Journal of Physics D: Applied Physics最新文献

{"title":"Light-induced fading effects on TL and OSL signals and feasibility of dose re-assessment with PTTL signals in BeO dosimeters","authors":"Engin Aşlar","doi":"10.1088/1361-6463/ad6fb2","DOIUrl":"https://doi.org/10.1088/1361-6463/ad6fb2","url":null,"abstract":"This study aims to investigate both light-induced fading effects on thermoluminescence (TL) and optically stimulated luminescence (OSL) signals under three different light sources (fluorescent, UV-254 and daylight) and dose reassessment with phototransferred TL (PTTL) signals in Beryllium oxide dosimeters. TL and OSL signals were deconvoluted for each light source. Accordingly, variations in the maximum peak temperature, activation energy, peak area value for the TL signal, and intensity and lifetime values for the OSL signal were monitored. Each peak, OSL component, and total area value exhibited different behaviors depending on the light source. Considering the total area condition, the TL intensity decreased by ∼90%, ∼80%, and ∼70% in UV-254, daylight, and fluorescent light exposure, respectively, at the end of the 120 min. On the other hand, the OSL total area intensity faded quickly for both UV-254 and daylight, while it decreased by ∼45% for fluorescent light. According to these results, regardless of TL and OSL measurements, the dosimeters should be kept primarily away from daylight and fluorescent light after irradiation, instead of UV-254, which is rarely encountered in daily life. The feasibility of dose reassessment using PTTL signals under UV-254 light was investigated within a wide dose range from 0.1 to 128 Gy. It is feasible to reassess doses between 0.5 and 32 Gy considering the total area intensity of PTTL signals. In conclusion, PTTL signals can be easily used in fields of the order of Gy, such as in reevaluating doses in radiotherapy applications.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"40 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223016","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}

{"title":"Low-current gliding DC discharge in high-speed flows","authors":"K N Kornev, A A Logunov, S A Dvinin","doi":"10.1088/1361-6463/ad726e","DOIUrl":"https://doi.org/10.1088/1361-6463/ad726e","url":null,"abstract":"A low-current gliding discharge (current range 1–5 A) in high-speed air flows of 100–250 m s⁻¹ was experimentally studied. A high-voltage direct current source with a maximum voltage of 4.5 kV was used to create the discharge. The average electron concentration <italic toggle=\"yes\">n</italic>_e ∼ 10¹⁴ cm⁻³ and the plasma ionization degree were determined by measuring the Stark broadening of the hydrogen H<italic toggle=\"yes\">_β</italic> line (<italic toggle=\"yes\">λ</italic>_{H<italic toggle=\"yes\">β</italic>} = 486.1 nm). The estimates of the electric field (<italic toggle=\"yes\">E</italic> ∼ 100 V cm ⁻¹ ÷ 600 V cm⁻¹) in the discharge positive column were found using time-synchronized high-speed video recordings and oscillograms. The gas rotational temperature <italic toggle=\"yes\">T</italic>_g = 7000–9500 K and the vibrational temperature <italic toggle=\"yes\">T</italic>_v = 7000–11 000 K were estimated using optical emission spectroscopy. Time-resolved spectroscopy is used to investigate the effective plasma channel spatial regions from which the N, NH, N₂⁺, O and OH molecules radiate. The difference of the obtained radii indicates the presence of a radial temperature gradient and inhomogeneous plasma composition in the discharge cross section. The possibility of using of gliding discharge to ignite hydrocarbon-air mixtures in the ramjet engines combustors has been experimentally demonstrated.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"5 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223020","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}

{"title":"Silicon-based perovskite plasmonic diode with highly polarized emission","authors":"Xin-Rui Mao, Zihao Chu, Xiaogen Yi, Riyu Cong, Yanping Li, Wanjin Xu, Guangzhao Ran","doi":"10.1088/1361-6463/ad7037","DOIUrl":"https://doi.org/10.1088/1361-6463/ad7037","url":null,"abstract":"Here, we propose and develop a silicon (Si)-based perovskite plasmon-emitting diode (PED) with controlled linear polarization in this study. Such polarization originates from the efficient excitation of surface plasmons by excitons in the active layer of the device and the efficient outcoupling by a wedged boundary of a metal electrode. Furthermore, a p-type Si substrate serves as an anode of the diode, and a hole blocking layer of SiO₂ is introduced in the PEDOT:PSS/Si heterojunction for carrier injection balance. Pure green emission light has been achieved from devices with varied thicknesses of the emitting layer, and the maximum degree of polarization is measured to be 0.79. The field distribution and polarization of the PED were simulated and measured. Such a low-cost Si-based plasmonic diode provides a promising way to realize simpler and more compact multiple-functional light sources, which are extensively demanded for optoelectronic integration.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"60 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223019","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}

