Vacuum最新文献

{"title":"Molecular dynamics simulations of the evolution of primary radiation damage in Ti-6Ta alloy for spent nuclear fuel reprocessing","authors":"Huan Li ,&nbsp;Bohai Yang ,&nbsp;Jianping Xu ,&nbsp;Jinping Wu ,&nbsp;Zhenzhi Chen ,&nbsp;Junjie Wang","doi":"10.1016/j.vacuum.2025.114259","DOIUrl":"10.1016/j.vacuum.2025.114259","url":null,"abstract":"<div><div>Ti-6Ta (in wt%) alloy is extensively used in critical components for nuclear spent fuel reprocessing due to its excellent mechanical and resistance to boiling nitric acid corrosion properties. However, the study of defect formation and evolution mechanisms under irradiation conditions is still limited. This study employs molecular dynamics simulations to investigate the evolution of irradiation damage in Ti-6Ta alloy and compares its irradiation resistance mechanisms with those of pure Ti. Isothermal and differential temperature simulations were performed on primary knock-on atom with energies ranging from 1 to 20 keV to understand the irradiation resistance of Ti-6Ta alloy. During the thermal peak stage, Ti-6Ta alloy exhibits a higher number of displaced atoms, but fewer surviving defects after relaxation and recombination. After irradiation stabilization, Ti-6Ta alloy is less likely to form large defect clusters, and Ta atoms tend to appear in these larger clusters. As the temperature increases, tantalum atoms gradually appear in the defect clusters of the low Primary Knock-on Atom (PKA) energy system. Elevated temperatures enhance defect recombination rates and further reduce the migration effects of irradiation-induced defects.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"238 ","pages":"Article 114259"},"PeriodicalIF":3.8,"publicationDate":"2025-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143687437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rarefied gas flows in complex microfluidic 3D-structures fabricated via additive manufacturing","authors":"Franz Schweizer ,&nbsp;Klaus Bade ,&nbsp;Lucien Baldas ,&nbsp;Samuel Bergdolt ,&nbsp;Stéphane Colin ,&nbsp;Celine Deutschbein ,&nbsp;Stefan Hengsbach ,&nbsp;Jan G. Korvink ,&nbsp;Marcos Rojas-Cárdenas ,&nbsp;Jürgen J. Brandner","doi":"10.1016/j.vacuum.2025.114213","DOIUrl":"10.1016/j.vacuum.2025.114213","url":null,"abstract":"<div><div>In this work, two-photon-polymerization (TPP) is introduced as a method for manufacturing three-dimensional devices for rarefied gas flow applications. The novel 3D manufacturing capabilities of TPP are demonstrated by the fabrication of a microfluidic structure that consists of a circular micro-tube with a varying radius (tapered channel). The micro-tube has interesting features, such as a conical structure with one order of magnitude difference between minimum and maximum radii, that is <span><math><mrow><mn>14</mn><mspace></mspace><mi>μ</mi><mi>m</mi></mrow></math></span> and <span><math><mrow><mn>215</mn><mspace></mspace><mi>μ</mi><mi>m</mi></mrow></math></span>, respectively, and a very high aspect ratio, that is defined as the length over the minimum radius, of 72.3. To our knowledge, this is the first time that such a geometrical configuration has been successfully tested for rarefied gas flow applications. It supports the suitability of the presented fabrication method for further 3D new-generation applications in the field. The geometrical characteristics of the device were measured by <span><math><mi>μ</mi></math></span>-tomography and subsequently analyzed allowing the assessment of the geometrical precision of the fabrication method. From a fluid dynamics perspective, the device was tested by imposing pressure-driven gas flows in the converging and diverging directions of the structure for a wide range of rarefaction. The flow parameters linked to the structure, such as mass flow rates and conductances, were obtained experimentally using the constant volume technique. The experimental results were compared to numerical simulations obtained via Computational Fluid Dynamics solving the Navier–Stokes equation in the slip and hydrodynamic flow regimes. The experimental vs. numerical comparison showed good agreement within geometrical uncertainty.