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Irregularly sampled seismic data interpolation via wavelet-based convolutional block attention deep learning 被引量:2
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作者 Yihuai Lou Lukun Wu +4 位作者 Lin Liu Kai Yu Naihao Liu Zhiguo Wang Wei Wang 《Artificial Intelligence in Geosciences》 2022年第1期192-202,共11页
Seismic data interpolation,especially irregularly sampled data interpolation,is a critical task for seismic processing and subsequent interpretation.Recently,with the development of machine learning and deep learning,... Seismic data interpolation,especially irregularly sampled data interpolation,is a critical task for seismic processing and subsequent interpretation.Recently,with the development of machine learning and deep learning,convolutional neural networks(CNNs)are applied for interpolating irregularly sampled seismic data.CNN based approaches can address the apparent defects of traditional interpolation methods,such as the low computational efficiency and the difficulty on parameters selection.However,current CNN based methods only consider the temporal and spatial features of irregularly sampled seismic data,which fail to consider the frequency features of seismic data,i.e.,the multi-scale features.To overcome these drawbacks,we propose a wavelet-based convolutional block attention deep learning(W-CBADL)network for irregularly sampled seismic data reconstruction.We firstly introduce the discrete wavelet transform(DWT)and the inverse wavelet transform(IWT)to the commonly used U-Net by considering the multi-scale features of irregularly sampled seismic data.Moreover,we propose to adopt the convolutional block attention module(CBAM)to precisely restore sampled seismic traces,which could apply the attention to both channel and spatial dimensions.Finally,we adopt the proposed W-CBADL model to synthetic and pre-stack field data to evaluate its validity and effectiveness.The results demonstrate that the proposed W-CBADL model could reconstruct irregularly sampled seismic data more effectively and more efficiently than the state-of-the-art contrastive CNN based models. 展开更多
关键词 irregularly sampled seismic data reconstruction Deep learning U-Net Discrete wavelet transform Convolutional block attention module
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Irregularly red-cell antibody detection and subgroup typing of ABO,Rh systemsin donors of Shanghai-recently reports
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《中国输血杂志》 CAS CSCD 2001年第S1期363-,共1页
关键词 ABO RH irregularly red-cell antibody detection and subgroup typing of ABO Rh systemsin donors of Shanghai-recently reports cell
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Local differential quadrature method using irregularly distributed nodes for solving partial differential equations
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作者 王娟 夏利伟 马杭 《Journal of Shanghai University(English Edition)》 CAS 2008年第2期110-114,共5页
In the conventional differential quadrature (DQ) method the functional values along a mesh line are used to approximate derivatives and its application is limited to regular regions. In this paper, a local different... In the conventional differential quadrature (DQ) method the functional values along a mesh line are used to approximate derivatives and its application is limited to regular regions. In this paper, a local differential quadrature (LDQ) method was developed by using irregular distributed nodes, where any spatial derivative at a nodal point is approximated by a linear weighted sum of the functional values of nodes in the local physical domain. The weighting coefficients in the new approach are determined by the quadrature rule with the aid of nodal interpolation. Since the proposed method directly approximates the derivative, it can be consistently well applied to linear and nonlinear problems and the mesh-free feature is still kept. Numerical examples are provided to validate the LDQ method. 展开更多
关键词 differential quadrature (DQ) method irregular node distribution INTERPOLATION MESH-FREE partial differentialequation (PDE).
