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Sampling-efficient path planning and improved actor-critic-based obstacle avoidance for autonomous robots

Science China(Information Sciences) 2024年第5期67卷 197-214页

作者： Yefeng yang Tao HUANG Tianqi WANG wenyu yang Han CHEN Boyang LI Chih-yung wen Department of Aeronautical and Aviation Engineering The Hong Kong Polytechnic University Center for Control Theory and Guidance Technology Harbin Institute of Technology School of Engineering The University of Newcastle Research Center for Unmanned Autonomous Systems The Hong Kong Polytechnic University

Autonomous robots have garnered extensive utilization in diverse fields. Among the critical concerns for autonomous systems, path planning holds paramount importance. Notwithstanding considerable efforts in its development over the years, path planning for autonomous systems continues to grapple with challenges related to low planning efficiency and inadequate obstacle avoidance response in a timely *** study proposes a novel and systematic solution to the path planning problem within intricate office buildings. The solution consists of a global planner and a local planner. To handle the global planning aspect, an adaptive clustering-based dynamic programming rapidly exploring random tree(ACDP-RRT) algorithm is proposed. ACDP-RRT effectively identifies obstacles on the map by leveraging geometric *** obstacles are then represented as a collection of sequentially arranged convex polygons, optimizing the sampling region and significantly enhancing sampling efficiency. For local planning, a network decoupling actor-critic(ND-AC) algorithm is employed. The proposed ND-AC simplifies the local planner design process by integrating planning and control loops into a neural network(NN) trained via an end-to-end model-free deep reinforcement learning(DRL) framework. Moreover, the adoption of network decoupling(ND) techniques leads to an improved obstacle avoidance success rate when compared to conventional actor-critic(AC)-based methods. Extensive simulations and experiments are conducted to demonstrate the effectiveness and robustness of the proposed approach.

关键词： rapidly exploring random tree (RRT) adaptive clustering network decoupling actor critic (AC) path planning

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MPI/OpenMP-Based Parallel Solver for Imprint Forming Simulation

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 461-483页

作者： yang Li Jiangping Xu Yun Liu wen Zhong Fei Wang School of Mechanical Engineering Jiangsu UniversityZhenjiang212016China School of Mechanical Engineering Wuhan Polytechnic UniversityWuhan430023China Shenyang Mint Company Limited Shenyang110092China

In this research,we present the pure open multi-processing(OpenMP),pure message passing interface(MPI),and hybrid MPI/OpenMP parallel solvers within the dynamic explicit central difference algorithm for the coining process to address the challenge of capturing fine relief features of approximately 50 *** such precision demands the utilization of at least 7 million tetrahedron elements,surpassing the capabilities of traditional serial programs previously *** mitigate data races when calculating internal forces,intermediate arrays are introduced within the OpenMP *** helps ensure proper synchronization and avoid conflicts during parallel ***,in the MPI implementation,the coins are partitioned into the desired number of *** division allows for efficient distribution of computational tasks across multiple *** simulation examples are conducted to compare the three solvers with serial programs,evaluating correctness,acceleration ratio,and parallel *** results reveal a relative error of approximately 0.3%in forming force among the parallel and serial solvers,while the predicted insufficient material zones align with experimental ***,speedup ratio and parallel efficiency are assessed for the coining process *** pureMPI parallel solver achieves a maximum acceleration of 9.5 on a single computer(utilizing 12 cores)and the hybrid solver exhibits a speedup ratio of 136 in a cluster(using 6 compute nodes and 12 cores per compute node),showing the strong scalability of the hybrid MPI/OpenMP programming *** approach effectively meets the simulation requirements for commemorative coins with intricate relief patterns.

