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A learning-based control pipeline for generic motor skills for quadruped robots

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第6期25卷 443-454页

作者： Yecheng shao Yongbin JIN Zhilong HUANG Hongtao WANG wei yang Center for X-Mechanics Zhejiang UniversityHangzhou310027China ZJU-Hangzhou Global Scientific and Technological Innovation Center Hangzhou311200China State Key Laboratory of Fluid Power&Mechatronic Systems Zhejiang UniversityHangzhou310058China Institute of Applied Mechanics Zhejiang UniversityHangzhou310027China

Performing diverse motor skills with a universal controller has been a longstanding challenge for legged *** motion imitation-based reinforcement learning(RL)has shown remarkable performance in reproducing designed motor skills,the trained controller is only suitable for one specific type of *** synthesis has been well developed to generate a variety of different motions for character animation,but those motions only contain kinematic information and cannot be used for *** this study,we introduce a control pipeline combining motion synthesis and motion imitation-based RL for generic motor *** design an animation state machine to synthesize motion from various sources and feed the generated kinematic reference trajectory to the RL controller as part of the *** the proposed method,we show that a single policy is able to learn various motor skills ***,we notice the ability of the policy to uncover the correlations lurking behind the reference motions to improve control *** analyze this ability based on the predictability of the reference trajectory and use the quantified measurements to optimize the design of the *** demonstrate the effectiveness of our method,we deploy the trained policy on hardware and,with a single control policy,the quadruped robot can perform various learned skills,including automatic gait transitions,high kick,and forward jump.

关键词： Quadruped robot Reinforcement learning(RL) Motion synthesis Control

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Deciphering gastric inflammation-induced tumorigenesis through multi-omics data and AI methods

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Cancer Biology & Medicine 2024年第4期21卷 312-330页

作者： Qian Zhang Mingran yang Peng Zhang Bowen Wu Xiaosen wei shao Li Institute for TCM-X MOE Key Laboratory of BioinformaticsBioinformatics DivisionBNRISTDepartment of AutomationTsinghua UniversityBeijing 100084China

Gastric cancer(GC), the fifth most common cancer globally, remains the leading cause of cancer deaths worldwide. Inflammation-induced tumorigenesis is the predominant process in GC development;therefore, systematic research in this area should improve understanding of the biological mechanisms that initiate GC development and promote cancer hallmarks. Here, we summarize biological knowledge regarding gastric inflammation-induced tumorigenesis, and characterize the multi-omics data and systems biology methods for investigating GC development. Of note, we highlight pioneering studies in multi-omics data and state-of-the-art network-based algorithms used for dissecting the features of gastric inflammation-induced tumorigenesis, and we propose translational applications in early GC warning biomarkers and precise treatment strategies. This review offers integrative insights for GC research, with the goal of paving the way to novel paradigms for GC precision oncology and prevention.

关键词： Gastric cancer inflammation-induced tumorigenesis multi-omics artificial intelligence network-based methods

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Aerial target threat assessment based on gated recurrent unit and self-attention mechanism

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Journal of Systems Engineering and Electronics 2024年第2期35卷 361-373页

作者： CHEN Chen QUAN wei shao Zhuang School of Automation Beijing Institute of TechnologyBeijing 100081China State Key Laboratory of Intelligent Control and Decision of Complex Systems Beijing 100081China

Aerial threat assessment is a crucial link in modern air combat, whose result counts a great deal for commanders to make decisions. With the consideration that the existing threat assessment methods have difficulties in dealing with high dimensional time series target data, a threat assessment method based on self-attention mechanism and gated recurrent unit(SAGRU) is proposed. Firstly, a threat feature system including air combat situations and capability features is established. Moreover, a data augmentation process based on fractional Fourier transform(FRFT) is applied to extract more valuable information from time series situation features. Furthermore, aiming to capture key characteristics of battlefield evolution, a bidirectional GRU and SA mechanisms are designed for enhanced ***, after the concatenation of the processed air combat situation and capability features, the target threat level will be predicted by fully connected neural layers and the softmax classifier. Finally, in order to validate this model, an air combat dataset generated by a combat simulation system is introduced for model training and testing. The comparison experiments show the proposed model has structural rationality and can perform threat assessment faster and more accurately than the other existing models based on deep learning.