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Determination of the coefficient of rolling friction of an irregularly shaped maize particle group using physical experiment and simulations 被引量:23
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作者 Lijun Wang Rui Li +2 位作者 Baoxin Wu ZhenchaoWu Zhenjun Ding 《Particuology》 SCIE EI CAS CSCD 2018年第3期185-195,共11页
The coefficient of rolling friction is an important physical property of a maize particle. It is difficult to obtain the value of this coefficient because of the irregular shape of maize particles. This paper describe... The coefficient of rolling friction is an important physical property of a maize particle. It is difficult to obtain the value of this coefficient because of the irregular shape of maize particles. This paper describes an approach that combines the discrete-element method (DEM) and a physical test to determine the coefficient of rolling friction of irregularly shaped maize particles. A novel test platform was used to obtain the maize particle's coefficient of restitution and the coefficient of static friction. EDEM software (DEM- Solutions, United Kingdom) was used to simulate the accumulation of maize particles on particles and on a zincified plate. The golden-section method was used to determine the range of the maize particle's coefficient of roiling friction. A single-factor test was used to determine the relationship between the maize particle's coefficient of rolling friction and their angle of repose. The results obtained from the EDEM simulation were compared with physical test results to determine the intergranular coefficient of rolling friction and the coefficient of roiling friction between maize particles and the zincified plate. Our study demonstrates that the angle of repose increases linearly with the coefficient of rolling friction of maize particles. The effect of the coefficient of rolling friction on the particle movement is studied. The physical verification test indicates that the obtained rolling friction of the maize particles is accurate. The findings of this paper provide a theoretical basis for maize-processing machine design and a discrete-element studv of the motion of maize particles inside such machines. 展开更多
关键词 Coefficient of rolling friction irregularly shaped particle ACCUMULATION Simulation Golden-section method Physical experiment
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IoT Empowered Early Warning of Transmission Line Galloping Based on Integrated Optical Fiber Sensing and Weather Forecast Time Series Data 被引量:1
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作者 Zhe Li Yun Liang +1 位作者 Jinyu Wang Yang Gao 《Computers, Materials & Continua》 SCIE EI 2025年第1期1171-1192,共22页
Iced transmission line galloping poses a significant threat to the safety and reliability of power systems,leading directly to line tripping,disconnections,and power outages.Existing early warning methods of iced tran... Iced transmission line galloping poses a significant threat to the safety and reliability of power systems,leading directly to line tripping,disconnections,and power outages.Existing early warning methods of iced transmission line galloping suffer from issues such as reliance on a single data source,neglect of irregular time series,and lack of attention-based closed-loop feedback,resulting in high rates of missed and false alarms.To address these challenges,we propose an Internet of Things(IoT)empowered early warning method of transmission line galloping that integrates time series data from optical fiber sensing and weather forecast.Initially,the method applies a primary adaptive weighted fusion to the IoT empowered optical fiber real-time sensing data and weather forecast data,followed by a secondary fusion based on a Back Propagation(BP)neural network,and uses the K-medoids algorithm for clustering the fused data.Furthermore,an adaptive irregular time series perception adjustment module is introduced into the traditional Gated Recurrent Unit(GRU)network,and closed-loop feedback based on attentionmechanism is employed to update network parameters through gradient feedback of the loss function,enabling closed-loop training and time series data prediction of the GRU network model.Subsequently,considering various types of prediction data and the duration of icing,an iced transmission line galloping risk coefficient is established,and warnings are categorized based on this coefficient.Finally,using an IoT-driven realistic dataset of iced transmission line galloping,the effectiveness of the proposed method is validated through multi-dimensional simulation scenarios. 展开更多
关键词 Optical fiber sensing multi-source data fusion early warning of galloping time series data IOT adaptive weighted learning irregular time series perception closed-loop attention mechanism
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Determination of the coefficient of rolling friction of irregularly shaped maize particles by using discrete element method 被引量:7
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作者 Linrong Shi Wuyun Zhao +1 位作者 Bugong Sun Wei Sun 《International Journal of Agricultural and Biological Engineering》 SCIE EI CAS 2020年第2期15-25,共11页
