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Surface Defect Detection and Evaluation Method of Large Wind Turbine Blades based on an Improved Deeplabv3+Deep Learning Model

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Structural Durability & Health Monitoring 2024年第5期18卷 553-575页

作者： Wanrun Li Wenhai Zhao Tongtong Wang Yongfeng Du Institution of earthquake Protection and Disaster Mitigation Lanzhou University of TechnologyLanzhou730050China International Research base on Seismic Mitigation and Isolation of GANSU Province Lanzhou University of TechnologyLanzhou730050China Disaster Prevention and Mitigation Engineering Research Center of Western Civil Engineering Lanzhou University of TechnologyLanzhou730050China

The accumulation of defects on wind turbine blade surfaces can lead to irreversible damage,impacting the aero-dynamic performance of the *** address the challenge of detecting and quantifying surface defects on wind turbine blades,a blade surface defect detection and quantiﬁcation method based on an improved Deeplabv3+deep learning model is ***,an improved method for wind turbine blade surface defect detection,utilizing Mobilenetv2 as the backbone feature extraction network,is proposed based on an original Deeplabv3+deep learning model to address the issue of limited ***,through integrating the concept of pre-trained weights from transfer learning and implementing a freeze training strategy,signiﬁcant improvements have been made to enhance both the training speed and model training accuracy of this deep learning ***,based on segmented blade surface defect images,a method for quantifying blade defects is *** method combines image stitching algorithms to achieve overall quantiﬁcation and risk assessment of the entire *** results show that the improved Deeplabv3+deep learning model reduces training time by approximately 43.03%compared to the original model,while achieving mAP and MIoU values of 96.87%and 96.93%,***,it demonstrates robustness in detecting different surface defects on blades across different *** application of a blade surface defect quantiﬁcation method enables the precise quantiﬁcation of dif-ferent defects and facilitates the assessment of risk levels associated with defect measurements across the entire *** method enables non-contact,long-distance,high-precision detection and quantiﬁcation of surface defects on the blades,providing a reference for assessing surface defects on wind turbine blades.

关键词： Structural health monitoring computer vision blade surface defects detection Deeplabv3+ deep learning model

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Bifurcation analysis and control study of improved full-speed differential model in connected vehicle environment

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Chinese Physics B 2024年第7期33卷 245-266页

作者：艾文欢雷正清李丹洋方栋梁刘大为 College of Computer science and Engineering Northwest Normal UniversityLanzhou 730070China College of Electrical Engineering Lanzhou Institute of TechnologyLanzhou 730050China

In recent years, the traffic congestion problem has become more and more serious, and the research on traffic system control has become a new hot spot. Studying the bifurcation characteristics of traffic flow systems and designing control schemes for unstable pivots can alleviate the traffic congestion problem from a new perspective. In this work, the full-speed differential model considering the vehicle network environment is improved in order to adjust the traffic flow from the perspective of bifurcation control, the existence conditions of Hopf bifurcation and saddle-node bifurcation in the model are proved theoretically, and the stability mutation point for the stability of the transportation system is found. For the unstable bifurcation point, a nonlinear system feedback controller is designed by using Chebyshev polynomial approximation and stochastic feedback control method. The advancement, postponement, and elimination of Hopf bifurcation are achieved without changing the system equilibrium point, and the mutation behavior of the transportation system is controlled so as to alleviate the traffic congestion. The changes in the stability of complex traffic systems are explained through the bifurcation analysis, which can better capture the characteristics of the traffic flow. By adjusting the control parameters in the feedback controllers, the influence of the boundary conditions on the stability of the traffic system is adequately described, and the effects of the unstable focuses and saddle points on the system are suppressed to slow down the traffic flow. In addition, the unstable bifurcation points can be eliminated and the Hopf bifurcation can be controlled to advance, delay, and disappear,so as to realize the control of the stability behavior of the traffic system, which can help to alleviate the traffic congestion and describe the actual traffic phenomena as well.

