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Controllable preparation and microwave absorption properties of shape anisotropic Fe_(3)O_(4) nanobelts

Journal of Materiomics 2021年第5期7卷 957-966页

作者： Jialiang Pan Rujing Zhang Jun Ling Min Wang Zechen Li Zhen Zhen Limin He Hongwei Zhu State Key Lab of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing100084China The First Scientific Research Institute of Wuxi Wuxi214035JiangsuChina Key Laboratory of Science and Technology on Advanced Corrosion and Protection for Aviation Material AECC Beijing Institute of Aeronautical MaterialsBeijing100095China

To substantially prevent electromagnetic threatens,microwave absorbing materials(MAMs)are required to eliminate surplus electromagnetic *** a typical MAM,Fe_(3)O_(4) particles with complex permittivity and permeability have been widely applied due to the coexistence of magnetic loss and dielectric ***,the necessary high mass fraction significantly limited its applications,thus Fe_(3)O_(4) nanostructures have been extensively investigated to overcome this *** this work,uniform Fe_(3)O_(4) nanobelts were prepared by electrospinning and two-step thermal *** controlling the composition and viscosity of the electrospinning precursor solution,Fe_(3)O_(4) nanobelts with tunable lateral sizes(200 nme1 mm)were *** samples with low content(only 16.7 wt%)Fe_(3)O_(4) exhibited wide maximum effective absorbing bandwidths(EAB)over 3 GHz,and Fe_(3)O_(4) nanobelts with smaller lateral sizes showed a maximum EAB of 4.93 ***,Fe_(3)O_(4) nanobelts with smaller lateral sizes presented superior reflection loss properties,the lowest reflection loss reached-53.93 dB at 10.10 GHz,while the maximum EAB was up to 2.98 *** excellent microwave reflection loss of Fe_(3)O_(4) nanobelts was contributed to the enhanced synergistic effect of magnetic loss,dielectric loss,and impedance matching,originated from the hierarchically cross-linked networks and shape *** study could broaden the practical applications of magnetic absorbers,and provided an approach for the development of shape anisotropic magnetic materials.

关键词： Fe_(3)O_(4) Nanobelts Shape anisotropy Microwave absorption Reflection loss

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Multi-interface modification induced crack deflection behavior and enhanced fracture resistance in thermal barrier coatings

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Journal of Alloys and Compounds 2025年 1031卷

作者： Li, Qicheng Cui, Xiufang Jing, Yongzhi Xu, Wei Wang, Yi Chen, Zhuo Zhang, Zhijia Fang, Yongchao Shang, Tong Jin, Guo Institute of Surface/Interface Science and Technology Key Laboratory of Superlight Material and Surface Technology of Ministry of Education College of Material Science and Chemical Engineering Harbin Engineering University Harbin150001 China Northwest Institute for Nonferrous Metal Research Xi an710016 China The Military Industry Program Evaluation Center of Costind of SASTIND Beijing100048 China No.703 Research Institute China State Shipbuilding Co. Ltd Harbin150078 China Aviation Key Laboratory of Science and Technology on Advanced Corrosion and Protection for Aviation Material Beijing Beijing Institute of Aeronautical Materials Beijing100095 China

Conventional thermal barrier coatings (TBCs) composed of yttria-stabilized zirconia (YSZ) ceramic top layers and MCrAlY (M = Ni, Co, or their combination) alloy bond coats are prone to brittle fracture and interfacial delamination under extreme thermo-mechanical-chemical coupled *** study develops a composite-toughened thermal barrier coating (TBC) system integrating three innovations: laser-modified SiC whisker-reinforced YSZ-WL ceramic layers, a novel NiCoCrFeAl0.8Si0.1(NbMoTaW)0.1 high-entropy alloy bond coat, and hoop-patterned laser-textured interfaces. Compared to conventional TBC1 (NiCoCrAlY/YSZ), the optimized TBC3 demonstrates 64.3 % higher interfacial strength, survives 150 thermal shock cycles at 1100°C (20 % spallation area), and shows 61.43 % lower erosion mass loss post-thermal cycling. The YSZ-WL layer reduces cyclic molten salt corrosion mass loss by 22.58 % versus *** advancements highlight the synergistic effects of whisker toughening (crack deflection/bridging), high-entropy alloy bond coats (suppressed TGO growth), and hoop-textured interfaces (guided crack propagation), establishing a groundbreaking strategy for extreme-environment TBC applications. © 2025 Elsevier B.V.

