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Effects of electromagnetic vibration on the structure and mechanical properties of Al-6%Si alloy during directional solidification

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Acta Metallurgica Sinica(English Letters) 2009年第1期22卷 35-39页

作者： Jianbo YU Zhongming REN weili REN Kang deng Yunbo ZHONG Department of Materials Science and Engineering Shanghai University Shanghai 200072 China

The effects of electromagnetic vibration on the grain refinement in directional solid- ification were investigated. It was found that the electromagnetic vibration applied in the melt not only can refine grains remarkably but also can enhance both tensile strength and ductility values of Al-6%Si alloy. SEM graphs show that coarse dendrite structure was broken up into a somewhat globular structure, and the morphology of eutectic silicon was changed from flaky to fibrous under electromagnetic vibration treatment. The refine mechanism under electromagnetic vibration was discussed.

关键词： Electromagnetic vibration Grain refinement Directional solidification Mechanical property

Tertiary orientation structures enhance the piezoelectricity of MXene/PVDF nanocomposite

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Nano Research 2024年第6期17卷 5629-5635页

作者： Yong Ao Tao Yang Guo Tian Shenglong Wang Tianpei Xu Lin deng Jieling Zhang Lihua Tang weili deng Long Jin Weiqing Yang Key Laboratory of Advanced Technologies of Materials(Ministry of Education) School of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China Department of Mechanical Engineering The University of AucklandAuckland 1010New Zealand Research Institute of Frontier Science Southwest Jiaotong UniversityChengdu 610031China

With the increasing demand for flexible piezoelectric sensor components,research on polyvinylidene fluoride(PVDF)based piezoelectric polymers is mounting ***,the low dipole polarization and disordered polarization direction presented in PVDF hinder further improvement of piezoelectric ***,we constructed an oriented tertiary structure,consisting of molecular chains,crystalline region,and MXene sheets,in MXene/PVDF nanocomposite via a temperature-pressure dual-field regulation *** highly oriented PVDF molecular chains form approximately 90%of theβ*** addition,the crystalline region structure with long-range orientation achieves out of plane polarization *** parallel orientation arrangement of MXene effectively enhances the piezoelectric performances of the nanocomposite,and the current output of the device increases by nearly 23 *** high output device is used to monitor exercise action,exploring the potential applications in wearable electronics.

关键词： flexible sensor piezoelectric MXene/polyvinylidene fluoride(PVDF)nanocomposite orientation structures

MXene based mechanically and electrically enhanced film for triboelectric nanogenerator

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Nano Research 2021年第12期14卷 4833-4840页

作者： Yuyu Gao Guoxu Liu Tianzhao Bu Yaoyao Liu Youchao Qi Yanting Xie Shaohang Xu weili deng Weiqing Yang Chi Zhang CAS Center for Excellence in Nanoscience Beijing Key Laboratory of Micro-nano Energy and SensorBeijing Institute of Nanoenergy and Nanosystems Chinese Academy of SciencesBeijing101400China Key Laboratory of Advanced Technologies of Materials(Ministry of Education) School of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu610031China School of Nanoscience and Technology University of Chinese Academy of SciencesBeijing100049China Center on Nanoenergy Research School of Physical Science and TechnologyGuangxi UniversityNanning530004China

The development of triboelectric nanogenerator(TENG)technology which can directly convert ambient mechanical energy into electric energy may affect areas from green energy harvesting to emerging wearing ***,the material of triboelectric layer is critical to the mechanical robustness and electrical output characteristics of the ***,a MXene enhanced electret polytetrafluoroethylene(PTFE)film with a high mechanical property and surface charge density is *** MXene/PTFE composite film was synthesized by spraying and annealing *** the doping of MXene,the crystallinity of composite film could be tuned,leading to an enhancement in the tensile property of 450%and reducing the wear volume about 80%in the friction ***,the as-fabricated TENG with this composite film outputs 397 V of open-circuit voltage,21µA of short-circuit current,and 232 nC of transfer charge quantity,which are 4,6,and 6 times higher than that of the TENG made by pure PTFE film,***,this work provides a creative strategy to simultaneously improve the mechanical property and electrical performance of the TENGs,which have great potential in improving device stability under a complex mechanical environment.

