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The effects of solute and deformation on the mobility of screw dislocation cores in bcc molybdenum

MOdELLING ANd SIMULATION IN MATErIALS SCIENCE ANd ENGINEErING 2025年第3期33卷 035007-035007页

作者： Zhou, Kangzhi Feng, Jiajun Liu, Ziran deng, Huiqiu Jia, Lixia He, Xinfu Hunan Normal Univ Key Lab Low Dimens Quantum Struct & Quantum Contro Key Lab Matter Microstruct & Funct Hunan Prov Minist EducDept Phys Changsha 410081 Hunan Peoples R China Hunan Normal Univ Inst Interdisciplinary Studies Changsha 410081 Hunan Peoples R China Hunan Univ Sch Phys & Elect Hunan Prov Key Lab High Energy Scale Phys & Applic Changsha 410082 Peoples R China China Inst Atom Energy Div Reactor Engn Technol Res Beijing 102413 Peoples R China

In body-centered cubic metals such as molybdenum, screw dislocations critically govern the plastic deformation behavior of alloys. The presence of solute atoms in alloys can effectively alter the formation and movement of screw dislocations. In this study, we employed first-principles calculations to delve into the electronic origins of these influences. Initially, we constructed single atomic column and triple atomic column models to simulate the formation of screw dislocations with solute atoms. Our investigation revealed that tantalum (Ta) and tungsten (W) increase the formation energy of solute-dislocation interactions, while osmium (Os), iridium (Ir), and platinum (Pt) have the opposite effect. Subsequently, utilizing a screw dislocation dipole model under shear deformation, we explored the combined effects of solute atoms and deformation on dislocation core movement. We found that Os, Ir, and Pt, located as the first nearest neighbors of the dislocation core, exhibit an attractive effect on the dislocation core. Solute atoms at specific positions can alter the direction of dislocation slip, inducing cross-slip and enhancing material ductility. In contrast, under the same stress, Ta and W exhibit repulsion towards the dislocation core and cannot change the direction of dislocation slip, only altering the energy barrier for dislocation core movement. This work provides atomic-scale insights into solute-induced dislocation dynamics, offering guidelines for advanced Mo alloy design.

关键词： screw dislocation molybdenum first-principles calculations

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Bivariate degradation modeling and reliability analysis based on generalized nonlinear Wiener processes and a shared frailty factor

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QUALITY ANd rELIABILITY ENGINEErING INTErnational 2025年第2期41卷 854-871页

作者： Li, Lu Wang, Zhihua Wu, Qiong Mao, Zelong Liu, Chengrui Beihang Univ Sch Aeronaut Sci & Engn Natl Key Lab Strength & Struct Integr Beijing Peoples R China China Acad Space Technol Inst Spacecraft Syst Engn Beijing Peoples R China China State Shipbuilding Corp Ltd Nav Instrument Res Inst Tianjin Peoples R China China Acad Space Technol Beijing Inst Control Engn Beijing Peoples R China

The complexity of product functionality and composition often involves at least two or more interrelated performance characteristics jointly reflecting the degradation. At the same time, the intricacy of the underlying failure mechanisms often results in degradation processes exhibiting intricate nonlinear patterns, where the mean and variance can display different nonlinear behaviors. Additionally, the random effect of the degradation process should not be overlooked. Therefore, an accurate depiction of degradation regulation is a crucial prerequisite for reasonable model construction and effective reliability analysis. To settle the challenges posed by complex nonlinear scenarios, this paper proposes a bivariate degradation model based on generalized nonlinear Wiener processes, incorporating a shared frailty factor to characterize the correlation between performance features. An approximate analytical expression for the cumulative distribution function of the first hitting time is derived for reliability analysis. Furthermore, unknown parameter estimation is carried out through a combination of the expectation-maximization algorithm and the genetic algorithm. Finally, the effectiveness of the proposed model and reliability analysis method is validated through a comprehensive simulation investigation and a practical case study involving fatigue crack propagation.

