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Li T, Li Y. 3D Tiled Auxetic Metamaterial: A New Family of Mechanical Metamaterial with High Resilience and Mechanical Hysteresis. Adv Mater 2024; 36:e2309604. [PMID: 38183315 DOI: 10.1002/adma.202309604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Revised: 11/28/2023] [Indexed: 01/08/2024]
Abstract
For artificial materials, desired properties often conflict. For example, engineering materials often achieve high energy dissipation by sacrificing resilience and vice versa, or desired auxeticity by losing their isotropy, which limits their performance and applications. To solve these conflicts, a strategy is proposed to create novel mechanical metamaterial via 3D space filling tiles with engaging key-channel pairs, exemplified via auxetic 3D keyed-octahedron-cuboctahedron metamaterials. This metamaterial shows high resilience while achieving large mechanical hysteresis synergistically under large compressive strain. Especially, this metamaterial exhibits ideal isotropy approaching the theoretical limit of isotropic Poisson's ratio, -1, as rarely seen in existing 3D mechanical metamaterials. In addition, the new class of metamaterials provides wide tunability on mechanical properties and behaviors, including an unusual coupled auxeticity and twisting behavior under normal compression. The designing methodology is illustrated by the integral of numerical modeling, theoretical analysis, and experimental characterization. The new mechanical metamaterials have broad applications in actuators and dampers, soft robotics, biomedical materials, and engineering materials/systems for energy dissipation.
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Affiliation(s)
- Tiantian Li
- Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA02115, USA
| | - Yaning Li
- Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA02115, USA
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2
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Wang C, Lei Y, Li C. Achieving an Excellent Strength and Ductility Balance in Additive Manufactured Ti-6Al-4V Alloy through Multi-Step High-to-Low-Temperature Heat Treatment. Materials (Basel) 2023; 16:6947. [PMID: 37959543 PMCID: PMC10648098 DOI: 10.3390/ma16216947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 10/27/2023] [Accepted: 10/27/2023] [Indexed: 11/15/2023]
Abstract
Selective laser melting (SLM) can effectively replace traditional processing methods to prepare parts with arbitrary complex shapes through layer-by-layer accumulation. However, SLM Ti-6Al-4V alloy typically exhibits low ductility and significant mechanical properties anisotropy due to the presence of acicular α' martensite and columnar prior β grains. Post-heat treatment is frequently used to obtain superior mechanical properties by decomposing acicular α' martensite into an equilibrium α + β phase. In this study, the microstructure and tensile properties of SLM Ti-6Al-4V alloy before and after various heat treatments were systematically investigated. The microstructure of the as-fabricated Ti-6Al-4V sample was composed of columnar prior β grains and acicular α' martensite, which led to high strength (~1400 MPa) but low ductility (~5%) as well as significantly tensile anisotropy. The single heat treatment samples with lamellar α + β microstructure exhibited improved elongation to 6.8-13.1% with a sacrifice of strength of 100-200 MPa, while the tensile anisotropy was weakened. A trimodal microstructure was achieved through multi-step high-to-low-temperature (HLT) heat treatment, resulting in an excellent combination of strength (~1090 MPa) and ductility (~17%), while the tensile anisotropy was almost eliminated. The comprehensive mechanical properties of the HLT samples were superior to that of the conventional manufactured Ti-6Al-4V alloy.
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Affiliation(s)
| | - Yan Lei
- School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China;
| | - Chenglin Li
- School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China;
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3
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Zawadzki P, Talar R, Grochalski K, Dąbrowski M. The Influence of Osteon Orientation on Surface Topography Parameters after Machining of Cortical Bone Tissue. Materials (Basel) 2023; 16:4293. [PMID: 37374480 DOI: 10.3390/ma16124293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 05/22/2023] [Accepted: 06/05/2023] [Indexed: 06/29/2023]
Abstract
Mechanical processing of cortical bone tissue is one of the most common surgical procedures. A critical issue accompanying this processing is the condition of the surface layer, which can stimulate tissue growth and serve as a drug carrier. A comparison of the surface condition before and after orthogonal and abrasive processing was conducted to validate the influence of bone tissue's processing mechanism and orthotropic properties on the surface topography. A cutting tool with a defined geometry and a custom-made abrasive tool was used. The bone samples were cut in three directions, depending on the orientation of the osteons. The cutting forces, acoustic emission, and surface topography were measured. The level of isotropy and the topography of the grooves showed statistical differences relative to the anisotropy directions. After orthogonal processing, the surface topography parameter Ra was determined from 1.38 ± 0.17 μm to 2.82 ± 0.32. In the case of abrasive processing, no correlation was found between the orientation of osteons and topographical properties. The average groove density for abrasive machining was below 1004 ± 0.7, and for orthogonal, it was above 1156 ± 58. Due to the positive properties of the developed bone surface, it is advisable to cut in the transverse direction and parallel to the axis of the osteons.
