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功率密度对DP590钢激光焊缝熔深及组织的影响

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精密成形工程 2020年第1期12卷 111-116页

作者：孙旭张林杰 na suck-joo 西安交通大学

目的研究相同热输入(功率/速度)下激光功率密度(功率/光斑面积)变化对焊缝熔深及组织的影响。方法在保持热输入不变的条件下,对不同功率下1.8 mm厚的DP590钢板进行光纤激光焊接试验,在光学显微镜下检测不同条件下的熔深,在扫描电镜下观... 详细信息

目的研究相同热输入(功率/速度)下激光功率密度(功率/光斑面积)变化对焊缝熔深及组织的影响。方法在保持热输入不变的条件下,对不同功率下1.8 mm厚的DP590钢板进行光纤激光焊接试验,在光学显微镜下检测不同条件下的熔深,在扫描电镜下观察不同条件下的焊缝组织。然后,采用FLOW-3D软件对不同条件下焊接熔池/小孔行为与激光能量吸收进行了计算研究。结果随着功率密度的增加,焊缝熔深总体不断递增,但在速度为0.055 m/s和0.065 m/s时突变。结论通过模拟发现,匙孔吸收的能量影响了焊缝熔深变化。同时,焊缝冷却速率随着焊缝吸收能量的增加而降低,使得焊缝区马氏体组织大小出现差异。

关键词： DP590钢激光焊接 CFD模拟焊缝组织及熔深

HXD2机车转向架拉杆座角焊缝疲劳失效机理

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焊接 2022年第7期 40-47页

作者：马呈祥龙健张林杰 na suck joo 中车大同电力机车有限公司山西大同037038 西安交通大学金属材料强度国家重点实验室西安710049 韩国科学技术院大田34141韩国

针对HXD2型电力机车在某穿越秦岭山脉线路服役中多台次拉杆座角焊缝出现裂纹的问题,进行了试验与仿真分析。发现裂纹表面有明显疲劳辉纹,表明角焊缝服役中发生疲劳失效;焊缝根部是疲劳起裂位置,有多源起裂形貌特征;起裂后裂纹从中心向... 详细信息

针对HXD2型电力机车在某穿越秦岭山脉线路服役中多台次拉杆座角焊缝出现裂纹的问题,进行了试验与仿真分析。发现裂纹表面有明显疲劳辉纹,表明角焊缝服役中发生疲劳失效;焊缝根部是疲劳起裂位置,有多源起裂形貌特征;起裂后裂纹从中心向两侧扩展、从根部向焊缝表面扩展,在接头横截面上裂纹路径与水平方向夹角近似为45°;统计分析和仿真计算表明,角焊缝裂纹的发生与拉杆座/基板之间的间隙值有关联性,根部间隙越大,则角焊缝抗疲劳性能越差;分析其主要机理是间隙较小时,焊缝受压后拉杆座底面与构架基板表面更容易发生接触,接触后基板表面分担部分载荷。因此,间隙较小时,焊缝应力幅较小;而间隙较大时,不仅应力幅较大,而且在焊根处易出现末端尖劈形貌。

关键词：拉杆座角焊缝疲劳裂纹根部间隙末端尖劈

Improving thermal efficiency and stability of laser welding process for magnesium alloy by combining power modulation and subatmospheric pressure environment

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Journal of Magnesium and Alloys 2022年第10期10卷 2788-2800页

作者： Jie Ning suck-joo na Lin-Jie Zhang Xiang Wang Jian Long Won-Ik Cho State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an 710049China BIAS-Bremer Institut für angewandte Strahltechnik GmbH Klagenfurter Straße 528359 BremenGermany

