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A revisit to the role of Mo in an MP35N superalloy:An experimental and theoretical study

Journal of Materials Science & Technology 2023年第26期157卷 60-70页

作者： Qing Cheng Jinyong Mo Xiaoqing Li xiandong xu Center for High Resolution Electron Microscopy College of Materials Science and EngineeringHunan UniversityChangsha 410082China Institute of Massive Amorphous Metal Science School of Materials Science and Physics China University of Mining and TechnologyXuzhou 221116China Department of Materials Science and Engineering Applied Materials Physics KTH-Royal Institute of TechnologyStockholm SE-10044Sweden

Molybdenum(Mo)has been recognized as an essential alloying element of the MP35N(Co_(35.4)Cr_(22.9)Ni_(35.5)Mo_(6.2),at.%)superalloy for enhancing strength and corrosion resistance.However,a full understanding of the addition of Mo on microstructure and mechanical properties of the Mo-free parent alloy is lacking.In this work,we consider five(Co_(37.7)Cr_(24.4)Ni_(37.9))_(100-x)Mo_(x)(x=0,0.7,2.0,3.2,and 6.2)alloys,and reveal that yield/tensile strength and ductility are continuously increased for these alloys with increasing Mo content while a single-phase face-centered cubic structure remains unchanged.It is found that strong solid solution strengthening(SSS)is a main domain to the improved yield strength,whereas grain boundaries are found to soften by the Mo addition.The first-principles calculations demonstrate that a severe local lattice distortion contributes to the enhanced SSS,and the grain boundary softening effect is mostly associated with the decreased shear modulus.Both first-principles calculations and scanning transmission electron microscopy observations reveal that the stacking fault energy(SFE)reduces by the Mo addition.The calculated SFE value decreases from 0.4 mJ/m^(2) to-11.8 mJ/m^(2) at 0 K as Mo content increases from 0 at.%to 6.2 at.%,and experimentally measured values of SFE at room temperature for both samples are about 18 mJ/m^(2) and 9 mJ/m^(2),respectively.The reduction of SFE promoted the generation of stacking faults and deformation twins,which sustain a high strain hardening rate,thus postponing necking instability and enhancing tensile strength and elongation.

关键词： Mo addition Solid solution strengthening Grain boundary softening Local lattice distortion First-principles simulations Stacking fault energy Deformation twin

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Multi-objective Dynamic Reconfiguration for Urban Distribution Network Considering Multi-level Switching Modes

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Journal of Modern Power Systems and Clean Energy 2022年第5期10卷 1241-1255页

作者： Hongjun Gao Wang Ma Yingmeng Xiang Zao Tang xiandong xu Hongjin Pan Fan Zhang Junyong Liu College of Electrical Engineering Sichuan UniversityChengdu 610065China Iowa State University Ameslowa50010USA Key Laboratory of Smart Gridof Ministry of Education Tianjin UniversityTianjin 300072China

The increasing integration of photovoltaic generators(PVGs) and the uneven economic development in different regions may cause the unbalanced spatial-temporal distribution of load demands in an urban distribution network(UDN). This may lead to undesired consequences, including PVG curtailment, load shedding, and equipment inefficiency, etc. Global dynamic reconfiguration provides a promising method to solve those challenges. However, the power flow transfer capabilities for different kinds of switches are diverse, and the willingness of distribution system operators(DSOs) to select them is also different. In this paper, we formulate a multi-objective dynamic reconfiguration optimization model suitable for multi-level switching modes to minimize the operation cost, load imbalance, and the PVG curtailment. The multi-level switching includes feeder-level switching, transformer-level switching, and substation-level switching. A novel load balancing index is devised to quantify the global load balancing degree at different levels. Then, a stochastic programming model based on selected scenarios is established to address the uncertainties of PVGs and loads. Afterward, the fuzzy c-means(FCMs) clustering is applied to divide the time periods of reconfiguration. Furthermore, the modified binary particle swarm optimization(BPSO)and Cplex solver are combined to solve the proposed mixed-integer second-order cone programming(MISOCP) model. Numerical results based on the 148-node and 297-node systems are obtained to validate the effectiveness of the proposed method.

