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Automatic Detection of Weld Defects in Pressure Vessel X-Ray Image Based on CNN

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Wuhan University Journal of Natural Sciences 2022年第6期27卷 489-498页

作者： XIAO Wenkai FENG xiang NAN Shuiyu ZHANG Linlin Department of Computer Science and Engineering.East China University of Science and Technology Shanghai 200237China Shanghai Engineering Research Center of Smart Energy Shanghai 201103China Shanghai Aino Industrial Technology CO..LTD.Shanghai 201612 China

The visual automatic detection method based on artificial intelligence has attracted more and more attention. In order to improve the performance of weld nondestructive defect detection,we propose DRepDet(Dilated RepPoints Detector). First, we analyze the weld defect dataset in detail and summarize the distribution characteristics of weld defect data, that is, the defect scale is very different and the aspect ratio distribution range is large. Second, according to the distribution characteristics of defect data, we design DResBlock module, and introduce dilated convolution with different dilated rates in the process of feature extraction to expand the receptive field and improve the detection performance of large-scale defects. Based on DResBlock and anchor-free detection framework RepPoints, we design DRepDet. Extensive experiments show that our proposed detector can detect 7 types of defects. When using combined dilated rate convolution network in detection, the AP50 and Recall50 of big defects are improved by 3.1% and 3.3% respectively, while the performance of small defects is not affected, almost the same or slightly improved. The final performance of the whole network is improved a large margin,with 6% AP50 and 4.2% Recall50 compared with Cascade RCNN and 1.4% AP50 and 2.9% Recall50 compared with RepPoints.

关键词： nondestructive testing depth learning weld defect detection convolutional neural networks dilated convolution

Properties　of　Speckle　Intensities　in　Near-Field　Optical　Regions　by　Numerical　Solutions　of　Wave　Equations

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Chinese Physics Letters 2004年第6期21卷 1057-1060页

作者： CHENGChuan-Fu RENXiao-Rong LIUChun-xiang ZHANGNing-Yu TENGShu-Yun XUZhi-Zhan ShanghaiInstituteofOpticsandFineMechanics ChineseAcademyofSciencesPOBox200-811Shanghai201800 DepartmentofPhysics ShandongNormalUniversityJinan250014 ShandongInstituteofArchitectureandEngineering Jinan250014

Starting from the electromagnetic wave equations and boundary conditions and using Green's integral theorem, we implement the rigorous numerical solutions of the speckle field produced by scattering of dielectric random surfaces in the optical near-field. The average sizes of speckle granules are enlarged very quickly with the increase of the distance in the range less than a wavelength. It is found that the speckle contrast in the near-field and in the neighbourhood region is inversely proportional to the square of lateral correlation length at its large values and linearly decreases with the roughness exponent.

关键词： Speckle

Induced Plasticity of a Brittle(La,Ce)-Based Bulk Metallic Glass by Surface Corrosion

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Acta Metallurgica Sinica(English Letters) 2016年第2期29卷 129-133页

作者： Ji-Juan Liu Ran Li Lian-xiang Fang Ju Wang Tao Zhang Key Laboratory of Aerospace Materials and Performance (Ministry of Education) School of Materials Science and Engineering Beihang University

Unexpected facture without any room-temperature plasticity severely limits potential structural applications of bulk metallic glasses （BMGs）, especially La-, Mg- and Fe-based ones. In this study, a simple free corrosion method was provided to improve the plasticity of a brittle （La, Ce）-based BMG by the introduction of high-density corrosion defects on the surface. The influences of immersing time in 0.1 mol/L H2SO4 aqueous solution on the surface morphology and mechanical properties of the BMG were evaluated. With increasing immersing time from 5 to 30 min, the degree of surface corrosion increased obviously, and the distribution of corrosion defects became more homogenous. In the samples, the yielding phenomenon and certain plasticity appeared up to 0.3% after the surface treatment. The yielding and plasticity can be attributed to easier nucleation of shear bands on the defect surface rather than on the glabrous surface. The results provided a novel method to improve the plasticity of BMGs.

