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High-temperature long-term oxidation resistance of SiCf/SiC-TaB2 composites fabricated by organic-inorganic hybrid precursor infiltration and pyrolysis process

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Corrosion Science 2025年 254卷

作者： Lv, Haozhong Zhu, Shipeng Tang, Yilin Zhang, Boya Sun, Wenting Yang, Yunhua Li, Junping Li, Junning Ge, Min Zhang, Weigang Science and Technology on Advanced Functional Composites Laboratory Aerospace Research Institute of Materials & Processing Technology Beijing100076 China State Key Laboratory of Mesoscience and Engineering Institute of Process Engineering Chinese Academy of Sciences Beijing100190 China

As an ideal material for high-performance aeroengines, silicon carbide ceramic matrix composites (SiC-CMCs) still face challenges such as degradation due to high-temperature oxidation and limitations of traditional processing methods. In this study, the SiCf/SiC-TaB2 composites were fabricated using an organic-inorganic hybrid process combining precursor infiltration and pyrolysis (PIP) and slurry infiltration (SI) techniques. Analysis of both non-isothermal and isothermal oxidation behaviors revealed that the incorporation of TaB2 particles substantially improves the oxidation resistance of SiC-CMCs over a wide temperature range. Moreover, a critical finding is the structural evolution of Ta2O5, formed from the oxidation of TaB2, which transitions from grainy to flaky and eventually to a layered structure, significantly contributing to the composites' long-term oxidation resistance. Compared with the conventional SiCf/SiC composites, the mass change of the SiCf/SiC-TaB2 composites decreased by 34.8 %, 52.0 %, and 86.2 % after oxidation at 1200°C, 1300°C, and 1400°C for 100 hours, respectively. Meanwhile, the strength retention of the composites increased by 6.61 %, 13.90 %, and 6.87 % at these temperatures. These findings underscore the efficacy of the organic-inorganic hybrid precursor infiltration and pyrolysis process in producing high-performance SiC-CMCs with enhanced oxidation resistance and mechanical durability. © 2025 Elsevier Ltd

关键词： Organic-inorganic materials

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Influence of n = 1 resonant magnetic perturbation on flow and turbulence towards L-H transition

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Nuclear Fusion 2025年第6期65卷

作者： Zhang, Y. Jiang, M. Guo, Z.B. Diamond, P.H. Guo, W.X. Xu, J.Q. Zhang, N. Wang, Z. Li, Z.J. Zhou, Y. Liang, A.S. Sun, T.F. Ke, R. Gong, S.B. He, X.X. Chen, W. Zhong, W.L. Southwestern Institute of Physics PO Box 432 Chengdu610041 China State Key Laboratory of Nuclear Physics and Technology Fusion Simulation Center School of Physics Peking University Beijing100871 China University of California San Diego San DiegoCA92093 United States International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electric and Electronic Engineering Huazhong University of Science and Technology Wuhan430074 China

The application of resonant magnetic perturbation (RMP) with toroidal mode number n = 1 on HL-3 tokamak inhibits the L-H transition at specific heating power. Following RMP application, the electron density increases in the outer plasma region (ρ > 0.85, where ρ is the normalized toroidal flux), while the electron/ion temperature decreases. Notably, the equilibrium flow shear in the edge region is substantially reduced. This reduction, combined with enhanced micro-instabilities driven by increased profile gradients, leads to enhanced turbulence levels. Consequently, the diminished flow shear becomes less effective in suppressing turbulence, providing a comprehensive explanation for the inhibited access to H-mode. Through a modified one-dimensional predator-prey model that incorporates the effects of RMP-induced radial magnetic perturbations, we have conducted a quantitative analysis of the turbulence and flow dynamics during the L-H transition process. Our results indicate that as the strength of magnetic perturbation increases, the turbulence intensity increases and edge flow shear decreases, in agreement with experimental observations. Additionally, we found that the L-H transition power threshold increases almost linearly with the square of the radial magnetic perturbation intensity. These results enhance our understanding of RMP-induced changes in edge plasma transport, providing valuable insights for optimizing the operation of future tokamaks and improving the performance of fusion reactors. © 2025 The Author(s). Published by IOP Publishing Ltd on behalf of the IAEA.

