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Dual-compressed photoacoustic single-pixel imaging

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National science Review 2023年第1期10卷 187-195页

作者： Yuning Guo Baowen Li Xiaobo Yin department of Mechanical engineering University of Colorado department of Material science and engineering Department of Physics Shenzhen Institute for Quantum Science and Engineering Southern University of Science and Technology materials science and engineering Program University of Colorado

Photoacoustic imaging,an acoustic imaging modality with potentially optical resolution in an optical turbid medium,has attracted great attention.However,the convergence of wavefront optimization and raster scanning in computational photoacoustic imaging leads to the challenge of fast mapping,especially for a spatial resolution approaching the acoustic deep-subwavelength regime.As a sparse sampling paradigm,compressive sensing has been applied in numerous fields to accelerate data acquisition without significant quality losses.In this work,we propose a dual-compressed approach for photoacoustic surface tomography that enables high-efficiency imaging with 3D spatial resolution unlimited by the acoustics in a turbid environment.The dual-compressed photoacoustic imaging with single-pixel detection,enabled by spatially optical modulation with synchronized temporally photoacoustic coding,allows decoding of the fine optical information from the modulated acoustic signal even when the variance of original photoacoustic signals is weak.We perform a proof-of-principle numerical demonstration of dual-compressed photoacoustic imaging, that resolves acoustic sub-acoustic-wavelength details with a significantly reduced number of measurements,revealing the potential for dynamic imaging.The dual-compressed concept,which transforms unobtrusive spatial difference into spatio-temporal detectable information,can be generalized to other imaging modalities to re alize efficient,high-spatial-resolution imaging.

关键词： photoacoustic imaging compressive sensing single-pixel imaging surface tomography

以多阶段和非等温为特征的新型铝合金热处理方法综述

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Journal of Central South University 2023年第9期30卷 2833-2866页

作者：冯迪李鑫迪张新明刘胜胆王经涛刘瑛 department of materials science and engineering Jiangsu University of Science and TechnologyZhenjiang 212003China School of materials science and engineering Central South UniversityChangsha 410083China department of materials science and engineering Nanjing University of Science and TechnologyNanjing 210094China

预备热处理和最终热处理在铝合金产品的生产制备中都发挥着不可替代的作用。合金成分的均匀程度、弥散相的尺寸及其与基体的共格关系、再结晶晶粒的大小和长径比、溶质元素的过饱和度和时效沉淀相的特征等都直接决定了材料的力学性能、... 详细信息

预备热处理和最终热处理在铝合金产品的生产制备中都发挥着不可替代的作用。合金成分的均匀程度、弥散相的尺寸及其与基体的共格关系、再结晶晶粒的大小和长径比、溶质元素的过饱和度和时效沉淀相的特征等都直接决定了材料的力学性能、耐腐蚀性能和可加工性。在工程应用中,由于产品尺寸的影响,涉及加热和/或冷却过程的非等温现象是不可避免的。因此,具有工程适用性的新型热处理技术是固态相变理论得以实现的必要延伸。本文以AlZnMg(Cu)、AlMgSi和AlCu(Li)等典型变形铝合金为研究对象,综述了其均匀化、固溶和时效技术的研究现状,重点归纳和总结了新型热处理技术的多阶段热处理和非等温热处理。

关键词：变形铝合金多阶段热处理非等温热处理均匀化固溶时效

基于非对称PVA/墨水/PE双层膜的光驱动柔性致动器和多功能传感器

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science China materials 2023年第12期66卷 4782-4793页

作者：吴凤林晓莹许雨倩章迪何韵晴刘明贤 department of materials science and engineering College of Chemistry and Materials ScienceJinan UniversityGuangzhou 511443China

聚乙烯醇/中国墨水混合物被均匀涂覆在聚乙烯薄膜上制备了结构稳定的双层软驱动器.由于两层材料的热膨胀系数的显著差异,在氙灯照射下,驱动器能以较快的响应速度实现较大的弯曲变形.通过改变光的强度以及结合尺蠖的仿生结构设计,机器人... 详细信息