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Affiliation(s)
- Paweł Zawadzki
- Faculty of Mechanical Engineering, Poznan University of Technology, Maria Sklodowska-Curie Square 5, 60-965 Poznan, Poland
| | - Rafał Talar
- Faculty of Mechanical Engineering, Poznan University of Technology, Maria Sklodowska-Curie Square 5, 60-965 Poznan, Poland
| | - Karol Grochalski
- Faculty of Mechanical Engineering, Poznan University of Technology, Maria Sklodowska-Curie Square 5, 60-965 Poznan, Poland
| | - Mikołaj Dąbrowski
- Adult Spine Orthopaedics Department, Poznan University of Medical Sciences, 61-545 Poznan, Poland
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Wang Y, Xu F, Gao H, Li X. Elastically Isotropic Truss-Plate-Hybrid Hierarchical Microlattices with Enhanced Modulus and Strength. Small 2023; 19:e2206024. [PMID: 36748308 DOI: 10.1002/smll.202206024] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 01/03/2023] [Indexed: 05/04/2023]
Abstract
Bioinspired hierarchical design principles have been employed to create advanced architected materials. Here, a new type of truss-plate-hybrid two-level hierarchical architecture is created, referred to as the ISO-COP hierarchical lattice (isotropic truss at the first level and cubic+octet plate at the second level), in which truss-based unit cells are arranged according to the topology of the plate-based unit cell. Finite element analyses reveal that the ISO-COP hierarchical lattice outperforms the best existing octet-truss hierarchical lattices based on fractal geometries in achieving elastic isotropy and enhanced moduli. According to the designed architecture, ISO-COP and several other comparison hierarchical microlattices are fabricated via projection microstereolithography. In situ compression tests demonstrate that the fabricated ISO-COP microlattices exhibit elastic isotropy and enhanced moduli, as predicted from finite element simulations, and superior strength compared with existing fractal octet-truss hierarchical lattices. Theoretical models are further developed to predict the dependence of modulus and failure modes on two design parameters of the hierarchical lattices, with results in good agreement with those from experiments. This study relates mechanical properties of ISO-COP hierarchical lattices to their architectures at each level of hierarchy and exemplifies a route to harnessing hierarchical design principles to create architected materials with desired mechanical properties.
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Affiliation(s)
- Yujia Wang
- Centre for Advanced Mechanics and Materials, Applied Mechanics Laboratory, Department of Engineering Mechanics, Tsinghua University, Beijing, 100084, P. R. China
| | - Fan Xu
- Institute of Mechanics and Computational Engineering, Department of Aeronautics and Astronautics, Fudan University, Shanghai, 200433, P. R. China
| | - Huajian Gao
- School of Mechanical and Aerospace Engineering, College of Engineering, Nanyang Technological University, 70 Nanyang Drive, Singapore, 639798, Singapore
- Institute of High Performance Computing, Agency for Science, Technology and Research (A*STAR), Singapore, 138632, Singapore
| | - Xiaoyan Li
- Centre for Advanced Mechanics and Materials, Applied Mechanics Laboratory, Department of Engineering Mechanics, Tsinghua University, Beijing, 100084, P. R. China
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5
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Hall JK, Bates JHT, Casey DT, Bartolák-Suki E, Lutchen KR, Suki B. Predicting alveolar ventilation heterogeneity in pulmonary fibrosis using a non-uniform polyhedral spring network model. Front Netw Physiol 2023; 3:1124223. [PMID: 36926543 PMCID: PMC10013074 DOI: 10.3389/fnetp.2023.1124223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 01/20/2023] [Indexed: 02/04/2023]
Abstract
Pulmonary Fibrosis (PF) is a deadly disease that has limited treatment options and is caused by excessive deposition and cross-linking of collagen leading to stiffening of the lung parenchyma. The link between lung structure and function in PF remains poorly understood, although its spatially heterogeneous nature has important implications for alveolar ventilation. Computational models of lung parenchyma utilize uniform arrays of space-filling shapes to represent individual alveoli, but have inherent anisotropy, whereas actual lung tissue is isotropic on average. We developed a novel Voronoi-based 3D spring network model of the lung parenchyma, the Amorphous Network, that exhibits more 2D and 3D similarity to lung geometry than regular polyhedral networks. In contrast to regular networks that show anisotropic force transmission, the structural randomness in the Amorphous Network dissipates this anisotropy with important implications for mechanotransduction. We then added agents to the network that were allowed to carry out a random walk to mimic the migratory behavior of fibroblasts. To model progressive fibrosis, agents were moved around the network and increased the stiffness of springs along their path. Agents migrated at various path lengths until a certain percentage of the network was stiffened. Alveolar ventilation heterogeneity increased with both percent of the network stiffened, and walk length of the agents, until the percolation threshold was reached. The bulk modulus of the network also increased with both percent of network stiffened and path length. This model thus represents a step forward in the creation of physiologically accurate computational models of lung tissue disease.
