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Designing of anisotropic gradient surfaces for Directional liquid transport:Fundamentals,construction,and applications

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The Innovation 2023年第6期4卷 115-131页

作者： Lanlan Hou Xiaofei Liu Xinran Ge Rongjun Hu Zhimin Cui Nu WangYong Zhao Key Laboratory of Bioinspired Smart Interfacial Science and Technology of Minitry of Education Beijing Key Laboratory of Bioinspired Energy Materials and DevicesSchool of ChemistryBeijing Advanced Innovation Center for Biomedical EngineeringBeihang UniversityBeijing 100191China School of Printing and Packaging Engineer Beijing Institute of Graphic CommunicationBeiing 102600China Key Laboratory of Photochemical Conversion and Optoelectronic Materials Technical Institute of Physics and ChemistryChinese Academy of SciencesBejjing 100190China Institute of Applied Chemistry Jiangxi Academy of SciencesNanchang 330096China

Many biological surfaces are capable of transporting liquids in a Directional manner without energy consumption.Inspired by nature,constructing asymmetric gradient surfaces to achieve desired droplet transport,such as a liquid diode,brings an incredibly valuable and promising area of research with a wide range of applications.Enabled by advances in nano-technology and manufacturing techniques,biomimetics has emerged as a promising avenue for engineering various types of anisotropic material system.Over the past few decades,this approach has yielded significant progressin both fundamental understanding and practical applications.Theoretical studies revealed that the heterogeneous composition and topography mainly govern the wetting mechanisms and dynamics behavior of droplets,including the interdisciplinary aspects of materials,chemistry,and physics.In this review,we provide a concise overview of various biological surfaces that exhibit anisotropic droplet transport.We discussed the theoretical foundations and mechanisms of droplet motion on designed surfaces and reviewed recent research advances in droplet Directional transport on designed plane surfaces and Janus membranes.Such liquid-diode materials yield diverse promising applications,involving droplet collection,liquid separation and delivery,functional textiles,and biomedical applications.We also discuss the recent challenges and ongoing approaches to enhance the functionality and application performance of anisotropic materials.

关键词： anisotropic Directional gradient

DnaQ mediates Directional spacer acquisition in the CRISPR-Cas system by a time-dependent mechanism

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The Innovation 2023年第5期4卷 78-86页

作者： Dongmei Tang Tingting Jia Yongbo Luo Biqin Mou Jie Cheng Shiqian Qi Shaohua Yao Zhaoming Su Yamei Yu Qiang Chen Department of Urology.State Key Laboratory of Biotherapy West China HospitalSichuan UniversityChengdu 610041China Department of Biotherapy Cancer Center and State Key Laboratory of BioherapyWest China HospitalSichuan UniversiyChengdu 610041China Precision Medicine Center Precision Medicine Key Laboratory of Sichuan ProvinceWest China HospitalSichuan UniversityChengdu 610041China

In the spacer acquisition stage of CRISPR-Cas immunity,spacer orientation and protospacer adjacent motif(PAM)removal are two prerequisites for functional spacer integration.Cas4 has been implicated in both processing the prespacer and determining the spacer orientation.In Cas4-lacking systems,host 3′–5′DnaQ family exonucleases were recently reported to play a Cas4-like role.However,the molecular details of DnaQ functions remain elusive.Here,we characterized the spacer acquisition of the adaptation module of the Streptococcus thermophilus type I-E system,in which a DnaQ domain naturally fuses with Cas2.We presented X-ray crystal structures and cryo-electron microscopy structures of this adaptation module.Our biochemical data showed that DnaQ trimmed PAM-containing and PAM-deficient overhangs with different efficiencies.Based on these results,we proposed a time-dependent model for DnaQ-mediated spacer acquisition to elucidate PAM removal and spacer orientation determination in Cas4-lacking CRISPR-Cas systems.

关键词： details media Directional

Seaweed pattern formation in the non-axially Directional solidification of 2D-like and 3D Al-3 wt.% Mg single crystal

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Journal of Materials Science & Technology 2023年第16期147卷 1-5页

作者： Yumin Wang Bin Yang Shuangming Li Xin Cao Zhongli Liu Hui Xing College of Nuclear Equipment and Nuclear Engineering Yantai UniversityYantai 264005China Inner Mongolia Metal Material Research Institute Yantai 264003China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Shaanxi Key Laboratory of Condensed Matter Structure and PropertiesNorthwestern Polytechnical UniversityXi’an 710129China

1.Introduction Microstructures are at the centre of materials science and engineering and play an essential role in determining the in-service mechanical properties of metallic alloys[1–4].Extensive theoretical and experimental investigations have been undertaken to describe and determine solidification microstructures as a function of solidification conditions.The seaweed pattern is one of the most important classes of microstructural patterns[5–7].The characteristic of this pattern is that its extending tips—unlike the behaviour observed in needle-like dendrites—split repeatedly into two or more parts.

