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Automated identification of steel weld defects,a convolutional neural network improved machine learning approach

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Frontiers of Structural and Civil Engineering 2024年第2期18卷 294-308页

作者： Zhan shu Ao WU Yuning SI Hanlin DONG Dejiang WANG Yifan li School of Mechanics and Engineering Science Shanghai UniversityShanghai 200444China School of Civil Engineering Shanghai Normal UniversityShanghai 201418China Shanghai PinlanData Technology Co. Ltd.Shanghai 200072China

This paper proposes a machine-learning-based methodology to automatically classify different types of steel weld defects,including lack of the fusion,porosity,slag inclusion,and the qualified(no defects)*** methodology solves the shortcomings of existing detection methods,such as expensive equipment,complicated operation and inability to detect internal *** study first collected percussed data from welded steel members with or without weld ***,three methods,the Mel frequency cepstral coefficients,short-time Fourier transform(STFT),and continuous wavelet transform were implemented and compared to explore the most appropriate features for classification of weld *** and convolutional neural network-enhanced algorithms were used to classify,the extracted ***,experiments were designed and performed to validate the proposed *** showed that STFT achieved higher accuracies(up to 96.63%on average)in the weld status *** convolutional neural network-enhanced support vector machine(SVM)outperformed six other algorithms with an average accuracy of 95.8%.In addition,random forest and SVM were efficient approaches with a balanced trade-off between the accuracies and the computational efforts.

关键词： steel weld machine learning convolutional neural network weld defect detection classification task percussion

Digital pathology-based artificial intelligence models for differential diagnosis and prognosis of sporadic odontogenic keratocysts

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International Journal of Oral Science 2024年第2期16卷 349-358页

作者： Xinjia cai Heyu Zhang Yanjin Wang Jianyun Zhang Tiejun li Department of Oral Pathology Peking University School and Hospital of Stomatology&National Center of Stomatology&National Clinical Research Center for Oral Diseases&National Engineering Research Center of Oral Biomaterials and Digital Medical DevicesBeijingChina Central Laboratory Peking University School and Hospital of StomatologyBeijingChina Department of Oral Pathology Shanghai Stomatological Hospital&School of StomatologyFudan UniversityShanghaiChina Research Unit of Precision Pathologic Diagnosis in Tumors of the Oral and Maxillofacial Regions Chinese Academy of Medical Sciences(2019RU034)BeijingChina

Odontogenic keratocyst(OKC)is a common jaw cyst with a high recurrence *** combined with basal cell carcinoma as well as skeletal and other developmental abnormalities is thought to be associated with Gorlin ***,OKC needs to be differentiated from orthokeratinized odontogenic cyst and other jaw *** of the different prognosis,differential diagnosis of several cysts can contribute to clinical *** collected 519 cases,comprising a total of 2157 hematoxylin and eosinstained images,to develop digital pathology-based artificial intelligence(AI)models for the diagnosis and prognosis of *** Inception_v3 neural network was utilized to train and test models developed from patch-level ***,whole slide imagelevel AI models were developed by integrating deep learning-generated pathology features with several machine learning *** AI models showed great performance in the diagnosis(AUC=0.935,95%CI:0.898–0.973)and prognosis(AUC=0.840,95%CI:0.751–0.930)of *** advantages of multiple slides model for integrating of histopathological information are demonstrated through a comparison with the single slide ***,the study investigates the correlation between AI features generated by deep learning and pathological findings,highlighting the interpretative potential of AI models in the ***,we have developed the robust diagnostic and prognostic models for *** AI model that is based on digital pathology shows promise potential for applications in odontogenic diseases of the jaw.

关键词： diagnosis pathology prognosis

Numerical modeling of fracture propagation of supercritical CO_(2)compound fracturing

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第7期16卷 2607-2628页

作者： Hao Chen Yong Kang Wanchun Jin Changhai li Can cai School of Mechanical Engineering Southwest Petroleum UniversityChengdu610500China Laboratory of High-pressure Jet Theory and Application Technology Southwest Petroleum UniversityChengdu610500China Hubei Key Laboratory of Waterjet Theory and New Technology Wuhan UniversityWuhan430072China Sinopec International Petroleum Exploration and Production Corporation Beijing 100029China

