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Microstructure Evolution and Mechanical Properties of Friction Stir Welded Al-Cu-Li Alloy

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Acta Metallurgica Sinica(English Letters) 2024年第5期37卷 855-871页

作者： Peng Chen Wenhao Chen Jiaxin Chen Zhiyu Chen Yang Tang ge liu Bensheng Huang Zhiqing Zhang School of New Energy and Materials Southwest Petroleum UniversityChengdu 610500China Sichuan Provincial Engineering Research Center of Advanced Materials Manufacturing Technology for Shale Gas High-Efficient Exploitation Southwest Petroleum UniversityChengdu 610500China College of Materials Science and Engineering Chongqing UniversityChongqing 400045China School of Mechatronic Engineering Southwest Petroleum UniversityChengdu 610500China School of Robot Engineering Yangtze Normal UniversityChongqing 408100China

The investigation concentrates on friction stir welded(FSW)Al-Cu-Li alloy concerning its local microstructural evolution and mechanical *** grain features were characterized by electron back scattered diffraction(EBSD)technology,while precipitate characterization was conducted by using transmission electron microscopy(TEM)aligned along[011]Al and[001]Al zone *** mechanical properties are evaluated through micro-hardness and tensile *** can be found that nugget zones exhibit finely equiaxed grains evolved through complete dynamic recrystallization(DRX),primarily occurring in continuous dynamic recrystallization(CDRX)and discontinuous dynamic recrystallization(DDRX).In the thermal-mechanically affected zone(TMAZ),numerous sub-structured grains,exhibiting an elongated morphology,were created due to partial DRX,signifying the dominance of CDRX,DDRX,and geometric dynamic recrystallization(GDRX)in this region.T_(1)completely dissolves in the nugget zone(NZ)leading to the formation of Guinier-Preston zones and increase ofδ′,β′and S′.Conversely,T_(1)partially solubilizes in TMAZ,the lowest hardness zone(LHZ)and heat affected zone(HAZ),and the residual T_(1)undergoes marked coarsening,revealing various T_(1)*** solubilization and coarsening of T_(1)are primary contributors to the degradation of hardness and strength.θ′primarily dissolves and coarsens in NZ and TMAZ,whilst this precipitate largely coarsens in HAZ and LHZ.σ,TB,grain boundary phases(GBPs)and precipitate-free zone(PFZ)are newly generated during FSW.σexists in the TMAZ,LHZ and HAZ,whereas TB nucleates in *** and PFZ mostly develop in LHZ and HAZ,which can cause strain localization during tensile deformation,potentially leading to LHZ joint fracture.

关键词： Al-Cu-Li alloy Friction stir welding Microstructure evolution Mechanical properties

Influence of pore structure heterogeneity on channeling channels during hot water flooding in heavy oil reservoir based on CT scanning

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Petroleum Science 2024年第4期21卷 2407-2419页

作者： Qing-Jun Du Hao-Yu Zheng Jian Hou Yong-ge liu Jian-Fang Sun Dong Zhao State Key Laboratory of Deep Oil and Gas China University of Petroleum (East China) School of Petroleum Engineering China University of Petroleum (East China) Laboratory for Marine Mineral Resources Qingdao National Laboratory for Marine Science and Technology Petroleum Exploration and Production Research Institute

Hot water flooding is an effective way to develop heavy oil reservoirs. However, local channeling channels may form, possibly leading to a low thermal utilization efficiency and high water cut in the reservoir. The pore structure heterogeneity is an important factor in forming these channels. This study proposes a method that mixes quartz sand with different particle sizes to prepare weakly heterogeneous and strongly heterogeneous models through which hot water flooding experiments are *** the experiments, computer tomography(CT) scanning identifies the pore structure and micro remaining oil saturation distribution to analyze the influence of the pore structure heterogeneity on the channeling channels. The oil saturation reduction and average pore size are divided into three levels to quantitatively describe the relationship between the channeling channel distribution and pore structure heterogeneity. The zone where oil saturation reduction exceeds 20% is defined as a channeling *** scanning area is divided into 180 equally sized zones based on the CT scanning images, and threedimensional(3D) distributions of the channeling channels are developed. Four micro remaining oil distribution patterns are proposed, and the morphology characteristics of micro remaining oil inside and outside the channeling channels are analyzed. The results show that hot water flooding is more balanced in the weakly heterogeneous model, and the oil saturation decreases by more than 20% in most zones without narrow channeling channels forming. In the strongly heterogeneous model, hot water flooding is unbalanced, and three narrow channeling channels of different lengths form. In the weakly heterogeneous model, the oil saturation reduction is greater in zones with larger pores. The distribution range of the average pore size is larger in the strongly heterogeneous model. The network remaining oil inside the channeling channels is less than outside the channeling channels,

关键词： Heavy oil Hot water flooding Pore structure Channeling channels CT scanning

Re-estimating China's lake CO_(2)flux considering spatiotemporal variability

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Environmental Science and Ecotechnology 2024年第3期19卷 152-160页