The laser welding(LW)process of highly reflective materials presents low thermal efficiency and poor *** solve the problem,the effects of subatmospheric environment on LW process,technological parameters in subatmospheric environment on weld formation and welding with sinusoidal modulation of laser power on the stability of LW process in subatmospheric environment were *** AZ31magnesium(Mg)alloy was used as the test *** test result revealed that the weld penetration in subatmospheric environment can increase by more than ten times compared with that under normal *** the keyhole depth greatly rises,significantly periodic local bulge is observed on the backwall surface of the keyhole and the position of the bulge shifts along the direction of the keyhole ***,the hump-shaped surface morphology of the welded seam is formed;moreover,the weld width in local zones in the lower part of the welded seam remarkably *** LW in subatmospheric environment,the weld penetration can be further greatly increased through power ***,power modulation can inhibit the occurrence of bulges in local zones on the backwall of the keyhole during LW in subatmospheric environment,thus further curbing the significant growth of the weld widths of hump-shaped welding beads and local zones in the lower part of welded ***,the mechanism of synchronously improving the thermal efficiency and stability of LW process of highly reflective materials through power modulation in subatmospheric environment was *** was conducted according to theoretical analysis of recoil pressure and observation results of dynamic behaviors of laser induced plasma clouds and keyholes in the molten pool through high speed photography.

关键词： Laser welding Subatmospheric environment Power modulation Highly reflective materials Thermal efficiency Stability

A comprehensive review on the resynthesis of ternary cathode active materials from the leachate of Li-ion batteries

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Journal of Energy Chemistry 2024年第8期95卷 446-463,I0010页

作者： Dongwoo Kim Hyeoncheol joo Chanmin Kim Seoa Kim Wan-Yi Kim Sangwoo Han joongkil Park Soyeon Park Heechul Jung Sanghyuk Park Kyungjung Kwon Department of Energy and Mineral Resources Engineering Sejong UniversitySeoul 05006Republic of Korea LIB Recycling Research Group LIB Materials R&D CenterPOSCO HoldingsPohang 37859Republic of Korea Department of Future Energy Convergence Seoul National University of Science&Technology232 Gongreung-roNowon-guSeoul 01811Republic of Korea Autonomous Intelligent Unmanned Flying Vehicles Institute Sejong UniversitySeoul 05006Republic of Korea

This review highlights the importance of recovering valuable metals from spent Li-ion battery(LIB)cathodes through the resynthesis of cathode active materials(CAMs).The resynthesis process of CAMs,a promising recycling method that directly produces CAM precursors from LIB leachate,is *** process encompasses six key steps,including pretreatment,leaching,purification,adjustment of metal concentrations,precursor synthesis,and *** review also investigates the potential introduction of impurity elements during CAM resynthesis and provides tolerance levels for these impurities based on thorough reference ***,it addresses challenges related to the commercialization of the resynthesis ***,this review represents the first comprehensive assessment of CAM resynthesis,including the systematic evaluation of 12 impurity elements(Fe,Li,Al,Cu,C,P,F,na,Cl,S,Mg,and Zn).Overall,this comprehensive review is poised to support the commercial development of resynthesized CAMs by offering valuable guidelines for managing impurities and streamlining the purification process.

关键词： Li-ion battery Recycling Resynthesis Leachate Impurity

Defect Engineering in Earth-Abundant Cu_(2)ZnSnSe_(4) Absorber Using Efficient Alkali Doping for Flexible and Tandem Solar Cell Applications

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Energy & Environmental Materials 2024年第2期7卷 249-256页

作者： Muhammad Rehan Ara Cho Inyoung Jeong Kihwan Kim Asmat Ullah Jun-Sik Cho joo Hyung Park Yunae Jo Sung Jun Hong Seung Kyu Ahn SeJin Ahn Jae Ho Yun Jihye Gwak Donghyeop Shin Photovoltaics Research Department Korea Institute of Energy Research(KIER)152-Gajeong-roYuseong-guDaejeon 34129Korea Department of Renewable Energy Engineering University of Science and Technology(UST)217-Gajeong-roYuseong-guDaejeon 34113Korea Korea Institute of Energy Technology(KENTECH) 50772 Ujeong-roNaju Jeonnam 58217Korea

