitoring of brain diseases.The reliable protection in areas outside the signal acquisition points at sharp ultramicroelectrode(UME)tips has a significant impact on the sensitivity,fidelity,and stability of intracellular neural signal recording.However,it is difficult for existing UMEs to achieve controllable exposure of the tip functional structure,which affects their ability to resist environmental interference and shield noise,resulting in unsatisfactory signal-to-noise ratio and signal fidelity of intracellular recordings.To address this issue,we chose a dense and electrochemically stable diamond-like carbon(DLC)film as the UME protection coating and developed a method to precisely control the exposed degree of the functional structure by directly fixed-point processing of the UME tip by the strong site-selectivity and good controllability of the atmospheric microplasma jet.By analyzing the interaction between the microplasma jet and the UME tip,as well as the changes in the removal length and microstructure of UME tips with processing time,the exposed tip length was precisely controlled down to the submicron scale.Biocompatibility experiments,electrochemical aging tests and real-time intracellular pH recording experiments have demonstrated that the DLC-UME with effective tip protection processed by microplasma jet has the potential to enable long-term detection of intracellular high-fidelity signals.展开更多
The past two decades have seen an exponential growth of interest in one of the least explored region of the electromagnetic spectrum, the terahertz （THz） frequency band, ranging from to 0.1 to 10 THz. Once only the ...The past two decades have seen an exponential growth of interest in one of the least explored region of the electromagnetic spectrum, the terahertz （THz） frequency band, ranging from to 0.1 to 10 THz. Once only the realm of astrophysicists studying the background radiation of the universe, THz waves have become little by little relevant in the most diverse fields, such as medical imaging, industrial inspection, remote sensing, fundamental science, and so on. Remarkably, THz wave radiation can be generated and detected by using ambient air as the source and the sensor. This is accomplished by creating plasma under the illumination of intense femtosecond laser fields. The integration of such a plasma source and sensor in THz time-domain techniques allows spectral measurements covering the whole THz gap （0.1 to 10 THz）, further increasing the impact of this scientific tool in the study of the four states of matter. In this review, the authors introduce a new paradigm for implementing THz plasma techniques. Specifically, we replaced the use of elongated plasmas, ranging from few mm to several cm, with sub-mm plasmas, which will be referred to as microplasmas, obtained by focusing ultrafast laser pulses with high numerical aperture optics （NA from 0.1 to 0.9）. The experimental study of the THz emission and detection from laser-induced plasmas of submillimeter size are presented. Regarding the microplasma source, one of the interesting phenomena is that the main direction of THz wave emission is almost orthogonal to the laser propagation direction, unlike that of elongated plasmas. Perhaps the most important achievement is the demonstra- tion that laser pulse energies lower than 1 μJ are sufficientto generate measurable THz pulses from ambient air, thus reducing the required laser energy requirement of two orders of magnitude compared to the state of art. This significant decrease in the required laser energy will make plasma-based THz techniques more accessible to the scientific community, as well as opening new potential industrial applications. Finally, experimental observations of THz radiation detection with microplasmas are also presented. As fully coherent detection was not achieved in this work, the results presented herein are to be considered a first step to understand the peculiarities involved in using the micro- plasma as a THz sensor.展开更多
目的比较混频超声波导入与封包复方利多卡因乳膏的镇痛效果。方法选择2021年9月至2022年4月在广西医科大学第一附属医院就诊的50例面部瘢痕为研究对象。将患者面部两侧随机分为观察组和对照组,分别行混频超声波导入或封包,对比疼痛评分...目的比较混频超声波导入与封包复方利多卡因乳膏的镇痛效果。方法选择2021年9月至2022年4月在广西医科大学第一附属医院就诊的50例面部瘢痕为研究对象。将患者面部两侧随机分为观察组和对照组,分别行混频超声波导入或封包,对比疼痛评分、不良反应、术中伴随症状、满意度。结果观察组术中VAS、术后5 min VAS、术中NRS、术中FPS-R的疼痛评分低于对照组,差异有统计学意义(P<0.05)。观察组不良反应率、术中伴随症状发生率低于对照组,差异无统计学意义(P>0.05);观察组满意度高于对照组,差异有统计学意义(P<0.05)。结论混频超声波导入复方利多卡因乳膏较局部封包在微等离子束治疗面部瘢痕中提高镇痛效果,未增加不良反应,提高患者满意度。展开更多
基金financially supported by the National Natural Science Foundation of China (Nos.21976104, 21906051)Young Elite Scientists Sponsorship Program (No.2021QNRC001) of China Association for Science and Technology。
文摘Microplasma based on glow discharge could act as a non-contact gaseous electrode and has attracted much attention in both fundamental research and application. Herein, with microplasma as the anode,the electrodeposition process of a series of metal and metal alloys in molten salt has been systemically studied. Four metal cations with different valence states, silver(Ag~+), nickel(Ni^(2+)), copper(Cu^(2+)), and iron(Fe^(3+)), could all be reduced on the solid cathode with high current efficiency and the corresponding metal products were of high purity. The electrodeposition of aluminum-lanthanum(Al-Ln) alloy on the aluminum cathode was also successfully carried out with microplasma as the anode, and the same alloy was obtained by using the conventional anode electrode. These results indicated that microplasma anode based on non-contact direct-current(DC) glow discharge is a promising electrode to be applied in molten salt electrolysis.
