Vacuum最新文献

{"title":"Atomistic simulation of porous nanocrystalline NiTi shape memory alloy considering coupling effects of transformation and plasticity","authors":"Xiang Zhu ,&nbsp;Shihao Li ,&nbsp;Yaguang Wang ,&nbsp;Guansuo Dui","doi":"10.1016/j.vacuum.2025.114546","DOIUrl":"10.1016/j.vacuum.2025.114546","url":null,"abstract":"<div><div>Nanocrystalline NiTi alloy exhibits recoverable martensitic transformation and irrecoverable plastic deformation when subjected to sufficiently high stresses. Mechanical behaviors including superelasticity and plasticity of NiTi alter drastically with the change in its initial microstructure such as void and grain size. This work mainly focuses on investigating the coupling effects of transformation and plasticity as well as the grain size and porosity dependent superelastic-plastic responses of porous nanocrystalline NiTi by using molecular dynamics simulations. Results demonstrate that plastic deformation exerts a potent inhibitory influence on the reverse phase transformation from martensite to austenite. The mechanisms of the transformation-plasticity coupling and the generation of residual strain after unloading are revealed at the atomic level. The evolution of the microstructure manifests that the residual martensite due to partial reverse transformation and the dislocation inside the grains as well as the disordered structures at the interfaces make the contribution to the total residual strain. The concentration of plastic shear strain around the voids and on the grain boundaries indicates that grain-boundary sliding and stress concentration around the voids contribute significantly to the plastic deformation. Simulated results indicate that porosity and grain size exert significant effects on the superelastic-plastic behaviors.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"240 ","pages":"Article 114546"},"PeriodicalIF":3.8,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144514269","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":"ICP-RIE etching of MESA and trench SiC structures in SF6 + O2 plasma: significant difference in SiC etching rate dependence on oxygen content","authors":"K. Racka-Szmidt ,&nbsp;J. Żelazko ,&nbsp;P.P. Michałowski ,&nbsp;A. Roguska ,&nbsp;M. Pisarek ,&nbsp;A. Banasiak ,&nbsp;K. Przyborowska ,&nbsp;B. Stańczyk ,&nbsp;A. Harmasz ,&nbsp;M. Sochacki","doi":"10.1016/j.vacuum.2025.114543","DOIUrl":"10.1016/j.vacuum.2025.114543","url":null,"abstract":"<div><div>Silicon carbide (SiC) is an attractive semiconductor with many excellent properties that can bring huge potential advances in submicron semiconductor processing technology. The inductively coupled plasma reactive ion etching (ICP-RIE) method is widely used in the fabrication technology of various semiconductor devices. The paper presents the results of the ICP-RIE etching of SiC trench or MESA structures. The influence of O₂ addition to the SF₆ plasma on the etching process of these structures is reported. Etched SiC structures are studied by SIMS, SEM, XPS and stylus profilometry. It will be shown that MESA and trench structures have different dependences of the SiC etching rates depending on O₂ content. For trench structures, the initial decrease in the SiC etching rate under increased oxygen content is observed which differs from the trend of MESA dependences obtained in this work, and also reported in the literature. For both types of these structures, the paper presents a possible explanation of the difference in their characteristics of the SiC etching rate on the oxygen content in SF₆ + O₂ gas mixture.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"240 ","pages":"Article 114543"},"PeriodicalIF":3.8,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144510997","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":"Multi-strategy optimization model based on continuous cellular automaton and particle swarm optimization for controlling sputter etched profiles by focused ion beam","authors":"Xi Lin ,&nbsp;Haoyang Liu ,&nbsp;Xi Chen ,&nbsp;Ye Chen ,&nbsp;Yan Xing ,&nbsp;Zaifa Zhou ,&nbsp;Qing Chai","doi":"10.1016/j.vacuum.2025.114534","DOIUrl":"10.1016/j.vacuum.2025.114534","url":null,"abstract":"<div><div>With the development of micro-nano-scale devices, the precise manufacturing of complex topographies using focused ion beam (FIB) sputter etching has become an indispensable process requirement. The fabrication of curved micro-nano structures primarily employs bitmaps and stream files. However, due to the influence of complex effects, it is challenging to directly ascertain the process parameters. Therefore, this paper intensively analyzes