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Microstructural Features and Mechanical Behaviors of Al_(0.5)Cr_(0.8)CoFeNi_(2.5)V_(0.2) High-Entropy Alloys Fabricated by Selective Laser Melting Technique

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Acta Metallurgica Sinica(English Letters) 2022年第10期35卷 1591-1606页

作者： Yao Yan Wei-Dong song Ke-Feng Li Kang Zhao Tong-Tong Sun kai-kai song Jian-Hong Gong Li-Na Hu Shenzhen Research Institute of Shandong University Shenzhen518057China State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China Guangdong Institute of Materials and Processing Guangdong Academy of SciencesGuangdong UniversityGuangzhou510650China School of Mechanical Electrical and Information EngineeringShandong UniversityWeihai264209China Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) Shandong UniversityJinan250061China

In this work,high strength and ductile Al_(0.5)Cr_(0.8)CoFeNi_(2.5)V_(0.2) high-entropy alloys(HEAs)were fabricated by the selective laser melting(SLM)*** orthogonal experiments,it was verified that a wide SLM processing parameter window can be used to produce crack-free samples for the investigated *** the printed HEA samples exhibit good densification higher than 98.3%.It was found that obvious epitaxial growth leads to the formation of the cylindrical and equiaxed ordered face-centered cubic(FCC)crystals,displaying the characteristics of sub-cylindrical and sub-cellular *** low-angle grain boundaries(LAGBs)prefer appearing around subgrain structures,while the high-angle grain boundaries(HAGBs)tend to form around coarse *** HEA samples with high and low apparent densities were selected to observe their mechanical properties,which exhibit Vickers hardness higher than 263 HV and do not fail during *** increasing densification,the strength gradually *** to the engineering stress–strain curves during compression,the yield strength is higher than 530 MPa,while the strength near 40%engineering strain is larger than 1840 *** deformation,a large density of dislocations becomes popular within subgrain structures together with the pre-existing dislocations from rapid solidification,leading to the formation of planar and cross slip *** coarse cylindrical crystals,some deformation twins are also induced together with the appearance of a distinct copper-type texture during *** a result,the as-printed samples display better mechanical properties than the as-cast *** present studies provide a very good HEA candidate for the SLM process,but more work should be conducted to achieve excellent comprehensive properties.

关键词： High-entropy alloys Selective laser melting Mechanical properties Microstructures

Enhanced mechanical performance of gradient-structured CoCrFeMnNi high-entropy alloys induced by industrial shot-blasting

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Rare Metals 2023年第3期42卷 982-993页

作者： Ming-Zhi Zhang Kun Zhang kai-kai song Xiao-Yu Zou Wei-Dong song Ke-Feng Li Li-Na Hu Ze-Qun Zhang Jürgen Eckert Shenzhen Research Institute of Shandong University Shenzhen 518057China CAS Key Laboratory of Microgravity(National Microgravity Laboratory) Institute of MechanicsChinese Academy of SciencesBeijing100190China State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China School of Mechanical Electrical and Information EngineeringShandong UniversityWeihai 264209China Guangdong Institute of Materials and Processing Guangdong Academy of SciencesGuangzhou 510650China Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) Shandong UniversityJinan 250061China Erich Schmid Institute of Materials Science Austrian Academy of SciencesLeoben 8700Austria Department of Materials Science Montanuniversitat LeobenLeoben 8700Austria

In this study,CoCrFeMnNi high-entropy alloys(HEAs)with a surface gradient nanostructure were produced using industrial shot blasting,which improved their mechanical properties compared to the untreated *** severely plastically deformed(SPD)surface layer had a multi-scale hierarchical structure with a high density of stacking faults,deformation nanotwins,and amorphous *** depth of the SPD layer steadily increased as the shot-blasting time *** differences in the microhardness and tensile strength before and after shotblasting demonstrated the significant effect of the SPD layer on the mechanical *** microhardness of the homogenized HEA was~5 *** comparison,the maximum microhardness of the specimens after 20 min of shot blasting was~8.0 GPa at the *** yield strength also improved by 178%,and a large ductility of~36%was *** nanograin boundary,stacking fault,and twin strengthening within the gradientnanostructured surface layer caused the strength to *** tensile deformation,strain concentration began at the surface of the specimen and gradually spread to the ***,the gradient-nanostructured surface layer with improved strain hardening can prevent early necking and ensure steady plastic deformation so that high toughness is achieved.

