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A comprehensive assessment of anthropogenic impacts, contamination, and ecological risks of toxic elements in sediments of urban rivers: A case study in Qingdao, East China

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Environmental Advances 2022年 7卷

作者： Gu, Xiang Lin, Chunye Wang, Baodong Wang, Jing Ouyang, Wei State Key Laboratory of Water Environment Simulation School of Environment Beijing Normal University Beijing 100875 China MNR Key Laboratory of Marine Eco-Environmental Science and Technology First Institute of Oceanography Ministry of Natural Resources Qingdao 266061 China College of Water Science Beijing Normal University Beijing 100875 China Advanced Interdisciplinary Institute of Environment and Ecology Beijing Normal University Zhuhai 519087 China

Urban river sediments usually serve as a sink for potentially toxic elements (PTEs) during the process of urbanization. A systematic evaluation of human influence, contamination, and risk assessment of PTEs in urban river sediments is essential for sustaining river health. In this study, 24 sediment samples were collected from 5 rivers in Qingdao, a coastal urbanized city in East China. Zinc had the highest concentration (141 ± 134 mg/kg), followed by Cr, Cu, Pb, Ni, Co, As, and Cd. Generally, the PTE concentrations were higher in eastern rivers than those in western rivers affected by intensive industrialization and urbanization. The principal component analysis identified three principal components: natural origins (As, Co, Cr, and Ni), urban activities (Cd, Cu, Pb, and Zn), and atmospheric deposition (Pb), respectively. The excessive concentrations of Cd and Pb were frequently appeared in the sampling sites, with the anthropogenic contribution rates of 8.4%–77% and 6.6%–87%, respectively. Additionally, the river sediments experienced moderate contamination of As, Cd, Cu, Pb, and Zn. Among the PTEs, Cd had moderate ecological risk and others had low risk. The results of Monte Carlo simulation were generally in accordance with the detected contamination and risk levels, except for several elements (Cu and Zn) with huge spatial heterogeneity. According to the Monte Carlo simulation, the river sediments could undergo extremely high contamination and high ecological risk of the PTEs in the worst situation. Thus, it becomes essential that PTEs in the urban rivers should not be overlooked before their discharge into the sea. © 2021 The Author(s)

关键词： Excessive concentration Monte Carlo simulation Risk assessment Toxic elements Urban river

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Research on a high-current CW proton hybrid accelerating cavity incorporating coupled four-vane RFQ and CH DTL structures

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Journal of Instrumentation 2025年第5期20卷 P05047-P05047页

作者： Tuo, Mingze Wang, Baichuan Liu, Wolong Zhuo, Xin Yang, Fuyu Wang, Minwen Yan, Yihua Zhang, Xiaodong Wang, Zhongming Xing, Qingzi Key Laboratory of Particle and Radiation Imaging Tsinghua University Ministry of Education Beijing100084 China National Key Laboratory of Intense Pulsed Radiation Simulation and Effect Northwest Institute of Nuclear Technology Xi'an710024 China Laboratory for Advanced Radiation Sources and Application Tsinghua University Beijing100084 China Department of Engineering Physics Tsinghua University Beijing100084 China

To enhance the accelerating efficiency of the high-current accelerator for a neutron source, a 100-mA, 162.5-MHz, CW compact hybrid accelerating cavity incorporating inductively coupled four-vane RFQ and CH DTL structures is designed in this paper. The dynamics design, the RF structure design, error analysis, and water-cooling design of the hybrid cavity have been accomplished. The proton beam is accelerated from 80 keV to 0.8 MeV via the RFQ and is further accelerated to 3 MeV by the DTL. The coupling modes of the two-resonant-cavity are analyzed. The designed length of the hybrid accelerating cavity is 3.94 m, and its total power consumption is 101.3 kW. © 2025 IOP Publishing Ltd and Sissa Medialab. All rights, including for text and data mining, AI training, and similar technologies, are reserved.

