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Journal of Bionic Engineering 2008年第4期5卷 271-281页

作者： y.y. yan C.y. Ji School of the Built Environment University of Nottingham Nottingham NG7 2RD UK

This paper presents a molecular dynamics simulation of the behaviours of non-polar droplets merging and also the fluid molecules interacting with a hydrophobic surface. Such behaviours and transport phenomena are popular in general microchannel flow boiling and two-phase flow. The droplets are assumed to be composed of Lennards-Jones type molecules. Periodic boundary conditions are applied in three coordinate directions of a 3-D system, where there exist two liquid droplets and their vapour. The two droplets merge when they come within the prescribed small distance. The merging of two droplets apart from each other at different initial distances is tested and the possible larger （or critical） non-dimensional distance, in which droplets merging can occur, is discussed. The evolution of the merging process is simulated numerically by employing the Molecular Dynamics （MD） method. For interactions with hydrophobic solid wall, a system with fluid confined between two walls is used to study the wetting phenomena of fluid and solid wall. The results are compared with those of hydrophilic wall to show the unique characteristics of hydrophobic interactions by microscopic methods.

关键词： molecular dynamics simulation mist flow droplets merging hydrophobic wetting

Simulation of plastic deformation induced texture evolution using the crystallographic homogenization finite element method

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Acta Mechanica Solida Sinica 2017年第1期30卷 51-63页

作者： y.P.Chen y.y.Cai Department of Mechanics Huazhong University of Science and Technology

A semi-implicit elastic/crystalline viscoplastic finite element（FE） method based on a ＂crystallographic homogenization＂ approach is formulated for a multi-scale analysis. In the formulation, the asymptotic series expansion is introduced to define the displacement in the micro-continuum. This homogenization FE analysis is aimed at predicting the plastic deformation induced texture evolution of polycrystalline materials, the constituent microstructure of which is represented by an assembly of single crystal grains. The rate dependent crystal plasticity model is adopted for the description of microstructures. Their displacements are decomposed into two parts： the homogenized deformation defined in the macrocontinuum and the perturbed one in the micro-continuum. This multi-scale formulation makes it possible to carry out an alternative transition from a representative micro-structure to the macro-continuum. This homogenization procedure satisfies both the compatibility and the equilibrium in the micro-structure. This developed code is applied to predict the texture evolution, and its performance is demonstrated by the numerical examples of texture evolution of FCC polycrystalline metals.

关键词： Homogenization Local periodicity Crystalline plasticity Texture Finite element

Reinventing MoS2 Co-catalytic Fenton reaction:Oxygen-incorporation mediating surface superoxide radical generation

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Nano Research 2022年第3期15卷 1973-1982页

作者： Xianjun tan Wenhui Ding Zhenying Jiang Linxiao Sun yuxiong Huang Environmental Science and New Energy Technology Research Center Tsinghua-Berkeley Shenzhen Institute(TBSI)Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China

To better understand the mechanisms of hydrogen peroxide(H_(2)O_(2))’s decomposition and reactive oxygen species(ROS)’s formation on the catalyst’s surface is always a critical issue for the environmental application of Fenton/Fenton-like *** here report a new approach to activate H_(2)O_(2) in a co-catalytic Fenton system with oxygen incorporated MoS2,namely MoS_(2−x) O_(x) *** MoS_(2−x) O_(x) nanosheets assisted co-catalytic Fenton system exhibited superior degradation activity of emerging antibiotic contaminants(e.g.,sulfamethoxazole).Combining density functional theory(DFT)calculation and experimental investigation,we demonstrated that oxygen incorporation could improve the intrinsic conductivity of MoS_(2−x) O_(x) nanosheets and accelerate surface/interfacial charge transfer,which further leads to the efficacious activation of H_(2)O_(2).Moreover,by tuning the oxygen proportion in MoS_(2−x) O_(x) nanosheets,we are able to modulate the generation of ROS and further direct the oriented-conversion of H_(2)O_(2) to surface-bounded superoxide radical(·O_(2−surface)).It sheds light on the generation and transformation of ROS in the engineered system(e.g.,Fenton,Fenton-like reaction)for efficient degradation of persistent pollutants.

关键词： Co-catalytic Fenton reaction MoS2 nanosheets reactive oxygen species(ROS) superoxide radical antibiotics’degradation

Directionally tailoring micro-nano hierarchical tower structured Mn_(0.6)Ni_(1.4)Co_(2)O_(y) toward solar interfacial evaporation

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Journal of Materials Science & Technology 2023年第27期158卷 21-30页