关键词： High-entropy alloy Shot blasting Gradient structure Mechanical property Deformation mechanism

Effect of pre-existing shear bands on mechanical properties and serration behaviors in bulk metallic glasses

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Journal of Iron and Steel Research International 2017年第4期24卷 402-410页

作者： Xu-dong Yuan Sheng-hai Wang kai-kai song Xiao-liang Han Yu-sheng Qin Dong-fang Li Xue-lian Li Bo song Hui Xing Li Wang School of Mechanical Electrical &Information EngineeringShandong University(Weihai) School of Science Northwestern Polytechnical University

Pre-existing（multiple）shear bands were introduced into the ductile Zr56Co28Al16 and Zr65Ni10Cu15Al10bulk metallic glasses（BMGs）through the lateral-deformation,*** was found that the pre-exiting shear bands can further enhance the compressive plasticity of ductile *** to the serration analysis on the plastic deformation of the as-cast and the pre-deformed samples,the serration events in the stress-strain curves during deformation display a self-organized critical（SOC）*** with the as-cast BMGs,a larger power-law scaling exponent calculated based on serrated flow behaviors becomes larger for the pre-deformed BMGs,implying that the shear banding stability of BMGs is effectively *** should be caused by the pronounced interactions of shear bands during plastic deformation for the pre-deformed ***,by introducing a large amount of multiple shear bands into the glassy matrix,it also becomes easier for shear bands to propagate along the pre-existing shear bands,leading to a lower cut-off elastic energy density for the pre-deformed *** multiple shear bands with stronger interactions for the pre-deformed BMGs could provide a larger chance to activate the shear-band cracking but less local elastic energies are remained for the subsequent crack-linking.

关键词： Bulk metallic glass Shear band Serration Ductility Pre-deformation

Up-Hill Diffusion of Phase-Separated FeCu Melt by Molecular Dynamics Simulation

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Chinese Physics Letters 2017年第2期34卷 71-75页

作者： Wen-Chao Cui Chuan-Xiao Peng Yun Cheng kai-kai song Xue-Lian Li Zhen-Ting Zhang Sheng-Zhong Yuan Li Wang School of Mechanical&Electrical and Information Engineering Shandong UniversityWeihai 264209

Molecular dynamics simulation is performed to characterize the concentration fluctuation of FeCu melts during the liquid-liquid phase separation process, which undergoes the following stages： the formation of interconnected structure and its coarsening, migration and coagulation of droplets driven by the decreasing of potential energy. The up-hill diffusion happens at the early relaxation period in which Cu atoms in Fe-rich region are forced to move toward Cu-rich region by spinodal decomposition with 90~ Cu content in Cu-rich region and 95~o Fe content in Fe-rich region at temperature of 1500K. The higher diffusion rate of homogeneous atom can be observed at lower temperature, which is attributed to the larger potential energy difference between Cu-rich region and Fe-rich region. It also exhibits energy heterogeneity in the separated liquid. The domain size decreases sharply during the aggregation and coarsening of droplets, after that it keeps unchanged until the coagulation of droplets begins. The studies characterize concentration and energy heterogeneity of phase-separated liquid on the atomic scale.

关键词： Cu Fe

Repetitive traumatic brain injury–induced complement C1–related inflammation impairs long-term hippocampal neurogenesis

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Neural Regeneration Research 2025年第3期20卷 821-835页

作者： Jing Wang Bing Zhang Lanfang Li Xiaomei Tang Jinyu Zeng Yige song Chao Xu kai Zhao Guoqiang Liu Youming Lu Xinyan Li kai Shu Department of Neurosurgery Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanHubei ProvinceChina Department of Neurosurgery Shanxi Bethune HospitalShanxi Academy of Medical SciencesTongji Shanxi HospitalThird Hospital of Shanxi Medical UniversityTaiyuanShanxi ProvinceChina Department of Pathophysiology School of Basic Medicine and Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanHubei ProvinceChina Institute for Brain Research Wuhan Center of Brain ScienceHuazhong University of Science and TechnologyWuhanHubei ProvinceChina Department of Graduate Student Chongqing Medical UniversityChongqingChina Department of Basic Medicine School of Medical ScienceHubei University for NationalitiesEnshiHubei ProvinceChina Department of Anatomy School of Basic Medicine and Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanHubei ProvinceChina

