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Three-dimensional pseudo-dynamic reliability analysis of seismic shield tunnel faces combined with sparse polynomial chaos expansion

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Journal of Central South University 2024年第6期31卷 2087-2101页

作者： GUO feng-qi LI shi-wei ZOU Jin-feng School of Civil Engineering Central South UniversityChangsha 410075China

To address the seismic face stability challenges encountered in urban and subsea tunnel construction,an efficient probabilistic analysis framework for shield tunnel faces under seismic conditions is *** on the upper-bound theory of limit analysis,an improved three-dimensional discrete deterministic mechanism,accounting for the heterogeneous nature of soil media,is formulated to evaluate seismic face *** metamodel of failure probabilistic assessments for seismic tunnel faces is constructed by integrating the sparse polynomial chaos expansion method(SPCE)with the modified pseudo-dynamic approach(MPD).The improved deterministic model is validated by comparing with published literature and numerical simulations results,and the SPCE-MPD metamodel is examined with the traditional MCS *** on the SPCE-MPD metamodels,the seismic effects on face failure probability and reliability index are presented and the global sensitivity analysis(GSA)is involved to reflect the influence order of seismic action ***,the proposed approach is tested to be effective by a engineering case of the Chengdu outer ring *** results show that higher uncertainty of seismic response on face stability should be noticed in areas with intense earthquakes and variation of seismic wave velocity has the most profound influence on tunnel face stability.

关键词： reliability analysis shield tunnel face sparse polynomial chaos expansion modified pseudo-dynamic approach seismic stability assessment

Counteracting effects on ENSO induced by ocean chlorophyll interannual variability and tropical instability wave-scale perturbations in the tropical Pacific

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Science China Earth Sciences 2024年第2期67卷 387-404页

作者： Rong-Hua ZHANG feng TIAN Qidong shi Xiujun WANG Tongwen WU School of Marine Sciences Nanjing University of Information Science and TechnologyNanjing210044China Laoshan Laboratory Qingdao266237China Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of SciencesQingdao266071China University of Chinese Academy of Sciences Beijing101408China Faculty of Geographical Sciences Beijing Normal UniversityBeijing100875China Earth System Modeling and Prediction Centre China Meteorological AdministrationBeijing100081China

Large perturbations in chlorophyll(Chl)are observed to coexist at interannual and tropical instability wave(TIW)scales in the tropical Pacific;at present,their combined effects on El Ni?o-Southern Oscillation(ENSO)through ocean biologyinduced heating(OBH)feedbacks are not understood ***,a hybrid coupled model(HCM)for the atmosphere and ocean physics-biogeochemistry(AOPB)in the tropical Pacific is adopted to quantify how ENSO can be modulated by Chl perturbations at interannual and TIW scales,individually or collectively,*** HCM-based sensitivity experiments demonstrate a counteracting effect on ENSO:the bio-climate feedback due to large-scale Chl interannual variability acts to damp ENSO through its impact on upper-ocean stratification and vertical mixing,whereas that due to TIW-scale Chl perturbations tends to amplify *** ENSO simulations are sensitively dependent on the ways Chl effects are represented at these different scales,it is necessary to adequately take into account these related differential Chl effects in climate modeling.A bias source for ENSO simulations is illustrated that is related with the Chl effects in the tropical Pacific,adding in a new insight into interactions between the climate system and ocean ecosystem on different scales in the *** results reveal a level of complexity of ENSO modulations resulting from Chl effects at interannual and TIW scales,which are associated with ocean biogeochemical processes and their interactions with physical processes in the tropical Pacific.