基金Foundation item:Key Basic Research Project of Science and Technology Commission of Shanghai(10JC1406000)
文摘The problem of digital controlling of high frequency microplasma arc welding machine has been solved through Fujitsu 16-bits single-chip processor used.Digital welding power sources and their control systems,digital sequential control system,and digital man-machine interaction system were included in digital microplasma arc welding machine studied.Principles,which is about digital sequential control system,digital man-machine interaction system,digital controller and its interface,and controlling software program,were analyzed.It has been showed that full digitalization of high frequency microplasma arc welding machine was fulfilled,minimum welding current of the machine is 0.05A,and arc is stable and can been started unfailingly.
基金supported by National Natural Science Foundation of China(No.51977110)。
文摘In order to demonstrate the modulation of terahertz wave propagation in atmospheric pressure microplasmas,in this work,the band structure and the transmission characteristics of a onedimensional collisional microplasma photonic crystal are investigated,using the transfer matrix method.For a lattice constant of 150μm and a plasma width of 100μm,three stopbands of microplasma photonic crystal are observed,in a frequency range of 0.1-5 THz.Firstly,an increase in gas pressure leads to a decrease in the central frequency of the stopband.When the gas pressure increases from 50.5 k Pa to 202 k Pa,the transmission coefficient of the THz wave first increases and then decreases at high frequency,where the wave frequency is much greater than both the plasma frequency and the collision frequency.Secondly,it is interesting to find that the central frequency and the bandwidth of the first THz stopband remain almost unchanged for electron densities of less than 10^15 cm^-3,increasing significantly when the electron density increases up to 10^16 cm^-3.A central frequency shift of 110 GHz,and a bandgap broadening of 200 GHz in the first stopband are observed.In addition,an atmospheric pressure microplasma with the electron density of 1×10^15-6×10^15 cm^-3 is recommended for the modulation of THz wave propagation by plasma photonic crystals.
文摘The microplasma oxidation process of LY 12 Al alloy in Na2SiO3-KOH-NaAL2 system has been studied. The voltage-time curve of oxidation process is changed with the variation of current densities. The voltage breakdown and hardness of coating increase with increasing current density. The phase composition, morphologies, element and the distribution of ceramic coating are investigated by XRD, EPMA.