关键词： Tokamak devices

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Multispectral radiation thermometry approach based on feasible region constraints-divide and conquer optimization

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Optics Express 2025年第10期33卷 20736-20753页

作者： Huang, Hairui Zhang, Wei Yu, Peifeng Xu, Jiawen Liu, Xin Gao, Shan Wang, Chao Zhang, Zezhan Niu, Yi Jiang, Jing Clean Energy Materials and Engineering Center School of Electronic Science and Engineering State Key Laboratory of Electronic Thin Film and Integrated Devices University of Electronic Science and Technology of China Chengdu 611731 China The State Key Laboratory of Precision Measurement Technology and Instruments Department of Precision Instrument Tsinghua University Beijing 100084 China Key Laboratory of Advanced Marine Communication and Information Technology Ministry of Industry and Information Technology School of Information and Communication Engineering Harbin Engineering University Harbin 150001 China

Multispectral radiation thermometry is a widely used non-contact temperature measurement method, particularly in extreme environments. However, accurately retrieving the true temperature remains challenging due to the unknown emissivity of the object. This paper proposes a collaborative optimization approach (feasible region constraints-divide and conquer optimization), which combines a feasible domain constraints method (PCR-PSO) with a divide and conquer optimization algorithm (multi-BFGS). Simulation results show that the proposed approach reduces the temperature inversion error from 0.59% to 0.19% compared to the traditional BFGS algorithm. Experimental results obtained with stainless steel samples indicate an average error of less than 0.2% and an average processing time of 0.2 seconds, highlighting the potential for real-time temperature measurement in engineering applications. © 2025 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement.

关键词： Emissivity Machine learning Neural networks Numerical simulation Silicon carbide Transmittance

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Transition and tunability of bound states in the continuum in metastructures composed of subwavelength gratings and distributed Bragg reflectors

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Optics Express 2025年第10期33卷 21807-21821页

作者： Yang, Bo Hao, Chenxi Wang, Minglu Yu, Tianci Peng, Chao Zheng, Wanhua Liu, Anjin State Key Laboratory of Optoelectronic Materials and Devices Institute of Semiconductors Chinese Academy of Sciences Beijing 100083 China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing 100049 China School of Electronic Electrical and Communication Engineering University of Chinese Academy of Sciences Beijing 100049 China State Key Laboratory of Photonics and Communications School of Electronics & Frontiers Science Center for Nano-optoelectronics Peking University Beijing 100871 China Key Laboratory of Solid-State Optoelectronics Information Technology Institute of Semiconductors Chinese Academy of Sciences Beijing 100083 China Hangzhou Institute for Advanced Study University of Chinese Academy of Sciences Hangzhou 310024 China

Metastructures that are composed of high-contrast gratings (HCGs) and distributed Bragg reflectors (DBRs) exhibit unique optical properties and have potential applications in surface-emitting lasers and sensors. This paper studies the transition and tunability of bound states in the continuum (BICs) in the HCG-DBR metastructure. At the high-symmetry point, the metastructure has a symmetric mode with radiation loss and an antisymmetric mode (BIC) without radiation loss. The bandgap closure and band flipping occur by modulating the filling factor (FF) of the HCG. The band flipping is essentially related to the transition of the BIC. The topological charge characterizing the far-field polarization of the BIC changes during the band flipping. Furthermore, the HCG-DBR metastructure with a dual-period grating is proposed based on the BICs induced by the Brillouin zone folding. BIC can be tuned by applying different perturbations to the dual-period grating. Both single- and dual-band edge quasi-BICs (QBICs) can be realized. Finally, by employing the dramatic phase change of dual QBICs at the resonant wavelength, giant enhancements of both positive and negative Goos-Hänchen (GH) shifts are achieved. This property can be used to design an ultrasensitive refractive index sensor based on the HCG-DBR metastructure with the Bloch surface wave (BSW) and QBIC-enhanced GH shift. This study is useful for the realization of surface-emitting lasers and high-sensitivity optical sensors based on the HCG-DBR metastructure. © 2025 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement.