关键词： bivariate degradation expectation maximization algorithm frailty factor first hitting time generalized nonlinear Wiener process

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Multimaterial Topology Optimization Method of Surface-Mounted PMSM rotor Poles Based on Variable density representation

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IEEE-ASME TrANSACTIONS ON MECHATrONICS 2025年第1期30卷 436-446页

作者： He, Xinghua Yan, Liang Xiang, Pengjie du, Nannan Liu, Xiaoshuai Chen, I-Ming Hu, Haifeng Beihang Univ Sch Automat Sci & Elect Engn Beijing 100191 Peoples R China Beihang Univ Sch Automat Sci & Elect Engn Sci & Technol Aircraft Control Lab Beijing 100191 Peoples R China Beihang Univ Ningbo Inst Technol Ningbo 315800 Peoples R China Nanyang Technol Univ Sch Mech & Aerosp Engn Singapore 639798 Singapore Inst Beijing Aerosp Automatic Control Inst Beijing 100854 Peoples R China Natl Key Lab Aerosp Intelligence Control Beijing 100854 Peoples R China

Conventionally, the designers of electrical machines assume the employment of regular shaped magnets, such as rectangular, sector, or tiled-shapes. The geometry of magnet poles is fixed, and the design purpose is mainly to optimize the dimensional values. However, these regular shapes employed may not be the best choice, unavoidably limiting the final design result, and compromising the output performance of the electrical machines. An alternative scheme is to conduct topology optimization for rotor poles. By this method, the geometrical shape of magnets along with the iron core is no longer fixed, but automatically obtained through the optimal distribution of materials, such as iron, magnet, and air. It helps to achieve better optimization results with less shape constrains. Therefore, this article proposes a multimaterial topology optimization method based on variable density representation for surface-mounted permanent-magnet synchronous motor to obtain an optimal rotor pole pattern, and thus improve the output performance of electrical machines, especially the torque density, which is crucial in aerospace industry. The computational speed is increased by improving the objective function and the arbitrary volume constraints become clear by combining size and topology optimization. To validate the design method, theoretical, numerical and experimental studies are conducted. First, the operating principle, design variables, constrains, optimization objective, and procedure of the method are introduced in detail. Then, the optimization method is implemented into the rotor design of one surface-mounted electric machine, and the result is presented and discussed. Subsequently, the magnetic flux density and torque output of electric machine with the optimized rotor poles is compared with conventional design, and it shows that the former can achieve better output performance relatively. Finally, one research prototype of the electrical machine is developed, and experime

关键词： Magnetic pole pattern permanent-magnet synchronous motor (PMSM) surface-mounted pole topology optimization torque density

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Investigation on the recovery of rare Earth Fluorides from Spent rare Earth Molten Electrolytic Slag by Vacuum distillation

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MATErIALS 2025年第7期18卷 1538-1538页

作者： Yang, Ziyan Xiao, Faxin Sun, Shuchen Tu, Ganfeng Zhou, Zhentao Chen, Jingyi Hong, Xin He, Wei Sui, Chengfu Yu, Kuopei Northeastern Univ Sch Met Shenyang 110819 Peoples R China Key Lab Recycling Nonferrous Met Resources Shenyan Shenyang 110819 Peoples R China Qingdao Qingli Environm Protect Equipment Co Ltd Qingdao 266300 Peoples R China

Spent rare earth molten salt electrolytic slag (rEMES) needs to be recovered not only because of its economic value of rare earth elements (rEEs), lithium, and fluorine, but also for the environmental benefits. Vacuum distillation has many advantages, such as a short process and less wastewater. Aiming to find an environmentally friendly method to recover rEEs, this research studied the challenges in recovering rEMES by vacuum distillation and the solutions to handle these obstacles. distillation experiments for the raw material were initially implemented and Xrd, XPS, dSC, and SEM methods were used to investigate the phase changes of rEMES, thus discovering that oxide impurities could transform rEF3 into rEOF, which significantly affected the rEEs recovery. Only 42.04% of the rEEs could be evaporated at 1573 K and 0.1 Pa for 4 h with 99.99% of LiF. To tackle this issue, a fluorination pretreatment was proposed. NH4HF2 was utilized to transform oxide impurities, rE2O3, and rEOF to fluorides with almost no waste gas released, significantly improving the recovery efficiency of the rEEs, which was 86.23%. Therefore, this paper proposes this fluorination-vacuum distillation method, which has a short process to recover rEF3 from rEMES efficiently with almost no wastewater or gas released.

