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Reducing Subspaces of Toeplitz Operators Induced by a Class of Non-analytic Monomials over the Unit Ball

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Acta Mathematica Sinica,English Series 2024年第7期40卷 1767-1777页

作者： Yan Yue SHI Bo ZHANG xu TANG Yu feng LU School of Mathematical Sciences Ocean University of ChinaQingdao 266100P.R.China School of Mathematics and Information Sciences Yantai UniversityYantai 264005P.R.China School of Mathematical Sciences Space Engineering UniversityBeijing 101416P.R.China School of Mathematical Sciences Dalian University of TechnologyDalian 116024P.R.China

In this paper,we describe the minimal reducing subspaces of Toeplitz operators induced by non-analytic monomials on the weighted Bergman spaces and Dirichlet spaces over the unit ball B_(2).It is proved that each minimal reducing subspace M is finite dimensional,and if dim M≥3,then M is induced by a ***,the structure of commutant algebra v(T_(w)N_(z)N):={M^(*)_(w)NM_(z)N,M^(*)_(z)NM_(w)N}′is determined by N and the two dimensional minimal reducing subspaces of(T_(w)N_(z)*** also give some interesting examples.

关键词： Reducing subspace operator-weighted shifts Toeplitz operator von Neumann algebra

The Adjustment Analysis Method of the Active Surface Antenna Based on Convolutional Neural Network

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Research in Astronomy and Astrophysics 2024年第6期24卷 294-306页

作者： You Ban Shang Shi Na Wang Qian xu Shufei feng School of Mechanical Engineering Xinjiang UniversityUrumqi 830017China Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China School of Mechanical Engineering Dongguan University of TechnologyDongguan 523808China

Active surface technique is one of the key technologies to ensure the reflector accuracy of the millimeter/submillimeter wave large reflector *** antenna is complex,large-scale,and high-precision equipment,and its active surfaces are affected by various factors that are difficult to comprehensively deal *** this paper,based on the advantage of the deep learning method that can be improved through data learning,we propose the active adjustment value analysis method of large reflector antenna based on deep *** method constructs a neural network model for antenna active adjustment analysis in view of the fact that a large reflector antenna consists of multiple panels spliced *** on the constraint that a single actuator has to support multiple panels(usually 4),an autonomously learned neural network emphasis layer module is designed to enhance the adaptability of the active adjustment neural network *** classical 8-meter antenna is used as a case study,the actuators have a mean adjustment error of 0.00252 mm,and the corresponding antenna surface error is0.00523 *** active adjustment result shows the effectiveness of the method in this paper.

关键词： techniques:radar astronomy telescopes methods:analytical methods:numerical

A disk I/O optimized system for concurrent graph processing jobs

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Frontiers of Computer Science 2024年第3期18卷 13-29页

作者： Xianghao xu Fang WANG Hong JIANG Yongli CHENG Dan feng Peng FANG School of Computer Science and Engineering Nanjing University of Science and TechnologyNanjing 210094China Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China Department of Computer Science&Engineering University of Texas at ArlingtonArlingtonTX 76019USA College of Computer and Data Science Fuzhou UniversityFuzhou 350108China Zhejiang Lab Hangzhou 311121China

In order to analyze and process the large graphs with high cost efficiency,researchers have developed a number of out-of-core graph processing systems in recent years based on just one commodity *** the other hand,with the rapidly growing need of analyzing graphs in the real-world,graph processing systems have to efficiently handle massive concurrent graph processing(CGP)***,due to the inherent design for single graph processing job,existing out-of-core graph processing systems usually incur unnecessary data accesses and severe competition of I/O bandwidth when handling the CGP *** this paper,we propose GraphCP,a disk I/O optimized out-of-core graph processing system that efficiently supports the processing of CGP *** proposes a benefit-aware sharing execution model to share the I/O access and processing of graph data among the CGP jobs and adaptively schedule the graph data loading based on the states of vertices,which efficiently overcomes above challenges faced by existing out-of-core graph processing ***,GraphCP adopts a dependency-based future-vertex updating model so as to reduce disk I/Os in the future *** addition,GraphCP organizes the graph data with a Source-Sorted Sub-Block graph representation for better processing capacity and I/O access *** evaluation results show that GraphCP is 20.5×and 8.9×faster than two out-of-core graph processing systems GridGraph and GraphZ,and 3.5×and 1.7×faster than two state-of-art concurrent graph processing systems Seraph and GraphSO.

关键词： graph processing disk I/O concurrent jobs

Automatic Miscalibration Detection and Correction of LiDAR and Camera Using Motion Cues

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 318-329页

作者： Pai Peng Dawei Pi Guodong Yin Yan Wang Liwei xu Jiwei feng School of Mechanical Engineering Southeast UniversityNanjing 211102China School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210014China School of Mechanical and Aerospace Engineering Nanyang Technological UniversitySingaporeSingapore

This paper aims to develop an automatic miscalibration detection and correction framework to maintain accurate calibration of LiDAR and camera for autonomous vehicle after the sensor ***,a monitoring algorithm that can continuously detect the miscalibration in each frame is designed,leveraging the rotational motion each individual sensor ***,as sensor drift occurs,the projection constraints between visual feature points and LiDAR 3-D points are used to compute the scaled camera motion,which is further utilized to align the drifted LiDAR scan with the camera ***,the proposed method is sufficiently compared with two representative approaches in the online experiments with varying levels of random drift,then the method is further extended to the offline calibration experiment and is demonstrated by a comparison with two existing benchmark methods.

