The interfacial properties of Schottky contacts crucially affect the performance of power devices. While a few studies have explored the impact of fluorine on Schottky contacts, a comprehensive theoretical explanation...The interfacial properties of Schottky contacts crucially affect the performance of power devices. While a few studies have explored the impact of fluorine on Schottky contacts, a comprehensive theoretical explanation supported by experimental evidence remains lacking. This work investigates the effects of fluorine incorporation and electrothermal annealing(ETA) on the current transport process at Ni/β-Ga_(2)O_(3) Schottky contacts. X-ray photoelectron spectroscopy and first-principles calculations confirm the presence of fluorine substitutions for oxygen and oxygen vacancies and their lowering effect on the Schottky barrier heights. Additionally, accurate electrothermal hybrid TCAD simulations validates the extremely short-duration high temperatures(683 K) induced by ETA, which facilitates lattice rearrangement and reduces interface trap states. The interface trap states are quantitatively resolved through frequency-dependent conductance technique, showing the trap density(DT)reduction from(0.88-2.48) × 10^(11) cm^(-2)·eV^(-1) to(0.46-2.09) × 10^(11) cm^(-2)·eV^(-1). This investigation offers critical insights into the β-Ga_(2)O_(3) contacts with the collaborative treatment and solids the promotion of high-performance β-Ga_(2)O_(3) power devices.展开更多
Cold plasma generated by dielectric barrier discharge （DBD） at atmospheric pressure was adopted for preparation of commercial TiO2 Degussa P25 supported Au catalysts （Au/P25- P） with the assistance of the depositi...Cold plasma generated by dielectric barrier discharge （DBD） at atmospheric pressure was adopted for preparation of commercial TiO2 Degussa P25 supported Au catalysts （Au/P25- P） with the assistance of the deposition-precipitation procedure. The influences of the plasma reduction time and calcination on the performance of the Au/P25-P catalysts were investigated. CO oxidation was performed to investigate the catalytic activity of the Au/P25 catalysts. The results show that DBD cold plasma for the fabrication of Au/P25-P catalysts is a fast process, and Au/P25-P （4 min） exhibited the highest CO oxidation activity due to the complete reduction of Au compounds and less consumption of oxygen vacancies. In order to form more oxygen vacancies active species, Au/P25-P was calcined to obtain Au/P25-PC catalysts. Interestingly, Au/P25- PC exhibited the highest activity for CO oxidation among the Au/P25 samples. The results of transmission electron microscopy （TEM） indicated that the smaller size and high distribution of Au nanoparticles are the mean reasons for a high performance of Au/P25-PC. Atmospheric- pressure DBD cold plasma was proved to be of great efficiency in preparing high performance supported Au catalysts.展开更多
Modification of poly(tetrafluoroethylene)(PTFE) films with 2-methacryloyloxyethyl phosphorylcholine(MPC) was performed by low-temperature plasma treatment and grafting polymerization.Surface properties of PTFE were ch...Modification of poly(tetrafluoroethylene)(PTFE) films with 2-methacryloyloxyethyl phosphorylcholine(MPC) was performed by low-temperature plasma treatment and grafting polymerization.Surface properties of PTFE were characterized by attenuated total reflectance Fourier transform infrared(ATR-FTIR) spectra,X-ray photoelectron spectroscopy(XPS) ,and static contact angle.The results show that MPC has been grafted onto PTFE film surface successfully.Contact angle for the modified PTFE films in the water decreased from 108°to 58.25°,while surface energy increased from 17.52 mN/m to 45.47 mN/m.The effects of plasma treatment time,monomer concentration and grafting time on degree of grafting were determined.In the meanwhile,blood compatibility of the PTFE films was studied by checking thrombogenic time of blood plasma.展开更多
