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Repair tolerance assessment for aircraft composite structures using Bayesian updating

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Chinese Journal of Aeronautics 2024年第6期37卷 360-391页

作者： Xin LI Hongfu zuo Bin yang School of Automotive and Rail Transit Nanjing Institute of TechnologyNanjing 211167China Civil Aviation Key Laboratory of Aircraft Health Monitoring and Intelligent Maintenance College of Civil AviationNanjing University of Aeronautics and AstronauticsNanjing 211106China

Detection and repair of composite damage is crucial to ensure the safety and reliability of aircraft structures.A novel approach to quantitatively evaluate the repair tolerance of composite structures in civil aircraft based on Bayesian updating is *** method incorporates historical damage inspection data to determine the prior distribution of damage size,which is then updated with newly collected damage size data using Bayesian *** Carlo simulation is employed to investigate the probability of failure and estimate maintenance costs,considering various factors such as the frequency and timing of damage events,damage detection,structural strength,gust loads,and maintenance expenses throughout the lifecycle of composite *** and economic factors are considered to establish a lower threshold for repairs and an upper threshold for maintenance based on the occurrence of accidental impact *** of the effectiveness and feasibility of a quantitative assessment method for repair tolerance is conducted using damage statistics data from civil aircraft routes utilizing the structural skin panels of composite outer *** results demonstrate that the method proposed in conjunction with extensive simulations and full utilization of field damage inspection data can effectively simulate unexpected impact damage situations that may occur during civil aircraft service and evaluate the reliability and economic feasibility of the repair of *** research findings hold significant theoretical and practical value for the preparation of documents for continued airworthiness of composite structures,including structural repair manuals and maintenance programs.

关键词： Composite structures Repair tolerance Maintenance Bayesian updating Probability of failure

Byzantine Robust Federated Learning Scheme Based on Backdoor Triggers

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Computers, Materials & Continua 2024年第5期79卷 2813-2831页

作者： Zheng yang Ke Gu Yiming zuo School of Computer and Communication Engineering Changsha University of Science and TechnologyChangsha410114China

Federated learning is widely used to solve the problem of data decentralization and can provide privacy protectionfor data owners. However, since multiple participants are required in federated learning, this allows attackers tocompromise. Byzantine attacks pose great threats to federated learning. Byzantine attackers upload maliciouslycreated local models to the server to affect the prediction performance and training speed of the global model. Todefend against Byzantine attacks, we propose a Byzantine robust federated learning scheme based on backdoortriggers. In our scheme, backdoor triggers are embedded into benign data samples, and then malicious localmodels can be identified by the server according to its validation dataset. Furthermore, we calculate the adjustmentfactors of local models according to the parameters of their final layers, which are used to defend against datapoisoning-based Byzantine attacks. To further enhance the robustness of our scheme, each localmodel is weightedand aggregated according to the number of times it is identified as malicious. Relevant experimental data showthat our scheme is effective against Byzantine attacks in both independent identically distributed (IID) and nonindependentidentically distributed (non-IID) scenarios.

关键词： Federated learning Byzantine attacks backdoor triggers

Homogenizing interfacial shear stress in brick-and-mortar structured composites via gradient modulus for enhanced mechanical properties

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Acta Mechanica Sinica 2024年第6期40卷 115-124页

作者： yang Gao jiawei He jie jiang jianping zuo School of Mechanics and Civil Engineering China University of Mining and Technology(Beijing)Beijing100083China

Inspired by nature,various biomimetic materials have been synthesized for enhanced mechanical properties,among which composites with brick-and-mortar structures attract the most *** such bio-inspired composites,the matrix layer mainly functions to transfer load between bricks through shearing,while the shear stress in the matrix is not uniform but highly concentrated on the interface ends,which tends to initiate cracks and evoke interface delamination in *** enhance the composites’resistance to interface delamination,we propose to homogenize the shear stress by adopting a matrix with a gradient modulus.A theoretical solution to the optimal gradient modulus of the matrix layer is obtained,followed by computational ***,composites with such functionally graded matrices are further demonstrated to possess higher elastic limits,higher resilience,and flaw tolerance than the uniform *** results of this paper should be of great value to the design and synthesis of advanced structural materials for superior mechanical performance.

