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Dynamic motion of quadrupedal robots on challenging terrain:a kinodynamic optimization approach

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Frontiers of Mechanical Engineering 2024年第3期19卷 23-40页

作者： qi li Lei DING Xin LUO Engineering Research Center of Hubei Province for Clothing Information Wuhan 430200China School of Computer Science and Artificial Intelligence Wuhan Textile UniversityWuhan 430200China State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China

The dynamic motion of quadrupedal robots on challenging terrain generally requires elaborate spatial–temporal kinodynamic motion planning and accurate control at higher refresh rate in comparison with regular ***,conventional quadrupedal robots usually generate relatively coarse planning and employ motion replanning or reactive strategies to handle terrain *** resultant complex and computation-intensive controller may lead to nonoptimal motions or the breaking of locomotion *** this paper,a kinodynamic optimization approach is *** generate long-horizon optimal predictions of the kinematic and dynamic behavior of the quadruped robot on challenging terrain,we formulate motion planning as an optimization problem;jointly treat the foot’s locations,contact forces,and torso motions as decision variables;combine smooth motion and minimal energy consumption as the objective function;and explicitly represent feasible foothold region and friction constraints based on terrain *** track the generated motions accurately and stably,we employ a whole-body controller to compute reference position and velocity commands,which are fed forward to joint controllers of the robot’s *** verify the effectiveness of the developed approach through simulation and on a physical quadruped robot *** show that the quadruped robot can successfully traverse a 30°slope and 43% of nominal leg length high step while maintaining the rhythm of dynamic trot gait.

关键词： quadrupedal robot kinodynamic planning nonlinear optimization challenging terrain whole-body control

One-shot Face Reenactment with Dense Correspondence Estimation

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Machine Intelligence Research 2024年第5期21卷 941-953页

作者： Yunfan liu qi li Zhenan Sun School of Artificial Intelligence University of Chinese Academy of SciencesBeijing100049China Center for Research on Intelligent Perception and Computing Institute of AutomationChinese Academy of SciencesBeijing100190China

One-shot face reenactment is a challenging task due to the identity mismatch between source and driving *** existing methods fail to completely eliminate the interference of driving subjects’identity information,which may lead to face shape distortion and undermine the realism of reenactment *** solve this problem,in this paper,we propose using a 3D morphable model(3DMM)for explicit facial semantic decomposition and identity *** of using 3D coefficients alone for reenactment control,we take advantage of the generative ability of 3DMM to render textured face *** proxies contain abundant yet compact geometric and semantic information of human faces,which enables us to compute the face motion field between source and driving images by estimating the dense *** this way,we can approximate reenactment results by warping source images according to the motion field,and a generative adversarial network(GAN)is adopted to further improve the visual quality of warping *** experiments on various datasets demonstrate the advantages of the proposed method over existing state-of-the-art benchmarks in both identity preservation and reenactment fulfillment.

关键词： Generative adversarial networks face image manipulation face image synthesis face reenactment 3D morphable model

Characteristics and Genesis of Acid Drainage Contamination from a Rock Tunneling Project Site

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Journal of Earth Science 2024年第1期35卷 190-200页

作者： Yanyun li Zejiao Luo Shihua qi Hubei Key Laboratory of Yangtze River Basin Environmental Aquatic Science School of Environmental StudiesChina University of GeosciencesWuhan 430078China State Key Laboratory of Biogeology and Environmental Geology China University of GeosciencesWuhan 430078China

While acid mine drainage(AMD)issues have become a topic of global concern,few studies have focused on acid drainage problems of non-mining *** conducted field research and a series of laboratory experiments to investigate the characteristics,release processes and formation of acid drainage *** rock samples and adjacent surface water,groundwater,soil and sediment samples were collected at a railway tunnel construction site in central China,and various parameters,such as the p H,mineral ion concentrations,and heavy metal concentrations,were *** on the measured concentrations,surface water and sediments were seriously contaminated by acids,sulfate salts and heavy *** in surface water showed a decreasing tendency as the distance from the spoils increased,while that in sediments showed a greater influence of coprecipitation and adsorption processes of heavy metal *** eluviation experiments of three rock samples indicated that R2(silty fine sandstone)was the most likely major acid drainage *** ferrooxidans was cultured and isolated from contaminated water to study the oxidation conditions during the release *** significant release of acid drainage when air and bacteria were both in the culture container suggested that oxygen and bacteria were necessary to produce acid drainage from spoils.

关键词： acid mine drainage heavy metals leaching oxidation

Multistage guidance on the diffusion model inspired by human artists’ creative thinking

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Frontiers of Information Technology & Electronic Engineering 2024年第1期25卷 170-178页

作者： Wang qi Huanghuang DENG Taihao li AI Research Institute Zhejiang LabHangzhou 311121China Department of Computer Science and Technology Zhejiang UniversityHangzhou 310027China

Current research on text-conditional image generation shows parallel performance with ordinary painters but still has much room for improvement when compared to that of artist-ability paintings,which usually represent multilevel semantics by gathering features ofmultiple objects into one *** a preliminary experiment,we confirm this and then seek the opinions of three groups of individuals with varying levels of art appreciation ability to determine the distinctions that exist between painters and *** then use these opinions to improve an artificial intelligence(AI)painting system from painter-level image generation toward artistic-level image generation.

