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Preheating-assisted solid-state friction stir repair of Al-Mg-Si alloy plate at different rotational speeds

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International Journal of Minerals,Metallurgy and Materials 2024年第4期31卷 725-736页

作者： Hui Wang Yidi Li Ming Zhang Wei Gong Ruilin lai Yunping Li State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China Research Institute of Light Alloy Central South UniversityChangsha 410083China

Additive friction stir deposition(AFSD)is a novel structural repair and manufacturing technology has become a research hotspot at home and abroad in the past five *** this work,the microstructural evolution and mechanical performance of the Al-Mg-Si alloy plate repaired by the preheating-assisted AFSD process were *** evaluate the tool rotation speed and substrate preheating for repair quality,the AFSD technique was used to additively repair 5 mm depth blind holes on 6061 aluminum alloy *** results showed that preheat-assisted AFSD repair significantly improved joint bonding and joint strength compared to the control non-preheat substrate ***,increasing rotation speed was also beneficial to improve the metallurgical bonding of the interface and avoid volume *** preheating conditions,the UTS and elongation were positively correlated with rotation *** the process parameters of preheated substrate and tool rotation speed of 1000 r/min,defect-free specimens could be obtained accompanied by tensile fracture occurring in the substrate rather than the repaired *** UTS and elongation reached the maximum values of 164.2MPa and 13.4%,which are equivalent to 99.4%and 140%of the heated substrate,respectively.

关键词： additive friction stir deposition structural repair tool rotation speed Al alloy

Biomineralization of soil with crude soybean urease using different calcium salts

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第5期16卷 1788-1798页

作者： Yajie Weng Junjie Zheng Hanjiang lai Mingjuan Cui Xingzhi Ding School of Civil and Hydraulic Engineering Huazhong University of Science and TechnologyWuhan430074China Zijin School of Geology and Mining Fuzhou UniversityFuzhou350108China College of Civil Engineering Fuzhou UniversityFuzhou350116China

Calcium salt is an important contributing factor for calcium-based *** study the effect of calcium salt on soil biomineralization using crude soybean urease,the calcium salts,including the calcium chloride (CaCl_(2)),calcium acetate ((CH_(3)COO)_(2)Ca) and calcium nitrate (Ca(NO_(3))_(2)),were used to prepare the biotreatment solution to carry out the biomineralization tests in this *** series of biomineralization tests in solution and sand column,respectively,were *** electron microscopy (SEM) and X-ray diffraction (XRD) were performed to determine the microscopic characteristics of the precipitated calcium carbonate (CaCO_(3)) *** experimental results indicate that the biomineralization effect is the best for the CaCl2 case,followed by (CH_(3)COO)_(2)Ca,and worst for Ca(NO_(3))_(2) under the test conditions of this study (i.e.1 mol/L of calcium salt-urea).The mechanism for the effect of the calcium salt on the biomineralization of crude soybean urease mainly involves: (1) inhibition of urease activity,and (2) influence on the crystal size and morphology of CaCO_(3).Besides Ca^(2+) ,the anions in solution can inhibit the activity of crude soybean urease,and NO_(3)− has a stronger inhibitory effect on the urease activity compared with both CH_(3)COO^(−) and Cl^(−) .The co-inhibition of Ca^(2+) and NO_(3)− on the activity of urease is the key reason for the worst biomineralization of the Ca(NO_(3))_(2) case in this *** difference in biomineralization between the CaCl_(2) and (CH_(3)COO)_(2) Ca cases is strongly correlated with the crystal morphology of the precipitated CaCO_(3).

关键词： Biomineralization Crude soybean urease Calcium salt Influence mechanism

First-principles study on the electronic structure of Pb_(10−x)Cu_(x)(PO_(4))_(6)O(x=0,1)

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Journal of Materials Science & Technology 2024年第4期171卷 66-70页

作者： Junwen lai Jiangxu Li Peitao Liu Yan Sun Xing-Qiu Chen Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China

Recently,Lee et *** the experimental discovery of room-temperature ambient-pressure super-conductivity in a Cu-doped lead-apatite(LK-99)(arXiv:2307.12008,arXiv:2307.12037).Remarkably,the claimed superconductivity can persist up to 400 K at ambient *** the experimental im-plication,the electronic structure of LK-99 has not yet been ***,we investigate the electronic structures of LK-99 and its parent compound using first-principles calculations,aiming to elucidate the doping effects of *** results reveal that the parent compound Pb_(10)(PO_(4))_(6)O is an insulator,while Cu doping induces an insulator-metal transition and thus volume *** band structures of LK-99 around the Fermi level are featured by a half-filled flat band and a fully-occupied flat *** two very flat bands arise from both the 2p orbitals of 1/4-occupied O atoms and the hybridization of the 3d orbitals of Cu with the 2p orbitals of its nearest-neighboring O ***,we observe four van Hove singularities on these two flat ***,we show that the flat band structures can be tuned by including electronic correlation effects or by doping different *** find that among the considered doping elements(Ni,Cu,Zn,Ag,and Au),both Ni and Zn doping result in the gap opening,whereas Au exhibits doping effects more similar to Cu than *** work establishes a foundation for fu-ture studies to investigate the role of unique electronic structures of LK-99 in its claimed superconducting properties.

