检索结果-南通市图书馆

维普期刊数据库

Fracture mechanism of inclusions in thick plate center under tensile loading

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第5期31卷 1196-1209页

作者： Lei hu li-qin Zhang feng hu Guo-hong Zhang Kuan Zheng Collaborative Innovation Center for Advanced Steels Wuhan University of Science and TechnologyWuhan430081HubeiChina Department of Applied Physics Wuhan University of Science and TechnologyWuhan430081HubeiChina Analysis and Testing Center Wuhan University of Science and TechnologyWuhan430081HubeiChina

Segregation of solute atoms in the center of thick plates of the tempered steel can cause an inhomogeneous structural transformation and generate micron-sized inclusions,which leads to lamellar tearing of thick plate and decreases the plasticity and *** formation and fragmentation mechanisms of micron-sized inclusions,like MnS and(Nb,Ti)C,in the center of thick plates were investigated by using thermodynamic calculations,finite element simulations,and electron backscatter diffraction characterization *** results show that micron-sized inclusions nucleate and grow in the liquid phase,and under tensile loading,they exhibit three fragmentation *** local stress during the fragmentation of inclusions is lower than the critical fracture stress of adjacent grains,and phase boundaries can effectively impede crack propagation into the *** existence of a low proportion of high-angle grain boundaries(58.1%)and high Kernel average misorientation value(0.534°)in the segregation band promotes inclusions fragmentation and crack *** difference in crack initiation and propagation direction caused by the morphology of inclusions and physical properties,as well as different matrix arrest abilities,is the main reasons for the diversity of inclusion fragmentation.

关键词： Thick plate Inclusion Finite element simulation Critical fracture stress Fracture mechanism

Clinical heterogeneity and five phenotypes identified in pediatric Behçet’s syndrome: a cohort study from Shanghai Behçet’s syndrome database

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Pediatrics 2024年第8期20卷 801-808页

作者： Dan hu Chun-hui She hua-Fang Bao Jun Zou Jian-Fei Cai Jing‑fen Ye Yan Shen Hai‑fen Ma Dan Luo Jian-Long Guan Department of Rheumatology and Immunology Huadong Hospital Affiliated to Fudan University221 Yan’an West Road200040ShanghaiChina

Objectives Behçet’s syndrome(BS)is a rare disease of unknown etiology,with limited reports especially in pediatric *** clinical characteristics and phenotypes of pediatric BS as a highly heterogeneous variable vessel vasculitis were investigated in this *** A cross-sectional study was conducted to compare clinical variables and descriptive characteristics of BS by age of onset and *** analysis was then performed to identify the phenotypes of pediatric *** A total of 2082 BS patients were included in this study,1834 adults and 248 *** with adult-onset BS,pediatric BS had a higher incidence of folliculitis[relative risks(RR)and 95%confidence interval(CI)1.3(1.0–1.5)],uveitis of the left eye[RR and 95%CI 2.3(1.0–5.0)],intestinal ulcer complications[RR and 95%CI 2.1(1.1–4.2)],pericarditis[RR and 95%CI 2.5(1.0–6.2)],and psychiatric disorders[RR and 95%CI 2.8(1.0–7.9)],while the incidence of thrombocytopenia was lower[RR 0.2(0.1–1.0)].Among pediatric BS,females had more genital ulcers,while males were more likely to have skin lesions,panuveitis,vascular involvement,venous lesions,cardiac involvement,and aortic *** analysis classified pediatric BS into five clusters(C1–C5):C1(n=61,24.6%)showed gastrointestinal(GI)involvement;C2(n=44,17.7%)was the central nervous system(CNS)type where 23 cases overlapped joint involvement;in C3(n=35,14.1%),all patients presented with arthritis or arthralgia;all patients in C4(n=29,11.7%)manifested ocular involvement,with a few patients overlapping with GI involvement or joint damage;C5(n=79,31.9%)was the mucocutaneous type,presenting both oral ulcers,genital ulcers,and skin *** The clinical features of pediatric and adult BS differ *** and female pediatric BS also have a distinct *** phenotypes including GI,CNS,joint,ocular,and mucocutaneous types were identified for pediatric BS.

