Pub Date : 2024-08-08DOI: 10.1088/1361-6463/ad6a24
Longxin Wan, Xiaofei Xu, Kun Duan and Junming Zhao
A broadband optically transparent metasurface microwave absorber (MMA) is designed and experimentally studied. The MMA is made of two indium tin oxide (ITO) resistive films deposited on two transparent polyethylene terephthalate substrates respectively, between which is sandwiched a single air spacer. The top ITO resistive film is etched with periodic interdigital metasurface patterns in rotational symmetry, while the bottom ITO resistive film is an integrated sheet with a low resistance working as the backplane. By carefully optimizing the functional interdigital metasurface structures in a numerical solver, a desirable 4-octave broadband MMA is achieved. The absorbing bandwidth is 4.53–18.71 GHz (122.03%) in the numerical predictions for the perpendicular incidence, in which the absorptivity is greater than 90%. Its total thickness is only 5.8 mm or 0.088λL, where λL is the wavelength (66.23 mm) at the lowest 4.53 GHz. The absorber is validated in experiments. Results are observed in good agreement with the simulated ones. The interdigital MMA is polarization-insensitive and able to operate for wide-angle incidences up to 45°. These properties are demonstrated in both simulations and experiments.
{"title":"Broadband optically transparent microwave absorber made of interdigital metasurfaces in rotational symmetry with a single air spacer","authors":"Longxin Wan, Xiaofei Xu, Kun Duan and Junming Zhao","doi":"10.1088/1361-6463/ad6a24","DOIUrl":"https://doi.org/10.1088/1361-6463/ad6a24","url":null,"abstract":"A broadband optically transparent metasurface microwave absorber (MMA) is designed and experimentally studied. The MMA is made of two indium tin oxide (ITO) resistive films deposited on two transparent polyethylene terephthalate substrates respectively, between which is sandwiched a single air spacer. The top ITO resistive film is etched with periodic interdigital metasurface patterns in rotational symmetry, while the bottom ITO resistive film is an integrated sheet with a low resistance working as the backplane. By carefully optimizing the functional interdigital metasurface structures in a numerical solver, a desirable 4-octave broadband MMA is achieved. The absorbing bandwidth is 4.53–18.71 GHz (122.03%) in the numerical predictions for the perpendicular incidence, in which the absorptivity is greater than 90%. Its total thickness is only 5.8 mm or 0.088λL, where λL is the wavelength (66.23 mm) at the lowest 4.53 GHz. The absorber is validated in experiments. Results are observed in good agreement with the simulated ones. The interdigital MMA is polarization-insensitive and able to operate for wide-angle incidences up to 45°. These properties are demonstrated in both simulations and experiments.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"56 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-08DOI: 10.1088/1361-6463/ad6a21
Xiao Zhang, Tian Xia, Yahui Zhang, Yikun Yang and Bintang Yang
This paper presents a novel non-contact spatial gap distance sensing (GDS) method that can provide distance information in spatial separation conditions. In many applications, such as enclosed environments, it could not provide the desired measurement of gap distance of internal non-magnetic medium due to the constraints of physical barriers and poor accessibility. Therefore, a non-invasive sensing system is designed to measure spatial gap distance for non-magnetic medium. The developed sensor system consists of a pair of heteropolar permanent magnets (PMs), a non-magnetic medium, a magnetostrictive-piezoelectric composite unit and an external space, which has the function of spatial separation measurement. By exploiting the magnetoelectric effect, the magneto-machine-electric conversion is achieved by sensing the spatial magnetic field generated by the heteropolar PMs. The coupling modeling, analysis and calibration of sensing system are conducted, and the system prototype is designed and manufactured. Additionally, the performances of the GDS are experimentally validated. Static gap distance (plate thickness) measurements of the plate and variable gap distance (instant water height) measurements of water are performed, and resolution, vibration, and drift tests are carried out. The results show the accuracy and stability of non-contact spatial gap distance detection for non-magnetic medium, highlighting its potential in various applications.