聚乙烯醇/中国墨水混合物被均匀涂覆在聚乙烯薄膜上制备了结构稳定的双层软驱动器.由于两层材料的热膨胀系数的显著差异,在氙灯照射下,驱动器能以较快的响应速度实现较大的弯曲变形.通过改变光的强度以及结合尺蠖的仿生结构设计,机器人可以在不同的表面(如纸张和树叶)上实现各种形式的运动.同时在光的驱动下,它可以实现物体的捕获、表情的改变、象鼻的收缩与卷曲以及仿生花朵的开闭等.此外,基于双层驱动器良好的光热转换和灵敏的压力传感性能,它可以实现人体运动监测(如关节弯曲、呼吸、吞咽等),还能与光电转换装置集成.这种多功能、多驱动模式软机器人在可穿戴设备、交通运输、光电转换设备等应用领域具有巨大潜力.

关键词： Chinese ink soft actuator light-driven actuation integration of photoelectric conversion motion monitoring

Manipulating internal flow units toward favorable plasticity in Zr-based bulk-metallic glasses by hydrogenation

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Journal of materials science & Technology 2022年第7期102卷 36-45页

作者： Fuyu Dong Yuexin Chu Mengyuan He Yue Zhang Weidong Li Peter K.Liaw Binbin Wang Liangshun Luo Yanqing Su Robert O.Ritchie Xiaoguang Yuan School of materials science and engineering Shenyang University of TechnologyShenyangChina School of materials science and engineering Northeastern UniversityShenyangChina department of materials science and engineering The University of TennesseeKnoxvilleTNUSA School of materials science and engineering Harbin Institute of TechnologyHarbinChina department of materials science and engineering University of CaliforniaBerkeleyCA94720USA

This work intends to manipulate the internal flow units in Zr_(55)Cu_(30)Ni_(5)Al_(10)bulk-metallic glasses(BMGs)through plasma-assisted hydrogenation to generate a positive microalloying effect on plasticity.Based on the cooperative shear model theory,serration-flow statistics during nanoindentation loading and creep tests during the holding stage were used to analyze the influence of hydrogen on the behavior of flow units in BMGs.Experimental observations showed that the hydrogen in the Zr_(55)Cu_(30)Ni_(5)Al_(10)BMGs caused mechanical softening,plasticity improvement,and structural relaxation.Analysis also showed that the average volume,size,and activation energy of internal flow units in the BMGs all increased as a result of the increase in the hydrogen content.The hydrogenation in the BMGs was found to lead to a prolifera-tion of shear bands,which promoted plasticity.The aggregation of these internal flow units reduced the stress required for plastic deformation through shear bands,ultimately causing softening and structural relaxation.

关键词： Bulk-metallic glass Plasma-assisted hydrogenation Nanoindentation Internal flow unit Serrations Nano-scale creep

Formation of I1 stacking fault by deformation defect evolution from grain boundaries in Mg

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Journal of Magnesium and Alloys 2022年第10期10卷 2717-2729页

作者： Yong-Jie Hu Vaidehi Menon Liang Qi department of materials science and engineering University of MichiganAnn Arbor 48109USA department of materials science and engineering Drexel UniversityPhiladelphia 19104USA

I_(1)stacking faults(SFs)in Mg alloys are regarded as the nucleation sites ofdislocations that are critical for these alloys to achieve high ductility.Previously it was proposed that the formation of I_(1)SFs requires the accumulations of a large number of vacancies,which are difficult to achieve at low temperatures.In this study,molecular dynamics(MD)and molecular statics(MS)simulations based on empirical interatomic potentials were applied to investigate the deformation defect evolutions from the symmetric tilt grain boundaries(GBs)in Mg and Mg-Y alloys under external loading along-axis.The results show the planar faults(PFs)on Pyramidal I planes first appear due to the nucleation and glide of(1/2 c+p)partial dislocations from GBs,where p=1/3(1010).These partial dislocations with pyramidal PFs interact with other defects,including pyramidal PFs themselves,GBs,and ppartial dislocations,generating a large amount of I_(1)SFs.Detailed analyses show the nucleation and growth of I_(1)SFs are achieved by atomic shuffle events and deformation defect reactions without the requirements of vacancy diffusion.Our simulations also suggest the Y clusters at GBs can reduce the critical stress for the formation of pyramidal PFs and I_(1)SFs,which provide a possible reason for the experimental observations that Y promotes thedislocation activities.