The coefficient of rolling friction is a foundation parameter for conducting particles simulation,however,which of irregularly shaped maize seeds is difficult to measure.Furthermore,the coefficient of rolling friction... The coefficient of rolling friction is a foundation parameter for conducting particles simulation,however,which of irregularly shaped maize seeds is difficult to measure.Furthermore,the coefficient of rolling friction between the simulation particles and the actual seeds is inconsistent due to the shaped difference of model and different position of gravity center.This paper use two methods to determinate the coefficient of rolling friction based on discrete element method(DEM)and physical experiments.Three types of maize models from five different shaped maize samples(including horse-tooth shape,spherical cone shape,spherical shape,oblate shape,irregular shape)were developed with the help of slice modeling and 3D modeling technology.Aluminum cylinder container is used to arrange the simulation experiments of angle of repose with taking the coefficient of rolling friction as independent variables and the simulation angle of repose as target values.After predicting detailed the coefficient of rolling friction(including horse-tooth shape,spherical cone shape,spherical shape,between horse-tooth shape and spherical cone shape,between horse-tooth shape and spherical shape,between spherical shape and spherical cone shape maize models),and forecasting a unified the coefficient of rolling friction among horse-tooth shape,spherical cone shape and spherical shape maize models,two types of materials(aluminum cylinder container and organic glass container)were used to validate the difference the angle of repose between the simulation maize models and actual maize seeds.Results show the relative error of the angle of repose between the maize models controlled by the coefficient of rolling friction through the detailed method and the actual maize seeds is 0.22%,0.33%in aluminum cylinder,organic glass container,respectively.The relative error of the angle of repose between the simulation maize models controlled by the coefficient of rolling friction through the united method and actual maize seeds is 2.47%,2.97%in aluminum cylinder,organic glass container,respectively.Although the difference of the angle of repose between two method is smaller,the detailed method is better.Moreover,From the accumulation process of the angle of repose we found that the difference on the contacts number between maize models and bottom plate,the change curve of the rotational kinetic energy,the potential energy of maize models controlled by the coefficient of rolling friction through the detailed and the united method are evidently.We can choose a better method to predict the coefficient of rolling friction of maize seeds according to the application situation and investigation objective of irregular maize seeds.The results can provide a theoretical basis for designing and optimizing the structure of the seed-metering machine with DEM. 展开更多
关键词 coefficient of rolling friction MAIZE irregularly shaped model angle of repose discrete element method
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Crystallization Modulation and Holistic Passivation Enables Efficient Two‑Terminal Perovskite/CuIn(Ga)Se_(2)Tandem Solar Cells
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作者 Cong Geng Kuanxiang Zhang +7 位作者 Changhua Wang Chung Hsien Wu Jiwen Jiang Fei Long Liyuan Han Qifeng Han Yi‑Bing Cheng Yong Peng 《Nano-Micro Letters》 SCIE EI CAS 2025年第1期205-215,共11页
Two-terminal(2-T)perovskite(PVK)/CuIn(Ga)Se_(2)(CIGS)tandem solar cells(TSCs)have been considered as an ideal tandem cell because of their best bandgap matching regarding to Shockley–Queisser(S–Q)limits.However,the ... Two-terminal(2-T)perovskite(PVK)/CuIn(Ga)Se_(2)(CIGS)tandem solar cells(TSCs)have been considered as an ideal tandem cell because of their best bandgap matching regarding to Shockley–Queisser(S–Q)limits.However,the nature of the irregular rough morphology of commercial CIGS prevents people from improving tandem device performances.In this paper,D-homoserine lactone hydrochloride is proven to improve coverage of PVK materials on irregular rough CIGS surfaces and also passivate bulk defects by modulating the growth of PVK crystals.In addition,the minority carriers near the PVK/C60 interface and the incompletely passivated trap states caused interface recombination.A surface reconstruction with 2-thiopheneethylammonium iodide and N,N-dimethylformamide assisted passivates the defect sites located at the surface and grain boundaries.Meanwhile,LiF is used to create this field effect,repelling hole carriers away from the PVK and C60 interface and thus reducing recombination.As a result,a 2-T PVK/CIGS tandem yielded a power conversion efficiency of 24.6%(0.16 cm^(2)),one of the highest results for 2-T PVK/CIGS TSCs to our knowledge.This validation underscores the potential of our methodology in achieving superior performance in PVK/CIGS tandem solar cells. 展开更多
关键词 PVK/CIGS TSCs Irregular rough surfaces Modulating the growth PVK/C60 interface recombination
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A Novel Model for Describing Rail Weld Irregularities and Predicting Wheel-Rail Forces Using a Machine Learning Approach
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作者 Linlin Sun Zihui Wang +3 位作者 Shukun Cui Ziquan Yan Weiping Hu Qingchun Meng 《Computer Modeling in Engineering & Sciences》 SCIE EI 2025年第1期555-577,共23页