关键词： target threat assessment gated recurrent unit(GRU) self-attention(SA) fractional Fourier transform(FRFT)

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Thermodynamic nature of black holes in coexistence region

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Science China(Physics,Mechanics & Astronomy) 2024年第5期67卷 27-32页

作者： shao-Wen wei Yu-Xiao Liu Lanzhou Center for Theoretical Physics Key Laboratory of Theoretical Physics of Gansu Provinceand Key Laboratory of Quantum Theory and Applications of Mo ELanzhou UniversityLanzhou 730000China Institute of Theoretical Physics&Research Center of Gravitation Lanzhou UniversityLanzhou 730000China

Studying the system state of coexistence regions will peek into to reveal microscopic interactions between different phases of a thermodynamic ***,there is no effective method to study thermodynamic nature of the coexistence black hole regions for the failure of the equation of *** at these coexistence states,in this work,we develop a general approach by introducing two new ratio *** first one is the ratio of the horizon radii of the saturated coexistence small and large black holes,and the second one measures that of the small black hole molecule number to the total molecule *** demonstrate that the first parameter can serve as an order parameter to characterize the first-order phase *** study also shows that the black hole state in the coexistence region is uniquely determined by these two introduced parameters bounded between 0 and *** results are quite significant in the analytical study of phase transition and the microscopic nature of black hole in the coexistence regions.

关键词： transition. state. thermodynamic

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Relationship between environmental evolution and human activities in the northeastern Qinghai-Xizang Plateau throughout the past millennium and its implications for the onset of the Anthropocene

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Science China Earth Sciences 2024年第11期67卷 3536-3549页

作者： yang PU Xueqiong wei Jianbao LIU Ke ZHANG Beibei LI Zhudeng wei Mengmeng ZHANG Tong HE Yanjun WANG Xiaohua shao School of Geographical Sciences Nanjing University of Information Science and Technology Key Laboratory of Alpine Ecology Institute of Tibetan Plateau Research Chinese Academy of Sciences State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and Limnology Chinese Academy of Sciences

In current research on the Anthropocene, assessing the impact of human activities via stratigraphic records of sediments and demarcating the Anthropocene epoch globally are critical scientific issues that urgently need to be addressed. The northeastern Qinghai-Xizang Plateau(QXP), where humans first settled permanently in large numbers in the QXP, has varying sedimentary environments that are extremely sensitive to human activities. In contrast to other regions of the QXP, the northeastern sector boasts a richer array of climatic and environmental reconstruction sequences. This distinctive feature renders it an exemplary locale for investigating the stratigraphic boundary of the Anthropocene. Through in-depth analysis and integration of existing paleoclimate and paleoenvironment sequences in the northeastern QXP, we draw the following conclusions:(1) Throughout the past millennium, the impact of human activities on the environment of the northeastern QXP has become increasingly significant, especially in the past 200–300 years, gradually overshadowing climatic factors.(2) Since AD 1950,multiple physicochemical indicators related to human activities in the northeastern QXP have shown exponential growth,forming a distinct peak within the past millennium and clearly depicting the global “Great Acceleration” phenomenon and its development process.(3) Intensified human activities have driven swift environmental shifts and “decoupled” the interplay between climatic variations and the ecological environment, propelling the northeastern QXP into the “Early Anthropocene”from the “Late Holocene”. On the basis of the above findings, we construct a model suitable for identifying the stratigraphic boundary of the Anthropocene in the northeastern QXP and note that since the ecological environment in the northeastern QXP has entered the “Early Anthropocene”, the climate signals of certain physicochemical indicators in sediments are gradually becoming weaker, whereas the signals of

关键词： Anthropocene Qinghai-Xizang Plateau (QXP) Climate change Environmental evolution Human activities

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A compact route for efficient production of high-purity β-Ga_(2)O_(3) powder

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Rare Metals 2024年第9期43卷 4573-4584页

作者： Xiao-wei Zhou Gao-Jie Chen Liang Xu Zhi-Jun shao Cheng yang Yong-Pan Tian Zhuo Zhao School of Metallurgical Engineering Anhui University of TechnologyMa'anshan 243032China Low-Carbon Research Institute Anhui University of TechnologyMa'anshan 243032China

The present study has proposed a compact process for the production of high-purity β-Ga_(2)O_(3)powder by simply using gallium metal and water as the raw *** process basically consists of two essential steps including hydrothermal synthesis of Ga OOH and calcination of Ga OOH for the production of the target product of β-Ga_(2)O_(3).Thermodynamic evaluation and systematic experiments were conducted for process parameter optimization.X-ray diffractometer(XRD),scanning electron microscopy(SEM),thermogravimetryDdifferential scanning calorimetry(TG-DSC)and X-ray photoelectron spectroscopy(XPS)were utilized to clarify the reaction mechanisms of the hydrothermal synthesis and transformation of Ga OOH to β-Ga_(2)O_(3)by *** analysis of the final product of β-Ga_(2)O_(3)obtained under the optimal conditions was carried out with inductively coupled plasma mass spectrometry(ICP-MS),and the results showed that the contents of the representative impurities such as Ni,Cu,In,Mn,Co,Zn and Cr are obviously lower than the requirement of 5N β-Ga_(2)O_(3)standard,exhibiting excellent application prospect of the proposed process to produce high-purity β-Ga_(2)O_(3).