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Affiliation(s)
- Joseph K Hall
- Department of Biomedical Engineering, Boston University, Boston, MA, United States
| | - Jason H T Bates
- Department of Medicine, University of Vermont, Burlington, VT, United States
| | - Dylan T Casey
- Complex Systems Center, University of Vermont, Burlington, VT, United States
| | | | - Kenneth R Lutchen
- Department of Biomedical Engineering, Boston University, Boston, MA, United States
| | - Béla Suki
- Department of Biomedical Engineering, Boston University, Boston, MA, United States
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6
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Li W, Zhang Q, Yang Z, Ji H, Wu T, Wang H, Cai Z, Xie C, Li Y, Wang H. Isotropic Amorphous Protective Layer with Uniform Interfacial Zincophobicity for Stable Zinc Anode. Small 2022; 18:e2205667. [PMID: 36373682 DOI: 10.1002/smll.202205667] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 10/20/2022] [Indexed: 06/16/2023]
Abstract
Aqueous zinc-ion batteries (AZIBs) have drawn the attention of numerous researchers owing to their high safety and cost-effectiveness. However, the dendrite growth and side reactions of the zinc (Zn) anodes limit their further practical applications. Herein, a porous amorphous silicon nitride protective layer with high zincophobicity is constructed on the Zn anode surface, which can guide the uniform stripping/plating of Zn2+ underneath the protective layer through its isotropic Zn affinity to alleviate the growth of dendrites and by-products. As a result, the amorphous silicon nitride-protected Zn anode can maintain a stable Coulombic efficiency (CE) of 98.8% and low voltage hysteresis for 710 cycles in the half cell. The full cell with the as-prepared Zn anode can deliver excellent electrochemical performances (89.0% capacity retention and 144.4 mAh g-1 discharge capacity after 1000 cycles at 4 A g-1 ). This work reveals the key role of uniform metal affinity induced by the amorphous materials in the interface modification of metal anodes, which is instructive for the design of stable metal anodes.
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Affiliation(s)
- Wenbin Li
- Hunan Provincial Key Laboratory of Chemical Power Sources, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, P. R. China
| | - Qi Zhang
- Hunan Provincial Key Laboratory of Chemical Power Sources, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, P. R. China
| | - Zefang Yang
- Hunan Provincial Key Laboratory of Chemical Power Sources, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, P. R. China
| | - Huimin Ji
- Hunan Provincial Key Laboratory of Chemical Power Sources, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, P. R. China
| | - Tingqing Wu
- Hunan Provincial Key Laboratory of Chemical Power Sources, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, P. R. China
| | - Hao Wang
- Hunan Provincial Key Laboratory of Chemical Power Sources, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, P. R. China
| | - Zhiwen Cai
- Hunan Provincial Key Laboratory of Chemical Power Sources, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, P. R. China
| | - Chunlin Xie
- Hunan Provincial Key Laboratory of Chemical Power Sources, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, P. R. China
| | - Yixin Li
- Hunan Provincial Key Laboratory of Chemical Power Sources, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, P. R. China
| | - Haiyan Wang
- Hunan Provincial Key Laboratory of Chemical Power Sources, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, P. R. China
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7
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Wang J, Hu S, Yang B, Jin G, Zhou X, Lin X, Wang R, Lu Y, Zhang L. Novel Three-Dimensional-Printing Strategy Based on Dynamic Urea Bonds for Isotropy and Mechanical Robustness of Large-Scale Printed Products. ACS Appl Mater Interfaces 2022; 14:1994-2005. [PMID: 34963290 DOI: 10.1021/acsami.1c20659] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Additive manufacturing via fused deposition modeling (FDM) has become one of the most widely used technologies owing to its ease of operation and effective cost. However, the disappointing interlayer adhesion produced by FDM often results in inferior mechanical properties, which has become a technical bottleneck for industrial production. Herein, we demonstrate a facile and efficient printing strategy to enhance interlayer adhesion by introducing a self-healing mechanism into the printing material, thereby concurrently enhancing the mechanical properties and isotropy of the printed products. This strategy relies on the self-healing property of three-dimensional-printing materials. This self-healing property is endowed by introducing dynamic urea bonds on the thermoplastic polyurethane (TPU) molecular chains, and then, such dynamic bonds can be activated through thermal heating. Accordingly, the synthesized TPU reveals an efficient self-healing property and excellent printability owing to the existence of dynamic reversible covalent bonds. Moreover, objects with complex structures can be split and printed and then assembled using this strategy, avoiding the need for supporting structures and realizing the rapid prototyping of large-sized objects. The printing strategy proposed paves a candidate way to overcome the current challenges in obtaining high-quality products via FDM.