关键词： bifurcation analysis vehicle queuing bifurcation control Hopf bifurcation

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Critical Opalescence and Its Impact on the Jet Quenching Parameter q

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Chinese Physics Letters 2024年第3期41卷 23-29页

作者：武警曹杉杉李峰 School of Physical science and Technology Lanzhou UniversityLanzhou 730000China institute of Frontier and Interdisciplinary science Shandong UniversityQingdao 266237China Research Center for Hadron and CSR Physics Lanzhou University and Institute of Modern Physics of CASLanzhou 730000China lanzhou Center for Theoretical Physics Key Laboratory of Theoretical Physics of Gansu Provinceand Frontiers Science Center for Rare IsotopesLanzhou UniversityLanzhou 730000China Frontiers science Center for Rare Isotopes Lanzhou UniversityLanzhou 730000China

Jet quenching parameter q is essential for characterizing the interaction strength between jet partons and nuclear *** on the quark-meson model,we develop a new framework for calculating q at finite chemical potential... 详细信息

关键词： parameter quark calculating

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Evaluation of the energy budget of thermokarst lake in permafrost regions of the Qinghai-Tibet Plateau

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Advances in Climate Change Research 2024年第4期15卷 636-646页

作者： Ze-Yong GAO Fu-Jun NIU Yi-Bo WANG Jing LUO Guo-An YIN Yun-Hu SHANG Zhan-Ju LIN Key Laboratory of Cryospheric science and Frozen Soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of ScienceLanzhou 730000China College of Earth and Environment science Lanzhou UniversityLanzhou 73000China

Thermokarst lake formation accelerates permafrost degradation due to climate warming,thereby releasing significant amounts of carbon into the atmosphere,complicating hydrological cycles,and causing environmental ***,the energy transfer mechanism from the surface to the sediment of thermokarst lakes remains largely unexplored,thereby limiting our understanding of the magnitude and duration of biogeochemical processes and hydrological ***,herein,a typical thermokarst lake situated in the center of the Qinghai-Tibet Plateau(QTP)was selected for observation and energy budget *** results showed that the net radiation of the thermokarst lake surface was 95.1,156.9,and 32.3 W m^(-2) for the annual,ice-free,and ice-covered periods,respectively,and was approximately 76%of the net radiation consumed by latent heat *** in heat storage in the thermokarst lake initially increased from January to April,then decreased from April to December,with a maximum change of 48.1 W m^(-2) in *** annual average heat fuxes from lake water to sediments were 1.4 W m^(-2);higher heat fluxes occurred during the ice-free season at a range of 4.9-12.0 W m^(-2).The imbalance between heat absorption and release in the millennium scale caused the underlying permafrost of the thermokarst lake to completely *** present,the ground temperature beneath the lake bottom at a depth of 15 m has reached 2.0℃.The temperatures and vapor-pressure conditions of air and lake surfaces control the energy budget of the thermokarst *** findings indicate that changes in the hydrologic regime shifts and biogeochemical processes are more frequent under climate warming and permafrost degradation.

关键词： Qinghai-Tibet Plateau Thermokarst lake Energy budget Permafrost degradation Hydrological cycle

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Reliability of DC-link capacitor in pulsed power supply for accelerator magnet

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Nuclear science and Techniques 2024年第9期35卷 28-40页

作者： Jie Wang Da-Qing Gao Wan-Zeng Shen Hong-Bin Yan Li-Jun Mao institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China School of Nuclear science and Technology Lanzhou UniversityLanzhou 730000China School of Nuclear science and Technology University of Chinese Academy of SciencesBeijing 100049China

Capacitors are widely used in pulsed magnet power supplies to reduce ripple voltage,store energy,and decrease power *** this study,DC-link capacitors in pulsed power supplies were *** deriving an analytical method for the capacitor current on the H-bridge topology side,the root-mean-square value of the capacitor current was calculated,which helps in selecting the DC-link *** proposed method solves this problem quickly and with high *** current reconstruction of the DC-link capacitor is proposed to avoid structural damage in the capacitor’s current measurement,and the capacitor’s hotspot temperature and temperature rise are calculated using the FFT *** test results showed that the error between the calculated and measured temperature increases was within 1.5℃.Finally,the lifetime of DC-link capacitors was predicted based on Monte Carlo *** proposed method can evaluate the reliability of DC-link capacitors in a non-isolated switching pulsed power supply for accelerators and is also applicable to film capacitors.

