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Modelling the formation and dissolution behavior of alumina agglomerate in the cryolite

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Particuology 2024年第3期86卷 211-222页

作者： Jiaqi Wang mao Li Benjun Cheng Hesong Li School of Energy Science and Engineering Central South UniversityChangsha410083China

The presence of alumina agglomerates seriously affects the current efficiency of the aluminum electrolysis process.Clarify the dynamic dissolution process of agglomerates is essential to improve the current efficiency of aluminum electrolysis.A mathematical model is proposed to describe the different phenomena from the formation until complete dissolution of agglomerates.Considering permeation and solidification processes of cryolite,a semi-analytical mathematical model is developed to formulate the formation,melting and dissolution processes of agglomerates,and the time duration for each stage is deduced.Porosity and heat mass transfer of agglomerates are explored based on the packing theory and mechanism of heat mass transfer in wet porous media.Dimensionless approach is applied to investigate the main factors affecting the dissolution stages and porosity of agglomerates.The results show that the superheat has a great influence on the formation and melting stage,the diameter of agglomerates can reach 14.93 mm for 200 particles agglomerated.The density decreases with the increase of agglomerated particle number,which varies in the range of 2.27-2.28 g/cm^(3).The average dissolution rate of agglomerates is about 1.83×10^(-5)-2.95×10^(-5) kg/s within the range of alumina concentration in this study.

关键词： Mathematical model Alumina agglomerate Porous media Packing theory Heatand mass transfer

A framework of force of information influence and application for C4KISR system

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Journal of Systems Engineering and Electronics 2024年第2期35卷 430-443页

作者： mao Shaojie DIAO Lianwang SUN Yu WANG Heng YI Kan XU Xin mao Xiaobin ZHANG Kecheng SHENG Long Science and Technology on Information Systems Engineering Laboratory The 28th Research Institute of China Electronics Technology Group CorporationNanjing 210007China Unit 94860 of the PLA Nanjing 210008China

The subversive nature of information war lies not only in the information itself, but also in the circulation and application of information. It has always been a challenge to quantitatively analyze the function and effect of information flow through command, control, communications, computer, kill, intelligence,surveillance, reconnaissance (C4KISR) system. In this work, we propose a framework of force of information influence and the methods for calculating the force of information influence between C4KISR nodes of sensing, intelligence processing,decision making and fire attack. Specifically, the basic concept of force of information influence between nodes in C4KISR system is formally proposed and its mathematical definition is provided. Then, based on the information entropy theory, the model of force of information influence between C4KISR system nodes is constructed. Finally, the simulation experiments have been performed under an air defense and attack scenario. The experimental results show that, with the proposed force of information influence framework, we can effectively evaluate the contribution of information circulation through different C4KISR system nodes to the corresponding tasks. Our framework of force of information influence can also serve as an effective tool for the design and dynamic reconfiguration of C4KISR system architecture.

关键词： information warfare command control communications computer kill intelligence surveillance reconnaissance(C4KISR)system information circulation force of information influence information entropy

Probabilistic-Ellipsoid Hybrid Reliability Multi-Material Topology Optimization Method Based on Stress Constraint

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 757-792页

作者： Zibin mao Qinghai Zhao Liang Zhang College of Mechanical and Electrical Engineering Qingdao UniversityQingdao266071China National Engineering Research Center for Intelligent Electrical Vehicle Power System Qingdao UniversityQingdao266071China

This paper proposes a multi-material topology optimization method based on the hybrid reliability of the probability-ellipsoid model with stress constraint for the stochastic uncertainty and epistemic uncertainty of mechanical loads in optimization design.The probabilistic model is combined with the ellipsoidal model to describe the uncertainty of mechanical loads.The topology optimization formula is combined with the ordered solid isotropic material with penalization(ordered-SIMP)multi-material interpolation model.The stresses of all elements are integrated into a global stress measurement that approximates the maximum stress using the normalized p-norm function.Furthermore,the sequential optimization and reliability assessment(SORA)is applied to transform the original uncertainty optimization problem into an equivalent deterministic topology optimization(DTO)problem.Stochastic response surface and sparse grid technique are combined with SORA to get accurate information on the most probable failure point(MPP).In each cycle,the equivalent topology optimization formula is updated according to the MPP information obtained in the previous cycle.The adjoint variable method is used for deriving the sensitivity of the stress constraint and the moving asymptote method(MMA)is used to update design variables.Finally,the validity and feasibility of the method are verified by the numerical example of L-shape beam design,T-shape structure design,steering knuckle,and 3D T-shaped beam.