关键词： Brittle fracture

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Research on the Pressure Comfort of Pilot Helmets 32

Research on the Pressure Comfort of Pilot Helmets

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32nd Congress of the International Council of the Aeronautical sciences, ICAS 2021

作者： Wang, Xiujuan Xu, Jing Wang, Juhao Mi, Jiachen Jiang, Yaming Aerospace Life-support Industries LTD Xiangyang441003 China Aviation Key Laboratory of Science and Technology on Life-support Technology Xiangyang441003 China Tiangong University School of Textile Science and Engineering Tianjin 300387 China Intel Engineering Simulation Technology Co. Ltd. Dalian116023 China

ISBN: (纸本)9783932182914

With the advancement of technology, the functions of pilot helmets are constantly being upgraded. The highly integrated helmets with display, positioning, sensing, night vision and camera are the future development trends. Although the multifunctional and highly integrated design enhances the combat maneuverability, the add-on components will result in local tenderness as the weight gain and center of gravity change, which seriously affects the pilot's wearing comfort, especially in high-speed overload conditions. These factors have become potential factors affecting flight safety. At present, experience-based methods are no longer suitable for new product development. Therefore, it is urgent to establish a simulation model on the pressure comfort of "helmet-head", the finite element method is used for simulation calculation. This paper studies different conditions of the center of gravity, and using the standard head shape, ball shape and real head shape as a control, to analyze the center of gravity, the difference of the head shape, and the influence of overload loading on the pressure distribution. By comparing with the actual flight situation, the simulation results are consistent with the actual situation, which proves that the simulation model has good credibility. © 2021 32nd Congress of the International Council of the Aeronautical sciences, ICAS 2021. All rights reserved.

关键词： Flight simulators

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Effect of Dislocation Characteristics on Diamond Radiation Detector Performance by Affecting Dark Current

SSRN

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SSRN 2024年

作者： Mu, Lianxi Yuan, Xiaolu Feng, Zhelin Liu, Linyue Liu, Jinlong Chen, Liangxian Wei, Junjun Ouyang, Xiaoping Li, Chengming Institute for Advanced Materials and Technology University of Science and Technology Beijing Beijing100083 China School of Mechanical Engineering University of Science and Technology Beijing Beijing100083 China School of Energy and Power Engineering Xi'an Jiaotong University Xi’an710049 China State Key Laboratory of Intense Pulsed Radiation Simulation and Effect Northwest Institute of Nuclear Technology Xi’an710024 China School of Materials Science and Engineering Xiangtan University Xiangtan411105 China

The application of diamond radiation detectors in high-energy physics requires effective control of impurity content in the material. Microwave plasma chemical vapor deposition (MPCVD) technology has made significant progress in the synthesis of high-purity single crystal diamonds. However, when the impurity content is controlled to the ppb level, there are still significant differences in the performance of diamond radiation detectors. In this study, we prepared high-purity single-crystal CVD diamonds using self-made MPCVD equipment. Electron paramagnetic resonance (EPR) testing showed that the content of substituted nitrogen (Ns) impurities in diamonds were 0.77 and 1.04 ppb, respectively. The dislocation densities measured by X-ray rocking curves were 3.3 × 106 cm-2 and 4.7 × 106 cm-2, respectively. After metallization, the charge collection efficiency (CCE) of diamond radiation detectors were 12.61% and 98.27%, respectively. There are significant differences in CCE between diamond detectors. By studying the influence of dislocations and stress distribution in diamonds on dark current, it is believed that after controlling the content of Ns impurities in diamond, the effect of dislocations along the [110] direction on detector performance is greater than that in the [100] direction for diamonds with similar dislocation densities. This may be due to the easy decomposition of dislocations in the [110] direction, leading to unstable diamond growth process and resulting the non-homogeneous epitaxy. © 2024, The Authors. All rights reserved.

