Journal of Physics D: Applied Physics最新文献

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In-situ and ex-situ characterizations of PVT-grown 4H-SiC single crystals PVT 生长的 4H-SiC 单晶的原位和离位表征
IF 3.4 3区 物理与天体物理
Journal of Physics D: Applied Physics Pub Date : 2024-09-03 DOI: 10.1088/1361-6463/ad7149
Qinqin Shao, Ruohan Shen, He Tian, Xiaodong Pi, Deren Yang, Rong Wang
{"title":"In-situ and ex-situ characterizations of PVT-grown 4H-SiC single crystals","authors":"Qinqin Shao, Ruohan Shen, He Tian, Xiaodong Pi, Deren Yang, Rong Wang","doi":"10.1088/1361-6463/ad7149","DOIUrl":"https://doi.org/10.1088/1361-6463/ad7149","url":null,"abstract":"4H silicon carbide (4H-SiC) is one of the most promising candidates in high-power and high-frequency devices, owing to its excellent properties such as wide bandgap, high electron mobility, high electric breakdown field and high thermal conductivity. The physical-vapor-transport (PVT) approach has been broadly adopted to grow 4H-SiC single-crystal boules. Because of the high-temperature growth of 4H-SiC single-crystal boules, the PVT system is a ‘black-box’ system, which decreases the yield and thus increases the cost of 4H-SiC single-crystals. Although advanced modern characterization tools, e.g. atomic force microscopy, <italic toggle=\"yes\">x</italic>-ray topography, x-ray diffraction and Raman scattering spectroscopy, can provide deep insight into the structural and defect properties of 4H-SiC boules, it is rather limited to gain <italic toggle=\"yes\">in-situ</italic> information of the growth process by these <italic toggle=\"yes\">ex-situ</italic> methods. Therefore, the <italic toggle=\"yes\">in-situ</italic> visualization on the evolution of structural morphologies and defects conducted by <italic toggle=\"yes\">x</italic>-ray computed tomography (<italic toggle=\"yes\">x</italic>CT) is of great importance for further development. In this topical review, the application of the <italic toggle=\"yes\">x</italic>CT technology on the <italic toggle=\"yes\">in-situ</italic> visualization of the evolution of the growth front, growth rate, defects, and the mass transport of the source material of 4H-SiC are reviewed. The <italic toggle=\"yes\">ex-situ</italic> characterization of 4H-SiC single-crystal boules are also briefly introduced. This topical review provides insight into the growth process, structural morphology, and defect evolution of PVT-grown 4H-SiC single-crystal boules.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"29 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223017","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}
引用次数: 0
Recent advances in molecular dynamics simulations for dry friction on rough substrate 粗糙基底干摩擦分子动力学模拟的最新进展
IF 3.4 3区 物理与天体物理
Journal of Physics D: Applied Physics Pub Date : 2024-09-03 DOI: 10.1088/1361-6463/ad6e00
Yan Zhang, Zhaofu Zhang, Yuzheng Guo, John Robertson, Shijing Wu, Sheng Liu, Yunyun Sun
{"title":"Recent advances in molecular dynamics simulations for dry friction on rough substrate","authors":"Yan Zhang, Zhaofu Zhang, Yuzheng Guo, John Robertson, Shijing Wu, Sheng Liu, Yunyun Sun","doi":"10.1088/1361-6463/ad6e00","DOIUrl":"https://doi.org/10.1088/1361-6463/ad6e00","url":null,"abstract":"This review provides a comprehensive overview of recent advancements in molecular dynamics (MD) simulations of dry friction on rough substrates. While nanoscale roughness plays a crucial role in nanotribological investigations, the exploration of rough substrates remains insufficient based on MD simulations. This paper summarizes research on rough surfaces constructed from various descriptions, including the multi-asperity surface, groove-textured surface, fractal surface, Gaussian surface, stepped surface and randomly rough surface. In addition, the friction behavior of rough substrates coated with solid films is comprehensively elucidated. Present investigations on rough surfaces primarily focus on the effect of basic frictional variables, surface morphology characteristics and different motion types. The studies conducted on rough substrates exhibit a higher degree of resemblance to realistic interfaces, thereby offering valuable insight into the design of surface morphology to achieve enhanced frictional performance.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"4 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223015","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}