the FIB manufacturing method, focusing specifically on the control methodology of bitmaps and stream files in the production of complex structures. Furthermore, the multi-strategy optimization model based on CCA-PSO (Continuous Cellular Automaton &amp; Particle Swarm Optimization) is proposed, integrating simulation and optimization techniques to acquire process parameters and enhance manufacturing accuracy. The model leverages the characteristics of FIB sputter etching, simplifying the solution space, optimizing the search method, and increasing the iteration rate. Additionally, various complex structure manufacturing experiments were designed to validate the model's effectiveness and rationality. The advantages and limitations of the optimization methods and the three strategies are elaborated in detail, and their application in real manufacturing scenarios is also discussed, providing a reference for the further application of FIB manufacturing technology.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"240 ","pages":"Article 114534"},"PeriodicalIF":3.8,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144518335","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":"Customized atmospheric pressure plasma polymerization process with an acrylic acid-based hybrid precursor on polylactic acid nonwoven for antibacterial scaffolds","authors":"Guo-Chung Dong ,&nbsp;Li-Chun Chang ,&nbsp;Liang-Jung Chien ,&nbsp;Ya-Jyun Liang ,&nbsp;Jyh-Wei Lee ,&nbsp;Feng-Huei Lin ,&nbsp;Wei-Yu Chen","doi":"10.1016/j.vacuum.2025.114537","DOIUrl":"10.1016/j.vacuum.2025.114537","url":null,"abstract":"<div><div>There is considerable interest in applying polylactic acid (PLA) nonwoven as a scaffold in biomaterials due to its porous structure, biodegradability, favourable mechanical properties and renewable nature. However, the chemically inert and hydrophobic surface of PLA limits its biocompatibility and poses challenges to improving its antibacterial ability through modification for inhibiting postoperative infection. In addition, PLA nonwoven is sensitive to most chemical methods for both functionalization and sterilisation. To tackle these issues without impairing PLA nonwovens, a tailored atmospheric pressure plasma (APP) system along with a hybrid precursor of acrylic acid and silver nitrate was designed and employed for surface functionalization. In this system, electrons and reactive species created during the APP process were utilised for reducing silver nanoparticles from the hybrid precursor. By performing APP polymerization and reduction simultaneously, we prepared a silver nanoparticle-embedded and carboxyl-rich polymerized film was prepared and deposited on the PLA nonwoven surface. This study presents a comprehensive analysis of the wettability, hydrophilicity stability, surface elemental composition, biocompatibility and antibacterial efficacy of the PLA nonwoven surface functionalized by the proposed APP method. Compared to conventional methods, this process is capable of immobilising a higher percentage of carboxyl functional groups with improved efficiency in enhancing antibacterial properties.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"240 ","pages":"Article 114537"},"PeriodicalIF":3.8,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144518332","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":"Optimizing and well-Controlled Grayscale Electron Beam lithography for planar dual-blazed grating fabrication","authors":"Liang Liu ,&nbsp;Xiaodong Zhang ,&nbsp;Jingyuan Zhu ,&nbsp;Siyu Dong ,&nbsp;Zeyong Wei ,&nbsp;Zhanshan Wang ,&nbsp;Xinbin Cheng","doi":"10.1016/j.vacuum.2025.114540","DOIUrl":"10.1016/j.vacuum.2025.114540","url":null,"abstract":"<div><div>The blazed grating is a commonly used spectral component in spectroscopic imaging systems, but its operating bandwidth is limited by diffraction efficiency. Dual-blazed gratings, with varying blazed angles in different regions, offer a solution for wider bandwidth. However, fabricating such gratings faces the challenges in processing different angles and matching wavefronts. Grayscale electron beam lithography (g-EBL) presents a flexible method for manufacturing dual-blazed gratings with high efficiency and precise wavefronts compared to other techniques. Despite its advantages, the detailed process remains underdiscussed. This paper outlines a detailed g-EBL process for creating planar dual-blazed gratings. By optimizing grating layout and exposure doses, two blazed-angle gratings (1.8° and 3.5°) were accurately produced with consistent alignment in center height. The resulting dual-blazed grating exhibited 53 % average diffraction efficiency in 0.4–1.05 μm and less than 0.2 wv Peak-to-Valley wavefront aberration. This method establishes a universal approach for crafting dual-blazed gratings using g-EBL techniques.