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971.
Hansohl Cho James C. Weaver Elmar Pöselt Pieter J. in't Veld Mary C. Boyce Gregory C. Rutledge 《Advanced functional materials》2016,26(38):6938-6949
This work demonstrates how the geometric and topological characteristics of substructures within heterogeneous materials can be employed to tailor the mechanical responses of soft crystals under large strains. The large deformation mechanical behaviors of elastomeric composites possessing long‐range crystalline order are examined using both experiments on 3D‐printed prototype materials and precisely matched numerical simulations. The deformation mechanisms at small and large strains are elucidated for six sets of morphologies: dispersed particles on each of the simple cubic, body‐centered cubic or face‐centered cubic lattices, and their bi‐continuous counterparts. Comparison of results for the six types of morphologies reveals that the topological connectivity of dissimilar domains is of critical importance for tailoring the macroscopic mechanical properties and the mechanical anisotropy. 相似文献
972.
Architected materials typically maintain their properties throughout their lifetime. However, there is growing interest in the design and fabrication of responsive materials with properties that adapt to their environment. Toward this goal, a versatile framework to realize thermally programmable lattice architectures capable of exhibiting a broader range of mechanical responses is reported. The lattices are composed of two polymeric materials with disparate glass transition temperatures, which are deterministically arranged via 3D printing. By tailoring the local composition and structure, architected lattices with tunable stiffness, Poisson's ratio, and deformation modes controlled through changes in the thermal environment are generated. The platform yields lightweight polymer lattices with programmable composition, architecture, and mechanical response. 相似文献
973.
974.
Fan Wang Qinchuan Li Jong-Oh Park Shaohui Zheng Eunpyo Choi 《Advanced functional materials》2021,31(13):2007749
The development of ultralow voltage high-performance bioartificial muscles with large bending strain, fast response time, and excellent actuation durability is highly desirable for promising applications such as soft robotics, active biomedical devices, flexible haptic displays, and wearable electronics. Herein, a novel high-performance low-priced bioartificial muscle based on functional carboxylated bacterial cellulose (FCBC) and polypyrrole (PPy) nanoparticles is reported, exhibiting a large bending strain of 0.93%, long actuated bending durability (96% retention for 5 h) under an ultralow harmonic input of 0.5 V, broad frequency bandwidth up to 10 Hz, fast response time (≈4 s) in DC responses, high energy density (6.81 KJ m−3), and high power density (5.11 KW m−3), all of which mainly stem from its high surface area and porosity, large specific capacitance, tuned mechanical properties, and strong ionic interactions of cations and anions in ionic liquid with FCBC and PPy nanoparticles. More importantly, bioinspired applications such as the grapple robot, bionic medical stent, bionic flower, and wings-vibrating have been realized. These successful demonstrations offer a viable means for developing high-performance bioartificial muscles for next-generation soft bioelectronics including bioinspired robotics, biomedical microdevices, and wearable electronics. 相似文献
975.
976.
Research in the field of liquid crystalline polymers has recently witnessed the introduction of liquid crystalline hydrogels. Here, we report the synthesis and characterization of a new liquid crystalline network featuring elastomeric softness, water‐swelling and shape memory characteristics. By comparing with a nonmesogenic network prepared using the same procedure, we reveal structure–property relationships of the liquid crystalline and crystalline polymer networks. Wide angle and small angle X‐ray scattering studies were used to examine the liquid crystalline ordering in both dry and hydrated states. Such ordering was found to be related to the observed shape memory and actuation (two‐way shape memory) properties and these phenomena are highlighted with demonstrations of shape change in response to heat and water stimuli. This study provides insight into the mechanisms affecting the shape evolution of water activated anisotropic liquid crystalline hydrogels and enables the future design of materials or devices for a variety of applications such as biomaterials interacting with body fluids in a hydrated state. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 38–52 相似文献
977.
Andrew R. Hirst Dr. Juan F. Miravet Dr. Beatriu Escuder Dr. Laurence Noirez Dr. Valeria Castelletto Ian W. Hamley Prof. Dr. David K. Smith Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(2):372-379
Two‐component systems capable of self‐assembling into soft gel‐phase materials are of considerable interest due to their tunability and versatility. This paper investigates two‐component gels based on a combination of a L ‐lysine‐based dendron and a rigid diamine spacer (1,4‐diaminobenzene or 1,4‐diaminocyclohexane). The networked gelator was investigated using thermal measurements, circular dichroism, NMR spectroscopy and small angle neutron scattering (SANS) giving insight into the macroscopic properties, nanostructure and molecular‐scale organisation. Surprisingly, all of these techniques confirmed that irrespective of the molar ratio of the components employed, the “solid‐like” gel network always consisted of a 1:1 mixture of dendron/diamine. Additionally, the gel network was able to tolerate a significant excess of diamine in the “liquid‐like” phase before being disrupted. In the light of this observation, we investigated the ability of the gel network structure to evolve from mixtures of different aromatic diamines present in excess. We found that these two‐component gels assembled in a component‐selective manner, with the dendron preferentially recognising 1,4‐diaminobenzene (>70 %), when similar competitor diamines (1,2‐ and 1,3‐diaminobenzene) are present. Furthermore, NMR relaxation measurements demonstrated that the gel based on 1,4‐diaminobenzene was better able to form a selective ternary complex with pyrene than the gel based on 1,4‐diaminocyclohexane, indicative of controlled and selective π–π interactions within a three‐component assembly. As such, the results in this paper demonstrate how component selection processes in two‐component gel systems can control hierarchical self‐assembly. 相似文献
978.
Soft error is becoming increasingly important in the era of sub-100 nanometer very large scale integrated (VLSI) circuits. This article focuses on the impact of soft error on an OpenRisc 1200 CPU core. A C++ programming language based soft error analysis tool, with the name of SERSim, is created to perform a detailed exploration of this impact. The estimation error of SERSim ranges from 0.1% to 4.5%. With the help of SERSim, we find out that almost all the glitch widths are narrower than 200 ps in a 45 nm OpenRisc 1200 microprocessor circuit. This result is important for soft error rate reduction of VLSI circuits. The outputs of the multiplier of the OpenRisc 1200 microprocessor are found to be the most troublesome. Those outputs, which represent only 3% of the circuit outputs, produce more than half of the circuit bit error rate. A significant impact of performance requirements on circuit vulnerability to soft error is observed in our experiment. The difference helps us to analyse the estimation error of high-level soft error models. 相似文献
979.
基于近似扁长椭球波函数的超宽带脉冲设计 总被引:15,自引:0,他引:15
频谱共存及兼容是超宽带(UWB)无线通信系统必须考虑的重要问题。为了避免超宽带系统对现有窄带无线系统的干扰,一个有效的方法是设计合适的脉冲波形。在建立超宽带脉冲设计算法的基础上,分析了扁长椭球波函数(PSWF)的近似解,提出了用近似扁长椭球波函数(APSWF)进行脉冲波形设计的方法。近似扁长椭球波函数具有简单明确的数学表达式,仿真表明用其设计的脉冲功率谱符合FCC频率掩模的约束要求。当频率掩模发生变化时,可方便地调整参数以产生新的脉冲。 相似文献
980.