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First-principles study of the Pr-doped bilayer nickelate La3Ni2O7

Physical Review B 2025年第19期111卷 195118-195118页

作者： Zihao Huo Peng Zhang Haoliang Shi Xiaochun Yan Defang Duan Tian Cui Key Laboratory of Material Simulation Methods and Software of Ministry of Education State Key Laboratory of Superhard Materials College of Physics Jilin University Changchun 130012 China MOE Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter Shaanxi Province Key Laboratory of Advanced Functional Materials and Mesoscopic Physics School of Physics Xi'an Jiaotong University Xi'an 710049 China Institute of High Pressure Physics School of Physical Science and Technology Ningbo University Ningbo 315211 China

Recently, the Pr-doped Ruddlesden-Popper (RP) phase of bilayer nickelate La3Ni2O7 has been reported to exhibit a superconducting transition temperature (Tc) of 82.5 K and a superconducting volume fraction of about 57% at high pressure. However, the effect of Pr doping on La3Ni2O7 remains unclear. Here, we studied the crystal structures and electronic properties of Pr-doped La3Ni2O7 at 0 and 15 GPa based on the first-principles calculations to explore the doping effect of Pr. Our findings indicate that the praseodymium atoms prefer to occupy the outer La-O layers site. We then investigated the evolution of crystal structures in both the ambient pressure phase and the high-pressure phase of La3Ni2O7 as a function of doping concentration, revealing inconsistent trends in their evolution with increasing doping levels. Finally, by fitting the bilayer two-orbital model, we propose that doping Pr may reduce the required pressure for the superconductivity of La3Ni2O7. These results not only can help the further experimental search of RP phase nickelate at lower pressure, but also provide a helpful guide for understanding the effect of chemical pressure in an isovalent-doped RP phase nickelate superconductor.

关键词： Crystal atomic structure

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Infrared image deturbulence restoration using degradation parameter-assisted wide & deep learning

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Infrared Physics & technology 2025年 150卷

作者： Yi Lu Yadong Wang Xingbo Jiang Xiangzhi Bai Image Processing Center Beihang University Beijing 102206 China The State Key Laboratory of Virtual Reality Technology and Systems Beihang University Beijing 100191 China Beijing Advanced Innovation Center for Biomedical Engineering Beihang University Beijing 100083 China Key Laboratory of Spacecraft Design Optimization and Dynamic Simulation Technology Ministry of Education Beihang University Beijing 102206 China

Infrared images captured under turbulent conditions are often degraded by complex geometric distortions and blurring, which substantially compromise image clarity and subsequent analysis. In this paper, we recast the infrared deturbulence problem as a more general image restoration task and propose a parameter assisted image restoration method that leverages degradation prior information from the turbulent infrared images. Specifically, we propose an ingenious and efficient multi-frame image restoration network (DparNet) with wide & deep architecture, which integrates degraded images and prior knowledge of degradation to reconstruct images with ideal clarity and stability. The degradation prior is directly learned from degraded images in form of key degradation parameter matrix, with no requirement of any off-site knowledge. The wide & deep architecture in DparNet enables the learned parameters to directly modulate the final restoring results, boosting spatial & intensity adaptive image restoration. We demonstrate the proposed method on infrared image deturbulence by constructing a dedicated dataset of 49,744 images to rigorously evaluate its performance under challenging turbulence degradation. To further validate the generality of our approach, a supplementary visible image denoising experiment was also conducted on a larger dataset containing 109,536 images. The experimental results show that our DparNet significantly outperform SoTA methods in restoration performance and network efficiency. More importantly, by utilizing the learned degradation parameters via wide & deep learning, we can improve the PSNR of image restoration by 0.6 ∼ 1.1 dB with less than 2% increasing in model parameter numbers and computational complexity. Our work suggests that degraded images may hide key information of the degradation process, which can be utilized to boost spatial & intensity adaptive image restoration.

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Formation Mechanisms and Atmospheric Implications of Summertime Nitrous Acid (HONO) During Clean, Ozone Pollution and Double High Pollution Periods in Beijing

SSRN

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SSRN 2022年

作者： Xuan, Huiying Zhao, Yaqi Ma, Qingxin Chen, Tianzeng Liu, Jun Wang, Yonghong Liu, Chang Wang, Yafei Liu, Yongchun Mu, Yujing He, Hong State Key Joint Laboratory of Environment Simulation and Pollution Control Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing100085 China College of Resources and Environment University of Chinese Academy of Sciences Beijing100049 China Center for Excellence in Regional Atmospheric Environment Institute of Urban Environment Chinese Academy of Sciences Xiamen361021 China State Key Laboratory of Severe Weather Key Laboratory of Atmospheric Chemistry of China Meteorological Administration Chinese Academy of Meteorological Sciences Beijing100081 China Beijing Institute of Petrochemical Technology Beijing102617 China Aerosol and Haze Laboratory Beijing Advanced Innovation Center for Soft Matter Science and Engineering Beijing University of Chemical Technology Beijing100029 China