关键词： solidification pattern Directional

Directional H^(2) Compression Algorithm: Optimisations and Application to a Discontinuous Galerkin BEM for the Helmholtz Equation

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Communications in Computational Physics 2022年第5期31卷 1585-1635页

作者： Nadir-Alexandre Messaï Sebastien Pernet Abdesselam Bouguerra ONERA/DTIS Universitéfédérale de Toulouse F-31000 Toulouse France Laboratoire de Physique de la Matière et du Rayonnement(LPMR) Département de Sciences de la MatièreUniversitéde Souk-AhrasBP 155341000 Souk-AhrasAlgeria

This study aimed to specialise a Directional H^(2)(DH^(2))compression to matrices arising from the discontinuous Galerkin(DG)discretisation of the hypersingular equation in acoustics.The significantfinding is an algorithm that takes a DG stiffness matrix andfinds a near-optimal DH^(2) approximation for low and high-frequency problems.We introduced the necessary special optimisations to make this algorithm more efficient in the case of a DG stiffness matrix.Moreover,an automatic parameter tuning strategy makes it easy to use and versatile.Numerical comparisons with a classical Boundary Element Method(BEM)show that a DG scheme combined with a DH^(2) gives better computational efficiency than a classical BEM in the case of high-order finite elements and hp heterogeneous meshes.The results indicate that DG is suitable for an auto-adaptive context in integral equations.

关键词： Integral equation boundary element method Helmholtz equation discontinuous Galerkin Directional H^(2)-matrix low-rank approximation all frequency compression algorithm

Counterintuitive Ballistic and Directional Liquid Transport on a Flexible Droplet Rectifier

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Research 2020年第1期2020卷 1009-1019页

作者： Lei Wang Jing Li Bo Zhang Shile Feng Mei Zhang Dong Wu Yang Lu Ji Jung Kai Jing Liu Zuankai Wang Lei Jiang Beijing Key Lab of Cryo-Biomedical Engineering and Key Lab of Cryogenics Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190China Department of Mechanical Engineering City University of Hong KongHong Kong 999077China Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education School of ChemistryBeijing Advanced Innovation Center for Biomedical EngineeringBeihang UniversityBeijing 100191China CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Precision Machinery and Precision InstrumentationUniversity of Science and Technology of ChinaHefeiAnhui 230027China

Achieving the Directional and long-range droplet transport on solid surfaces is widely preferred for many practical applications but has proven to be challenging.Particularly,Directionality and transport distance of droplets on hydrophobic surfaces are mutually exclusive.Here,we report that drain fly,a ubiquitous insect maintaining nonwetting property even in very high humidity,develops a unique ballistic droplet transport mechanism to meet these demanding challenges.The drain fly serves as a flexible rectifier to allow for a Directional and long-range propagation as well as self-removal of a droplet,thus suppressing unwanted liquid flooding.Further investigation reveals that this phenomenon is owing to the synergistic conjunction of multiscale roughness,structural periodicity,and flexibility,which rectifies the random and localized droplet nucleation(nanoscale and microscale)into a directed and global migration(millimeter-scale).The mechanism we have identified opens up a new approach toward the design of artificial rectifiers for broad applications.

关键词： Directional mechanism roughness

Directional Design of Materials Based on Multi-Objective Optimization:A Case Study of Two-Dimensional Thermoelectric SnSe

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Chinese Physics Letters 2021年第2期38卷 84-90页

作者：闫申申汪毅高志斌龙洋任捷 Center for Phononics and Thermal Energy Science China-EU Joint Lab on NanophononicsShanghai Key Laboratory of Special Artificial Microstructure Materials and TechnologySchool of Physics Science and EngineeringTongji UniversityShanghai 200092China Department of Physics National University of SingaporeSingapore 117551Republic of Singapore Shanghai Research Institute for Intelligent Autonomous Systems Tongji UniversityShanghai 200092China

The Directional design of functional materials with multi-objective constraints is a big challenge,in which performance and stability are determined by a complicated interconnection of different physical factors.We apply multi-objective optimization,based on the Pareto Efficiency and Particle-Swarm Optimization methods,to design new functional materials Directionally.As a demonstration,we achieve the thermoelectric design of 2D SnSe materials via the above methods.We identify several novel metastable 2D SnSe structures with simultaneously lower free energy and better thermoelectric performance in their experimentally reported monolayer structures.We hope that the results of our work on the multi-objective Pareto Optimization method will represent a step forward in the integrative design of future multi-objective and multi-functional materials.

