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Deep-learning-assisted online surface roughness monitoring in ultraprecision fly cutting

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Science China(Technological Sciences) 2024年第5期67卷 1482-1497页

作者： SHEHZAD Adeel RUI XiaoTing DING YuanYuan ZHANG JianShu CHANG Yu LU HanJing CHEN YiHeng Institute of Launch dynamics Nanjing University of Science and TechnologyNanjing210094China National Key Laboratory of Complex Multibody System dynamics Nanjing210094China Automotive Engineering Centre University of Engineering and TechnologyLahore54890Pakistan School of Science Nanjing University of Science and TechnologyNanjing210094China College of Engineering Peking UniversityBeijing100871China

Surface roughness is one of the most critical attributes of machined components,especially those used in high-performance *** surface roughness monitoring offers advancements comparable to post-process inspection methods,reducing inspection time and costs and concurrently reducing the likelihood of ***,online monitoring approaches for surface roughness are constrained by several limitations,including the reliance on handcrafted feature extraction,which necessitates the involvement of human experts and entails time-consuming ***,the prediction models trained under one set of cutting conditions exhibit poor performance when applied to different experimental *** address these challenges,this work presents a novel deep-learning-assisted online surface roughness monitoring method for ultraprecision fly cutting of copper workpieces under different cutting *** acceleration signals were acquired during each cutting experiment to develop two datasets,and no handcrafted features were *** deep learning models were developed and evaluated using standard performance metrics.A convolutional neural network stacked on a long short-term memory network outperformed all other network models,yielding exceptional results,including a mean absolute percentage error as low as 1.51%and an R2value of 96.6%.Furthermore,the robustness of the proposed model was assessed via a validation cohort analysis using experimental data obtained using cutting parameters different from those previously *** performance of the model remained consistent and commendable under varied conditions,asserting its applicability in real-world scenarios.

关键词： online surface roughness monitoring UPFC deep learning CNN-LSTM vibration signal

Organization of microtubule plus-end dynamics by phase separation in mitosis

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Journal of Molecular Cell Biology 2024年第2期16卷 24-35页

作者： Fengrui Yang Mingrui Ding Xiaoyu Song Fang Chen Tongtong Yang Chunyue Wang Chengcheng Hu Qing Hu Yihan Yao Shihao Du Phil YYao Peng Xia Gregory Adams Jr Chuanhai Fu Shengqi Xiang Dan Liu Zhikai Wang Kai Yuan Xing Liu MOE Key Laboratory for Membraneless Organelles&Cellular dynamics Hefei National Research Center for Cross-disciplinary SciencesCenter for Advanced Interdisciplinary Science and Biomedicine of IHMDivision of Life Sciences and MedicineUniversity of Science&Technology of ChinaHefei 230027China Anhui Key Laboratory for Cellular dynamics and Chemical Biology University of Science&Technology of ChinaHefei 230027China Keck Center for Organoids Plasticity Morehouse School of MedicineAtlantaGA 30310USA Hunan Key Laboratory of Molecular Precision Medicine Central South UniversityChangsha 410083China

In eukaryotes,microtubule polymers are essential for cellular plasticity and fate ***-binding(EB)proteins serve as scaffolds for orchestrating microtubule polymer dynamics and are essential for cellular dynamics and chromosome segregation in ***,we show that EB1 forms molecular condensates with TIP150 and MCAK through liquid–liquid phase separation to compartmentalize the kinetochore–microtubule plus-end machinery,ensuring accurate kinetochore–microtubule interactions during chromosome segregation in *** of EB1–TIP150 polymer formation by a competing peptide prevents phase separation of the EB1-mediated complex and chromosome alignment at the metaphase equator in both cultured cells and Drosophila ***220 of EB1 is dynamically acetylated by p300/CBP-associated factor in early mitosis,and persistent acetylation at Lys220 attenuates phase separation of the EB1-mediated complex,dissolves droplets in vitro,and harnesses accurate chromosome *** data suggest a novel framework for understanding the organization and regulation of eukaryotic spindle for accurate chromosome segregation in mitosis.

关键词： phase separation mitosis microtubule dynamics EB1 acetylation

Perturbed low-thrust geostationary orbit transfer guidance via polynomial costate estimation

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Chinese Journal of Aeronautics 2024年第3期37卷 181-193页

作者： Zhao LI Hengnian LI Fanghua JIANG Junfeng LI State Key Laboratory of Astronautic dynamics Xi’an Satellite Control CenterXi’an 710043China School of Aerospace Engineering Tsinghua UniversityBeijing 100084China