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"240 ","pages":"Article 114540"},"PeriodicalIF":3.8,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144491578","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 growth mechanism of InAs array nanowires on two different patterned substrates","authors":"Xiaoye Wang ,&nbsp;Xiaoguang Yang ,&nbsp;Tao Yang","doi":"10.1016/j.vacuum.2025.114539","DOIUrl":"10.1016/j.vacuum.2025.114539","url":null,"abstract":"<div><div>Si/SiO₂ patterned substrates are usually employed to assist the positioning growth of array nanowires, but the detailed growth mechanism has not been thoroughly investigated. In this work, two completely different methods were adopted to fabricate Si/SiO₂ patterned substrates, and the InAs array nanowires grown on them via MOCVD presented some distinct growth results. By deeply analyzing the different processes and structures of the two methods for preparing patterned substrates, the different growth mechanisms of the two array nanowires were studied. Moreover, the method of preparing Si/SiO₂ patterned substrates using Si₃N₄ as a transition layer can further reduce the diameter of naonholes and solve the problem that the diameter of nanoholes of the Si/SiO₂ patterned substrates prepared by the traditional method is difficult to be further reduced.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"240 ","pages":"Article 114539"},"PeriodicalIF":3.8,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144472151","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":"Characterization of on-state resistance of electrically-triggered vacuum surface flashover switch","authors":"Yingjie Fu ,&nbsp;Bingyang Feng ,&nbsp;Mingtian Ye ,&nbsp;Luokang Dong ,&nbsp;Shenyi Qin ,&nbsp;Zhengzheng Liu ,&nbsp;Mengbing He","doi":"10.1016/j.vacuum.2025.114531","DOIUrl":"10.1016/j.vacuum.2025.114531","url":null,"abstract":"<div><div>The electrically triggered vacuum surface flashover switch (VSFS) has the advantages of high-speed conduction, fast insulation recovery, compact size, and simple construction, making it well-suited for high voltage and high-power conversion applications. The on-state resistance, as a critical parameter of the VSFS, directly influences the output efficiency and lifetime of the pulse power system. In this paper, a theoretical model of the VSFS on-state resistance is proposed, and the effect of different phases of channel development on the on-state resistance is also investigated. Specifically, it covers the channel expansion and channel resistivity decline during three distinct developmental phases, the establishment of vacuum-stream channel, the resistance collapse of vacuum-stream channel, and the on state. The theoretical model demonstrates that increasing the operating voltage can effectively expand the channel width, and the channel voltage in the on-state is negative to the channel resistivity. Finally, the variation trend of the VSFS on-state resistance under square wave and exponential decay conditions was calculated using experimental waveforms, and the experimental results are consistent with the theoretical analysis.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"240 ","pages":"Article 114531"},"PeriodicalIF":3.8,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144480862","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 metamagnetic transition in nanosized FeRh structures","authors":"A. Lengyel ,&nbsp;M.A. Gracheva ,&nbsp;A.I. Chumakov ,&nbsp;D. Bessas ,&nbsp;Sz Sajti ,&nbsp;A. Deák ,&nbsp;Z. Zolnai ,&nbsp;G.Z. Radnóczi ,&nbsp;Z.E. Horvath ,&nbsp;G. Hegedűs ,&nbsp;D.G. Merkel","doi":"10.1016/j.vacuum.2025.114533","DOIUrl":"10.1016/j.vacuum.2025.114533","url":null,"abstract":"<div><div>Nanosized iron-rhodium islands of various sizes have been successfully prepared on MgO substrate by masked molecular beam epitaxy. Nuclear scattering of nanofocused synchrotron radiation was used to map the islands, and in-situ measure their magnetic states and metamagnetic phase transition. The findings demonstrated a pronounced size dependency in the metamagnetic behavior of the FeRh, as the size of the islands decreased, the metamagnetic phase transition changes until finally it disappears completely at certain threshold size. This suppression effect suggests that finite-size scaling plays a significant role in determining the magnetic characteristics of FeRh at the nanoscale. These results provide insight into the fundamental mechanisms behind size-dependent magnetic phase transitions in FeRh nanostructures, which likely arise due to increased surface-to-volume ratios, altered atomic coordination, and oxidation-based effects.