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Affiliation(s)
- Jun Wang
- Key Laboratory of Beijing City for Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, China
| | - Shikai Hu
- Key Laboratory of Beijing City for Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, China
| | - Bin Yang
- Key Laboratory of Beijing City for Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, China
| | - Guangzhi Jin
- Key Laboratory of Beijing City for Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, China
| | - Xinxin Zhou
- Key Laboratory of Beijing City for Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, China
| | - Xiang Lin
- School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Runguo Wang
- Key Laboratory of Beijing City for Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, China
| | - Yonglai Lu
- Key Laboratory of Beijing City for Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, China
| | - Liqun Zhang
- Key Laboratory of Beijing City for Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, China
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8
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Baselga A, Gómez-Rodríguez C. Assessing the equilibrium between assemblage composition and climate: A directional distance-decay approach. J Anim Ecol 2021; 90:1906-1918. [PMID: 33909913 DOI: 10.1111/1365-2656.13509] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 04/23/2021] [Indexed: 11/27/2022]
Abstract
The variation of assemblage composition in space is characterised by the decrease in assemblage similarity with spatial distance. Climatic constraint and dispersal limitation are major drivers of distance-decay of similarity. Distance-decay of similarity is usually conceptualised and modelled as an isotropic pattern, that is, assuming that similarity decays with the same rate in all directions. Because climatic gradients are markedly anisotropic, that is, they have different strength in different directions, if species distributions were in equilibrium with climate, the decay of assemblage similarity should be anisotropic in the same direction as the climatic gradient, that is, faster turnover in the direction that maximises the climatic gradient. Thus, deviations from equilibrium between assemblage composition and climatic conditions would result in differences in anisotropy between distance-decay of similarity and climatic gradients. We assessed anisotropy in distance-decay patterns in marine plankton assemblages, terrestrial vertebrates and European beetles, using two procedures: (a) measuring the correlation between the residuals of a distance-decay model and the angle in which pairs of sites are separated and (b) computing two separate distance-decay models for each dataset, one using only pairwise cases that are separated on North-South direction and another one using pairwise cases separated on East-West direction. We also analysed whether the degree of anisotropy in distance-decay is related to dispersal ability (proportion of wingless species and body size) and ecological niche characteristics (main habitat and trophic position) by assessing these relationships among beetle taxonomic groups (n = 21). Anisotropy varied markedly across realms and biological groups. Despite climatic gradients being steeper in North-South direction than in East-West direction in all datasets, North-South distance-decays tended to be steeper than East-West distance-decays in plankton and most vertebrate assemblages, but flatter in European amphibians and most beetle groups. Anisotropy also markedly varied across beetle groups depending on their dispersal ability, as the proportion of wingless species explained 60% of the variance in the difference between North-South and East-West distance-decay slopes. Our results suggest that the degree of equilibrium decreases from marine to terrestrial realms, and is markedly different between vertebrates and beetles. This has profound implications on the expected ability of different groups to track their suitable climates, and thus on the impact of climate change on biodiversity.
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Affiliation(s)
- Andrés Baselga
- Department of Zoology, Genetics and Physical Anthropology, Universidade de Santiago de Compostela, Santiago de Compostela, Spain.,CRETUS, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Carola Gómez-Rodríguez
- CRETUS, Universidade de Santiago de Compostela, Santiago de Compostela, Spain.,Department of Functional Biology (Area of Ecology), Universidade de Santiago de Compostela, Santiago de Compostela, Spain
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9
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Chen D, Wang Y, Fu Y, Zhou H. Birefringence- and Optical Distortion-Free Isotropic Polymer Lens Assisted by Photonic Microspheres. ACS Appl Mater Interfaces 2020; 12:44172-44179. [PMID: 32853521 DOI: 10.1021/acsami.0c12479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Development of low-cost and light polymer optical devices to substitute for inorganic materials is a major trend. Traditional molten processing methods are direct and have been extensively applied in optical product manufacturing. However, the inevitable intrinsic birefringence and optical distortion due to polymer molecular chain anisotropy limit their application in high-end optical devices. Here, we report a novel thermocompression strategy for isotropic polymer lens fabrication, in which a cross-linked photonic crystal (PC) consisting of closely stacked polymer microspheres is used as a precursor and then heated and pressed under the rubbery state. A polymethyl methacrylate microsphere-based PC is used as a demonstration, and the obtained isotropic lenses exhibit superior performance compared to the traditional counterpart, which are birefringence-free (Δn < 1 × 10-5) and optical distortion-free and have excellent mechanical properties (hardness reaches 0.28 GPa), and the hidden mechanism is carefully studied. These properties enable the isotropic lens to be applied in precision optical components such as the lens of spectacles, microscope, telescope and endoscope, industrial camera, and astronaut helmet, and the proposed general method can extend to various polymers and provide new opportunities for the development of three-dimensional PCs.