关键词： Stress constraint probabilistic-ellipsoid hybrid topology optimization reliability analysis multi-material design

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高电感永磁同步风力发电机的设计和分析

太阳能学报 2011年第6期32卷 907-912页

作者：茆美琴黄荣赓喻莉合肥工业大学教育部光伏系统工程研究中心合肥230009

根据新型的基于电流源型风力发电系统的要求,采用分数槽集中绕组设计了输出功率为10kW的高电感永磁同步发电机,并运用有限元法分析了电机在不同负载情况下的工作特性。分析结果表明,电机的齿槽转矩较小,电机绕组的感应电动势接近正弦,... 详细信息

根据新型的基于电流源型风力发电系统的要求,采用分数槽集中绕组设计了输出功率为10kW的高电感永磁同步发电机,并运用有限元法分析了电机在不同负载情况下的工作特性。分析结果表明,电机的齿槽转矩较小,电机绕组的感应电动势接近正弦,在一定的风速范围内,电机输出的电流经整流器整流以后,其直流电流波动小,满足电流型风力发电系统控制要求。

关键词：永磁同步发电机高电感风力有限元

基于PIR控制器的CSC-DPMSG-WGS低电压穿越控制

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电力系统自动化 2017年第14期41卷 153-158页

作者：张榴晨吴文晗茆美琴合肥工业大学教育部光伏系统工程研究中心安徽省合肥市230009

提出了一种基于比例—积分—谐振(PIR)控制器,且适用于电流源型永磁直驱风力发电系统(CSC-DPMSG-WGS)的低电压穿越运行控制方案。根据所提出的方法,电网故障时,通过机侧变换器控制来限制风力发电机的电磁功率,以实现机侧和网侧的功率平... 详细信息

提出了一种基于比例—积分—谐振(PIR)控制器,且适用于电流源型永磁直驱风力发电系统(CSC-DPMSG-WGS)的低电压穿越运行控制方案。根据所提出的方法,电网故障时,通过机侧变换器控制来限制风力发电机的电磁功率,以实现机侧和网侧的功率平衡;网侧控制器在正序旋转坐标系下采用PIR控制器同时对正负序电流进行无差控制,以消除两倍基频的功率波动,进而稳定直流电流。仿真与实验结果表明,所提出的控制方案在电网对称及不对称故障下均可有效降低直流电流波动,并实现电流源型永磁直驱风力发电系统的低电压穿越。

关键词：电流源型变换器谐振控制器功率波动低电压穿越

BSEC Method for Unveiling Open Clusters and its Application to Gaia DR3:83 New Clusters

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Research in Astronomy and Astrophysics 2024年第5期24卷 169-184页

作者： Zhong-Mu Li Cai-Yan mao Institute of Astronomy and Information Dali UniversityDali 671003China

Open clusters(OCs) are common in the Milky Way, but most of them remain undiscovered. There are numerous techniques, including some machine-learning algorithms, available for the exploration of OCs. However, each method has its limitations and therefore, different approaches to discovering OCs hold significant values. We develop a comprehensive approach method to automatically explore the data space and identify potential OC candidates with relatively reliable membership determination. This approach combines the techniques of Hierarchical Density-Based Spatial Clustering of Applications with Noise, Gaussian mixture model, and a novel cluster member identification technique, color excess constraint. The new method exhibits efficiency in detecting OCs while ensuring precise determination of cluster memberships. Because the main feature of this technique is to add an extra constraint(EC) for the members of cluster candidates using the homogeneity of color excess,compared to typical blind search codes, it is called Blind Search-Extra Constraint(BSEC) method. It is successfully applied to the Gaia Data Release 3, and 83 new OCs are found, whose color–magnitude diagrams(CMDs) are fitted well to the isochrones. In addition, this study reports 621 new OC candidates with discernible main sequence or red giant branch. It is shown that BSEC technique can discard some false negatives of previous works, which takes about three percentage of known clusters. It shows that as an EC, the color excess(or twocolor) constraint is useful for removing fake cluster member stars from the clusters that are identified from the positions and proper motions of stars, and getting more precise CMDs, when differential reddening of member stars of a cluster is not large(e.g., ΔE(GBP-GRP) < 0.5 mag). It makes the CMDs of 15% clusters clearer(in particular for the region near turnoff) and therefore is helpful for CMD and stellar population studies. Our result suggests that the color excess constraint is more appropriate for clusters with small di