关键词： Stress concentration Interface delamination Brick-and-mortar structure Composite

Role of Oncostatin M in the prognosis of inflammatory bowel disease: A meta-analysis

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World Journal of Gastrointestinal Surgery 2024年第1期16卷 228-238页

作者： Yue yang Kan-zuo Fu Gu Pan Department of Gastroenterology III Heilongjiang Provincial HospitalHarbin 150036Heilongjiang ProvinceChina Department of Nursing The Second Hospital of HarbinHarbin 150056Heilongjiang ProvinceChina

BACKGROUND Oncostatin M(OSM)is a pleiotropic cytokine which is implicated in the path-ogenesis of inflammatory bowel disease(IBD).AIM To evaluate the prognostic role of OSM in IBD *** Literature search was conducted in electronic databases(Google Scholar,Embase,PubMed,Science Direct,Springer,and Wiley).Studies were selected if they reported prognostic information about OSM in IBD *** data were synthesized,and meta-analyses were performed to estimate standardized mean differences(SMDs)in OSM levels between treatment responders and non-res-ponders and to seek overall correlations of OSM with other inflammatory *** Sixteen studies(818 Crohn’s disease and 686 ulcerative colitis patients treated with anti-tumor necrosis factor-based therapies)were *** levels were associated with IBD severity.A meta-analysis found significantly higher OSM levels in non-responders than in responders to therapy[SMD 0.80(0.33,1.27);P=0.001],in non-remitters than in remitters[SMD 0.75(95%CI:0.35 to 1.16);P<0.0001]and in patients with no mucosal healing than in those with mucosal heal-ing[SMD 0.63(0.30,0.95);P<0.0001].Area under receiver operator curve values showed considerable variability between studies but in general higher OSM levels were associated with poor *** had significant correlations with Simple Endoscopic Score of Crohn’s disease[r=0.47(95%CI:0.25 to 0.64);P<0.0001],Mayo Endoscopic Score[r=0.35(95%CI:0.28 to 0.41);P<0.0001],fecal calprotectin[r=0.19(95%CI:0.08 to 0.3);P=0.001],C-reactive protein[r=0.25(95%CI:0.11 to 0.39);P<0.0001],and platelet count[r=0.28(95%CI:0.17 to 0.39);P<0.0001].CONCLUSION OSM is a potential candidate for determining the severity of disease and predicting the outcomes of anti-tumor necrosis factor-based therapies in IBD patients.

关键词： Inflammatory bowel disease Crohn’s disease Ulcerative colitis Oncostatin M Prognosis

Analysis of explosion wave interactions and rock breaking effects during dual initiation

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International Journal of Minerals,Metallurgy and Materials 2024年第8期31卷 1788-1798页

作者： Renshu yang jinjing zuo Liwei Ma Yong Zhao Zhen Liu Quanmin Xie School of Civil and Resource Engineering University of Science and Technology BeijingBeijing 100083China Research Institute of Macro-Safety Science University of Science and Technology BeijingBeijing 100083China State Key Laboratory of Precision Blasting Jianghan UniversityWuhan 430056China