The exploitation of shale gas is promising due to depletion of the conventional energy and intensification of the greenhouse *** this paper,we proposed a heat-fluid-solid coupling damage model of supercritical CO_(2)(SC-CO_(2))compound fracturing which is expected to be an efficient and environmentally friendly way to develop shale *** coupling model is solved by the finite element method,and the results are in good agreement with the analytical solutions and fracturing *** on this model,the fracture propagation characteristics at the two stages of compound fracturing are studied and the influence of pressurization rate,in situ stress,bedding angle,and other factors are *** results show that at the SC-CO_(2)fracturing stage,a lower pressurization rate is conducive to formation of the branches around main fractures,while a higher pressurization rate inhibits formation of the branches around main fractures and promotes formation of the main *** bedding and in situ stress play a dominant role in the fracture *** the in situ stress ratio(δ_(x)/δ_(y))is 1,the presence of bedding can reduce the initiation pressure and failure ***,it will cause the fracture to propagate along the bedding direction,reducing the fracture *** rocks without bedding,hydraulic fracturing has the lengthening and widening effects for SC-CO_(2)induced *** shale,fractures induced at the hydraulic fracturing stage are more likely to be dominated by in situ stresses and have a shorter reorientation ***,fracture branches propagating along the maximum principal stress direction may be generated around the main fractures induced by SC-CO_(2)at the hydraulic fracturing *** the branches converge with the main fractures,fracture zones are easily formed,and thus the fracture complexity and damage area can be significantly *** results are instructive for the design and application of SC

关键词： Compound fracturing Fracture propagation Finite element method Damage evolution

Diffusion of nanochannel-confined knot along a tensioned polymer

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Communications in Theoretical Physics 2024年第4期76卷 158-166页

作者： Guobing cai Yong li Yuyu Feng Zhouhui Deng Yanhui liu College of Physics Guizhou UniversityGuiyang 550025China Kechuang Industrial Development Company limited Guian New AreaGuiyang 550025China State Key Laboratory of Public Big Data Guizhou UniversityGuiyang 550025China

The knots frequently occur in biopolymer and their diffusion plays an active role in the gene *** this work,Langevin dynamics simulations were carried out to detect the diffusion behaviours of a knot along a tensioned polymer in different spatial *** polymer accommodating a knot was tethered to two macrospheres to block the unravelling of the *** a result,the curves for the diffusion coefficients of the knot with different bending stiffness as a function of the tension in different spatial constraints were *** the space without constraints or with weak constraints,the corresponding curves for the knot with relatively large bending stiffness exhibited two turnover *** the contrary,for the knot with relatively small bending stiffness,the diffusion coefficients were monotonically reduced with increasing ***,in a space with strong constraints,all the curves showed one turnover behaviour regardless of the bending *** turnover behaviours divided the curves into different regimes,and the dominant diffusion mechanisms in the regimes,namely,knot-region breathing,self-reptation,and internal friction,were clearly *** effective friction coefficientsξof the knots with 3_(1),4_(1),5_(1) and 5_(2) types as a function of the knot size N at a fixed tension were well fitted by the relationξ∝*** effective friction coefficients of the knots at relatively large tension f>3 sharply increased with the knot complexity,which is not dependent on the spatial *** contrast,the values of these coefficients at relatively small tension f≤3 were remarkably dependent on the spatial *** work not only provides valuable simulation results to assist the understanding of the diffusion of DNA knot,but also highlights the single-molecule design for the manipulation of DNA knots in future.

关键词： knot langevin dynamics simulations diffusion coefficient self-reptation knot-region breathing internal friction

Printable,flexible ceramic fiber paper based on electrospinning

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Rare Metals 2024年第6期43卷 2739-2746页

作者： Yong-shuai Xie Yuan Cheng Yang Lyu Rui li Jie-cai Han National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Harbin Institute of TechnologyHarbin 150001China State Key Laboratory of Intelligent Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China

Based on the fact that it is challenging for the polymer flexible circuit substrates to meet the requirements of serving in high-temperature environments,this work proposed the idea of using printable ceramic fiber paper as a high-temperature flexible circuit substrate.A ceramic fiber paper with all ceramic components had been developed via electrospinning,solving the problems of low strength and severe strength drop at high temperatures of traditional ceramic fiber *** tensile strength of the prepared ceramic fiber paper is 2.63 MPa,and the reliable service temperature is 1200℃.Its bulk density is about 1.5 times that of traditional ceramic fiber *** can be printed with patterns by commercial inkjet printers like ordinary printing paper and has excellent *** feasibility of ceramic fiber paper as a flexible circuit substrate was verified by constructing a simple *** the fiber paper is significantly bent,the circuit still forms a complete path,which proves that it has a strong application potential for high-temperature flexible circuit substrate and is expected to promote the development of flexible electronic devices serving at extreme high-temperature environments.