This paper proposes an optimal,robust,and efficient guidance scheme for the perturbed minimum-time low-thrust transfer toward the geostationary *** Earth’s oblateness perturbation and shadow are taken into *** is difficult for a Lyapunov-based or trajectory-tracking guidance method to possess multiple characteristics at the same time,including high guidance optimality,robustness,and onboard computational *** this work,a concise relationship between the minimum-time transfer problem with orbital averaging and its optimal solution is identified,which reveals that the five averaged initial costates that dominate the optimal thrust direction can be approximately determined by only four initial modified equinoctial orbit elements after a coordinate *** on this relationship,the optimal averaged trajectories constituting the training dataset are randomly generated around a nominal averaged *** polynomial regression models are trained on the training dataset and are regarded as the costate *** the transfer,the spacecraft can obtain the real-time approximate optimal thrust direction by combining the costate estimations provided by the estimators with the current state at any ***,all these computations onboard are *** simulation results show that the proposed guidance scheme possesses extremely high guidance optimality,robustness,and onboard computational efficiency.

关键词： Low thrust Orbital transfer Trajectory optimization Guidance Indirect method Orbital averaging Machine learning Geostationary satellites

路面谱随机激励下的轮式发射系统动力学建模与仿真

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Acta Mechanica Sinica 2024年第5期40卷 161-174页

作者：伍根洋芮筱亭王国平江民王勋 Institute of Launch dynamics Nanjing University of Science and Technology Nanjing China National Key Laboratory of Complex Multibody System dynamics Nanjing China

轮式发射系统行驶动力学建模与仿真是其动力学性能和试验设计的前提和基础,日益提高的轮式发射系统动态性能迫切需要一种快速高效的大型多体系统动力学计算方法。本文采用多体系统传递矩阵法建立了轮式发射系统的动力学模型,给出了相应... 详细信息

轮式发射系统行驶动力学建模与仿真是其动力学性能和试验设计的前提和基础,日益提高的轮式发射系统动态性能迫切需要一种快速高效的大型多体系统动力学计算方法。本文采用多体系统传递矩阵法建立了轮式发射系统的动力学模型,给出了相应的拓扑图和动力学方程,此外,通过快速傅里叶逆变换重构了平行车轮的路面不平度,结合蒙特卡罗方法对随机路面激励下轮式发射系统的动力学特性进行了模拟和讨论分析结果表明,随着路面不平度级别和行驶速度的增加,轮式发射系统的振动加速度幅值越大,在正常车速下,路面激励对车体的影响远大于车速。模态试验和行驶试验验证了动力学建模和仿真的正确性本文可拓展到其他包含概率不确定性的多体系统动力学建模和分析.

关键词：路面不平度行驶速度多体系统动力学加速度幅值路面激励行驶试验随机激励路面谱

An innovative inertial parameters identification method for non-cooperative space targets based on electrostatic interaction

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Chinese Journal of Aeronautics 2024年第9期37卷 417-432页

作者： Heng JING Zixuan ZHENG Deja CHE Jianping YUAN National Key Laboratory of Aerospace Flight dynamics Northwestern Polytechnical UniversityXi'an 710072China School of Astronautics Northwestern Polytechnical UniversityXi'an 710072China

Inertial characteristics of non-cooperative targets are crucial for space capture and sub-sequent on-orbit *** methods for identifying inertial parameters involve proximity operations,which are associated with the risk of collision with non-cooperative *** paper introduces a long-range,contactless method for identifying the inertial parameters of a non-cooperative target during the pre-capture ***,electrostatic interaction is used as an external excitation to alter the target's motion.A force estimation algorithm that uses measure-ments from visual and potential sensors is proposed to estimate the electrostatic interaction and eliminate the need for force ***,a recursive estimation-identification framework is presented to concurrently estimate the coupled motion state,weak electrostatic interaction,and inertial parameters of the *** simulation results show that the proposed method extends the identification distance to 170 times that of the previous method while maintaining high identifica-tion precision forall parameters.

关键词： Non-cooperative target Inertial parameters identification Electrostatic interaction Force estimation Dynamical coupling

Impact damage testing based on high-speed continuous water jet aircraft coatings

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Chinese Journal of Aeronautics 2024年第10期37卷 249-264页

作者： Minggong SHA Ying SUN Yutong LI Yiming LIU Gregory FEDOTENKOV Lev RABINSKIY Arseniy BABAYTSEV Yulong LI School of Civil Aviation Northwestern Polytechnical UniversityXi’an 710072China Joint International Research Laboratory of Impact dynamics and Engineering Application Xi’an 710072China Shaanxi Impact dynamics and Engineering Application Laboratory Xi’an 710072China NPU Yangzi River Delta Research Institute Suzhou 215400China Moscow Aviation Institute(National Research University) Moscow 125993Russia