关键词： gathering ordinary artist

Photoswitchable Spiropyridine Enabled Photoactuation of Polymeric Hydrogels under Physiological pH Conditions

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Chinese Journal of Polymer Science 2024年第10期42卷 1602-1609页

作者： Cong liao Meng-qi Du Chuang li Key Laboratory of Precision and Intelligent Chemistry Department of Polymer Science and Engineering University of Science and Technology of China

The incorporation of molecular switches into polymer networks has been a powerful approach for the development of functional polymer materials that display macroscopic actuation and function enabled directly by molecular changes. However, such materials sometimes require harsh conditions to perform their functions, and the design of new molecular photoswitches that can function under physiological conditions is highly needed. Here, we report the design and synthesis of a spiropyridine-based photoswitchable hydrogel that exhibits light-driven actuation at physiological pH. Owing to its high p Ka, spiropyridine maintains its ring-open protonated form at neutral pH, and the resulting hydrogel remains in a swollen state. Upon irradiation with visible light, the ring closure of spiropyridine leads to a decrease in the charge and a reduction in the volume of the hydrogel. The contracted gel could spontaneously recover to its expanding state in the dark, and this process is highly dynamic and reversible when the light is switched on and off. Furthermore, the hydrogel shows switchable fluorescence in response to visible light. Bending deformation is observed in the hydrogel thin films upon irradiation from one side. Importantly, the independence of this spiropyridine hydrogel from the acidic environment makes it biotolerant and shows excellent biocompatibility. This biocompatible spiropyridine hydrogel might have important biorelated applications in the future.

关键词： Biocompatibility Photoactuation Physiological pH Polymer hydrogel Spiropyridine photowitch

Recursive Filtering for Stochastic Systems With Filter-and-Forward Successive Relays

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IEEE/CAA Journal of Automatica Sinica 2024年第5期11卷 1202-1212页

作者： Hailong Tan Bo Shen qi li hongjian liu School of Mathematics-Physics and Finance Anhui Polytechnic UniversityWuhu 241000China Anhui Future Technology Research Institute Anhui Polytechnic UniversityWuhu 241000China College of Information Science and Technology Donghua UniversityShanghai 201620China Engineering Research Center of Digitalized Textile and Fashion Technology Ministry of EducationShanghai 201620China School of Information Science and Engineering Hangzhou Normal UniversityHangzhou 311121China

In this paper,the recursive filtering problem is considered for stochastic systems over filter-and-forward successive relay(FFSR)*** FFSR is located between the sensor and the remote filter to forward the *** the successive relay,two cooperative relay nodes are adopted to forward the signals alternatively,thereby existing switching characteristics and inter-relay interferences(IRI).Since the filter-and-forward scheme is employed,the signal received by the relay is retransmitted after it passes through a linear *** objective of the paper is to concurrently design optimal recursive filters for FFSR and stochastic systems against switching characteristics and IRI of ***,a uniform measurement model is proposed by analyzing the transmission mechanism of ***,novel filter structures with switching parameters are constructed for both FFSR and stochastic *** the help of the inductive method,filtering error covariances are presented in the form of coupled difference ***,the desired filter gain matrices are further obtained by minimizing the trace of filtering error ***,the stability performance of the filtering algorithm is analyzed where the uniform bound is guaranteed on the filtering error ***,the effectiveness of the proposed filtering method over FFSR is verified by a three-order resistance-inductance-capacitance circuit system.

关键词： filtering successive stochastic

Analyzing the spatiotemporal evolution and driving forces of gross ecosystem product in the upper reaches of the Chaobai River Basin

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Frontiers of Environmental Science & Engineering 2024年第8期18卷 117-132页

作者： Jiacheng li qi Han liqiu Zhang li Feng Guihuan liu Beijing Key Laboratory for Source Control Technology of Water Pollution College of Environmental Science and EngineeringBeijing Forestry UniversityBeijing 100083China Engineering Research Center for Water Pollution Source Control&Eco-remediation College of Environmental Science and EngineeringBeijing Forestry UniversityBeijing 100083China Center of Eco-compensation Chinese Academy of Environmental PlanningMinistry of Ecology of EnvironmentBeijing 100041China

