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Pressure-induced color change arising from transformation between intra-and inter-band transitions in LuH_(2±x)N_(y)

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Science China(Physics,Mechanics & Astronomy) 2024年第2期67卷 161-166页

作者： Zhe liu Yingjie Zhang Shenyang Huang Xue Ming Qing Li Chenghao Pan Yaomin Dai Xiaoxiang Zhou Xiyu Zhu Hugen yan hai-Hu Wen Center for Superconducting Physics and Materials National Laboratory of Solid State Microstructures and Department of PhysicsNational Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China State Key Laboratory of Surface Physics Key Laboratory of Micro and Nano-Photonic Structures of the Ministry of EducationDepartment of PhysicsFudan UniversityShanghai 200433China

The pressure-induced color change in the nitrogen-doped lutetium hydride has triggered extensive discussions about the underlying physics and potential ***,we study the optical response of LuH_(2±x)N_(y)in a broad frequency range at ambient pressure and its evolution with pressure in the visible spectral *** broad-band optical spectra at ambient pressure reveal a Drude component associated with intra-band electronic transitions and two Lorentz components(L1 and L2)arising from inter-band electronic *** application of pressure causes a spectral weight transfer from L1 to the Drude component,leading to a blue shift of the plasma edge in the reflectivity spectrum alongside a reduction of the high-frequency *** results suggest that the pressure-induced color change in LuH_(2±x)N_(y)is closely related to the transformation between intra-and inter-band electronic transitions,providing new insights into the mechanism of the pressure-induced color change in LuH_(2±x)N_(y).

关键词： nitrogen-doped lutetium hydride optical spectroscopy high-pressure technique color change

SMA-origami coupling:online configuration switches and stability property modulation

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International Journal of Smart and Nano Materials 2024年第1期15卷 21-41页

作者： hai Zhou Hongbin Fang Zuolin liu Jian Xu School of Aerospace Engineering and Applied Mechanics Tongji UniversityShanghaiChina Institute of AI and Robotics Fudan UniversityShanghaiChina Yiwu Research Institute Fudan UniversityYiwuZhejiangChina

Active folding is a crucial requirement for practical applications of multi-stable origami ***,research on integrating active materials with origami structures to enable quick configuration switching and modulation of stability properties is still in its early *** advance the state-of-the-art,we designed a coupled structure comprising a stacked Miura-origami(SMO)structure and two Shape Memory Alloy(SMA)*** actuator is used for extruding the SMO structure while the other is used for retracting,thereby realizing bidirectional reversible active folding of the coupled *** the potential energy of the coupled structure shows that it can be switched between monostable and bistable by heating the SMA *** above findings are also confirmed by experiments conducted on a delicate SMO-SMA coupled structure *** activation of different actuators induces rapid configuration switching of the coupled structure,and the stability profile is qualitatively adjusted by designing the current loading profile to achieve steady-state temperature ***,this study provides a new approach to coupling origami structures with smart materials for active folding and presents a novel method to regulate the stability property of origami structures,thus promoting their practical applications.

关键词： Multistability bistable origami active folding smart material

Structural and functional design of geopolymer adsorbents:a review

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Tungsten 2024年第1期6卷 48-76页

作者： hai-Ze Jin Chen-Xi Qiu yan-Song Li Bao liu Jun-Yi liu Qiao Chen Xue-Feng Lu Cui-Xia Li Qi-Kun Wang School of Materials Science and Engineering Lanzhou University of TechnologyLanzhou 730050China State Key Laboratory of Advanced Processing and Recycling of Non-Ferrous Metals Lanzhou 730050China Shenyang Nonferrous Metals Research Institute Co. LTDShenyang 110000China Automotive Engineering Research Institute Jiangsu UniversityZhenjiang 212013China School of Materials Science and Engineering Jingdezhen Ceramic UniversityJingdezhen 333403China

