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Curvature geometry in 2D materials

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National Science Review 2023年第8期10卷 232-242页

作者： Nan Wei Yiran ding Jiaqian Zhang Linyi Li Mengqi Zeng Lei fu College of Chemistry and Molecular Sciences Wuhan University The Institute for Advanced Studies Wuhan University

The two-dimensional(2D) material family can be regarded as the extreme externalization form of the matter in the planar 2D space. These atomically thin materials have abundant curvature structures, which will significantly affect their atomic configurations and physicochemical properties. Curvature engineering offers a new tuning freedom beyond the thoroughly studied layer number, grain boundaries, stacking order,etc. The precise control of the curvature geometry in 2D materials can redefine this material family. Special attention will be given to this emerging field and highlight possible future directions. With the step-by-step achievement in understanding the curvature engineering effect in 2D materials and establishing reliable delicate curvature controlling strategies, a brand-new era of 2D materials research could be developed.

关键词： 2D materials curvature geometry deformation strain

Domain Adaptive Learning with Multi-Granularity Features for Unsupervised Person Re-identification

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Chinese Journal of Electronics 2022年第1期31卷 116-128页

作者： fu Lihua DU Yubin ding Yu WANG Dan JIANG Hanxu ZHANG Haitao Beijing University of Technology

Unsupervised person re-identification(Re-ID) aims to improve the model's scalability and obtain better Re-ID results in the unlabeled data domain. In this paper, we propose an unsupervised person Re-ID method based on multi-granularity feature representation and domain adaptive learning, which can effectively improve the performance of unsupervised person re-identification. The multi-granularity feature extraction module integrates global and local information of different granularity to obtain the multi-granularity person feature representation with rich discriminative information. The source domain classification module learns the labeled source dataset classification and obtains the person's discriminative knowledge in the source domain. On this basis, the domain adaptive module further considers the difference between the target domain and the source domain to learn adaptively for the model. Experiments on multiple public datasets show that the proposed method can achieve a competitive performance among other stateof-the-art unsupervised Re-ID methods.

关键词： feature extraction unsupervised person re-identification image classification multigranularity feature extraction module multigranularity person feature representation deep learning (artificial intelligence) deep learning domain adaptive learning source domain classification module unsupervised person Re-ID domain adaptive module

Step it up: Advancing physical activity research to promote healthy aging in China

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Journal of Sport and Health Science 2016年第3期5卷 255-257,382页

作者： ding ding Hua fu Adrian E.Bauman Prevention Research Collaboration Sydney School of Public Health The University of Sydney Centre for Chronic Disease Prevention College of Public Health Medical and Veterinary Sciences James Cook University School of Public Health Fudan University

*** China has been *** the late 1970s,China’s economy has increased many fold,the proportion of Chinese living in urban areas has more than doubled,life expectancy has increased by 10 years^1 and the country has transitioned from the'bicycle kingdom'to the world’s largest'auto market'.~2 As a result,China is now challenged by the'side effects'of eco-

关键词： doubled proportion lifestyle expenditure programs pragmatic innovative faster encourage accumulating

The shapes of synthesized two‐dimensional materials

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SmartMat 2023年第3期4卷 9-32页

作者： Xiao Kong Chengrui fu Vladislav Gladkikh Feng ding Centre for Multidimensional Carbon Materials Institute for Basic ScienceUlsanKorea School of Materials Science and Engineering Ulsan National Institute of Science and TechnologyUlsanKorea

The shapes of as‐grown/as‐etched two‐dimensional(2D)islands are the most recognizable features of the chemical vapor deposition(CVD)process which reveal a lot of information about the chemical environment of growth/etching,the effect of the substrate and the growth/etching ***,we summarize experimentally observed shapes of CVD‐grown 2D materials from previous reports,theoretical understanding on the corresponding mechanisms and the simulations of the corresponding growth/etching *** part of the review article is organized by combining the fundamental principles that govern the shapes of crystals during growth/etching and the related experimental observations to facilitate the readers to read and understand the *** content of the review includes attachment‐limited 2D materials growth,diffusion‐limited 2D materials growth(both with and without influence of the substrate),etching and merging of 2D materials with and without considering the effect of the *** also discuss growth and etching of multilayered 2D islands during CVD—a topic still under *** wish this review will also guide the audience to understand the kinetics of 2D materials growth and to improve controllable synthesis of various 2D materials.