关键词： MXene polytetrafluoroethylene(PTFE) mechanically and electrically enhanced triboelectric layer triboelectric nanogenerator

Gradient CNT/PVDF piezoelectric composite with enhanced force-electric coupling for soccer training

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Nano Research 2023年第8期16卷 11312-11319页

作者： Wanghong Zeng weili deng Tao Yang Shenglong Wang Yue Sun Jieling Zhang Xiarong Ren Long Jin Lihua Tang Weiqing Yang Key Laboratory of Advanced Technologies of Materials(Ministry of Education) School of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China Department of Mechanical and Mechatronics Engineering University of AucklandAuckland 1010New Zealand Research Institute of Frontier Science Southwest Jiaotong UniversityChengdu 610031China

Real-time monitoring of ball–shoe interactions can provide essential information for high-quality instruction in personalized soccer training,yet existing monitoring systems struggle to reflect specific forces,loci,and durations of ***,we design a self-powered piezoelectric sensor constructed by the gradient carbon nanotube/polyvinylidene fluoride(CNT/PVDF)composite to monitor the interactions between the ball and the ***-dimensional Raman mapping demonstrates the gradient structure of CNT/PVDF prepared by programmable electrospinning combined with a hot *** from the synergistic effect of local polarization caused by the enrichment of CNT and the reduced diffusion of silver patterns in gradient structure,the as-prepared composite exhibits enhanced force-electric coupling with an excellent sensitivity of 80 mV/N and durability over 15,000 *** this basis,we conformally attach a 3×3 sensor array to a soccer shoe,enabling real-time acquisition of kick position and contact force,which could provide quantitative assessment and personalize guidance for the training of soccer *** self-powered piezoelectric sensor network system offers a promising paradigm for wearable monitoring under strong impact forces.

关键词： mechanical and electrical performance pressure sensor carbon nanotube/polyvinylidene fluoride(CNT/PVDF)composite soccer training

Body-area sensor network featuring micropyramids for sports healthcare

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Nano Research 2023年第1期16卷 1330-1337页

作者： Shenglong Wang weili deng Tao Yang Guo Tian Da Xiong Xiao Xiao Hongrui Zhang Yue Sun Yong Ao Junfeng Huang Jun Chen Weiqing Yang Key Laboratory of Advanced Technologies of Materials(Ministry of Education) School of Materials Science and EngineeringSouthwest Jiao tong UniversityChengdu 610031China Department of Bioengineering University of CaliforniaLos AngelesLos AngelesCA 90095USA

Monitoring physiological signals of the human body can provide extremely important information for sports healthcare,preventing injuries and providing efficient guidance for individual ***,the signals related to human healthcare involve both subtle and vigorous signals,making it difficult for a sensor to satisfy the full-scale monitoring at the same ***,a novel conductive elastomer featuring homogeneously micropyramid-structured PDMS/CNT composite is used to fabricate highperformance piezoresistive sensors by a drop-casting *** from the significant increase in the contact area of microstructure during deformation,the flexible sensor presents a broad detection range(up to 185.5 kPa),fast response/recovery time(44/13 ms),ultrahigh sensitivity(242.4 kPa–1)and excellent durability over 8,000 *** a proof of concept,the as-fabricated pressure sensor can be used for body-area sports healthcare,and enable the detection of full-scale pressure *** the fabulous sensing performance,the sensor may potentially become promising in personal sports healthcare and telemedicine monitoring.

关键词： pressure sensor pyramidal microstructure sports healthcare sensor network broad detection range high sensitivity

From high-yield Ti3AlCN ceramics to high-quality Ti3CNTx MXenes through eliminating Al segregation

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Chinese Chemical Letters 2020年第4期31卷 1044-1048页

作者： Ningjun Chen Haichao Huang Zhong Xu Yanting Xie Da Xiong Xiang Chu Bingni Gu Bo Zheng weili deng Haitao Zhang Weiqing Yang Key Laboratory of Advanced Technologies of Materials Ministry of EducationSchool of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China State Key Laboratory of Traction Power Southwest Jiaotong UniversityChengdu 610031China

