The propagation properties of ion-acoustic solitary and shock waves in the magnetized viscous plasma with nonthermal trapped electrons are investigated.The Cairns-Gurevich distribution as the electron distribution is ...The propagation properties of ion-acoustic solitary and shock waves in the magnetized viscous plasma with nonthermal trapped electrons are investigated.The Cairns-Gurevich distribution as the electron distribution is considered to describe the plasma nonthermality and particle trapping.By adopting the reductive perturbation technique,we derived the nonlinear Schamel-Korteweg-de Vries-Burgers(SKdVB)equation,and then obtained the ion-acoustic shock and solitary wave solutions of the SKdVB equation for different limiting cases.It is found that the impact of nonthermal parameterα,external magnetic fieldΩ,obliqueness lz,wave speed U0,and the ion kinematic viscosityη0can significantly change the characteristics of the shock and solitary waves.These results may be useful for better understanding the propagation of nonlinear structures in space(i.e.Earth's magnetosphere and ionosphere,auroral regions)and laboratory plasma with nonthermal trapped electrons.展开更多
In this work,samples consisting of BiVO4 with exposed(040)facets coupled with Bi2S3(Bi2S3/BiVO4)were prepared through a one-pot hydrothermal method,using ethylenediaminetetraacetic acid as directing agent and L-cystei...In this work,samples consisting of BiVO4 with exposed(040)facets coupled with Bi2S3(Bi2S3/BiVO4)were prepared through a one-pot hydrothermal method,using ethylenediaminetetraacetic acid as directing agent and L-cysteine as sulfur source and soft template.X-ray diffraction,field emission scanning electron microscopy,and high-resolution transmission electron microscopy measurements indicated that the Bi2S3 content had a significant influence on the growth of(040)and(121)facets as well as on the morphology of the Bi2S3/BiVO4 samples.When the Bi2S3 content reached 1 mmol,the Bi2S3/BiVO4 samples exhibited a peony-like morphology.The results of transient photocurrent tests and electrochemical impedance spectroscopy measurements confirmed that a more effective charge separation and a faster interfacial charge transfer occurred in Bi2S3/BiVO4 than BiVO4.The enhanced photocatalytic activity of the Bi2S3/BiVO4 samples could be attributed to the improved absorption capability in the visible light region and the enhanced electron-hole pair separation efficiency due to the formation of the Bi2S3/BiVO4 heterostructure.In addition,the Bi2S3/BiVO4 samples showed relative stability and reusability.The simple method presented in this work could be used to fabricate composite photocatalysts with high activity for different applications,such as photocatalytic degradation of organic pollutants,photocatalytic splitting of water,and photocatalytic reduction of carbon dioxide.展开更多
In this study, the influence of minor titanium(Ti) addition on the microstructure and tensile properties of Mg-8Sn-1Zn based alloys were investigated by means of optical microscopy, X-ray diffraction, scanning electro...In this study, the influence of minor titanium(Ti) addition on the microstructure and tensile properties of Mg-8Sn-1Zn based alloys were investigated by means of optical microscopy, X-ray diffraction, scanning electron microscopy, energy dispersive spectrometry, and tensile tests. The results showed that Ti can decrease the secondary dendrite arm spacing(SDAS). The tensile strength of the Mg-8Sn-1Zn-Ti alloys is initially increased by increasing the Ti content up to 0.09 wt.%, but subsequently decreased for further increase of Ti content. The improved tensile properties are attributed to the decreased SDAS and refi ned Mg_2Sn phases, as well as the increased fraction of tin(Sn) segregated regions. The tensile fracture surface of the studied alloys shows mixed characteristics of cleavage and quasi-cleavage fracture. Adding Ti does not significantly change the fracture mode of the studied alloys.展开更多
Biodegradable Mg-xB i(x = 3, 6 and 9wt.%) alloys were fabricated by ingot casting, and the change of corrosion behavior of the alloys in the Hank's solution was analyzed with respect to the microstructure using op...Biodegradable Mg-xB i(x = 3, 6 and 9wt.%) alloys were fabricated by ingot casting, and the change of corrosion behavior of the alloys in the Hank's solution was analyzed with respect to the microstructure using optical micrograph(OM), X-ray diffraction(XRD), scanning electron microscope(SEM) equipped with an energy dispersive X-ray spectrometer(EDS), electrochemical and immersion tests. The results show that the microstructures of the as-cast Mg-Bi alloys mainly consisted of dendritic α-Mg grains and Mg3Bi2 phase in common, with the secondary dendrite arm spacing(SDAS) decreasing significantly from 41.2 μm to 25.4 μm and the fraction of Mg3Bi2 increasing from 3.1% to 10.7%. Furthermore, the corrosion rate increasing from 1.32 mm·a-1 to 8.07 mm·a-1 as the Bi content was increased from 3wt.% to 9wt.%. The reduced corrosion resistance was mainly ascribed to the increasing fraction of the second phase particles, which bring positive effects on the development of pitting.展开更多