关键词： Dark currents

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Direct Evidence of the Relationship between Piezoelectricity and Catalytic Activity

SSRN

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SSRN 2025年

作者： Gao, Wenpeng Zheng, Huashan Luo, Huajie Zhang, Haibo Jo, Wook Xie, Bing School of Power and Energy Jiangxi Key Laboratory of Green General Aviation Power Nanchang Hangkong University Nanchang330063 China Functional Materials and Acousto-optic Instruments Institute School of Instrumentation Science and Engineering Harbin Institute of Technology Harbin150080 China School of Materials Science and Engineering University of Science and Technology Beijing Beijing100083 China School of Materials Science and Engineering Huazhong University of Science and Technology Wuhan430074 China Ulsan44919 Korea Republic of Beijing Advanced Innovation Center for Materials Genome Engineering China State Key Laboratory of Material Processing and Die & Mould Technology China School of Materials Science and Engineering

Piezocatalysis is highly valued for its efficient energy conversion and environmental capabilities. However, the fundamental connection between piezoelectricity and piezocatalytic activity remains to be thoroughly investigated. Herein, piezoceramic thin flakes with varying levels of piezoelectricity were examined to quantitatively assess the impact of the piezoelectric coefficient (d33) on the piezocatalytic activation in energy and environment applications. The piezoceramic flake, 220 μm thick, possessing the highest piezoelectricity (d33 = 1100 pC/N), demonstrated the highest H2O2 yield (572 μM h-1) and the fastest degradation rate (k = 0.0725 min-1) of Rhodamine B (RhB), exceeding the best performance of previously reported ceramic blocks. In contrast, the same thickness flake with the lowest piezoelectricity (d33 = 150 pC/N) exhibited the weakest piezocatalytic performance. By analyzing internal carrier characteristics and simulating carrier migration pathways under an electric field, a quantitative relationship between piezoelectricity and piezocatalytic activity was established. The piezoceramic flake with higher piezoelectricity demonstrated a higher effective free carrier concentration, a larger number of transiently migrating carriers, and a shorter migration distance due to a stronger built-in electric field, resulting in enhanced piezocatalytic activity. This work clearly elucidates the relationship between piezoelectricity and piezocatalytic activity. © 2025, The Authors. All rights reserved.

关键词： Piezoelectricity

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Erratum to:Finite element simulation and experimental test of the wear behavior for self-lubricating spherical plain bearings

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Friction 2024年第7期12卷 1620-1620页

作者： Yahong XUE Jigang CHEN Sumin GUO Qingliang MENG Junting LUO School of Mechanical Engineering Yanshan UniversityQinhuangdao 066004China Aviation Key Laboratory of Science and Technology on Generic Technology of Self-Lubricating Spherical Plain Bearing Yanshan UniversityQinhuangdao 066004China Education Ministry Key Laboratory of Advanced Forging and Stamping Technology and Science Yanshan UniversityQinhuangdao 066004China

Erratum to Friction 10(6):803–841(2022)Yahong Xue,Jigang Chen,Sumin Guo,Qingliang Meng&Junting *** element simulation and experimental test of the wear behavior for self-lubricating spherical plain *** 6(3):297–306(2018).https://***/10.1007/s40544-018-0206-x The authors regret that there was an inadvertent error in Fig.10(c)after checking the *** is important to note that the change does not impact the main conclusion of the *** 10(c)on page 304 was selected as the incorrect picture,and the accurate version of Fig.10(c)is provided as below.

关键词： wear Friction bearings

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A Staged Strategy for MMC Offshore Converter Station Under Asymmetric AC Fault

A Staged Strategy for MMC Offshore Converter Station Under A...