In blasting engineering, the location and number of detonation points, to a certain degree, regulate the propagation direction ofthe explosion stress wave and blasting effect. Herein, we examine the explosion wave field and rock breaking effect in terms of shockwave collision, stress change of the blast hole wall in the collision zone, and crack propagation in the collision zone. The produced shockwave on the collision surface has an intensity surpassing the sum of the intensities of the two colliding explosion shock waves. At the collisionlocation, the kinetic energy is transformed into potential energy with a reduction in particle velocity at the wave front and the wavefront pressure increases. The expansion form of the superposed shock wave is dumbbell-shaped, the shock wave velocity in the collisionarea is greater than the radial shock wave velocity, and the average propagation angle of the explosion shock waves is approximately 60°.Accordingly, a fitted relationship between blast hole wall stress and explosion wave propagation angle in the superposition area is *** the experimental conditions, the superimposed explosion wave stress of the blast hole wall is approximately 1.73 times the singleexplosionwave incident stress. The results of the model test and numerical simulations reveal that large-scale radial fracture cracks weregenerated on the blast hole wall in the superimposed area, and the width of the crack increased. The width of the large-scale radial fracturecracks formed by a strong impact is approximately 5% of the blast hole length. According to the characteristics of blast hole wallcompression, the mean peak pressures of the strongly superimposed area are approximately 1.48 and 1.84 times those of the weakly superimposedand nonsuperimposed areas, respectively.

关键词： blasting shock wave collision high-speed schlieren system crack fracture characteristic explosion wave

Oxidation Resistance of In Situ Reaction/Hot Pressing Synthesized Ti_(2)AlC-20%TiB_(2) Composite at 600-900℃in Air

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Acta Metallurgica Sinica(English Letters) 2024年第4期37卷 739-748页

作者： Wenting Wang jingjun Xu Jun zuo Ke Ma yang Li Guangqi He Meishuan Li Shengyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang110016China

The oxidation behavior and kinetics of Ti_(2)AlC-20vol.%TiB_(2) composite at 600-900℃ in air were *** results showed that the oxidation kinetics of the composite followed a logarithmic law within the given temperature range,which indicated that the composites had excellent oxidation *** selective oxidation of Al in Ti_(2)AlC was greatly enhanced,which facilitated the formation of a continuous and dense protective layer of Al_(2)O_(3).Meanwhile,the existence of molten B_(2)O_(3) inhibited the outward diffusion of Ti and inward diffusion of oxygen,which prevented the growth of anatase TiO_(2) at 600℃ and rutile TiO_(2) at 700-900℃.Therefore,the incorporation of TiB_(2) completely inhibited the abnormally rapid oxidation of bulk Ti_(2)AlC at 600℃ and improved its oxidation resistance at 700-900℃.

关键词： MAX phase Ti_(2)AlC-TiB_(2)composite Intermediate temperature oxidation Oxidation kinetics

Linearized waveform inversion for vertical transversely isotropic elastic media:Methodology and multi-parameter crosstalk analysis

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Petroleum Science 2024年第1期21卷 252-271页

作者： Ke Chen Lu Liu Li-Nan Xu Fei Hu Yuan yang jia-Hui zuo Le-Le Zhang yang Zhao National Key Laboratory of Petroleum Resources and Engineering Unconventional Petroleum Research InstituteChina University of Petroleum(Beijing)Beijing102249China Aramco Beijing Research Center Aramco AsiaBeijing100102China University of Lausanne LausanneCH-1015Switzerland Bureau of Geophysical Prospecting China National Petroleum CorporationZhuozhou 072750HebeiChina

Seismic migration and inversion are closely related techniques to portray subsurface images and identify hydrocarbon *** migration aims at obtaining structural images of subsurface geologic *** specifically,seismic migration estimates the reflectivity function(stacked average reflectivity or pre-stack angle-dependent reflectivity)from seismic reflection *** the other hand,seismic inversion quantitatively estimates the intrinsic rock properties of subsurface *** seismic inversion methods are applicable to detect hydrocarbon reservoirs that may exhibit lateral variations in the inverted *** there exist many differences,pre-stack seismic migration is similar with the first iteration of the general linearized seismic ***,seismic migration and inversion techniques assume an acoustic or isotropic elastic *** reservoirs such as shale and tight sand formation have notable anisotropic *** present a linearized waveform inversion(LWI)scheme for weakly anisotropic elastic media with vertical transversely isotropic(VTI)*** is based on two-way anisotropic elastic wave equation and simultaneously inverts for the localized perturbations(ΔVp_(0)/Vp_(0)/Vs_(0)/Vs_(0)/,Δ∈,Δδ)from the long-wavelength reference *** proposed VTI-elastic LWI is an iterative method that requires a forward and an adjoint operator acting on vectors in each *** derive the forward Born approximation operator by perturbation theory and adjoint operator via adjoint-state *** inversion has improved the quality of the images and reduces the multi-parameter crosstalk comparing with the adjoint-based *** have observed that the multi-parameter crosstalk problem is more prominent in the inversion images for Thomsen anisotropy ***,the Thomsen parameter is the most difficult to *** also analyze the multi-parameter crosstalk using scattering radiation patte