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"238 ","pages":"Article 114213"},"PeriodicalIF":3.8,"publicationDate":"2025-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143686967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microstructure evolution and strengthening mechanism of Al2O3/Kovar joints brazed with TiB enhanced Ag-Cu-Ti based composite fillers","authors":"Guo-Fu Ma ,&nbsp;Xiao-Qiang Li ,&nbsp;Qi Jiang ,&nbsp;De-Zhi Zhu ,&nbsp;Chao Yang","doi":"10.1016/j.vacuum.2025.114241","DOIUrl":"10.1016/j.vacuum.2025.114241","url":null,"abstract":"<div><div>This paper achieved reliable joining of Al₂O₃ ceramics and Kovar alloys using Ag-Cu-Ti single filler and Ag-Cu-Ti + B composite filler. The synergistic effect of Ti and B on phase formation and the mechanical properties of the Al₂O₃/Kovar joints was systematically investigated. By optimizing the B content and brazing parameters, the typical interfacial structure of the joints obtained using Ag-Cu-6Ti+0.5B (wt.%) composite filler at 880 °C for 10 min was identified as Al₂O₃/Ti₃Cu₃O/Ag(s,s) + Cu(s,s) + TiCu + TiB/Fe₂Ti + Ni₃Ti/Ag(s,s) + Cu(s,s) + Fe₂Ti/Kovar. The results showed that B addition refines the joint microstructure by forming fine TiB whiskers and partially inhibits the dissolution and diffusion of alloying elements from the Kovar side. The joints brazed with the Ag-Cu-6Ti + 0.5B (wt.%) composite filler at 880 °C/10 min achieved a maximum shear strength of 131 MPa, representing a 37 % increase compared to the joints brazed with the Ag-Cu-6Ti (wt.%) single filler. The enhancement was attributed to the refinement of the joint microstructure and the alleviation of residual stresses. Additionally, the fracture analysis of the joints containing B revealed the dendritic Ag-Cu eutectic structure and extensive presence of the reactive layer Ti₃Cu₃O, offering new insights into the failure mechanism of brazed ceramic/metal joints.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"238 ","pages":"Article 114241"},"PeriodicalIF":3.8,"publicationDate":"2025-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143686971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ultrathin g-C3N5 nanosheets: A sustainable metal-free photocatalyst for efficient ciprofloxacin degradation","authors":"Thangapandi Chellapandi ,&nbsp;Muthukani Elamathi","doi":"10.1016/j.vacuum.2025.114256","DOIUrl":"10.1016/j.vacuum.2025.114256","url":null,"abstract":"<div><div>Two-dimensional nanomaterials possess unique electrical, mechanical, and catalytic properties, primarily attributed to their high surface-to-volume ratio and exceptional light absorption capabilities. However, developing simple and efficient methods for synthesizing 2D nanosheets remains a significant challenge. This study presents a facile and effective strategy for the synthesis of ultrathin 2D g-C₃N₅ nanosheets through thermal polymerization and ultrasonication-assisted exfoliation technique. The almost total elimination of ciprofloxacin could be accomplished within 1.5 h, with a rate constant of 0.0286 min⁻¹. The synthesized nanosheets were meticulously characterized for their structural and morphological properties through a variety of analytical techniques. TEM confirmed its ultrathin layered structure, while XRD, FT-IR, and XPS provided comprehensive insights into their elemental composition. The improved photocatalytic activity of ultrathin 2D g-C₃N₅ nanosheets is primarily related to the increase in visible light absorption and electron–hole separation, as this was demonstrated by many distinct characterizations.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"238 ","pages":"Article 114256"},"PeriodicalIF":3.8,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143687428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of vacuum arc modes in 252 kV single-break vacuum interrupters based on deep learning image recognition","authors":"Siyuan Liu,&nbsp;Xianglai Bo,&nbsp;Jinchao Chen,&nbsp;Zhiyuan Liu,&nbsp;Yingsan Geng","doi":"10.1016/j.vacuum.2025.114258","DOIUrl":"10.1016/j.vacuum.2025.114258","url":null,"abstract":"<div><div>Replacing traditional SF₆ circuit breakers with environmentally friendly 252 kV single-break vacuum circuit breakers effectively reduce SF₆ greenhouse gas emissions in transmission systems. Understanding the evolution of vacuum arc modes under different conditions is crucial for analyzing 252 kV single-break vacuum interruption. This paper built a test platform using a detachable vacuum chamber and a motor-driven operating mechanism to investigate the vacuum arc modes of a 252 kV single-break vacuum interrupter with 2/3-turn coil-type axial magnetic field contacts under varying arc currents. The arc modes were classified, and a deep learning network was developed for arc mode image recognition. The results revealed the evolution characteristics of vacuum arc modes at a hundred-millimeter range contact gap and demonstrated the influence of arc current from 10 kA to 45 kA on the duration of arc modes.