The collision frequencies of electron-neutral-particle in weakly ionized complex plasmas with the non-Maxwellian velocity distributions are studied.The average collision frequencies of electron-neutral-particle in pla...The collision frequencies of electron-neutral-particle in weakly ionized complex plasmas with the non-Maxwellian velocity distributions are studied.The average collision frequencies of electron-neutral-particle in plasmas are accurately derived.We find that these collision frequencies are significantly dependent on the power-law spectral indices of non-Maxwellian distribution functions and so they are generally different from the collision frequencies in plasmas with a Maxwellian velocity distribution,which will affect the transport properties of the charged particles in plasmas.Numerically analyses are made to show the roles of the spectral indices in the average collision frequencies respectively.展开更多
Objectives:We used stir-fried oat flour as experimental material and raw oat flour as a control to explore the influence of stir-frying on the storagequalityofoatflour.Materials and Methods:The HS-SPME-GC-MS method co...Objectives:We used stir-fried oat flour as experimental material and raw oat flour as a control to explore the influence of stir-frying on the storagequalityofoatflour.Materials and Methods:The HS-SPME-GC-MS method combined with electronic nose technology was used to understand the lipid stability and analyze the changes in the flavor of the substances during the entire storage period.Results:It was observed that during the storage period,stir-fried oat flour contained less water than raw oat flavor.The former was characterized by a lower fatty acid value,lower acid value,and lower linoleic acid content,but higher oleic acid content and palmitic acid content compared to the latter.With the passage of storage time,the palmitic acid content significantly increased,and the linoleic acid content significantly decreased in raw and stir-fried oats flour(P<o.05).The sulfur and methyl contents in the stir-fried oat flour were higher than those in the raw flour,while nitrogen oxide content in the former was lower than that in the latter.Stir-fried oat flour possessed a total of 78 identified flavor substances.The process of stir-frying boosts the oxidation decomposition of unsaturated fatty acids aldehydes and heterocyclic compounds produced by the Maillard reaction,so the flavor substances of stir-fried oat flour are richer.Conclusions:Stir-fried oat flour,containing diverse types of flavor substances,experienced more obvious flavor changes throughout the storage period than raw oat flour.展开更多
文摘The propagation properties of ion-acoustic solitary and shock waves in the magnetized viscous plasma with nonthermal trapped electrons are investigated.The Cairns-Gurevich distribution as the electron distribution is considered to describe the plasma nonthermality and particle trapping.By adopting the reductive perturbation technique,we derived the nonlinear Schamel-Korteweg-de Vries-Burgers(SKdVB)equation,and then obtained the ion-acoustic shock and solitary wave solutions of the SKdVB equation for different limiting cases.It is found that the impact of nonthermal parameterα,external magnetic fieldΩ,obliqueness lz,wave speed U0,and the ion kinematic viscosityη0can significantly change the characteristics of the shock and solitary waves.These results may be useful for better understanding the propagation of nonlinear structures in space(i.e.Earth's magnetosphere and ionosphere,auroral regions)and laboratory plasma with nonthermal trapped electrons.
文摘In this work,samples consisting of BiVO4 with exposed(040)facets coupled with Bi2S3(Bi2S3/BiVO4)were prepared through a one-pot hydrothermal method,using ethylenediaminetetraacetic acid as directing agent and L-cysteine as sulfur source and soft template.X-ray diffraction,field emission scanning electron microscopy,and high-resolution transmission electron microscopy measurements indicated that the Bi2S3 content had a significant influence on the growth of(040)and(121)facets as well as on the morphology of the Bi2S3/BiVO4 samples.When the Bi2S3 content reached 1 mmol,the Bi2S3/BiVO4 samples exhibited a peony-like morphology.The results of transient photocurrent tests and electrochemical impedance spectroscopy measurements confirmed that a more effective charge separation and a faster interfacial charge transfer occurred in Bi2S3/BiVO4 than BiVO4.The enhanced photocatalytic activity of the Bi2S3/BiVO4 samples could be attributed to the improved absorption capability in the visible light region and the enhanced electron-hole pair separation efficiency due to the formation of the Bi2S3/BiVO4 heterostructure.In addition,the Bi2S3/BiVO4 samples showed relative stability and reusability.The simple method presented in this work could be used to fabricate composite photocatalysts with high activity for different applications,such as photocatalytic degradation of organic pollutants,photocatalytic splitting of water,and photocatalytic reduction of carbon dioxide.