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IEEE Conference on Energy Internet and Energy System Integration (EI2)

作者： Fangyuan Li Longze Kou Jiapei Zhou Jie Hao State Key Laboratory of Advanced Power Transmission Technology Beijing Key Laboratory of DC Grid Technology & Simulation State Grid Smart Grid Research Institute CO. LTD. Beijing China State Grid Shanxi Electric Power Company electric power Science Research Institute Shanxi China

At present, offshore wind power has become an important development direction for wind power generation. Offshore wind farms often use high-voltage direct current transmission technology with modular multi-level voltage source converters (MMC-HVDC) to transmit electricity to the grid. However, the fault response characteristics of offshore wind farms through the MMC-HVDC transmission system are different from those through AC transmission way. Therefore, it is significant that studying the fault ride through (FRT) technology of offshore wind farms through the MMC-HVDC grid connection system for practical engineering. An electromagnetic transient simulation model for an offshore wind farm composed of a direct drive permanent magnet synchronous generator (D-PMSG) connected to the grid is established through MMC-HVDC transmission technology. The mechanism and suppression strategy of overvoltage generation in the transmission network are provided during the fault clearance and recovery phase of the offshore wind farm HVDC transmission system under AC asymmetric faults. A two-stage improved control strategy for MMC-HVDC offshore converter station in response to asymmetric faults has been proposed, which is beneficial for the joint system to quickly recover from the post fault system voltage and suppress the overvoltage risk during the fault clearing phase. Finally, the proposed strategy is validated based on a domestic ± 500kV project in China, demonstrating its effectiveness.

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Effect of Heat and Cryogenic Treatments on the Microstructure and Properties of Yf3 Modified Niti-Si Laser Cladding Coatings

SSRN

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SSRN 2022年

作者： Su, Wennan Zhang, Chi Cui, Xiufang Jin, Guo Liu, Changhao Liu, Erbao Li, Jian Zhao, Haonan Cao, Boyu Tian, Haoliang Institute of Surface/Interface Science and Technology Key Laboratory of Superlight Material and Surface Technology Ministry of Education College of Material Science and Chemical Engineering Harbin Engineering University Harbin150001 China Aviation Key Laboratory of Science and Technology on Advanced Corrosion and Protection for Aviation Material Beijing Beijing Institute of Aeronautical Materials Beijing100095 China

YF 3 modification NiTi-Si coatings were prepared on Ti6Al4V substrate by laser cladding. On this foundation, heat and cryogenic treatments were conducted respectively to explore the effect of after-treatment procedures. The consequence of post-treatment methods on the phase constituent, microstructure, mechanical property, and phase transition characteristics of post-treatment coatings was studied. The phase constituent of the three coatings is roughly the same, composed of NiTi and NiTi 2 . Simultaneously, eutectic structures were found in three coatings, which also proved that the post-treatment would not affect the appearance of the eutectic structure. The results show that heat treatment led to the coarsening of the grain size of the NiTi phase, and the composition of Si element in the NiTi 2 phase increased. On the contrary, the cryogenic treatment led to the refinement of grains and eutectic structure in the coatings. In addition, due to the rapid cooling rate provided by cryogenic treatment, the spinodal decomposition of the Si element occurred in the NiTi 2 phase, which was confirmed by TEM and EDS. The microhardness of the three coatings is as follows: cryogenic treatment>original coatings>heat treatment. The cryogenic treatment coating has the highest microhardness due to grain refinement and spinodal decomposition. Furthermore, the post-treatments also affected the phase transformation characteristics of the coatings. © 2022, The Authors. All rights reserved.