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Affiliation(s)
- Dan Chen
- State Key Laboratory of Material Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yunming Wang
- State Key Laboratory of Material Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yue Fu
- State Key Laboratory of Material Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Huamin Zhou
- State Key Laboratory of Material Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074, China
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10
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von Weber A, Hooper DC, Jakob M, Valev VK, Kartouzian A, Heiz U. Circular Dichroism and Isotropy - Polarity Reversal of Ellipticity in Molecular Films of 1,1'-Bi-2-Naphtol. Chemphyschem 2018; 20:62-69. [PMID: 30444574 DOI: 10.1002/cphc.201800950] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 11/15/2018] [Indexed: 11/11/2022]
Abstract
We have studied the circular dichroism (CD), in the ultraviolet and visible regions, of the transparent, chiral molecule 1,1'-Bi-2-naphtol (BINOL) in 1.5 μm thick films. The initial transparent film shows an additional negative cotton effect in the CD compared to solution. With time under room temperature the film undergoes a structural phase transition. This goes hand in hand with a cotton effect at the low energy absorption band which inverts with opposite propagation direction of light through the film which is revealed as a polarity reversal of ellipticity (PRE). After completion of the phase transition the film exhibits circular differential scattering throughout the visible range which also shows PRE. The structure change was studied with Raman, microscopy under cross polarization conditions and nonlinear second-harmonic generation circular dichroism (SHG-CD). The superposition of the optical activity of individual molecules and isotropy effects makes an interpretation challenging. Yet overcoming this challenge by finding a suitable model structural information can be derived from CD measurements.
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Affiliation(s)
- Alexander von Weber
- Chair of Physical Chemistry, Chemistry Department & Catalysis Research Center, Technical University of Munich, Lichtenbergstr. 4, D-, 85748, Garching, Germany
| | - David C Hooper
- Centre for Photonics and Photonic Materials, Department of Physics, University of Bath, Claverton Down, Bath, BA2 7AY, United Kingdom.,Centre for Nanoscience and Nanotechnology, Department of Physics, University of Bath, Claverton Down, Bath, BA2 7AY, United Kingdom
| | - Matthias Jakob
- Chair of Physical Chemistry, Chemistry Department & Catalysis Research Center, Technical University of Munich, Lichtenbergstr. 4, D-, 85748, Garching, Germany
| | - Ventsislav K Valev
- Centre for Photonics and Photonic Materials, Department of Physics, University of Bath, Claverton Down, Bath, BA2 7AY, United Kingdom.,Centre for Nanoscience and Nanotechnology, Department of Physics, University of Bath, Claverton Down, Bath, BA2 7AY, United Kingdom
| | - Aras Kartouzian
- Chair of Physical Chemistry, Chemistry Department & Catalysis Research Center, Technical University of Munich, Lichtenbergstr. 4, D-, 85748, Garching, Germany
| | - Ueli Heiz
- Chair of Physical Chemistry, Chemistry Department & Catalysis Research Center, Technical University of Munich, Lichtenbergstr. 4, D-, 85748, Garching, Germany
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11
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Tancogne-Dejean T, Diamantopoulou M, Gorji MB, Bonatti C, Mohr D. 3D Plate-Lattices: An Emerging Class of Low-Density Metamaterial Exhibiting Optimal Isotropic Stiffness. Adv Mater 2018; 30:e1803334. [PMID: 30230617 DOI: 10.1002/adma.201803334] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 08/12/2018] [Indexed: 06/08/2023]
Abstract
In lightweight engineering, there is a constant quest for low-density materials featuring high mass-specific stiffness and strength. Additively-manufactured metamaterials are particularly promising candidates as the controlled introduction of porosity allows for tailoring their density while activating strengthening size-effects at the nano- and microstructural level. Here, plate-lattices are conceived by placing plates along the closest-packed planes of crystal structures. Based on theoretical analysis, a general design map is developed for elastically isotropic plate-lattices of cubic symmetry. In addition to validating the design map, detailed computational analysis reveals that there even exist plate-lattice compositions that provide nearly isotropic yield strength together with elastic isotropy. The most striking feature of plate-lattices is that their stiffness and yield strength are within a few percent of the theoretical limits for isotropic porous solids. This implies that the stiffness of isotropic plate-lattices is up to three times higher than that of the stiffest truss-lattices of equal mass. This stiffness advantage is also confirmed by experiments on truss- and plate-lattice specimens fabricated through direct laser writing. Due to their porous internal structure, the potential impact of the new metamaterials reported here goes beyond lightweight engineering, including applications for heat-exchange, thermal insulation, acoustics, and biomedical engineering.