To demonstrate flexible and tandem device applications,a low-temperature Cu_(2)ZnSnSe_(4)(CZTSe)deposition process,combined with efficient alkali doping,was ***,high-quality CZTSe films were grown at 480℃by a single co-evaporation,which is applicable to polyimide(PI)*** of the alkali-free substrate,na and K alkali doping were systematically studied and optimized to precisely control the alkali distribution in *** bulk defect density was significantly reduced by suppression of deep acceptor states after the(naF+KF)*** the low-temperature deposition with(naF+KF)PDTs,the CZTSe device on glass yields the best efficiency of 8.1%with an improved Voc deficit of 646 *** developed deposition technologies have been applied to *** the first time,we report the highest efficiency of 6.92%for flexible CZTSe solar cells on ***,CZTSe devices were utilized as bottom cells to fabricate four-terminal CZTSe/perovskite tandem cells because of a low bandgap of CZTSe(~1.0 eV)so that the tandem cell yielded an efficiency of 20%.The obtained results show that CZTSe solar cells prepared by a low-temperature process with in-situ alkali doping can be utilized for flexible thin-film solar cells as well as tandem device applications.

关键词： alkali doping Earth-abundant Cu_(2)ZnSnSe_(4) flexible solar cells four-terminal tandem cells low-temperature process

Nb521高温合金光纤激光焊及接头组织性能研究

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应用激光 2023年第7期43卷 49-57页

作者：刘喜旺贾金龙张林杰 suck joo na 西安交通大学金属材料强度国家重点实验室陕西西安710049 兰州工业学院材料工程学院甘肃兰州730050

对Nb521(Nb-5W-2Mo-1Zr)进行光纤激光焊接工艺试验,研究不同的工艺参数对焊缝成形及宏观形貌的影响,并对焊接接头的显微组织和力学性能进行分析。保持焊接功率为6 kW不变,分别改变焊接速度和离焦量,结果表明,随焊接速度增大,焊缝塌陷有... 详细信息

对Nb521(Nb-5W-2Mo-1Zr)进行光纤激光焊接工艺试验,研究不同的工艺参数对焊缝成形及宏观形貌的影响,并对焊接接头的显微组织和力学性能进行分析。保持焊接功率为6 kW不变,分别改变焊接速度和离焦量,结果表明,随焊接速度增大,焊缝塌陷有所改善,但焊缝连续性逐渐变差,当焊接速度达到一定值时,焊缝背面出现了许多不连续的驼峰。当离焦量为正时,成形质量差。当离焦量为负时,焊缝咬边现象有所改善。当激光功率为6 kW,焊接速度为45 mm/s,离焦量为-1 mm时,焊缝成形良好。在优化的工艺参数下,焊缝为粗大的垂直于熔合线的柱状晶组织,母材为细小的等轴晶组织。焊接接头常温抗拉强度平均值可达到481 MPa,与母材抗拉强度相当,焊接接头分别断裂于热影响区及母材,且均为韧性断裂;焊缝处的显微硬度高于母材和热影响区的显微硬度。在焊接接头的上部和下部,热影响区显微硬度发生软化,低于母材显微硬度。在焊接接头的中部,热影响区的显微硬度与母材相当。

关键词：激光技术激光自熔焊铌钨合金显微组织力学性能

Jacobsen syndrome with bilateral periventricular white matter lesions

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World Journal of Pediatrics 2022年第2期18卷 142-143页

作者： Hyun-joo Lee Hae-ln Lee Ji-Hoon na Young-Mock Lee Department of Pediatrics Yonsei University College of MedicineSeoulKorea Department of Pediatrics Gangnam Severance HospitalYonsei University College of Medicine21Eonju-roGangnam-guSeoul 06273Korea

A 2-month-old girl presented facial dimorphism,including frontal bossing,hypertelorism,a broad nasal bridge,low-set ears,hypotonia with mild spasticity,and mild *** head circumference was 40.8 cm(75-90 percentile).The... 详细信息

关键词： white ism Jacobsen

Pyruvate dehydrogenase kinase is a negative regulator of interleukin-10 production in macrophages

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Journal of Molecular Cell Biology 2020年第7期12卷 543-555页