关键词： materials. methods. Directional

Microstructure evolution, Cu segregation and tensile properties of CoCrFeNiCu high entropy alloy during Directional solidification

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Journal of Materials Science & Technology 2020年第3期38卷 19-27页

作者： Huiting Zheng Ruirun Chen Gang Qin Xinzhong Li Yanqing Su Hongsheng Ding Jingjie Guo Hengzhi Fu National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of TechnologyHarbin 150001China State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China

CoCrFeNiCu(equiatomic ratio)samples(?8 mm)were Directionally solidified at different velocities(10,30,60 and 100μm/s)to investigate the relationship between solidification velocity and microstructure formation,Cu micro-segregation as well as tensile properties.The results indicate that the morphology of the solid-liquid(S-L)interface evolves from convex to planar and then to concave with the increase of solidification velocity.Meanwhile,the primary and the secondary dendritic arm spacings decrease from100μm to 10μm and from 20μm to 5μm,respectively.They are mainly influenced by the axial heat transfer and grain competition growth.During Directional solidification,element Cu is repelled from the FCC phase and accumulates in the liquid owe to its positive mixing enthalpy with other elements.Tensile testing results show that the ultimate tensile strength(UTS)gradually increases from 400 MPa to 450 MPa,and the strain of the specimen prepared at the velocity of 60μm/s is higher than those of others.The fracture mode of all specimens is the mixed fracture containing both ductile fracture and brittle fracture,in which ductile fracture plays a fundamental role.In addition,the brittle fracture is induced by Cu segregation.The improvement of UTS is resulted from columnar grain boundary strengthening.

关键词： High entropy alloy Directional solidification Segregation Tensile properties

In-situ observation of solid-liquid interface transition during Directional solidification of Al-Zn alloy via X-ray imaging

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Journal of Materials Science & Technology 2020年第4期39卷 113-123页

作者： Yuanhao Dong Sansan Shuai Tianxiang Zheng Jiawei Cao Chaoyue Chen Jiang Wang Zhongming Ren State Key Laboratory of Advanced Special Steel School of Materials Science and EngineeringShanghai UniversityShanghai 200444China

The morphological instability of solid/liquid(S/L)interface during solidification will result in different patterns of microstructure.In this study,two dimension(2 D)and three dimension(3 D)in-situ observation of solid/liquid interfacial morphology transition in Al-Zn alloy during Directional solidification were performed via X-ray imaging.Under a condition of increasing temperature gradient(G),the interface transition from dendritic pattern to cellular pattern,and then to planar growth with perturbation was captured.The effect of solidification parameter(the ratio of temperature gradient and growth velocity(v),G/v)on morphological instabilities was investigated and the experimental results were compared to classical"constitutional supercooling"theory.The results indicate that 2 D and 3 D evolution process of S/L interface morphology under the same thermal condition are different.It seems that the S/L interface in 2 D observation is easier to achieve planar growth than that in 3 D,implying higher S/L interface stability in 2 D thin plate samples.This can be explained as the restricted liquid flow under 2 D solidification which is beneficial to S/L interface stability.The in-situ observation in present study can provide coherent dataset for microstructural formation investigation and related model validation during solidification.

关键词： Al-Zn alloy Directional solidification Solid/liquid interface instability In-situ observation X-ray imaging

Cellulose Microfibril-Mediated Directional Plant Cell Expansion:Gas and Brake

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Molecular Plant 2020年第12期13卷 1670-1672页

作者： Ying Wang Yuling Jiao College of Life Sciences University of Chinese Academy of SciencesBeijing 100049China State Key Laboratory of Plant Genomics and National Center for Plant Gene Research(Beijing) Institute of Genetics and Developmental BiologyThe Innovative Academy of Seed DesignChinese Academy of SciencesBeijing 100101China College of Advanced Agricultural Sciences University of Chinese Academy of SciencesBeijing 100049China

Directional cell expansion is a fundamental process that is involved in virtually all cellular processes.Divergence from isotropic growth is commonly associated with cell fate transition,organ shaping,or cell maturation.To obtain continuous direc-tional cell growth,and tissue and organ growth as well,positive feedback loops are needed to lock anisotropic cell expansion.On the other hand,antagonistic mechanisms are needed to terminate Directional cell expansion.Many genes affecting cell shape have been identified,but only in a few cases do we under-stand the precise chains of molecular events to some extent.Recently,a cortical microtubule(CMT)-mediated mechanical feedback loop has been recognized that amplifies tensile stress anisotropy and leads to expansion perpendicular to the stress di-rection(Sampathkumar,2020;Zhao et al.,2020)(Figure 1A).By contrast,passive reorientation of cellulose microfibrils(CMFs)may form a combative mechanism that cancels Directional cell expansion(Figure 1B).However,passive CMF reorientation is insufficiently recognized by developmental biologists who are interested in Directional cell expansion,anisotropic tissue growth,and organ shaping.

关键词： Figure expansion Directional