关键词： Magnesium alloys I1 stacking faults dislocations Grain boundaries Defect nucleation and evolution Molecular dynamics simulations

Weakly Polarized Organic Cation-Modified Hydrated Vanadium Oxides for High-Energy Efficiency Aqueous Zinc-Ion Batteries

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Nano-Micro Letters 2024年第7期16卷 169-186页

作者： Xiaoxiao Jia Chaofeng Liu Zhi Wang Di Huang Guozhong Cao department of materials science and engineering University of WashingtonSeattleWA 98195USA School of materials science and engineering Tongji UniversityShanghai 201804People’s Republic of China

Vanadium oxides,par-ticularly hydrated forms like V_(2)O_(5)·nH_(2)O(VOH),stand out as promising cathode candidates for aqueous zinc ion batteries due to their adjustable layered structure,unique electronic characteristics,and high theoretical capacities.However,challenges such as vanadium dissolution,sluggish Zn^(2+)diffusion kinetics,and low operating voltage still hinder their direct application.In this study,we present a novel vanadium oxide([C_(6)H_(6)N(CH_(3))_(3)]_(1.08)V_(8)O_(20)·0.06H_(2)O,TMPA-VOH),developed by pre-inserting trimethylphenylammonium(TMPA+)cations into VOH.The incorporation of weakly polarized organic cations capitalizes on both ionic pre-intercalation and molecular pre-intercalation effects,resulting in a phase and morphology transition,an expansion of the interlayer distance,extrusion of weakly bonded interlayer water,and a substantial increase in V^(4+)content.These modifications synergistically reduce the electrostatic interactions between Zn^(2+)and the V-O lattice,enhancing structural stability and reaction kinetics during cycling.As a result,TMPA-VOH achieves an elevated open circuit voltage and operation voltage,exhibits a large specific capacity(451 mAh g^(-1)at 0.1 A g^(-1))coupled with high energy efficiency(89%),the significantly-reduced battery polarization,and outstanding rate capability and cycling stability.The concept introduced in this study holds great promise for the development of high-performance oxide-based energy storage materials.

关键词： Zinc-ion battery Vanadium oxide V_(2)O_(5)·nH_(2)O Pre-intercalation Interlayer engineering

Constructing robust NiFe LDHs-NiFe alloy gradient hybrid bifunctional catalyst for overall water splitting:one-step electrodeposition and surface reconstruction

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Rare Metals 2023年第7期42卷 2272-2283页

作者： Yi-Fei Chen Jia-Hong Li Tian-Tian Liu Si-Hang You Peng Liu Fu-Jin Li Meng-Qi Gao Shu-Guang Chen Fei-Fei Zhang School of materials science and engineering Changsha University of Science and TechnologyChangsha410114China Faculty of engineering Department of Materials Science and EngineeringNational University of SingaporeSingapore117576Singapore School of materials science and engineering Jilin UniversityChangchun130022China

NiFe layered double hydroxides(NiFe LDHs)have been intensively developed for the oxygen evolution reaction(OER)in alkaline media;however,their unsatisfactory hydrogen evolution reaction(HER)performance limits their practical application in overall water splitting.Herein,a simple and efficient one-step electrodeposition method is used to accomplish in situ growth of NiFe LDHsNiFe alloy gradient hybrid coatings on a carbon cloth(CC).Within the binder-free electrode,NiFe LDHs nanosheets with a low-crystalline nature exhibit highly active bifunctional OER/HER activities,and the NiFe alloy acts as a stable electron highway and strong skeleton bridge between NiFe LDHs and the CC.When the electrodes are simultaneously employed as the cathode and anode for overall water splitting,they require low cell potentials of 1.441 V at10 mA·cm^(-2)and 1.703 V at 100 mA·cm^(-2),respectively,and they demonstrate outstanding stability at a current density greater than 100 mA·cm^(-2)for more than 100 h.This is one of the best bifunctional OER and HER catalysts for overall water splitting.Both lattice defects and surface reconstructions crucially contribute to the bifunctional OER/HER activities of NiFe LDHs.This simple and scalable synthesis approach presents an intriguing paradigm for industrial production,and the fabricated electrode has potential application in high-current-density water splitting.