作者： Yi Rang na Daun Jung Juha Song Jong-Wan Park Jung joo Hong Seung Hyeok Seok Macrophage Lab Department of Microbiology and Immunology and Institute of Endemic DiseaseSeoul National University College of MedicineChongno-guSeoul 03080Republic of Korea Department of Biomedical Science BK21-Plus Education ProgramSeoul National University College ofMedicineJongno-guSeoul 03080Republic of Korea Department of Pharmacology Seoul National University College of MedicineJongno-guSeoul 03080Republic of Korea Cancer Research Institute and Ischemic/Hypoxic Disease Institute Seoul National University College ofMedicineJongno-guSeoul 03080Republic of Korea national Primate Research Center Korea Research Institute of Bioscience and BiotechnologyCheongju 28116Republic of Korea

Interleukin-10(IL-10)is the most potent anti-inflammatory cytokine in the body and plays an essential role in determining outcomes of many inflammatory *** metabolism is a critical determinant of immune cell function;however,it is currently unclear whether metabolic processes are specifically involved in IL-10 *** this study,we aimed to find the central metabolic molecule regulating IL-10 production of macrophages,which are the main producers of *** analysis identified that metabolic changes were predominantly enriched in Kupffer cells at the early inflammatory phase of a mouse endotoxemia *** them,pyruvate dehydrogenase kinase(PDK)-dependent acute glycolysis was negatively involved in IL-10 *** or knockdown of PDK selectively increased macrophage IL-10 ***,PDK inhibition increased IL-10 production via profound phosphorylation of adenosine monophosphate(AMP)-activated protein kinase alpha 1(AMPKα1)by restricting glucose uptake in lipopolysaccharide-stimulated ***α1 consequently activated p38 mitogen-activated protein kinase,c-Jun N-terminal kinase,and cyclic AMP-responsive element-binding protein to regulate IL-10 *** study uncovers a previously unknown regulatory mechanism of IL-10 in activated macrophages involving an immunometabolic function of PDK.

关键词： macrophage pyruvate dehydrogenase kinase AMP-activated protein kinase interleukin-10

Mitophagy links oxidative stress conditions and neurodegenerative diseases

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Neural Regeneration Research 2019年第5期14卷 749-756页

作者： Ulfuara Shefa na Young Jeong In Ok Song Hyung-joo Chung Dokyoung Kim Junyang Jung Youngbuhm Huh Department of Biomedical Science Graduate School Kyung Hee University Department of Anatomy and Cell Biology College of Medicine Dong-A University Department of Reproductive Endocrinology and Infertility Department of Obstetrics and Gynecology Cheil General Hospital Dankook University College of Medicine Department of Anesthesiology and Pain Medicine College of Medicine Kosin University Department of Anatomy and Neurobiology College of Medicine Kyung Hee University

Mitophagy is activated by a number of stimuli, including hypoxia, energy stress, and increased oxidative phosphorylation activity. Mitophagy is associated with oxidative stress conditions and central neurodegenerative diseases. Proper regulation of mitophagy is crucial for maintaining homeostasis; conversely, inadequate removal of mitochondria through mitophagy leads to the generation of oxidative species, including reactive oxygen species and reactive nitrogen species, resulting in various neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. These diseases are most prevalent in older adults whose bodies fail to maintain proper mitophagic functions to combat oxidative species. As mitophagy is essential for normal body function, by targeting mitophagic pathways we can improve these disease conditions. The search for effective remedies to treat these disease conditions is an ongoing process, which is why more studies are needed. Additionally, more relevant studies could help establish therapeutic conditions, which are currently in high demand. In this review, we discuss how mitophagy plays a significant role in homeostasis and how its dysregulation causes neurodegeneration. We also discuss how combating oxidative species and targeting mitophagy can help treat these neurodegenerative diseases.

关键词： nerve regeneration mitophagy central nervous system Alzheimer’s disease Parkinson’s disease Huntington’s disease amyotrophic lateral sclerosis oxidative species reactive oxygen species reactive nitrogen species