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Two material removal modes in chemical mechanical polishing:mechanical plowing vs.chemical bonding

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Friction 2024年第5期12卷 897-905页

作者： Yuan WU Liang JIANG Wenhui LI Jiaxin ZHENG yushan chen Linmao QIAN Tribology Research Institute State Key Laboratory of Rail Transit Vehicle SystemSouthwest Jiaotong UniversityChengdu610031China

With the rapid development of semiconductors,the number of materials needed to be polished sharply increases.The material properties vary significantly,posing challenges to chemical mechanical polishing(CMP).Accordingly,the study aimed to classify the material removal mechanism.Based on the CMP and atomic force microscopy results,the six representative metals can be preliminarily classified into two groups,presumably due to different material removal modes.From the tribology perspective,the first group of Cu,Co,and Ni may mainly rely on the mechanical plowing effect.After adding H_(2)O_(2),corrosion can be first enhanced and then suppressed,affecting the surface mechanical strength.Consequently,the material removal rate(MRR)and the surface roughness increase and decrease.By comparison,the second group of Ta,Ru,and Ti may primarily depend on the chemical bonding effect.Adding H_(2)O_(2)can promote oxidation,increasing interfacial chemical bonds.Therefore,the MRR increases,and the surface roughness decreases and levels off.In addition,CMP can be regulated by tuning the synergistic effect of oxidation,complexation,and dissolution for mechanical plowing,while tuning the synergistic effect of oxidation and ionic strength for chemical bonding.The findings provide mechanistic insight into the material removal mechanism in CMP.

关键词： Chemical mechanical polishing corrosion wear material removal mode mechanical plowing chemical bonding

Brain region-specific roles of brain-derived neurotrophic factor in social stress-induced depressive-like behavior

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Neural Regeneration Research 2025年第1期20卷 159-173页

作者： Man Han Deyang Zeng Wei Tan Xingxing chen Shuyuan Bai Qiong Wu yushan chen Zhen Wei Yufei Mei Yan Zeng Brain Science and Advanced Technology Institute Wuhan University of Science and TechnologyWuhanHubei ProvinceChina Geriatric Hospital Affiliated to Wuhan University of Science and Technology WuhanHubei ProvinceChina School of Public Health Wuhan University of Science and TechnologyWuhanHubei ProvinceChina

Brain-derived neurotrophic factor is a key factor in stress adaptation and avoidance of a social stress behavioral response.Recent studies have shown that brain-derived neurotrophic factor expression in stressed mice is brain region–specific,particularly involving the corticolimbic system,including the ventral tegmental area,nucleus accumbens,prefrontal cortex,amygdala,and hippocampus.Determining how brain-derived neurotrophic factor participates in stress processing in different brain regions will deepen our understanding of social stress psychopathology.In this review,we discuss the expression and regulation of brain-derived neurotrophic factor in stress-sensitive brain regions closely related to the pathophysiology of depression.We focused on associated molecular pathways and neural circuits,with special attention to the brain-derived neurotrophic factor–tropomyosin receptor kinase B signaling pathway and the ventral tegmental area–nucleus accumbens dopamine circuit.We determined that stress-induced alterations in brain-derived neurotrophic factor levels are likely related to the nature,severity,and duration of stress,especially in the above-mentioned brain regions of the corticolimbic system.Therefore,BDNF might be a biological indicator regulating stress-related processes in various brain regions.

关键词： amygdala chronic mild stress chronic social defeat stress corticolimbic system depression hippocampus medial prefrontal cortex nucleus accumbens social stress models ventral tegmental area

Remarkable Wear Resistance in a Complex Concentrated Alloy with Nanohierarchical Architecture and Composition Undulation

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Research 2024年第1期2023卷 403-416页

作者： yushan Geng Wenyuan chen Hui Tan Jun cheng Shengyu Zhu Jun Yang Weimin Liu State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000PR China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049PR China Shandong Laboratory of Yantai Advanced Materials and Green Manufacturing Yantai 264000PR China