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"238 ","pages":"Article 114258"},"PeriodicalIF":3.8,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143716145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deficient MoO2 facilitating photothermal synergetic catalytic CO2 reduction selectively to CO over P-doped g-C3N4","authors":"Hailong Cao ,&nbsp;Fengyun Su ,&nbsp;Linbo Wang ,&nbsp;Yezhen Zhang ,&nbsp;Yonghao Xiao ,&nbsp;Xiaoli Jin ,&nbsp;Xin Li ,&nbsp;Haiquan Xie","doi":"10.1016/j.vacuum.2025.114262","DOIUrl":"10.1016/j.vacuum.2025.114262","url":null,"abstract":"<div><div>Photocatalytic conversion of CO₂ into fuels is considered a promising solution to the climate crisis and fossil fuel depletion. However, most photocatalysts exhibit low CO₂ reduction performance because of poor carrier separation, limited light absorption, or insufficient surface active sites. In this study, we fabricated a direct Z-scheme heterojunction (<em>X</em>-MoO₂/PCN) using oxygen-deficient molybdenum dioxide (MoO₂) and phosphorus-doped graphitic carbon nitride (PCN). Phosphorus doping enhances light absorption of g-C₃N₄ (CN), while the localized surface plasmon resonance (LSPR) effect in oxygen-deficient MoO₂ activates photothermal synergistic catalysis. The heterojunction also facilitates efficient separation of photogenerated carriers. The optimized 15 %-MoO₂/PCN composite exhibited yield of CO and CH₄ up to 92.11 μmol/g/h and 0.85 μmol/g/h under Uv–Vis-IR irradiation with a CO selectivity highly to 99.10 %, higher than most of the reported g-C₃N₄-based materials. This work provided a novel approach towards the rational design of a Z-scheme heterojunction for efficient photothermal CO₂ reduction.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"238 ","pages":"Article 114262"},"PeriodicalIF":3.8,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143687438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modulated electrical transport properties and enhanced thermoelectric performance in tellurium by compositing with copper and doping with antimony","authors":"Qiang Hu ,&nbsp;Manman Yang ,&nbsp;Xubiao Zhou ,&nbsp;Shangsheng Li ,&nbsp;Qinshan Liu ,&nbsp;Hongyu Zhu ,&nbsp;Taichao Su","doi":"10.1016/j.vacuum.2025.114249","DOIUrl":"10.1016/j.vacuum.2025.114249","url":null,"abstract":"<div><div>As we know, excellent electrical transport performance is essential for outstanding thermoelectric materials. To date, although commonly used doping strategy can optimize the carrier concentration, which also impact the carrier mobility and thus limit the improvement of thermoelectric performance. In this work, we have incorporated the highly conductive secondary phases of Cu into the Te matrix, specifically targeting an improvement in carrier mobility. It is delightful to report that we have successfully elevated the carrier mobility of Te from 186.9 to 372.6 cm²V⁻¹s⁻¹, and the electrical resistivity was significantly reduced. Furthermore, we have also conducted Cu compositing on the basis of carrier concentration optimization by Sb doping. It reveals that the combination of Cu compositing and Sb doping can further decreases the electrical resistivity by collaboratively optimizing the carrier mobility and carrier concentration. Additionally, the presence of Cu as highly conductive secondary phases within the matrix helps to filter the low-energy electrons and enhance the Seebeck coefficient effectively. Ultimately, we achieved a peak <em>zT</em> of ∼0.82 at 607 K for Te_0.994Cu_0.003Sb_0.003. This research provides a new direction for enhancing the performance of Te-based thermoelectric materials.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"238 ","pages":"Article 114249"},"PeriodicalIF":3.8,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143687442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Photocatalytic activity of CuBi2O4/CuO heterojunction for methylene blue degradation under visible light irradiation","authors":"Aminah Umar ,&nbsp;Cindy Claudia ,&nbsp;Munawar Khalil ,&nbsp;Ridla Bakri ,&nbsp;Hyung Bin Bae ,&nbsp;Kim Tae-Hwan ,&nbsp;Dewangga Oky Bagus Apriandanu","doi":"10.1016/j.vacuum.2025.114246","DOIUrl":"10.1016/j.vacuum.2025.114246","url":null,"abstract":"<div><div>We successfully synthesized CuBi₂O₄/CuO heterojunction with various mass ratios using a simple grinding-annealing method. The synthesized materials exhibited optical band gap values around 1.70 eV, suggesting their capability to absorb visible light. CuBi₂O₄/CuO was synthesized using mass ratios of 1:1, 1:2, and 2:1, which are referred to as CuBi₂O₄/CuO I, CuBi₂O₄/CuO II, and CuBi₂O₄/CuO III, respectively. The photocatalytic efficacy of CuBi₂O₄/CuO was evaluated for methylene blue degradation. Among the various mass ratios of CuBi₂O₄/CuO that were tested, CuBi₂O₄/CuO II exhibited the highest photocatalytic degradation efficiency (81.1 %) when subjected to visible light within 180 min. HR-TEM analysis validated the heterojunction formation of CuBi₂O₄/CuO between CuBi₂O₄ and CuO. Utilizing an adequate quantity of CuBi₂O₄ and CuO at a mass ratio 1:2, produces a synergistic effect in the heterojunction system of exceptional superiority. This work examines how the CuBi₂O₄/CuO mass ratio affects the breakdown of organic pollutants under visible light exposure.