Rail weld irregularities are one of the primary excitation sources for vehicle-track interaction dynamics in modern high-speed railways.They can cause significant wheel-rail dynamic interactions,leading to wheel-rail ... Rail weld irregularities are one of the primary excitation sources for vehicle-track interaction dynamics in modern high-speed railways.They can cause significant wheel-rail dynamic interactions,leading to wheel-rail noise,component damage,and deterioration.Few researchers have employed the vehicle-track interaction dynamic model to study the dynamic interactions between wheel and rail induced by rail weld geometry irregularities.However,the cosine wave model used to simulate rail weld irregularities mainly focuses on the maximum value and neglects the geometric shape.In this study,novel theoretical models were developed for three categories of rail weld irregularities,based on measurements of the high-speed railway from Beijing to Shanghai.The vertical dynamic forces in the time and frequency domains were compared under different running speeds.These forces generated by the rail weld irregularities that were measured and modeled,respectively,were compared to validate the accuracy of the proposed model.Finally,based on the numerical study,the impact force due to rail weld irrregularity is modeled using an Artificial Neural Network(ANN),and the optimum combination of parameters for this model is found.The results showed that the proposed model provided a more accurate wheel/rail dynamic evaluation caused by rail weld irregularities than that established in the literature.The ANN model used in this paper can effectively predict the impact force due to rail weld irrregularity while reducing the computation time. 展开更多
关键词 Rail weld irregularity high-speed railway vehicle-track coupled dynamics wheel/rail dynamic vertical force artificial neural networks
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Dynamic modeling and simulation of irregular faults in axle box bearings of high-speed trains
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作者 Xiaohui GU Yajia WANG +2 位作者 Pengfei LIU Zechao LIU Shaopu YANG 《Applied Mathematics and Mechanics(English Edition)》 2025年第10期1883-1902,共20页
Axle box bearings are critical components of high-speed trains.Localized defects,such as pitting and spalling,on raceways or rollers pose significant threats to the operational safety of railway vehicles.In this work,... Axle box bearings are critical components of high-speed trains.Localized defects,such as pitting and spalling,on raceways or rollers pose significant threats to the operational safety of railway vehicles.In this work,a novel bearing-flexible axle boxvehicle coupling model is established to explore the vibration characteristics of axle box bearings with irregular localized defects.First,based on the contact and kinematic relationship between rollers and raceways,the three-dimensional(3D)bearing force elements are analyzed and formulated.Second,the established model and a flexible axle box are integrated into the vehicle,and the responses of the normal and faulty bearings under the combined excitations of wheel roughness and track irregularities are simulated.Third,the simulation results are verified through a rolling-vibrating test bench for full-scale wheelsets of high-speed trains.The comparisons of the fault-induced repetitive transients in the time-domain and the fault characteristic frequencies in the envelope spectra demonstrate the efficiency of the proposed model.Finally,based on the flexible axle box model,a sensitivity analysis of the accelerometer placements to the bearing faults is carried out,and the optimal one is identified based on both the time-domain and frequency-domain signal-to-noise ratios(SNRs)for engineering applications. 展开更多
关键词 axle box bearing irregular fault track irregularity flexible axle box accelerometer placement selection
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A statistical survey of polar cap cold and hot patches in the Southern Hemisphere using a DMSP Satellite
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作者 Duan Zhang QingHe Zhang +11 位作者 Kjellmar Oksavik ZanYang Xing LRLyons HuiGen Yang Tong Xu Marc Hairston XiangYu Wang YuZhang Ma GuoJun Li Yong Wang Sheng Lu Jin Wang 《Earth and Planetary Physics》 2025年第4期955-965,共11页
This paper is a statistical survey of Southern Hemisphere cold and hot polar cap patches,in relation to the interplanetary magnetic field(IMF)and ionospheric convection geometry.A total of 11,946 patch events were ide... This paper is a statistical survey of Southern Hemisphere cold and hot polar cap patches,in relation to the interplanetary magnetic field(IMF)and ionospheric convection geometry.A total of 11,946 patch events were identified by Defense Meteorological Satellite Program(DMSP)F16 during the years 2011 to 2022.A temperature ratio of ion/electron temperature(T_(i)/T_(e))<0.68 is recommended to define a hot patch in the Southern Hemisphere,otherwise it is defined as a cold patch.The cold and hot patches have different dependencies on IMF clock angle,while their dependencies on IMF cone angle are similar.Both cold and hot patches appear most often on the duskside,and the distribution of cold patches gradually decreases from the dayside to the nightside,while hot patches have a higher occurrence rate near 14 and 21 magnetic local time(MLT).Moreover,we compared the key plasma characteristics of polar cap cold and hot patches in the Southern and Northern Hemispheres.The intensity of the duskside upward field-aligned current of patches in the Southern Hemisphere(SH)is stronger than that in the Northern Hemisphere(SH),which may be due to the discrepancy in conductivities between the two hemispheres,caused by the tilted dipole.In both hemispheres,the downward soft-electron energy flux of the dawnside patches is significantly greater than that of the duskside patches. 展开更多
关键词 polar ionosphere polar cap patch IRREGULARITIES statistical survey southern hemisphere.