Sustained wear damages on the sliding surfaces of alloys are generally the culprit responsible for the failure of various mechanical systems.Inspired by high-entropy effects,here we deliberately deploy nanohierarchical architecture with composition undulation in a Ni50(AlNbTiV)_(50) complex concentrated alloy,which yields ultralow wear rate within the order of 10^(−7) to 10^(−6) mm^(3)/Nm between room temperature and 800℃.Such remarkable wear resistance heretofore represents one of the highest wear resistance reported for the bulk alloys or composites,and originates from the multi-type adaptive friction interface protection governed by intrinsically nano-coupled grains and nanoprecipitates.This cooperative heterostructure releases gradient frictional stress in stages upon wear at room temperature through the coexistence of multiple deformation pathways while activating a dense nanocrystalline glaze layer upon wear at 800℃ to minimize adhesive and oxidative wear.Our work uncovers a practical avenue for tailoring wear properties with multicomponent heterostructures over a wide temperature range.

关键词： wear alloys friction

Sequentially bridged MXene platelets for strong high‐temperature EM‐IR bi‐stealth sheets

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SmartMat 2024年第1期5卷 121-134页

作者： yushan Yang Kaicong chen Yipeng chen Chao Wang Baokang Dang Yingying Li Ming Liu Qingfeng Sun College of Chemistry and Materials Engineering Zhejiang A&F UniversityHangzhouChina Guangxi Fenglin Wood Industry Group Co.Ltd NanningChina

Combination of flexible multifunctional stealth technology properties such as electromagnetic(EM)and infrared(IR)stealth is crucial to the development of aerospace,military,and electronic fields,but the synthesis technology still has a significant challenge.Herein,we have successfully designed and synthesized highly flexible MXene@cellulose lamellae/borate ion(MXCB)sheets with strong high‐temperature EM‐IR bi‐stealth through sequential bridging of hydrogen and covalent bonds.The resultant MXCB sheets display high conductivity and good mechanical features such as flexibility,stretchability,fatigue resistance,and ultrasonic damage.MXCB sheets have a high tensile strength of 795 MPa.Furthermore,MXCB sheets with different thicknesses indicate exceptional high‐temperature thermal‐camouflage characteristics.This reduces the radiation temperature of the target object(>300°C)to 100°C.The conductivity of MXCB sheet with 3μm thickness is 6108 S/cm and the EM interference(EMI)shielding value is 39.74 dB.The normalized surface‐specific EMI SE absolute shielding effectiveness(SSE/t)is as high as 39312.78 dB·cm2/g,which remained 99.39%even after 10,000 times repeated folding.These multifunctional ultrathin MXCB sheets can be arranged by vacuum‐assisted induction to develop EM‐IR bi‐stealth sheet.

关键词： cellulose lamellae EM‐IR bi‐stealth mechanically strong MXene platelets transition metal carbides

Multiomics analysis reveals metabolic subtypes and identifies diacylglycerol kinase α (DGKA) as a potential therapeutic target for intrahepatic cholangiocarcinoma

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Cancer Communications 2024年第2期44卷 226-250页

作者： Weiren Liu Huqiang Wang Qianfu Zhao chenyang Tao Weifeng Qu yushan Hou Run Huang Zimei Sun Guiqi Zhu Xifei Jiang Yuan Fang Jun Gao Xiaoling Wu Zhixiang Yang Rongyu Ping Jiafeng chen Rui Yang Tianhao Chu Jian Zhou Jia Fan Zheng Tang Dong Yang Yinghong Shi Department of Liver Surgery and Transplantation Liver Cancer InstituteZhongshan HospitalFudan UniversityKey Laboratory of Carcinogenesis and Cancer Invasion of Ministry of EducationShanghaiP.R.China Research Unit of Liver cancer Recurrence and Metastasis Chinese Academy of Medical SciencesBeijingP.R.China State Key Laboratory of Medical Proteomics Beijing Proteome Research CenterNational Center for Protein Sciences(Beijing)Beijing Institute of LifeomicsBeijingP.R.China