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Affiliation(s)
- Thomas Tancogne-Dejean
- Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology (ETH), Tannenstrasse 3, Zurich, 8006, Switzerland
- Department of Mechanical Engineering, Massachusetts Institute of Technology (MIT), 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | - Marianna Diamantopoulou
- Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology (ETH), Tannenstrasse 3, Zurich, 8006, Switzerland
- Department of Mechanical Engineering, Massachusetts Institute of Technology (MIT), 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | - Maysam B Gorji
- Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology (ETH), Tannenstrasse 3, Zurich, 8006, Switzerland
- Department of Mechanical Engineering, Massachusetts Institute of Technology (MIT), 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | - Colin Bonatti
- Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology (ETH), Tannenstrasse 3, Zurich, 8006, Switzerland
- Department of Mechanical Engineering, Massachusetts Institute of Technology (MIT), 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | - Dirk Mohr
- Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology (ETH), Tannenstrasse 3, Zurich, 8006, Switzerland
- Department of Mechanical Engineering, Massachusetts Institute of Technology (MIT), 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
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12
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Shao H, Li J, Chen N, Shao G, Jiang J, Yang Y. Experimental Study on Bi-Axial Mechanical Properties of Warp-knitted Meshes with and without Initial Notches. Materials (Basel) 2018; 11:E1999. [PMID: 30332825 DOI: 10.3390/ma11101999] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 10/12/2018] [Accepted: 10/12/2018] [Indexed: 12/05/2022]
Abstract
Warp-knitted meshes have been widely used for structural reinforcement of rigid, semi-rigid, and flexible composite materials. In order to meet the performance requirements of different engineering applications, four typical warp-knitted meshes (rectangular, square, circular, and diamond) were designed and developed. The mechanical behaviors of these meshes under mono-axial and multi-axial tensile loads were compared. The influence of the initial notch length and orientation on the mechanical performance was also analyzed. The results showed that the biaxial tensile behavior of warp-knitted meshes tended to be more isotropic. The anisotropy level of the diamond warp-knitted mesh was the lowest (λ = 0.099), while the rectangular one was the highest (λ = 0.502). The notch on a significantly anisotropic mesh was propagated along the direction of larger modulus, while for a not remarkably anisotropic mesh, notch propagation was probably consistent with the initial notch orientation. The breaking strength of warp-knitted meshes with the same initial notch orientation decreased with the increase in notch length in both the wale and course directions. For warp-knitted meshes with the same initial notch length, the breaking strength in the wale direction was kept stable at different notch orientations, while that in the course direction decreased remarkably with notch orientation from 0° to 90°.
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Ur Rehman Z, Muhammad Z, Adetunji Moses O, Zhu W, Wu C, He Q, Habib M, Song L. Magnetic Isotropy/Anisotropy in Layered Metal Phosphorous Trichalcogenide MPS₃ (M = Mn, Fe)Single Crystals. Micromachines (Basel) 2018; 9:mi9060292. [PMID: 30424225 PMCID: PMC6187345 DOI: 10.3390/mi9060292] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Revised: 06/01/2018] [Accepted: 06/08/2018] [Indexed: 11/23/2022]
Abstract
Despite the fact that two-dimensional layered magnetic materials hold immense potential applications in the field of spintronic devices, tunable magnetism is still a challenge due to the lack of controllable synthesis. Herein, high-quality single crystals MPS3 (M= Mn, Fe) of millimeter size were synthesized through the chemical vapor transport method. After systemic structural characterizations, magnetic properties were studied on the bulk MPS3 layers through experiments, along with first principle theoretical calculations. The susceptibilities as well as the EPR results evidently revealed unique isotropic and anisotropic behavior in MnPS3 and FePS3 crystals, respectively. It is worth noting that both of these materials show antiferromagnetic states at measured temperatures. The estimated antiferromagnetic transition temperature is 78 K for bulk MnPS3 and 123 K for FePS3 crystals. The spin polarized density functional theory calculations confirmed that the band gap of the antiferromagnetic states could be generated owing to asymmetric response all over the energy range. The ferromagnetic state in MnPS3 and FePS3 is less stable as compared to the antiferromagnetic state, resulting in antiferromagnetic behavior. Additionally, frequency-dependent dielectric functions for parallel and perpendicular electric field component vectors, along with the absorption properties of MPS3, are thoroughly investigated.
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Affiliation(s)
- Zia Ur Rehman
- National Synchrotron Radiation Laboratory, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei 230029, China.