关键词： Hybrid MPI/OpenMP parallel computing MPI OpenMP imprint forming

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Advances in functional coatings on biliary stents

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Regenerative Biomaterials 2024年第2期3卷 55-75页

作者： Kaining yang wenxin Sun Lanyue Cui Yuhong Zou Cuie wen Rongchang Zeng Department of Bioengineering College of Chemical and Biological EngineeringShandong University of Science and TechnologyQingdao 266590China Corrosion Laboratory for Light Metals College of Materials Science and EngineeringShandong University of Science and TechnologyQingdao 266590China school of Engineering RMIT UniversityMelbourneVIC3001Australia

Biliary stenting is an important interventional method for the prevention and treatment of biliary tract ***,complications,such as postoperative biliary infection and re-stenosis,frequently occur due to the extensive scope of the biliary system and the complex composition of *** com-bination of coating technology and biliary stents is expected to bring new approaches to the solution of these *** cutting-edge advance on functional coatings on biliary stents is reviewed from seven perspectives:anticorrosion,-bacterial,-tumor,stone-dissolving,X-ray visibility,anti-stent migration and functional composite *** de-velopment trend is also *** performance of the numerous functional coatings for various purposes is generally up to expectations,but the balance between the medica tions'effectiveness and their safety needs to be further *** contemporary investigations have advanced to the leve of animal experiments,offering crucial fundamental assurance for broader human *** combination of biliary stent and functional coatings is an innovative idea with great potential for future development.

关键词： biliary stent coating anticorrosion antibacterial antitumor stone-dissolving X-ray visibility antistent migration

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Topology optimization of chiral metamaterials with application to underwater sound insulation

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Applied Mathematics and Mechanics(English Edition) 2024年第7期45卷 1119-1138页

作者： Chao WANG Honggang ZHAO yang WANG Jie ZHONG Dianlong YU Jihong wen Laboratory of Science and Technology on Integrated Logistics Support National University of Defense Technology

Chiral metamaterials have been proven to possess many appealing mechanical phenomena, such as negative Poisson's ratio, high-impact resistance, and energy absorption. This work extends the applications of chiral metamaterials to underwater sound insulation. Various chiral metamaterials with low acoustic impedance and proper stiffness are inversely designed using the topology optimization scheme. Low acoustic impedance enables the metamaterials to have a high and broadband sound transmission loss(STL), while proper stiffness guarantees its robust acoustic performance under a hydrostatic pressure. As proof-of-concept demonstrations, two specimens are fabricated and tested in a water-filled impedance tube. Experimental results show that, on average, over 95% incident sound energy can be isolated by the specimens in a broad frequency range from 1 k Hz to 5 k Hz, while the sound insulation performance keeps stable under a certain hydrostatic pressure. This work may provide new insights for chiral metamaterials into the underwater applications with sound insulation.

关键词： chiral metamaterial topology optimization underwater sound insulation low acoustic impedance sound transmission loss (STL) O427.5 74J20

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Effect of Sc on Al_(3)Fe phase and mechanical properties of as-cast AA5052 aluminum alloy

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China Foundry 2024年第3期21卷 257-264页

作者： yang Li Qing Yu Feng-feng Chen Jia-wen He Hong-mei yang Meng-nie Li Faculty of Materials Science and Engineering Kunming University of Science and TechnologyKunming 650093China

The AA5052 aluminum alloy is widely used in automobile and aerospace manufacturing,and with the development of light-weight alloys,it is required that these materials exhibit better mechanical *** studies have demonstrated that the addition of Sc to aluminum alloys can improve both the microstructure and properties of the *** this study,the effect of Sc on the Fe-rich phase and properties of the AA5052 aluminum alloy was studied by adding 0%,0.05%,0.2%,and 0.3%*** results show that with the increase of Sc,the coarse needle-like Fe-rich phase gradually transforms into Chinese-script and then nearly spherical particles,reduce the size of Fe-rich phase,and refine the grain with increase of high angle grain boundaries(HAGBs).These microstructure changes enhance the strength of the AA5052 alloy through Sc *** ductility of the alloy is obviously improved because the addition of a lower amount of Sc changes the morphology of Fe-rich phase from needle-like into a Chinese-script,and it is subsequently reduced as a result of significant increase in HAGBs with increasing Sc content.