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Carbody sway behaviour of railway vehicles due to track irregularity from rail alternate side wear
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作者 Lai Wei Jing Zeng +3 位作者 Ren Luo Feng Gan Jijun Gong Jun Jiang 《Railway Engineering Science》 2025年第1期27-42,共16页
Track irregularity from rail alternate side wear is manifested as uneven rail wear waveforms alternating in the left and right rails with equal intervals,which will cause carbody sway behaviour of railway vehicles and... Track irregularity from rail alternate side wear is manifested as uneven rail wear waveforms alternating in the left and right rails with equal intervals,which will cause carbody sway behaviour of railway vehicles and greatly influences the passenger comfort.In this work,the carbody sway behaviour and mechanism due to track irregularity from rail alternate side wear and possible solutions to this issue were studied by the field testing and numerical calculation approaches.First,the carbody sway of an urban rail transit train is introduced with full-scale field tests,through which the rail alternate side wear is characterized and the formatted track irregularity are presented.Then,multibody vehicle dynamic models are developed to reproduce the carbody sway behaviour induced by the track irregularity from the rail alternate side wear.The creep forces acting on the wheel and rail are preliminarily discussed to study the influence of the carbody sway on the wear of the wheel flange and the rail corner.Finally,some potential solutions,e.g.improving the damping ratio of carbody rigid mode and rail grinding,are proposed to relieve this issue.It is concluded that an increased damping ratio of the carbody mode can alleviate the carbody sway and wheel–rail interactions,while properly maintaining track conditions can improve the vehicle performance. 展开更多
关键词 Carbody sway Track irregularity Rail wear Creep force Carbody mode
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Large-scale experimental study on scour around both slender and large monopiles under irregular waves
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作者 En-yu Gong Song-gui Chen +2 位作者 Xin Chen Da-wei Guan Jin-hai Zheng 《Water Science and Engineering》 2025年第3期369-377,共9页
Offshore wind power plays a crucial role in energy strategies.The results of traditional small-scale physical models may be unreliable when extrapolated to large field scales.This study addressed this limitation by co... Offshore wind power plays a crucial role in energy strategies.The results of traditional small-scale physical models may be unreliable when extrapolated to large field scales.This study addressed this limitation by conducting large-scale(1:13)experiments to investigate the scour hole pattern and equilibrium scour depth around both slender and large monopiles under irregular waves.The experiments adopted KeuleganeCarpenter number(NKC)values from 1.01 to 8.89 and diffraction parameter(D/L,where D is the diameter of the monopile,and L is the wave length)values from 0.016 to 0.056.The results showed that changes in the maximum scour location and scour hole shape around a slender monopile were associated with NKC,with differences observed between irregular and regular waves.Improving the calculation of NKC enhanced the accuracy of existing scour formulae under irregular waves.The maximum scour locations around a large monopile were consistently found on both sides,regardless of NKC and D/L,but the scour hole topography was influenced by both parameters.Notably,the scour range around a large monopile was at least as large as the monopile diameter. 展开更多
关键词 SCOUR KeuleganeCarpenter number Irregular waves Equilibrium scour depth Large-scale test
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Multi-instrumental observations of nighttime X-pattern of equatorial ionization anomaly during magnetically quiet time: case study
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作者 XinYi Rang Chao Xiong +6 位作者 YuHao Zheng Jing Liu Yu Jiao ShunZu Gao YuYang Huang Xin Wan Fan Yin 《Earth and Planetary Physics》 2025年第2期410-423,共14页