{"title":"Gap distance sensing for non-magnetic medium based on magnetoelectric effect under spatial separation condition","authors":"Xiao Zhang, Tian Xia, Yahui Zhang, Yikun Yang and Bintang Yang","doi":"10.1088/1361-6463/ad6a21","DOIUrl":"https://doi.org/10.1088/1361-6463/ad6a21","url":null,"abstract":"This paper presents a novel non-contact spatial gap distance sensing (GDS) method that can provide distance information in spatial separation conditions. In many applications, such as enclosed environments, it could not provide the desired measurement of gap distance of internal non-magnetic medium due to the constraints of physical barriers and poor accessibility. Therefore, a non-invasive sensing system is designed to measure spatial gap distance for non-magnetic medium. The developed sensor system consists of a pair of heteropolar permanent magnets (PMs), a non-magnetic medium, a magnetostrictive-piezoelectric composite unit and an external space, which has the function of spatial separation measurement. By exploiting the magnetoelectric effect, the magneto-machine-electric conversion is achieved by sensing the spatial magnetic field generated by the heteropolar PMs. The coupling modeling, analysis and calibration of sensing system are conducted, and the system prototype is designed and manufactured. Additionally, the performances of the GDS are experimentally validated. Static gap distance (plate thickness) measurements of the plate and variable gap distance (instant water height) measurements of water are performed, and resolution, vibration, and drift tests are carried out. The results show the accuracy and stability of non-contact spatial gap distance detection for non-magnetic medium, highlighting its potential in various applications.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"18 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-08DOI: 10.1088/1361-6463/ad6878
Kyunho Kim, Cheolwoo Bong and Moon Soo Bak
Laser absorption measurements were conducted on a high-density, laser-induced plasma produced in atmospheric-pressure air to investigate the spatiotemporal evolution of its electron number density. Measurements taken both along and perpendicular to the plasma’s symmetric axis showed that, upon formation, the plasma propagates in the direction opposite to the laser beam used for plasma generation, while expanding rapidly radially. The spatiotemporal evolution of the electron density was further analyzed from the measurements taken perpendicular to the plasma’s symmetric axis through tomographic reconstruction. Notably, the reconstruction was achieved using a genetic algorithm, as a probe laser beam used for absorption measurement is non-negligible in size compared to the plasma. Importantly, our measurements could reveal that the electron density reaches 4.99 × 1019 cm−3 immediately after the plasma formation at the center; moreover, there is a development of a pressure wave with high electron density, propagating outward radially due to the rapid expansion of the produced plasma.
{"title":"Spatiotemporal measurement of electron number density in high density laser-induced plasmas using laser absorption","authors":"Kyunho Kim, Cheolwoo Bong and Moon Soo Bak","doi":"10.1088/1361-6463/ad6878","DOIUrl":"https://doi.org/10.1088/1361-6463/ad6878","url":null,"abstract":"Laser absorption measurements were conducted on a high-density, laser-induced plasma produced in atmospheric-pressure air to investigate the spatiotemporal evolution of its electron number density. Measurements taken both along and perpendicular to the plasma’s symmetric axis showed that, upon formation, the plasma propagates in the direction opposite to the laser beam used for plasma generation, while expanding rapidly radially. The spatiotemporal evolution of the electron density was further analyzed from the measurements taken perpendicular to the plasma’s symmetric axis through tomographic reconstruction. Notably, the reconstruction was achieved using a genetic algorithm, as a probe laser beam used for absorption measurement is non-negligible in size compared to the plasma. Importantly, our measurements could reveal that the electron density reaches 4.99 × 1019 cm−3 immediately after the plasma formation at the center; moreover, there is a development of a pressure wave with high electron density, propagating outward radially due to the rapid expansion of the produced plasma.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"6 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-08DOI: 10.1088/1361-6463/ad6999
Anand Pandey, Tarun Kumar, Arnab Mondal and Ankush Bag
Carrier selective contacts are a primary requirement for fabricating silicon heterojunction solar cells (SHSCs). TiO2 is a prominent carrier selective contact in SHSCs owing to its excellent optoelectronic features such as suitable band offset, work function, and cost-effectiveness. Herein, we fabricated simple SHSCs in an Al/TiO2/p-Si/Ti/Au device configuration. Ultrathin 3 nm TiO2 layers were deposited onto a p-type silicon substrate using the atomic layer deposition method. The deposition temperature of TiO2 layers varied from 100 °C to 250 °C. X-ray photoelectron spectroscopic studies suggest that deposition temperature highly affects the chemical states of TiO2 and reduces the formation of defective state densities at the Fermi energy. The optical band gap values of TiO2 layers are also altered from 3.13 eV to 3.27 eV when the deposition temperature increases. The work function tuning from −5.13 eV to −4.83 eV has also been observed in TiO2 layers, suggesting the variation in Fermi level tuning, which arises due to changes in carrier concentrations at higher temperatures. Several device parameters, such as ideality factor, trap density, reverse saturation current density, barrier height, etc, have been quantified to comprehend the effects of deposition temperature on photovoltaic device performance. The results suggest that the deposition temperature significantly influences the charge transport and device performance. At an optimum temperature, a significant reduction in charge carrier recombination and trap state density has been observed, which helps to improve power conversion efficiency.