Knowledge of plasma composition is very important for various plasma applications and prediction of plasma properties. We use the Saha equation and Debye length equation to calculate the non-local thermodynamic-equili...Knowledge of plasma composition is very important for various plasma applications and prediction of plasma properties. We use the Saha equation and Debye length equation to calculate the non-local thermodynamic-equilibrium plasma composition. It has been shown that the model to 2T with T representing the temperature （electron temperature and heavy-particle temperature） described by Chen and Han [J. Phys. D 32 （1999）1711] can be applied for a mixture of gases, where each atomic species has its own temperature, but the model to 4T is more general because it can be applicable to temperatures distant enough of the heavy particles. This can occur in a plasma composed of big- or macro-molecules. The electron temperature Te varies in the range 8000＊20000K at atmospheric pressure.展开更多
Efficient removal of pollutant formaldehyde(HCHO) at room temperature using transition-metal oxides remains a huge challenge to date. Manganese oxide can oxidize formaldehyde, however, how to control the valence state...Efficient removal of pollutant formaldehyde(HCHO) at room temperature using transition-metal oxides remains a huge challenge to date. Manganese oxide can oxidize formaldehyde, however, how to control the valence states of manganese is the key to further improve the removal efficiency. We have successfully prepared porous manganese oxide nanowires(Mn OxNWs) with large surface area and multiple valence states of manganese using simple electrospinning followed by thermal calcination and potassium permanganate solution post-treatment(C/S process). The contents of trivalent and tetravalent manganese increased significantly after C/S process. Moreover, the composition of silver oxide coated silver nanowires(Ag@Ag_(2) O NWs) is realized by assistance with oxygen plasma, which further enhanced high valence manganese. The formaldehyde removal efficiency by Ag@Ag_(2) O–Mn Oxcomposite nanowires can reach 93.7%. The high-efficient catalytic activity is confirmed to attribute to the higher surface area of composite nanowires, the high-valence manganese and the silver oxide for oxidation of formaldehyde.展开更多
Methane conversion in the presence of oxygen under low-temperature radio frequency （RF） plasma was investigated.The experiment results indicated that the following four factors,i.e.,discharge voltage,discharge area,...Methane conversion in the presence of oxygen under low-temperature radio frequency （RF） plasma was investigated.The experiment results indicated that the following four factors,i.e.,discharge voltage,discharge area,O2/CH4 molar ratio and total gas flowrate,affected remarkably the reaction performance.The optimum reaction conditions of methane conversion in the presence of O2 under RF plasma are as follows：discharge voltage 1050 V,discharge area 989.1mm 2,O2/CH4 molar ratio 1/10 and total gas flowrate 200 ml/min.A methane conversion of 91% could be reached under the optimum conditions.Oxygen is good for the breaking of C-H bonds and also acts as a sort of thinner.According to the low-temperature plasma characteristics,the macroscopic kinetics model of methane conversion in the presence of O2 under radio frequency plasma was studied.展开更多
The influence on the effectiveness of sterilization by low-temperature plasma sterilizer CASP-80A was investigated so as to provide a theoretical basis for reducing medical costs and achieving ideal sterilization effe...The influence on the effectiveness of sterilization by low-temperature plasma sterilizer CASP-80A was investigated so as to provide a theoretical basis for reducing medical costs and achieving ideal sterilization effectiveness. To conduct the on-site simulation test, a clinical material sterilization test and a test of the influence of organic substance were conducted, the former by using the representative of Bacillus Stearothermophilus, preparing the bacteria-contaminated carrier through polytetrafluoroethylene （PTFE） simulated hose endoscopes, and the latter by using calf serum as the influence factor of the organic substance. The results show that the CASP-80A low-temperature plasma sterilizer could achieve effective sterilization by either the short-cycle or the long-cycle sterilization method depending on different materials, apparatus, and extent of contamination. The organic substances could influence the effectiveness of sterilization by the low-temperature plasma （H2O2） sterilizer.展开更多