{"title":"Importance of gas heating in capacitively coupled radiofrequency plasma-assisted synthesis of carbon nanomaterials","authors":"Tanvi Nikhar, Sankhadeep Basu, Shota Abe, Shurik Yatom, Yevgeny Raitses, Rebecca Anthony, Sergey V Baryshev","doi":"10.1088/1361-6463/ad6d78","DOIUrl":"https://doi.org/10.1088/1361-6463/ad6d78","url":null,"abstract":"In pursuit of diamond nanoparticles, a capacitively-coupled radio frequency flow-through plasma reactor was operated with methane-argon gas mixtures. Signatures of the final product obtained microscopically and spectroscopically indicated that the product was an amorphous form of graphite. This result was consistent irrespective of combinations of the macroscopic reactor settings. To explain the observed synthesis output, measurements of C₂ and gas properties were carried out by laser-induced fluorescence and optical emission spectroscopy. Strikingly, the results indicated a strong gas temperature gradient of 100 K per mm from the center of the reactor to the wall. Based on additional plasma imaging, a model of hot constricted region (filamentation region) was then formulated. It illustrated that, while the hot constricted region was present, the bulk of the gas was not hot enough to facilitate diamond <italic toggle=\"yes\">sp</italic>³ formation: characterized by much lower reaction rates, when compared to <italic toggle=\"yes\">sp</italic>², <italic toggle=\"yes\">sp</italic>³ formation kinetics are expected to become exponentially slow. This result was further confirmed by experiments under identical conditions but with a H₂/CH₄ mixture, where no output material was detected: if graphitic <italic toggle=\"yes\">sp</italic>² formation was expected as the main output material from the methane feedstock, atomic hydrogen would then be expected to etch it away <italic toggle=\"yes\">in situ</italic>, such that the net production of that <italic toggle=\"yes\">sp</italic>²-hybridized solid material is nearly a zero. Finally, the crucial importance of gas heating was corroborated by replacing RF with microwave source whereby facile <italic toggle=\"yes\">sp</italic>³ production was attained with H₂/CH₄ gas mixture.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"7 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223021","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}

{"title":"Discharge fault type identification of C4F7N/CO2/O2 mixed insulating gas for engineering based on product components","authors":"Guangkai Cui, Cong Wang, Yuan Yang, Hao Wang, Youping Tu, Zhong Zheng, Hua Jin","doi":"10.1088/1361-6463/ad714c","DOIUrl":"https://doi.org/10.1088/1361-6463/ad714c","url":null,"abstract":"Perfluoroisobutyronitrile (C₄F₇N) gas mixture is considered one of the most promising alternative gases for SF₆ due to its excellent environmental protection and insulation performance. At present, the Shanghai region of China has adopted 8.5% C₄F₇N-86% CO₂-5.5% O₂ proportion gas mixture as the insulation medium for 126 kV gas insulated switchgear and has put it into practical engineering application. This paper conducted decomposition experiments on the proportion gas mixture under spark discharge, suspension discharge, and corona discharge conditions, respectively. The composition analysis of the decomposition products was carried out using a gas chromatography mass spectrometry and a gas chromatography-pulsed discharge helium ionization detector, which got decomposition products of the C₄F₇N/CO₂/O₂ gas mixture under discharge faults mainly include CO, CF₄, C₃F₈, C₄F₈, C₃F₆, and CF₃CN. According to the decomposition path of the C₄F₇N gas mixture, this paper selected three primary decomposition products (CO, CF₄, C₃F₈) and one secondary decomposition product (C₄F₈) for the correlation characterization of discharge types, and proposed the ratios of c(CO)/c(CF₄) and c(C₄F₈)/c(C₃F₈) as the characteristic quantities to characterize the different discharge types. Finally, in order to accurately identify the C₄F₇N/CO₂/O₂ gas mixture discharge type, this paper chose the decision tree algorithm to build a identification tree. The final identification result indicates that the ratio of c (CO)/c (CF₄) and c (C₄F₈)/c (C₃F₈) can be used as the identification criterion for typical discharge fault types.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"34 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223023","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}

