检索结果-南通市图书馆

Manipulating mechanical properties of graphene/Al composites by an in-situ synthesized hybrid reinforcement strategy

引用

Journal of Materials Science & Technology 2022年第28期123卷 13-25页

作者： lizhuang yang Bowen Pu Xiang Zhang Junwei Sha Chunnian He Naiqin Zhao School of Materials Science and Engineering Tianjin Key Laboratory of Composite and Functional MaterialsTianjin UniversityTianjin 300072China Joint School of National University of Singapore and Tianjin University International Campus of Tianjin UniversityBinhai New CityFuzhou 350207China Collaborative Innovation Center of Chemical Science and Engineering(Tianjin) Tianjin 300072China Key Laboratory of Advanced Ceramics and Machining Technology Ministry of EducationTianjin UniversityTianjin 300072China

The structural deterioration caused by the relatively weak out-of-plane bending stiffness and the chemically-active edge area of graphene limits its outperformance in strengthening for Al matrix composites(AMCs).Introducing one-dimensional(1D)carbon nanotubes(CNTs)to graphene/metal system is one of the promised strategies to complement the weakness of 2D graphene and make full use of the outstanding intrinsic properties of the both reinforcements.To date,such synergistic strengthening and toughening mechanisms are largely unknown.In this study,AMCs reinforced by a novel hybrid reinforcement,i.e.,graphene nanosheets decorated with Cu nanoparticles and CNTs(Cu@GNS-CNTs),are fabricated by an in-situ synthesis method.The combined contrast experiments validated that the organically integrated reinforcing structure promotes the intrinsic load bearing capacity of GNS and the strain hardening capability of the Al matrix simultaneously.As a result,the composites achieved excellent tensile strength and uniform elongation with almost no loss.The strengthening mechanism originated primarily from the hybrid reinforcement exhibits superior load-transfer,fracture inhibition and dislocation storage capability by controlling the interface reaction to construct an effective interface structure without damaging the reinforcement.Our work identifies a promising structural modification strategy for 2D materials and provides mechanistic insights into the synergistic strengthening effect of graphene/CNTs hybrid reinforcement.

关键词： Metal-matrix composites(MMCs) Mechanical properties Graphene Synergistic strengthening Interface

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Toughening Effects through Optimizing Cell Structure and Deformation Behaviors of Al–Mg Foams

引用

Acta Metallurgica Sinica(English Letters) 2022年第12期35卷 2014-2026页

作者： Hao Yu Xudong yang Weiting Li Xudong Rong Siyuan Guo Lishi Ma lizhuang yang Junwei Sha Naiqin Zhao Tianjin Key Laboratory of Composite and Functional Materials School of Materials Science and EngineeringTianjin UniversityTianjin 300350China Sino-European Institute of Aviation Engineering Civil Aviation University of ChinaTianjin 300300China School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China Key Laboratory of Advanced Ceramics and Machining Technology Ministry of EducationTianjin 300350China

As widely used protective materials,the application of Al foams is still limited by their low intrinsic mechanical properties caused by the brittleness of struts.The introduction of Mg is recently demonstrated effective to improve the mechanical performance of Al foams;however,the mechanism of Mg modification is still not clear.In this work,Al-Mg foams are developed through a powder metallurgy process with excellent compression performance and high energy absorption capacity.The effects of Mg modification on the cell structure,toughness,and deformation behavior are investigated systematically.As a result,the small cell size of~1.8 mm and the high sphericity of 0.92 are achieved with 5% of Mg addition,delivering high compression stress of 8.5±0.43 MPa and energy absorption capacity of 6.9±0.36 MJ/m^(3),simultaneously.The synergistic mechanism for the improved mechanical performance is also demonstrated to be the combination of stress transfer and plastic deformation behavior of cells.The results provide a new strategy to develop high-performance foam materials by improving toughness and further promote the practical application.