关键词： Elastic Anisotropy Least-squares imaging Waveform inversion Computational geophysics

Progress and prospects of pH-neutral aqueous organic redox flow batteries:Electrolytes and membranes

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Journal of Energy Chemistry 2024年第9期96卷 89-109页

作者： Kang Peng Gonggen Tang Chao Zhang Xian yang Peipei zuo Zhanfeng Xiang Zhong Yao Zhengjin yang Tongwen Xu Key Laboratory of Precision and Intelligent Chemistry Department of Applied ChemistrySchool of Chemistry and Materials ScienceUniversity of Science and Technology of ChinaHefei 230026AnhuiChina Suqian Time Energy Storage Technology Co. Ltd.Suqian 223800JiangsuChina

Aqueous organic redox flow batteries(AORFBs),which exploit the reversible electrochemical reactions of water-soluble organic electrolytes to store electricity,have emerged as an efficient electrochemical energy storage technology for the grid-scale integration of renewable ***-neutral AORFBs that feature high safety,low corrosivity,and environmental benignity are particularly promising,and their battery performance is significantly impacted by redox-active molecules and ion-exchange membranes(IEMs).Here,representative anolytes and catholytes engineered for use in pH-neutral AORFBs are outlined and summarized,as well as their side reactions that cause irreversible battery capacity *** addition,the recent achievements of IEMs for pH-neutral AORFBs are discussed,with a focus on the construction and tuning of ion transport ***,the critical challenges and potential research opportunities for developing practically relevant pH-neutral AORFBs are presented.

关键词： Aqueous organic redox flow battery pH-Neutral Anolyte Catholyte Membrane

Facile synthesis of W-Mo bimetallic oxides with high adsorption properties from secondary resources

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Tungsten 2024年第4期6卷 806-820页

作者： jia-Li Cheng yang-Si Liu Xiao-Li Xi zuo-Ren Nie Collaborative Innovation Center of Capital Resource-Recycling Material Technology College of Materials Science and Engineering Beijing University of Technology National Engineering Laboratory for Industrial Big-Data Application Technology Beijing University of Technology Key Laboratory of Advanced Functional Materials Ministry of Education Beijing University of Technology

A simple solvothermal method was used to obtain W-Mo bimetallic oxides from W-Mo alloy scrap,and pure metal powders were also used as the raw materials to simulate *** products had a sea urchin-like structure with abundant oxygen vacancies and the products prepared at low temperatures forms a sosoloid resembling orthorhombic *** WMo bimetallic oxide prepared at the reaction temperature of 120 ℃ exhibited excellent selective adsorption performance for methylene blue（MB）,which the adsorption rate of MB reached 99% in 12 min and the adsorption rate reached 90% after6 adsorption *** the W-Mo molar ratio is 1:3,the maximum adsorption capacity of sample for MB can reach1148 mg·*** adsorption process followed the Langmuir and pseudo-second-order models,which is surface-controlled monolayer *** experimental results show the feasibility of preparing W-Mo bimetal oxide products from pure materials and *** process is simple and effective,which offered a potential approach for secondary resource recycling and reusing.

关键词： Oxygen vacancy Selective adsorption Solvothermal W–Mo alloy scrap W–Mo bimetallic oxide