关键词： Autonomous vehicle LiDAR and camera Miscalibration detection and correction Sensor drift

Policy Network-Based Dual-Agent Deep Reinforcement Learning for Multi-Resource Task Offloading in Multi-Access Edge Cloud Networks

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China Communications 2024年第4期21卷 53-73页

作者： feng Chuan Zhang xu Han Pengchao Ma Tianchun Gong Xiaoxue School of Communications and Information Engineering Chongqing University of Posts and TelecommunicationsChongqing 400065China Institute of Intelligent Communication and Network Security Chongqing University of Posts and TelecommunicationsChongqing 400065China Key Laboratory of Big Data Intelligent Computing Chongqing University of Posts and TelecommunicationsChongqing 400065China School of Information Engineering Guangdong University of TechnologyGuangzhou 510006China

The Multi-access Edge Cloud(MEC) networks extend cloud computing services and capabilities to the edge of the networks. By bringing computation and storage capabilities closer to end-users and connected devices, MEC networks can support a wide range of applications. MEC networks can also leverage various types of resources, including computation resources, network resources, radio resources,and location-based resources, to provide multidimensional resources for intelligent applications in 5/***, tasks generated by users often consist of multiple subtasks that require different types of resources. It is a challenging problem to offload multiresource task requests to the edge cloud aiming at maximizing benefits due to the heterogeneity of resources provided by devices. To address this issue,we mathematically model the task requests with multiple subtasks. Then, the problem of task offloading of multi-resource task requests is proved to be NP-hard. Furthermore, we propose a novel Dual-Agent Deep Reinforcement Learning algorithm with Node First and Link features(NF_L_DA_DRL) based on the policy network, to optimize the benefits generated by offloading multi-resource task requests in MEC networks. Finally, simulation results show that the proposed algorithm can effectively improve the benefit of task offloading with higher resource utilization compared with baseline algorithms.

关键词： benefit maximization deep reinforcement learning multi-access edge cloud task offloading

Effect of phase transition during roasting of Mountain Pass rare earth concentrate on leaching efficiency of rare earths

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Journal of Rare Earths 2024年第2期42卷 409-414,I0006页

作者： Yanyan Zhao xu Sun Deliang Meng Xiangsheng Liu Qiang Zhong Zongyu feng National Engineering Research Center for Rare Earth Grirem Advanced Materials Co.Ltd.Beijing0088China Rare Earth Functional Materials(Xiong'an)Innovation Center Co. Ltd.Xiongan071700China General Research Institute for Nonferrous Metals Beijing100088China

To find a greener and more economical approach for treating the Mountain Pass rare earth concentrate(MPREC),a novel "Combination Method",including the processes of oxidizing roasting,HCI leaching and sulfuric acid roasting,is proposed in this *** this paper,the effect of phase transition behavior in hydrochloric acid leaching during oxidative roasting at 450-600℃ was *** roasting,the bastnasite in MPREC is decomposed into CeLa_(2)O_(3)F_(3) and(Ce_(0.33),La_(0.33),Ca_(0.33))O_(1.5).As the CeLa_(2)O_(3)F_(3) phase has the fluorine-fixation effect,the generated CeLa_(2)O_(3)F_(3) phase can not be dissolved by HCI after roasting at 500 and 550℃,but it can be decomposed by HCI after roasting at over 600℃,resulting in the improvement of the leaching rate of total F *** maximum leaching efficiency of rare earth elements(REEs) can reach 70.32 wt% at the roasting temperature of 550℃.After roasting at over 600℃,some F^-ions in the solution combined with RE^(3+) to form REF_(3) precipitate and enter the leaching residue,and the others are in the form of [CeF_(3)]^+ in the leaching solution during leaching,therefore,the leaching efficiency of non-ce rium REEs decreases while that of cerium element *** work provides basic research for optimizing the actual production process of MPREC.