作者： yi Zhang Shujuan tan Tong Xu Zhuoting Zhou Guanbgin Ji College of Materials Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Solar interfacial evaporation has been considered as a promising method to alleviate fresh water re-sources *** shortage of freshwater resources requires advanced materials that can accelerate the evaporation of water by the ***,the simple structure of photothermal materials are vitally restricted by finite light ***,this work presents a strategy for the synthesis of a spinel-type micro-nano hierarchical tower structure solar absorbent(Mn_(0.6)Ni_(1.4)Co_(2)O_(y))with the low forbidden band(=1.56 eV)and high absorption(97.88%).The products show great potential in solar-thermal energy conversion by creating a trapping *** prepared solar absorbent and epoxy resin are evenly mixed and then fully immersed in polyurethane(PU)sponge for water *** hydrophilic and porous Mn_(0.6)Ni_(1.4)Co_(2)O_(y)@PU sponge can quickly deliver water upwards,suppress the heat loss,and concentrate the absorbed heat on the evaporation of *** products exhibited an excellent evaporation rate of 2.261 kg m^(-2) h^(-1) and an impressive evaporation efficiency of 156%under a single sun ***,the samples also can maintain the stability and recycling performance for a long *** findings show that Mn_(0.6)Ni_(1.4)Co_(2)O_(y) have great application prospects in the solar interfacial evaporation.

关键词： Solar interfacial evaporation Photothermal conversion Spinel Micro-nano hierarchical structure

Bioinspired Multiscale Wrinkling Patterns on Curved Substrates:An Overview

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Nano-Micro Letters 2020年第8期12卷 130-171页

作者： yinlong tan Biru Hu Jia Song Zengyong Chu Wenjian Wu College of Liberal Arts and Science National University of Defense TechnologyChangsha 410073People’s Republic of China

The surface wrinkling of biological tissues is ubiquitous in *** evidence suggests that the mechanical force plays a significant role in shaping the biological *** wrinkling has been demonstrated to be able to spontaneously form rich multiscale patterns,on either planar or curved *** surface wrinkling on planar substrates has been investigated thoroughly during the past ***,most wrinkling morphologies in nature are based on the curved biological surfaces and the research of controllable patterning on curved substrates still remains *** study of wrinkling on curved substrates is critical for understanding the biological growth,developing threedimensional(3D)or four-dimensional(4D)fabrication techniques,and creating novel topographic *** this review,fundamental wrinkling mechanics and recent advances in both fabrications and applications of the wrinkling patterns on curved substrates are *** mechanics behind the wrinkles is compared between the planar and the curved *** the film thickness,modulus ratio,and mismatch strain,the substrate curvature is one more significant parameter controlling the surface *** substrates can be both solid and hollow with various 3D geometries across multiple length *** to date,the wrinkling morphologies on solid/hollow core-shell spheres and cylinders have been simulated and selectively *** applications of the curved topographic patterns have been found in smart wetting surfaces,cell culture interfaces,healthcare materials,and actuators,which may accelerate the development of artificial organs,stimuli-responsive devices,and micro/nano fabrications with higher dimensions.

关键词： Surface instability Wrinkling patterns Substrate curvature Micro/nano fabrications Low-dimensional materials

Demonstration of the approximation of eliminating atomic excited populations in an atom-cavity system

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Chinese Physics B 2012年第2期21卷 272-277页

作者： Zhang yu-Qing Huang Gang tan Lei Institute of Theoretical Physics Lanzhou UniversityLanzhou 730070China Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education Lanzhou UniversityLanzhou 730000China

Using the master equation approach to a V-type three-level atom inside a high-finesse single-mode cavity in the strong coupling condition, we demonstrate the approximation of eliminating populations of atomic excited states, which is widely used in the field of the atom cavity systems [Hechenblaikner G, Gangl M, Horak P and Ritsch H 1998 Phys. Rev. A 58 3030]; Liu L W, tan T and Xu y 2008 J. Mod. Opt. 56 968; Cho J, Angelakis D G and Bose S 2008 Phys. Rev. A 78 062338. This is reflected in the deviation of the population 5, of which the value is 10^-3 - 10^-2. We further find the deviation of the dipole force and demonstrate that the deviation of atomic population will not notably affect the dipole force of the atom in the strong coupling condition. A relevant experimental case is also presented.

关键词： V-type three-level atom high finesse optical cavity dipole force strong coupling condition

Recent Advances in Computational Simulation of Macro-,Meso-,and Micro-Scale Biomimetics Related Fluid Flow Problems

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Journal of Bionic Engineering 2007年第2期4卷 97-107页

作者： y. y. yan School of the Built Environment The University of Nottingham Nottingham NG7 2RD UK

Over the last decade, computational methods have been intensively applied to a variety of scientific researches and engineering designs. Although the computational fluid dynamics （CFD） method has played a dominant role in studying and simulating transport phenomena involving fluid flow and heat and mass transfers, in recent years, other numerical methods for the simulations at meso- and micro-scales have also been actively applied to solve the physics of complex flow and fluid-interface interactions. This paper presents a review of recent advances in multi-scale computational simulation of biomimetics related fluid flow problems. The state-of-the-art numerical techniques, such as lattice Boltzmann method （LBM）, molecular dynamics （MD）, and conventional CFD, applied to different problems such as fish flow, electro-osmosis effect of earthworm motion, and self-cleaning hydrophobic surface, and the numerical approaches are introduced. The new challenging of modelling biomimetics problems in developing the physical conditions of self-clean hydrophobic surfaces is discussed.