The Chaobai River Basin,which is a crucial ecological barrier and primary water source area within the Beijing-Tianjin-Hebei region,possesses substantial ecological *** gross ecosystem product(GEP)in the Chaobai River Basin is a reflection of ecosystem conditions and quantifies nature’s contributions to humanity,which provides a basis for basin ecosystem service management and *** study investigated the spatiotemporal evolution of GEP in the upper Chaobai River Basin and explored the driving factors influencing GEP spatial *** patterns from 2005 to 2020 were analyzed,and GEP was calculated for 2005,2010,2015,and *** driving factors influencing GEP spatial differentiation were identified using the optimal parameter-based geographical detector(OPGD)*** key findings are as follows:(1)From 2005 to 2020,the main ecosystem types were forest,grassland,and *** areas experienced significant changes,and conversions mainly occurred among urban,water,grassland and agricultural ecosystems.(2)Temporally,the GEP in the basin increased from 2005 to 2020,with regulation services *** the county(district)scale,GEP exhibited a north-west-high and south-east-low pattern,showing spatial differences between per-unit-area GEP and county(district)GEP,while the spatial variations in per capita GEP and county(district)GEP were similar.(3)Differences in the spatial distribution of GEP were influenced by regional natural geographical and socioeconomic *** these factors,gross domestic product,population density,and land-use degree density contributed *** among different driving forces noticeably impacted GEP spatial *** findings underscore the necessity of incorporating factors such as population density and the intensity of land-use development into ecosystem management decision-making processes in the upper reaches of the Chaobai River *** policies

关键词： Ecosystem pattern Gross ecosystem product(GEP) Spatiotemporal evolution Optimal parameter-based geographical detector(OPGD) Chaobai River Basin

Wettability and corrosion behavior between alkaline slag from sodium smelting of vanadium-titanium magnetite and refractory substrates

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Journal of Iron and Steel Research International 2024年第6期31卷 1399-1410页

作者： Fei Zhao Zhi-wei Bian hong-xin Zhao De-sheng Chen Zhang-fu Yuan Yu-lan Zhen li-na Wang Tao qi Collaborative Innovation Center of Steel Technology University of Science and Technology BeijingBeijing 100083China National Engineering Research Center of Green Recycling for Strategic Metal Resources Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China Hebei Zhongke Tongchuang Vanadium&Titanium Technology Co. Ltd.Hengshui 053000HeheiChina

The sodium smelting of vanadium-titanium magnetite can achieve the comprehensive utilization of Fe,V,and ***,the generation of alkaline slag during this process may cause damage to refractory *** wettability and corrosion behavior of alkaline slag on three types of refractory(MgO-C,SiC,and high alumina refractory)substrates were investigated at temperatures up to 1200℃.The effects of duration on the wettability of molten slag on SiC substrates were also *** showed that the high alumina refractory exhibited better wettability with the molten slag than the others,and thus,it is easier to be *** results of scanning electron microscopy coupled with energy dispersive spectroscopy showed that MgO-C and high alumina refractory substrates were severely *** was a visible and regular interfacial reaction layer between the slag and SiC refractory substrate,which was produced by the redox reaction between the metal oxides in the slag and the SiC refractory *** the increase in holding time,the interface layer expands and silico-ferrite phases are generated at the *** redox reaction between Fe_(2)O_(3) and SiC substrate is the main reason for the *** comparing the differences in wettability and corrosion behavior between the alkaline slag from sodium smelting of vanadium-titanium magnetite and MgO-C,SiC and high alumina refractories,it is concluded that SiC refractory has good corrosion resistance to the *** oxides in the slag accelerate the oxidation rate of SiC refractory.

关键词： Wettability Corrosion Alkaline slag-Contact angle Vanadium-titanium magnetite Refractory

Visual experimental study of nanofluids application to promote CO_(2) absorption in a bubble column

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Chinese Journal of Chemical Engineering 2024年第3期67卷 228-237页

作者： Shangyuan Cheng Guisheng qi Yuliang li Yixuan Yang Shanxi Province Key Laboratory of Higee-Oriented Chemical Engineering North University of ChinaTaiyuan 030051China

The addition of dispersed-phase nanoparticles in the liquid phase can enhance the gas-liquid transfer process as the suspended nanoparticles affect the transfer process inside the fluid through microdisturbance or micro-convection *** this article,a high-speed digital camera was used to visualize the bubble behavior of CO_(2) in pure water and nanofluids to examine the effects of CO_(2) gas flow rate,nanoparticle solid content and type on the bubble behavior in the *** CO_(2) absorption performance in three water-based nanofluids were compared in a *** the mass transfer characteristics during CO_(2) bubble absorption and the reasons for the enhanced gas-liquid mass transfer effect of nanoparticles were *** results showed that the presence of nanoparticles affected the formation process of bubbles in the fluid,shortened the bubble detachment time,reduced the detachment diameter,effectively increased the gas-liquid contact area,and improved the bubbles detachment *** system with MCM-41 corresponded to a higher overall mass transfer *** MCM-41 contained surfactant that enhanced foaming behavior in *** prevented the transfer of CO_(2) to some extent,and the CO_(2) absorption by uncalined MCM-41/H_(2)O was 5.34%higher than that by pure *** with SiO_(2) nanoparticles with the same particle size and the same composition,MCM-41 had a higher adsorption capacity and better hydrophilicity due to its larger specific surface area and rich porous structure,which was more favorable to accelerate the collision between nanoparticles and CO_(2) bubbles to cause *** the condition of 0.1%(mass)solid content,the enhancement of CO_(2) absorption process by MCM-41 nanoparticles was more significant and improved by 16.9%compared with pure water.

关键词： Nanofluids CO_(2) absorption Mass transfer MCM-41 Bubble column