关键词： Accelerator Applications Accelerator modelling and simulations (multi-particle dynamics, single-particle dynamics) Beam dynamics

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Multi-dimensional simulations for extensive off-design conditions of gas turbines by iterative-coupled methods using different characteristic maps of coaxial compressor and turbine

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Case Studies in Thermal Engineering 2025年 72卷

作者： Weimin Deng Guangming Ren Linyuan Jia Zuojun Wei Yuchun Chen Xiaohua Gan School of Power and Energy Northwestern Polytechnical University Xi'an 710072 China Department of Mechanics and Aerospace Engineering Southern University of Science and Technology Shenzhen 518055 China Science and Technology on Altitude Simulation Laboratory Mianyang 621000 China Shenzhen Key Laboratory of Wide-Speed-Range and Variable-Density Continuous Wind Tunnel Southern University of Science and Technology Shenzhen 518000 China National Key Laboratory of Science and Technology on Advanced Light-duty Gas-turbine Xi'an 710129 China

Multi-dimensional simulations offer a complementary numerical platform to gas turbine experimentation, generating supportive data for training adaptation and artificial intelligence models. However, the application of iterative-coupled simulations to extensive off-design conditions depends significantly on the accuracy of generic characteristic maps, particularly near choke and stall regions. In this study, multi-dimensional simulation based on iterative-coupled models using three different sets of maps was developed. Based on experimental speed characteristics data, the standard deviation of performance parameters simulated from the three iterative-coupled models was found to be less than 10 −3 . Further analysis reveals the convergence consistent traits that the different characteristic maps used in the iterative-coupled simulations only affect convergence speed and scope and do not impact the final convergence results. To apply iterative-coupled simulations to extensive off-design conditions, a self-moving strategy based on the convergence consistent traits of different characteristic maps was developed. The iterative-coupled simulations using the self-moving strategy have an extensive convergence scope, including adjustable-nozzle-area conditions (0.0013–0.008 m 2 , 78 %–479 %) and adjustable-power-extraction conditions (0–16 kW, 0 %–80 %). This demonstrates that the self-moving strategy for inexact generic characteristic maps can apply iterative-coupled simulations to extensive off-design, compared to the CLM with exact specific characteristic maps.

关键词： Iterative-coupled simulations Component-level model Adaptation method Gas turbine Thermodynamics Computational fluid dynamics

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A post-treatment to reduce stress concentration sensitivity under intermediate-temperature fatigue in GH4169: High-energy impact composite modification

Transactions of Materials Research

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Transactions of Materials Research 2025年第3期1卷

作者： Guoxin Lu Qiang Wang Bonnie Attard Arif Rochman Guofang Zhang Luqing Cui Zhong Ji Glenn Cassar MOE Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials Shandong University Jinan 250061 China Aviation Key Laboratory of Science and Technology on Advanced Corrosion and Protection for Aviation Material AECC Beijing Institute of Aeronautical Materials Beijing 100095 China Department of Metallurgy and Materials Engineering University of Malta MSD 2080 Malta Institute of Engineering and Transport The Malta College of Arts Science & Technology PLA 9032 Malta National Key Lab of Aerospace Power System and Plasma Technology Xi’an Jiaotong University Xi’an 710049 China

The study focuses on a novel post-treatment method, high-energy impact composite modification, combining mechanical shot peening and laser shock processing to improve the fatigue performance of the nickel-based superalloy GH4169 at intermediate temperatures. The synergistic interaction between mechanical impact (SP-induced plastic deformation) and laser-induced shock waves enabled a 2.5-fold increase in effective treatment depth (up to 1500 μm) compared to SP alone (400 μm), while achieving a surface hardness of 520 HV and compressive residual stress of −1465 MPa, exceeding single-process results by 4.5% and 54.2%, respectively. The dual-impact approach significantly enhanced surface hardness and compressive residual stress, addressing the high sensitivity to stress concentration. Experimental results demonstrate that HEICM eliminated stress concentration sensitivity at 650 °C, elevating the fatigue limit of notched specimens (Kt = 3) to 638 MPa – equivalent to the fatigue strength of smooth specimens (Kt = 1) in conventional grinding states (636 MPa). This represents a 116% improvement over untreated notched specimens (295 MPa) and surpasses SP-treated counterparts (446 MPa) by 43%, thereby extending the fatigue life of GH4169 alloys in aerospace applications.

关键词： Composite modification Shot peening Surface strengthening Superalloy High-cycle fatigue

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

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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...

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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 699卷

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.

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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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