基金supported by National Natural Science Foundation of China(No.51877205)Fundamental Research Funds for the Central Universities(No.buct201906)+1 种基金the State Key Laboratory of NBC Protection for Civilian(No.SKLNBC2021-0X)Beijing Nova Program(No.2022015)。
文摘Low-temperature plasma is a green and high-efficiency technology for chemical warfare agent(CWA)decontamination.However,traditional plasma devices suffer from the problems of highpower composition and large power-supply size,which limit their practical applications.In this paper,a self-driven microplasma decontamination system,induced by a dielectric-dielectric rotary triboelectric nanogenerator(dd-r TENG),was innovatively proposed for the decontamination of CWA simulants.The microplasma was characterized via electrical measurements,optical emission spectra and ozone concentration detection.With an output voltage of-3460 V,the dd-r TENG can successfully excite microplasma in air.Reactive species,such as OH,O(1D),Hαand O3were detected.With input average power of 0.116 W,the decontamination rate of 2-chloroethyl ethyl sulfide reached 100%within 3 min of plasma treatment,while the decontamination rates of malathion and dimethyl methylphosphonate reached(65.92±1.65)%and(60.88±1.92)%after 7 min of plasma treatment,respectively.In addition,the decontamination rates gradually decreased with the increase in the simulant concentrations.Typical products were identified and analyzed.This study demonstrates the broad spectrum and feasibility of the dd-r TENG-microplasma for CWA elimination,which provides significant guidance for their practical applications in the future.
基金partially supported by National Natural Science Foundation of China (No. 51607090)the Natural Science Foundation of Jiangsu Province (No. BK20160796)+2 种基金the Delta Research and Educational Foundation (No. DREG2017008)Fundamental Research Funds for the Central Universities (No. XCA17003–03)financial support from the China Scholarship Council
文摘An atmospheric-pressure microplasma plume of diameter 10 μm is generated inside a long tube. The length of the microplasma plume reaches as much as 2 cm. First, with the assistance of an air dielectric barrier discharge （DBD）, the ignition voltage of the microplasma decreases from 40 kV to 23.6 kV. Second, although the current density reaches as high as （1.2-7.6）× 10 4A cm-2, comparable to the current density in transient spark discharge, the microplasma plume is nonthermal. Third, it is interesting to observe that the amplitude of the discharge current in a positive cycle of applied voltage is much lower than that in a negative cycle of applied voltage. Fourth, the electron density measured by the Stark broadening of Ar spectral line 696.5 nm reaches as high as 3× 10 16 cm-3, which yields a conductivity of the microplasma column of around 48 S m-1. In addition, the propagation velocity of the microplasma plume, obtained from light signals at different axial positions, ranges from 1 × 10 5 m s-1 to 5× 10 5m s-1. A detailed analysis reveals that the surface charges deposited on the inner wall exert significant influence on the discharge behavior of the microplasma.
文摘Human skin is the largest organ and also the main barrier that prevents foreign substances from entering the body.The surface properties of the skin are relevant for transdermal drug delivery and cosmetics.Yucatan micropig skin is used as a substitute for human skin.A microplasma electrode is used for surface modification of the skin epidermal layer of the Yucatan micropig.Microplasma dielectric barrier discharge has a thin dielectric as a barrier (~50 μm) and a frequency of 25 kHz.The surface properties of the epidermal layer were characterized by the measurement of the contact angle of the water droplet.The effects of different gases such as air,nitrogen,oxygen,helium or argon were compared.The change of the contact angle is temporal and it is returned to its initial state after several hours.Among the gases used for plasma ignition,oxygen and argon were the most effective for skin treatment.The distance of the skin from the electrode and the treatment time played a crucial roles in the increasing water contact angle.Changes of surface atomic concentration were determined by x-ray photoelectron spectroscopy.After microplasma treatment,the oxygen and nitrogen concentration increased at the skin surface.
文摘Over the past years, great achievements have been made in the development of coating technologies for surface improvement of aluminum alloys. Despite these achievements, the role in the market strongly depends on the ability of surface coating technology under technical and economic considerations to meet the increased demands for heavy tribological applications of aluminum alloys. Microplasma oxidation (MPO) technology has recently been studied as a novel and effective means to provide thick and hard ceramic coating with improved properties such as excellent load-bearing and wear resistance properties on aluminum alloys. The present work covers the evaluation of the performances of current single and duplex coatings combining MPO, physical vapor deposition (PVD), and plasma assisted chemical vapor deposition (PACVD) coatings on aluminum alloys. It suggests that the MPO coating is a promising candidate for design engineers to apply aluminum alloys to heavy load-bearing applications. The prospective future for the research on MPO coatings is introduced as well.