关键词： rare earth molten electrolytic slag rare earth fluorides vacuum distillation recycling

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Nitrogen cycling and functional gene diversity of drinking reservoir area in agricultural districts: Implications for nitrogen transformation processes

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ECOLOGICAL INdICATOrS 2025年 173卷

作者： Li, Mengze Wang, Wenwen Yuan, Shengwu Wang, Kun Wang, Shuhang Li, Wei Jiang, Xia Zhang, Wenqiang Shan, Baoqing North China Elect Power Univ Coll Environm Sci & Engn MOE Key Lab Resources & Environm Syst Optimizat Beijing 102206 Peoples R China Chinese Res Inst Environm Sci Natl Engn Lab Lake Pollut Control & Ecol Restorat State Environm Protect Key Lab Lake Pollut Control Beijing 100012 Peoples R China Chinese Acad Sci Res Ctr Ecoenvironm Sci State Key Lab Environm Aquat Chem Beijing 100085 Peoples R China

Nitrogen pollution in aquatic ecosystems, especially in shallow lakes and reservoirs, has intensified in recent years due to human activities like agricultural fertilization and wastewater discharge. However, the microbial mechanisms driving nitrogen cycling are not well understood. This study examines nitrogen migration, transformation, and the microbial mechanisms driving nitrogen cycling in the QuanMin reservoir, which is heavily influenced by agricultural activities and land runoff. The reservoir serves as a model for understanding nitrogen pollution, and its effects on water quality. The results indicate that total nitrogen (TN) concentrations in the overlying water ranged from 0.43 to 2.22 mg/L, with nitrate nitrogen accounting for an average of 52 % of the total. Nitrogen cycling was mainly driven by key genes involved in assimilatory nitrate reduction to ammonium and denitrification, with notable differences in gene abundance between river and reservoir waters. denitrification genes were dominant in the sediments, and reservoir sediments showed a higher potential for nitrogen fixation than river sediments. Additionally, nitrate concentrations were significantly higher in riverine waters, while TN and total carbon levels in sediments were notably lower in the reservoir compared to the river. These environmental parameters were closely associated with the abundance of nitrogen functional genes in water and sediment. These findings advance mechanistic understanding of microbial nitrogen cycling in anthropogenically impacted reservoirs. Nonetheless, the complexity and variability of nitrogen cycling in these reservoirs highlight the need for further targeted research to enhance understanding and improve management practices.

关键词： Agricultural reservoir Nitrogen cycling Functional genes Eutrophication Sediment Nitrogen transformation

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The failure mode and fracture morphology of shale under dry and water fracturing situation

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PHYSICS OF FLUIdS 2025年第2期37卷

作者： Wang, Xiaoqiong Ge, Juntao ren, Qinpei Huang, Keke Ge, Hongkui China Univ Petr Unconvent Petr Res Inst Beijing 102249 Peoples R China