关键词： Ceramic fiber paper High temperature Inkjet printing Flexible electronic

Sedimentary Environment and Mineralization of the Black Shale Polymetallic Layer in the Early Cambrian,SW China:Constraints from in situ LA-ICP-MS Analysis of Pyrite

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Acta Geologica Sinica(English Edition) 2024年第2期98卷 416-429页

作者： YANG Zhen FU Yong li Chao cai Xi GUO Chuan College of Eco-Environmental Engineering Guizhou Minzu UniversityGuiyang 550025China College of Resources and Environmental Engineering Guizhou UniversityGuiyang 550025China Key Laboratory of Karst Georesources and the Environment Ministry of EducationGuizhou UniversityGuiyang 500025China National Research Center for Geoanalysis Chinese Academy of Geological SciencesBeijing 100037China

A polymetallic layer is usually developed at the bottom of the early Cambrian black shale in Guizhou *** mineral that makes up the polymetallic layer is related to the sedimentary *** analyze the differentiation mechanism between polymetallic deposits(Ni-Mo and V),the Zhijin Gezhongwu profile located in the outer shelf and the Sansui Haishan V deposit located in the lower slope are selected to study the in situ sulfur isotopes and trace elements of *** results show that δ^(34)S values of pyrite vary widely from−7.8‰to 28‰in the Gezhongwu profile,while the δ^(34)S values are relatively uniform(from 27.8‰to 38.4‰)in the Haishan *** isotopic S composition is consistent with the transition that occurs in the sedimentary phase from the shelf to the deep sea on the transgressive Yangtze platform;this indicates that the δ^(34)SO_(4)^(2−)values in seawater must be differently distributed in depositional *** sulfur in the Ni-Mo layer is produced after the mixing of seawater and hydrothermal fluid,while the V layer mainly originates from ***,the Ni-Mo and V deposits have been differentiated primarily on the basis of the combined effect of continental weathering and hydrothermal fluid.

关键词： sedimentary environment black shale polymetallic layer pyrite early Cambrian

Mitigating set-stuck failure in 3D phase change memory: substituting square pulses with surge pulses

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Science China(Information Sciences) 2024年第5期67卷 295-301页

作者： Ninghua li Wang cai Jun XIANG Hao TONG Weiming CHENG Xiangshui MIAO School of Integrated Circuits Huazhong University of Science and Technology Hubei Yangtze Memory Laboratories Hubei Institute of Measurement and Testing Technology

In the devices that integrate phase change memory(PCM) and ovonic threshold switching(OTS),the OTS threshold voltage often surpasses the RESET operation voltage of PCM. The conventional application of square pulses hinders the successful completion of the SET operation in these integrated devices. To address this challenge, a novel pulse called the surge pulse is introduced, which comprises a high amplitude pulse for OTS activation and a low amplitude pulse for PCM operation. By employing COMSOL simulation,the operational effectiveness of both square pulses and surge pulses is validated. Test results reveal that using a square pulse to operate the integrated device accelerates the occurrence of SET-stuck failure(SSF).In contrast, the surge pulse enables the integrated device to operate for at least 1000 cycles while preserving the essential cyclic characteristics. Additionally, an investigation into the overshoot component of the surge pulse is conducted, revealing that an increase in overshoot amplitude and pulse width also accelerates the emergence of SSF. By applying the theory of ion migration induced by the electric field, the root cause of SSF in integrated devices is explained, and the accuracy of the theory is validated through the application of a reverse pulse. In summary, this study elucidates the rationality of replacing the square pulse with a surge pulse, presenting a superior approach for operating PCM and OTS integrated devices.