关键词： Ocean chlorophyll Bio-climate feedbacks Interannual variability Tropical instability waves Counteracting effects A hybrid coupled model

Unraveling the enigma:A comprehensive review of solid pseudopapillary tumor of the pancreas

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World Journal of Gastrointestinal Oncology 2024年第3期16卷 614-629页

作者： Ye-Cheng Xu De-Liang fu feng Yang Department of Pancreatic Surgery Pancreatic Disease InstituteHuashan HospitalFudan UniversityShanghai 200040China

Solid pseudopapillary tumor of the pancreas(SPTP)is a rare neoplasm predom-inantly observed in young ***,CTNNB1 mutations,β-catenin nuclear accumulation,and subsequent Wnt-signaling pathway activation are the leading molecular *** preoperative diagnosis often relies on imaging techniques and endoscopic *** resection remains the mainstay *** models,such as the fudan Prognostic Index,show promise as predictive tools for assessing the prognosis of *** three types of metachronous liver metastasis can be beneficial in tailoring individu-alized treatment and follow-up *** advancements,challenges persist in understanding its etiology,establishing standardized treatments for unresectable or metastatic diseases,and developing a widely recognized grading *** comprehensive review aims to elucidate the enigma by consolidating current knowledge on the epidemiology,clinical presentation,pathology,molecular characteristics,diagnostic methods,treatment options,and prognostic factors.

关键词： Pancreas Solid pseudopapillary tumor β-catenin Endoscopic ultrasound Surgery Recurrence Liver metastasis Prognostic prediction

Enhancing Dense Small Object Detection in UAV Images Based on Hybrid Transformer

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Computers, Materials & Continua 2024年第3期78卷 3993-4013页

作者： Changfeng feng Chunping Wang Dongdong Zhang Renke Kou Qiang fu shijiazhuang Campus People Liberation Army Engineering UniversityShijiazhuang050003China School of Information and Intelligent Engineering Sanya UniversitySanya572000China

Transformer-based models have facilitated significant advances in object ***,their extensive computational consumption and suboptimal detection of dense small objects curtail their applicability in unmanned aerial vehicle(UAV)*** these limitations,we propose a hybrid transformer-based detector,H-DETR,and enhance it for dense small objects,leading to an accurate and efficient ***,we introduce a hybrid transformer encoder,which integrates a convolutional neural network-based cross-scale fusion module with the original encoder to handle multi-scale feature sequences more ***,we propose two novel strategies to enhance detection performance without incurring additional inference *** filter is designed to cope with the dense clustering inherent in drone-captured images by counteracting similar queries with a training-aware non-maximum *** denoising learning is a novel enhancement method inspired by adversarial learning,which improves the detection of numerous small targets by counteracting the effects of artificial spatial and semantic *** experiments on the VisDrone and UAVDT datasets substantiate the effectiveness of our approach,achieving a significant improvement in accuracy with a reduction in computational *** method achieves 31.9%and 21.1%AP on the VisDrone and UAVDT datasets,respectively,and has a faster inference speed,making it a competitive model in UAV image object detection.

关键词： UAV images transformer dense small object detection

Controlling of coordination state of Ru_(x)N_(y) clusters for efficient oxygen reduction electrocatalysis

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Nano Research 2024年第3期17卷 1035-1041页

作者： Weiyang fu Yihuan Yu Tongtong Liu Yinliang Cao Zhengping Zhang feng Wang State Key Laboratory of Chemical Resource Engineering Beijing Key Laboratory of Electrochemical Process and Technology for MaterialsBeijing University of Chemical TechnologyBeijing 100029China Beijing Advanced Innovation Center for Soft Matter Science and Engineering Beijing University of Chemical TechnologyBeijing 100029China Zhejiang Tianneng Hydrogen Energy Technology Co. Ltd.Huzhou 313100China