关键词： Behget's syndrome Clinical manifestation Cluster analysis-Pediatric Phenotype

Mn-modified nitrogen-doped Pt-based electrocatalyst for efficient oxygen reduction in aluminum-air batteries

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2024年第8期17卷 7126-7135页

作者： li Gao Yang Song Xuebing Xu Chang li Chaoquan hu State Key Laboratory of Mesoscience and Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China Zhongke Nanjing Institute of Green Manufacturing Industry Nanjing 211135China

In this study,a Mn-modified Pt-based catalyst loaded on nitrogen-doped Ketjen black(Mn-Pt/NKB)is prepared using a simple ethylene glycol reduction *** size of Pt nanoparticles(NPs)is effectively controlled by doping with Mn and *** the smallest average particle size of 1.7 nm,Mn-Pt/NKB demonstrates half-wave potentials of 0.890 and 0.688 V in the alkaline and neutral electrolytes,respectively,which are superior to those of commercial platinum on activated carbon(Pt/C).When applied as an air cathode in aluminum-air battery,it exhibits ultra-high power densities of 190(alkaline)and 26.2 mW·cm^(−2)(neutral).Moreover,the voltage remains stable after 5 h of *** practical application performance of the Mn-Pt/NKB catalyst in an aluminum-air battery is better than that of commercial Pt/***,the oxygen reduction reaction(ORR)mechanism on surfaces with different particle sizes is analyzed using density functional *** cracking is the major pathway on the surface of the small particles with lower energy consumption of 0.5 eV,while water molecule cleavage is the major pathway on the surface of the large particles with higher energy consumption of 0.97 *** lower energy consumption of the oxygen cracking pathway further confirms the ORR mechanism for higher activity on small-sized *** study provides a direction for the rational design of Pt-based catalysts for ORR and sheds light on the commercial development of aluminum-air batteries.

关键词： oxygen reduction reaction precious metal catalysts aluminum-air battery density functional theory(DFT)calculations reaction pathway

Fault diagnosis of a marine power-generation diesel engine based on the Gramian angular field and a convolutional neural network

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第6期25卷 470-482页

作者： Congyue li Yihuai hu Jiawei JIANG Dexin CUI Merchant Marine College Shanghai Maritime UniversityShanghai 201306China School of Mechanical and Energy Engineering Shanghai Technical Institute of Electronics&InformationShanghai 201411China

Marine power-generation diesel engines operate in harsh *** vibration signals are highly complex and the feature information exhibits a non-linear *** is difficult to extract effective feature information from the network model,resulting in low fault-diagnosis *** address this problem,we propose a fault-diagnosis method that combines the Gramian angular field(GAF)with a convolutional neural network(CNN).Firstly,the vibration signals are transformed into 2D images by taking advantage of the GAF,which preserves the temporal *** raw signals can be mapped to 2D image features such as texture and *** integrate the feature information,the images of the Gramian angular summation field(GASF)and Gramian angular difference field(GADF)are fused by the weighted average fusion ***,the channel attention mechanism and temporal attention mechanism are introduced in the CNN model to optimize the CNN learning *** the concept of residuals in the attention mechanism improves the feasibility of ***,the weighted average fused images are fed into the CNN for feature extraction and fault *** validity of the proposed method is verified by experiments with abnormal valve *** average diagnostic accuracy is 98.40%.When−20 dB≤signal-to-noise ratio(SNR)≤20 dB,the diagnostic accuracy of the proposed method is higher than 94.00%.The proposed method has superior diagnostic ***,it has a certain anti-noise capability and variable-load adaptive capability.