基金supported by the National Natural Science Foundation of China(Grant no.51404166)Shanxi Province Science Foundation for Youths(2013021013-4)+2 种基金Research Project Supported by Shanxi Scholarship Council of China(2014-023)Technological Innovation Programs of Higher Education Institutions Shanxi(Grant no.2014120)the Advanced Programs of Department of Human Resources and Social Security of Shanxi Province for Returned Scholars(2013101)
文摘In this study, the influence of minor titanium(Ti) addition on the microstructure and tensile properties of Mg-8Sn-1Zn based alloys were investigated by means of optical microscopy, X-ray diffraction, scanning electron microscopy, energy dispersive spectrometry, and tensile tests. The results showed that Ti can decrease the secondary dendrite arm spacing(SDAS). The tensile strength of the Mg-8Sn-1Zn-Ti alloys is initially increased by increasing the Ti content up to 0.09 wt.%, but subsequently decreased for further increase of Ti content. The improved tensile properties are attributed to the decreased SDAS and refi ned Mg_2Sn phases, as well as the increased fraction of tin(Sn) segregated regions. The tensile fracture surface of the studied alloys shows mixed characteristics of cleavage and quasi-cleavage fracture. Adding Ti does not significantly change the fracture mode of the studied alloys.
基金supported by the National Natural Science Foundation of China(Grant no.51404166)Shanxi Province Science Foundation for Youths(2013021013-4)+2 种基金the Research Project Supported by Shanxi Scholarship Council of China(2014-023)the Technological Innovation Programs of Higher Education Institutions in Shanxi(Grant no.2014120)the Advanced Programs of Department of Human Resources and Social Security of Shanxi Province for Returned Scholars(2013101)
文摘Biodegradable Mg-xB i(x = 3, 6 and 9wt.%) alloys were fabricated by ingot casting, and the change of corrosion behavior of the alloys in the Hank's solution was analyzed with respect to the microstructure using optical micrograph(OM), X-ray diffraction(XRD), scanning electron microscope(SEM) equipped with an energy dispersive X-ray spectrometer(EDS), electrochemical and immersion tests. The results show that the microstructures of the as-cast Mg-Bi alloys mainly consisted of dendritic α-Mg grains and Mg3Bi2 phase in common, with the secondary dendrite arm spacing(SDAS) decreasing significantly from 41.2 μm to 25.4 μm and the fraction of Mg3Bi2 increasing from 3.1% to 10.7%. Furthermore, the corrosion rate increasing from 1.32 mm·a-1 to 8.07 mm·a-1 as the Bi content was increased from 3wt.% to 9wt.%. The reduced corrosion resistance was mainly ascribed to the increasing fraction of the second phase particles, which bring positive effects on the development of pitting.
基金supported by the National Natural science foundation of China under Grant No.11775156.
文摘The collision frequencies of electron-neutral-particle in weakly ionized complex plasmas with the non-Maxwellian velocity distributions are studied.The average collision frequencies of electron-neutral-particle in plasmas are accurately derived.We find that these collision frequencies are significantly dependent on the power-law spectral indices of non-Maxwellian distribution functions and so they are generally different from the collision frequencies in plasmas with a Maxwellian velocity distribution,which will affect the transport properties of the charged particles in plasmas.Numerically analyses are made to show the roles of the spectral indices in the average collision frequencies respectively.
基金the Major Science and Technology Project of Inner Mongolia Autonomous Region(2021ZD0002),China.
文摘Objectives:We used stir-fried oat flour as experimental material and raw oat flour as a control to explore the influence of stir-frying on the storagequalityofoatflour.Materials and Methods:The HS-SPME-GC-MS method combined with electronic nose technology was used to understand the lipid stability and analyze the changes in the flavor of the substances during the entire storage period.Results:It was observed that during the storage period,stir-fried oat flour contained less water than raw oat flavor.The former was characterized by a lower fatty acid value,lower acid value,and lower linoleic acid content,but higher oleic acid content and palmitic acid content compared to the latter.With the passage of storage time,the palmitic acid content significantly increased,and the linoleic acid content significantly decreased in raw and stir-fried oats flour(P<o.05).The sulfur and methyl contents in the stir-fried oat flour were higher than those in the raw flour,while nitrogen oxide content in the former was lower than that in the latter.Stir-fried oat flour possessed a total of 78 identified flavor substances.The process of stir-frying boosts the oxidation decomposition of unsaturated fatty acids aldehydes and heterocyclic compounds produced by the Maillard reaction,so the flavor substances of stir-fried oat flour are richer.Conclusions:Stir-fried oat flour,containing diverse types of flavor substances,experienced more obvious flavor changes throughout the storage period than raw oat flour.