Repetitive traumatic brain injury impacts adult neurogenesis in the hippocampal dentate gyrus,leading to long-term cognitive ***,the mechanism underlying this neurogenesis impairment remains *** this study,we established a male mouse model of repetitive traumatic brain injury and performed long-term evaluation of neurogenesis of the hippocampal dentate gyrus after repetitive traumatic brain *** results showed that repetitive traumatic brain injury inhibited neural stem cell proliferation and development,delayed neuronal maturation,and reduced the complexity of neuronal dendrites and *** with repetitive traumatic brain injuryalso showed deficits in spatial memory ***,following repetitive traumatic brain injury,neuroinflammation was enhanced in the neurogenesis microenvironment where C1q levels were increased,C1q binding protein levels were decreased,and canonical Wnt/β-catenin signaling was *** inhibitor of C1 reversed the long-term impairment of neurogenesis induced by repetitive traumatic brain injury and improved neurological *** findings suggest that repetitive traumatic brain injury–induced C1-related inflammation impairs long-term neurogenesis in the dentate gyrus and contributes to spatial memory retrieval dysfunction.

关键词： complement C1 dendrite dentate gyrus hippocampus neural stem cell neurogenesis neuroinflammation neurological function neuron traumatic brain injury

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基于社交网络的用户行为记忆性研究

微电子学与计算机 2017年第3期34卷 133-135,140页

作者：李凯凯宋礼鹏中北大学计算机与控制工程学院山西太原030051

为了研究用户访问社交网络时的记忆效应,分析了某高校师生用户对QQ空间和新浪微博这两个目前较主流的社交平台的访问记录,采用自相关函数来量化记忆性,发现在阵发周期内,个体用户和群体用户的行为数都服从幂律分布,因此,记忆性取决于同... 详细信息

为了研究用户访问社交网络时的记忆效应,分析了某高校师生用户对QQ空间和新浪微博这两个目前较主流的社交平台的访问记录,采用自相关函数来量化记忆性,发现在阵发周期内,个体用户和群体用户的行为数都服从幂律分布,因此,记忆性取决于同一阵发周期内相邻时间间隔的关联性,并从相邻时间间隔相关性的角度分析了用户在线行为的记忆性.研究结果表明,在同一个阵发周期内用户在线行为相邻时间间隔的比率为双帕累托分布,用户根据该比值的大小来增加或减少之后的登陆频率,实证数据研究与理论分析相吻合,证实了时间间隔中记忆性的存在.

关键词：社交网络时间间隔记忆性双帕累托分布相关性

Multilevel analysis of the central-peripheral-target organ pathway:contributing to recovery after peripheral nerve injury

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Neural Regeneration Research 2025年第10期20卷 2807-2822页

作者： Xizi song Ruixin Li Xiaolei Chu Qi Li Ruihua Li Qingwen Li kai-Yu Tong Xiaosong Gu Dong Ming Academy of Medical Engineering and Translational Medicine Tianjin UniversityTianjinChina Haihe Laboratory of Brain-Machine Interface and Human-Machine Fusion TianjinChina Department of Rehabilitation Tianjin University Tianjin HospitalTianjinChina Department of Hand Microsurgery Tianjin University Tianjin HospitalTianjinChina School of Exercise and Health Tianjin University of SportTianjinChina Department of Biomedical Engineering the Chinese University of Hong KongHong Kong Special Administrative RegionChina