关键词： Multi-attention mechanisms(MAM) Convolutional neural network(CNN) Gramian angular field(GAF) Image fusion Marine power-generation diesel engine Fault diagnosis

Natural vibration and critical velocity of translating Timoshenko beam with non-homogeneous boundaries

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2024年第9期45卷 1523-1538页

作者： Yanan li Jieyu DING hu DING liqun CHEN Shanghai Institute of Applied Mathematics and Mechanics Shanghai Key Laboratory of Mechanics in Energy EngineeringShanghai Frontier Science Center of MechanoinformaticsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200072China School of Mathematics and Statistics Qingdao UniversityQingdao 266071Shandong ProvinceChina

In most practical engineering applications,the translating belt wraps around two fixed *** boundary conditions of the dynamic model are typically specified as simply supported or fixed *** this paper,non-homogeneous boundaries are introduced by the support *** the translating belt as the mechanical prototype,the vibration characteristics of translating Timoshenko beam models with nonhomogeneous boundaries are investigated for the first *** governing equations of Timoshenko beam are deduced by employing the generalized Hamilton's *** effects of parameters such as the radius of wheel and the length of belt on vibration characteristics including the equilibrium deformations,critical velocities,natural frequencies,and modes,are numerically calculated and *** numerical results indicate that the beam experiences deformation characterized by varying curvatures near the *** radii of the wheels play a pivotal role in determining the change in trend of the relative difference between two beam *** the results unearths that the relative difference in equilibrium deformations between the two beam models is more pronounced with smaller-sized *** the two wheels are of equal size,the critical velocities of both beam models reach their respective *** addition,the relative difference in natural frequencies between the two beam models exhibits nonlinear variation and can easily exceed 50%.Furthermore,as the axial velocities increase,the impact of non-homogeneous boundaries on modal shape of translating beam becomes more *** dealing with non-homogeneous boundaries is challenging,beam models with non-homogeneous boundaries are more sensitive to parameters,and the differences between the two types of beams undergo some interesting variations under the influence of non-homogeneous boundaries.

关键词： translating beam Timoshenko beam non-homogeneous boundary natural frequency critical velocity

维普期刊数据库

A new integrated model of deformation resistance and its application in prediction of rolling force of a thick plate

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第4期31卷 882-893页

作者： Shun-hu Zhang Yan li li-zhi Che Wen-hao Tian Shagang School of Iron and Steel Soochow UniversitySuzhou 215021JiangsuChina

The prediction accuracy of existing models of the rolling force of a thick plate is always very *** address this problem,a high-precision genetic algorithm-backpropagation network(GA-BP)model of deformation resistance was built,and its integration with the traditional fitted model was further ***,a novel rolling force model was obtained by embedding the integration model of deformation resistance in the original model of rolling *** to this research idea,the industrial data are normalized at *** this basis,the interactions among the process parameters were disclosed through the variance analysis,and then described by various virtual *** factors are set as part of input ***,the optimal structure of the GA-BP model of deformation resistance was determined and an integration model of deformation resistance was ***,a novel rolling force model is obtained by substituting the traditional fitted deformation resistance into the Sims model with the integration model of the deformation *** results proves that the introduction of virtual factors can increase the hit rate of±5%from 75.8%to 78%and can reduce the root mean square error from 4.72%to 4.48%.Besides,it is found that the mean relative error of the traditional fitted deformation resistance is 0.142,while that of the modified deformation resistance is only *** addition,the mean relative error in the original rolling force model is 0.145,while that of the present model is only 0.03.

关键词： Integration model-Deformation resistance Variance analysis Virtual factor Genetic algorithm-backpropagation network model

Stochastic LQ Control with Extra Measurability Restriction

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2024年第3期37卷 1003-1022页

作者： WANG Hongxia hu Yuxi li Zixing SONG lianfeng College of Electrical Engineering and Automation Shandong University of Science and TechnologyQingdao 266590China

Different from the standard linear quadratic(LQ)problem for stochastic systems,the LQ problem considered in the paper has extra measurability *** problem also appears in the LQ control problem for stochastic systems with delays,rational expectations problems,asymmetric information control,and so *** essential difficulty lies in that one has to optimize the input and its conditional expectations *** stochastic maximum principle(SMP)and orthogonal decomposition technique are the key ***,the authors establish the SMP and convert the original problem into forward and backward stochastic difference equations(FBSDEs)with extra measurability ***,the authors resolve the FBSDEs by using the orthogonal decomposition technique and obtain the analytical solution to the underlying ***,the authors explore the essential distinction between the problem and the standard stochastic LQ control ***,numerical examples are given to illustrate the obtained results.