关键词： biomimetics computational simulation macro- meso- micro-scale hydrophobic surfaces

Collaborative visual SLAM for multiple agents:A brief survey

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Virtual Reality & Intelligent Hardware 2019年第5期1卷 461-482页

作者： Danping ZOU Ping tan Wenxian yU Shanghai Key Laboratory of Navigation and Location-Based Services Shanghai Key Laboratory of Intelligent Sensing and RecognitionShanghai Jiao Tong UniversityShanghai 200240China School of Computing Science Simon Fraser UniversityBurnaby V5A 1S6Canada

This article presents a brief survey to visual simultaneous localization and mapping (SLAM) systems applied to multiple independently moving agents, such as a team of ground or aerial vehicles, a group of users holding augmented or virtual reality devices. Such visual SLAM system, name as collaborative visual SLAM, is different from a typical visual SLAM deployed on a single agent in that information is exchanged or shared among different agents to achieve better robustness, efficiency, and accuracy. We review the representative works on this topic proposed in the past ten years and describe the key components involved in designing such a system including collaborative pose estimation and mapping tasks, as well as the emerging topic of decentralized architecture. We believe this brief survey could be helpful to someone who are working on this topic or developing multi-agent applications, particularly micro-aerial vehicle swarm or collaborative augmented/virtual reality.

关键词： Visual SLAM Multiple agent UAV swarm Collaborative AR/VR

A New Pre-alignment Approach Based on Four-Quadrant-Photo-Detector for IC Mask

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International Journal of Automation and computing 2007年第2期4卷 208-216页

作者： yun Liu De Xu Min tan The Key Laboratory of Complex Systems and Intelligence Science Institute of Automation CAS Beijing 100080. PRC

In this paper, a new pre-alignment approach based on Four-Quadrant-Photo-Detector （FQPD） for IC mask is presented. The voltage outputs from FQPDs are the functions of alignment mark＇s position offsets with respect to FQPDs. The functions are obtained with least squares error （LSE）-based polynomial fitting after the normalization of experimental data. As the acquired functions are not monotonic about their variables, the alignment mark＇s position offset cannot be given by direct inverse operation on the obtained functions. However, the piecewise polynomial fitting gives the inverse function, with which the alignment mark＇s position offset can be predicted according to the voltage outputs of FQPDs. On the basis of prediction, a pre-alignment control strategy is proposed. The feasibility and robustness of the pre-alignment approach is shown by experiments. Furthermore, the results demonstrate that the maximum error of mask＇s position offset in the X- and y- directions is less than 15μm after coarse pre-alignment. Keywords： Four-Quadrant-Photo-Detector （FQPD）, pre-alignment, IC mask, polynomial fitting

关键词： Four-Quadrant-Photo-Detector (FQPD) pre-alignment IC mask polynomial fitting.

Investigating the impact of dynamic structural changes of Au/rutile catalysts on the catalytic activity of CO oxidation

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Carbon Energy 2024年第4期6卷 222-232页

作者： Xiaochun Hu Qianwenhao Fan Mingwu tan yuqing Luo Xianyue Wu Manoel y.Manuputty Jie Ding Tej S.Choksi Markus Kraft Rong Xu Zhiqiang Sun Wen Liu School of Energy Science and Engineering Central South UniversityChangshaChina School of Chemistry Chemical Engineering and BiotechnologyNanyang Technological UniversitySingaporeSingapore Cambridge Centre for Advanced Research and Education SingaporeSingapore Institute of Sustainability for Chemicals Energy and EnvironmentJurong IslandSingapore College of Chemistry and Chemical Engineering Central South UniversityChangshaChina Department of Chemical Engineering and Biotechnology University of CambridgeCambridgeUK

The surface properties of oxidic supports and their interaction with the supported metals play critical roles in governing the catalytic activities of oxide‐supported metal *** metals are supported on reducible oxides,dynamic surface reconstruction phenomena,including strong metal–support interaction(SMSI)and oxygen vacancy formation,complicate the determination of the structural–functional relationship at the active ***,we performed a systematic investigation of the dynamic behavior of Au nanocatalysts supported on flame‐synthesized TiO_(2),which takes predominantly a rutile phase,using CO oxidation above room temperature as a probe *** analysis conclusively elucidated a negative correlation between the catalytic activity of Au/TiO_(2) and the oxygen vacancy at the Au/TiO_(2) *** the reversible formation and retracting of SMSI overlayers have been ubiquitously observed on Au/TiO_(2) samples,the catalytic consequence of SMSI remains *** functional theory suggests that the electron transfer from TiO_(2) to Au is correlated to the presence of the interfacial oxygen vacancies,retarding the catalytic activation of CO oxidation.

关键词： CO oxidation electronic metal-support interactions flame‐synthesis metal-support interactions oxygen vacancy strong metal-support interaction