Nitrous acid (HONO) is a key precursor of the hydroxyl radicals (OH) and has a significant impact on air quality. Nowadays, the source of HONO is still controversial due to its complex formation mechanisms, which is widely explored in extensive field and laboratory studies. In this study, the pollution characteristics and source contribution of HONO under different air quality conditions in summer in Beijing were analyzed. The observation periods were classified as three typical periods: clean, ozone pollution, and double high pollution (co-occurrence of high PM2.5 and O3 concentrations). The average concentrations of observed HONO were 0.38 ± 0.35 ppb, 0.21 ± 0.18 ppb, 0.26 ± 0.20 ppb and 0.54 ± 0.45 ppb during the whole, clean, ozone and double high periods, respectively. The elevated HONO levels at night were attributed to vehicle emissions and the RH-dependent heterogeneous conversion of NO2 to HONO. The average emission ratio (HONO/NOx) was 0.85 ± 0.38%, and the mean value of calculated nocturnal NO2 to HONO conversion frequency was 0.0076 ± 0.0031 h-1. Based on daytime HONO budget analysis, the largest potential source of HONO was the homogeneous reaction of NO and OH (0.33 and 0.34 ppb h-1), followed by the unknown source (0.11 and 0.21 ppb h-1) during clean and ozone periods, while the unknown source (0.49 ppb h-1) played the predominant role during double high period. The unknown sources of HONO could be attributed to the photo-enhanced heterogeneous conversion of NO2 and the photolysis of particulate nitrate. Furthermore, the photolysis of ozone (0.17, 0.34 and 0.44 ppb h-1) was the major contributor to primary OH during three typical periods. HONO photolysis contributed considerable amounts of primary OH (0.32 ppb h-1) during double high period. These results are helpful to further understand the linkage between HONO and air quality variation. © 2022, The Authors. All rights reserved.

关键词： Ozone

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Fatigue Behavior of Thermal Barrier Coated DD6 Single Crystal Superalloy at 900 °C

Fatigue Behavior of Thermal Barrier Coated DD6 Single Crysta...

引用

Chinese Materials Conference, CMC 2018

作者： Dong, Jianmin Li, Jiarong Mu, Rende Tian, He Science and Technology on Advanced High Temperature Structural Materials Laboratory Beijing Institute of Aeronautical Materials Beijing100095 China Aviation Key Laboratory of Science and Technology on Advanced Corrosion and Protection for Aviation Material Beijing Institute of Aeronautical Materials Beijing100095 China

ISBN: (纸本)9789811359439

Thermal barrier coatings (TBCs) were deposited on DD6 specimens with [001] orientation, and the TBCs coated DD6 specimens were exposed at 1150 °C for one hour. Then, both the TBCs coated and bared specimens were subjected to high-cycle fatigue (HCF) testing at 900 °C in ambient atmosphere. The results revealed that the HCF life decreased with increasing stress amplitude and the fatigue strength of the TBCs coated substrate was higher than that of the bared alloy. There are two main reasons for this phenomenon, one is because the coating can bear part of the load and make the specimens stronger and the other is the existence of residual compressive stresses. SEM and TEM were used to observe the microstructure near the fracture. For the TBCs coated alloy, many pores and cracks appeared at the bond coat after HCF test, and the fatigue cracks may be resulted from some of them. In the process of testing, the crack expanded to the substrate and propagated along {111} octahedral slip planes. © 2019, Springer Nature Singapore Pte Ltd.

关键词： Thermal barrier coatings

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Multi-layer alternating structured alginate hydrogels featuring exceptional flexibility and electromagnetic shielding performance

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Journal of Colloid and Interface Science 2025年第PT 1期699卷 138103页

作者： Taian He Chuyang Liu Zhiwei Chen Chuanhui Nie Wangpeng Ren Yujing Zhang Hang Zhang Guangbin Ji School of Material Science and Technology Nanjing University of Aeronautics and Astronautics Nanjing 210016 PR China School of Materials Science and Engineering Nanjing University of Science and Technology Nanjing 210094 PR China Aviation Key Laboratory of Science and Technology on Advanced Surface Engineering AVIC Manufacturing Technology Institute Beijing 100024 PR China