关键词： Powder metallurgy Aluminum foam Al-Mg alloy Plastic deformation Cell structure

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Si-Assisted Solidification Path and Microstructure Control of 7075 Aluminum Alloy with Improved Mechanical Properties by Selective Laser Melting

引用

Acta Metallurgica Sinica(English Letters) 2022年第9期35卷 1424-1438页

作者： Junwei Sha Meixian Li lizhuang yang Xudong Rong Bowen Pu Dongdong Zhao Simi Sui Xiang Zhang Chunnian He Jianglin Lan Naiqin Zhao School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials Tianjin UniversityTianjin300350China Collaborative Innovation Center of Chemical Science and Engineering Tianjin300350China Key Laboratory of Advanced Ceramics and Machining Technology Ministry of EducationTianjin300350China Central Iron and Steel Research Institute(CISRI) Beijing100081China

The construction and application of traditional high-strength 7075 aluminum alloy(Al7075) through selective laser melting(SLM) are currently restricted by the serious hot cracking phenomenon. To address this critical issue, in this study, Si is employed to assist the SLM printing of high-strength Al7075. The laser energy density during SLM is optimized, and the eff ects of Si element on solidification path, relative density, microstructure and mechanical properties of Al7075 alloy are studied systematically. With the modified solidification path, laser energy density, and the dense microstructure with refined grain size and semi-continuous precipitates network at grain boundaries, which consists of fine Si, β-MgSi, Q-phase and θ-AlCu, the hot cracking phenomenon and mechanical properties are eff ectively improved. As a result, the tensile strength of the SLM-processed Si-modified Al7075 can reach 486 ± 3 MPa, with a high relative density of ~ 99.4%, a yield strength of 291 ± 8 MPa, fracture elongation of(6.4 ± 0.4)% and hardness of 162 ± 2(HV) at the laser energy density of 112.5 J/mm~3. The main strengthening mechanism with Si modification is demonstrated to be the synergetic enhancement of grain refinement, solution strengthening, load transfer, and dislocation strengthening. This work will inspire more new design of high-strength alloys through SLM.

关键词： Selective laser melting(SLM) 7075 aluminum alloy High-strength alloy Microstructure control Solidification path

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Copper-Coated Graphene Nanoplatelets-Reinforced Al–Si Alloy Matrix Composites Fabricated by Stir Casting Method

引用

Acta Metallurgica Sinica(English Letters) 2021年第1期34卷 111-124页

作者： Xiaoqi Han lizhuang yang Naiqin Zhao Chunnian He School of Materials Science and Engineering and Tianjin Key Laboratory of Composite and Functional Materials Tianjin UniversityTianjin 300072China Joint School of National University of Singapore and Tianjin University International Campus of Tianjin UniversityBinhai New CityFuzhou 350207China Collaborative Innovation Center of Chemical Science and Engineering(Tianjin) Tianjin 300072China Key Laboratory of Advanced Ceramics and Machining Technology Ministry of EducationTianjin UniversityTianjin 300072China

In this study,Cu nanoparticles-coated graphene nanoplatelets(Cu-NPs@GNPs)were synthesized by a simple in situ method with the assistance of Na Cl templates and used for reinforcing Al–10 Si composites through stir casting process.The experimental results showed that the coating of Cu-NPs on the GNPs could compromise the density mismatch between GNPs and metal matrix and eff ectively hinder the float of GNPs during stirring.The reaction of Cu-NPs and Al matrix could protect the structural integrity of GNPs as well as improve the interfacial wettability between GNPs and the matrix,thus promoting the uniform dispersion of GNPs in the composites.As a result,the as-prepared 0.5 wt%Cu-NPs@GNPs/Al–10 Si composite exhibited a tensile strength of 251 MPa(45%higher than the Al–10 Si)with a total elongation of 15%.The strengthening eff ects were mainly attributed to the following three reasons:Firstly,the Cu-NPs coating improved the interfacial bonding between GNPs and Al matrix which promoted the load transfer from the matrix to the GNPs.Secondly,the nanoscale Al 2 Cu formed by the reaction of Cu-NPs and Al matrix played a role in precipitation strengthening.Thirdly,GNPs refined the silicon phases and improved the monolithic performances of the composites.

关键词： Al–Si alloy Graphene Stir casting Wettability Si phase refinement

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

胸椎T_(10)骨肿瘤转移不同位置生物力学特性的三维有限元分析

引用

中国组织工程研究 2024年第36期28卷 5759-5765页

作者：夏国仁余浩姜世峰彭新伏晓陈琦杨立状王腾飞李海中国科学院合肥肿瘤医院安徽省合肥市230000 中国科学院合肥物质研究院安徽省合肥市230000

背景:随着检查技术的革新,不同分期脊柱转移瘤患者逐年增多,经皮椎体成形是脊柱转移瘤重要的治疗手段,但其治疗不同分期、不同活动方式肿瘤的术后生物力学疗效尚未见报道。目的:基于三维有限元模型模拟胸椎T_(10)骨肿瘤转移不同位置的... 详细信息