Background:Intrahepatic cholangiocarcinoma(iCCA)is a highly heteroge-neous and lethal hepatobiliary tumor with few therapeutic strategies.The metabolic reprogramming of tumor cells plays an essential role in the develop-ment of tumors,while the metabolic molecular classification of iCCA is largely unknown.Here,we performed an integrated multiomics analysis and metabolic classification to depict differences in metabolic characteristics of iCCA patients,hoping to provide a novel perspective to understand and treat iCCA.Methods:We performed integrated multiomics analysis in 116 iCCA samples,including whole-exome sequencing,bulk RNA-sequencing and proteome anal-ysis.Based on the non-negative matrix factorization method and the protein abundance of metabolic genes in human genome-scale metabolic models,the metabolic subtype of iCCA was determined.Survival and prognostic gene analy-ses were used to compare overall survival(OS)differences between metabolic subtypes.Cell proliferation analysis,5-ethynyl-2’-deoxyuridine(EdU)assay,colony formation assay,RNA-sequencing and Western blotting were performed to investigate the molecular mechanisms of diacylglycerol kinaseα(DGKA)in iCCA cells.Results:Three metabolic subtypes(S1-S3)with subtype-specific biomarkers of iCCA were identified.These metabolic subtypes presented with distinct prog-noses,metabolic features,immune microenvironments,and genetic alterations.The S2 subtype with the worst survival showed the activation of some special metabolic processes,immune-suppressed microenvironment and Kirsten ratsar-coma viral oncogene homolog(KRAS)/AT-rich interactive domain 1A(ARID1A)mutations.Among the S2 subtype-specific upregulated proteins,DGKA was further identified as a potential drug target for iCCA,which promoted cell proliferation by enhancing phosphatidic acid(PA)metabolism and activating mitogen-activated protein kinase(MAPK)signaling.Conclusion:Viamultiomics analyses,we identified three metabolic subtypes of iCCA,revealing that the S2 subtype exhibited the poorest surviv

关键词： diacylglycerol kinaseα intrahepatic cholangiocarcinoma MAPK signaling metabolic classifi-cation multiomics analysis phosphatidic acid metabolism

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薄层水流冲刷条件下斜坡土体的临界起动

土木与环境工程学报（中英文） 2024年第2期46卷 23-32页

作者：王力陈玙珊占清华王世梅三峡库区地质灾害教育部重点实验室(三峡大学) 湖北宜昌443002

斜坡土体侵蚀是丘陵地区和水库岸坡普遍存在的灾害现象,其主要动力因素是降雨或者波浪上爬产生的薄层水流对土体产生的冲刷剪切作用。为探索水流冲刷作用下的斜坡土体临界起动条件,采用自主研发的冲刷起动试验装置,开展斜坡土体的冲刷... 详细信息

斜坡土体侵蚀是丘陵地区和水库岸坡普遍存在的灾害现象,其主要动力因素是降雨或者波浪上爬产生的薄层水流对土体产生的冲刷剪切作用。为探索水流冲刷作用下的斜坡土体临界起动条件,采用自主研发的冲刷起动试验装置,开展斜坡土体的冲刷起动试验和理论研究。通过颗粒染色和高倍数电子显微等技术手段观测无黏性土颗粒的起动现象,确定了无黏性岸坡土体的起动模式与水流流速的相互关系;探索了不同干密度、不同黏粒含量及不同坡度与黏土斜坡临界起动流速的相互关系,土体的黏粒含量、干密度及坡度对黏性土体的起动流速影响较大,与干密度和土体坡度相比,黏粒含量对黏土斜坡的起动流速影响更为明显。验证了无黏性岸坡土体的临界起动方程,其中滚动起动流速方程具有较强的可靠性;基于黏土的起动模式构建了黏土斜坡的起动力学平衡方程,获得了黏土斜坡半经验半理论的起动流速方程,用试验结果求解了起动流速方程的相关参数,最终确定的起动流速公式与试验结果拟合度较好,同时验证了起动流速公式的可靠性。