The booming development of flexible electronic devices requires innovate electromagnetic shielding materials integrated with both superior flexibility and absorption capacities. Hydrogels incorporated with conductive fillers emerge as formidable contenders while suffer inadequate electromagnetic shielding performance and significant secondary pollution. In this work, the efficient synergy of CNTs and Co nanoparticles bestowed the hydrogel with both favorable dielectric and magnetic loss for efficient electromagnetic shielding performance. Concurrently, the Co-CNT hydrogel film exhibits a certain mechanical property owing to the hydrogen bonds between CNT/Co-CNT particles and SA hydrogel. Furthermore, the design of multi-layer structure, intricately interspersed with fillers of Co-CNT and CNT in an alternating pattern, features an “absorption-reflection-reabsorption” mechanism to reinforce the dissipation of electromagnetic waves within the hydrogels. Ultimately, the CNT/Co-CNT multi-layer hydrogel achieves an outstanding mechanical flexibility and considerable electromagnetic shielding performance of 41 dB at 0.7 mm, while the SE A /SE T value is greater than 85 %, which is conspicuously superior to the majority of electromagnetic shielding conductive hydrogel materials. This work offers a novel idea for the development of intelligent flexible EMI shielding materials and holds latent application prospects in the fields of wearable smart devices and military applications.

关键词： CNT Electromagnetic interference shielding Hydrogel Multi-layer construction

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Origin of versatile polarization state in CuInP2S6

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Physical Review B 2023年第16期108卷 L161406-L161406页

作者： Xuanlin Zhang Chengcheng Xiao Zeying Zhang Luqi Dong Hui Pan Chao Cao Shengyuan A. Yang Su-huai Wei Yunhao Lu State Key Laboratory of Silicon and Advanced Semiconductor Materials School of Materials Science and Engineering Zhejiang University Hangzhou 310027 China School of Physics Zhejiang University Hangzhou 310027 China Departments of Materials and Physics and the Thomas Young Centre for Theory and Simulation of Materials Imperial College London London SW7 2AZ United Kingdom College of Mathematics and Physics Beijing University of Chemical Technology Beijing 100029 China Institute of Applied Physics and Materials Engineering University of Macau Macao S. A. R. China Beijing Computational Science Research Center Beijing 100193 China

Exotic electric polarization-related phenomena have recently been reported in layered van der Waals material such as CuInP2S6 and its derivatives, but the physical origin for such behaviors, especially the formation of quadrupole-well ferroelectric states and the anomalous polarization switching between these states, has not been clearly understood. Here, we provide a simple theoretical explanation using group theory analysis, highlighting the role of local symmetry-determined orbital interactions between copper ions and surrounding ligands. Based on this theory, we predict a surprising effect: carrier doping, which is commonly believed to suppress electric polarization, can lead to enhanced polarization in CuInP2S6. Our first-principles simulations confirm this unusual effect and further show that an elevated hole doping level can cause electric polarization to give way to emerging ferromagnetism. Our results not only pave a way to realize ferroelectric metals, but also broaden the scope of magnetoelectric coupling mechanisms and may help enrich the potential applications of layered ferroelectric materials in the future.

关键词： Electric polarization Van der Waals systems Quantum group symmetries Density functional theory

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Optimization of low-energy slow extraction efficiency of XiPAF

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Journal of Physics: Conference Series 2024年第5期2687卷 052033-052033页

作者： Z J Wang H J Yao Y Yang X Y Liu Y Li Y Xiong S X Zheng X W Wang Key Laboratory of Particle and Radiation Imaging (Tsinghua University) Ministry of Education Beijing 100084 China Laboratory for Advanced Radiation Sources and Application Tsinghua University Beijing 100084 China Department of Engineering Physics Tsinghua University Beijing 100084 China State Key Laboratory of Intense Pulsed Radiation Simulation and Effect (Northwest Institute of Nuclear Technology) Xi’an 710024 China

Xi'an Proton Application Facility (XiPAF) synchrotron provides 10∼200MeV proton beam for the experimental simulation of the space radiation environment. Due to the space charge effect, the slow extraction of 10 MeV proton beam is a work full of challenges. In a past experiment, the total extraction efficiency was over 65% with 4.5 ∽ 6.5×10¹⁰ protons stored before extraction but decreased to 52% with 9×10¹⁰ protons stored. In order to study the beam loss caused by a strong space charge effect, based on experimental parameters, the beam loss fractions at different positions of XiPAF synchrotron are obtained through the simulation. According to the beam loss analysis, optimized parameters are found for reference in subsequent experiments. It is also noted that negative beam average momentum spread before extraction is beneficial to the improvement of extraction efficiency.