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"240 ","pages":"Article 114533"},"PeriodicalIF":3.8,"publicationDate":"2025-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144472152","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":"Vacuum system of the HEPS storage ring","authors":"Haiyi Dong,&nbsp;Ping He,&nbsp;Qi Li,&nbsp;Dizhou Guo,&nbsp;Xujian Wang,&nbsp;Yongsheng Ma,&nbsp;Baiqi Liu,&nbsp;Tao Huang,&nbsp;Lei Zhang,&nbsp;Fei Sun,&nbsp;Tianfeng Liu,&nbsp;Pilong Tian,&nbsp;Yuchen Yang,&nbsp;Qi Yang,&nbsp;Pengcheng Wang,&nbsp;Jiaming Liu,&nbsp;Shunming Liu,&nbsp;Xiaoyang Sun,&nbsp;Bangle Zhu,&nbsp;Biao Tan,&nbsp;Saike Tian","doi":"10.1016/j.vacuum.2025.114520","DOIUrl":"10.1016/j.vacuum.2025.114520","url":null,"abstract":"<div><div>HEPS (High Energy Photon Source) is a 4th generation ring-based light source with a beam energy of 6 GeV and a beam current intensity of 200 mA. The HEPS accelerator consists of a linac, a booster, a storage ring, and three transport lines connecting the linac, booster, and storage ring. The storage ring serves as the core region of HEPS. In this paper, the characteristics of the storage ring vacuum system are reviewed, and the designs and fabrication approaches for some key vacuum components are detailed. The main challenges include the extrusion of thin-walled CuCrZr vacuum chambers and the application of NEG (Non Evaporable Getters) coatings on their inner surfaces. These are used to mitigate substantial heat loads induced by synchrotron radiation along the vacuum chamber walls and provide an effective pumping speed for conductance-limited vacuum pipes with an inner diameter of 22 mm. The installation of the storage ring vacuum system started in November 2023, and finished in July 2024. Vacuum sectors were in-situ baked and activated for NEG films in the vacuum chambers, an average static pressure of 3 × 10⁻⁸Pa has been reached, which is better than the specification. These results confirm the feasibility of the storage ring vacuum system, covering aspects from the design and fabrication of components such as vacuum chambers, RF shielding bellows, and photon absorbers to processes like NEG coating via magnetron sputtering, installation, and in-situ activation of NEG films. After more than 20 days of conditioning, the beam current of the HEPS storage ring reached 12 mA, marking a milestone progress in the HEPS accelerator. At present, the accumulated beam dose is about 30 Ah (Jan.2025), the vacuum system performs well, the dynamic pressure of the storage ring is expected to decrease with the increase of accumulated beam dose.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"240 ","pages":"Article 114520"},"PeriodicalIF":3.8,"publicationDate":"2025-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144335648","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":"Aerodynamic heating distribution of the inner wall in an evacuated tube structure","authors":"Yongbao Wang ,&nbsp;Xiaolei Zhang ,&nbsp;Zhengyang Zhang ,&nbsp;Yunjing Nie ,&nbsp;Zhaoliang Li","doi":"10.1016/j.vacuum.2025.114530","DOIUrl":"10.1016/j.vacuum.2025.114530","url":null,"abstract":"<div><div>To investigate the distribution of Aerodynamic Heating (AH) on ultra-high-speed Evacuated Tube Structures (ETS), a 2D fluid simulation model utilizing the overset grid method was developed. The model comprehensively considered the internal track heat source and fluid-solid coupling heat transfer analysis. The distribution of AH on the inner wall was studied, taking into account various factors, including vacuum level, blocking ratio, train speed and operating time intervals. The results reveal that the radiation from the internal heat source can impact AH along the height of the ETS. Meanwhile, vacuum degree exhibit only limited effects on temperature rise in the tube. On the other hand, blocking ratio and train speed are identified as major factors significantly influencing AH, the residual temperature can rise 55 K. Furthermore, the number of train operations is a linear increasing with the residual temperature. If effective cooling measures are not implemented, the increased residual temperature can have an impact on the tube.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"240 ","pages":"Article 114530"},"PeriodicalIF":3.8,"publicationDate":"2025-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144491577","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}