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基于改进YOLOv5s的桥梁螺栓缺陷识别方法

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吉林大学学报（工学版） 2024年第3期54卷 749-760页

作者：张洪朱志伟胡天宇龚燕峰周建庭重庆交通大学省部共建山区桥梁及隧道工程国家重点实验室重庆400074 重庆交通大学信息科学与工程学院重庆400074 重庆交通大学航运与船舶工程学院重庆400074

针对现有算法在检测桥梁螺栓缺陷时因螺栓背景复杂和尺寸较小而导致的特征提取不充分、目标定位不精确问题,提出了一种基于改进YOLOv5s的桥梁螺栓缺陷识别方法。该方法在骨干网络中引入注意力机制以提升模型对螺栓特征的提取能力并加深... 详细信息

针对现有算法在检测桥梁螺栓缺陷时因螺栓背景复杂和尺寸较小而导致的特征提取不充分、目标定位不精确问题,提出了一种基于改进YOLOv5s的桥梁螺栓缺陷识别方法。该方法在骨干网络中引入注意力机制以提升模型对螺栓特征的提取能力并加深对螺栓全局特征的关注度;优化空间金字塔池化结构以减少螺栓特征信息流失;采用MPDIoU作为边界框回归损失函数,提高螺栓边界框的回归精度;将YOLO检测头解耦以消除目标检测中分类任务和回归任务共享检测头对边界框位置回归的负面影响。在螺栓锈蚀、螺栓松动、螺栓脱落和螺母脱落4类典型缺陷螺栓以及正常螺栓的3810张自制螺栓图像数据集上进行训练和测试,实验结果表明:本文算法对螺栓缺陷的检测精度达到90.8%,相较于YOLOv5s提升了3%,均值平均精度达到92.6%,相较于YOLOv5s提升了4.3%,可以应用于桥梁螺栓的缺陷智能识别。

关键词：桥梁工程螺栓缺陷识别 YOLOv5s 桥梁螺栓

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超长咸潮期间松浦取水应急支援青草沙原水系统

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中国给水排水 2024年第12期40卷 89-93页

作者：余梁蒋旭金晶石林钟文良朱志伟上海城投原水有限公司上海200000

位于长江口的青草沙原水系统承担着上海市中心城区60%以上的原水供应任务。受2022年8月以来长江流域持续干旱和台风的接连影响,青草沙水库遭受咸潮入侵,取水受限。在此背景下,黄浦江上游原水应急支援青草沙原水系统,松浦大桥泵站在原水... 详细信息

位于长江口的青草沙原水系统承担着上海市中心城区60%以上的原水供应任务。受2022年8月以来长江流域持续干旱和台风的接连影响,青草沙水库遭受咸潮入侵,取水受限。在此背景下,黄浦江上游原水应急支援青草沙原水系统,松浦大桥泵站在原水切换支援青草沙系统过程中,在最大设计供水流量下通过水泵调速提高供水效率。总结了应急供水期间的设备保障和运行管理措施,黄浦江的水质变化以及通过投加粉末活性炭优化供水水质的做法。

关键词：咸潮黄浦江青草沙水库应急供水原水切换粉末活性炭

A note on the perturbed monomial mapping

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Applied Mathematics(A Journal of Chinese Universities) 2019年第1期34卷 76-81页

作者： QU Cheng-qin zhu zhi-wei ZHOU Zuo-ling Department of Applied Mathematics South China University of Technology School of Mathematics and Statistics Zhaoqing University Lingnan College Sun Yat-sen University

In this paper, we present a necessary and suffcient condition that the perturbed monomial mapping is ergodic on a sphere S_(p-1)(1), which is in a combination with Anashin's earlier results about the perturbed monomial ergodic mappings on a sphere S_(p-r)(1), r > 1, completely solve a problem posed by A. Khrennikov about the ergodicity of a perturbed monomial mapping on a sphere.

关键词： perturbed monomial mapping ergodic p-adic integers

INTERDECADAL CHANGE IN THE RELATIONSHIP BETWEEN SOUTH CHINA SPRING RAINFALL AND PRECEDING-SUMMER WARM POOL OCEAN HEAT CONTENT

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Journal of Tropical Meteorology 2019年第4期25卷 462-470页

作者： WANG Xiao-fang CHANG Yue zhu zhi-wei Zhongshan Meteorological Service ZhongshanGuangdong 528401 China Guangdong Meteorological Service Guangzhou 510641 China Key Laboratory of Meteorological Disaster.Ministry of Education(K.LME)/Joint Intemational Research Laboratory of Climate and Environment Change(ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(C1C-FEMD) Nanjing University of Infonnation Science and TechnologyNanjing 210044 China

