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Defects evolution in n-type 4H-SiC induced by electron irradiation and annealing

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Journal of Semiconductors 2024年第7期45卷 77-83页

作者： Huifan Xiong xuesong lu xu Gao Yuchao Yan Shuai Liu Lihui Song Deren yang Xiaodong Pi State Key Laboratory of Silicon and Advanced Semiconductor Materials&School of Materials Science and Engineering Zhejiang UniversityHangzhou 310027China Key Laboratory of Power Semiconductor Materials and Devices of Zhejiang Province&Institute of Advanced Semiconductors ZJU-Hangzhou Global Scientific and Technological Innovation CenterZhejiang UniversityHangzhou 311200China

Radiation damage produced in 4H-SiC by electrons of different doses is presented by using multiple characterization techniques. Raman spectra results indicate that SiC crystal structures are essentially impervious to 10 Me V electron irradiation with doses up to 3000 kGy. However, irradiation indeed leads to the generation of various defects, which are evaluated through photoluminescence(PL) and deep level transient spectroscopy(DLTS). The PL spectra feature a prominent broad band centered at 500 nm, accompanied by several smaller peaks ranging from 660 to 808 nm. The intensity of each PL peak demonstrates a linear correlation with the irradiation dose, indicating a proportional increase in defect concentration during irradiation. The DLTS spectra reveal several thermally unstable and stable defects that exhibit similarities at low irradiation ***, after irradiating at the higher dose of 1000 kGy, a new stable defect labeled as R_(2)(Ec-0.51 eV) appeared after annealing at 800 K. Furthermore, the impact of irradiation-induced defects on SiC junction barrier Schottky diodes is discussed. It is observed that high-dose electron irradiation converts SiC n-epilayers to semi-insulating layers. However, subjecting the samples to a temperature of only 800 K results in a significant reduction in resistance due to the annealing out of unstable defects.

关键词： 4H-SiC deep level transient spectroscopy(DLTS) photoluminescence(PL) defects

An improved analysis method for assessing the nuclear-heating impact on the stability of toroidal field magnets in fusion reactors

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Nuclear Science and Techniques 2024年第6期35卷 163-176页

作者： Yu-Dong lu Jin-Xing Zheng xu-Feng Liu Huan Wu Jian Ge Kun xu Ming Li Hai-yang Liu Lei Zhu Fei Liu Institute of Plasma Physics Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China University of Science and Technology of China Hefei 230026China

The superconducting magnet system of a fusion reactor plays a vital role in plasma confinement,a process that can be dis-rupted by various operational factors.A critical parameter for evaluating the temperature margin of superconducting magnets during normal operation is the nuclear heating caused by D-T *** study investigates the impact of nuclear heat-ing on a superconducting magnet system by employing an improved analysis method that combines neutronics and thermal *** the magnet system,toroidal field(TF)magnets are positioned closest to the plasma and bear the highest nuclear-heat load,making them prime candidates for evaluating the influence of nuclear heating on *** enhance the modeling accuracy and facilitate design modifications,a parametric TF model that incorporates heterogeneity is established to expedite the optimization design process and enhance the accuracy of the computations.A comparative analysis with a homogeneous TF model reveals that the heterogeneous model improves accuracy by over 12%.Considering factors such as heat load,magnetic-field strength,and cooling conditions,the cooling circuit facing the most severe conditions is selected to calculate the temperature of the *** selection streamlines the workload associated with thermal-hydraulic *** approach enables a more efficient and precise evaluation of the temperature margin of TF ***,it offers insights that can guide the optimization of both the structure and cooling strategy of superconducting magnet systems.