- Department of Applied Physics, University of Karachi, Karachi-75270, Pakistan.
| | - Zahir Muhammad
- National Synchrotron Radiation Laboratory, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei 230029, China.
| | - Oyawale Adetunji Moses
- National Synchrotron Radiation Laboratory, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei 230029, China.
| | - Wen Zhu
- National Synchrotron Radiation Laboratory, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei 230029, China.
| | - Chuanqiang Wu
- National Synchrotron Radiation Laboratory, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei 230029, China.
| | - Qun He
- National Synchrotron Radiation Laboratory, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei 230029, China.
| | - Muhammad Habib
- National Synchrotron Radiation Laboratory, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei 230029, China.
| | - Li Song
- National Synchrotron Radiation Laboratory, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei 230029, China.
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Fogaça DNL, da Silva WS, Rodrigues LB. Influence of compression parameters on mechanical behavior of mozzarella cheese. J Texture Stud 2017; 48:427-432. [PMID: 28967215 DOI: 10.1111/jtxs.12246] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 10/23/2016] [Accepted: 12/19/2016] [Indexed: 11/27/2022]
Abstract
Studies on the interaction between direction and degree of compression in the Texture Profile Analysis (TPA) of cheeses are limited. For this reason the present study aimed to evaluate the mechanical properties of Mozzarella cheese by TPA at different compression degrees (65, 75, and 85%) and directions (axes X, Y, and Z). Data obtained were compared in order to identify possible interaction between both factors. Compression direction did not affect any mechanical variable, or rather, the cheese had an isotropic behavior for TPA. Compression degree had a significant influence (p < 0.05) on TPA responses, excepting for chewiness TPA (N), which remained constant. Data from texture profile were adjusted to models to explain the mechanical behavior according to the compression degree used in the test. The isotropic behavior observed may be result of differences in production method of Mozzarella cheese especially on stretching of cheese mass. PRACTICAL APPLICATIONS Texture Profile Analysis (TPA) is a technique largely used to assess the mechanical properties of food, particularly cheese. The precise choice of the instrumental test configuration is essential for achieving results that represent the material analyzed. The method of manufacturing is another factor that may directly influence the mechanical properties of food. This can be seen, for instance, in stretched curd cheese, such as Mozzarella. Knowledge on such mechanical properties is highly relevant for food industries due to the mechanical resistance in piling, pressing, manufacture of packages, and food transport, or to melting features presented by the food at high temperatures in preparation of several foods, such as pizzas, snacks, sandwiches, and appetizers.
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Affiliation(s)
- Davi Novaes Ladeia Fogaça
- Federal Institute of Education Science and Technology of Bahia (IFBA), Rua Gileno de Sá, 271 - Recanto dos Pássaros, Barreiras, BA, CEP 47808-006, Brazil
| | - William Soares da Silva
- Materials and Environment Research Group, State University of Southwest Bahia, BR 415, km 04, s/n, CEP 45700-000, Itapetinga, BA, Brazil
| | - Luciano Brito Rodrigues
- Materials and Environment Research Group, State University of Southwest Bahia, BR 415, km 04, s/n, CEP 45700-000, Itapetinga, BA, Brazil
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Mandel K, Granath T, Wehner T, Rey M, Stracke W, Vogel N, Sextl G, Müller-Buschbaum K. Smart Optical Composite Materials: Dispersions of Metal-Organic Framework@Superparamagnetic Microrods for Switchable Isotropic-Anisotropic Optical Properties. ACS Nano 2017; 11:779-787. [PMID: 27943671 DOI: 10.1021/acsnano.6b07189] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A smart optical composite material with dynamic isotropic and anisotropic optical properties by combination of luminescence and high reflectivity was developed. This combination enables switching between luminescence and angle-dependent reflectivity by changing the applied wavelength of light. The composite is formed as anisotropic core/shell particles by coating superparamagnetic iron oxide-silica microrods with a layer of the luminescent metal-organic framework (MOF) 3∞[Eu2(BDC)3]·2DMF·2H2O (BDC2- = 1,4-benzenedicarboxylate). The composite particles can be rotated by an external magnet. Their anisotropic shape causes changes in the reflectivity and diffraction of light depending on the orientation of the composite particle. These rotation-dependent optical properties are complemented by an isotropic luminescence resulting from the MOF shell. If illuminated by UV light, the particles exhibit isotropic luminescence while the same sample shows anisotropic optical properties when illuminated with visible light. In addition to direct switching, the optical properties can be tailored continuously between isotropic red emission and anisotropic reflection of light if the illuminating light is tuned through fractions of both UV and visible light. The integration and control of light emission modes within a homogeneous particle dispersion marks a smart optical material, addressing fundamental directions for research on switchable multifunctional materials. The material can function as an optic compass or could be used as an optic shutter that can be switched by a magnetic field, e.g., for an intensity control for waveguides in the visible range.