South China spring rainfall(SCSR) is a unique feature during the seasonal transition from the winter half-year to summer half-year. Abnormal SCSR has great impacts on crop harvests. Seeking previous predictability sources, particularly persistent precursors, is of practical importance in the seasonal prediction of SCSR. The present study investigates the relationship between SCSR and preceding-summer warm pool ocean heat content(WPHC). The SCSR-WPHC relationship is not stationary and has a remarkable interdecadal change around 1983. Before 1983, SCSR and preceding-summer WPHC have a close relationship, with a temporal correlation coefficient(TCC) of-0.54. After1983, the relationship disappears, with a TCC of-0.18. It is further found that the WPHC-associated sea surface temperature anomaly(SSTA) pattern in the simultaneous spring during the two periods presents dissimilar evolutionary features. Before 1983, a La Ni?a-like SSTA presents a fast transition during winter and alters to a developing El Ni?o during the following spring. The warm SSTA is confined to a limited region over the eastern Pacific. Therefore, the rainfall and circulation responses over the equatorial Maritime Continent are relatively weak. In turn, the Rossby wave response in terms of the cyclonic anomaly to the Maritime Continent diabatic heating is weak and confined to the South China Sea and Philippine Sea, which leads to high pressure and suppressed rainfall over south China, establishing an intimate SCSR-WPHC relationship. However, after 1983, because the La Ni?a-like SSTA pattern can persist for more than a year, the rainfall diabatic heating over the Maritime Continent during springtime is enhanced, resulting in a much larger cyclonic response over East Asia but insignificant rainfall anomalies over south China. Therefore, the SCSR-WPHC relationship becomes weak. Wavelet analysis suggests that the change in the dominant period of WPHC variation is probably responsible for the different SSTA

关键词： south China spring rainfall warm pool ocean heat content interdecadal change

A Low Cost, Green Sustainable and Biodegradable Biomass-based Fluorine-free Water and Oil Repellent

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Chinese Journal of Polymer Science 2024年第4期42卷 480-491页

作者： zhi-wei Shen Shu-Feng Hu Chen Zeng wei-Qing Kong Mei-Fang zhu State Key Laboratory for Modification of Chemical Fibers&Polymer Materials College of Materials Science and EngineeringDonghua UniversityShanghai201620China State Key Laboratory of Pulp and Paper Engineering School of Light Industry and EngineeringSouth China University of TechnologyGuangzhou510630China

With the global ban on plastics intensifying, the substitution of plastic with paper has garnered increasing attention. However, the inadequate water and oil repellency of pulp molding hinders its practical applications. Currently, the common method to enhance the oil and water repellency of pulp molding is by adding fluorinated water and oil repellents. Nevertheless, fluorinated compounds are environmentally and physiologically harmful. Therefore, the development of fluorine-free, water and oil repellent alternatives is crucial. In this study, chitosan and stearic acid were utilized as the first and second layers of the oil and water repellent coatings, respectively. The coated samples exhibited favorable water repellency, with a water contact angle of 116.4°, and excellent oil repellency, achieving a 12/12 rating on the kit scale. Importantly, the samples did not exhibit any leakage after being soaked in hot water and hot oil at 95±5℃ for 30 min, demonstrating remarkable performance as a barrier against hot water and oil. Moreover, the coated samples displayed outstanding mechanical properties, thermal stability, biodegradability, and recyclability. The approach presented in this study is simple, cost-effective, environmentally friendly, and represents a promising technique for producing fluoride-free, oil-and water-resistant pulp molding products.

关键词： Biomass Fluoride-free Oil-andwater-resistant Plasticfree

High Speed Sintering:Assessing the Influence of Energy Input on Microstructure and Mechanical Properties of Polyether Block Amide(PEBA)Parts

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Chinese Journal of Polymer Science 2024年第5期42卷 675-682,I0004,I0010页

作者： Jiang-Tao Sun zhi-Yong Fan Yi-wei Mao wei Li wei zhu Dao-Sheng Cai Qing-Song wei State Key Laboratory of Materials Processing and Die&Mould Technology Huazhong University of Science and TechnologyWuhan430074China State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan430074China National Engineering Research Centre for High Efficiency Grinding Hunan UniversityChangsha410082China Wuhan EasyMFG Technology CO. LTDWuhan430074China

High speed sintering,a new powder-bed fusion additive manufacturing technology,utilizes infrared lights(IR)to intensely heat and melt polymer *** presence of defects such as porosity,which is associated with particle coalescence,is highly dependdent on the level of energy *** study investigate the influcence of energy input on porosity and its subsequent effects on the mechanical properties and microstructures of PEBA *** parts were manufactured with a variety of lamp powers,resulting in a range of energy input levels spanning from low to ***,they underwent testing using Archimedes’method,followed by tensile *** porosity,mechanical characteristics,and energy input exhibit a strong correlation;inadequate energy input was the primary cause of pore *** the reduced IR light power resulted in the following outcomes:porosity,ultimate tensile strength,and elongation of 1.37%,7.6 MPa,and 194.2%,*** the energy input was further increased,the porosity was reduced to as low as 0.05%and the ultimate tensile strength and elongation were increased to their peak values of 233.8%and 9.1 MPa,respectively.