关键词： Binary particle swarm optimization(BPSO) dynamic reconfiguration multi-level switching mixed-integer second-order cone programming(MISOCP) urban distribution network(UDN)

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Improved Properties in Relation to Fine Precipitate Microstructures Tailored by Combinatorial Processes in an Al-Cu-Mg-Si Alloy

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Acta Metallurgica Sinica(English Letters) 2020年第11期33卷 1527-1534页

作者： Fengjiao Niu Jianghua Chen Cuilan Wu Jing Wu xiandong xu Pan Xie Xiongwei Yu Center for High-Resolution Electron Microscopy College of Materials Science and EngineeringHunan UniversityChangsha 410082China

The 2xxx series Al alloys have been widely used in aerospace industry owing to their high strength,good plasticity and superior formability.To ensure a good control of shape,the quenched alloy sheets require a small pre-deformation before artificial aging.However,this pre-deformation considerably deteriorates the mechanical strength of the Al-3.0 Cu-1.8 Mg-0.5 Si(wt%)alloys due to the formation of unfavorable large-sized precipitates at dislocations.To tackle this issue,we designed a pre-aging process prior to the pre-deformation.The thermal-mechanical treatment,involving pre-aging,pre-deformation and subsequent aging,markedly enhanced the ultimate tensile strength up to 521 MPa compared to that(448 MPa)of the alloy without pre-aging.Microstructure characterization revealed that the fine precipitates(~2 nm)with a uniform dispersion were promoted within the Al matrix,which in turn partly suppressed the formation of the unfavorable large-sized precipitate(~100 nm).Our findings provide a new clue for designing stronger Al alloys with age-hardenability.

关键词： Aluminum alloys Thermo-mechanical treatment Precipitation Age-hardenability

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三维原子探针的电场结构模拟研究

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电子显微学报 2024年第2期43卷 173-179页

作者：李依轩刘俊亮王伟于得洋徐先东湖南大学材料科学与工程学院湖南长沙410082 中国科学院近代物理研究所甘肃兰州730000 中国科学院大学核科学与技术学院北京100049

本文针对目前世界上被广泛使用的局部电极原子探针的样品及局部电极几何结构,通过有限元方法,结合多物理场仿真技术,研究了局部电极与针状样品的距离z、样品尖端曲率半径ρ、局部电极的入口直径φ、厚度w、开口角度α和入口长度h等参数... 详细信息

本文针对目前世界上被广泛使用的局部电极原子探针的样品及局部电极几何结构,通过有限元方法,结合多物理场仿真技术,研究了局部电极与针状样品的距离z、样品尖端曲率半径ρ、局部电极的入口直径φ、厚度w、开口角度α和入口长度h等参数对样品尖端附近的局部电场的影响。模拟结果表明:当z与φ的取值满足z/φ≥1时,既能在样品尖端得到较高的蒸发电场强度,又能降低局部电极对离子轨迹的影响;局部电极的厚度w和开口角度α的取值对样品尖端的电场影响较小;增大局部电极入口长度h的值有利于提高样品尖端电场强度;随着原子的蒸发(样品尖端曲率半径ρ增大),为维持原子蒸发所需的电场强度,施加在样品上的电压V与样品尖端的曲率半径ρ成正比,且所需维持的电场强度越高,施加的电压V越大。

关键词：三维原子探针局部电极有限元模拟电场结构离子轨迹

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计及风电接入的海上油气田能源系统分层调控

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电力建设 2024年第3期45卷 69-77页

作者：李志川杨季平孙兆恒李子航刘静刘龙飞徐宪东中海油能源发展股份有限公司清洁能源分公司天津市300459 天津大学电气自动化与信息工程学院天津市300072

针对海上油气田电网对具有不确定性的海上风电的消纳难题,提出了基于燃气/燃油透平发电机与储能协同的海上油气田电网分层调控策略。首先,分析了海上油气田多能耦合特征以及含海上风电的海上油气田能源系统典型结构。在此基础上,提出了... 详细信息