关键词： 2D materials chemical vapor deposition growth shape

Tail Autotomy Does Not Increase Locomotor Costs in the Oriental Leaf-toed Gecko Hemidactylus bowringii

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Asian Herpetological Research 2012年第2期3卷 141-146页

作者： Guohua ding Tianbao fu Zongshi ZHOU Xiang JI Jiangsu Key Laboratory for Biodiversity and Biotechnology College of Life Sciences Nanjing Normal University

Tail autotomy is a defense mechanism used by many lizards to evade predators, but it entails costs. We used the oriental leaf-toed gecko Hemidactylus bowringii as a model animal to evaluate locomotor costs of tail autotomy. We removed the tail about 5 mm from the tail base from each of the experimental geckos(adult males) initially having intact tails. Tailless experimental geckos and tailed control geckos were measured for overall speed and sprint speed in both vertical and horizontal directions. Overall speed and sprint speed did not differ between tailless and tailed geckos. The influence of locomotor direction on both overall speed and sprint speed was significant, with horizontal speed being greater than vertical speed. The interaction between tail condition and locomotor direction was not significant in overall speed, but was significant in sprint speed. Tailless geckos had faster vertical sprint speed than the tailed individuals. Of the 130 field-caught adults, 59 had previously lost their tails, with most(about 61%) of them shedding their tails near the tail base. Neither the proportion of geckos with tail autotomy nor the frequency distribution of locations of the tail break differed between the sexes. Our data show that tail loss of H. bowringii occurs frequently in nature. However, tail loss does not incur locomotor costs in this gecko.

关键词： Gekkonidae Hemidactylus bowringii tail autotomy locomotor performance cost of tail autotomy

Assessing Adaptability of Planted Trees Using Leaf Traits: A Case Study with Robinia pseudoacacia L. in the Loess Plateau, China

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Chinese Geographical Science 2011年第3期21卷 290-303页

作者： JIN Tiantian LIU Guohua fu Bojie ding Xiaohui YANG Lei State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

Leaf trait patterns and their variations with climate are interpreted as an adaptive adjustment to *** study assessed the adaptability of planted black locust (Robinia pseudoacacia L.) based on the analysis of leaf traits and the comparison of its leaf traits with inter-specific ones existing in the same *** measured some water and N use related leaf traits: leaf dry mass per unit area (LMA) and N,P and K concentrations based on both leaf area (Narea,Parea and Karea) and leaf mass (Nmass,Pmass and Kmass) of *** at 31 sites along a water stress gradient in North Shaanxi Province,*** results show that leaves of *** have high Nmass and low LMA in the study *** Nmass and low LMA are usually representative of luxurious resource use,and will advance plant resource competitiveness in high-resource *** a whole,LMA-nutrient relationships of *** display patterns that are fairly similar to the inter-specific relationships in both direction and *** tendency for LMA and Narea to increase with decreasing water availability and the positive correlation between LMA and Narea reflect the trend for *** to enhance water use efficiency (WUE) at the expense of down-regulated photosynthetic N use efficiency (PNUE) and high construction cost in dry ***,the positive relationship between LMA and Narea in high mean annual precipitation (MAP) area is either unremarkable or reversed with decreasing water *** implies a lower photosynthetic capacity and a higher construction cost for high-LMA *** inter-specific relationship between LMA and Narea is positive and does not change with water *** difference between inter-species and intra-species may be due to more diversified anatomies and more specialised structures for inter-species than *** failure of *** adaption to dry conditions reflected by LMA-Narea relationship may be partial

关键词： water stress planted tree leaf trait Robinia pseudoacacia L. tradeoff Loess Plateau

A Novel Bio-Based Zirconium Phosphonate as a Flame Retardant and Smoke Suppressant for Epoxy Resin

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Journal of Renewable Materials 2022年第9期10卷 2303-2317页

作者： Xianling fu Hongliang ding Xin Wang Lei Song Yuan Hu State Key Laboratory of Fire Science University of Science and Technology of ChinaHefei230026China