关键词： High speed sintering Additive manufacturing Energy input Powder bed fusion PEBA

Electromagnetic scattering and imaging simulation of extremely large-scale sea-ship scene based on GPU parallel technology

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Journal of Electronic Science and Technology 2024年第2期22卷 16-23页

作者： Cheng-wei Zhang zhi-Qin Zhao wei Yang Li-Lai Zhou Hai-Yu zhu Southwest China Institute of Electronic Technology Chengdu610036China School of Electronic Science and Engineering University of Electronic Science and Technology of ChinaChengdu611731China Tencent Company Shenzhen518054China

Aiming to solve the bottleneck problem of electromagnetic scattering simulation in the scenes of extremely large-scale seas and ships,a high-frequency method by using graphics processing unit(GPU)parallel acceleration technique is *** the implementation of different electromagnetic methods of physical optics(PO),shooting and bouncing ray(SBR),and physical theory of diffraction(PTD),a parallel computing scheme based on the CPU-GPU parallel computing scheme is realized to balance computing ***,a multi-GPU framework is further proposed to solve the computational difficulty caused by the massive number of ray tubes in the ray tracing *** using the established simulation platform,signals of ships at different seas are simulated and their images are achieved as *** is shown that the higher sea states degrade the averaged peak signal-to-noise ratio(PSNR)of radar image.

关键词： Multi graphics processing unit Radar imaging Sea-ship Shooting and bouncing rays

Optical Transient Source AT2021lfa:A Possible“Dirty Fireball”

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Research in Astronomy and Astrophysics 2024年第4期24卷 124-133页

作者： Xue-Mei Ye Da-Ming wei Yi-Ming zhu zhi-Ping Jin Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China National Astronomical Observatories/Nanjing Institute of Astronomical Optics&Technology Chinese Academy of SciencesNanjing 210042China CAS Key Laboratory of Astronomical Optics&Technology Nanjing Institute of Astronomical Optics&TechnologyNanjing 210042China

AT2021lfa,also known as ZTF21aayokph,was detected by the Zwicky Transient Facility on 2021 May 4,a 05:34:48 ***-up observations were conducted using a range of ground-based optical telescopes,as wel as Swift/XRT and VLA ***2021lfa is classified as an“orphan afterglow”candidate due to its rapid flux decline and its reddened color(g-r=0.17±0.14 mag).For an optical transient source without promp gamma-ray detection,one key point is to determine its burst *** we measure the burst time through fitting the initial bump feature of AT2021lfa and obtain its burst time as 2021 May 3,at 22:09:50 *** afterglowpy,we model the multi-band afterglow of AT2021lfa and find that the standard model canno reproduce the late radio observations *** that the microphysical parameters ε_(e),ε_(B)(the energy fraction given to electrons and magnetic field),andξN(the fraction of accelerated electrons)may vary with time we then model the afterglow of AT2021lfa taking into account the temporal evolution of the physical parameters ε_(e),ε^(B),and ξ_(N) and find in this case the multi-wavelength observations can be reproduced *** initial Lorentz factor of AT2021lfa can be estimated from the peak time of the early afterglow,which yields a value of about 18 suggesting that AT2021lfa should be classified as a“dirty fireball.”From the upper limit for the prompt emission energy of AT2021lfa,we obtain that the radiation efficiency is less than 0.02%,which is much smaller than that of ordinary gamma-ray bursts(GRBs).It is also interesting that the fitted values of jet angle and viewing angle are very large,θ_(c)~0.66 rad,θ_(v)~0.53 rad,which may lead to the low Lorentz factor and radiation *** compared with GRB afterglow samples,it is evident that the onset bump timescale of AT2021lfa satisfies the empirical relationships observed in GRB ***,the luminosity of AT2021lfa falls within the range of observations for GRB samples;howeve

关键词： gamma-rays:ISM methods:numerical radiation mechanisms:non-thermal

A function-based behavioral modeling method for air combat simulation

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Journal of Systems Engineering and Electronics 2024年第4期35卷 945-954页

作者： WANG Tao zhu zhi ZHOU Xin JING Tian CHEN wei College of Systems Engineering National University of Defense TechnologyChangsha 410073China Institute of Communication and Navigation Air Force Research AcademyBeijing 100085China

Today’s air combat has reached a high level of uncertainty where continuous or discrete variables with crisp values cannot be properly represented using fuzzy sets. With a set of membership functions, fuzzy logic is well-suited to tackle such complex states and actions. However, it is not necessary to fuzzify the variables that have definite discrete ***, the aim of this study is to improve the level of model abstraction by proposing multiple levels of cascaded hierarchical structures from the perspective of function, namely, the functional decision tree. This method is developed to represent behavioral modeling of air combat systems, and its metamodel,execution mechanism, and code generation can provide a sound basis for function-based behavioral modeling. As a proof of concept, an air combat simulation is developed to validate this method and the results show that the fighter Alpha built using the proposed framework provides better performance than that using default scripts.

关键词： air combat behavioral modeling intelligent agent