关键词： β-Ga_(2)O_(3) Hydrothermal synthesis Calcination Purity Reaction mechanism

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Zokor activity promotes soil water infiltration in the Mu Us sandy land of northern Shaanxi,China

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Pedosphere 2024年第1期34卷 136-145页

作者： Miao GAN Xuchao ZHU Xueqin yang Xiaorong wei Qingyin ZHANG Tongchuan LI Ming'an shao Meixia MI Xi yang Mingyu CHEN State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Northwest A&F UniversityYangling 712100China College of Natural Resources and Environment Northwest A&F UniversityYangling 712100China State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China Henan Institute of Science and Technology Xinxiang 453003China College of Urban and Rural Construction Shanxi Agricultural UniversityJinzhong 030801China

Zokors are common subterranean rodents that inhabit agricultural fields, shrublands, and grasslands in the arid and semi-arid regions of China. Zokor burrowing activities can alter soil structure and affect soil hydrological processes;however, there are few studies regarding their effects on soil preferential flow in the Mu Us sandy land. An evaluation of the effects of zokor disturbance on their habitat and soil water is important for understanding the ecological role of zokors in the soil ecosystem of the Mu Us sandy land. A field dye-tracing experiment was conducted in the Gechougou watershed on the southeastern edge of the Mu Us sandy land to investigate the effect of zokor burrowing activity on soil preferential flow characteristics. Our results showed that the density of zokor tunnels was the highest(0.40–0.46 m m^(-2)) under 30%–50% vegetation coverage and that the tunnels were approximately 3 cm from the *** stained area ratio and stained path number were higher at sites with zokors than without zokors. Stained path widths were 10–80 and > 80 mm at zokor-harboring sites exhibiting homogeneous flow and heterogeneous finger flow, respectively. In the absence of zokors, homogeneous flow and highly interacted macropore flow were predominant. Soil water content below the zokor tunnels was higher than that above the tunnels. Moderate disturbance of soil structure by zokor activity facilitated soil water infiltration. These results enabled a better understanding of the effect of soil fauna on soil structure and hydrological processes and provided recommendations for ecological construction and renovation in arid and semi-arid regions.

关键词： eld dye-tracing experiment preferential flow soil fauna stained area ratio stained path number stained path width subterranean rodent surface tortoise crack

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Edge effect during microwave plasma chemical vapor deposition diamond-film:Multiphysics simulation and experimental verification

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International Journal of Minerals,Metallurgy and Materials 2024年第10期31卷 2287-2299页

作者： Zhiliang yang Kang An Yuchen Liu Zhijian Guo Siwu shao Jinlong Liu Junjun wei Liangxian Chen Lishu Wu Chengming Li Institute of Advanced Materials and Technology University of Science and Technology BeijingBeijing 100083China School of Mechanical and Materials Engineering North China University of TechnologyBeijing 100144China Shunde Innovation School University of Science and Technology BeijingFoshan 528399China National Key Laboratory of Solid-State Microwave Devices and Circuits The 55th Research Institute of China Electronics Technology Group CorporationNanjing 210016China

This study focused on the investigation of the edge effect of diamond films deposited by microwave plasma chemical vapor *** bulge height△h is a factor that affects the edge effect,and it was used to simulate plasma and guide the diamond-film deposition ***-element software COMSOL Multiphysics was used to construct a multiphysics(electromagnetic,plasma,and fluid heat transfer fields)coupling model based on electron collision *** spectroscopy and scanning electron microscopy were performed to characterize the experimental growth and validate the *** simulation results reflected the experimental trends *** discharge at the edge of the substrate accelerated due to the increase in△h(△h=0-3 mm),and the values of electron density(n_(c)),molar concentration of H(C_(H)),and molar concentration of CH_(3)(C_(CH_(3)))doubled at the edge(for the special concave sample with△h=−1 mm,the active chemical groups exhibited a decreased molar concentration at the edge of the substrate).At=0-3 mm,a high diamond growth rate and a large diamond grain size were observed at the edge of the substrate,and their values increased *** uniformity of film thickness decreased *** Raman spectra of all samples revealed the first-order characteristic peak of dia-mond near 1332 cm^(−1).When△h=−1 mm,tensile stress occurred in all regions of the ***△h=1-3 mm,all areas in the film ex-hibited compressive stress.