The plasma catalytic degradation of o-xylene in simulated air was improved by loading low amounts of Pt,Pd,or Au onto Co_(3)O_(4).At room temperature,o-xylene conversion and CO_(x)selectivity using a0.1 wt%Pt/Co_(3)O_...The plasma catalytic degradation of o-xylene in simulated air was improved by loading low amounts of Pt,Pd,or Au onto Co_(3)O_(4).At room temperature,o-xylene conversion and CO_(x)selectivity using a0.1 wt%Pt/Co_(3)O_(4)catalyst reached 98.9%and 80%,and the energy efficiency was at the top level in comparison with values in the literature.A stable o-xylene degradation performance could be obtained by online regenerating the heat-insulated reactor with a high energy density.After characterization,it was found that the loading of nanosized Pt not only increased the Co^(3+)/Co^(2+)ratio,where the Co^(3+)benefitted the formation of reactive oxygen species,but also conduced Pt^(0)to oxygen activation,resulting in effective promotion of complete o-xylene oxidation.Operando plasma diffuse reflectance infrared Fourier transform spectroscopy demonstrated the complete o-xylene oxidation and proved that Pt played a key role in the complete oxidation of o-xylene.展开更多
A novel plasma torch nitriding technology was applied for the first time to improve the surface properties of M2 high-speed steel by adjusting different experimental parameters.The nitrogen content,precipitate,microst...A novel plasma torch nitriding technology was applied for the first time to improve the surface properties of M2 high-speed steel by adjusting different experimental parameters.The nitrogen content,precipitate,microstructure,mechanical property,and corrosion resistance of the nitrided layer were comprehensively analyzed using an ONH analyzer,scanning electron microscope(SEM),micro-area X-ray diffractometer,transmission electron microscope(TEM),Vickers microhardness tester,high-temperature wear tester,3D profilometer,tensile testing machine,and electrochemical workstation.The research results show that the novel plasma torch nitriding technology can achieve synergistic strengthening of nitrogen,carbon,and alloying element solid solution,precipitation strengthening,and martensitic structure on the surface of M2 high-speed steel.The nitrogen content on the specimen surface increased up to 0.17%,while the size and area of carbides were reduced by 89%and 86%,respectively,indicating a transformation towards fine nitrogen-rich precipitates.Compared to the original M2 steel,the nitrided specimens exhibited significant improvements in overall performance.The hardness increased from 228 HV_(0.2)to a maximum of 795 HV_(0.2),the wear coefficient decreased from a maximum of 0.8 to 0.49,the tensile strength increased from 753 MPa to a maximum of 934 MPa,and the corrosion current density decreased from 1.2×10^(−5)to a minimum of 1.9×10^(−6)A/cm^(2).展开更多
The production of medical waste(MW)is a growing concern,particularly in light of the increasing annual generation and the exacerbating effects of the COVID-19 pandemic.Traditional techniques such as incineration and l...The production of medical waste(MW)is a growing concern,particularly in light of the increasing annual generation and the exacerbating effects of the COVID-19 pandemic.Traditional techniques such as incineration and landfilling present significant limitations.In this study,a self-designed 50 kW arc plasma reactor was employed to conduct gasification experiments on nitrile-butadiene rubber(NBR)which served as a model of MWand a mixture of NBR/SiO_(2) which served as a model of glass-containing MW,using CO_(2)as the working gas.The CO_(2)thermal plasma gasification process not only ensures the safe and efficient disposal of MW,but also facilitates its effective conversion into H_(2)and CO,achieving a carbon conversion efficiency of 94.52%.The yields of H2 and CO reached 98.52%and 81.83%,respectively,and the specific energy consumption was as low as 3.55 kW·h·kg^(-1).Furthermore,the addition of SiO_(2) was found to inhibit the gasification of NBR and cause damage to the reactor.Therefore,it is recommended that glass waste should be removed prior to the treatment of MW.The CO_(2)thermal plasma gasification technology can not only eliminate environmental and health risks posed by MW,but also convert it into syngas for further utilization.This provides a promising approach to the harmless and resource disposal of MW,while also contributing to the comprehensive utilization of greenhouse gases.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 62174019, 52302046, L2424216)the Guangdong Basic and Applied Basic Research Foundation (Grant No. 2024A1515012139)+2 种基金the Major Program (JD) of Hubei Province (Grant No. 2023BAA009)the Knowledge Innovation Program of Wuhan-Shuguang Project (Grant No. 2023010201020262)the Basic Research Program of Jiangsu (Grant No. BK20230268)。