关键词： surge pulse phase change memory (PCM) integration SET-stuck failure (SSF) square pulse

Uncovering the coupling effect with energy-related carbon emissions and human development variety in Chinese provinces

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Journal of Environmental Sciences 2024年第5期139卷 527-542页

作者： liu Chen Yiqi Tan Gengpei Lv Weiguang cai Xiaofeng Gao Rui li School of Management Science and Real Estate Chongqing UniversityChongqing 400044China State Key Joint Laboratory of Environment Simulation and Pollution Control(SKLESPC) School of EnvironmentTsinghua UniversityBeijing 100084China Key Laboratory of the Three Gorges Reservoir Region’s Eco-Environment Ministry of EducationCollege of Environment and EcologyChongqing UniversityChongqing 400044China

Lessening energy-related carbon emissions has become a crucial measure to achieve Chinese carbon *** study is the first to construct a Difference in Carbon pressures-adjusted Human Development Index(DCHDI)model for the purpose of exploring the coupling effect between carbon emissions and human development variety from 2000 to 2019 in Chinese *** demonstrate the following.(1)The total energy-related carbon footprint of 30 provinces in China reached 10.2 billion tons in 2019,with an average annual growth rate of 6.93% over the past two decades;and the provinces with the highest carbon emissions per capita are InnerMongolia,Ningxia,and Shanxi.(2)At the provincial level,we observed that the Human Development Index(HDI),which includes life expectancy,education,and income,has been rising,while Beijing,Shanghai,and Tianjin entered the super-high HDI level before 2008.(3)The entire coupling effect of 30 Chinese provinces has been broadly fortified in the last 20 years,but the growth rate of DCHDI values in 2011-2019 has slowed down compared with that in 2000-2010;the clustering phenomenon demonstrated that this discovery is associated with historical peaks in total carbon emissions.(4)The co-ordination degree of carbon emissions per capita and HDI was verified,and 96% of the data points were found in the range of super high coupling coordination ***,this study provides the government with worthwhile guidance for decision-making and carbon reduction strategies for other countries struggling to advance human sustainable development.

关键词： Energy-related carbon emissions Human sustainable development DCHDI model Coupling effect Chinese provinces

Simultaneously enhancing the strength and ductility of as-extruded AlN/AZ91 composites via nano-precipitation and pyramidal slip

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Journal of Materials Science & Technology 2024年第5期172卷 240-254页

作者： Bin Zhang Yunxia Sun Tuo liang Yunzhen li Tian li Jingchao Wang Ruiru cai Changlin Yang State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China

Age hardening is often used to optimize the mechanical properties of as-deformed Mg-based materials in industry,whereas the improvement of strength is usually accompanied by the significant loss of ductility,which hinders the application of Mg-based materials in structural *** the present work,high strength-ductility synergy(the yield strength of 263±9 MPa,ultimate tensile strength of 398±7 MPa and elongation to fracture of 34%±1%)was realized in as-extruded AlN/AZ91 composites after optimiz-ing aging *** characterization shows that AlN particles induced a large number of geometrically necessary dislocations around the AlN/Mg interface during extrusion,which decreased the nucleation barrier and provided more heterogeneous nucleation sites forγ-Mg 17 Al 12 continuous ***,95%of residual dislocations in as-extruded AlN/AZ91 composites were annihilated dur-ing peak-aging,suppressing the growth and coarsening of continuous ***,high density of nano-sizedγ-Mg 17 Al 12 continuous precipitates was produced in as-extruded AlN/AZ91 composites af-ter *** tension,gliding dislocations bypassed sphericalγ-Mg 17 Al 12 nano-precipitates by Orowan looping rather than cutting mechanism,which induced a strong block on dislocation *** high yield strength was mainly attributed to the high density of non-shearableγ-Mg 17 Al 12 nano-precipitates with spherical morphology,which was different from other Mg-Al-based *** results of texture evolution and slip trace analysis demonstrated that the suppression of extension twinning and less basal slip was due to the enhanced activity of pyramidalc+aslip in as-extruded AlN/AZ91 com-posites after peak-aging during the room temperature tension,meanwhile,the dislocation density of as-extruded AlN/AZ91 composites was significantly decreased during peak-aging,then higher elongation to fracture was achieved.

关键词： Magnesium matrix composites Mechanical properties Precipitation Deformation mechanisms Non-basal slip