关键词： Mountain pass rare earth mine Roasting Phase change Rare earths

Enhancing the mechanical properties of casting eutectic high -entropy alloys via W addition

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International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1364-1372页

作者： xu Yang Dezhi Chen Li feng Gang Qin Shiping Wu Ruirun Chen National Key Laboratory for Precision Hot Processing of Metals School of Material Science and EngineeringHarbin Institute of TechnologyHarbin 150001China

The effect of W element on the microstructure evolution and mechanical properties of Al_(1.25)CoCrFeNi3 eutectic high-entropy alloy and Al_(1.25)CoCrFeNi_(3-x)W_(x)(x=0,0.05,0.1,0.3,and 0.5;atomic ratio)high-entropy alloys(HEAs)were *** show that the Al_(1.25)CoCrFeNi_(3-x)W_(x) HEAs are composed of face-centered cubic and body-centered cubic(BCC)*** W content increases,the microstructure changes from eutectic to *** addition of W lowers the nucleation barrier of the BCC phase,decreases the valence electron concentration of the HEAs,and replaces Al in the BCC phase,thus facilitating the nucleation of the BCC *** results show that the addition of W greatly improves the mechanical properties,and solid-solution,heterogeneous-interface,and second-phase strengthening are the main strengthening *** yield strength,tensile strength,and elongation of the Al_(1.25)CoCrFeNi2.95W0.05 HEA are 601.44 MPa,1132.26 MPa,and 15.94%,respectively,realizing a balance between strength and *** fracture mode of the Al_(1.25)CoCrFeNi_(3-x)W_(x) HEAs is ductile–brittle mixed fracture,and the crack propagates and initiates in the BCC *** eutectic lamellar structure impedes crack propagation and maintains plasticity.

关键词： high-entropy alloy microstructure mechanical property fracture behavior

Simulation and analysis of soil homogenization drills based on discrete element method and response surface methodology

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Particuology 2024年第5期88卷 128-148页

作者： Zhipeng Wang Tong Zhu Youzhao Wang Song Yang feng Ma xu Li Institute of Process Equipment and Environmental Engineering School of Mechanical Engineering and AutomationNortheastern UniversityShenyang110819China Liaoning Coning Testing Co. Ltd.Shenyang110170 China

Currently,rotary drilling is one of the main pieces of equipment used for in-situ remediation of contaminated ***,this equipment has problems such as uneven mixing and low utilization efficiency,which affect the efficiency of in-situ soil *** improve the efficiency of in-situ soil remediation,this paper takes contaminated black soil as the research object,and the structural design of the new three-stage soil remediation auger is carried out based on *** mixing process of soil and heavy metal passivator under different motion and structural parameters was investigated by the discrete element method(DEM)and response surface *** experimental design was based on rotational speed,homogenizing mixing time,crushing section pitch,and homogenizing section pitch as factors,and soil fragmentation ratio,the coefficient of dispersion,and torque as optimization *** kinematic and structural parameters of the three-stage auger drill bit were then optimized using the one-factor method,the orthogonal test,and the response surface methodology,*** test method uses a one-way test to determine the central level value of the orthogonal test and a comprehensive balance method to determine the best combination of parameters for the orthogonal test,which is then used as the central value of the response surface test for parameter *** optimal combinations of kinematic and structural parameters of the three-stage auger drill bit are determined and validated using response surface *** optimum combination of parameters was found to be a speed of 129 rpm,a homogenizing mixing time of 24 s,a pitch of 165 mm in the crushing section,and a pitch of 132 mm in the homogenizing *** error between the optimal value of the predicted model using the response surface method and the actual simulated value under the optimal parameters is 4.2%,4.9%,and 5.3%,*** optimized factor parameters provide a refe

关键词： Black soil Mixing homogeneity Orthogonal method Response surface methodology Discrete element method Soil remediation

Mechanism of internal thermal runaway propagation in blade batteries

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Journal of Energy Chemistry 2024年第2期89卷 184-194,I0005页

作者： xuning feng Fangshu Zhang Wensheng Huang Yong Peng Chengshan xu Minggao Ouyang School of Vehicle and Mobility Tsinghua UniversityBeijing 100084China

Blade batteries are extensively used in electric vehicles,but unavoidable thermal runaway is an inherent threat to their safe *** study experimentally investigated the mechanism underlying thermal runaway propagation within a blade battery by using a nail to trigger thermal runaway and thermocouples to track its propagation inside a *** results showed that the internal thermal runaway could propagate for up to 272 s,which is comparable to that of a traditional battery *** velocity of the thermal runaway propagation fluctuated between 1 and 8 mm s^(-1),depending on both the electrolyte content and high-temperature gas *** the early stages of thermal runaway,the electrolyte participated in the reaction,which intensified the thermal runaway and accelerated its *** the battery temperature increased,the electrolyte evaporated,which attenuated the acceleration *** diffusion affected thermal runaway propagation through both heat transfer and mass *** experimental results indicated that gas diffusion accelerated the velocity of thermal runaway propagation by 36.84%.We used a 1D mathematical model and confirmed that convective heat transfer induced by gas diffusion increased the velocity of thermal runaway propagation by 5.46%-17.06%.Finally,the temperature rate curve was analyzed,and a three-stage mechanism for internal thermal runaway propagation was *** Stage I,convective heat transfer from electrolyte evaporation locally increased the temperature to 100℃.In Stage II,solid heat transfer locally increases the temperature to trigger thermal *** StageⅢ,thermal runaway sharply increases the local *** proposed mechanism sheds light on the internal thermal runaway propagation of blade batteries and offers valuable insights into safety considerations for future design.

关键词： Lithium-ion battery Blade battery Thermal runaway Internal thermal runaway propagation