文摘The interfacial properties of Schottky contacts crucially affect the performance of power devices. While a few studies have explored the impact of fluorine on Schottky contacts, a comprehensive theoretical explanation supported by experimental evidence remains lacking. This work investigates the effects of fluorine incorporation and electrothermal annealing(ETA) on the current transport process at Ni/β-Ga_(2)O_(3) Schottky contacts. X-ray photoelectron spectroscopy and first-principles calculations confirm the presence of fluorine substitutions for oxygen and oxygen vacancies and their lowering effect on the Schottky barrier heights. Additionally, accurate electrothermal hybrid TCAD simulations validates the extremely short-duration high temperatures(683 K) induced by ETA, which facilitates lattice rearrangement and reduces interface trap states. The interface trap states are quantitatively resolved through frequency-dependent conductance technique, showing the trap density(DT)reduction from(0.88-2.48) × 10^(11) cm^(-2)·eV^(-1) to(0.46-2.09) × 10^(11) cm^(-2)·eV^(-1). This investigation offers critical insights into the β-Ga_(2)O_(3) contacts with the collaborative treatment and solids the promotion of high-performance β-Ga_(2)O_(3) power devices.
基金supported by National Natural Science Foundation of China(Nos.11505019,21173028)the Science and Technology Research Project of Liaoning Provincial Education Department(No.L2013464)+1 种基金the Scientific Research Foundation for the Doctor of Liaoning Province(No.20131004)the Dalian Jinzhou New District Science and Technology Plan Project(No.KJCX-ZTPY-2014-0001)
文摘Cold plasma generated by dielectric barrier discharge （DBD） at atmospheric pressure was adopted for preparation of commercial TiO2 Degussa P25 supported Au catalysts （Au/P25- P） with the assistance of the deposition-precipitation procedure. The influences of the plasma reduction time and calcination on the performance of the Au/P25-P catalysts were investigated. CO oxidation was performed to investigate the catalytic activity of the Au/P25 catalysts. The results show that DBD cold plasma for the fabrication of Au/P25-P catalysts is a fast process, and Au/P25-P （4 min） exhibited the highest CO oxidation activity due to the complete reduction of Au compounds and less consumption of oxygen vacancies. In order to form more oxygen vacancies active species, Au/P25-P was calcined to obtain Au/P25-PC catalysts. Interestingly, Au/P25- PC exhibited the highest activity for CO oxidation among the Au/P25 samples. The results of transmission electron microscopy （TEM） indicated that the smaller size and high distribution of Au nanoparticles are the mean reasons for a high performance of Au/P25-PC. Atmospheric- pressure DBD cold plasma was proved to be of great efficiency in preparing high performance supported Au catalysts.
文摘Modification of poly(tetrafluoroethylene)(PTFE) films with 2-methacryloyloxyethyl phosphorylcholine(MPC) was performed by low-temperature plasma treatment and grafting polymerization.Surface properties of PTFE were characterized by attenuated total reflectance Fourier transform infrared(ATR-FTIR) spectra,X-ray photoelectron spectroscopy(XPS) ,and static contact angle.The results show that MPC has been grafted onto PTFE film surface successfully.Contact angle for the modified PTFE films in the water decreased from 108°to 58.25°,while surface energy increased from 17.52 mN/m to 45.47 mN/m.The effects of plasma treatment time,monomer concentration and grafting time on degree of grafting were determined.In the meanwhile,blood compatibility of the PTFE films was studied by checking thrombogenic time of blood plasma.