关键词： microwave plasma chemical vapor deposition edge discharge plasma diamond film

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Macroscopic model and statistical model to characterize electromagnetic information of a digital coding metasurface

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National Science Review 2024年第3期11卷 159-171页

作者： Rui Wen shao Jun wei Wu Zheng Xing Wang Hui Xu Han Qing yang Qiang Cheng Tie Jun Cui Institute of Electromagnetic Space Southeast University State Key Laboratory of Millimeter Waves Southeast University Peng Cheng Laboratory Pazhou Laboratory(Huangpu)

A digital coding metasurface is a platform connecting the digital space and electromagnetic wave space, and has therefore gained much attention due to its intriguing value in reshaping wireless channels and realizing new communication architectures. Correspondingly, there is an urgent need for electromagnetic information theory that reveals the upper limit of communication capacity and supports the accurate design of metasurface-based communication systems. To this end, we propose a macroscopic model and a statistical model of the digital coding metasurface. The macroscopic model uniformly accommodates both digital and electromagnetic aspects of the meta-atoms and predicts all possible scattered fields of the digital coding metasurface based on a small number of simulations or measurements. Full-wave simulations and experimental results show that the macroscopic model is feasible and accurate. A statistical model is further proposed to correlate the mutual coupling between meta-atoms with covariance and to calculate the entropy of the equivalent currents of digital coding metasurface. These two models can help reconfigurable intelligent surfaces achieve more accurate beamforming and channel estimation, and thus improve signal power and coverage. Moreover, the models will encourage the creation of a precoding codebook in metasurface-based direct digital modulation systems, with the aim of approaching the upper limit of channel capacity. With these two models, the concepts of current space and current entropy, as well as the analysis of information loss from the coding space to wave space, is established for the first time, helping to bridge the gap between the digital world and the physical world, and advancing developments of electromagnetic information theory and new-architecture wireless systems.

关键词： electromagnetic information theory current entropy current space digital coding metasurface macroscopic model statistical model

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Highly strengthening and toughening biomimetic ceramic structures fabricated via a novel coaxially printing

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Journal of Advanced Ceramics 2024年第4期13卷 403-412页

作者： Kunkun Song Shengda yang Ningqi shao Yantang Zhao Peng He Yongfeng wei Hengzhong Fan Yongsheng Zhang Qiangqiang Zhang State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China School of Civil Engineering and Mechanics Lanzhou UniversityLanzhou 730000China Key Laboratory of Mechanics on Disaster and Environment in Western China(Lanzhou University) Ministry of EducationLanzhou 730000.China

Additive manufacturing technology,by manipulating and emulating inherent multiscale,multi-material,and multifunctional structures found in nature,has created new opportunities for constructing heterogeneous structures associated with special properties and achieving ultra-high mechanical performance and reliability in ceramic composite *** this study,we have developed an innovative fabrication method designated as coaxial 3D printing for the synchronous construction of two constituents into ceramic composites with a tooth enamel biomimetic ***,the stiff silicate and flexible epoxy served as a strengthening bridge and toughening layer,*** method differed from the traditional approach of randomly dispersing reinforcing components within a ceramic *** allowed for the direct creation of an internally effective three-dimensional reinforcement network structure in ceramic *** process facilitated synergistic deformation and simultaneous enhancement of multiple materials and hierarchical *** to the uniform distribution of internal stress and effective block of microcrack propagation,the biomimetically structured silicate/epoxy ceramic composite has demonstrated much significant enhancement in mechanical properties,includingcompressive strength(48.8±3.12MPa),flexuralstrength(10.39±1.23MPa),andflexuraltoughness(218.7±54.6kJ/m^(3)),which was 0.5,2.1,and 47.5 times as high as those of the intrinsic brittle silicate ceramics,***-situ characterization and multiscale finite element simulation of microstructural evolution during three-point bending deformation further validated multiple-step features of the fracture process(silicate bridge fracture,interface detachment,epoxy extraction,and rupture),which benefited from interpenetrating structural features achieved by coaxial printing to accomplish with the complex propagating routines of the crack deflection in silicate ceramic *** coaxia

关键词： coaxial 3D printing silicate ceramic composites enamel biomimetic microstructure strengthening bridge tougheninglayer crackdeflection

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