关键词： Coatings

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Observation of molecular and polymeric nitrogen stuffed NaCl ionic layers

arXiv

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arXiv 2025年

作者： Ning, Ping Tian, Yifan Liu, Guangtao Wang, Hongbo Hu, Qingyang Liu, Hanyu Zhou, Mi Ma, Yanming Key Laboratory of Material Simulation Methods and Software Ministry of Education College of Physics Jilin University Changchun130012 China State Key Laboratory of Superhard Materials College of Physics Jilin University Changchun130012 China Center for High Pressure Science and Technology Advanced Research Beijing100094 China International Center of Future Science Jilin University Changchun130012 China

Sodium chloride (NaCl), a ubiquitous and chemically stable compound, has been considered inert under ambient conditions. Its typical B1 structure is highly isotropic without preferential direction, favoring the growth of a three-dimensional network of strong Na-Cl ionic bonds. Here, we employ first-principles structural searching and synchrotron X-ray diffraction to unravel an unexpected chemical reaction between NaCl and N2 to produce a hybrid salt-NaCl(N2)2, where N2 molecules break the isotropic NaCl structure into two-dimensional layers upon synthesis at 50 GPa. In contrast to the insulating properties of pristine NaCl, the electronic bandgap of the N2-stuffed NaCl narrowed to 1.8 eV, becoming an indirect bandgap semiconductor. Further compression to 130 GPa induced the polymerization of N atoms into zigzag N-chains. Our findings not only demonstrate the possibility of unusual N-chemistry under extreme conditions, but also suggest a feasible approach for the design of layered NaCl frameworks to modulate the polymerization of nitrogen. Copyright © 2025, The Authors. All rights reserved.

关键词： Sodium chloride

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Urban constructed wetlands: Assessing ecosystem services and disservices for safe, resilient, and sustainable cities

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Frontiers of Engineering Management 2023年第4期10卷 582-596页

作者： Aamir Mehmood SHAH Gengyuan LIU Yu CHEN Qing YANG Ningyu YAN Feni AGOSTINHO Cecilia MVBALMEIDA Biagio FGIANNETTI State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentBeijing Normal UniversityBeijing 100875China Beijing Engineering Research Center for Watershed Environmental Restoration&Integrated Ecological Regulation Beijing 100875China Advanced Interdisciplinary Institute of Environment and Ecology Beijing Normal UniversityZhuhai 519087China Key Laboratory for City Environmental Safety and Green Development of the Ministry of Education Institute of Environmental and Ecological EngineeringGuangdong University of TechnologyGuangzhou510006China Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou) Guangzhou511458China State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentBeijing Normal UniversityBeijing100875China Programa de Pós-graduação em Engenharia de Produção Laboratório de Produção e Meio AmbienteUniversidade Paulista(UNIP)São Paulo04026-002Brazil

Climate change and rapid urbanization are pressing environmental and social concerns, with approximately 56% of the global population living in urban areas. This number is expected to rise to 68% by 2050, leading to the expansion of cities and encroachment upon natural areas, including wetlands, causing their degradation and fragmentation. To mitigate these challenges, green and blue infrastructures (GBIs), such as constructed wetlands, have been proposed to emulate and replace the functions of natural wetlands. This study evaluates the potential of eight constructed wetlands near Beijing, China, focusing on their ecosystem services (ESs), cost savings related to human health, growing/maintenance expenses, and disservices using an emergy-based assessment procedure. The results indicate that all constructed wetlands effectively purify wastewater, reducing nutrient concentrations (e.g., total nitrogen, total phosphorus, and total suspended solids). Among the studied wetlands, the integrated vertical subsurface flow constructed wetland (CW-4) demonstrates the highest wastewater purification capability (1.63E+14 sej/m^(2)/yr) compared to other types (6.78E+13 and 2.08E+13 sej/m^(2)/yr). Additionally, constructed wetlands contribute to flood mitigation, groundwater recharge, wildlife habitat protection, and carbon sequestration, resembling the functions of natural wetlands. However, the implementation of constructed wetlands in cities is not without challenges, including greenhouse gas emissions, green waste management, mosquito issues, and disturbances in the surrounding urban areas, negatively impacting residents. The ternary phase diagram reveals that all constructed wetlands provide more benefits than costs and impacts. CW-4 shows the highest benefit-cost ratio, reaching 50%, while free water surface constructed wetland (CW-3) exhibits the lowest benefits (approximately 38%), higher impacts (approximately 25%), and lower costs (approximately 37%) compared to other we

关键词： constructed wetland emergy ecosystem services disservices ternary diagram

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