{"title":"Oxidative aggregation of hemoglobin–a mechanism for low-temperature plasma-mediated wound healing","authors":"Irina Oganesyan, Alina Begley, Dušan Mrđenović, Julian A Harrison, Renato Zenobi","doi":"10.1088/1361-6463/ad6e99","DOIUrl":"https://doi.org/10.1088/1361-6463/ad6e99","url":null,"abstract":"Plasma medicine is a field that utilizes reactive species generated from atmospheric low-temperature plasmas for applications such as sterilization, blood coagulation, and cancer therapy. Commercial plasma devices are available for wound healing, but research on the chemical modifications induced by these plasmas is scarce. This study explores the chemical modifications in hemoglobin when exposed to a helium plasma dielectric barrier discharge, with the aim of explaining the potential mechanisms through which it contributes to blood coagulation and enhances wound healing. Optical microscopy of cold atmospheric plasma (CAP) treated whole capillary blood showed an increase in red blood cell (RBC) size and the formation of rouleaux structures. The treatment of whole blood leads to hemolysis of RBCs and the release of intracellular protein content. We then treated purified hemoglobin protein at physiological concentrations, which led to the formation of aggregates that could be observed using ion mobility mass spectrometry (IM–MS), size exclusion chromatography, and optical microscopy. The aggregates formed fibril-like structures as observed using atomic force microscopy. The formation of hemoglobin aggregates is hypothesized to be the result of new intermolecular interactions formed following the CAP-mediated protein oxidation. We studied the changes to hemoglobin structure after treatment with a CAP using high-resolution MS and found that the hemoglobin subunits are oxidized with the addition of at least 4 oxygen atoms each. The intact tetrameric hemoglobin structure remains unchanged; however, the monomeric and dimeric proteins adopt a more compact structure, as observed by IM–MS. We propose that CAP treatment of fresh blood leads to hemolysis, and that the extracellular protein, primarily hemoglobin, is oxidized leading to the formation of aggregates.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"20 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223024","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}

{"title":"Tuning the thermal conductivity of silicon nanowires by surface passivation","authors":"Céline Ruscher, Robinson Cortes-Huerto, Robert Hannebauer, Debashish Mukherji, Alireza Nojeh, A Srikantha Phani","doi":"10.1088/1361-6463/ad6fae","DOIUrl":"https://doi.org/10.1088/1361-6463/ad6fae","url":null,"abstract":"Using large scale molecular dynamics simulations, we study the thermal conductivity of bare and surface passivated silicon nanowires (SiNWs). For the cross–sectional widths <inline-formula>\u0000<tex-math><?CDATA $w unicode{x2A7D} 2$?></tex-math><mml:math overflow=\"scroll\"><mml:mrow><mml:mi>w</mml:mi><mml:mtext>⩽</mml:mtext><mml:mn>2</mml:mn></mml:mrow></mml:math><inline-graphic xlink:href=\"dad6faeieqn1.gif\"></inline-graphic></inline-formula> nm, SiNWs become unstable because of the surface amorphization and also due to the evaporation of a certain fraction of Si atoms. The observed surface (in–)stability is related to a large excess energy Δ of the surface Si atoms with respect to the bulk Si, resulting from the surface atoms being less coordinated and having dangling bonds. We first propose a practically relevant method that uses Δ as a guiding tool to passivate these dangling bonds with hydrogen or oxygen, stabilizing the SiNWs. These passivated SiNWs are used to calculate the thermal conductivity coefficient <italic toggle=\"yes\">κ</italic>. While the expected trend of <inline-formula>\u0000<tex-math><?CDATA $kappa propto w$?></tex-math><mml:math overflow=\"scroll\"><mml:mrow><mml:mi>κ</mml:mi><mml:mo>∝</mml:mo><mml:mi>w</mml:mi></mml:mrow></mml:math><inline-graphic xlink:href=\"dad6faeieqn2.gif\"></inline-graphic></inline-formula> is observed for all SiNWs, surface passivation provides an added flexibility of tuning <italic toggle=\"yes\">κ</italic> with the surface coverage concentration <italic toggle=\"yes\">c</italic> of passivated atoms. Indeed, with respect to the bulk <italic toggle=\"yes\">κ</italic>, passivation of SiNW reduces <italic toggle=\"yes\">κ</italic> by 75%–80% for <inline-formula>\u0000<tex-math><?CDATA $c to 50%$?></tex-math><mml:math overflow=\"scroll\"><mml:mrow><mml:mi>c</mml:mi><mml:mo accent=\"false\" stretchy=\"false\">→</mml:mo><mml:mn>50</mml:mn><mml:mi mathvariant=\"normal\">%</mml:mi></mml:mrow></mml:math><inline-graphic xlink:href=\"dad6faeieqn3.gif\"></inline-graphic></inline-formula> and increases it by 50% for the fully passivated samples. Analyzing the phonon band structures via spectral energy density, we discuss separate contributions from the surface and the core to <italic toggle=\"yes\">κ</italic>. Our results also reveal that surface passivation increases SiNW stiffness, contributing to the tunability in <italic toggle=\"yes\">κ</italic>.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"11 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223022","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}