关键词： AA5052 aluminum alloy Al3Fe phase mechanical properties grain boundary

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The centrosymmetric to non-centrosymmetric transformation induced by alkaline-earth cations producing infrared nonlinear optical AeMn6Ga6S16（Ae = Ca, Sr）

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Science China Chemistry 2024年第9期67卷 2941-2948页

作者： yang-Ping Zhang Shao-Min Pei wen-Fa Chen Bin-wen Liu Xiao-Ming Jiang Guo-Cong Guo State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter Chinese Academy of Sciences School of Physical Science and Technology Shanghai Tech University Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China

Non-centrosymmetric（NCS） structure is an indispensable prerequisite for second-order nonlinear optical（NLO） ***, the mainstream approach for designing new NCS structures still relies on chemical substitution, necessitating an urgent infusion of fresh ideas. In this work, two isomorphic sulfides AeMn6Ga6S16（Ae = Ca, 1; Sr, 2） are afforded by modifying the skeleton of centrosymmetric（CS） Mn2Ga2S5via introducing strong electropositive alkaline-earth cations. Concretely, the incorporation of Ca2+/Sr2+cations allows the elementary [MnGaS9]∞chains to reconfigure into bumpy [MnS6]-[GaS4] layers in a new engagement manner, thus enabling the conversion from CS to NCS structure. Such modifications cause not only strong second-harmonic generation（SHG） responses（～1.5 × benchmark AgGaS2@1,700 nm）, but also significantly feasible bandgaps（2.60–2.64 e V） compared to the sulfide Mn2Ga2S5（1.36 e V）, which ultimately facilitate ultrahigh laser-induced damage thresholds（4.4–6.6 × AgGaS2@1,064 nm for compounds 1 and 2）. The present study offers an ingenious approach for the transformation of CS to NCS structure.

关键词： second-harmonic generation non-centrosymmetrical structure NLO functional motif solid-state method

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Residue Based Open-Loop Modal Analysis Method for Detecting LFMR of PMSG-WFs Penetrated Power Systems

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CSEE Journal of Power and Energy Systems 2024年第4期10卷 1454-1465页

作者： Luonan Qiu Tianhao wen yang Liu Q.H.Wu School of Electric Power Engineering South China University of TechnologyGuangzhou510640China

This paper proposes a residue based open-loop modal analysis method to detect low frequency modal resonance(LFMR),including asymmetric low frequency modal attraction(ALFMA)and asymmetric low frequency modal repulsion(ALFMR),of permanent magnetic synchronous generator based wind farms(PMSG-WFs)penetrated power *** formation of ALFMA and ALFMR caused by two open-loop low frequency oscillation(LFO)modes moving close and apart is analyzed in *** predicting the trajectories of closed-loop LFO modes based on calculation of residue of open-loop LFO modes,both ALFMA and ALFMR can be *** proposed method can select LFO modes which move to the right half complex plane as control parameters *** studies are carried out on a three-machine power system and a four-machine 11-bus power system to verify the properties of the proposed method.

关键词： Asymmetric low frequency modal attraction asymmetric low frequency modal repulsion low frequency modal resonance residue based open-loop modal analysis method

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Different effects of 24 dietary intakes on gastroesophageal reflux disease: A mendelian randomization

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World Journal of Clinical Cases 2024年第14期12卷 2370-2381页

作者： Yu-Xin Liu wen-Tao yang yang Li Department of Oncology Hospital of Chengdu University of Traditional Chinese MedicineChengdu 610072Sichuan ProvinceChina Department of Cardiovascular Chengdu Integrated TCM&Western Medicine HospitalChengdu 610041Sichuan ProvinceChina Department of Nuclear Medicine Hospital of Chengdu University of Traditional Chinese MedicineChengdu 610072Sichuan ProvinceChina

BACKGROUND In observational studies,dietary intakes are associated with gastroesophageal re-flux disease(GERD).AIM To conduct a two-sample mendelian randomization(MR)analysis to determine whether those associations are *** To explore the relationship between dietary intake and the risk of GERD,we extracted appropriate single nucleotide polymorphisms from genome-wide asso-ciation study data on 24 dietary *** methods were adopted for data analysis:Inverse variance weighting,weighted median methods,and MR-Egger's *** odds ratio(OR)and 95%confidence interval(CI)were used to eva-luate the causal association between dietary intake and *** Our univariate Mendelian randomization(UVMR)results showed significant evidence that pork intake(OR,2.83;95%CI:1.76-4.55;P=1.84×10–5),beer intake(OR,2.70,95%CI:2.00-3.64;P=6.54×10–11),non-oily fish intake(OR,2.41;95%CI:1.49-3.91;P=3.59×10–4)have a protective effect on *** addition,dried fruit intake(OR,0.37;95%CI:0.27-0.50;6.27×10–11),red wine intake(OR,0.34;95%CI:0.25-0.47;P=1.90×10-11),cheese intake(OR,0.46;95%CI:0.39-0.55;P=3.73×10-19),bread intake(OR,0.72;95%CI:0.56-0.92;P=0.0009)and cereal intake(OR,0.45;95%CI:0.36-0.57;P=2.07×10-11)were negatively associated with the risk of *** was a suggestive asso-ciation for genetically predicted coffee intake(OR per one SD increase,1.22,95%CI:1.03-1.44;P=0.019).Multi-variate Mendelian randomization further confirmed that dried fruit intake,red wine intake,cheese intake,and cereal intake directly affected *** contrast,the impact of pork intake,beer intake,non-oily fish intake,and bread intake on GERD was partly driven by the common risk factors for ***,after adjusting for all four elements,there was no longer a suggestive association between coffee intake and *** This study provides MR evidence to support the causal relationship between a broad range of dietary intake and GERD,providing new insights for the treatment and p