关键词： Bifunctional Electrodeposition Gradient hybrid NiFe layered double hydroxides(NiFe LDHs) Overall water splitting

Surface reconstruction of heterostructures in alkaline medium towards enhanced electrocatalytic hydrogen evolution

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Rare Metals 2024年第6期43卷 2636-2647页

作者： Ming-Yang Yang Ji Yuan Xue-Lian Fu Jing-Jing Chen Jing Hu Zhou-Guang Lu Chen Liu Guangdong Research Center for Interfacial engineering of Functional materials Shenzhen Key Laboratory of Polymer Science and TechnologyShenzhen Key Laboratory of Energy Electrocatalytic MaterialsCollege of Materials Science and EngineeringShenzhen University Shenzhen Key Laboratory of Interfacial science and engineering of materials Department of Materials Science and EngineeringSouthern University of Science and Technology

Constructing heterostructures has proved to be a successful strategy to fabricate electrocatalysts with high efficiency for water splitting.However,the structure evolution in alkaline hydrogen evolution reaction lacks investigation and the specific active center remains disputable.Herein,we take the well-designed Ni3S2@VO2heterostructures as a model to investigate the electrocatalytic activity and the surface reconstruction process of heterostructure catalysts in alkaline electrolyte.The Ni3S2@VO2heterostructures,with Ni3S2nanorods as the core and VO2nanoflakes as the shell,coupled with the high conductive Ni3S2,the hydrophilic VO2and modulated electronic structures at the interfaces,exhibited prominent activity and superior stability at various current densities.Further,the ex-situ characterizations confirmed that the surface reconstruction from Ni3S2@VO2into Ni3S2@amorphous-Ni(OH)2in alkaline media could optimize the water dissociation barrier and exposed large active area,thereby contributing to improved electrocatalytic performance.Our study not only introduces novel high-performance electrocatalysts for hydrogen evolution reaction(HER),but also provides a new avenue for re-examining hetero-structural catalysts in alkaline solutions.

关键词： Heterostructures Ni 3 S 2 @VO 2 Surface reconstruction Water dissociation Alkaline hydrogen evolution

Prediction of grain structure in direct-chill cast Al–Zn–Mg–Cu billets using cellular automaton-finite element method

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Progress in Natural science:materials International 2021年第3期31卷 434-441页

作者： Min-Seok Kim Sang-Hwa Lee Jae-Gil Jung Kwangjun Eah department of materials science and engineering Gachon University Metallic materials Division Korea Institute of Materials Science department of materials science and engineering Yonsei University

A cellular automaton-finite element(CA-FE) model was used to predict the solidification grain structure of permanent mold cast A7086 alloy. In this model, a Gaussian distribution of nucleation sites was adopted, and the Kurz-Giovanola-Trivedi model was extended to a multicomponent Al–Zn–Mg–Cu alloy system to determine the growth kinetics of the dendrite tip. For describing the Gaussian distribution of nucleation sites on the mold surface, an empirical relationship between the initial cooling rate of the melt and the nucleation density was proposed. Under various casting conditions, the calculated grain structures agreed well with the experimental results. Subsequently, the model was applied to the direct-chill(DC) cast billets, and the simulated grain structures reproduced well the experimental results. This confirmed that the current CA-FE model can be used practically and effectively in DC casting processes.

关键词： Cellular automaton-finite element (CA-FE) model Direct-chill casting Al–Zn–Mg–Cu alloy A7068 alloy Grain structure