载流子选择性触点是制造硅异质结太阳能电池（SHSCs）的首要条件。二氧化钛具有良好的光电特性，如合适的带偏移、功函数和成本效益，因此在异质结太阳能电池中是一种重要的载流子选择性触点。在此，我们采用 Al/TiO2/p-Si/Ti/Au 器件配置制造了简单的 SHSC。利用原子层沉积法在 p 型硅衬底上沉积了 3 nm 的超薄 TiO2 层。TiO2 层的沉积温度从 100 °C 到 250 °C 不等。X 射线光电子能谱研究表明，沉积温度对二氧化钛的化学态有很大影响，并降低了费米能处缺陷态密度的形成。当沉积温度升高时，TiO2 层的光带隙值也从 3.13 eV 变为 3.27 eV。在二氧化钛层中还观察到工作函数从-5.13 eV调谐到-4.83 eV，这表明费米级调谐的变化是由于在较高温度下载流子浓度的变化引起的。为了理解沉积温度对光伏器件性能的影响，我们对ideality factor、阱密度、反向饱和电流密度、势垒高度等器件参数进行了量化。结果表明，沉积温度对电荷传输和器件性能有重大影响。在最佳温度下，电荷载流子重组和阱态密度显著降低，有助于提高功率转换效率。
{"title":"Optimizing charge transport and band-offset in silicon heterojunction solar cells: impact of TiO2 contact deposition temperature","authors":"Anand Pandey, Tarun Kumar, Arnab Mondal and Ankush Bag","doi":"10.1088/1361-6463/ad6999","DOIUrl":"https://doi.org/10.1088/1361-6463/ad6999","url":null,"abstract":"Carrier selective contacts are a primary requirement for fabricating silicon heterojunction solar cells (SHSCs). TiO2 is a prominent carrier selective contact in SHSCs owing to its excellent optoelectronic features such as suitable band offset, work function, and cost-effectiveness. Herein, we fabricated simple SHSCs in an Al/TiO2/p-Si/Ti/Au device configuration. Ultrathin 3 nm TiO2 layers were deposited onto a p-type silicon substrate using the atomic layer deposition method. The deposition temperature of TiO2 layers varied from 100 °C to 250 °C. X-ray photoelectron spectroscopic studies suggest that deposition temperature highly affects the chemical states of TiO2 and reduces the formation of defective state densities at the Fermi energy. The optical band gap values of TiO2 layers are also altered from 3.13 eV to 3.27 eV when the deposition temperature increases. The work function tuning from −5.13 eV to −4.83 eV has also been observed in TiO2 layers, suggesting the variation in Fermi level tuning, which arises due to changes in carrier concentrations at higher temperatures. Several device parameters, such as ideality factor, trap density, reverse saturation current density, barrier height, etc, have been quantified to comprehend the effects of deposition temperature on photovoltaic device performance. The results suggest that the deposition temperature significantly influences the charge transport and device performance. At an optimum temperature, a significant reduction in charge carrier recombination and trap state density has been observed, which helps to improve power conversion efficiency.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"23 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-08DOI: 10.1088/1361-6463/ad6a22
Chaimae Babori, Mahmoud Barati, Valentin Segouin, Romain Corcolle and Laurent Daniel
This study investigates anhysteretic strains in PZT ceramics. The anhysteretic curves are associated with a stable balanced state of polarization in the domain structure, excluding dissipative effects related to mechanisms such as domain wall pinning. Anhysteretic measurements are representative of an -ideal- scenario in which the material would undergo no energy loss due to dissipative processes, focusing on the stable and reversible aspects of the domain configuration. The different methodologies employed to measure deformations under electromechanical loading are presented, leading to the introduction of digital image correlation (DIC) as the chosen technique, recognized for its ability to capture detailed information on transverse and longitudinal strain. The article then describes a procedure developed to obtain anhysteretic strain and anhysteretic polarisation for different levels of compressive loadings. The subsequent presentation of the results of the transverse and longitudinal strain analyses provides valuable insights into the reversible and irreversible behavior of the material. They can be used as a basis for the thermodynamical modelling approaches grounded on separating reversible and irreversible contributions or as a validation of existing models describing anhysteretic behavior. The compressive stress affects both the shape of hysteretic and anhysteretic curves. The anhysteretic curve represents a stable equilibrium in the domain structure. Compressive stress reduces strain by affecting the pinning of domain walls. These points justify the interest in studying the effect of compressive stress on the anhysteretic behavior of ferroelectrics.