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Differential equation model of the tune ripple effect on beam spill ripple in RFKO slow extraction

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Journal of Physics: Conference Series 2024年第5期2687卷 052035-052035页

作者： Z J Wang H J Yao W B Ye X Y Liu Y Li Y Xiong S X Zheng X W Wang Key Laboratory of Particle and Radiation Imaging (Tsinghua University) Ministry of Education Beijing 100084 China Laboratory for Advanced Radiation Sources and Application Tsinghua University Beijing 100084 China Department of Engineering Physics Tsinghua University Beijing 100084 China State Key Laboratory of Intense Pulsed Radiation Simulation and Effect (Northwest Institute of Nuclear Technology) Xi’an 710024 China

Beam uniformity is an important factor that must be considered in slow extraction optimization, and the tune ripple caused by the power supply ripple is an important factor that causes beam uniformity to deteriorate. In this study, based on the beam excitation concept for two regions (extraction and diffusion regions), a differential equation of beam spill under the influence of a mono frequency tune ripple was established. By solving and analysing the differential equation, several conclusions were obtained and verified by simulation.

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An atomic insight into role of temperature and stress on acidic corrosion behaviour and mechanical property of polycrystalline Fe-based alloys

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Surfaces and Interfaces 2025年 70卷

作者： Wang, Zouxueyin Li, Jia Xing, Shaohua Liu, Bin Zhang, Yong Fang, Qihong State Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle College of Mechanical and Vehicle Engineering Hunan University Changsha 410082 China National Key Laboratory for Marine Corrosion and Protection Luoyang Ship Material Research Institute Qingdao 266237 China State Key Laboratory of Powder Metallurgy Central South University Changsha 410083 China Naval Aviation University Qingdao Campus Qingdao 266041 China

Fe-based alloys have great potential for applications in the aerospace and nuclear industries due to suitable strength and ductility, and high corrosion resistance. However, the acidic corrosion behaviour of polycrystalline Fe-based alloys has not been resolved at atomic scale. In this work, we investigate the acidic corrosion behaviour and mechanical property in nanocrystalline Fe-based alloys, with a focus on the influence of temperature and stress using reactive molecular dynamics (MD) simulations. Deep-sea corrosion experiments are conducted on low-alloy steel to investigate the effect of stress on the corrosion behavior. The results show that the corrosion process exhibits distinct stages and ultimately reaches a state of dynamic equilibrium involving the destruction and regeneration of a passivation film. The corrosion rate at grain boundaries is higher than that within the grains. Additionally, an increase in temperature promotes the rate of metal dissolution, diffusion, and corrosion reactions. The high stress exacerbates corrosion and leads to the formation of more complex corrosion products. The large deformation inhibits the worsening of corrosion. More importantly, corrosion has a significant impact on the yield strength and elastic modulus of Fe-based alloys, reducing their mechanical properties, especially at the elevated temperatures. Deep-sea corrosion experiments reveal the increasing pressure reduces both corrosion rate and pitting depth, while promoting more numerous but shallower pits at higher stresses. The corrosion products align with simulation results, though structural disorder weakens protective capacity. This work affords an atomic insight into the acidic corrosion behaviour and its mechanism origin, which can deepen the fundamental understanding in corrosion processes at the atomic level. © 2025 Elsevier B.V.

关键词： Corrosion Damage mechanism Fe-based alloys Reactive molecular dynamic simulation

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Ternary quasifission in collisions of actinide nuclei

arXiv

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arXiv 2023年

作者： Zhang, D.D. Li, B. Vretenar, D. Nikšić, T. Ren, Z.X. Zhao, P.W. Meng, J. State Key Laboratory of Nuclear Physics and Technology School of Physics Peking University Beijing100871 China Physics Department Faculty of Science University of Zagreb Zagreb10000 Croatia Institut für Kernphysik Institute for Advanced Simulation Jülich Center for Hadron Physics Forschungszentrum Jülich JülichD-52425 Germany Helmholtz-Institut für Strahlen- und Kernphysik Bethe Center for Theoretical Physics Universität Bonn BonnD-53115 Germany

The microscopic framework of time-dependent covariant density functional theory is applied to a systematic study of ternary quasifission in collisions of pairs of 238U nuclei. It is shown that the inclusion of octupole degree of freedom in the case of head-to-head collisions, extends the energy window in which ternary quasifission occurs, and greatly enhances the number of nucleons contained in a middle fragment. Dynamical pairing correlations, included here in the time-dependent BCS approximation, prevent the occurrence of ternary quasifission in head-to-head collisions, and have an effect on the location of the energy window in which a middle fragment is formed in tail-to-tail collisions. In the latter case, as well as for tail-to-side collisions, the formation of very heavy neutron-rich systems in certain energy intervals is predicted. Copyright © 2023, The Authors. All rights reserved.

关键词： Density functional theory

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