In this study, we provide a detailed case study of the X-pattern of equatorial ionization anomaly(EIA) observed on the night of September 12, 2021 by the Global-scale Observations of the Limb and Disk(GOLD) mission. U... In this study, we provide a detailed case study of the X-pattern of equatorial ionization anomaly(EIA) observed on the night of September 12, 2021 by the Global-scale Observations of the Limb and Disk(GOLD) mission. Unlike most previous studies about the X-pattern observed under the severely disturbed background ionosphere, this event is observed under geomagnetically quiet and low solar activity conditions. GOLD's continuous observations reveal that the X-pattern intensity evolves with local time, while its center's longitude remains constant. The total electron content(TEC) data derived from the ground-based Global Navigation Satellite System(GNSS) network aligns well with GOLD observations in capturing the formation of the X-pattern, extending coverage to areas beyond GOLD's observational reach. Additionally, the ESA's Swarm mission show that both sides of the X-pattern can coincide with the occurrence of small-scale equatorial plasma bubbles(EPBs). To further analyze the possible drivers of the X-pattern, observations from the Ionospheric Connection Explorer(ICON) satellite were used. It shows that the latitudinal expansion(or width) between the EIA crests in two hemispheres is proportional(or inversely proportional) to the upward(or downward) plasma drift velocity, which suggests that the zonal electric field should have a notable influence on the formation of EIA X-pattern. Further simulations using the SAMI2 model support this mechanism, as the X-pattern of EIA is successfully reproduced by setting the vertical plasma drift to different values at different longitudes. 展开更多
关键词 nighttime ionosphere equatorial ionization anomaly X-pattern GOLD mission plasma irregularities
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Comprehensive Evaluation of Biomechanical and Biological Properties of the Porous Irregular Scaffolds Based on Voronoi-tessellation
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作者 Yuzhu Wang Chenhao Ma +3 位作者 Yufeng Wu Dawei Gao Yue Meng Haibin Wang 《Journal of Bionic Engineering》 2025年第1期322-340,共19页
The irregular porous structure,similar to human bone tissue,is more beneficial for bone ingrowth than the regular one.We proposed a new design method to create uniform and gradient irregular porous structures with por... The irregular porous structure,similar to human bone tissue,is more beneficial for bone ingrowth than the regular one.We proposed a new design method to create uniform and gradient irregular porous structures with porosities from 38 to 83%based on Voronoi tessellation.The models were fabricated using selective laser sintering,and micro-CT was used to assess their morphological features.Mechanical and fluid flow properties were evaluated through experiments and computational fluid dynamics simulations.Micro-CT scans confirmed that 3D printing can produce high-quality irregular structures.The Graded Irregular(GI)structure showed clear advantages in mechanical properties by reducing stress shielding and improving hydrodynamic performance with higher fluid flow velocity and lower permeability compared to the Uniform Irregular(UI)structure.Additionally,in vitro cell experiments indicated that the GI structure was better than the UI structure in promoting osteogenic differentiation,while in vivo animal studies showed that the GI structure was superior in terms of the ratio of Bone Volume to Total Volume(BV/TV)and Trabecular Number(Tb.N).Thus,the GI structure has greater application potential in bone tissue engineering. 展开更多
关键词 Irregular structure Mechanical properties Fluid dynamic Bone growth
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A Dark Energy Hypothesis V
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作者 James Togeas 《Journal of High Energy Physics, Gravitation and Cosmology》 2025年第1期56-60,共5页
The subject is the mass of the three dominant, equilibrium cosmological objects: the irregular galaxy (dwarf), the regular galaxy (Hubble’s “tuning fork”), and the galactic cluster. The standard ΛCDM theory and a ... The subject is the mass of the three dominant, equilibrium cosmological objects: the irregular galaxy (dwarf), the regular galaxy (Hubble’s “tuning fork”), and the galactic cluster. The standard ΛCDM theory and a DEH offer contrasting views on the origin of these masses. The latter suggests that they are relics of the early universe. 展开更多
关键词 Cosmic Structure IRREGULAR Regular Galaxies Galactic Clusters
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CardioMix:a multimodal image-based classification pipeline for enhanced ECG diagnosis
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作者 Kira Sam Shah Nawaz Raja Vavekanand 《Medical Data Mining》 2025年第1期50-55,共6页