{"title":"Anhysteretic strains in ferroelectric ceramics under electromechanical loading","authors":"Chaimae Babori, Mahmoud Barati, Valentin Segouin, Romain Corcolle and Laurent Daniel","doi":"10.1088/1361-6463/ad6a22","DOIUrl":"https://doi.org/10.1088/1361-6463/ad6a22","url":null,"abstract":"This study investigates anhysteretic strains in PZT ceramics. The anhysteretic curves are associated with a stable balanced state of polarization in the domain structure, excluding dissipative effects related to mechanisms such as domain wall pinning. Anhysteretic measurements are representative of an -ideal- scenario in which the material would undergo no energy loss due to dissipative processes, focusing on the stable and reversible aspects of the domain configuration. The different methodologies employed to measure deformations under electromechanical loading are presented, leading to the introduction of digital image correlation (DIC) as the chosen technique, recognized for its ability to capture detailed information on transverse and longitudinal strain. The article then describes a procedure developed to obtain anhysteretic strain and anhysteretic polarisation for different levels of compressive loadings. The subsequent presentation of the results of the transverse and longitudinal strain analyses provides valuable insights into the reversible and irreversible behavior of the material. They can be used as a basis for the thermodynamical modelling approaches grounded on separating reversible and irreversible contributions or as a validation of existing models describing anhysteretic behavior. The compressive stress affects both the shape of hysteretic and anhysteretic curves. The anhysteretic curve represents a stable equilibrium in the domain structure. Compressive stress reduces strain by affecting the pinning of domain walls. These points justify the interest in studying the effect of compressive stress on the anhysteretic behavior of ferroelectrics.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"34 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-07DOI: 10.1088/1361-6463/ad5b6c
Manuel Fregolent, Francesco Piva, Matteo Buffolo, Carlo De Santi, Andrea Cester, Masataka Higashiwaki, Gaudenzio Meneghesso, Enrico Zanoni and Matteo Meneghini
The study of deep-level defects in semiconductors has always played a strategic role in the development of electronic and optoelectronic devices. Deep levels have a strong impact on many of the device properties, including efficiency, stability, and reliability, because they can drive several physical processes. Despite the advancements in crystal growth, wide- and ultrawide-bandgap semiconductors (such as gallium nitride and gallium oxide) are still strongly affected by the formation of defects that, in general, can act as carrier traps or generation-recombination centers (G-R). Conventional techniques used for deep-level analysis in silicon need to be adapted for identifying and characterizing defects in wide-bandgap materials. This topical review paper presents an overview of reviews of the theory of deep levels in semiconductors; in addition, we present a review and original results on the application, limits, and perspectives of two widely adopted common deep-level detection techniques, namely capacitance deep-level transient spectroscopy and deep-level optical spectroscopy, with specific focus on wide-bandgap semiconductors. Finally, the most common traps of GaN and β-Ga2O3 are reviewed.