引用次数: 0
Single-crystal silicon ablation with temporally delayed femtosecond laser double-pulse trains 利用时延飞秒激光双脉冲序列烧蚀单晶硅
IF 3.4 3区 物理与天体物理
Journal of Physics D: Applied Physics Pub Date : 2024-09-03 DOI: 10.1088/1361-6463/ad7300
Zhengjie Fan, Liangtian Yi, Jing Lv, Wenjun Wang, Guoji Li, Jianlei Cui
{"title":"Single-crystal silicon ablation with temporally delayed femtosecond laser double-pulse trains","authors":"Zhengjie Fan, Liangtian Yi, Jing Lv, Wenjun Wang, Guoji Li, Jianlei Cui","doi":"10.1088/1361-6463/ad7300","DOIUrl":"https://doi.org/10.1088/1361-6463/ad7300","url":null,"abstract":"A double-pulse femtosecond laser is used to process single-crystal silicon. Modulating the delay time was discovered to increase the ablation depth and improve the morphology of the ablated surface. The hole fabricated by a dual-pulse with a 200 ps interval is 24.4% deeper than that created by a single pulse of the same energy. Moreover, utilizing a dual pulse with an interval ranging from 100 to 1000 ps produces a considerably smoother ablation area as compared to the single pulse. The effect of the sub-pulse energy ratio of the double-pulse femtosecond laser on the size and morphology of the ablated area was also investigated. As the sub-pulse energy ratio decreases from 3:1 to 1:3, the size of the ablation area initially decreases and then increases, while the size of the ablation area is minimized when the sub-pulse ratio is 1:1, enabling precise control over the machining size. As the energy of the second sub-pulse increases, the ablation area becomes smoother due to the plasma heating of the double-pulse femtosecond laser.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"9 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223018","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}
引用次数: 0
Light-induced fading effects on TL and OSL signals and feasibility of dose re-assessment with PTTL signals in BeO dosimeters 光诱导衰减对 TL 和 OSL 信号的影响以及在 BeO 辐射计中使用 PTTL 信号进行剂量再评估的可行性
IF 3.4 3区 物理与天体物理
Journal of Physics D: Applied Physics Pub Date : 2024-09-03 DOI: 10.1088/1361-6463/ad6fb2
Engin Aşlar
{"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}
引用次数: 0
Low-current gliding DC discharge in high-speed flows 高速水流中的低电流滑行直流放电
IF 3.4 3区 物理与天体物理
Journal of Physics D: Applied Physics Pub Date : 2024-09-02 DOI: 10.1088/1361-6463/ad726e
K N Kornev, A A Logunov, S A Dvinin
{"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<sup>−1</sup> 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><sub>e</sub> ∼ 10<sup>14</sup> cm<sup>−3</sup> and the plasma ionization degree were determined by measuring the Stark broadening of the hydrogen H<italic toggle=\"yes\"><sub>β</sub></italic> line (<italic toggle=\"yes\">λ</italic><sub>H<italic toggle=\"yes\">β</italic></sub> = 486.1 nm). The estimates of the electric field (<italic toggle=\"yes\">E</italic> ∼ 100 V cm <sup>−1</sup> ÷ 600 V cm<sup>−1</sup>) 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><sub>g</sub> = 7000–9500 K and the vibrational temperature <italic toggle=\"yes\">T</italic><sub>v</sub> = 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, N<sub>2</sub><sup>+</sup>, 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}
引用次数: 0
Silicon-based perovskite plasmonic diode with highly polarized emission 具有高度偏振发射的硅基过氧化物质子二极管
IF 3.4 3区 物理与天体物理
Journal of Physics D: Applied Physics Pub Date : 2024-09-02 DOI: 10.1088/1361-6463/ad7037
Xin-Rui Mao, Zihao Chu, Xiaogen Yi, Riyu Cong, Yanping Li, Wanjin Xu, Guangzhao Ran