Hydraulic fracturing is an essential means to achieve economic benefits for shale oil and gas, with the main goal of forming complex fracture networks. Water-based fracturing fluid is a commonly used fracturing fluid. Gas bearing shale has special rock physical properties, such as microcracks development and high clay minerals, which will inevitably lead to physical and chemical interaction between shale and water-based fracturing fluid, and affect the failure mode and fracture morphology. In this paper, Lujiaping Formation shale in Chongqing area, southwest of china is selected for the compression experiments under dry and water fracturing condition, respectively. Through the analysis of mechanical parameters, deformation characteristics, the influence of water on the failure mode and fracture morphology is systematically studied. The experimental results indicate that both dry shale and water fracturing shale have shear localization bands, with dry shale one shear band and water shale several shear bands (main fracture), which is different from previous study that water saturated shale forms a dispersed fracture network without a main fracture. In fact, the marine shale of the Lujiaping Formation has a strong spontaneous imbibition ability. When shale is saturated with water, the water absorbed into shale increases pore pressure (reducing normal stress), which leads to further propagation of microcracks and increases the initial microcrack volume. The increase in initial crack volume will enhance the interaction between cracks. In addition, the water entering the cracks further reduces the friction resistance between crack surfaces, making the cracks prone to shear sliding, dilatation and forming several shear bands. The widely developed initial microcracks connect various shear bands, forming a more complex fracture network that increase the overall deformation width of the sample compared to dry sample.

关键词： Fracturing fluids

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Transforming liquid flow fuel cells to controllable reactors for highlyefficient oxidation of 5-hydroxymethylfurfural to 2, 5-furandicarboxylic acid at low temperature

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Journal of Energy Chemistry 2024年第3期90卷 621-631,I0014页

作者： Ye Qiang Xi Liu denghao Ouyang Zhao Jiang Xuebing Zhao Key Laboratory of Industrial Biocatalysis Ministry of EducationTsinghua UniversityBeijing 100084China Institute of Applied Chemistry Department of Chemical EngineeringTsinghua UniversityBeijing 100084China School of Chemical Engineering and Technology Xi'an Jiaotong UniversityXi'an 710049ShaanxiChina

Highly-efficient oxidation of 5-hydroxymethylfurtural(HMF) to 2,5-furandicarboxylic acid(FdCA) at low temperature with air as the oxidant is still ***,inspired by the respirato ry electron transport chain(ETC) of living cells mediated by electron carriers,we constructed artificial ETCs and transformed liquid flow fuel cells(LFFCs) to flexible reactors for efficient oxidation of HMF to produce FdCA under mild *** LFFC reactor employed an electrodeposition modified nickel foam as an anode to promote HMF oxidation and(VO_(2))_(2)SO_(4) as a cathode electron carrier to facilitate the electron transfer to *** reaction rate could be easily controlled by selecting the anode catalyst,adjusting the external loading and changing the cathodic electron carrier or oxidants.A maximal power density of 44.9 mW cm^(-2) at room temperature was achieved,while for FdCA production,short-circuit condition was preferred to achieve quick transfer of *** a single batch operation with 0.1 M initial HMF,FdCA yield reached 97.1%.By fed-batch operation,FdCA concentration reached 144.5 g L^(-1) with a total yield of 96%.Ni^(2+)/Ni^(3+) redox couple was the active species mediating the electron transfer,while both experimental and dFT calculation results indicated that HMFCA pathway was the preferred reaction mechanism.

关键词： 5-Hydroxymethylfurfural 2 5-Furandicarboxylic acid Electrodeposition Electron transport chain Liquid flow fuel cell

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Iterative and mixed‑spaces image gradient inversion attack in federated learning

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Cybersecurity 2025年第2期8卷 292-305页

作者： Linwei Fang Liming Wang Hongjia Li Institute of Information Engineering Chinese Academy of SciencesBeijingChina School of Cyber Security University of Chinese Academy of SciencesBeijingChina

As a distributed learning paradigm,federated learning is supposed to protect data privacy without exchanging users’local *** so,the gradient inversion attack,in which the adversary can reconstruct the original data from shared training gradients,has been widely deemed as a severe ***,most existing researches are confined to impractical assumptions and narrow range of *** mitigate these shortcomings,we propose a comprehensive framework for gradient inversion attack,with well-designed algorithms for image and label *** image reconstruction,we fully utilize the generative image prior,which derives from wide-used generative models,to improve the reconstructed results,by additional means of iterative optimization on mixed spaces and gradientfree *** label reconstruction,we design an adaptive recovery algorithm regarding real data distribution,which can adjust previous attacks to more complex ***,we incorporate a gradient approximation method to efficiently fit our attack for FedAvg *** empirically verify our attack framework using benchmark datasets and ablation studies,considering loose assumptions and complicated *** hope this work can greatly reveal the necessity of privacy protection in federated learning,while urge more effective and robust defense mechanisms.