基金supported by National Natural Science Foundation of China(No.51905002)Anhui Provincial Natural Science Foundation(Nos.2008085QE230,2108085ME174)+2 种基金Open Project of Key Laboratory of Green Fabrication and Surface Technology of Advanced Metal Materials(No.GFST2021KF06)Open Project of Anhui Province Key Laboratory of Special and Heavy Load Robot(No.TZJQRO03-2021)Open Project of Anhui Province Engineering Laboratory of Intelligent Demolition Equipment(No.APELIDE2021B001)。
文摘The spreading effect of atmospheric pressure microplasma jets(APμPJ)on the surface of materials will increase the etching area,and controlling the diameter of the jet can improve the precision of surface treatment.In this work,a two-dimensional axisymmetric simulation model is established to analyze the effect of nitrogen(N_(2))shielding gas on helium(He)from gas dynamics.In addition,by etching the polyethylene terephthalate fllm,the relationship between the etching effect and aerodynamic analysis is verifled.The simulation results are similar to the experimental results,indicating that N2 shielding gas has a focusing effect which is related to the N_(2)flow rate,distance difference between the inner and outer tubes,and outer tube nozzle diameter.It is hoped that the results of this work can provide a certain reference for the use of shielding gas to control the jet flow of APμPJ.
基金supported by the Natural Sciences and Engineering Research Council of Canada(NSERC)-Discovery Grant(No.342369)
文摘Microplasmas are very interesting due to their unique properties and achievable regimes maintained at atmospheric pressures. Due to the small scales, numerical modeling could contribute to the understanding of underlying phenomena as it provides access to local parameters--and complements experimental global characteristics. A self-consistent formalism, applied to nanosecond pulsed atmospheric non-equilibrium helium plasmas, reveals that several successive discharges can persist as a result of a combined volume and dielectric surface effects. The valuable insights provided by the spatiotemporal simulation results show the critical importance of coupled gas and plasma dynamics--namely gas heating and electric field reversals.
基金the National Natural Science Foundation of China(Nos.21976104 and 21775087)。
文摘Metal organic frameworks(MOFs) are a kind of promising materials in many applications,while the fast and controllable synthesis of MOFs is still challenging.Here,taking HKUST-1 as illustration,a microplasma electrochemistry(MIPEC) strategy was developed to accelerate the synthesis process of MOFs with micro-plasma acting as cathode.Treating the HKUST-1 precursor solution with micro-plasma cathode could not only transfer the electrons into the solution leading to the deprotonation effect,but also generate radical species to trigger and accelerate the nucleation and growth of MOFs at the plasmaliquid interface.Thus,uniform and nanosize MOFs could be prepared within minutes.The obtained MOFs show similar excellent uranium adsorption properties compared with those obtained by other method,with a highly adsorption capability of uranium with 550 mg/g in minutes.The novel MIPEC strategy developed in this work provides an alternative for controllable synthesis of MOFs,and especially has potential application in accelerating traditional organic synthesis.
基金supported by National Natural Science Foundation of China(No.11675109)Biomedical Engineering Cross Research Foundation of Shanghai Jiao Tong University(YG2016MS12)the Australian Research Council for partial support。
文摘The DC-driven atmospheric-pressure microplasma is generated in a helium gas flowing through the metal tube cathode and is brought into contact with the surface of the water with the immersed Pt anode.By adjusting the gas flow,discharge current and gap distance,self-organized patterns are observed and varied sequentially from the homogeneous spot to the ring-like shape,distinct spot shape and the gearwheel shape on the water surface.The electrode temperature is measured and the gas temperature of the plasma discharge is calculated through the numericalfitting of the second positive system of the spectrum of N2 molecules.It is shown that the pattern transition is related to the electrode and gas temperatures of the plasma.Moreover,specific discretization features of the patterns are shown to appear at certain gas temperatures.
基金supported by the National Key R&D Program of China under grant 2022YFF120301the Fundamental Research Funds for the Central Universities,the Strategic Priority Research Program of Chinese Academy of Sciences(Grant Nos.XDA25040100,XDA25040200 and XDA25040300)+4 种基金the National Natural Science Foundation of China(No.42127807-03)Project supported by Shanghai Municipal Science and Technology Major Project(2021SHZDZX)Shanghai Pilot Program for Basic Research-Shanghai Jiao Tong University(No.21TQ1400203)the Oceanic Interdisciplinary Program of Shanghai Jiao Tong University(No.SL2023ZD205)SJTU Trans-med Award(No.21X010301627).