关键词： Bragg reflectors Laser applications Laser sensors Subwavelength gratings Surface plasmon polaritons Vertical cavity surface emitting lasers

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Single active-site catalysts constructed with nonpolar-bond linked covalent organic frameworks for oxygen reduction reaction

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Science China Materials 2025年第4期68卷 1138-1144页

作者： Fancheng Meng Xuewen Li Qizheng An Shuai Yang Zixing Zhang Qing Xu Bai Xue Xin Jin Fan Zhang School of Chemistry and Chemical Engineering State Key Laboratory of Meal Matrix CompositesShanghai jiao Tong UniversityShanghai 200240China CAS Key Laboratory of Low-Carbon Conversion Science and Engineering Shanghai Advanced Research Institute(SARI)Chinese Academy of Sciences(CAS)Shanghai 201210China School of Chemical Engineering University of Chinese Academy of SciencesBeijing 100049China National Synchrotron Radiation Laboratory University of Science and Technology of ChinaHefei 230029China

Covalent organic frameworks(COFs)with polar linkages have been employed as metal-free catalysts for the oxygen reduction reaction(ORR).However,it is still a big challenge to precisely design or locate the catalytic sites for such kinds of COFs because their polar linkages always make some catalytic *** addition,the polar linkages are facile to bind with O_(2) and oxygen-contained intermediates in the catalytic process,severely weakening the long-term stability of these *** this work,we demonstrated the single metalfree catalytic sites based on the pyridine-cored COFs with nonpolar linkages(C=C bonds)to catalyze the *** nonpolar linkages excluded their potential roles as catalytic sites and also circumvented the possible decomposition in the process of *** modulating the pyridine N with positive charges,the catalytic performance can be previously improved,because of the enhanced Lewis acidity of the carbon atoms next to the pyridine N,and thus favorable for the electrons transfer to the catalytic *** newly-synthesized charged COF showed high activity of a half-wave potential of 0.74 V with a mass activity of 4.34 A g^(-1),which was 50 mV more positive and 1.63 times higher than those of the neutral *** the nonpolar linkages made the COFs display better long-term stability than other metal-free *** theoretical calculation revealed that the ionization of pyridine promoted the formation of the intermediate OOH*,and thus improved the catalytic *** work gives us a new insight into designing single sites based on COFs.

关键词： covalent organic frameworks charging-tuned nonpolar linkage Lewis acidity oxygen reduction reaction

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A Novel Multiple Modes Resonant Sensor Featuring Blue Sideband Excitation 38

A Novel Multiple Modes Resonant Sensor Featuring Blue Sideba...

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38th IEEE International Conference on Micro Electro Mechanical Systems, MEMS 2025

作者： Xu, Jiao Zheng, Zhuoyue Xi, Jingqian Zhang, Ziqian Liu, Huafeng Zhang, Pan Chen, Jianlin Wang, Chen Kraft, Michael Wang, Yuan Martins, R.P. Mak, Pui-In Huazhong University of Science and Technology Moe Key Laboratory of Fundamental Physical Quantities Measurement Pgmf School of Physics Wuhan430074 China University of Macau Institute of Microelectronics State Key Laboratory of Analog and Mixed-Signal Vlsi 999078 China Peking University National Key Laboratory of Advanced Micro and Nano Manufacture Technology School of Integrated Circuits 100871 China Shanghai University School of Microelectronics 200444 China Ku Leuven Department of Electrical Engineering-MNS Leuven3000 Belgium

ISBN: (纸本)9798331508890

This paper reports a novel MEMS resonant structure functioning as a baseline resonant electrostatic force/temperature sensor, highlighting its substantial potential in sensing applications. The resonator, characterized by a dual-cosine structure, is capable of simultaneous multiple resonant modes actuation within the 300 kHz range, through a sole-source drive approach using the recent emerging Blue Sideband Excitation (BSE) technique. This method enables a distinctive multi-modal response, essential for multi-parameter measurements. The research focuses on the sensor's temperature characteristics, electrostatic perturbation sensitivity, and noise floor. Notably, the study reveals intriguing temperature responses across different modes, where certain modes exhibit a significant frequency rise with increasing temperature, this is counter-intuitive with common MEMS resonator devices, prompting further investigation into the underlying mechanisms. The analysis of electrostatic perturbation sensitivity and noise background further unfolds the resonator's performance under various excitation conditions, laying a foundation for advancing sensor functionality, and providing solid evidence on the viability of the subject. To sum up, this study highlights the resonator's potential as a high-precision sensor, opening new opportunities for MEMS sensor design and multi-parameter measurement applications. © 2025 IEEE.