针对海上油气田电网对具有不确定性的海上风电的消纳难题,提出了基于燃气/燃油透平发电机与储能协同的海上油气田电网分层调控策略。首先,分析了海上油气田多能耦合特征以及含海上风电的海上油气田能源系统典型结构。在此基础上,提出了基于日前与日内优化调度的海上油气田综合能源系统分层调度策略,以平抑海上风电小时级不确定性。进一步,提出基于饱和滤波器的快速功率分配策略,通过储能与燃气/燃油透平发电机协同平抑海上风电的分钟级和秒级不确定性。最后,通过算例分析说明,所提分层调控策略能有效降低运行成本,提升海上风电的消纳能力。

关键词：海上油气田海上风电并网风电调控分层调控优化调度

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A Data Stream Subspace Clustering Algorithm

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国际计算机前沿大会会议论文集 2015年第1期 97-99页

作者： Xiang Yu xiandong xu Liandong Lin Department of Computer Science and Technology Heilongjiang Institute of TechnologyHarbinChina Heilongjiang Province Key Lab of Senior- Education for Electronic Engineering Heilongjiang UniversityHarbinChina

The main aim of data stream subspace clustering is to find clusters in subspace in rational time accurately. The existing data stream subspace clustering algorithms are greatly influenced by parameters. Due to the flaws of traditional data stream subspace clustering algorithms, we propose SCRP, a new data stream subspace clustering algorithm. SCRP has the advantages of fast clustering and being insensitive to outliers. When data stream changes, the changes will be recorded by the data structure named Region-tree, and the corresponding statistics information will be updated. Further SCRP can regulate clustering results in time when data stream changes. According to the experiments on real datasets and synthetic datasets, SCRP is superior to the existing data stream subspace clustering algorithms on both clustering precision and clustering speed, and it has good scalability to the number of clusters and dimensions.

关键词： data mining data stream subspace clustering feature selection dimension reduction

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基于M估计算法的三维点云平面拟合方法研究

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电子测量技术 2024年第5期47卷 70-76页

作者：杨少舟龙东平陈继尧吴士旭徐先懂湖南科技大学机电工程学院湘潭411201 难加工材料高效精密加工湖南省重点实验室湘潭411201 长沙视浪科技有限公司长沙410006 韶关学院智能工程学院韶关512005

通过激光传感器获取的三维点云难免混入噪声和异常点,导致点云平面的拟合精度降低。为解决该问题,本文提出了一种结合M估计样本一致性(MSAC)算法和主成分分析(PCA)法拟合点云平面的方法。该方法首先通过MSAC算法去除点云数据中的异常点... 详细信息

通过激光传感器获取的三维点云难免混入噪声和异常点,导致点云平面的拟合精度降低。为解决该问题,本文提出了一种结合M估计样本一致性(MSAC)算法和主成分分析(PCA)法拟合点云平面的方法。该方法首先通过MSAC算法去除点云数据中的异常点,获得较为理想的点云平面,然后使用PCA方法对保留的点云数据进行平面拟合,以获取更加精确的点云平面参数。使用电池托盘作为被测物,应用3D线激光轮廓传感器扫描被测物并将点云数据传输到计算机进行处理。通过设定的仿真数据和电池托盘点云数据进行实验,发现本文方法与随机采样一致性(RANSAC)结合PCA、最小平方中值(LMedS)结合PCA的方法相比,在耗时接近的情况下,能够显著降低异常点对点云平面拟合的影响,获得更精确的平面拟合参数。对两个部分的电池托盘点云滤波处理后进行平面拟合时,能够发现本文方法与其他两种方法相比,标准差分别降低了28.6%和22.5%%、24.0%和29.0%,该方法具有较高的平面拟合精度和实用性。

关键词：点云数据异常点平面拟合 M估计主成分分析方法

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不同浓度生石灰对池塘浮游生物的影响分析

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中国农学通报 2024年第17期40卷 158-164页

作者：侯明勇陶志英陈文静徐先栋饶毅江西省水产科学研究所南昌330096

设置不同浓度的生石灰(0、50、100、150、200、250 mg/L),对江西省水产科学研究所内的常见小型池塘进行帆布围格实验,测定其对池塘碱度、pH及浮游生物物种数、生物密度和多样性的影响。结果表明:施用生石灰后水体的碱度、pH有不同程度... 详细信息