作者： Zhidan Wen Yingxin Shang Lili Lyu Hui Tao ge liu Chong Fang Sijia Li Kaishan Song Northeast Institute of geography and Agroecology Chinese Academy of SciencesChangchun130102China School of Environment and Planning Liaocheng UniversityLiaocheng252000China

The spatiotemporal variability of lake partial carbon dioxide pressure(pCO_(2))introduces uncertainty into CO_(2)fluxestimates at the lakewater-air *** the variationpattern of pCO_(2)isimportant for obtaining accurate global *** we examine seasonal and trophic variations in lake pCO_(2)based on 13 field campaigns conducted in Chinese lakes from 2017 to *** found significant seasonal fluctuations in pCO_(2),with decreasing values as trophic states intensify within the same *** lakes exhibit lower pCO_(2)levels thanfreshwater *** pCO_(2)dynamics result invariable areal CO_(2)emissions,withlakes exhibiting different trophic states(oligotrophication>mesotrophication>eutrophication)and saline lakes differing from freshwater lakes(-23.1±17.4 vs.19.3±18.3 mmol m^(-2)d^(-1)).These spatiotemporal pCO_(2)variations complicate total CO_(2)emission *** area proportions of lakes with varying trophic states and salinity in China,we estimate China's lake CO_(2)flux at 8.07 Tg C yr^(-1).In future studies,the importance of accounting for lake salinity,seasonal dynamics,and trophic statesmust be noticed to enhance the accuracy of large-scale carbon emission estimates from lake ecosystems in the context of climate change.

关键词： Carbon dioxide Eutrophication Saline lakes Overestimation Carbon budget

Remote estimates of suspended particulate matter in global lakes using machine learning models

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International Soil and Water Conservation Research 2024年第1期12卷 200-216页

作者： Zhidan Wen Qiang Wang Yue Ma Pierre Andre Jacinthe ge liu Sijia Li Yingxin Shang Hui Tao Chong Fang Lili Lyu Baohua Zhang Kaishan Song Northeast Institute of geography and Agroecology CASChangchunJilin130102China Department of geology Indiana University∼Purdue UniversityIndianapolisIN44602USA University of Chinese Academy of Sciences Beijing100100China College of geography and Urban Planning Liaocheng UniversityLiaochengChina

Suspended particulate matter(SPM)in lakes exerts strong impact on light propagation,aquatic ecosystem productivity,which co-varies with nutrients,heavy metal and micro-pollutant in *** lakes,SPM exerts strong absorption and backscattering,ultimately affects water leaving signals that can be detected by satellite *** regression models based on specific band or hand ratios have been widely used for SPM estimate in the past with moderate *** are still rooms for model accuracy improvements,and machine learning models may solve the non-linear relationships between spectral variable and SPM in *** assembled more than 16,400 in situ measured SPM in lakes from six continents(excluding the Antarctica continent),of which 9640 samples were matched with Landsat overpasses within±7 *** machine learning algorithms and two simple regression methods(linear and partial least squares models)were used to estimate SPM in lakes and the performance were *** overcome the problem of imbalance datasets in regression,a Synthetic Minority Over-Sampling technique for regression with Gaussian Noise(SMOGN)was adopted in this *** comparison,we found that gradient boosting decision tree(GBDT),random forest(RF),and extreme gradient boosting(XGBoost)models demonstrated good spatiotemporal transferability with SMOGN processed dataset,and has potential to map SPM at different year with good quality of Landsat land surface reflectance *** all the tested modeling approaches,the GBDT model has accurate calibration(n=6428,R^(2)=0.95,MAPE=29.8%)from SPM collected in 2235 lakes across the world,and the validation(n=3214,R^(2)=0.84,MAPE=38.8%)also exhibited stable ***,the good performances were also exhibited by RF model with calibration(R^(2)=0.93)and validation(R^(2)=0.86,MAPE=24.2%)*** applied GBDT and RF models to map SPM of typical lakes,and satisfactory result was *** addition,the GBDT model was evaluated b

关键词： Landsat imagery Remote estimation SPM Transferability

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我国体育非物质文化遗产保护探赜

体育文化导刊 2024年第2期 58-64页

作者：刘戈国家体育总局体育文化发展中心北京100061

运用文献资料法、逻辑分析法等,探究我国体育非遗保护现状、困境,并提出保护路径。现状:完善的顶层设计提供了政策保障,多样化的保护措施构建了多元化保护模式,产业化发展模式推动保护工作可持续发展。困境:机制建设不完善,业态融合不足... 详细信息

运用文献资料法、逻辑分析法等,探究我国体育非遗保护现状、困境,并提出保护路径。现状:完善的顶层设计提供了政策保障,多样化的保护措施构建了多元化保护模式,产业化发展模式推动保护工作可持续发展。困境:机制建设不完善,业态融合不足,保护场域受限制,传承主体难以为继。路径:加强机制建设,营造良好环境;加强业态融合,全面激活动力;融入当代生活,展现时代价值;完善传承机制,增强存续力。