关键词： Microchannels

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Angle-resolved magneto-chiral anisotropy in a non-centrosymmetric atomic layer superlattice

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Science Bulletin 2025年第9期70卷 1406-1409页

作者： Cheng, Long Bao, Mingrui Zhang, Xue Zhang, Jingxian Yang, Qun Li, Qiang Cao, Hui Qiu, Dawei Li, Hui Cheng, Guanglei Zhou, Hua Zuo, Jian-Min Zhou, Xiaodong Shen, Jian Zhu, Zhifeng Wang, Wenbo Zhai, Xiaofang School of Physical Science and Technology ShanghaiTech University Shanghai201210 China CAS Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences University of Science and Technology of China Hefei230026 China School of Information Science and Technology ShanghaiTech University Shanghai201210 China State Key Laboratory of Surface Physics and Institute for Nanoelectronic Devices and Quantum Computing Fudan University Shanghai200433 China X-ray Science Division Advanced Photon Source Argonne National Laboratory LemontIL60439 United States Institutes of Physical Science and Information Technology Anhui University Hefei230601 China Department of Materials Science and Engineering and Materials Research Laboratory University of Illinois Urbana–Champaign UrbanaIL61801 United States ShanghaiTech Laboratory for Topological Physics ShanghaiTech University Shanghai201210 China

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Shape-dependency activity of Nanostructured α-Mn2O3 in direct synthesis of ethylene urea from CO2

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Journal of Industrial and engineering Chemistry 2025年

作者： Wang, Fei Jin, Yulong Zhang, Yue Liang, Xuan Liu, Na Wei, Xuejiao Ke, Yihu Xu, Jie Xue, Bing Jiangsu Key Laboratory of Advanced Manufacturing for High-end Chemicals Advanced Catalysis and Green Manufacturing Collaborative Innovation Center School of Petrochemical and Engineering Changzhou University Changzhou213164 China School of Chemical Engineering and Materials Changzhou Institute of Technology Changzhou213164 China School of Chemistry and Chemical Engineering Ningxia Key Laboratory of Solar Chemical Conversion Technology Key Laboratory for Chemical Engineering and Technology State Ethnic Affairs Commission North Minzu University Yinchuan750021 China

The direct conversion of CO2 into high-value chemicals presents a sustainable pathway for greenhouse gas mitigation. While morphology-dependent catalytic activity has been widely explored in oxidation reactions, its role in CO2-based urea synthesis remains uncharted. Herein, we systematically investigate the structure–activity relationship of shape-controlled α-Mn2O3 catalysts (nanosheets/NS, nanocubes/NC, nanooctahedrons/NO) for synthesizing ethylene urea (EU) from CO2 and ethylenediamine (EDA). The Mn2O3-NS catalyst achieves record-breaking efficiency (96 % EDA conversion, 95 % EU selectivity in 20 min at 140 °C), surpassing all reported catalysts. Through combined XRD, XPS, CO2/NH3-TPD, and TEM analyses, we establish that the superior performance of Mn2O3-NS originates from its abundant surface oxygen vacancies (22.5 %) and more strong acid-base sites – features critically linked to its nanosheet morphology. This work not only provides fundamental insights into morphology-governed CO2 activation mechanisms but also advances the rational design of manganese-based catalysts for industrial CO2 valorization. © 2025 The Korean Society of Industrial and engineering Chemistry

关键词： Nanosheets

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Unusual twin induced recrystallization and corresponding texture optimization in a cold rolled Mg-Gd-Zr alloy during annealing

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Journal of Magnesium and Alloys 2025年第3期13卷 1099-1115页

