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Dielectric relaxation and conduction behaviors of Aurivillius Na_(0.5)Bi_(4.5)Ti_(4)O_(15) ceramics with Na doping

Rare Metals 2021年第5期40卷 1247-1254页

作者： Fida Rehman Jing-Bo Li Pervaiz Ahmed Muhammad Sheraz Khan Yasir Saeed Asma khan Muhammad Zubair Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications School of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China Department of Physics Abbottabad University of Science&TechnologyHavelian 22500Pakistan Department of Physics University of Azad Jammu and KashmirMuzafarabad 13100Pakistan Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems and School of Physics Beijing Institute of TechnologyBeijing 100081China Department of Chemistry Abbottabad University of Science&TechnologyHavelian 22500Pakistan Key Laboratory of Advanced Functional Materials College of Materials Science and EngineeringMinistry of EducationBeijing University of TechnologyBeijing 100124China

Aurivillius Na_(0.5)Bi_(4.5)Ti_(4)O_(15) and Bi_(4)Ti_(3)O_(12)compounds were synthesized via solid-state reaction technique.X-ray powder diffraction study confirmed monophasic four-layered Na_(0.5)Bi_(4.5)Ti_(4)O_(15) and three-layered Bi_(4)Ti_(3)O_(12) *** relaxation and conduction behaviors of Na-contained Na_(0.5)Bi_(4.5)Ti_(4)O_(15)ceramics were thoroughly investigated in a large scale of temperature of 30-650℃ and frequency of 40 Hz^(-1) *** addition,comparative studies of both the compounds were *** and modulus analyses revealed a single relaxation behavior in Na_(0.5)Bi_(4.5)Ti_(4)O_(15) compound which was originated from the grain’s interior with grain resistance of 2.189×10^(5)Ω and capacitance of 4.268×10^(-10) F at 570℃.While in Bi_(4)Ti_(3)O_(12) ceramic the relaxation was due to the contributions of grain and grain *** current(AC)conductivity analysis revealed the presence of two different conduction regions in both the *** energies for the two different conduction mechanisms,i.e.,in low-temperature region and in high-temperature region were calculated to be~0.23 and~1.27 eV at 1 kHz for Na_(0.5)Bi_(4.5)Ti_(4)O_(15) compound and~0.43 eV and~0.97 eV at 1 kHz for Bi_(4)Ti_(3)O_(12) compound,*** present study of dielectric relaxation and conduction behaviors would be helpful for further investigations of Na_(0.5)Bi_(4.5)Ti_(4)O_(15)-related Aurivillius compounds.

关键词： Na_(0.5)Bi_(4.5)Ti_(4)O_(15) Electronic ceramics Dielectric Impedance Electrical properties

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From Models to Devices: Smart Thermal Storage/ Release Walls for Green Buildings

SSRN

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SSRN 2024年

作者： Wang, Han Zhang, Xun Wang, Ruzhi Institute of Advanced Energy Materials and Devices College of Material Science and Engineering Key Laboratory of Advanced Functional Materials of Education Ministry of China Beijing University of Technology Beijing100124 China

The efficient energy-saving, energy storage, and energy release of buildings have always been of interest to people and is also very important for carbon emissions. To design low-carbon or zero-carbon buildings, some traditional and complex methods are often adopted, which includes static or dynamic energy analysis methods. However, these complicated methods generally require a significant computational burden, which are also difficult to directly establish a quantitative relationship between energy consumption (EC) and carbon emissions (CE) from the structural properties of the buildings. In this work, we present a general model for computing the EC and CE of building with very low computational complexity and effort. Furthermore, from the general model, we designed smart green building walls(SGBW), which can serve as the thermal storage/release carrier by the inner and outer films(TSF&TRF) of buildings. The SGBW absorbs solar energy for storage during high temperatures and unidirectionally releases heat indoors during low temperatures. Simulation results indicate that with the addition of TSF and TRF, the SGBW has 18.7% higher heat storage capacity and 30.4% higher heat release capacity compared to cement walls. In addition, our modeling calculations show that each square meter of SGBW can save 417~805 kWh of electricity and reduces CO2 emissions by 225~477 kg for buildings in different climatic zones throughout its lifecycle, which is well agreed with the complicated methods used in the big commercial software. Therefore, the general model simplifies complex simulation processes and guides the design of surface devices. The SGBW is expected to be applied in buildings located in areas with nighttime heating needs, providing significant assistance in regulating indoor temperatures while reducing building EC and CE. © 2024, The Authors. All rights reserved.