设置不同浓度的生石灰(0、50、100、150、200、250 mg/L),对江西省水产科学研究所内的常见小型池塘进行帆布围格实验,测定其对池塘碱度、pH及浮游生物物种数、生物密度和多样性的影响。结果表明:施用生石灰后水体的碱度、pH有不同程度的增加,但施用1 d后的数值大于7 d后。各组共检测到浮游植物25个属种,隶属于绿藻门15属、蓝藻门6属、硅藻门3属、隐藻门1属,其中100 mg/L处理组生物量、生物密度最大,分别为422.45 mg/L、55.901×10^(4)个/L,50 mg/L处理组多样性指数最佳。浮游动物隶属于6种属,含甲壳动物桡足类2种属、甲壳动物枝角类1种属、轮虫3种属,50 mg/L处理组生物密度、物种数、丰富度指数、香农-威纳指数均为最大,分别为1304.2个/L、5、1.3333及1.5596。综上,施用50 mg/L生石灰处理池塘水质对水体浮游生物最有利,且节约成本,可以为水产实践生石灰施用剂量提供参考。

关键词：生石灰池塘浮游生物碱度多样性

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A Study on Karyotypes and Ag-NORs of Odontobutis potamophila

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Agricultural Biotechnology 2018年第2期7卷 127-129页

作者： Haihua WANG xiandong xu Wen QIU Bin WU Zhiying TAO Shugan ZHU Jiangxi Fisheries Research Institute Nanchang 330039 Fisheries Technology Extension Center of Shangrao County Shangrao 334000China

In order to obtain cytogenetic data of Odontobutis potamophila,head-kidney cells were collected as experimental materials to prepare chromosome specimen. The karyotypes of O. potamophila and the distribution and amount of transcriptionally active nucleolar organizer regions on chromosomes were analyzed by Giemsa staining and Ag-NORs. The results showed that the number of diploid chromosomes of O. potamophila was 44; the genome of O. potamophila was composed of 44 telocentric chromosomes; the karyotype formula was 2 n = 44 t,NF = 44; Ag-NORs were found in the paracentromeric region of chromosome. The results may lay the foundation for revealing the genetic pattern and chromosomal evolution of O. potamophila and contribute to further genetic breeding of O. potamophila.

关键词： Odontobutis potamophila Karyotype Ag-NORsHomec

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Panoptic UAV:Panoptic Segmentation of UAV Images for Marine Environment Monitoring

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工程与科学中的计算机建模(英文) 2024年第1期138卷 1001-1014页

作者： Yuling Dou Fengqin Yao xiandong Wang Liang Qu Long Chen Zhiwei xu Laihui Ding Leon Bevan Bullock Guoqiang Zhong Shengke Wang School of Computer Science and Technology Ocean University of ChinaQingdao266100China North China Sea Environmental Monitoring Center State Oceanic AdministrationQingdao266000China Department of Informatics University of LeicesterLeicesterLE17RHUK Research and Development Department Shandong Willand Intelligent Technology Co.Ltd.Qingdao266102China

UAV marine monitoring plays an essential role in marine environmental protection because of its flexibility and convenience,low cost and convenient maintenance.In marine environmental monitoring,the similarity between objects such as oil spill and sea surface,Spartina alterniflora and algae is high,and the effect of the general segmentation algorithm is poor,which brings new challenges to the segmentation of UAV marine images.Panoramic segmentation can do object detection and semantic segmentation at the same time,which can well solve the polymorphism problem of objects in UAV ocean images.Currently,there are few studies on UAV marine image recognition with panoptic segmentation.In addition,there are no publicly available panoptic segmentation datasets for UAV images.In this work,we collect and annotate UAV images to form a panoptic segmentation UAV dataset named UAV-OUC-SEG and propose a panoptic segmentation method named PanopticUAV.First,to deal with the large intraclass variability in scale,deformable convolution and CBAM attention mechanism are employed in the backbone to obtain more accurate features.Second,due to the complexity and diversity of marine images,boundary masks by the Laplacian operator equation from the ground truth are merged into feature maps to improve boundary segmentation precision.Experiments demonstrate the advantages of PanopticUAV beyond the most other advanced approaches on the UAV-OUC-SEG dataset.

关键词： Panoptic segmentation UAV marine monitoring attention mechanism boundary mask enhancement

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