关键词： Privacy preserving Federated learning Gradient inversion

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Online dynamic Fault diagnosis for rotor System Based on degradation Modeling and Knowledge-Enhanced Graph Convolutional Network

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IEEE-ASME TrANSACTIONS ON MECHATrONICS 2025年第1期30卷 703-714页

作者： Ma, Leiming Jiang, Bin Lu, Ningyun Xiao, Lingfei Nanjing Univ Aeronaut & Astronaut Coll Automat Engn Nanjing 210016 Peoples R China Nanjing Univ Aeronaut & Astronaut Coll Energy & Power Engn Nanjing 210016 Peoples R China

The coupling analysis of model performance degradation and fault diagnosis under variable working states, known as dynamic fault diagnosis, is widely recognized as urgent need. The inadequate exploration of missing labeled samples and the intricate connection between degradation signals and fault signals has resulted in limited research on these issues. Therefore, it is necessary to design an effective method that can be used for degradation state identification and cross-domain dynamic fault diagnosis. This article proposes a novel strategy based on the optimized linear parameter-varying model and knowledge-enhanced graph convolutional adversarial network (KEGCAN). First, a degradation simulation model of the rotor system is established by analyzing the changes in contact stiffness and support stiffness caused by bolt loosening and bearing wear, respectively. Then, the proposed KEGCAN is developed based on prior knowledge from the time-frequency features of simulation data, taking advantage of the powerful capabilities of simulation model and graph convolutional network. Finally, high-precision cross-domain online dynamic fault diagnosis is achieved using both experimental data collected from the rotor system test rig and simulation data collected from the degradation simulation model. The results indicate that the proposed strategy has better diagnosis accuracy than the state-of-the-art algorithms.

关键词： degradation Fault diagnosis rotors Analytical models data models Heuristic algorithms Fasteners degradation modeling fault diagnosis few-shot graph convolutional network (GCN) rotor system

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Achieving highly efficient long-wavelength phosphorescence emission of large singlet-triplet energy gap materials by host-guest doping

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Science china Chemistry 2024年第6期67卷 1922-1928页

作者： Shasha Zhang Wei Yao Anqi Lv Kun Liu Yusheng Zhang Chifeng Zhou Huili Ma Huifang Shi Zhongfu An Key Laboratory of Flexible Electronics(KLOFE)&Institute of Advanced Materials(IAM) Nanjing Tech UniversityNanjing211816China

High-efficiency long-wavelength phosphorescence emissions of large singlet-triplet energy gap(ΔE_(ST))materials are essential for applications in biology and ***,few long-wavelength phosphorescence emissions of largeΔE_(ST)materials have been reported due to the weak spin-orbit coupling(SOC)and strong non-radiative ***,we develop a strategy to achieve highly efficient long-wavelength room temperature phosphorescence(rTP)emission of largeΔE_(ST)materials,which display bright red rTP emission with above 400μs lifetime and 6.5%phosphorescent quantum *** experiments and theoretical calculations reveal that the fishbone-like packing and the zig-zag interactions provide favorable conditions for suppressing the non-radiative transitions of triplet state excitons,and heavy atoms effectively promote the intersystem crossing(ISC)process for highly efficient long-wavelength phosphorescence *** universality of the method for highly efficient long-wavelength rTP emission of largeΔE_(ST)materials was further investigated in various ***,these materials with largeΔE_(ST)manifest the advantages of large color contrast on the display and utilization potentiality in information *** strategy paves the way for the high contrast display and development of information encryption with rTP emission.

关键词： room temperature phosphorescence singlet-triplet energy gap host-guest doping heavy atom effect red phosphorescence

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