关键词： Solar energy

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Partially Solvated Cosolvent Induced Reconfiguration of Solvation Structure and Helmholtz Layer for Lithium Metal Battery

SSRN

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SSRN 2024年

作者： Huang, Minghao Wang, Yueda Liu, Yongchao Zhou, Rulong Hou, Qian Xiang, Hongfa School of Materials Science and Engineering Anhui Provincial Key Laboratory of Advanced Functional Materials and Devices Hefei University of Technology Anhui Hefei230009 China

Reconfiguring the electrolyte microstructure containing Li+ solvation structure in bulk electrolyte and Helmholtz layer (HL) near the interface presents a compelling strategy in the design of electrolytes. In this work, ionic liquids (ILs) and partially solvated fluorobenzene (FB) build the unique Li+ coordination state modulated by FB and dominated by anions as well as a HL enriched in non-sacrificial cations on charging. As an important part to regulate the micro environment, FB not only enhances the ion transport kinetics of electrolyte and promotes the interaction of Li+-FSI-,but also participate in constructing a robust solid electrolyte interphase (SEI). Interestingly, FB indirectly promotes the enrichment of ILs’ cations at the HL, which is beneficial for uniform Li metal deposition due to its electrostatic shielding effect. Li metal batteries utilizing this electrolyte demonstrate impressive cycling performance at a high rate (approximately 89% capacity retention after 2,500 cycles at 5C). Furthermore, these cells show excellent high-temperature performance, maintaining 71% of the initial capacity after 1,000 cycles at 70 °C and 10C rate. © 2024, The Authors. All rights reserved.

关键词： Solvation

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

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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 *** 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 *** 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 *** 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 ***,the nanoscale Al 2 Cu formed by the reaction of Cu-NPs and Al matrix played a role in precipitation ***,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

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Laser patterning of large-scale perovskite single-crystal-based arrays for single-mode laser displays

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International Journal of Extreme Manufacturing 2023年第4期5卷 462-470页

作者： Wangqi Mao Haonan Li Bing Tang Chi Zhang Liang Liu Pei Wang Hongxing Dong Long Zhang Department of Optics and Optical Engineering University of Science and Technology of ChinaHefeiAnhui 230026People’s Republic of China Key Laboratory of Materials for High-Power Laser Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800People’s Republic of China Department of Materials Science and Engineering and Centre for Functional Photonics(CFP)City University of Hong KongHong Kong Special Administrative Region of China 999077People’s Republic of China School of Physics and Optoelectronic Engineering Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhouZhejiang 310024People’s Republic of China Key Laboratory for Micro/Nano Physics and Technology of Hunan Province State Key Laboratory of Chemo/Biosensing and ChemometricsCollege of Materials Science and EngineeringHunan UniversityChangsha 410082People’s Republic of China

Lead halide perovskites have attracted considerable attention as potential candidates for high-performance nano/microlasers,owing to their outstanding optical ***,the further development of perovskite microlaser arrays(especially based on polycrystalline thin films)produced by the conventional processing techniques is hindered by the chemical instability and surface roughness of the perovskite ***,we demonstrate a laser patterning of large-scale,highly crystalline perovskite single-crystal films to fabricate reproducible perovskite single-crystal-based microlaser *** thin films were directly ablated by femtosecond-laser in multiple low-power cycles at a minimum machining line width of approximately 300 nm to realize high-precision,chemically clean,and repeatable fabrication of microdisk *** surface impurities generated during the process can be washed away to avoid external optical loss due to the robustness of the single-crystal ***,the high-quality,large-sized perovskite single-crystal films can significantly improve the quality of microcavities,thereby realizing a perovskite microdisk laser with narrow linewidth(0.09 nm)and low threshold(5.1µJ/cm2).Benefiting from the novel laser patterning method and the large-sized perovskite single-crystal films,a high power and high color purity laser display with single-mode microlasers as pixels was successfully ***,this study may offer a potential platform for mass-scale and reproducible fabrication of microlaser arrays,and further facilitate the development of highly integrated applications based on perovskite materials.