背景:随着检查技术的革新,不同分期脊柱转移瘤患者逐年增多,经皮椎体成形是脊柱转移瘤重要的治疗手段,但其治疗不同分期、不同活动方式肿瘤的术后生物力学疗效尚未见报道。目的:基于三维有限元模型模拟胸椎T_(10)骨肿瘤转移不同位置的应力及位移情况。方法:根据1例30岁健康男性胸椎三维CT扫描数据,采用Mimics软件构建胸椎(T_(9)-T_(11))的三维几何模型,包括肋骨、韧带及椎间盘。模拟被胸椎转移瘤侵袭的T_(9)-T_(11)椎体及其后胸椎不同部位的三维模型,包括椎体结构完整的对照组,单侧转移累及椎体区(实验组1),单侧转移累及椎体和椎弓根区(实验组2),单侧转移累及椎体、椎弓根和横突区(实验组3),双侧转移累及椎体、椎弓根和横突区(实验组4)。利用Abaqus软件创建三维有限元模型,对负重、屈曲、伸展、旋转工况下VonMises应力分布及模型的位移情况进行分析。结果与结论:①在对不同实验组加载点在负重、屈曲、伸展、旋转工况下最大总位移的研究中,随着转移瘤侵袭部位及侵袭面的增多,加载点的总位移在增大,整体刚度降低,尤其实验组4加载点的总位移最大;②在屈曲工况下椎体、椎弓根破坏后明显增加最大Von Mises应力值,而在此基础上增加胸肋关节破坏,其最大Von Mises应力值基本不变;③有限元分析并模拟骨肿瘤模型的基础上,将骨水泥区域的单元设置为一个单独的set集合,后将骨水泥区域设置为对应的材料属性以模拟骨水泥填充,结果发现,负重、屈曲、伸展、旋转工况下最大总位移均小于各实验组;④模拟经皮椎体成形治疗后患者在负重、屈曲、伸展、旋转工况下的最大应力值相较于骨肿瘤模型大幅度降低;⑤提示基于胸椎T_(9)-T_(11)的三维有限元模型构建有利于对胸椎骨肿瘤转移生物力学特性的研究,并能够在胸椎骨肿瘤转移模型的基础上准确模拟经皮椎体成形后加载点在不同工况下的总位移及最大VonMises应力情况。

关键词：脊柱转移瘤经皮椎体成形骨水泥有限元模型生物力学分析

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

乳腺癌患者化疗早期大脑皮层表面形态学改变和癌症相关疲劳变化的关系:基于表面形态测量方法

引用

磁共振成像 2024年第2期15卷 48-55页

作者：周燕飞李竞伏晓袁文娟王宏志杨立状李海中国科学院合肥肿瘤医院医学影像中心合肥230000 中国科学院合肥物质科学研究院健康与医学技术研究所合肥230031 中国科学院合肥肿瘤医院乳腺中心合肥230000

目的研究乳腺癌患者化疗早期大脑皮层表面形态改变及其与癌症相关疲劳(cancer-related fatigue,CRF)变化的关系。材料与方法选取25例首诊女性乳腺癌患者,分别在手术后化疗前(化疗开始前一周内)、化疗期间(化疗第二个周期结束后两周内)... 详细信息