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"238 ","pages":"Article 114246"},"PeriodicalIF":3.8,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143687439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on optimizing the microstructures and properties of 50 wt% Si particle-reinforced Al matrix composites for electronic packaging based on the synergistic action of sub-rapid solidification and deformation strengthening","authors":"Tao Jiang ,&nbsp;Hongyang Zhao ,&nbsp;Yong Li ,&nbsp;Wei Yu ,&nbsp;Wanshun Zhang ,&nbsp;Yonghui Sun ,&nbsp;Zhaodong Wang","doi":"10.1016/j.vacuum.2025.114260","DOIUrl":"10.1016/j.vacuum.2025.114260","url":null,"abstract":"<div><div>In this work, we employed techniques based on the synergistic manufacturing strategy of sub-rapid solidification and deformation strengthening. Subsequently, we solved the issue of poor plastic deformation in Sip/Al composites and enhanced the microstructures and properties of such materials. The experimental results revealed that the solidified microstructure of the roll-cast composite was significantly more refined than the as-cast composite, with a 75.7 % reduction in the Si particle size. This remarkable microstructural optimization was the result of the multiple synergistic effects of the plastic deformation mechanism. Advanced characterization methods such as large-area electron backscatter diffraction stitching and transmission Kikuchi diffraction were used to reveal this potential microstructure-property response mechanism. In this study, we propose a novel strategy for overcoming challenges and optimizing performance in the plastic processing of Sip/Al composites, thereby laying a theoretical and experimental foundation for broadening the application of such materials.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"238 ","pages":"Article 114260"},"PeriodicalIF":3.8,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143631893","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Swift heavy ion irradiation of polycrystalline SiC pre-implanted with silver ions at room temperature: Effects of swift heavy ion fluence","authors":"Z.A.Y. Abdalla ,&nbsp;R.E. Chauke ,&nbsp;V.A. Skuratov ,&nbsp;T.T. Hlatshwayo","doi":"10.1016/j.vacuum.2025.114257","DOIUrl":"10.1016/j.vacuum.2025.114257","url":null,"abstract":"<div><div>This study investigates the effects of SHIs irradiation fluence on the recrystallization and structural evolution of amorphous SiC layer induced by ion implantation. Polycrystalline SiC wafers were implanted with 360 keV Ag ions to a fluence of 2 × 10¹⁶ cm⁻² at room temperature. Some of the pre-implanted samples were then irradiated at room temperature with 167 MeV Xe ions to fluences of 1 × 10¹³ cm⁻², 1 × 10¹⁴ cm⁻², 3.4 × 10¹⁴ cm⁻² and 8.4 × 10¹⁴ cm⁻². The samples were then characterized using Transmission Electron Microscopy (TEM), Raman Spectroscopy, and Rutherford Backscattering Spectrometry (RBS). Ag implantation resulted in the amorphization of SiC from the surface to a depth of 270 nm. SHIs irradiation at a fluence of 1 × 10¹³ cm⁻² reduced the amorphous layer thickness to 230 nm, which represents a 15 % reduction. This was accompanied with a partial recrystallization in the amorphous layer. A similar reduction of approximately 15 % was observed at fluences of 1 × 10¹⁴ cm⁻² and 3.4 × 10¹⁴ cm⁻². While, irradiation at 8.4 × 10¹⁴ cm⁻² reduced the amorphous layer to 220 nm, which represents a 19 % reduction. The results showed that the degree of crystallization within the amorphous layer gradually increased with irradiation fluences of SHIs, indicating that recrystallization is fluence-dependent. No migration of pre-implanted Ag was observed after SHIs irradiation.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"238 ","pages":"Article 114257"},"PeriodicalIF":3.8,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143628566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}