关键词： Metallic glasses Corrosion plastic deformation mechanism Rapid solidification Microstructure

Influence of ion species on extraction characteristicsof mixed ion beams

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Chinese Physics B 2024年第9期33卷 444-449页

作者： Ao Xu Pingping Gan xiang Wan Yuanjie Shi Institute of Electronic Engineering China Academy of Engineering PhysicsMianyang 621999China

The spatial distributions of different kinds of ions are usually not completely the same in the process of *** order to study the reason for the different characteristics of ion extraction, a simplified simulation model of Cu+ andCr+ ions extraction process was established by 2D3V (two-dimensional in space and three- dimensional in velocity space)particle-in-cell (PIC) method. The effects of different extraction voltages from 0 V to 500 V on the density distribution ofCu+ and Cr+ ions and the change of plasma emission surface were analyzed. On the basis of this model, the ion densitydistribution characteristics of Cu+ ions mixed with Li+, Mg+, K+, Fe+, Y+, Ag+, Xe+, Au+, and Pb+ ions respectivelyunder 200-V extraction voltage are further simulated, and it is revealed that the atomic mass of the ions is the key reason fordifferent ion density distributions when different kinds of ions are mixed and extracted, which provides support for furtherunderstanding of ion extraction characteristics.

关键词： extraction ion species density distribution atomic mass

Magnetic Properties and Kinetics Parameters of Electroless Magnetic Loss CoFeB Films

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Journal of Iron and Steel Research International 2008年第1期15卷 89-94页

作者： LIU Chang-hui HE Hua-hui SHEN xiang LI Hai-hua School of Computer Science and Engineering Wuhan Institute Technology Wuhan 430073 Hubei China Department of Electronic Science and Technology Huazhong University of Science and Technology Wuhan 430074 Hubei China

Electroless CoFeB films with good soft magnetic properties were fabricated on polyester plastic substrate from sodium tartarate as a complexing *** plating rate of electroless CoFeB films is a function of concentration of sodium tetrahydroborate,pH of the plating bath,plating temperature and the metallic *** estimated regression coefficient b0-b3 confidence interval,residual error r and confidence interval rint were confirmed by a computer *** optimal composition of the plating bath was obtained and the dynamic electromagnetic parameters of films were measured in the 2-10 GHz *** 2 GHz,the μ＇,μ″ of the electroless CoFeB films were 304 and 76.6,respectively,as the concentration of reducer is 1 g/*** hysteresis loop of the deposited CoFeB films show a remanence close to the saturation magnetization and coercivity of about 55.7-127.4 A/*** loops along the hard axis display low anisotropic field Hk of 2 388-3 582 A/m.

关键词： electroless CoFeB deposits deposition rate multiple linear regression coercivity magnetic hysteresis loop

Gradient refractive structured NiCr thin film absorber for pyroelectric infrared detectors

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Chinese Physics B 2019年第6期28卷 419-423页

作者： Yunlu Lian He Yu Zhiqing Liang xiang Dong School of Optoelectronic Information University of Electronic Science and Technology of China (UESTC)

A gradient refractive structured NiCr film that has a high extinction coefficient at far infrared range(8-μm–24 μm) is presented as an absorber for pyroelectric infrared detectors. The absorber features high absorption efficiency due to the low reflection off the structured surface and high absorption across the film thickness. The refractive index and extinction coefficient are extracted using spectroscopic ellipsometry. It is found that the single NiCr film exhibits an increasing refractive index as the gas atmosphere pressure increases, hence the three-layer gradient NiCr absorber can be fabricated by adjusting the gas atmosphere pressure during sputtering deposition. Essential Macleod software has been used to generate an efficient film structure design and the calculations show similar absorptance trend compared to the experimental measurement result. The results indicate that the gradient refractive structured metal thin film absorber can provide high absorption for applications in thermal sensing.