文摘Precise and long-term electroanalysis at the single-cell level is crucial for the accurate diagnosis and monitoring of brain diseases.The reliable protection in areas outside the signal acquisition points at sharp ultramicroelectrode(UME)tips has a significant impact on the sensitivity,fidelity,and stability of intracellular neural signal recording.However,it is difficult for existing UMEs to achieve controllable exposure of the tip functional structure,which affects their ability to resist environmental interference and shield noise,resulting in unsatisfactory signal-to-noise ratio and signal fidelity of intracellular recordings.To address this issue,we chose a dense and electrochemically stable diamond-like carbon(DLC)film as the UME protection coating and developed a method to precisely control the exposed degree of the functional structure by directly fixed-point processing of the UME tip by the strong site-selectivity and good controllability of the atmospheric microplasma jet.By analyzing the interaction between the microplasma jet and the UME tip,as well as the changes in the removal length and microstructure of UME tips with processing time,the exposed tip length was precisely controlled down to the submicron scale.Biocompatibility experiments,electrochemical aging tests and real-time intracellular pH recording experiments have demonstrated that the DLC-UME with effective tip protection processed by microplasma jet has the potential to enable long-term detection of intracellular high-fidelity signals.
文摘The past two decades have seen an exponential growth of interest in one of the least explored region of the electromagnetic spectrum, the terahertz （THz） frequency band, ranging from to 0.1 to 10 THz. Once only the realm of astrophysicists studying the background radiation of the universe, THz waves have become little by little relevant in the most diverse fields, such as medical imaging, industrial inspection, remote sensing, fundamental science, and so on. Remarkably, THz wave radiation can be generated and detected by using ambient air as the source and the sensor. This is accomplished by creating plasma under the illumination of intense femtosecond laser fields. The integration of such a plasma source and sensor in THz time-domain techniques allows spectral measurements covering the whole THz gap （0.1 to 10 THz）, further increasing the impact of this scientific tool in the study of the four states of matter. In this review, the authors introduce a new paradigm for implementing THz plasma techniques. Specifically, we replaced the use of elongated plasmas, ranging from few mm to several cm, with sub-mm plasmas, which will be referred to as microplasmas, obtained by focusing ultrafast laser pulses with high numerical aperture optics （NA from 0.1 to 0.9）. The experimental study of the THz emission and detection from laser-induced plasmas of submillimeter size are presented. Regarding the microplasma source, one of the interesting phenomena is that the main direction of THz wave emission is almost orthogonal to the laser propagation direction, unlike that of elongated plasmas. Perhaps the most important achievement is the demonstra- tion that laser pulse energies lower than 1 μJ are sufficientto generate measurable THz pulses from ambient air, thus reducing the required laser energy requirement of two orders of magnitude compared to the state of art. This significant decrease in the required laser energy will make plasma-based THz techniques more accessible to the scientific community, as well as opening new potential industrial applications. Finally, experimental observations of THz radiation detection with microplasmas are also presented. As fully coherent detection was not achieved in this work, the results presented herein are to be considered a first step to understand the peculiarities involved in using the micro- plasma as a THz sensor.
文摘目的比较混频超声波导入与封包复方利多卡因乳膏的镇痛效果。方法选择2021年9月至2022年4月在广西医科大学第一附属医院就诊的50例面部瘢痕为研究对象。将患者面部两侧随机分为观察组和对照组,分别行混频超声波导入或封包,对比疼痛评分、不良反应、术中伴随症状、满意度。结果观察组术中VAS、术后5 min VAS、术中NRS、术中FPS-R的疼痛评分低于对照组,差异有统计学意义(P<0.05)。观察组不良反应率、术中伴随症状发生率低于对照组,差异无统计学意义(P>0.05);观察组满意度高于对照组,差异有统计学意义(P<0.05)。结论混频超声波导入复方利多卡因乳膏较局部封包在微等离子束治疗面部瘢痕中提高镇痛效果,未增加不良反应,提高患者满意度。