关键词： perovskite single-crystal film single-mode microlaser femtosecond-laser processing laser display Supplementary material for this article is available online

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Simultaneous diffusion of cation and anion to access N,S cocoordinated Bi-sites for enhanced CO_(2) electroreduction

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Nano Research 2021年第8期14卷 2790-2796页

作者： Zhiyuan Wang Chun Wang Yidong Hu Shuai Yang Jia Yang Wenxing Chen Huang Zhou Fangyao Zhou Lingxiao Wang Junyi Du Yafei Li Yuen Wu School of Chemistry and Materials Science Hefei National Laboratory for Physical Sciences at the MicroscaleUniversity of Science and Technology of ChinaHefei 230026China Jiangsu Collaborative Innovation Centre of Biomedical Functional Materials Jiangsu Key Laboratory of New Power BatteriesSchool of Chemistry and Materials ScienceNanjing Normal UniversityNanjing 210023China Dalian National Laboratory for Clean Energy Dalian 116023China Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201210China Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China Institutes of Physical Science and Information Technology Key Laboratory of Structure and Functional Regulation of Hybrid MaterialsMinistry of EducationAnhui Graphene Engineering LaboratoryAnhui UniversityHefei 230601China

Developing highly active single-atom sites catalysts for electrochemical reduction of CO_(2) is an effective and environmental-friendly strategy to promote carbon-neutral energy cycle and ameliorate global climate ***,we develop an atomically dispersed N,S co-coordinated bismuth atom sites catalyst(Bi-SAs-NS/C)via a cation and anion simultaneous diffusion strategy for electrocatalytic CO_(2) *** this strategy,the bonded Bi cation and S anion are simultaneously diffused into the nitrogen-doped carbon layer in the form of *** Bi is captured by the abundant N-rich vacancies and S is bonded with *** at high temperature,formed the N,S co-coordinated Bi *** from the simultaneous diffusion of Bi and S,different electronegative N and S can be effectively co-coordinated with Bi,forming the uniform Bi-N_(3)S/C *** ***-SAs-NS/C exhibits a high selectivity towards CO with over 88%Faradaic efficiency in a wide potential range,and achieves a maximum FE_(CO)of 98.3%at-0.8 V *** with a current density of 10.24 mA·cm^(-2),which can keep constant with negligible degradation in 24 h continuous *** results and theoretical calculations reveal that the significantly improved catalytic performance of Bi-SAs-NS/C than Bi-SAs-N/C is ascribed to the replacement of one coordinated-N with low electronegative S in Bi-N_(4)C center,which can greatly reduce the energy barrier of the intermediate formation in rate-limiting step and increase the reaction *** work provides an effective strategy for rationally designing highly active single-atom sites;catalysts for efficient electrocatalysis with optimized electronic structure.

关键词： S,N-co-doped carbon nanotube single bismuth sites electronic structure modulation electrochemical CO_(2)reduction

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Electronic and topological properties of kagome lattice LaV3Si2

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Tungsten 2023年第3期5卷 317-324页

作者： Xue-Jiao Chen Bing-Wen Zhang Dong Han Zhi-Cheng Zhong CAS Key Laboratory of Magnetic Materials Devices and Zhejiang Province Key Laboratory of Magnetic Materials and Application TechnologyNingbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo 315201China Fujian Key Laboratory of Functional Marine Sensing Materials Center for Advanced Marine Materials and Smart SensorsCollege of Material and Chemical EngineeringMinjiang UniversityFuzhou 350108China Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of SciencesChangchun 130033China China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

Topological kagome lattice at the frontier of fundamental physics plays a key role in non-trivial topological quantum ***,we predict and investigate kagome lattice rare-earth vanadium-based quantum material LaV3Si2using density functional theory *** phonon spectrum and crystal transformation show stability of this material,which may be grown by experimental *** fermions,flat bands,and van Hove points as some basic features are presented in band structure and surface ***,symmetry-based compatibility relations support enforced semi-metal for occupied electron numbers with strong Berry *** results suggest that rare-earth vanadium-based RV3Si2can be treated as a new family kagome lattice.

关键词： Vanadium Kagome lattice Rare earth Electronic Dirac points

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Preparation of high performance Ga2O3 based ultraviolet photodetector by CVD

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Journal of Solid State Chemistry 2023年第PartA期317卷

作者： Wang, Xiao Cheng, Qiao Rong, Ximing Han, Shun Zeng, Yuxiang Cao, Peijiang Fang, Ming Liu, Wenjun Zhu, Deliang Lu, Youming Shenzhen Key Laboratory of Special Functional Materials Shenzhen Engineering Laboratory for Advanced Technology of Ceramics Guangdong Research Center for Interfacial Engineering of Functional Materials College of Materials Science and Engineering Shenzhen University Shenzhen518055 China

Here, β-Ga2O3 films have been grown on c-Al2O3 and p-GaN substrates by chemical vapor deposition method to fabricate solar-blind ultraviolet photodetectors with MSM-type planar structure and pn-junction vertical structure respectively. The β-Ga2O3 films grown with domain growth mode exhibit high crystallinity and flat surface, so the fabricated MSM-type photodetector shows spectral peak responsivity of 1.83 A/W at 254 nm and photo-to-dark current ratio of 104 under 25 V bias with 20% oxygen fraction and 120 sccm flow rate. On this basis, the constructed vertical structured β-Ga2O3/p-GaN heterojunction photodetector shows peak responsivity of 1.99 A/W under 25 V for the junction effect between β-Ga2O3 and p-GaN. Meanwhile, spectral responsivity peak of 1.36 × 10−4 A/W at 0V claims significant self-powered effect induced by build-in electric field between β-Ga2O3 and p-GaN. These results confirm that high performance β-Ga2O3 solar-blind ultraviolet photodetectors can be obtained by simple chemical vapor deposition method. © 2022 Elsevier Inc.