关键词： Dietary Gastroesophageal reflux disease Mendelian randomization Disease management Randomized controlled trial

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Asymptotic normality of error density estimator in stationary and explosive autoregressive models

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Applied Mathematics(A Journal of Chinese Universities) 2024年第1期39卷 140-158页

作者： WU Shi-peng yang wen-zhi GAO Min HU Shu-he School of Mathematical Sciences&School of Big Data and Statistics Anhui UniversityHefei 230601China School of Statistics Shanxi University of Finance and EconomicsTaiyuan030006China

In this paper,we consider the limit distribution of the error density function estima-tor in the rst-order autoregressive models with negatively associated and positively associated random *** mild regularity assumptions,some asymptotic normality results of the residual density estimator are obtained when the autoregressive models are stationary process and explosive *** order to illustrate these results,some simulations such as con dence intervals and mean integrated square errors are provided in this *** shows that the residual density estimator can replace the density\estimator"which contains errors.

关键词： explosive autoregressive models residual density estimator asymptotic distribution association sequence

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ZnO/ZnS heterostructure in N-doped porous carbon for anchoring-diffusion-conversion of polysulfides for high-performance lithium-sulfur batteries

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Rare Metals 2024年第8期43卷 3661-3676页

作者： Fei Wang Rong-Wei Huang wen-Chang Han Chun-Man yang wen-Hao yang Peng Dong Chao-Ling Wu Yi-Yong Zhang Xue Li Ying-Jie Zhang National Local Joint Engineering Research Center for LithiumIon Batteries and Materials Preparation Technology Key Laboratory of Advanced Batteries Materials of Yunnan ProvinceFaculty of Metallurgical and Energy Engineering Kunming University of Science and Technology Engineering Research Center of Alternative Energy Materials and Devices Sichuan UniversityMinistry of Education

The shuttle effect of polysulfides is one of the key factors hindering the commercialization of lithiumsulfur batteries（LSBs）.Owing to their high conductivity and advantageous structure,heterostructures can be used in sulfur fixation and catalysis of *** this study,a flower-shaped ZnO/ZnS heterostructure on a nitrogendoped porous carbon（NPC） sulfur host was *** ZnO/ZnS heterostructure regulates the electronic structure of the material and exhibits higher metal-like ***,the ZnO/ZnS heterostructure combines the strong adsorption property of ZnO and the high catalytic ability of ZnS to realize the anchoring-diffusionconversion of lithium poly sulfides（LiPSs）.Results reveal that the developed ZnO/ZnS@NPC/S cathode has excellent electrochemical performance in LSBs,achieving a high discharge specific capacity of 1365.3 mAh·g-1at 0.1C and excellent rate capability(719 mAh·g-1at 2C;the capacity decay rate is only 0.042% per cycle after 1000 cycles).Even under a high sulfur loading-E/S（electrolyte/sulfur）ratio of 5.1 mg·cm-2-6 μl·mg-1,a high specific capacity of 723.7 mAh·g-1is maintained after 60 *** study provides a new strategy for a multifunctional sulfur host that can effectively alleviate the shuttle effect of LiPSs and improve the utilization of sulfur active substances.

关键词： ZnO/ZnS heterostructure Lithium–sulfur batteries Density functional theory Anchor Conversion

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