关键词： Superconducting magnet Nuclear heating Neutronics Thermal hydraulics

pH- and near-infrared light-responsive,biomimetic hydrogels from aqueous dispersions of carbon nanotubes

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Nano Research 2024年第4期17卷 3120-3129页

作者： lulin Hu Xinxin Yu Jingcheng Hao lu xu Shandong Laboratory of Yantai Advanced Materials and Green Manufacturing Yantai 264000China State Key Laboratory of Solid lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China Yantai Center for Food and Drug Control Yantai 264000China Key Laboratory of Colloid and Interface Chemistry&Key Laboratory of Special Aggregated Materials Shandong UniversityJinan 250100China

Owing to their low flexibility,poor processability and a lack of responsiveness,inorganic materials are usually non-ideal for constructing a living ***,to date,lifelike materials with structural hierarchies and adaptive properties usually rely on light and soft organic molecules,although few exceptions have been acquired using two-dimensional(2D)inorganic ***,with a systematic study on the gelation behavior of carbon-based 0D quantum dots,1D nanotubes,and 3D fullerenes,we find that acidified 1D carbon nanotubes(CNTs)can serve as an alternative building block for fabricating purely inorganic biomimetic soft *** as-prepared CNT gels exhibit not only a pH-or photothermal-triggered mechanical and tribological adaptivity,which allows them to simulate the behavior of sea cucumbers,peacock mantis shrimps,and mammalian muscles or cortical bones,but also a unique damping property that is similar to spider’s cuticular *** high elasticity,effective lubrication,excellent biocompatibility,and controllable friction and wear also allow them to function as a new type of smart lubricants,whose tribological properties can be regulated either by its internal pH changes or spatiotemporally by near-infrared(NIR)light irradiations,free of any toxic and flammable base oils or additives.

关键词： biomimetic hydrogels carbon nanotubes(CNTs) mechanical and tribological adaptivity pH-and near-infrared(NIR)light responsiveness switchable lubrication

Flower-like CuS/γ-Fe_(2)O_(3) van der Waals heterostructures with highefficient electromagnetic wave absorption

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Nano Research 2024年第4期17卷 3324-3333页

作者： Na lu Jingshen xu Mengwei Yuan Genban Sun Beijing Key Laboratory of Energy Conversion and Storage Materials Institution College of ChemistryBeijing Normal UniversityBeijing 100875China Center for Advanced Materials Research Beijing Normal UniversityZhuhai 519087China

The escalating electromagnetic(EM)pollution issues and the demand to elevate military stealth technology make it imperative to develop cost-effective and high-performance electromagnetic wave(EMW)absorbing *** this paper,the flower-like CuS/γ-Fe_(2)O_(3) van der Waals(vdW)heterostructures have been synthesized via a facile two-step solvothermal *** flower-like CuS skeleton increases the attenuation path of EMW while reducing the material *** contents ofγ-Fe_(2)O_(3) nanoparticles anchor between the flower-like CuS nanosheets to constitute a heterogeneous structure,which enables dielectric and magnetic loss synergistically to optimize impedance matching and remarkably improve the EMW absorption *** minimum reflection loss(RLmin)is-49.36 dB with a thickness of only 1.6 mm and the effective absorption bandwidth(EAB)reaches 4.64 GHz(13.36–18 GHz).By adjusting the thickness of the absorber,the EAB can cover 96%of the GHz ***,the superior absorption of-61.53 dB at middle frequency band can be obtained by adjusting the amount of Fe_(2)O_(3) *** this study,the adjustment of EM parameters and the optimization of impedance matching have been achieved by constructing a novel vdW heterogeneous structure,which provides fresh ideas and references for the design of high-performance EMW absorbing materials.

关键词： flower-like CuS γ-Fe_(2)O_(3) van der Waals heterostructures impedance matching electromagnetic wave absorption

Hierarchical crystalline-amorphous nanocomposites with high strength and large deformability enabled by elemental diffusion

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Journal of Materials Science & Technology 2024年第4期171卷 150-161页

作者： Liqiang Wang Heyi Wang Xin Zhou Huangliu Fu James Utama Surjadi Shuo Qu xu Song Rong Fan yang lu Department of Mechanical Engineering City University of Hong KongHong KongChina Nano-Manufacturing Laboratory(NML) Shenzhen Research Institute of City University of Hong KongShenzhen 518057China Chengdu Research Institute City University of Hong KongChengdu 610200China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Department of Mechanical and Automation Engineering The Chinese University of Hong KongHong KongChina Department of Mechanical Engineering The University of Hong KongHong KongChina

