Atmospheric pressure cold plasma jets(APCPJs) typically exhibit a slender, conical structure,which imposes limitations on their application for surface modification due to the restricted treatment area. In this paper,...Atmospheric pressure cold plasma jets(APCPJs) typically exhibit a slender, conical structure,which imposes limitations on their application for surface modification due to the restricted treatment area. In this paper, we introduce a novel plasma jet morphology known as the large-scale cold plasma jet(LSCPJ), characterized by the presence of both a central conical plasma jet and a peripheral trumpet-like diffuse plasma jet. The experimental investigations have identified the factors influencing the conical and the trumpet-like diffuse plasma jet, and theoretical simulations have shed light on the role of the flow field and the electric field in shaping the formation of the LSCPJ. It is proved that, under conditions of elevated helium concentration, the distributions of impurity gas particles and the electric field jointly determine the plasma jet’s morphology. High-speed ICCD camera images confirm the dynamic behavior of plasma bullets in LSCPJ, which is consistent with the theoretical analysis. Finally, it is demonstrated that when applied to the surface treatment of silicone rubber, LSCPJ can achieve a treatment area over 28 times larger than that of APCPJ under equivalent conditions. This paper uncovers the crucial role of impurity gases and electric fields in shaping plasma jet morphology and opens up the possibility of efficiently diversifying plasma jet generation effects through external electromagnetic fields. These insights hold the promise of reducing the generation cost of plasma jets and expanding their applications across various industrial sectors.展开更多
In this work,we proposed a diffuse-interface model for the dendritic growth with thermosolutal convection.In this model,the sharp boundary between the fluid and solid dendrite is firstly replaced by a thin but nonzero...In this work,we proposed a diffuse-interface model for the dendritic growth with thermosolutal convection.In this model,the sharp boundary between the fluid and solid dendrite is firstly replaced by a thin but nonzero thickness diffuse interface,which is described by the order parameter,and the diffuse-interface based governing equations for the dendritic growth are presented.To solve the model for the dendritic growth with thermosolutal convection,we also developed a diffuse-interface multirelaxation-time lattice Boltzmann(LB)method.In this method,the order parameter in the phase-field equation is combined into the force caused by the fluid-solid interaction,and the treatment on the complex fluid-solid interface can be avoided.In addition,four LB models are designed for the phase-field equation,concentration equation,temperature equation and the Navier-Stokes equations in a unified framework.Finally,we performed some simulations of the dendritic growth to test the present diffuse-interface LB method,and found that the numerical results are in good agreements with some previous works.展开更多
Plasma water treatment technology, which aims to produce strong oxidizing reactive particles that act on the gas-liquid interface by way of discharging, is used to treat the organic pollutants that do not degrade easi...Plasma water treatment technology, which aims to produce strong oxidizing reactive particles that act on the gas-liquid interface by way of discharging, is used to treat the organic pollutants that do not degrade easily in water. This paper presents a diffuse-discharge plasma water treatment method, which is realized by constructing a conical air gap through an uneven medium layer. The proposed method uses water as one electrode, and a dielectric barrier discharge electrode is constructed by using an uneven dielectric. The electric field distribution in the discharge space will be uneven, wherein the long gap electric field will have a smaller intensity, while the short one will have a larger intensity. A diffuse glow discharge is formed in the cavity. With this type of plasma water treatment equipment, a methyl orange solution with a concentration of 10 mg 1-1 was treated, and the removal rate was found to reach 88.96%.展开更多
We consider the finite element based computation of topological quantities of implicitly represented surfaces within a diffuse interface framework.Utilizing an adaptive finite element implementation with effective gra...We consider the finite element based computation of topological quantities of implicitly represented surfaces within a diffuse interface framework.Utilizing an adaptive finite element implementation with effective gradient recovery techniques,we discuss how the Euler number can be accurately computed directly from the numerically solved phase field functions or order parameters.Numerical examples and applications to the topological analysis of point clouds are also presented.展开更多
Twelve volunteers with normal hearing (9 males and 3 females) participated in this work The sound transfer functions (STFS) from diffuse sound field to the subject's eardrums were measured and correlated...Twelve volunteers with normal hearing (9 males and 3 females) participated in this work The sound transfer functions (STFS) from diffuse sound field to the subject's eardrums were measured and correlated to the temporary threshold shift (TTS) due to fiffuse-exposure.A probe tube with a miniature microphone was used for STF measurements in which successive 1/3 oct bandwidth random noise with central frequency from 0.25 kKz to 8 kHz were used. The subjects were divided into two groups, with the STF maxima at 2 kHz and 4 kHz respectively Pre- and post- exposure sweep Bekesy audiograms were recorded and the temporary thresh old shift calctilated as the difference between the two. Frequency of the maximum TTS was correlated to that of the maximum STF. The average TTS was very small or zero at frequen cies below the band noise exposure , but was noticeable even at the highest measured frequency (8 kHz) for beyond the noise band. Also individual differences in STF were found at frequencies between 2 kHz and 4 kHz展开更多