When an aircraft passes through a rainy area at high speed,the coating on the front edge of the fuselage will be continuously eroded by raindrops,causing the coating to wear,crack or even peel *** paper uses carbon fiber T300 material as the base material,and at the different impact speeds and impact numbers,water cutting equipment was used to simulate the erosion of the coating caused by the continuous impact of water *** damage morphology of samples at different damage stages was observed by digital microscope and Scanning Electron Microscope(SEM),and the damage evolution curve was established to analyze and reveal the damage behavior and damage mechanism of rain *** results show that the degree of damage experienced an increasing trend with the increase of impact numbers and speed,until circular peel damage was formed;no damage occurred during the incubation period,and the curvature of the damage evolution curve increased significantly after the expansion period and eventually showed a stable expansion *** mechanical properties of the coating material were the main influencing factors of its rain corrosion ***,the axially symmetric unsteady contact problem of droplets impacting the surface of a solid deformable body was *** the contact area was determined based on the iterative algorithm boundary positioning method.A mathematical model and closed mathematical formula describing the unsteady interaction between a droplet and a solid deformable obstacle were proposed.

关键词： Rain erosion damage Liquid-solid impact Multiple jets Composite materials Impact dynamics

Temperature-Dependent Tearing Behavior of Rubber Materials:Characterization and Modeling

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Acta Mechanica Solida Sinica 2024年第2期37卷 316-326页

作者： Qinyuan Yao Feilong Zhang Pan Dong Ziyuan Zhao Yi He Weiguo Li Liming Chen State Key Laboratory of Coal Mine Disaster dynamics and Control Chongqing UniversityChongqing400044China College of Aerospace Engineering Chongqing UniversityChongqing400044China

With the increasingly widespread application of rubber in many fields,there is a growing demand for quantitative characterization of temperature-dependent mechanical properties in high-temperature service *** critical tearing energy is an important criterion for determining whether rubber materials will experience tearing instability,while tear strength is a key parameter for rubber materials to resist *** is necessary to quantitatively characterize their evolution with *** theoretical research mainly relies on fitting a large amount of experimental data,which is not convenient for engineering ***,in this work,a temperature-dependent critical tearing energy model is firstly developed based on the force-heat equivalence energy density *** model considers the equivalent relationship between the critical tearing energy required for crack instability propagation and the thermal energy stored in the rubber *** is demonstrated that our model has higher prediction accuracy when compared to other ***,combining with the Griffith fracture theory,temperature-dependent tear strength models applicable to three different crack modes are separately *** models are validated using experimental data for Mode I opening cracks and ModeⅢtearing cracks,and good consistency is ***,a quantitative analysis of the influence of elastic modulus on tear strength at different temperatures is *** work provides a reliable way for predicting temperature-dependent tearing instability behavior and offers beneficial suggestions for improving the tear strength of rubber materials at different temperatures.

关键词： Temperature-dependent Critical tearing energy Tear strength Rubber Theoretical model

Seedling dynamics differ between canopy species and understory species in a tropical seasonal rainforest,SW China

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Plant Diversity 2024年第5期46卷 671-677页

作者： Libing Pan Xiaoyang Song Wenfu Zhang Jie Yang Min Cao CAS Key Laboratory of Tropical forest Ecology Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesMenglunMengla 666303YunnanChina College of Life Sciences University of Chinese Academy of SciencesBeijing 100049China

We used 11 years of census data from 450 seedling quadrats established in a 20-ha forest dynamics plot to study seedling dynamics in tree species of a tropical seasonal rainforest in Xishuangbanna,southwestern *** found that overall seedling recruitment rate and relative growth rate were higher in the rainy season than in the dry *** the recruitment rate of seedlings from canopy tree species(two species)and the relative growth rate of seedlings from understory species(nine species)were higher in the rainy season than in the dry ***,in the rainy season,the recruitment rate of seedlings was higher for canopy tree species than for understory tree *** addition,relative growth rate of seedlings was higher in the canopy species than in understory seedlings in the dry *** also observed that,in both rainy and dry seasons,mortality rate of seedlings was higher for canopy species than for understory ***,canopy tree species appear to have evolved a flexible strategy to adapt to the seasonal changes of a monsoon *** contrast,understory tree species seem to have adopted a conservative ***,these species mainly release seedlings in the rainy season and maintain relatively stable populations with a lower mortality rate and recruitment rate in both dry and rainy *** study suggests that canopy and understory seedling populations growing in forest understory may respond to future climate change scenarios with distinct regeneration strategies.

关键词： Tropical forest Tree seedling Seasonality Recruitment Mortality Relative growth rate

The dry-hot feedback between soil moisture and atmosphere and the accelerated global warming

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Science China Earth Sciences 2024年第3期67卷 890-891页

作者： Tianjun ZHOU State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid dynamics(LASG) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China

Greenhouse gas (GHG) emissions have been increasing due to human activities since the Industrial Revolution, resulting in continuous warming of the global climate system and significant drought over a large parts of global land, both have shown a non-linear growth trend in recent decades(Berg et al., 2017;Zhou et al., 2019;IPCC, 2021).

关键词： warming moisture drought