关键词： Aluminum electrolytic capacitor DC-link current DC–DC power converter Hotspot temperature

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Efficient nitrite-to-ammonia electroreduction over Zr-Ni frustrated Lewis acid-base pairs

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science China Chemistry 2024年第5期67卷 1707-1714页

作者： Ying Zhang Zhuohang Li Wenyu Du Kai Chen Ke Chu School of Materials science and Engineering Lanzhou Jiaotong UniversityLanzhou 730070China

Electrochemical NO_(2)~--to-NH_(3) conversion(NO_(2)RR) offers a green route to NH_(3) electrosynthesis, while developing efficient NO_(2)RR catalysis systems at high current densities remains a grand challenge. Herein, we report an efficient Zr-NiO catalyst with atomically dispersed Zr-dopants incorporated in NiO lattice, delivering the exceptional NO_(2)RR performance with industriallevel current density(>0.2 A cm^(-2)). In situ spectroscopic measurements and theoretical simulations reveal the construction of ZrNi frustrated Lewis acid-base pairs(FLPs) on Zr-Ni O, which can substantially increase the number of absorbed nitrite(NO_(2)~-),promote the activation and protonation of NO_(2)~- and concurrently hamper the H coverage, boosting the activity and selectivity of Zr-NiO towards the NO_(2)RR. Remarkably, Zr-NiO exhibits the exceptional performance in a flow cell with high Faradaic efficiency for NH_(3) of 94.0% and NH_(3)yield rate of 1,394.1 μmol h^(-1)cm^(-2) at an industrial-level current density of 228.2 m A cm^(-2),placing it among the best NO_(2)RR electrocatalysts for NH_(3) production.

关键词： electrochemical nitrite-to-ammonia conversion frustrated Lewis acid-base pairs(FLPs) in situ spectroscopy theoretical computations

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Molecular design of recyclable thermosetting polyimide and its composite with excellent mechanical and tribological properties

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Friction 2024年第3期12卷 452-461页

作者： Xiaoyue WANG Zenghui YANG Tingmei WANG Qihua WANG Xinrui ZHANG Song LI Key Laboratory of science and Technology on Wear and Protection of Materials Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China Center of Materials science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China

Recyclability of thermosetting polymers and their composites is a challenge for alleviating environmental pollution and resource *** this study,solvent-recyclable thermosetting polyimide(PI)and its composite were successfully *** tensile strength,elongation at break,and Young’s modulus of PI are 108.70±7.29 MPa,19.35%±3.89%,and 2336.42±128.00 MPa,*** addition of reduced graphene oxide(RGO)not only enhances the mechanical properties of PI but also endows it with excellent tribological *** PI illustrates a high recycling efficiency of 94.15%,but the recycled composite exhibits inferior mechanical *** recycling and utilization of PI and its composite are realized through imine bonds(-C=N),which provides new guidance for solving the problem of environmental pollution and resource waste and is potential application in the field of sustainable tribology.

关键词： thermosetting polyimide(PI) recyclability dynamic covalent bonds friction and wear polymer composites

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Calculation of the energy dependence of fission fragments yields and kinetic energy distributions for neutron-induced ^(235)U fission

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Chinese Physics C 2024年第8期48卷 159-169页

作者： Ya-Ning Han Zheng Wei Yi-Xuan Wang Dong-Ying Huo Peng-Qi Zhang Ming Li Jun Ma Kang Wu Yong-Guang Zheng Yuan He Zhi-Yong Deng Tian-Zhi Jiang Xiang-Lin Zhuo Jin Li Yun Zhang Yu Zhang Jun-Run Wang Xiao-Dong Su Ze-En Yao School of Nuclear science and Technology Lanzhou UniversityLanzhou 730000China Engineering Research Center for Neutron Application Technology Ministry of EducationLanzhou UniversityLanzhou 730000China MOE Frontiers science Center for Rare Isotopes Lanzhou UniversityLanzhou 730000China School of Mathematics and Statistics Lanzhou UniversityLanzhou 730000China Nuclear Power institute of China Chengdu 610000China