{"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 SiO<sub>2</sub> 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}
引用次数: 0
Importance of gas heating in capacitively coupled radiofrequency plasma-assisted synthesis of carbon nanomaterials 气体加热在电容耦合射频等离子体辅助合成碳纳米材料中的重要性
IF 3.4 3区 物理与天体物理
Journal of Physics D: Applied Physics Pub Date : 2024-08-30 DOI: 10.1088/1361-6463/ad6d78
Tanvi Nikhar, Sankhadeep Basu, Shota Abe, Shurik Yatom, Yevgeny Raitses, Rebecca Anthony, Sergey V Baryshev
{"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 C<sub>2</sub> 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><sup>3</sup> formation: characterized by much lower reaction rates, when compared to <italic toggle=\"yes\">sp</italic><sup>2</sup>, <italic toggle=\"yes\">sp</italic><sup>3</sup> formation kinetics are expected to become exponentially slow. This result was further confirmed by experiments under identical conditions but with a H<sub>2</sub>/CH<sub>4</sub> mixture, where no output material was detected: if graphitic <italic toggle=\"yes\">sp</italic><sup>2</sup> 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><sup>2</sup>-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><sup>3</sup> production was attained with H<sub>2</sub>/CH<sub>4</sub> 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}
引用次数: 0
Discharge fault type identification of C4F7N/CO2/O2 mixed insulating gas for engineering based on product components 根据产品成分识别工程用 C4F7N/CO2/O2 混合绝缘气体的放电故障类型
IF 3.4 3区 物理与天体物理
Journal of Physics D: Applied Physics Pub Date : 2024-08-30 DOI: 10.1088/1361-6463/ad714c
Guangkai Cui, Cong Wang, Yuan Yang, Hao Wang, Youping Tu, Zhong Zheng, Hua Jin
{"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 (C<sub>4</sub>F<sub>7</sub>N) gas mixture is considered one of the most promising alternative gases for SF<sub>6</sub> due to its excellent environmental protection and insulation performance. At present, the Shanghai region of China has adopted 8.5% C<sub>4</sub>F<sub>7</sub>N-86% CO<sub>2</sub>-5.5% O<sub>2</sub> 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 C<sub>4</sub>F<sub>7</sub>N/CO<sub>2</sub>/O<sub>2</sub> gas mixture under discharge faults mainly include CO, CF<sub>4</sub>, C<sub>3</sub>F<sub>8</sub>, C<sub>4</sub>F<sub>8</sub>, C<sub>3</sub>F<sub>6</sub>, and CF<sub>3</sub>CN. According to the decomposition path of the C<sub>4</sub>F<sub>7</sub>N gas mixture, this paper selected three primary decomposition products (CO, CF<sub>4</sub>, C<sub>3</sub>F<sub>8</sub>) and one secondary decomposition product (C<sub>4</sub>F<sub>8</sub>) for the correlation characterization of discharge types, and proposed the ratios of c(CO)/c(CF<sub>4</sub>) and c(C<sub>4</sub>F<sub>8</sub>)/c(C<sub>3</sub>F<sub>8</sub>) as the characteristic quantities to characterize the different discharge types. Finally, in order to accurately identify the C<sub>4</sub>F<sub>7</sub>N/CO<sub>2</sub>/O<sub>2</sub> 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 (CF<sub>4</sub>) and c (C<sub>4</sub>F<sub>8</sub>)/c (C<sub>3</sub>F<sub>8</sub>) 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}
引用次数: 0
Oxidative aggregation of hemoglobin–a mechanism for low-temperature plasma-mediated wound healing 血红蛋白的氧化聚集--低温血浆介导伤口愈合的机制
IF 3.4 3区 物理与天体物理
Journal of Physics D: Applied Physics Pub Date : 2024-08-30 DOI: 10.1088/1361-6463/ad6e99
Irina Oganesyan, Alina Begley, Dušan Mrđenović, Julian A Harrison, Renato Zenobi
{"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}
引用次数: 0
Tuning the thermal conductivity of silicon nanowires by surface passivation 通过表面钝化调节硅纳米线的热导率
IF 3.4 3区 物理与天体物理
Journal of Physics D: Applied Physics Pub Date : 2024-08-30 DOI: 10.1088/1361-6463/ad6fae
Céline Ruscher, Robinson Cortes-Huerto, Robert Hannebauer, Debashish Mukherji, Alireza Nojeh, A Srikantha Phani
{"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}
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