关键词： Galaxy stellar content-(Galaxy:)open clusters and associations general-stars fundamental parameters

Simulation of RFI Cancellation Using Subspace Projection Algorithm for PAF Receiver

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Research in Astronomy and Astrophysics 2024年第1期24卷 237-244页

作者： Peng Wu Jian Li mao-Zheng Chen Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China University of Chinese Academy of Sciences Beijing 100049China Xinjiang Key Laboratory of Microwave Technology Urumqi 830011China

The simulation of radio frequency interference(RFI) cancellation by applying a spatial filtering technique for phased array feed(PAF) is presented. In order to better reflect the characteristics of PAF, a new signal model is to add the coupling coefficient among elements of PAF to the conventional array signal model. Then the subspace projection(SP) algorithm is used to cancel RFI from the correlation matrix of the signal, and finally, the 2D power image is drawn. The power variation of signal-of-interest direction and RFI direction before and after using the SP algorithm is analyzed. The new signal model and simulation strategy can be used to test and verify the beamformer.

关键词： methods:analytical techniques:radar astronomy telescopes

The combination of gut microbiota-depleted treatment and fecal microbiota transplantation is an important strategy to verify the efficacy of Traditional Chinese Medicine though modulation of gut dysbiosis

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Journal of Traditional Chinese Medicine 2024年第1期44卷 222-223页

作者： XING Yunqi LI Junxiang YUAN Yali mao Tangyou Gastroenterology Department Dongfang HospitalBeijing University of Chinese MedicineBeijing 100078China Department of Hepatology Yueyang Hospital of Integrated Traditional Chinese and Western MedicineShanghai University of Traditional Chinese MedicineShanghai 201203China

To the Editors:We read with great interest the study recently published by Sun et al 1 entitled“Electroacupuncture at Tianshu(ST25)and Zusanli(ST36)alleviates stress-induced irritable bowel syndrome in mice by modulating gut microbiota and corticotropin-releasing factor”in which the microbial details of electroacupuncture(EA)-induced protection in irritable bowel syndrome(IBS)were investigated.

关键词： releasing treatment details

Single image defogging via multi-exposure image fusion and detail enhancement

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Journal of Safety Science and Resilience 2024年第1期5卷 37-46页

作者： Wenjing mao Dezhi Zheng Minze Chen Juqiang Chen School of Information and Electronics Advanced Research Institute of Multidisciplinary ScienceBeijing Institute of TechnologyBeijing100081China Chinese Aeronautical Establishment Beijing100012China

Outdoor cameras play an important role in monitoring security and social governance.As a common weather phenomenon,haze can easily affect the quality of camera shooting,resulting in loss and distortion of image details.This paper proposes an improved multi-exposure image fusion defogging technique based on the artificial multi-exposure image fusion(AMEF)algorithm.First,the foggy image is adaptively exposed,and the fused image is subsequently obtained via multiple exposures.The fusion weight is determined by the saturation,contrast,and brightness.Finally,the image fused by a multi-scale Laplacian algorithm is enhanced with simple adaptive details to obtain a clearer defogging image.It is subjectively and objectively verified that this algorithm can obtain more image details and distinct picture colors without a priori information,effectively improving the defogging ability.

关键词： Image defogging Multi-scale fusion Laplacian pyramid Adaptive detail enhancement