The water pollution derived from the discharge of heavy metals,antibiotics,dyes and surfactants wastewater,*** seriously affected human survival and ecological *** an efficient and low-cost physical wastewater treatment process,the adsorption is a continuous hot spot in related scientific research and *** are non-crystal or semi-crystalline materials with high-efficiency adsorption performance due to the alkali metal ions that balance the electronegative aluminosilicate skeleton can be efficiently replaced by other cations in the aqueous *** related studies of different application conditions,service objects and morphological differences of geopolymer adsorbents based on structure-function design have been in-depth exploration and *** review aims to summarize the research progres s of the structure-function design based on the geopolymerization mechanism and kinetics and service *** overview of service characteristics and progress of geopolymers in the wastewater treatment field(e.g.,dyes,heavy metals,radionuclides,surfactants,antibiotics,ammonium,phosphorus,nitrogen and CO_(2),etc.)are systematically *** the evolution and development of morphological differences and the relationship of structure-function design of geopolymer adsorbents were compared and ***,the challenge worth overcoming,the trends worth considering and perspectives worth developing are highlighted.

关键词： Geopolymer Wastewater Adsorption Structure-function design Application

Characterizing extreme drought and wetness in Guangdong,China using global navigation satellite system and precipitation data

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Satellite Navigation 2024年第1期5卷 258-274页

作者： hai Zhu Kejie Chen haishan Chai Yuanbin Ye Wenjian liu Department of Earth and Space Sciences Southern University of Science and TechnologyShenzhen518055China Lands and Resource Department of Guangdong Province Surveying and Mapping InstituteGuangzhou510500China

As global temperature rises,the frequency of extreme climate events,e.g.,severe droughts and floods,has increased significantly and caused severe damage over the past *** this regard,precipitation efficiency,a crucial meteorological parameter,could provide valuable insights for a better understanding of the patterns and characteristics of these extreme *** this study,taking Guangdong province as an exemplary region,we first obtained long-term and high-resolution historical records of precipitation efficiency by integrating the observations from a dense network of Global Navigation Satellite System(GNSS)stations with precipitation data,and then characterized the extreme drought and wetness through climate *** found a distinct seasonal trend in precipitation efficiency in Guangdong,with annual fluctuations ranging from 10 to 25%.Notably,precipitation efficiency is higher in proximity to the Pearl River Delta Plain and gradually decreases towards the east and *** occurrence of anomalous peaks and valleys in precipitation efficiency generally corresponds to dry and wet conditions,respectively.A total of 9 extreme wet events and 6 dry events occurred from January 2007 to May 2022,with durations from 3 to 6 *** results also demonstrated that both wet and dry frequencies exhibit an increasing trend with the expansion of the time scale,and the frequency of extreme events near the Pearl River Delta Plain surpasses that of other ***,the propagation time from meteorological anomalies to agricultural and hydrological anomalies is about 3 *** periodic characteristics of meteorological anomalies are identified as the primary driver for other anomalous periodic *** work unveils the long-term dynamic behavior of precipitation efficiency,as well as the characteristics of extreme drought and wetness events in the regions characterized by intricate land–atmosphere interactions.

关键词： GNSS Precipitation efficiency Extreme drought and wetness

Progress on the antiferromagnetic topological insulator MnBi2Te4

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National Science Review 2024年第2期11卷 33-49页

作者： Shuai Li Tianyu liu Chang liu Yayu Wang hai-Zhou Lu X.C.Xie Department of Physics Harbin Institute of Technology Shenzhen Institute for Quantum Science and Engineering and Department of Physics Southern University of Science and Technology(SUSTech) Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area(Guangdong) Shenzhen Key Laboratory of Quantum Science and Engineering International Quantum Academy Beijing Academy of Quantum Information Sciences Beijing Key Laboratory of Optoelectronic Functional Materials&Micro-Nano Devices Department of Physics Renmin University of China State Key Laboratory of Low Dimensional Quantum Physics Department of PhysicsTsinghua University Frontier Science Center for Quantum Information Hefei National Laboratory International Center for Quantum Materials School of Physics Peking University Institute for Nanoelectronic Devices and Quantum Computing Fudan University