Amorphous/nanocrystalline dual-phase structures have recently emerged as an effective way for over-coming the strength-ductility trade-offand breaking the limitation of the reverse Hall-Petch ***,we proposed a new strategy to develop a hierarchical and interconnected amorphous-crystalline nanocomposite arising from the nanoscale elemental interdiffusion and oxygen adsorption behavior dur-ing thermal treatment *** nanocomposite consisted of a three-dimensional(3D)hierarchical network structure where the crystalline phase(Cr-Co-Ni-Al)was embedded into the Al-O-based amor-phous phase network with critical feature sizes encompassing three orders of magnitude(from microm-eter to nanometer scale).It can achieve ultrahigh compression yield strength of-3.6 GPa with large homogeneous deformation of over 50%*** massive interstitial atoms induced lattice distortion and hierarchical amorphous phase boundary contributed to the strength *** situ Uniaxial compression inside a transmission electron microscope(TEM)revealed that the exceptional deformability of the nanocomposites resulted from the homogenous plastic flow of nano-sized amorphous phase and the plastic co-deformation behavior restricted by the nano-architected dual-phase *** proposed dual-phase synthesis approach can outperform conventional nanolaminates design strategies in terms of the mechanical properties achievable while providing a pathway to easily tune the microstructure of these nanolaminates.

关键词： Nanolaminates Dual-phase nanocomposites In situ transmission electron microscopy Multi-component alloy

The manipulation of rectifying contact of Co and nitrogen-doped carbon hierarchical superstructures toward high-performance oxygen reduction reaction

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Carbon Energy 2024年第9期6卷 338-349页

作者： Jing Li Tingyu lu Yu Fang Guangyao Zhou Mingyi Zhang Huan Pang Jun yang Yawen Tang Lin xu Jiangsu Key Laboratory of New Power Batteries School of Chemistry and Materials ScienceJiangsu Collaborative Innovation Center of Biomedical Functional MaterialsNanjing Normal UniversityNanjingJiangsuChina College of Science Jinling Institute of TechnologyNanjingJiangsuChina Key Laboratory for Photonic and Electronic Bandgap Materials Ministry of EducationSchool of Physics and Electronic EngineeringHarbin Normal UniversityHarbinHeilongjiangChina School of Chemistry and Chemical Engineering Yangzhou UniversityYangzhouJiangsuChina State Key Laboratory of Multiphase Complex Systems Center of MesoscienceInstitute of Process EngineeringChinese Academy of SciencesBeijingChina

Rational design and construction of oxygen reduction reaction(ORR)electrocatalysts with high activity,good stability,and low price are essential for the practical applications of renewable energy conversion devices,such as metal-air *** modification through constructing metal/semiconductor Schottky heterointerface represents a powerful strategy to enhance the electrochemical ***,we demonstrate a concept of Schottky electrocatalyst composed of uniform Co nanoparticles in situ anchored on the carbon nanotubes aligned on the carbon nanosheets(denoted as Co@N-CNTs/NSs hereafter)toward *** experimental findings and theoretical simulation testify that the rectifying contact could impel the voluntary electron flow from Co to N-CNTs/NSs and create an internal electric field,thereby boosting the electron transfer rate and improving the intrinsic *** a consequence,the Co@N-CNTs/NSs deliver outstanding ORR activity,impressive long-term durability,excellent methanol tolerance,and good performance as the air-cathode in the Zn-air *** design concept of Schottky contact may provide the innovational inspirations for the synthesis of advanced catalysts in sustainable energy conversion fields.

关键词： Co-based electrocatalysts oxygen reduction reaction rectifying contact Zn-air batteries

Evolution of the porous structure for phosphoric acid etching carbon as cathodes in Li–O_(2) batteries:Pyrolysis temperature-induced characteristics changes

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Carbon Energy 2024年第1期6卷 172-181页

作者： Feiyang yang Ying Yao Yunkai xu Cong Wang Meiling Wang Jingjie Ren Cunzhong Zhang Feng Wu Jun lu Beijing Key Laboratory of Environmental Science and Engineering School of Materials Science and EngineeringBeijing Institute of TechnologyBeijingChina Beijing Institute of Technology Chongqing Innovation Center ChongqingChina College of Chemical and Biological Engineering Zhejiang UniversityHangzhouChina