Fission fragments yields and average total kinetic energy are fundamental nuclear data for nuclear energy applications and the study of nuclear *** fission products,such as ^(95)Zr,^(99)Mo,^(140)Ba,^(144)Ce,and ^(147)Nd,serve as burnup monitors,assessing the number of fissions induced by neutrons on ^(235)***,current experimental data for these fission products worldwide are inconsistent,introducing significant uncertainty into related scientific *** this study,we employed the Potential-driving Model to calculate the independent yields of ^(235)U and evaluate its advantages in such ***,we investigated the energy dependence of independent yields to select important ***,we calculated the cumulative yields of ^(95)Zr,^(99)Mo,^(140)Ba,^(144)Ce,and ^(147)Nd,and compared them with existing literature data to explore the energy dependence of fission products for ^(235)*** the lack of fission product yield data above 14.8 MeV,we extended our calculated incident neutron energy to 20 MeV,aiming to support future scientific *** Geant4 physical model does not consider the influence of incident neutron energy on the average total kinetic energy of fission fragments;thus,we introduced the excitation function of the total kinetic energy of fission fragments recommended by Madland et al.,which effectively describes the experimental data of the average total kinetic energy of fragments formed in ^(235)U *** this paper,we comprehensively discuss the energy dependence of fission product yields and average total kinetic energy.

关键词： ^(235)U(n f) potential-driving model fission yields kinetic energies energy dependence

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Design and high-power testing of offline conditioning cavity for CiADS RFQ high-power coupler

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Nuclear science and Techniques 2024年第9期35卷 18-27页

作者： Ruo-Xu Wang Yuan He Long-Bo Shi Chen-Xing Li Zong-Heng Xue Tian-Cai Jiang Xian-Bo Xu Lie-Peng Sun Zhou-Li Zhang institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China lanzhou University Lanzhou 730000China

To validate the design rationality of the power coupler for the RFQ cavity and minimize cavity contamination,we designed a low-loss offline conditioning cavity and conducted high-power *** offline cavity features two coupling ports and two tuners,operating at a frequency of 162.5 MHz with a tuning range of 3.2 *** the installation angle of the coupling ring and the insertion depth of the tuner helps minimize cavity *** performed electromagnetic structural and multiphysics simulations,revealing a minimal theoretical power loss of 4.3%.However,when the cavity frequency varied by110 kHz,theoretical power losses increased to10%,necessitating constant tuner adjustments during *** simulations indicated that increased cavity temperature did not affect frequency *** completion of the offline high-power conditioning platform,we measured the transmission performance,revealing a power loss of 6.3%,exceeding the theoretical *** utilized efficient automatic range scanning and standing wave resonant *** fully condition the power coupler,a 15°phase difference between two standing wave points in the condition-ing system was ***,the maximum continuous wave power surpassed 20 kW,exceeding the expected target.

关键词： RFQ cavity Power coupler Offline conditioning Resonant cavity

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Significantly Enhanced Melt Memory Effect of Metallocene-made Isotactic Polypropylene Containing Talc

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Chinese Journal of Polymer science 2024年第2期42卷 213-222,I0008页

作者： Hong-Wen Sun Fu-Shan Wang Yan Gao Fu-Qing Wei Jia-Chun Feng State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular ScienceFudan UniversityShanghai200433China lanzhou Petrochemical Corporation of PetroChina Lanzhou730060China lanzhou Petrochemical Research Center Petrochemical Research Institute of PetroChinaLanzhou730060China

The melt memory effect is a widely observed phenomenon in semi-crystalline polymers. In practical applications, various additives are usually introduced into polymers, which may affect their melt memory behavior. In this work, the effect of talc on the melt memory effect of metallocene-made isotactic polypropylene(M-PP) was investigated in detail by using the differential scanning calorimetry. The results indicated that the introduction of talc significantly strengthened the melt memory effect of M-PP. Specifically, the upper limit temperature of Domain II increased from 161 ℃ to 174 ℃, resulting in a substantial widening of the temperature range of Domain IIa from 1 ℃ to 14 ℃. Analysis of the crystal orientation of the M-PP containing talc cooled from various Ts suggested that the remarkably enhanced melt memory effect could be ascribed to the stabilization of oriented nuclei facilitated by talc. This stabilizing effect was likely attributable to the prefreezing effect or the sorption interaction between talc and the M-PP chains.

关键词： Metallocene-made isotactic polypropylene Talc Melt memory effect Crystal orientation

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