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Affiliation(s)
- Karl Mandel
- Fraunhofer Institute for Silicate Research, ISC , Neunerplatz 2, D97082 Würzburg, Germany
- Chair of Chemical Technology of Materials Synthesis, Julius-Maximilians-University Würzburg , Röntgenring 11, D97070 Würzburg, Germany
| | - Tim Granath
- Chair of Chemical Technology of Materials Synthesis, Julius-Maximilians-University Würzburg , Röntgenring 11, D97070 Würzburg, Germany
| | - Tobias Wehner
- Institute of Inorganic Chemistry, Julius-Maximilians-University Würzburg , Am Hubland, 97074 Würzburg, Germany
| | | | - Werner Stracke
- Fraunhofer Institute for Silicate Research, ISC , Neunerplatz 2, D97082 Würzburg, Germany
| | | | - Gerhard Sextl
- Fraunhofer Institute for Silicate Research, ISC , Neunerplatz 2, D97082 Würzburg, Germany
- Chair of Chemical Technology of Materials Synthesis, Julius-Maximilians-University Würzburg , Röntgenring 11, D97070 Würzburg, Germany
| | - Klaus Müller-Buschbaum
- Institute of Inorganic Chemistry, Julius-Maximilians-University Würzburg , Am Hubland, 97074 Würzburg, Germany
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Sandu G, Brassart L, Gohy JF, Pardoen T, Melinte S, Vlad A. Surface coating mediated swelling and fracture of silicon nanowires during lithiation. ACS Nano 2014; 8:9427-9436. [PMID: 25133525 DOI: 10.1021/nn503564r] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Surface passivation of silicon anodes is an appealing design strategy for the development of reliable, high-capacity lithium-ion batteries. However, the structural stability of the coating layer and its influence on the lithiation process remain largely unclear. Herein, we show that surface coating mediates the swelling dynamics and the fracture pattern during initial lithiation of crystalline silicon nanopillars. We choose conformally nickel coated silicon architectures as a model system. Experimental findings are interpreted based on a chemomechanical model. Markedly different swelling and fracture regimes have been identified, depending on the coating thickness and silicon nanopillar diameter. Nanopillars with relatively thin coating display anisotropic swelling similar to pristine nanopillars, but with different preferred fracture sites. As the coating thickness increases, the mechanisms become isotropic, with one randomly oriented longitudinal crack that unzips the core-shell structure. The morphology of cracked pillars resembles that of a thin-film electrode on a substrate, which is more amenable to cyclic lithiation without fracture. The knowledge provided here helps clarify the cycling results of coated nanosilicon electrodes and further suggests design rules for better performance electrodes through proper control of the lithiation and fracture.
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Affiliation(s)
- Georgiana Sandu
- Institute of Information and Communication Technologies, Electronics and Applied Mathematics, ‡Institute of Mechanics, Materials, and Civil Engineering, and §Institute of Condensed Matter and Nanosciences, Université Catholique de Louvain , 1348 Louvain-la-Neuve, Belgium
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Djomehri S, Zeid H, Yavari A, Mobed-Miremadi M, Youssefi K, Liao-Chan S. Simulation and verification of macroscopic isotropy of hollow alginate-based microfibers. Artif Cells Nanomed Biotechnol 2014; 43:390-7. [PMID: 24684489 DOI: 10.3109/21691401.2014.897629] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
A simulation of tensile strength of various alginate-based hollow microfibers using FEA analysis has been conducted with the hypothesis of macroscopic isotropy and linear elastic-plastic behavior. Results of student t-tests indicated that there was no significant difference between the experimental and simulated tensile strengths (p = 0.37, α = 0.05), while there was a significant reduction in elasticity as a result of chitosan coating (p = 0.024, α = 0.05). The hypothesis of macroscopic isotropy was verified by highly correlated (R(2) ≥ 0.92) theoretical and experimental elongation at break measurements, findings that could be extended to the failure analysis of alginate microfibers used in regenerative medicine.
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Affiliation(s)
- Sabra Djomehri
- a Biomedical, Chemical and Materials Engineering, San Jose State University , San Jose , CA , USA
| | - Hanaa Zeid
- a Biomedical, Chemical and Materials Engineering, San Jose State University , San Jose , CA , USA
| | - Alireza Yavari
- a Biomedical, Chemical and Materials Engineering, San Jose State University , San Jose , CA , USA
| | | | - Kenneth Youssefi
- c Mechanical and Aerospace Engineering, San Jose State University , San Jose , CA , USA
| | - Sindy Liao-Chan
- d Department of Chemistry and Biochemistry , San Francisco State University , San Francisco , CA , USA
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