Although biomass-derived carbon(biochar)has been widely used in the energy field,the relation between the carbonization condition and the physical/chemical property of the product remains ***,we revealed the carbonization condition's effect on the morphology,surface property,and electrochemical performance of the obtained *** open slit pore structure with shower-puff-like nanoparticles can be obtained by finely tuning the carbonization temperature,and its unique pore structure and surface properties enable the Li–O_(2) battery with cycling longevity(221 cycles with 99.8%Coulombic efficiency at 0.2 mA cm^(−2) and controlled discharge–charge depths of 500 mAh g^(−1))and high capacity(16,334 mAh g^(−1) at 0.02 mA cm^(−2)).This work provides a greater understanding of the mechanism of the biochar carbonization procedure under various pyrolysis conditions,paving the way for future study of energy storage devices.

关键词： biomass Li-O_(2) battery oxygen catalysts porous carbon temperature parameters

Performance-control-orientated hybrid metal additive manufacturing technologies:state of the art,challenges,and future trends

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International Journal of Extreme Manufacturing 2024年第3期6卷 274-328页

作者： Jiming Lv Yuchen Liang Xiang xu Gang xu Hongmei Zhang Haifei lu Kaiyu luo Jie Cai Jinzhong lu School of Mechanical Engineering Jiangsu UniversityZhenjiang 212013People’s Republic of China School of Mechanical Engineering Jiangsu University of Science and TechnologyZhenjiang 212003People’s Republic of China

Metal additive manufacturing(AM)technologies have made significant progress in the basic theoretical field since their invention in the ***,performance instability during continuous processing,such as thermal history,residual stress accumulation,and columnar grain epitaxial growth,consistently hinders their broad application in standardized industrial *** overcome these challenges,performance-control-oriented hybrid AM(HAM)technologies have been *** technologies,by leveraging external auxiliary processes,aim to regulate microstructural evolution and mechanical properties during metal *** paper provides a systematic and detailed review of performance-control-oriented HAM technology,which is categorized into two main groups:energy field-assisted AM(EFed AM,***,electromagnetic,and heat)technologies and interlayer plastic deformation-assisted AM(IPDed AM,*** shock peening,rolling,ultrasonic peening,and friction stir process)*** review covers the influence of external energy fields on the melting,flow,and solidification behavior of materials,and the regulatory effects of interlayer plastic deformation on grain refinement,nucleation,and ***,the role of performance-control-oriented HAM technologies in managing residual stress conversion,metallurgical defect closure,mechanical property improvement,and anisotropy regulation is thoroughly reviewed and *** review concludes with an analysis of future development trends in EFed AM and IPDed AM technologies.

关键词： hybrid additive manufacturing in-situ/interlayer plastic deformation auxiliary energy fields microstructure customization mechanical properties enhancement

A neuromorphic device mimicking synaptic plasticity under different body fluid K^(+) homeostasis for artificial reflex path construction and pattern recognition

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Fundamental Research 2024年第2期4卷 353-361页

作者： lu yang Yao Ni Chengpeng Jiang lu Liu Song Zhang Jiaqi Liu Lin Sun Wentao xu Institute of Photoelectronic Thin Film Devices and Technology Key Laboratory of Optoelectronic Thin Film Devices and Technology of TianjinEngineering Research Center of Thin Film Photoelectronic TechnologyMinistry of EducationNankai UniversityTianjin 300350China Shenzhen Research Institute of Nankai University Shenzhen 518000China

The ionic environment of body fluids influences nervous functions for maintaining homeostasis in organisms and ensures normal perceptual abilities and reflex *** reflex activities,such as limb movements,are closely associated with potassium ions(K+).In this study,we developed artificial synaptic devices based on ion concentration-adjustable gels for emulating various synaptic plasticities under different K+concentrations in body *** addition to performing essential synaptic functions,potential applications in information processing and associative learning using short-and long-term plasticity realized using ion concentration-adjustable gels are *** synaptic devices can be used for constructing an artificial neural pathway that controls artificial muscle reflex activities and can be used for image pattern *** tests show a strong relationship with ion *** devices could be applied to neuromorphic robots and human-machine interfaces.

关键词： Nervous regulation Artificial synaptic device Ion gel Ion homeostasis Artificial reflex pathway