关键词： pyroelectric infrared detector spectroscopic ellipsometry deposition thermal sensing

Influence of packing media on nitrogen removal in a subsurface infiltration system

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Journal of Environmental Sciences 2004年第1期16卷 153-156页

作者： ZHANGJian HUANGXia SHAOChang-fei LIUChao-xiang SHIHan-chang HUHong-ying LiuZhi-qiang EnvironmentalSimulationandPollutionControlStateKeyJointLaboratory DepartmentofEnvironmentalSciencesandEngineeringTsinghuaUniversityBeijing100084China DepartmentofEnvironmentalEngineering QingdaoInstituteofArchitectureandEngineeringQingdao266033China

Influence of packing media on nitrogen removal in a subsurface infiltration system was studied. System A was filled with loamy soil and system B was filled with mixed soil of 75% red clay with 25% cinder. Both systems were fed with sewage at the same hydraulic loading of 2 cm/d at continuous operation mode. The same excellent removal performances of COD and T-P could be achieved in both infiltration systems with removal rates about 85% and 98%, respectively. In system A, NH +_4-N removal rate was as high as 96.5% and T-N removal rate was relatively much lower as 55.7%. And in system B, NH +_4-N removal rate was as low as 75.4% and T-N removal rate was relatively much higher as 75.5%. The difference was attributed to different soil oxidation-reduction condition that was greatly influenced by soil texture in subsurface infiltration system. Loamy soil led to oxidative condition that was favorable to nitrification and disadvantageous to denitrification. The results were just adverse to the system filled with clay. Intermittent operation was adopted to improve nitrogen removal in system B. NH +_4-N removal rate could be increased to about 95% and T-N removal rate could be increased to about 90% at intermittent operation mode in system B. Analysis of nitrogen removal mechanisms indicated that nitrification-denitrification was the primary nitrogen removal path in subsurface infiltration system and crop uptake was another important nitrogen removal way. It was the key to improve the total N removal performance that a suitable packing soil was available to present favorable oxidation-reduction condition for simultaneous nitrification and denitrification.

关键词： subsurface infiltration system nitrogen removal oxidation-reduction potential soil texture

The Slow Dynamics of the Zero-Range Process in the Framework of the Traps Model

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Chinese Physics Letters 2012年第5期29卷 59-62页

作者： QI Kai TANG Ming CUI Ai-xiang FU Yan Web Sciences Center University of Electronic Science and Technology of ChinaChengdu 610054

The relaxation dynamics of the zero-range process (ZRP) has been an interesting *** this study,we set up the relationship between the ZRP and a model of traps,and investigate the slow dynamics of the ZRP in the framework of the trap *** statistical quantities such as the average rest time,the particle distribution,the two-time correlation function and the average escape time,we find that the particle interaction,especially the resulting condensation,can significantly influence the *** the stationary state,both the average rest time and the average escape time caused by the attraction among particles are obtained *** the transient state,a hierarchical nature of the aging dynamics is revealed by both simulations and scaling ***,by comparing the particle diffusion in both the transient state and the stationary state,we find that the closer the ZRP systems approach the stationary state,the more slowly the particles diffuse.

关键词： stationary dynamics transient

Improved Ant Colony-Genetic Algorithm for Information Transmission Path Optimization in Remanufacturing Service System

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Chinese Journal of Mechanical Engineering 2018年第6期31卷 106-117页

作者： Lei Wang Xu-Hui Xia Jian-Hua Cao xiang Liu Jun-Wei Liu Hubei Key Laboratory of Mechanical Transmission and Manufacturing Engineering Wuhan University of Science and Technology Wuhan 430081 China Center for Service Science and Engineering Wuhan University of Science and Technology Wuhan 430065 China

The information transmission path optimization(ITPO) can often a ect the e ciency and accuracy of remanufactur?ing service. However, there is a greater degree of uncertainty and complexity in information transmission of remanu?facturing service system, which leads to a critical need for designing planning models to deal with this added uncer?tainty and complexity. In this paper, a three?dimensional(3D) model of remanufacturing service information network for information transmission is developed, which combines the physic coordinate and the transmitted properties of all the devices in the remanufacturing service system. In order to solve the basic ITPO in the 3D model, an improved 3D ant colony algorithm(Improved AC) was put forward. Moreover, to further improve the operation e ciency of the algorithm, an improved ant colony?genetic algorithm(AC?GA) that combines the improved AC and genetic algorithm was developed. In addition, by taking the transmission of remanufacturing service demand information of certain roller as example, the e ectiveness of AC?GA algorithm was analyzed and compared with that of improved AC, and the results demonstrated that AC?GA algorithm was superior to AC algorithm in aspects of information transmission delay, information transmission cost, and rate of information loss.

关键词： Remanufacturing service Information transmission Path optimization Ant colony algorithm Genetic algorithm