Topological materials, which feature robust surface and/or edge states, have now been a research focus in condensed maTher physics. They represent a new class of materials exhibiting nontrivial topological phases,and provide a platform for exploring exotic transport phenomena, such as the quantum anomalous Hall effect and the quantum spin Hall effect. Recently, magnetic topological materials have attracted considerable interests due to the possibility to study the interplay between topological and magnetic *** particular, the quantum anomalous Hall and axion insulator phases can be realized in topological insulators with magnetic order. MnBi2Te4, as the first intrinsic antiferromagnetic topological insulator discovered, allows the examination of existing theoretical predictions; it has been extensively studied, and many new discoveries have been made. Here we review the progress made on MnBi2Te4from both experimental and theoretical aspects. The bulk crystal and magnetic structures are surveyed first, followed by a review of theoretical calculations and experimental probes on the band structure and surface states, and a discussion of various exotic phases that can be realized in MnBi2Te4. The properties of MnBi2Te4thin films and the corresponding transport studies are then reviewed, with an emphasis on the edge state transport. Possible future research directions in this field are also discussed.

关键词： MnBi2Te4 magnetic topological insulator antiferromagnetic quantum anomalous Hall effect axion insulator

Solidification/Stabilization of Chromium in Red Mud-based Geopolymer

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Journal of Wuhan University of Technology(Materials Science) 2024年第4期39卷 819-830页

作者：田崇霏 LUO Zhongtao liu Lei liu Xiaohai 张美香陈萌 hai Ran School of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450001China Henan Renbang Technology Co. Ltd.Luoyang 471700China School of Water Conservancy and Civil Engineering Zhengzhou UniversityZhengzhou 450001China School of Architectural and Civil Engineering Zhongyuan University of TechnologyZhengzhou 450007China

Up to 1.5wt%of Cr(Ⅲ)salts(CrCl_(3),and Cr_(2)O_(3))and Cr(Ⅵ)salts(Na_(2)CrO_(4),and CaCr_(2)O_(7))were incorporated into red mud-based geopolymers,*** solidification/stabilization,compressive strength,and durability of the Cr-containing geopolymers were *** experimental results indicate that the red mud-based geopolymer could effectively solidify/stabilize different types of Cr salts with solidification/stabilization rates of above 99.61%.Geopolymers are environmentally safe when the dosage of CaCr_(2)O_(7)is≤1.0wt%,or the dosage of CrCl_(3),Cr_(2)O_(3),and Na_(2)CrO_(4)is≤1.5wt%,*** effects of Cr salts on the compressive strength varies with the type and content of Cr *** freeze-thaw cycle is more destructive to geopolymer properties than sulfate attack or acid rain *** solidification/stabilization of Cr is mainly attributed to the following reasons:a)The chemical binding of Cr is related to the formation of Cr-containing hydrates(eg,magnesiochromite((Mg,Fe)(Cr,Al)_(2)O_(4)))and doping into N-A-S-H gel and C-A-S-H gel framework;b)The physical effect is related to the encapsulation by the hydration products(e g,N-A-S-H gel and C-A-S-H gel).This study provides a reference for the treatment of hazardous Cr-containing wastes by solid waste-based geopolymers.

关键词： chromium solidification/stabilization geopolymer red mud durability

Size effects of boron nitride nanosheets on the growth and silk properties of silkworm

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Size effects of boron nitride nanosheets on the growth and s...

Prediction of surface settlement caused by synchronous grouting during shield tunneling in coarse-grained soils:A combined FEM and machine learning approach

中国蚕学会2021年学术年会

作者： Lin Ma Vivian Andoh hai-yan liu College of Biotechnology Jiangsu University of Science and Technology The Sericultural Research Institute Chinese Academy of Agricultural Sciences Laboratory of Risk Assessment for Sericultural Products and Edible Insects Ministry of Agriculture College of Tea and Food Science Technology Jiangsu Vocational College of Agriculture and Forestry