目的研究乳腺癌患者化疗早期大脑皮层表面形态改变及其与癌症相关疲劳(cancer-related fatigue,CRF)变化的关系。材料与方法选取25例首诊女性乳腺癌患者,分别在手术后化疗前(化疗开始前一周内)、化疗期间(化疗第二个周期结束后两周内)进行简易疲乏量表(Brief Fatigue Inventory,BFI)、汉密尔顿抑郁量表(Hamilton Depression Scale,HAMD)和汉密尔顿焦虑量表(Hamilton Anxiety Scale,HAMA)等神经心理学测试和颅脑磁共振3D-T1加权数据采集。同期招募年龄匹配的健康女性作为对照组,并在匹配的时间间隔内使用同样的评估方式进行临床资料和磁共振数据收集。基于表面的形态学方法(surface-based morphometry,SBM),采用统计参数映射分析12(statistical parametric mapping,SPM 12)软件包中的计算解剖工具箱12(computational anatomy toolbox,CAT 12)对所有受试者进行大脑皮层表面形态学分析,采用SPSS 26.0分析乳腺癌患者化疗期间皮层表面形态改变的脑区与CRF纵向变化之间的相关性。结果与化疗前相比,乳腺癌患者在化疗早期的CRF、抑郁、焦虑测量评分差异有统计学意义(P<0.05);化疗期间乳腺癌患者皮层表面形态的皮层厚度、沟深、分形维数、皮质褶皱指数参数值较化疗前发生了改变,差异有统计学意义(P<0.05):顶叶(双侧楔前叶、右侧缘上回、右侧中央后回)、枕叶(双侧楔叶)的皮层厚度减少,顶叶(双侧顶下小叶、右侧缘上回及顶上小叶)、颞叶(右侧梭状回、颞上回及颞下回)、枕叶(双侧枕外侧回、右侧楔叶、右侧距状旁回)的沟深减少,左侧枕叶(枕外侧回)、右侧额叶(额上回、前中额叶及额下回)、右侧顶叶(缘上回及顶下小叶)的分形维数减少,左侧枕叶(枕外侧回及楔叶)、右侧顶叶(缘上回、顶上小叶及顶下小叶)、右侧颞叶(颞中回、颞下回及颞上回后部)的皮层褶皱指数增大;与化疗前相比,化疗早期右前中额叶分形维数的改变与CRF的纵向变化呈负相关(r=-0.628,P=0.001)。结论乳腺癌患者的皮层表面形态在化疗早期即可发生改变,并与CRF的变化相关。

关键词：乳腺癌化疗癌症相关疲劳大脑皮层磁共振成像

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

结构知识错误而非奖励敏感性不足解释了衰老过程中的元控制减弱

引用

中国科学技术大学学报 2023年第12期53卷 14-22,I0003,I0009页

作者：左肇煜杨立状李海中国科学院合肥物质科学研究院医学物理与技术安徽省重点实验室健康与医学技术研究所安徽合肥230031 中国科学技术大学安徽合肥230026 中国科学院合肥肿瘤医院安徽合肥230031

人们根据成本-效益权衡原则灵活地调整无模型(习惯性)和基于模型(目标导向)策略的权重,这种能力被称为元控制。最近的研究表明:老年人的元控制灵活性减弱。然而,老年人的元控制缺陷究竟源于认知因素还是动机因素仍然存在争议。本研究结... 详细信息

人们根据成本-效益权衡原则灵活地调整无模型(习惯性)和基于模型(目标导向)策略的权重,这种能力被称为元控制。最近的研究表明:老年人的元控制灵活性减弱。然而,老年人的元控制缺陷究竟源于认知因素还是动机因素仍然存在争议。本研究结合瞳孔测量记录和具有不同任务结构及奖励水平的序列决策任务对这一问题进行了研究。研究结果复现了之前的研究发现,即老年人采用了更少的基于模型策略,并且在奖励水平改变时元控制灵活性不足。然而,瞳孔分析表明了老年人对奖励水平的敏感性。口头报告分析揭示了老年人的任务结构知识存在个体差异,结构知识较好的亚组与年轻人表现出相似的模式。计算仿真证明结构知识不准确会妨碍元控制。以上结果表明,老年人元控制的灵活性不足并非由于缺乏动机,而是结构知识不准确。

关键词：决策元控制强化学习衰老

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Excessive Use of Twitter among College Students in the UK:Validation of the Microblog Excessive Use Scale,Culture Effect,and Relationship to Social Interaction and Loneliness

Excessive Use of Twitter among College Students in the UK:Va...

引用

中国心理学会发展心理专业委员会第十三届学术年会

作者： Juan Hou Yamikani Ndasauka Ying Wang lizhuang yang Zhiyu yang Andreas J. Fallgatter Yan Kong Xiaochu Zhang Department of Philosophy Anhui University School of Humanities and Social Science University of Science and Technology of China CAS Key Laboratory of Brain Function and Disease and School of Life Science University of Science and Technology of China Department of Psychiatry University of Tübingen Graduate School LEAD University of Tübingen Centers for Biomedical Engineering University of Science & Technology of China Center of Medical Physics and Technology Hefei Institutes of Physical Science CAS