关键词： Heterojunctions

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A Deep Learning Framework Based on Attention Mechanism for Predicting The Mechanical Properties and Failure Pattern of Embedded Wrinkle Fiber-Reinforced composites

SSRN

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SSRN 2023年

作者： Liu, Chen Li, Xuefeng Ge, Jingran Liu, XiaoDong Li, BingYao Liu, ZengFei Liang, Jun Institute of Advanced Structure Technology Beijing Institute of Technology Beijing100081 China Beijing Key Laboratory of Lightweight Multi-functional Composite Materials and Structures Beijing Institute of Technology Beijing100081 China State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology Beijing100081 China

To avoid the expensive computational costs and time-consuming process of high-fidelity simulation, a deep learning framework based on attention mechanism and three-dimensional stress state is proposed to predict the compressive mechanical properties and failure modes of embedded wrinkle thick-section composites in this paper. The deep learning framework includes strength and stiffness, stress-strain curves and failure mode prediction networks respectively using convolutional neural networks (CNN) based on wrinkle angle distribution and material distribution. The attention-based loss function is considered in the failure mode network to accurately predict the local high damage areas. 1025 finite element (FE) models considering the geometric features of the embedded wrinkles are generated based on the Latin Hypercube sampling technique. The high-fidelity three-dimensional FE simulations based progressive damage method are used to compute the datasets for training and validating the deep learning framework. The results show that the deep learning framework can accurately predict the compressive mechanical properties and failure modes of embedded wrinkle composites. Meanwhile, the deep learning framework also captures the influence laws of wrinkle parameters on mechanical properties and failure modes. © 2023, The Authors. All rights reserved.

关键词： Forecasting

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Optimizing geometric configuration of single Zn-N_(4) sites for boosting reciprocal transformation between aromatic alcohols and aldehydes

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Nano Research 2023年第7期16卷 9132-9141页

作者： Shengjie Wei Yucheng Jin Chunlin Lv Chao Lian Zheng Chen Xiao Liang Qinghua Zhang Xin Chen Dongdong Qi Zhi Li School of Materials Science and Engineering Nankai UniversityTianjin 300350China Department of Chemistry Tsinghua UniversityBeijing 100084China Beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline Materials Department of ChemistryUniversity of Science and Technology BeijingBeijing 100083China School of Pharmacy and Center on Translational Neuroscience Minzu University of ChinaBeijing 100081China Department of Chemistry School of ScienceBeijing Jiaotong UniversityBeijing 100091China School of Chemistry and Materials Science Anhui Normal UniversityWuhu 241002China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China Beijing Advanced Innovation Center for Materials Genome Engineering Institute of Solid State ChemistryUniversity of Science and Technology BeijingBeijing 100083China College of Chemistry Beijing Normal UniversityBeijing 100875China

It is significant to optimize geometric configuration of metal catalytic sites and boost their catalytic ***,we synthesized isolated single Zn-N_(4)sites on N-doped carbon(Zn-CN)by pyrolyzing zeolite imidazole framework-8(ZIF-8)at different *** the reciprocal transformation between benzyl alcohol and benzaldehyde,the catalytic activities of Zn-CN catalysts exhibited a volcano-like trend as the pyrolysis temperatures *** optimal catalyst was Zn-CN-900,with outstanding catalytic activity exceeding commercial 20 wt.%Pd/C and 20 wt.%Pt/C,promising to substitute the noble metalbased catalysts.X-ray absorption near-edge structure(XANES)measurements and density functional theory(DFT)calculation revealed the gradual transformation from tetrahedral ZnN_(4)sites of ZIF-8 into planar ZnN_(4)sites above 700℃,with the maximum planar ZnN_(4)sites in *** stronger adsorption between reactants and planar ZnN_(4)sites facilitated the activation of reactants compared with tetrahedral ZnN_(4)*** work will provide valuable insight into rational design of efficient catalysts by optimizing geometric configuration of catalytic sites.

关键词： geometric configuration single Zn-N_(4)sites benzyl alcohol oxidation hydrogen transfer reaction

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