Ruthenium(Ru)is an attractive potential alternative to platinum as an electrocatalyst for the oxygen reduction reaction(ORR),in virtue of its high catalytic selectivity and relatively low *** this work,a series of well-dispersed nitrogen-coordinated Ru-clusters on carbon black(Ru_(x)N_(y)/C)were prepared by pyrolyzing different Ru-containing sandwich compounds as the Ru *** higher thermal stability of these complexed sandwich precursors(bis(1,2,3,4,5-pentamethylcyclopentadienyl)Ru(II)monomer,dichloro(p-cymene)Ru(II)dimer,and chloro(1,2,3,4,5-pentamethylcyclopentadienyl)Ru(II)tetramer)affords the control of coordinated state for the resulting Ru-clusters,in comparison of that derived from ruthenium *** the pyrolysis treatment,the Ru coordinated state in Ru_(x)N_(y)/C,with the Ru–N and Ru–Ru bonds,still showed the structural inheritance from the Ru(II)monomer,dimer,and tetramer,but using ruthenium chlorides as the Ru source resulted in the nanoscale Ru *** ORR testing exhibited that the Ru_(x)N_(y)/C sample derived from the Ru(II)tetramer(Ru_(x)N_(y)/C-T)presents the higher catalytic activity than the other obtained samples in either alkaline or acidic *** in the acidic electrolyte,Ru_(x)N_(y)/C-T shows the comparable ORR activity to that of Pt/C catalysts,and it shows the superior tolerance against methanol and *** X-ray absorption spectroscopy and density functional theory calculations demonstrate that these tetra-nuclear Ru-clusters could be the most active site due to their broadened d-orbital bands and lower energy d-band center than those of other subnano species and nanocrystals,and their favorable Yeager-type adsorption of O_(2)-molecules is also contributed to promoting O–O bond cleavage and accelerating the ORR process.

关键词： ruthenium clusters coordination environment sandwich compounds electrocatalysis oxygen reduction reaction

Achieving high-efficient photocatalytic persulfate-activated degradation of tetracycline via carbon dots modified MIL-101(Fe)octahedrons

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Chinese Journal of Chemical Engineering 2024年第2期66卷 298-309页

作者： Hao Yuan Xinhai Sun Shuai Zhang Weilong shi feng Guo School of Material Science and Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China School of Energy and Power Jiangsu University of Science and TechnologyZhenjiang 212003China

The synergistic reaction of photocatalysis and advanced oxidation is a valid strategy for the degradation of harmful antibiotic ***,carbon dots(CDs)modified MIL-101(Fe)octahedrons to form CDs/MIL-101(Fe)composite photocatalyst was synthesized for visible light-driven photocatalytic/persulfate(PS)-activated tetracycline(TC)*** electron spin resonance(ESR)spectra,scavenging experiment and electrochemical analysis were carried out to reveal that the high visible light-driven photocatalytic degradation activity of TC over CDs/MIL-101(Fe)photocatalysts is not only ascribed to the production of free active radicals in the CDs/MIL-101(Fe)/PS system(·OH,·SO_(4-),^(1)O_(2),h^(+)and·O_(2)^(-))but also attributed to the consumption of electrons caused by the PS,which can suppress the recombination of photo-generated carriers as well as strong light scattering and electron trapping effects of ***,the possible degradation pathways were proposed by analyzing intermediates via liquid chromatography-mass spectrometry *** research presents a rational design conception to construct a CDs/PS-based photocatalysis/advanced oxidation technology with high-efficient degradation activity for the remediation of organic antibiotic pollutant wastewater and for the improvement of carrier transport kinetics of photocatalysts.

关键词： Carbon dots MIL-101(Fe) Photocatalytic Persulfate activation Tetracycline degradation

Reducing Subspaces of Toeplitz Operators Induced by a Class of Non-analytic Monomials over the Unit Ball

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Acta Mathematica Sinica,English Series 2024年第7期40卷 1767-1777页

作者： Yan Yue shi Bo ZHANG Xu TANG Yu feng LU School of Mathematical Sciences Ocean University of ChinaQingdao 266100P.R.China School of Mathematics and Information Sciences Yantai UniversityYantai 264005P.R.China School of Mathematical Sciences Space Engineering UniversityBeijing 101416P.R.China School of Mathematical Sciences Dalian University of TechnologyDalian 116024P.R.China