Background:Irregular heartbeats can have serious health implications if left undetected and untreated for an extended period of time.Methods:This study leverages machine learning(ML)techniques to classify electrocardi... Background:Irregular heartbeats can have serious health implications if left undetected and untreated for an extended period of time.Methods:This study leverages machine learning(ML)techniques to classify electrocardiogram(ECG)heartbeats,comparing traditional feature-based ML methods with innovative image-based approaches.The dataset underwent rigorous preprocessing,including down-sampling,frequency filtering,beat segmentation,and normalization.Two methodologies were explored:(1)handcrafted feature extraction,utilizing metrics like heart rate variability and RR distances with LightGBM classifiers,and(2)image transformation of ECG signals using Gramian Angular Field(GAF),Markov Transition Field(MTF),and Recurrence Plot(RP),enabling multimodal input for convolutional neural networks(CNNs).The Synthetic Minority Oversampling Technique(SMOTE)addressed data imbalance,significantly improving minority-class metrics.Results:The handcrafted feature approach achieved notable performance,with LightGBM excelling in precision and recall.Image-based classification further enhanced outcomes,with a custom Inception-based CNN,attaining an 85%F1 score and 97%accuracy using combined GAF,MTF,and RP transformations.Statistical analyses confirmed the significance of these improvements.Conclusion:This work highlights the potential of ML for cardiac irregularities detection,demonstrating that combining advanced preprocessing,feature engineering,and state-of-the-art neural networks can improve classification accuracy.These findings contribute to advancing AI-driven diagnostic tools,offering promising implications for cardiovascular healthcare. 展开更多
关键词 irregular heartbeats ECG signals MULTIMODAL image-based classifications
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Verification and validation of a numerical wave tank with momentum source wave generation
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作者 Housheng Zhang Yijing Hu +1 位作者 Biao Huang Xin Zhao 《Acta Mechanica Sinica》 2025年第3期23-38,共16页
systematic verification and validation(V&V)of our previously proposed momentum source wave generation method is performed.Some settings of previous numerical wave tanks(NWTs)of regular and irregular waves have bee... systematic verification and validation(V&V)of our previously proposed momentum source wave generation method is performed.Some settings of previous numerical wave tanks(NWTs)of regular and irregular waves have been optimized.The H2-5 V&V method involving five mesh sizes with mesh refinement ratio being 1.225 is used to verify the NWT of regular waves,in which the wave height and mass conservation are mainly considered based on a Lv3(H s=0.75 m)and a Lv6(H s=5 m)regular wave.Additionally,eight different sea states are chosen to validate the wave height,mass conservation and wave frequency of regular waves.Regarding the NWT of irregular waves,five different sea states with significant wave heights ranging from 0.09 m to 12.5 m are selected to validate the statistical characteristics of irregular waves,including the profile of the wave spectrum,peak frequency and significant wave height.Results show that the verification errors for Lv3 and Lv6 regular wave on the most refined grid are−0.018 and−0.35 for wave height,respectively,and−0.14 and for−0.17 mass conservation,respectively.The uncertainty estimation analysis shows that the numerical error could be partially balanced out by the modelling error to achieve a smaller validation error by adjusting the mesh size elaborately.And the validation errors of the wave height,mass conservation and dominant frequency of regular waves under different sea states are no more than 7%,8% and 2%,respectively.For a Lv3(H_(s)=0.75 m)and a Lv6(H_(s)=5 m)regular wave,simulations are validated on the wave height in wave development section for safety factors FS≈1 and FS≈0.5-1,respectively.Regarding irregular waves,the validation errors of the significant wave height and peak frequency are both lower than 2%. 展开更多
关键词 Verification and validation Wave generation Momentum source function Regular wave Irregular wave Uncertainty estimation
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Deep learning approach for morphology classification and particle sizing of industrial methanol-to-olefins(MTO)catalyst
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作者 Qingyu Wang Duiping Liu +3 位作者 Yong Lu Jibin Zhou Xiangang Ma Mao Ye 《Chinese Journal of Chemical Engineering》 2025年第8期1-10,共10页