对半导体深层缺陷的研究在电子和光电设备的发展中一直发挥着战略性作用。深层缺陷对器件的许多特性（包括效率、稳定性和可靠性）都有很大影响，因为它们可以驱动多个物理过程。尽管晶体生长技术不断进步，但宽带隙和超宽带隙半导体（如氮化镓和氧化镓）仍然受到缺陷形成的强烈影响，这些缺陷一般可作为载流子陷阱或世代重组中心（G-R）。用于硅深层分析的传统技术需要进行调整，以识别和表征宽带隙材料中的缺陷。这篇专题综述论文概述了半导体中深电平理论的综述；此外，我们还介绍了两种广泛采用的常用深电平检测技术（即电容深电平瞬态光谱法和深电平光学光谱法）的应用、限制和前景方面的综述和原创性成果，并特别关注宽带隙半导体。最后，综述了 GaN 和 β-Ga2O3 最常见的陷阱。
{"title":"Advanced defect spectroscopy in wide-bandgap semiconductors: review and recent results","authors":"Manuel Fregolent, Francesco Piva, Matteo Buffolo, Carlo De Santi, Andrea Cester, Masataka Higashiwaki, Gaudenzio Meneghesso, Enrico Zanoni and Matteo Meneghini","doi":"10.1088/1361-6463/ad5b6c","DOIUrl":"https://doi.org/10.1088/1361-6463/ad5b6c","url":null,"abstract":"The study of deep-level defects in semiconductors has always played a strategic role in the development of electronic and optoelectronic devices. Deep levels have a strong impact on many of the device properties, including efficiency, stability, and reliability, because they can drive several physical processes. Despite the advancements in crystal growth, wide- and ultrawide-bandgap semiconductors (such as gallium nitride and gallium oxide) are still strongly affected by the formation of defects that, in general, can act as carrier traps or generation-recombination centers (G-R). Conventional techniques used for deep-level analysis in silicon need to be adapted for identifying and characterizing defects in wide-bandgap materials. This topical review paper presents an overview of reviews of the theory of deep levels in semiconductors; in addition, we present a review and original results on the application, limits, and perspectives of two widely adopted common deep-level detection techniques, namely capacitance deep-level transient spectroscopy and deep-level optical spectroscopy, with specific focus on wide-bandgap semiconductors. Finally, the most common traps of GaN and β-Ga2O3 are reviewed.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"9 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-07DOI: 10.1088/1361-6463/ad6877
Yongfeng Xu, Liang Yang, Jiaqi Li, Dongjian Zhou, Qingwei Li, Wenbo Shi and Yuqi Jin
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.
{"title":"Effect of laser wavelength on ablation propulsion and plasma characteristics with acrylonitrile butadiene styrene target","authors":"Yongfeng Xu, Liang Yang, Jiaqi Li, Dongjian Zhou, Qingwei Li, Wenbo Shi and Yuqi Jin","doi":"10.1088/1361-6463/ad6877","DOIUrl":"https://doi.org/10.1088/1361-6463/ad6877","url":null,"abstract":"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.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"26 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-07DOI: 10.1088/1361-6463/ad699a
Huanmin Yao, Haibao Mu, He Li, Zhiyuan Qian, Chengshan Liu, Wendong Li, Daning Zhang and Guanjun Zhang
Using the AC electric field to induce the orientation of nonlinear conductive fillers in composites is an effective solution for alleviating electric field distortion in power modules. However, the mechanism by which the electric field affects the filler dynamic characteristics and the composites’ electrical properties remains unclear. In this paper, the correlation between the microscopic dynamic processes of fillers and the macroscopic current amplitude was analyzed. The results show that the current increases rapidly (0 ∼ 173 s) and then slowly (173 ∼ 869 s) at 600 V mm−1, influenced by the rotation and attraction processes of the fillers. This demonstrates that the orientation stops at about 869 s and the filler orientation state is a key factor in determining the dielectric properties. Secondly, the global orientation evaluation index D for the filler network was proposed, which can also derive the minimum time and energy loss required for preparation. Finally, the impact of different filler orientations on the composites’ conductivity was investigated. In the low electric field stress region, with the average carrier jump distance decreasing from 150.23 to 109.71 nm as the D increases from −0.93 to −0.05. On this basis, materials with nonlinear conductivity gradient distribution can be easily prepared. Before optimization, the electric field stress of the power module at the triple point was 35.79 kV. This composite can reduce the value to 15.42 kV, a decrease of 56.9%, while maintaining good electric field uniformity.