文摘Knowledge of plasma composition is very important for various plasma applications and prediction of plasma properties. We use the Saha equation and Debye length equation to calculate the non-local thermodynamic-equilibrium plasma composition. It has been shown that the model to 2T with T representing the temperature （electron temperature and heavy-particle temperature） described by Chen and Han [J. Phys. D 32 （1999）1711] can be applied for a mixture of gases, where each atomic species has its own temperature, but the model to 4T is more general because it can be applicable to temperatures distant enough of the heavy particles. This can occur in a plasma composed of big- or macro-molecules. The electron temperature Te varies in the range 8000＊20000K at atmospheric pressure.
基金financially supported by the National Natural Science Foundation of China (Grant No.51975151)the Heilongjiang Provincial Natural Science Foundation of China (Grant No.LH2019E041)Heilongjiang Touyan Team。
文摘Efficient removal of pollutant formaldehyde(HCHO) at room temperature using transition-metal oxides remains a huge challenge to date. Manganese oxide can oxidize formaldehyde, however, how to control the valence states of manganese is the key to further improve the removal efficiency. We have successfully prepared porous manganese oxide nanowires(Mn OxNWs) with large surface area and multiple valence states of manganese using simple electrospinning followed by thermal calcination and potassium permanganate solution post-treatment(C/S process). The contents of trivalent and tetravalent manganese increased significantly after C/S process. Moreover, the composition of silver oxide coated silver nanowires(Ag@Ag_(2) O NWs) is realized by assistance with oxygen plasma, which further enhanced high valence manganese. The formaldehyde removal efficiency by Ag@Ag_(2) O–Mn Oxcomposite nanowires can reach 93.7%. The high-efficient catalytic activity is confirmed to attribute to the higher surface area of composite nanowires, the high-valence manganese and the silver oxide for oxidation of formaldehyde.
文摘Methane conversion in the presence of oxygen under low-temperature radio frequency （RF） plasma was investigated.The experiment results indicated that the following four factors,i.e.,discharge voltage,discharge area,O2/CH4 molar ratio and total gas flowrate,affected remarkably the reaction performance.The optimum reaction conditions of methane conversion in the presence of O2 under RF plasma are as follows：discharge voltage 1050 V,discharge area 989.1mm 2,O2/CH4 molar ratio 1/10 and total gas flowrate 200 ml/min.A methane conversion of 91% could be reached under the optimum conditions.Oxygen is good for the breaking of C-H bonds and also acts as a sort of thinner.According to the low-temperature plasma characteristics,the macroscopic kinetics model of methane conversion in the presence of O2 under radio frequency plasma was studied.
文摘The influence on the effectiveness of sterilization by low-temperature plasma sterilizer CASP-80A was investigated so as to provide a theoretical basis for reducing medical costs and achieving ideal sterilization effectiveness. To conduct the on-site simulation test, a clinical material sterilization test and a test of the influence of organic substance were conducted, the former by using the representative of Bacillus Stearothermophilus, preparing the bacteria-contaminated carrier through polytetrafluoroethylene （PTFE） simulated hose endoscopes, and the latter by using calf serum as the influence factor of the organic substance. The results show that the CASP-80A low-temperature plasma sterilizer could achieve effective sterilization by either the short-cycle or the long-cycle sterilization method depending on different materials, apparatus, and extent of contamination. The organic substances could influence the effectiveness of sterilization by the low-temperature plasma （H2O2） sterilizer.