关键词：临界起动流速坡面流土体侵蚀起动模式薄层水流

互联网发展对技术创新的影响研究——基于知识产权保护的视角

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科研管理 2024年第3期45卷 151-160页

作者：陈伟邓堯李玉山张铄重庆工商大学企业管理研究中心重庆400067 重庆工商大学工商管理学院重庆400067 复旦大学管理学院上海200433

创新是引领发展的第一动力,是推动高质量发展、建设现代化经济体系的重要战略支撑。基于2012—2019年我国233个地级市的面板数据,实证检验互联网发展对技术创新的线性和非线性影响,并构建以知识产权保护为门槛变量的面板门槛模型,探讨... 详细信息

创新是引领发展的第一动力,是推动高质量发展、建设现代化经济体系的重要战略支撑。基于2012—2019年我国233个地级市的面板数据,实证检验互联网发展对技术创新的线性和非线性影响,并构建以知识产权保护为门槛变量的面板门槛模型,探讨知识产权保护在互联网发展影响技术创新中的作用机理。研究结果表明:(1)线性分析发现,互联网发展对技术创新具有显著的线性促进作用;(2)非线性分析发现,互联网发展对技术创新存在一个由不显著到显著促进且边际效应递减的非线性关系,非线性关系更契合互联网的“齐普夫法则”;(3)门槛效应检验发现,互联网发展对技术创新的影响存在以知识产权保护为门槛的单门槛效应,随着知识产权保护跨过门槛值,互联网发展对技术创新的促进作用呈现逐渐增强的趋势;(4)异质性分析发现,互联网发展对东部和中部地区技术创新具有显著的促进作用,对西部地区的影响并不显著;同时,互联网发展对实用新型专利的促进作用最强,对外观设计专利的促进作用最弱。研究结果在理论层面明晰了互联网发展、知识产权保护对技术创新的影响机理和作用机制,在实践层面为区域创新主体在合理的知识产权保护水平下发挥互联网技术优势实现创新驱动发展提供了理论借鉴和决策支持。

关键词：互联网发展技术创新知识产权保护门槛效应

甘肃靖远:为西部欠发达地区县域教育高质量发展探新路

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中国基础教育 2024年第1期 39-43页

作者：陈瑜山甘肃省白银市靖远县教育局甘肃白银730699

西部欠发达地区的县域教育发展面临着诸多挑战。为走出“上学难”“办学难”的双重困局,甘肃省靖远县不断强化党建引领,依托各个项目破解关键发展难题,从优化教育布局、推进学校标准化建设、系统提升教师队伍能力等多个方面综合发力,为... 详细信息

西部欠发达地区的县域教育发展面临着诸多挑战。为走出“上学难”“办学难”的双重困局,甘肃省靖远县不断强化党建引领,依托各个项目破解关键发展难题,从优化教育布局、推进学校标准化建设、系统提升教师队伍能力等多个方面综合发力,为西部欠发达地区县域教育优质均衡、高质量发展探出了一条行得稳、走得实的新路。

关键词：西部欠发达地区教育高质量发展县域教育城乡教育一体化发展城区学校扩容提质农村寄宿制学校

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奶牛肠道菌群紊乱与乳腺炎的关系

中国乳业 2024年第2期 65-70页

作者：陈玉山蒙阴县畜牧发展促进中心山东临沂276200

奶牛乳腺炎是养殖过程最常见疾病,对高产奶牛的生产性能、机体健康和免疫力造成巨大损害。肠道菌群和机体的多种疾病调节息息相关,肠道菌群可通过肠道-乳腺屏障进入乳房部位发挥作用,因此,针对肠道菌群稳态与乳腺炎发生发展的相关研究... 详细信息

奶牛乳腺炎是养殖过程最常见疾病,对高产奶牛的生产性能、机体健康和免疫力造成巨大损害。肠道菌群和机体的多种疾病调节息息相关,肠道菌群可通过肠道-乳腺屏障进入乳房部位发挥作用,因此,针对肠道菌群稳态与乳腺炎发生发展的相关研究具有重要意义。本文阐述乳腺炎危害和传播性、肠道菌群和乳腺炎的关系与影响、乳腺菌群和肠道菌群的关联等,为更深入了解乳腺炎发病机制与防控难点提供参考。

关键词：肠道菌群乳腺炎紊乱乳腺菌群