基金supported by the Guangdong Basic and Applied Basic Research Foundation(No.2023A1515011505)Shenzhen Science and Technology Program(Nos.JCYJ 20220530142808020 and JSGG20220606140202005)+1 种基金China Postdoctoral Science Foundation(No.2023 M731878)Project(No.SKLD22KM17)by State Key Laboratory of Power System Operation and Control。
文摘Atmospheric pressure cold plasma jets(APCPJs) typically exhibit a slender, conical structure,which imposes limitations on their application for surface modification due to the restricted treatment area. In this paper, we introduce a novel plasma jet morphology known as the large-scale cold plasma jet(LSCPJ), characterized by the presence of both a central conical plasma jet and a peripheral trumpet-like diffuse plasma jet. The experimental investigations have identified the factors influencing the conical and the trumpet-like diffuse plasma jet, and theoretical simulations have shed light on the role of the flow field and the electric field in shaping the formation of the LSCPJ. It is proved that, under conditions of elevated helium concentration, the distributions of impurity gas particles and the electric field jointly determine the plasma jet’s morphology. High-speed ICCD camera images confirm the dynamic behavior of plasma bullets in LSCPJ, which is consistent with the theoretical analysis. Finally, it is demonstrated that when applied to the surface treatment of silicone rubber, LSCPJ can achieve a treatment area over 28 times larger than that of APCPJ under equivalent conditions. This paper uncovers the crucial role of impurity gases and electric fields in shaping plasma jet morphology and opens up the possibility of efficiently diversifying plasma jet generation effects through external electromagnetic fields. These insights hold the promise of reducing the generation cost of plasma jets and expanding their applications across various industrial sectors.
基金supported by the National Natural Science Foundation of China under Grants No.12072127,No 51836003,No.52075201 and No.52188102.
文摘In this work,we proposed a diffuse-interface model for the dendritic growth with thermosolutal convection.In this model,the sharp boundary between the fluid and solid dendrite is firstly replaced by a thin but nonzero thickness diffuse interface,which is described by the order parameter,and the diffuse-interface based governing equations for the dendritic growth are presented.To solve the model for the dendritic growth with thermosolutal convection,we also developed a diffuse-interface multirelaxation-time lattice Boltzmann(LB)method.In this method,the order parameter in the phase-field equation is combined into the force caused by the fluid-solid interaction,and the treatment on the complex fluid-solid interface can be avoided.In addition,four LB models are designed for the phase-field equation,concentration equation,temperature equation and the Navier-Stokes equations in a unified framework.Finally,we performed some simulations of the dendritic growth to test the present diffuse-interface LB method,and found that the numerical results are in good agreements with some previous works.
基金supported by National Natural Science Foundation of China (51577011)
文摘Plasma water treatment technology, which aims to produce strong oxidizing reactive particles that act on the gas-liquid interface by way of discharging, is used to treat the organic pollutants that do not degrade easily in water. This paper presents a diffuse-discharge plasma water treatment method, which is realized by constructing a conical air gap through an uneven medium layer. The proposed method uses water as one electrode, and a dielectric barrier discharge electrode is constructed by using an uneven dielectric. The electric field distribution in the discharge space will be uneven, wherein the long gap electric field will have a smaller intensity, while the short one will have a larger intensity. A diffuse glow discharge is formed in the cavity. With this type of plasma water treatment equipment, a methyl orange solution with a concentration of 10 mg 1-1 was treated, and the removal rate was found to reach 88.96%.
基金supported in part by US NSF-DMS 1016073,NSFC 11271350 and 91130019Special Research Funds for State Key Laboratories Y22612A33S+1 种基金China 863 project 2010AA012301 and 2012AA01A304China 973 project 2011CB309702.
文摘We consider the finite element based computation of topological quantities of implicitly represented surfaces within a diffuse interface framework.Utilizing an adaptive finite element implementation with effective gradient recovery techniques,we discuss how the Euler number can be accurately computed directly from the numerically solved phase field functions or order parameters.Numerical examples and applications to the topological analysis of point clouds are also presented.
文摘Twelve volunteers with normal hearing (9 males and 3 females) participated in this work The sound transfer functions (STFS) from diffuse sound field to the subject's eardrums were measured and correlated to the temporary threshold shift (TTS) due to fiffuse-exposure.A probe tube with a miniature microphone was used for STF measurements in which successive 1/3 oct bandwidth random noise with central frequency from 0.25 kKz to 8 kHz were used. The subjects were divided into two groups, with the STF maxima at 2 kHz and 4 kHz respectively Pre- and post- exposure sweep Bekesy audiograms were recorded and the temporary thresh old shift calctilated as the difference between the two. Frequency of the maximum TTS was correlated to that of the maximum STF. The average TTS was very small or zero at frequen cies below the band noise exposure , but was noticeable even at the highest measured frequency (8 kHz) for beyond the noise band. Also individual differences in STF were found at frequencies between 2 kHz and 4 kHz