Accurately acquiring catalyst size and morphology is essential for supporting catalytic reaction process design and optimal control. We report an intelligent catalyst sizing and morphological classification method bas... Accurately acquiring catalyst size and morphology is essential for supporting catalytic reaction process design and optimal control. We report an intelligent catalyst sizing and morphological classification method based on the Mask-RCNN framework. A dataset of 9880 high-resolution images was captured by using a self-made fiber-optic endoscopic system for 13 kinds of silicoaluminophosphate-34 (SAPO-34) catalyst samples with different coke. Then there were approximately 877881 individual particles extracted from this dataset by our AI-based particle recognition algorithm. To clearly describe the morphology of irregular particles, we proposed a hybrid classification criterion that combines five different parameters, which are deformity, circularity, roundness, aspect ratio, and compactness. Therefore, catalyst morphology can be classified into two categories with four types. The first category includes regular types, such as the spherical, ellipsoidal, and rod-shaped types. And all the irregular types fall into the second category. The experimental results showed that a catalyst particle tends to be larger when its coke deposition increased. Whereas particle morphology remained primarily spherical and ellipsoidal, the ratio of each type varied slightly according to its coke. Our findings illustrate that this is a promising approach to be developing intelligent instruments for catalyst particle sizing and classification. 展开更多
关键词 CATALYST Particle morphology Neural networks Particle size distribution Irregular particles
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Research on Optimization Method for Irregular Seismic Acquisition in Curved Wave Domain Based on Simulated Annealing
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作者 Zhao Hu Chen Meng-yang +4 位作者 Ni Yu-dong Zhao Rong-rong Jiang Fu-hao Chen Wei Dai Jing-yun 《Applied Geophysics》 2025年第1期220-230,236,共12页
With the continued expansion of oil and gas exploration,both in the eastern and western regions,the quality of seismic acquisition has become a key factor in oil and gas exploration in complex areas.However,convention... With the continued expansion of oil and gas exploration,both in the eastern and western regions,the quality of seismic acquisition has become a key factor in oil and gas exploration in complex areas.However,conventional seismic acquisition methods cannot efficiently avoid challenging acquisition locations and produce high-quality seismic data.In this regard,based on the curvelet transform,this paper proposes an irregular seismic acquisition method,which utilizes the high-precision characteristics of the curvelet transform and simulated annealing algorithm to establish a method for the evaluation of the coherence of irregular sampling matrices and design of observation systems.The method was verified using forward simulation and actual acquisition data.The results suggest the superior quality of seismic data gathered in complicated areas through this method over those acquired using traditional methods,which can provide technical guidance for the design of observation systems in complex areas. 展开更多
关键词 Seismic acquisition curvelet transform irregular acquisition design of observation system
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An Improved Local RBF Collocation Method for 3D Excavation Deformation Based on Direct Method and Mapping Technique
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作者 Cheng Deng Hui Zheng +2 位作者 Liangyong Gong Rongping Zhang Mengqi Wang 《Computer Modeling in Engineering & Sciences》 2025年第2期2147-2172,共26页
Since the plasticity of soil and the irregular shape of the excavation,the efficiency and stability of the traditional local radial basis function(RBF)collocation method(LRBFCM)are inadequate for analyzing three-dimen... Since the plasticity of soil and the irregular shape of the excavation,the efficiency and stability of the traditional local radial basis function(RBF)collocation method(LRBFCM)are inadequate for analyzing three-dimensional(3D)deformation of deep excavation.In this work,the technique known as the direct method,where the local influence nodes are collocated on a straight line,is introduced to optimize the LRBFCM.The direct method can improve the accuracy of the partial derivative,reduce the size effect caused by the large length-width ratio,and weaken the influence of the shape parameters on the LRBFCM.The mapping technique is adopted to transform the physical coordinates of a quadratic-type block to normalized coordinates,in which the deformation problem can easily be solved using the direct method.The stability of the LRBFCM is further modified by considering the irregular shape of 3D excavation,which is divided into several quadratic-type blocks.The soil’s plasticity is described by the Drucker-Prager(D-P)model.The improved LRBFCM is integrated with the incremental method to analyze the plasticity.Five different examples,including strip excavations and circular excavations,are presented to validate the proposed approach’s efficiency. 展开更多
关键词 Radial basis function collocation method irregular shape EXCAVATION elastic-plasticity
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