基金supported by National Natural Science Foundation of China(No.12075037)Research and Application Service Platform Project of API Manufacturing Environmental Protection and Safety Technology in China(No.2020-0107-3-1)。
文摘The plasma catalytic degradation of o-xylene in simulated air was improved by loading low amounts of Pt,Pd,or Au onto Co_(3)O_(4).At room temperature,o-xylene conversion and CO_(x)selectivity using a0.1 wt%Pt/Co_(3)O_(4)catalyst reached 98.9%and 80%,and the energy efficiency was at the top level in comparison with values in the literature.A stable o-xylene degradation performance could be obtained by online regenerating the heat-insulated reactor with a high energy density.After characterization,it was found that the loading of nanosized Pt not only increased the Co^(3+)/Co^(2+)ratio,where the Co^(3+)benefitted the formation of reactive oxygen species,but also conduced Pt^(0)to oxygen activation,resulting in effective promotion of complete o-xylene oxidation.Operando plasma diffuse reflectance infrared Fourier transform spectroscopy demonstrated the complete o-xylene oxidation and proved that Pt played a key role in the complete oxidation of o-xylene.
基金supported by the National Science and Technology Major Project of China(No.HT-J2019-V-0023-0140)Open Project of State Key Laboratory of Advanced Special Steel,Shanghai Key Laboratory of Advanced Ferrometallurgy,Shanghai University(No.SKLASS 2023-03)the Science and Technology Commission of Shanghai Municipality(No.20511107700).
文摘A novel plasma torch nitriding technology was applied for the first time to improve the surface properties of M2 high-speed steel by adjusting different experimental parameters.The nitrogen content,precipitate,microstructure,mechanical property,and corrosion resistance of the nitrided layer were comprehensively analyzed using an ONH analyzer,scanning electron microscope(SEM),micro-area X-ray diffractometer,transmission electron microscope(TEM),Vickers microhardness tester,high-temperature wear tester,3D profilometer,tensile testing machine,and electrochemical workstation.The research results show that the novel plasma torch nitriding technology can achieve synergistic strengthening of nitrogen,carbon,and alloying element solid solution,precipitation strengthening,and martensitic structure on the surface of M2 high-speed steel.The nitrogen content on the specimen surface increased up to 0.17%,while the size and area of carbides were reduced by 89%and 86%,respectively,indicating a transformation towards fine nitrogen-rich precipitates.Compared to the original M2 steel,the nitrided specimens exhibited significant improvements in overall performance.The hardness increased from 228 HV_(0.2)to a maximum of 795 HV_(0.2),the wear coefficient decreased from a maximum of 0.8 to 0.49,the tensile strength increased from 753 MPa to a maximum of 934 MPa,and the corrosion current density decreased from 1.2×10^(−5)to a minimum of 1.9×10^(−6)A/cm^(2).
基金supported by the National Key Research and Development Program of China(2016YFB0301800)the National High Technology Research and Development Program of China(2015AA020201).
文摘The production of medical waste(MW)is a growing concern,particularly in light of the increasing annual generation and the exacerbating effects of the COVID-19 pandemic.Traditional techniques such as incineration and landfilling present significant limitations.In this study,a self-designed 50 kW arc plasma reactor was employed to conduct gasification experiments on nitrile-butadiene rubber(NBR)which served as a model of MWand a mixture of NBR/SiO_(2) which served as a model of glass-containing MW,using CO_(2)as the working gas.The CO_(2)thermal plasma gasification process not only ensures the safe and efficient disposal of MW,but also facilitates its effective conversion into H_(2)and CO,achieving a carbon conversion efficiency of 94.52%.The yields of H2 and CO reached 98.52%and 81.83%,respectively,and the specific energy consumption was as low as 3.55 kW·h·kg^(-1).Furthermore,the addition of SiO_(2) was found to inhibit the gasification of NBR and cause damage to the reactor.Therefore,it is recommended that glass waste should be removed prior to the treatment of MW.The CO_(2)thermal plasma gasification technology can not only eliminate environmental and health risks posed by MW,but also convert it into syngas for further utilization.This provides a promising approach to the harmless and resource disposal of MW,while also contributing to the comprehensive utilization of greenhouse gases.