In this paper,we describe the minimal reducing subspaces of Toeplitz operators induced by non-analytic monomials on the weighted Bergman spaces and Dirichlet spaces over the unit ball B_(2).It is proved that each minimal reducing subspace M is finite dimensional,and if dim M≥3,then M is induced by a ***,the structure of commutant algebra v(T_(w)N_(z)N):={M^(*)_(w)NM_(z)N,M^(*)_(z)NM_(w)N}′is determined by N and the two dimensional minimal reducing subspaces of(T_(w)N_(z)*** also give some interesting examples.

关键词： Reducing subspace operator-weighted shifts Toeplitz operator von Neumann algebra

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An antistatic agent based on polyionic liquid applied to nylon 6

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Green Chemical Engineering 2024年第3期5卷 399-407页

作者： Shuangchan fu Yinghao Yu feng Wang Jing Li Zhiqi Cai School of Chemistry and Chemical Engineering South China University of TechnologyGuangzhou510641China SCUT-Zhuhai Institute of Modern Industrial Innovation Zhuhai519175China Yantai Xintelu New Material Technology Co.LTD. Shandong264006China

In order to improve the electrical conductivity of nylon 6(PA6)and avoid misfires and explosions caused by static charge accumulation,a quaternary ammonium salt polyionic liquid(PIL)antistatic agent was synthesized in this *** surface resistance of PA6 was reduced to 10~8Ωwith the addition of 2 wt%antistatic agent,and the mechanical properties and aging resistance of the substrate were ***,the morphology and crystallinity of PIL/PA6 composites were further characterized by scanning electron microscope(SEM),energy dispersion spectrometer(EDS)and X-ray diffraction(XRD).It is worth noting that the quaternary ammonium salt polyionic liquid antistatic agent synthesized in this paper has the advantages of excellent antistatic effect,durability,low cost,and simple reaction condition,so it has a broad application prospect in the antistatic aspect of PA6.

关键词： Polyionic liquid Nylon 6 Antistatic agent

An intelligent control method based on artificial neural network for numerical flight simulation of the basic finner projectile with pitching maneuver

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Defence Technology（防务技术） 2024年第2期32卷 663-674页

作者： Yiming Liang Guangning Li Min Xu Junmin Zhao feng Hao Hongbo shi Northwestern Polytechnical University School of Astronautics Xi’an 710072China China North Industries Group Corporation No 203 Research Institute Xi’an 710065China

In this paper,an intelligent control method applying on numerical virtual flight is *** proposed algorithm is verified and evaluated by combining with the case of the basic finner projectile model and shows a good application ***,a numerical virtual flight simulation model based on overlapping dynamic mesh technology is *** order to verify the accuracy of the dynamic grid technology and the calculation of unsteady flow,a numerical simulation of the basic finner projectile without control is carried *** simulation results are in good agreement with the experiment data which shows that the algorithm used in this paper can also be used in the design and evaluation of the intelligent controller in the numerical virtual flight ***,combined with the real-time control requirements of aerodynamic,attitude and displacement parameters of the projectile during the flight process,the numerical simulations of the basic finner projectile’s pitch channel are carried out under the traditional PID(Proportional-Integral-Derivative)control strategy and the intelligent PID control strategy *** intelligent PID controller based on BP(Back Propagation)neural network can realize online learning and self-optimization of control parameters according to the acquired real-time flight *** with the traditional PID controller,the concerned control variable overshoot,rise time,transition time and steady state error and other performance indicators have been greatly improved,and the higher the learning efficiency or the inertia coefficient,the faster the system,the larger the overshoot,and the smaller the stability *** intelligent control method applying on numerical virtual flight is capable of solving the complicated unsteady motion and flow with the intelligent PID control strategy and has a strong promotion to engineering application.

关键词： Numerical virtual flight Intelligent control BP neural network PID Moving chimera grid