{"title":"The mechanism of tuning filler orientation degree in composites based on AC electric field assist: from microscopic dynamical model to macroscopic electrical properties","authors":"Huanmin Yao, Haibao Mu, He Li, Zhiyuan Qian, Chengshan Liu, Wendong Li, Daning Zhang and Guanjun Zhang","doi":"10.1088/1361-6463/ad699a","DOIUrl":"https://doi.org/10.1088/1361-6463/ad699a","url":null,"abstract":"Using the AC electric field to induce the orientation of nonlinear conductive fillers in composites is an effective solution for alleviating electric field distortion in power modules. However, the mechanism by which the electric field affects the filler dynamic characteristics and the composites’ electrical properties remains unclear. In this paper, the correlation between the microscopic dynamic processes of fillers and the macroscopic current amplitude was analyzed. The results show that the current increases rapidly (0 ∼ 173 s) and then slowly (173 ∼ 869 s) at 600 V mm−1, influenced by the rotation and attraction processes of the fillers. This demonstrates that the orientation stops at about 869 s and the filler orientation state is a key factor in determining the dielectric properties. Secondly, the global orientation evaluation index D for the filler network was proposed, which can also derive the minimum time and energy loss required for preparation. Finally, the impact of different filler orientations on the composites’ conductivity was investigated. In the low electric field stress region, with the average carrier jump distance decreasing from 150.23 to 109.71 nm as the D increases from −0.93 to −0.05. On this basis, materials with nonlinear conductivity gradient distribution can be easily prepared. Before optimization, the electric field stress of the power module at the triple point was 35.79 kV. This composite can reduce the value to 15.42 kV, a decrease of 56.9%, while maintaining good electric field uniformity.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"10 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-06DOI: 10.1088/1361-6463/ad687e
Pengyu Zhao, Yikang Jia, Sihong Ma, Rui Zhang, Kaiyu Li, Tianyi Song, Jianbao Zheng, Jingyao Zhang, Li Guo, Dingxin Liu, Xiaohua Wang and Mingzhe Rong
Methicillin-resistant Staphylococcus aureus (MRSA) presents a significant threat due to the multiple resistance to antibiotics, leading to severe and challenging-to-treat infections. Plasma-activated saline (PAS) prepared by plasma gases, could efficiently inactivate various pathogenic bacteria including both sensitive and antibiotic-resistant bacteria. In this study, the PAS was prepared by plasma gases with different ratios of N2 and O2 activated by gliding arc discharge. First, the gaseous reactive species in the plasma gases were compared, revealing that the highest levels of NOx including NO2 and N2O5 were generated in the gases with the N2/O2 ratios of 4:6, 5:5, and 6:4. Subsequently, the PAS prepared by the two plasma-activated gases at the N2/O2 ratios of 5:5 and 6:4 exhibited the strongest inactivation effects on both planktic MRSA and biofilms. Furthermore, the aqueous reactive species in the PAS exhibited varied change trends with the increasing N2/O2 ratios. Additionally, ultraviolet spectroscopy combined with the probe of N, N-diethyl-p-phenylenediamine was applied for the detection of O2NOO− in the PAS, and the levels of O2NOO− in the PAS were positively correlated with the inactivation effects. Moreover, the PAS induced varying levels of nitration modification on the soluble proteins in MRSA cells, which were related to the intensities of O2NOO− in the PAS. This study regulated the reactive species in the PAS through gas composition and explored the inactivation mechanism of the PAS, providing a new strategy to promote the preparation efficiency of plasma-activated solutions for biomedical applications.