Peripheral nerve injury is a common neurological condition that often leads to severe functional limitations and *** on the pathogenesis of peripheral nerve injury has focused on pathological changes at individual injury sites,neglecting multilevel pathological analysis of the overall nervous system and target *** has led to restrictions on current therapeutic *** this paper,we first summarize the potential mechanisms of peripheral nerve injury from a holistic perspective,covering the central nervous system,peripheral nervous system,and target *** peripheral nerve injury,the cortical plasticity of the brain is altered due to damage to and regeneration of peripheral nerves;changes such as neuronal apoptosis and axonal demyelination occur in the spinal *** nerve will undergo axonal regeneration,activation of Schwann cells,inflammatory response,and vascular system regeneration at the injury *** damage to target organs can occur,including skeletal muscle atrophy and sensory receptor *** then provide a brief review of the research advances in therapeutic approaches to peripheral nerve *** main current treatments are conducted passively and include physical factor rehabilitation,pharmacological treatments,cell-based therapies,and physical ***,most treatments only partially address the problem and cannot complete the systematic recovery of the entire central nervous system-peripheral nervous system-target organ ***,we should further explore multilevel treatment options that produce effective,long-lasting results,perhaps requiring a combination of passive(traditional)and active(novel)treatment methods to stimulate rehabilitation at the central-peripheral-target organ levels to achieve better functional recovery.

关键词： central nervous system central peripheral target organ multilevel pathological analysis nerve regeneration peripheral nerve injury peripheral nervous system target organs therapeutic approach

A novel flexible nerve guidance conduit promotes nerve regeneration while providing excellent mechanical properties

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Neural Regeneration Research 2025年第7期20卷 2084-2094页

作者： Tong Li Quhan Cheng Jingai Zhang Boxin Liu Yu Shi Haoxue Wang Lijie Huang Su Zhang Ruixin Zhang song Wang Guangxu Lu Peifu Tang Zhongyang Liu kai Wang Department of Orthopedics the Fourth Medical Center of Chinese PLA General HospitalBeijingChina Department of Training and Sports Medicine Characteristic Medical Center of Chinese People’s Armed Police ForceTianjinChina Medical School of Chinese PLA BeijingChina Key Laboratory of Bioactive Materials for the Ministry of Education College of Life SciencesNankai UniversityTianjinChina Department of Orthopedics Tianjin HospitalTianjinChina Department of Rehabilitation Medicine Er Quan Hospital of PAPWuxiJiangsu ProvinceChina

Autografting is the gold standard for surgical repair of nerve defects>5 mm in length;however,autografting is associated with potential complications at the nerve donor *** an alternative,nerve guidance conduits may be *** ideal conduit should be flexible,resistant to kinks and lumen collapse,and provide physical cues to guide nerve *** designed a novel flexible conduit using electrospinning technology to create fibers on the innermost surface of the nerve guidance conduit and employed melt spinning to align ***,we prepared disordered electrospun fibers outside the aligned fibers and helical melt-spun fibers on the outer wall of the electrospun fiber *** presence of aligned fibers on the inner surface can promote the extension of nerve cells along the *** helical melt-spun fibers on the outer surface can enhance resistance to kinking and compression and provide *** novel conduit promoted nerve regeneration and functional recovery in a rat sciatic nerve defect model,suggesting that it has potential for clinical use in human nerve injuries.

关键词： aligned fibers anti-kinking helical fibers nerve guidance conduit nerve regeneration peripheral nerve injury topological guidance

Genomic Landscape of Rare Codon Usage at Start Region in the Pacific Oyster Genome

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Journal of Ocean University of China 2023年第4期22卷 1041-1048页

作者： song kai School of Mathematics and Statistics Qingdao UniversityQingdao 266071China

Synonymous codons have different frequencies of usage in many *** on the frequency of usage,the codons can be divided into two groups,rare codons and abundant *** codons are found to be enriched at the start regions of genes,and it is assumed that these codons can reduce elongation speed of ***,the rare codon usage in different genomic regions of mollusks and their relationship with selective pressure has not been systematically *** this study,the patterns of rare codon usage are characterized at whole genome level,and their relationship with selective pressures is investigated in Crassostrea *** rare codons are enriched at the start regions of genes with high and medium expression levels,and their proportion is higher than those in the genes with low expression *** genes with longer coding sequences and more exon numbers have lower fraction of rare codons at start *** codons have lower level of nucleotide diversity and higher frequency of rare mutations at start *** work is the first comprehensive investigation of the relationships between rare codon usage and some intrinsic genetic factors in mollusca *** results suggest that the selective pressures play an important role in shaping the rare codon usage in the *** genome.

关键词： rare codons selective pressures nucleotide diversity Crassostrea gigas