Microblogging on sites like Twitter is a growing and popular trend among young people.Apparently,some users of these microblogs exhibit addiction-like symptoms.Until recently,there was no psychometric scale to measure the excessive use of Twitter.The development of the Microblog Excessive Use Scale(MEUS)proved a positive step in assessing this phenomenon.In this study,we used the MEUS to assess the excessive use of Twitter in a sample of 256 college students(53.1%Female and mean age of 21.4 years)in the UK.Confirmatory factor analysis(CFA),calculation of criterion-related and concurrent validity and reliability were performed to assess the scale’s psychometric properties.The MEUS was found to be a valid instrument for assessing excessive use of Twitter in UK college students.Further,the present study also revealed some similarities and differences between excessive use of Twitter in UK and excessive use of Weibo in China,which may be explained by culture differences.In addition,excessive use of Twitter was found associated with loneliness and this relationship was mediated by real life social interactions.Implications for these findings are discussed.

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Transforming brain signals related to value evaluation and self-control into behavioural choices

Transforming brain signals related to value evaluation and s...

引用

中国神经科学学会第十二届全国学术会议

作者： Rujing Zha Junjie Bu Zhengde Wei Long Han Pengyu Zhang Jiecheng Ren Ying Wang lizhuang yang Xiaochu Zhang Key Laboratory of Brain Function and Disease Chinese Academy of Sciences School of Life Sciences University of Science ＆ Technology of China

According to decision theory, value evaluation and self-control processes are both critical while making behavioural choices. However, the evidence that links these two processes to behavioural choices in intertemporal decision making remains elusive. As the ventromedial prefrontal cortex（vmPFC）, striatum, and dorsolateral prefrontal cortex（dl PFC） have been related to these two processes, we focused on these three regions. We employed functional magnetic resonance imaging during a delayed discounting task using a relatively large sample size and three independent samples. In Experiment Ⅰ, we found that the vm PFC and dl PFC, but not the striatum, could determine choices using spatial activity patterns, and that the left dl PFC showed a significant functional connectivity with the vm PFC, but not the striatum, when making decisions. These results could be replicated in Experiment Ⅱ. In Experiment Ⅲ, the choice decoding accuracy in the vmPFC and dl PFC was lower in patients with addiction than in cognitively normal participants. Together, our findings may provide neural evidence to support the hypothesis that value evaluation and self-control processes both guide the choices made by normal people, and provide potential neural targets for the diagnosis and treatment of impulsivity-related brain disorders such as addiction.

关键词： Intertemporal decision making value evaluation self-control choice multivoxel pattern analysis fMRI

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Recent progress in thermodynamic and kinetics modification of magnesium hydride hydrogen storage materials

引用

Materials Reports(Energy) 2024年第1期4卷 3-22页

作者： Yafei Liu Yusang Guo Yaru Jiang lizhuang Feng Yu Sun Yijing Wang Key Laboratory of Advanced Energy Materials Chemistry Ministry of EducationRenewable Energy Conversion and Storage CenterCollege of ChemistryCollaborative Innovation Center of Chemical Science and Engineering(Tianjin)Nankai UniversityTianjin300071PR China

Hydrogen energy has emerged as a pivotal solution to address the global energy crisis and pave the way for a cleaner,low-carbon,secure,and efficient modern energy system.A key imperative in the utilization of hydrogen energy lies in the development of high-performance hydrogen storage materials.Magnesium-based hydrogen storage materials exhibit remarkable advantages,including high hydrogen storage density,cost-effectiveness,and abundant magnesium resources,making them highly promising for the hydrogen energy sector.Nonetheless,practical applications of magnesium hydride for hydrogen storage face significant challenges,primarily due to their slow kinetics and stable thermodynamic properties.Herein,we briefly summarize the thermodynamic and kinetic properties of MgH2,encompassing strategies such as alloying,nanoscaling,catalyst doping,and composite system construction to enhance its hydrogen storage performance.Notably,nanoscaling and catalyst doping have emerged as more effective modification strategies.The discussion focuses on the thermodynamic changes induced by nanoscaling and the kinetic enhancements resulting from catalyst doping.Particular emphasis lies in the synergistic improvement strategy of incorporating nanocatalysts with confinement materials,and we revisit typical works on the multi-strategy optimization of MgH2.In conclusion,we conduct an analysis of outstanding challenges and issues,followed by presenting future research and development prospects for MgH2 as hydrogen storage materials.

关键词： Magnesium hydride Thermodynamics and kinetics Catalyst doping Nanostructures Hydrogenation and dehydrogenation

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：