作者： Ning Lv Lingyu Zhao Hong Yan Boyu Liu Rongshi Chen Zhiwei Shan Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of Sciences72 Wenhua RoadShenyang 110016China School of Materials Science and Engineering University of Science and Technology of China72 Wenhua RoadShenyang 110016China School of Materials Science and Engineering Shenyang Ligong UniversityShenyang110159China School of Materials Science and Engineering Shandong University of Science and TechnologyQingdaoShandong 266590China Center for Advancing Materials Performance From the Nanoscale(CAMP-Nano)&Hysitron Applied Research Center in China(HARCC) State Key Laboratory for Mechanical Behavior of MaterialsXi’an Jiaotong UniversityXi’an 710049China

Twins play an important role in the texture transition during *** a cold rolled high rare earth content magnesium(Mg)alloys with{10–12}extension twins,{11–21}extension twins,{10–11}compression twins and{10–11}-{10–12}double twins and frequent twin-twin interactions,quasi-in-situ electron backscatter diffraction method was used to observe the twin induced static recrystallization(SRX)and related effect on texture during *** results show that basal component was consumed owing to the SRX occurred in basal oriented{10–12}twins and SRXed grains with several speciﬁc orientations show preferential grain *** widely operated in the{10–12}extension and{11–21}extension twins,but absent in most{10–11}compression and{10–11}-{10–12}double twins,which is different to traditional twin induced *** compression/double twins detwinned while only partial tension twins *** of{11–21}twins and resultant twin-twin interaction facilitate the formation of serrated twin boundaries,which can serve as nucleation *** ofdislocation and related dislocation interaction in high dislocation density areas promote the formation of new grain boundaries and related ***dislocations in basal oriented twins release the strain accumulation in compression/double twins and thus result in the absence of *** twin size difference,storage energy and dislocation-twin interaction commonly functioned to the detwinning during *** near-coincide site lattice boundaries that show high mobility were considered to be the important contributor to the preferential grain growth of SRXed grains.

关键词： Magnesium alloy {11–21}twin Texture Static recrystallization Detwinning

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Solar-driven H₂O₂ production by S-scheme heterojunction photocatalyst

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Chinese Journal of Catalysis 2025年第5期72卷 24-47页

作者： Li, Han Wang, Wang Xu, Kaiqiang Cheng, Bei Xu, Jingsan Cao, Shaowen School of Automotive Materials Hubei University of Automotive Technology Hubei Shiyan 442020 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Hubei Wuhan 430070 China Hubei Technology Innovation Center for Advanced Composites Wuhan University of Technology Hubei Wuhan 430070 China School of Chemical and Environmental Engineering Shanghai Institute of Technology Shanghai 201418 China School of Chemistry and Physics & Centre for Materials Science Queensland University of Technology Brisbane 4001 QLD Australia

Hydrogen peroxide (H2O2), as an essential and green chemical, is extensively used in energy and environmental applications. However, the production of H2O2 primarily relies on the anthraquinone method, which is an ene... 详细信息

Hydrogen peroxide (H₂O₂), as an essential and green chemical, is extensively used in energy and environmental applications. However, the production of H₂O₂ primarily relies on the anthraquinone method, which is an energy-intensive method involving multi-step reactions, producing harmful by-product wastes. Solar-driven H₂O₂ production, an alternative route for H₂O₂ generation, is a green and sustainable technology since it only utilizes water and oxygen as feedstock. However, the rapid recombination of charge carriers as well as insufficient redox capability limit the photocatalytic H₂O₂ production performance. Constructing step-scheme (S-scheme) heterojunction photocatalysts has been regarded as an effective strategy to address these drawbacks because it not only achieves spatially separated charge carriers, but also preserves redox capability of the photocatalytic system. This paper covers the recent advances of S-scheme heterojunction photocatalysts for H₂O₂ production in terms of basic principles, characterization techniques, and preparation strategies. Moreover, the mechanism and advantages of S-scheme heterojunction for photocatalytic H₂O₂ generation are systematically discussed. The recent S-scheme heterojunction designs, including inorganic-organic heterojunction, inorganic-inorganic heterojunction, and organic-organic heterojunction, are summarized. Lastly, the challenges and research directions of S-scheme photocatalysts for H₂O₂ generation are presented. © 2025 Dalian Institute of Chemical Physics, the Chinese Academy of Sciences

关键词： Charge migration mechanism H2O2 photosynthesis Solar conversion Step-scheme heterojunction

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