{"title":"Comparison of plasma-activated saline prepared with plasma gases with different N2/O2 ratios activated by gliding arc discharge","authors":"Pengyu Zhao, Yikang Jia, Sihong Ma, Rui Zhang, Kaiyu Li, Tianyi Song, Jianbao Zheng, Jingyao Zhang, Li Guo, Dingxin Liu, Xiaohua Wang and Mingzhe Rong","doi":"10.1088/1361-6463/ad687e","DOIUrl":"https://doi.org/10.1088/1361-6463/ad687e","url":null,"abstract":"Methicillin-resistant Staphylococcus aureus (MRSA) presents a significant threat due to the multiple resistance to antibiotics, leading to severe and challenging-to-treat infections. Plasma-activated saline (PAS) prepared by plasma gases, could efficiently inactivate various pathogenic bacteria including both sensitive and antibiotic-resistant bacteria. In this study, the PAS was prepared by plasma gases with different ratios of N2 and O2 activated by gliding arc discharge. First, the gaseous reactive species in the plasma gases were compared, revealing that the highest levels of NOx including NO2 and N2O5 were generated in the gases with the N2/O2 ratios of 4:6, 5:5, and 6:4. Subsequently, the PAS prepared by the two plasma-activated gases at the N2/O2 ratios of 5:5 and 6:4 exhibited the strongest inactivation effects on both planktic MRSA and biofilms. Furthermore, the aqueous reactive species in the PAS exhibited varied change trends with the increasing N2/O2 ratios. Additionally, ultraviolet spectroscopy combined with the probe of N, N-diethyl-p-phenylenediamine was applied for the detection of O2NOO− in the PAS, and the levels of O2NOO− in the PAS were positively correlated with the inactivation effects. Moreover, the PAS induced varying levels of nitration modification on the soluble proteins in MRSA cells, which were related to the intensities of O2NOO− in the PAS. This study regulated the reactive species in the PAS through gas composition and explored the inactivation mechanism of the PAS, providing a new strategy to promote the preparation efficiency of plasma-activated solutions for biomedical applications.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"61 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-06DOI: 10.1088/1361-6463/ad687d
A Pascale, T Lafleur and C S Corr
The feed gas injection configuration in radio-frequency (RF) inductively coupled plasma (ICP) torches plays a critical role in discharge stability, gas heating, and device thermal management: particularly if a supersonic nozzle is used to subsequently accelerate the hot gas. A novel injection configuration is the bidirectional vortex, which segments the internal ICP flow field into two counter-propagating vortices that can significantly enhance gas heating and reduce heat losses. The diameter of the interface between the vortices (known as the mantle) is expected to be an important dimensional parameter affecting torch operation, especially relative to the nozzle size. In this work, we investigate the effect of nozzle throat diameter on the behaviour and performance of a vortex-enhanced supersonic ICP torch. The system is operated at RF powers and argon mass flow rates between 200–1000 W and 0–400 mg s−1 respectively, and different nozzle diameters ranging from 1.5 to 4 mm are explored. Because of the high-temperature environment, and to prevent disruption of the vortex flow fields, non-invasive diagnostics are used to measure the gas temperature and plasma density, and to infer the torch thermal efficiency and achievable gas specific enthalpy change. The maximum temperature is between 8500–9500 K with the 1.5 mm nozzle giving the highest temperature for a given power and mass flow rate, while plasma densities vary between 1020–1021 m−3 depending on the operating conditions. The thermal efficiency increases from 29% for the 1.5 mm nozzle to just above 70% for the 4 mm nozzle with a similar maximum specific enthalpy of around 1.5 MJ kg−1. These results demonstrate the important coupling between torch properties, and how system optimization can lead to tailored performance of potential interest to several ground and space-based applications.
{"title":"Parametric study of a vortex-enhanced supersonic inductive plasma torch","authors":"A Pascale, T Lafleur and C S Corr","doi":"10.1088/1361-6463/ad687d","DOIUrl":"https://doi.org/10.1088/1361-6463/ad687d","url":null,"abstract":"The feed gas injection configuration in radio-frequency (RF) inductively coupled plasma (ICP) torches plays a critical role in discharge stability, gas heating, and device thermal management: particularly if a supersonic nozzle is used to subsequently accelerate the hot gas. A novel injection configuration is the bidirectional vortex, which segments the internal ICP flow field into two counter-propagating vortices that can significantly enhance gas heating and reduce heat losses. The diameter of the interface between the vortices (known as the mantle) is expected to be an important dimensional parameter affecting torch operation, especially relative to the nozzle size. In this work, we investigate the effect of nozzle throat diameter on the behaviour and performance of a vortex-enhanced supersonic ICP torch. The system is operated at RF powers and argon mass flow rates between 200–1000 W and 0–400 mg s−1 respectively, and different nozzle diameters ranging from 1.5 to 4 mm are explored. Because of the high-temperature environment, and to prevent disruption of the vortex flow fields, non-invasive diagnostics are used to measure the gas temperature and plasma density, and to infer the torch thermal efficiency and achievable gas specific enthalpy change. The maximum temperature is between 8500–9500 K with the 1.5 mm nozzle giving the highest temperature for a given power and mass flow rate, while plasma densities vary between 1020–1021 m−3 depending on the operating conditions. The thermal efficiency increases from 29% for the 1.5 mm nozzle to just above 70% for the 4 mm nozzle with a similar maximum specific enthalpy of around 1.5 MJ kg−1. These results demonstrate the important coupling between torch properties, and how system optimization can lead to tailored performance of potential interest to several ground and space-based applications.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"20 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：