关键词： Multiplicative noise systems optimal control stochastic maximum principle stochastic systems

维普期刊数据库

A novel metal-free porous covalent organic polymer for efficient room-temperature photocatalytic CO2 reduction via dry-reforming of methane

在线全文

学校读者我要写书评

暂无评论

Green Energy & Environment 2024年第9期9卷 1407-1418页

作者： Sheng-Yan Yin Ziyi li Yingcai hu Xiao Luo Jishan li College of Chemistry and Chemical Engineering Hunan University Institute of Basic Medicine and Cancer (IBMC) Chinese Academy of Sciences

At room temperature,the conversion of greenhouse gases into valuable chemicals using metal-free catalysts for dry reforming of methane（DRM） is quite promising and ***,we developed a novel covalent organic porous polymer （TPE-COP） with rapid charge separation of the electron–hole pairs for DRM driven by visible light at room temperature,which can efficiently generate syngas （CO and H2）.Both electron donor (tris（4-aminophenyl）amine,TAPA) and acceptor (4,4',4'',4'''-(（1 E,1'E,1''E,1'''E）-(ethene-1,1,2,2-tetrayltetrakis （benzene-4,1-diyl）)tetrakis （ethene-2,1-diyl）)tetrakis (1-（4-formylbenzyl）quinolin-1-ium),TPE-CHO) were existed in TPE-COP,in which the push–pull effect between them promoted the separation of photogenerated electron–hole,thus greatly improving the photocatalytic *** functional theory （DFT） simulation results show that TPE-COP can form charge-separating species under light irradiation,leading to electrons accumulation in TPE-CHO unit and holes in TAPA,and thus efficiently initiating *** 20 h illumination,the photocatalytic results show that the yields reach 1123.6 and 30.8μmol g-1for CO and H2,respectively,which are significantly higher than those of TPE-CHO small *** excellent result is mainly due to the increase of specific surface area,the enhancement of light absorption capacity,and the improvement of photoelectron-generating efficiency after the formation of ***,this work contributes to understanding the advantages of COP materials for photocatalysis and fundamentally pushes metal-free catalysts into the door of DRM field.

关键词： Metal-free Photocatalytic CO 2 reduction Covalent organic polymer Dry-reforming of methane Electron donor and acceptor

Evolution and conservation genetics of pangolins

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Integrative Zoology 2024年第3期19卷 426-441页

作者： Tongtong GU Jingyang hu li YU State Key Laboratory for Conservation and Utilization of Bio-Resource in Yunnan School of Life SciencesYunnan UniversityKunmingChina

Pangolins(Pholidota,Manidae)are classified as an evolutionarily distinct and globally endangered mammal due to their unique morphology(nail-like scales and a myrmecophagous diet)and being the victim of heavy poaching and worldwide *** such,pangolins serve as a textbook example for studying the special phenotypic evolutionary adaptations and conservation genetics of an endangered *** years have demonstrated significant advancements in the fields of molecular genetics and genomics,which have translated to a series of important research achievements and breakthroughs concerning the evolution and conservation genetics of *** review comprehensively presents the hitherto advances in phylogeny,adaptive evolution,conservation genetics,and conservation genomics that are related to pangolins,which will provide an ample understanding of their diversity,molecular adaptation mechanisms,and evolutionary *** addition,we highlight the priority of investigating species/population diversity among pangolins and suggest several avenues of research that are highly relevant for future pangolin conservation.

关键词： adaptive evolution conservation genetics conservation genomics pangolins phylogeny