关键词： First-principles calculations Density functional theory Electronic structur e Superconductivity Flat bands Strongly correlated electrons

Permanent Magnet Temperature Estimation for PMSMs Using Virtual Position-offset Injection

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CES Transactions on Electrical Machines and Systems 2024年第1期8卷 51-60页

作者： Beichen Ding Yuting Lu Kaide Huang Guodong Feng Chunyan lai IEEE the School of Intelligent Systems Engineering Sun Yat-sen UniversityShenzhen 518107China the Fosan University Foshan 528225China the Department of Electrical and Computer Engineering Concordia UniversityQCCanada

This paper proposes a virtual position-offset injection based permanent magnet temperature estimation approach for permanent magnet synchronous machines(PMSMs). The concept of virtual position-offset injection is mathematically transforming the machine model to a virtual frame with a position-offset. The virtual frame temperature estimation model is derived to calculate the permanent magnet temperature(PMT) directly from the measurements with computation efficiency. The estimation model involves a combined inductance term, which can simplify the establishment of saturation compensation model with less measurements. Moreover, resistance and inverter distorted terms are cancelled in the estimation model, which can improve the robustness to the winding temperature rise and inverter distortion. The proposed approach can achieve simplified computation in temperature estimation and reduced memory usage in saturation compensation. While existing model-based approaches could be affected by either the need of resistance and inverter information or complex saturation compensation. Experiments are conducted on the test machine to verify the proposed approach under various operating conditions.

关键词： PMSM Magnet temperature estimation Virtual position offset injection Inverter nonlinearity

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产品湿热试验质量控制与改进

电子质量 2010年第2期 52-53页

作者：赖波四川省绵阳市九洲集团公司质量管理监督处

1引言军用设备一般按照CdB150—86《军用设备环境试验方法》规定的方法开展科研、生产和交收等各阶段的环境试验，其中湿热试验按照GJB 150．9-86《军用设备环境试验方法湿热试验》规定的方法进行，湿热试验的目的是确定军用设备在高温... 详细信息

1引言军用设备一般按照CdB150—86《军用设备环境试验方法》规定的方法开展科研、生产和交收等各阶段的环境试验，其中湿热试验按照GJB 150．9-86《军用设备环境试验方法湿热试验》规定的方法进行，湿热试验的目的是确定军用设备在高温及高湿环境条件下的适应性。公司依据GJB 150—86《军用设备环境试验方法》，针对产品特点制定产品技术规范，明确了产品的试验条件、试验方法和合格判据，并依此开展环境试验。

关键词：湿热试验产品特点质量控制军用设备试验方法设备环境环境试验高湿环境

水工环地质勘察及遥感技术在地质工作中的应用研究

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云南化工 2018年第4期45卷 205-206页

作者：赖波广东省珠海工程勘察院广东珠海519000

对遥感技术进行了分析,同时分析了水工环地质勘察以及遥感技术在地质工作当中的具体应用,希望对广大同行提供一定的参考价值。

关键词：水工环地质勘察遥感技术地质工作应用

广东省珠海市地质灾害发育特征及形成条件分析

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资源信息与工程 2020年第4期35卷 110-114页

作者：赖波广东省珠海工程勘察院广东珠海519000

近年来,随着珠海市经济社会的快速发展,极端天气及人类工程建设活动引发的地质灾害现象呈加剧趋势,并形成了大量不稳定斜坡,严重危害人类生命及财产安全。因此,查明珠海市地质灾害发育特征及形成条件,对政府部门及工程建设单位预防地质... 详细信息

近年来,随着珠海市经济社会的快速发展,极端天气及人类工程建设活动引发的地质灾害现象呈加剧趋势,并形成了大量不稳定斜坡,严重危害人类生命及财产安全。因此,查明珠海市地质灾害发育特征及形成条件,对政府部门及工程建设单位预防地质灾害、国土空间规划和促进经济社会可持续发展具有重要意义。

关键词：地质灾害发育特征形成条件分析珠海市

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“讲读课”对作文教学的影响

玉溪师范学院学报 2009年第2期25卷 68-70页

作者：赖波玉溪师范学院附属中学云南玉溪653100

阅读教学是作文教学的后盾,抓好阅读教学,对推动学生作文进步具有重要意义。"讲读课"对作文教学的影响主要表现在:讲读课为作文教学提供范文,为学生积累作文素材,有利于学生的作文技法训练和作文思维训练,有利于学生陶冶情操。

关键词：中学教育语文教学作文教学

Small object detection on highways via balance feature fusion and task-specific encoding network

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Optoelectronics Letters 2024年第7期20卷 424-429页

作者： YU Minming CHAN Sixian ZHOU Xiaolong lai Zhounian College of Computer Science and Technology Zhejiang University of TechnologyHangzhou 310023China Hangzhou Xsuan Technology Co. Ltd.Hangzhou 310051China Quzhou University Quzhou 324000China Huzhou Institute of Zhejiang University Huzhou 313002China2

Detecting small objects on highways is a novel research *** to the small pixel of objects on highways,traditional detectors have difficulty in capturing discriminative ***,the imbalance of feature fusion methods and the inconsistency between classification and regression tasks lead to poor detection performance on *** this paper,we propose a balance feature fusion and task-specific encoding network to address these ***,we design a balance feature pyramid network(FPN)to integrate the importance of each layer of feature maps and construct long-range dependencies among them,thereby making the features more *** addition,we present task-specific decoupled head,which utilizes task-specific encoding to moderate the imbalance between the classification and regression *** demonstrated by extensive experiments and visualizations,our method obtains outstanding detection performance on small object detection on highways(HSOD)dataset and AI-TOD dataset.

关键词： network utilize highway