Although epoxy resin has been widely used in various fields,it still suffers from some problems including brittleness and *** this study,a new phosphonic acid,N,N-bis(phosphomethyl)glycine(GDMP),was prepared by Mannich reaction with bio-based glycine and then a novel layered zirconium phosphonate(ZrGDMP)was synthesized using GDMP and zirconyl chloride hydrate as *** chemical structure of ZrGDMP was well characterized by 1 H and 31P NMR,SEM,XRD and *** effect of ZrGDMP on the flame retardancy,smoke suppression,strengthening and toughening performances of the epoxy matrix was investigated and *** results indicated that compared with pure EP,ZrGDMP-EP composites showed higher char yield due to the catalytic charring effect of *** pure EP exhibited high flammability,while ZrGDMP-EP composites possessed excellent thermal stability and remarkable fire *** PHRR,THR,and TSP values of 3wt%ZrGDMP-EP were obviously declined by 39.6%,40.2%,and 24.9%compared to these of pure ***,the tensile and impact tests implied that the addition of ZrGDMP can significantly reinforce the toughness as well as the strength of EP in terms of higher impact strength(24.8 kJ/m^(2))and tensile strength(57.7 MPa),which was mainly contributed to the uniform dispersion of ZrGDMP within the EP matrix.

关键词： Zirconium phosphonate epoxy resin flame retardant mechanical property

Grinding behavior and surface appearance of(TiC_p+ TiB_w)/Ti-6Al-4V titanium matrix composites

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Chinese Journal of Aeronautics 2014年第5期27卷 1334-1342页

作者： ding Wenfeng Zhao Biao Xu Jiuhua Yang Changyong fu Yucan Su Honghua College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology

（TiCp＋ TiBw）/Ti-6Al-4V titanium matrix composites（PTMCs） have broad application prospects in the aviation and nuclear field. However, it is a typical difficult-to-cut material due to high hardness of the reinforcements, high strength and low thermal conductivity of Ti-6Al-4V alloy matrix. Grinding experiments with vitrified CBN wheels were conducted to analyze comparatively the grinding performance of PTMCs and Ti-6Al-4V alloy. Grinding force and force ratios, specific grinding energy, grinding temperature, surface roughness, ground surface appearance were discussed. The results show that the normal grinding force and the force ratios of PTMCs are much larger than that of Ti-6Al-4V alloy. Low depth of cut and high workpiece speed are generally beneficial to achieve the precision ground surface for PTMCs. The hard reinforcements of PTMCs are mainly removed in the ductile mode during grinding. However, the removal phenomenon of the reinforcements due to brittle fracture still exists, which contributes to the lower specific grinding energy and grinding temperature of PTMCs than Ti-6Al-4V alloy.

关键词： Grinding force Grinding temperature Particles Surface appearance Titanium matrix composites

Two-dimensional silicon-carbon hybrids with a honeycomb lattice: New family for two-dimensional photovoltaic materials

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Science China(Physics,Mechanics & Astronomy) 2015年第10期58卷 81-88页

作者： ZHANG Jin REN Jun fu HuiXia ding ZiJing LI Hui MENG Sheng Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Department of Physics Tsinghua University Collaborative Innovation Center of Quantum Matter

We predict a series of new two-dimensional(2D) inorganic materials made of silicon and carbon elements(2D SixC1?x) based on density functional theory. Our calculations on optimized structure, phonon dispersion, and finite temperature molecular dynamics confirm the stability of 2D SixC1?x sheets in a two-dimensional, graphene-like, honeycomb lattice. The electronic band gaps vary from zero to 2.5 e V as the ratio x changes in 2D SixC1?x changes, suggesting a versatile electronic structure in these sheets. Interestingly, among these structures Si0.25C0.75 and Si0.75C0.25 with graphene-like superlattices are semimetals with zero band gap as their ? and ?* bands cross linearly at the Fermi level. Atomic structural searches based on particle-swarm optimization show that the ordered 2D SixC1?x structures are energetically favorable. Optical absorption calculations demonstrate that the 2D silicon-carbon hybrid materials have strong photoabsorption in visible light region, which hold promising potential in photovoltaic applications. Such unique electronic and optical properties in 2D SixC1?x have profound implications in nanoelectronic and photovoltaic device applications.

关键词： 2D Si-C hybrids electronic structure photovoltaic materials first-principles calculations