{"title":"A high-performance microwave plasma source employing dielectric wedges","authors":"Fengming Yang, Wencong Zhang, Kama Huang, Yang Yang, Huacheng Zhu","doi":"10.1088/1361-6463/ad7148","DOIUrl":"https://doi.org/10.1088/1361-6463/ad7148","url":null,"abstract":"The microwave-to-plasma energy conversion efficiency and the ease of plasma self-ignition are critical factors affecting the applications for microwave plasma sources (MPSs). This study presents a novel MPS utilizing dielectric wedges for self-ignition and improved energy conversion. Firstly, we crafted a dielectric wedge with a gradient refractive index, guiding the electric field from air to dielectric materials and facilitating microwave propagation along the dielectric in a waveguide. Through electromagnetic simulation, we explored how the size and permittivity of the dielectric wedge affect the electric field distribution. Then, the MPS based on the dielectric wedge was designed. In this configuration, a dielectric tube encloses the discharge tube, connecting to dielectric wedges to guide electromagnetic waves to the plasma. We analyzed the MPS performance using the Drude model, evaluating microwave energy conversion efficiency across various electron densities and collision frequencies. The results were compared with a commonly used MPS based on a tapered waveguide, demonstrating the proposed MPS has wider applicability across different operation conditions. Finally, experiments under low pressures were conducted using various gases, showing an average energy conversion efficiency of approximately 40% higher than the tapered waveguide MPS. The experiments also indicate the proposed MPS has a greater capability of self-ignition at lower power levels. These findings highlight the efficacy of incorporating dielectric wedges to enhance MPS performance, making it conducive for broader industrial applications.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"438 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223060","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}

{"title":"Simulation study on electrical tree propagation under electrical and mechanical stresses","authors":"Hucheng Liang, Boxue Du","doi":"10.1088/1361-6463/ad7152","DOIUrl":"https://doi.org/10.1088/1361-6463/ad7152","url":null,"abstract":"Epoxy insulators in gas-insulated power apparatus are subjected to the combined effects of electrical and mechanical loads. In this work, a simulation model is built based on the energy theory to explore the electrical tree growth of epoxy resin under tensile and compressive stresses. With increasing AC voltage, the electrical tree growth is promoted, exhibiting a morphology with more branches. Tensile stress accelerates the electrical tree growth, while proper compressive stress has the opposite effect. However, when the compressive stress exceeds a certain value, electrical tree growth is promoted again. When the mechanical stress is vertical to the needle electrode, these effects primarily impact the length of the trees. Conversely, in parallel cases, mechanical stress mainly affects the width of the electrical trees. Filler doping play the role of obstacles as well as enhancing the electric field concentration, the electrical tree growth is firstly inhibited and then promoted as the doping content increases. The electrical tree morphologies of simulation and experiment are in good consistency, proving the reasonability of the simulation model.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"22 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223064","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}

{"title":"Effect characteristics of ANFs/SiO2 layer self-assembly on the insulation properties of aramid/epoxy composites","authors":"Jun Xie, Chengming Hu, Guowei Xia, Youzhi Zhang, Longyin Qiao, Bobin Xu, Xiaoyu Shi, Qing Xie","doi":"10.1088/1361-6463/ad714d","DOIUrl":"https://doi.org/10.1088/1361-6463/ad714d","url":null,"abstract":"Aramid fiber (AF)-reinforced epoxy (EP) resin composite materials are widely used in the application of insulation rod-reinforced components, but the adhesion performance between AFs and EP resin is poor, which easily leads to interfacial defects and even gradually develops into breakdown, flashover, and other faults. In this study, a simple, environmentally friendly, diverse, and highly designable layer-by-layer self-assembly modification method was adopted to assemble aramid nanofibers/SiO₂ onto the surface of AFs. The modified AFs were then used to produce composite materials with EP resin. By testing the interface breakdown, flashover, and leakage current of the AF/EP resin composite materials, the influence mechanism of AF surface modification on the material interface insulation performance was studied. The results show that the insulation performance of the modified composite material first increases and then decreases with the increase in the number of assembled layers, with the maximum increase in breakdown voltage being 93.56% and the maximum increase in flashover voltage being 30.91%.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"61 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223065","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}