关键词：群众体育体育非物质文化遗产保护

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杜甫诗歌善用“细”字的语言艺术

中国文学研究 2024年第1期 43-50页

作者：刘燕歌西安邮电大学人文与外国语学院陕西西安710121

杜甫在炼字遣词方面对“细”字甚为钟情。诗中的“细”景建构起杜诗自然之维中独特的意象语言;同时,杜甫也擅长以“细”为标志语词缀织寻常事象,把羁旅生涯中的琐细情事与场景通过凸显细节的方式化入诗中,汇成了笔法细微而情意浓厚的艺... 详细信息

杜甫在炼字遣词方面对“细”字甚为钟情。诗中的“细”景建构起杜诗自然之维中独特的意象语言;同时,杜甫也擅长以“细”为标志语词缀织寻常事象,把羁旅生涯中的琐细情事与场景通过凸显细节的方式化入诗中,汇成了笔法细微而情意浓厚的艺术特征。杜诗因“细”而生的描写语言在诗性语言成熟的背景下呈现出个性魅力,深悉物情、体物活泼的笔法独具姿彩,而其宏微互映、大小兼涵的层叠意象结构也显示出更富表现张力及情感底蕴的诗体意境。

关键词：杜甫诗歌细景细事语词渊源艺术开拓

“党建引领”型社区志愿服务创新:必要性与机制

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湘潭大学学报（哲学社会科学版） 2024年第5期48卷 31-36,44页

作者：刘曼格湖南财政经济学院法学与公共管理学院湖南长沙410000

社区志愿服务的创新关系到新时代人们生活质量的高低。“党建引领”型社区志愿服务创新,既具有重要理论意义、实践意义和时代价值,又具有理论必然性和现实可能性。坚持和完善“党建引领”型社区志愿服务创新关键在于坚持人民至上和服务... 详细信息

社区志愿服务的创新关系到新时代人们生活质量的高低。“党建引领”型社区志愿服务创新,既具有重要理论意义、实践意义和时代价值,又具有理论必然性和现实可能性。坚持和完善“党建引领”型社区志愿服务创新关键在于坚持人民至上和服务优先的基本理念构建党建引领下志愿服务与志愿精神的价值引领机制,社区志愿服务与社区治理的全嵌入协同机制,社区志愿服务在场性和专业化服务能力提升的协同机制。

关键词： “党建引领”型社区志愿服务创新必要性机制

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淫羊藿次苷Ⅰ的药理活性研究现状

中国临床药理学杂志 2024年第9期40卷 1380-1384页

作者：张月刘格歌陈旺陕西理工大学生物科学与工程学院陕西汉中723000 秦巴生物资源与生态环境省部共建国家重点实验室(培育) 陕西汉中723000

淫羊藿是我国常见的一类补益类中草药,具有抗衰老、抑肿瘤、增强免疫力等功效。作为一种微量黄酮类化合物,淫羊藿次苷Ⅰ可从淫羊藿中分离,且具有多种药理活性,可以促进成骨转化、预防骨质疏松、抗肿瘤、保护心脏和调节肠道菌群等。淫羊... 详细信息

淫羊藿是我国常见的一类补益类中草药,具有抗衰老、抑肿瘤、增强免疫力等功效。作为一种微量黄酮类化合物,淫羊藿次苷Ⅰ可从淫羊藿中分离,且具有多种药理活性,可以促进成骨转化、预防骨质疏松、抗肿瘤、保护心脏和调节肠道菌群等。淫羊藿次苷Ⅰ作为一种天然药物活性成分,相对于许多化学药物具有药物不良反应发生率低、来源广泛、绿色安全等优势。本文旨在对近年来发表的关于淫羊藿次苷Ⅰ的药理活性的研究进行整理,为淫羊藿次苷Ⅰ的开发利用提供参考。

关键词：淫羊藿苷淫羊藿次苷Ⅰ 骨质疏松肿瘤药理活性

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我国智慧教育研究十年:聚焦、困境与突围

成人教育 2024年第2期44卷 30-36页

作者：刘选刘革平四川开放大学科研处成都610073 西南大学教育学部重庆400715

在国家大力推进教育新基建和落实教育现代化2035目标的背景下,智慧教育被置于更加重要的地位。采用文献研究法对2012年以来我国智慧教育的研究现状进行深入分析发现,当前我国智慧教育研究主要聚焦在教育信息化政策的宏观引领、创新技术... 详细信息

在国家大力推进教育新基建和落实教育现代化2035目标的背景下,智慧教育被置于更加重要的地位。采用文献研究法对2012年以来我国智慧教育的研究现状进行深入分析发现,当前我国智慧教育研究主要聚焦在教育信息化政策的宏观引领、创新技术对智慧教育的全方位赋能、智慧教学在实践领域的落地实施三大方面。同时,我国智慧教育研究也凸显出对智慧与智能等核心概念存在认识偏差、对智慧教学中技术的效用限度和伦理存在争议、对智慧教学的设计与实施流于套路等困境。未来我国智慧教育研究应该突破学科壁垒,增强跨学科理解;合理认识技术的功效与局限,正确处理由技术引发的伦理问题;重视智慧教学设计,切实提升智慧学习实效。

关键词：智慧教育发展现状关键问题突破路径研究综述