Ti3CNTx MXenes with unique electrical conductivity can be widely applied for supercapacitors and electromagnetic ***,its relatively low-yield quaternary nitrogen-containing Ti3AlCN ce ramics precursor(less than 50%),due to the inevitable Al segregation during the synthesizing process,significantly hindered its widely commercial ***,we employed the controllable AlNoversaturation precursor strategy to precisely tune the phase transition point of quaternary Ti3AlCN ceramics to obtain high-yield Ti3 AlCN precursor for the purpose of high conductivity Ti3 CNTx *** energy dispersive X-ray spectrometer(XRD)with X-ray photoelectron spectroscopy(XPS)characterizations,the yield of the quaternary nitrogen-containing Ti3 AlCN ceramics was evidently proved to be up to 70%,which is 1.4 times than that of previously reported *** relatively highyield quaternary Ti3AlCN is mainly ascribed to the elimination of Al *** on it,we further developed accordion-like two-dimensional(2D)MXene via hydrofluoric acid etch and vacuum *** novel accordion-like 2D Ti3CNTx MXene possesses high electrochemical capacitive properties(209 F/g).Therefore,this controllable AlN-oversaturation precursor strategy will pave a way to exploit costly high-yield MAX ceramics precursor for high conductivity MXenes and also play a powerful role in promoting their practical applications including electrical and magnetic engineering fields.

关键词： Al segregation High-yield Ti3AlCN MAX phase Ti3CNTx MXenes Supercapacitors

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超声波在轮轨材料中传播的数值模拟

西南交通大学学报 2012年第5期47卷 836-841,848页

作者：邓维礼永远西南交通大学材料科学与工程学院四川成都610031

为进一步研究超声波的声场分布特性,增强超声波在高速铁路中轮轨探伤、列车安全监测等方面的应用,设计了轮轨有限元模型,模拟了不同声源尺寸下不同频率超声波在轮轨材料中传播时的声场分布,绘制了声源轴线上的声压分布曲线,在此基础上,... 详细信息

为进一步研究超声波的声场分布特性,增强超声波在高速铁路中轮轨探伤、列车安全监测等方面的应用,设计了轮轨有限元模型,模拟了不同声源尺寸下不同频率超声波在轮轨材料中传播时的声场分布,绘制了声源轴线上的声压分布曲线,在此基础上,分析了超声波近场长度、指向性、超声波频率及声源大小之间的关系.研究结果表明:在相同声源直径的模型中,频率为1.0 MHz的超声波近场长度最长,指向性最好;相同超声频率的模型中,声源直径为40 mm的超声波近场长度最长,指向性最好.

关键词：超声波传播轮轨数值模拟

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基于超声技术轮轨接触状态监测的数值模拟

西南交通大学学报 2014年第6期49卷 1073-1077页

作者：邓维礼肖南永远西南交通大学材料科学与工程学院四川成都610031

为了实时监测列车行车状态,保障其安全运行,提出利用超声技术监测轮轨接触状态的方法.引入W-M分形函数对粗糙的轮轨表面进行数学描述,运用多物理场耦合软件构建了超声技术监测轮轨接触状态的有限元模型.利用该模型,用本文提出的方法对... 详细信息

为了实时监测列车行车状态,保障其安全运行,提出利用超声技术监测轮轨接触状态的方法.引入W-M分形函数对粗糙的轮轨表面进行数学描述,运用多物理场耦合软件构建了超声技术监测轮轨接触状态的有限元模型.利用该模型,用本文提出的方法对界面粗糙度、介质层种类及厚度等因素进行了模拟,获得了相应条件下轮轨接触界面的反射声压.算例仿真结果表明:通过监测轮轨接触界面超声反射波的声压变化来判定轮轨接触状态的方法是有效可行的;当超声波频率为14 MHz时,轮轨表面粗糙度的区分度最好;当超声频率大于14 MHz时,对第三介质层厚度有较好的区分度;当超声波频率恒定且第三介质层厚度足够大时,超声反射声压级趋于恒定值102 d B.

关键词：轮轨接触状态监测数值模拟

Erratum to:Tertiary orientation structures enhance the piezoelectricity of MXene/PVDF nanocomposite

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Nano Research 2024年第6期17卷 5761-5761页

In the first page of the original version of this paper,the Received date should be“10 October 2023”instead of“10 October 2013”.

关键词： Tertiary orientation MXene