It is generally known that the biological effects of nanomaterials strongly depend on their *** this study,the boron nitride nanosheets（BN NSs）,a novel material with great potential in biomedical applications,with different sizes are *** kinds of silkworms（qiufeng × baiyu,Nistari 7019） were used as models to investigate the effects of BN NSs with different sizes（BN NSs-1:thickness of 41.5 nm,average diameter of 270.7 nm;BN NSs-2:thickness of 48.2 nm,average diameter of 562.2 nm） on the growth and silk properties of *** results show that exposure to different sized BN NSs causes no obvious adverse effects on the growth or tissues of silkworm,and only BN NSs-1 has some damage to the cocoon of silkworms（cocoon appearance and weight）.XRD,FTIR and SEM results show that the crystalline,secondary or appearance of degummed silks are not *** study has performed size-dependent in vivo biological effects evaluation of BN NSs and provided safety information to enrich the database for better application of BN NSs.

关键词： boron nitride nanosheets silkworm size effect growth silk properties

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Underground Space 2024年第3期16卷 206-223页

作者： Chao liu Zepan Wang hai liu Jie Cui Xiangyun Huang Lixing Ma Shuang Zheng School of Civil Engineering Guangzhou UniversityGuangzhou 510006China Guangdong Engineering Research Center for Underground Infrastructural Protection in Coastal Clay Areas Guangzhou UniversityGuangzhou 510006China Earthquake Engineering Research&Test Center Guangzhou UniversityGuangzhou 510006China CSCEC4 Civil Engineering Co. Ltd.Shenzhen 518052China

This paper presents a surrogate modeling approach for predicting ground surface settlement caused by synchronous grouting during shield tunneling *** proposed method combines finite element simulations with machine learning algorithms and introduces an intelligent optimization algorithm to invert geological parameters and synchronous grouting variables,thereby predicting ground surface settlement without conducting numerous finite element *** surrogate models based on the random forest algorithm are *** first is a parameter inversion surrogate model that combines an artificial fish swarm algorithm with random forest,taking into account the actual number and distribution of complex soil *** second model predicts surface settlement during synchronous grouting by employing actual cover-diameter ratio,inverted soil parameters,and grouting *** avoid changes to input parameters caused by the number of overlying soil layers,the dataset of this model is generated by the finite element model of the homogeneous soil *** surrogate modeling approach is validated by the case history of a large-diameter shield tunnel in Beijing,providing an alternative to numerical computation that can efficiently predict surface settlement with acceptable accuracy.

关键词： Shield tunnel Machine learning Synchronous grouting Surrogate modeling Surface settlement

Strength and ductility optimization of HPDC AlSi8MgCuZn2 alloys by modifying pre-aging treatment

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China Foundry 2024年第4期21卷 343-351页

作者： Yuan-hang Jiang Hui-ting Zheng Fei liu hai-dong Zhao National Engineering Research Center of Near-net Shape Forming for Metallic Materials South China University of TechnologyGuangzhou 510641China

Considering the components produced by high pressure die casting(HPDC)process usually with ultra-large sizes and complex morphologies,high temperature solid solution treatment is not a suitable method to further improve their mechanical *** this study,two-stage aging treatment with different pre-aging times was designed and employed to further improve the mechanical properties of HPDC Al8SiMgCuZn *** characteristics of precipitates were evaluated by a transmission electron microscope(TEM),and the precipitation strengthening mechanism was *** results reveal that the strengthening is mainly contributed by the precipitation ofβ″phase after two-stage aging,and the number density and size of the precipitates are significantly depended on the pre-aging *** number density of precipitates is increased with the pre-aging time prolonged from 0 h to 4 h,and then decreases with the further increase of pre-aging time from 4 h to 6 *** precipitates with the highest density and smallest size are observed after pre-aging for 4 *** pre-aged at 100℃for 4 h and then artificial aged at 200℃for 30 min,the yield strength of 207 MPa,ultimate tensile strength of 325 MPa and elongation of 7.6%are achieved.

关键词： high pressure die cast aluminum alloy microstructural heterogeneity mechanical properties precipitation strengthening two-stage aging