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51.
Nina Qian Hari Krishna Bisoyi Meng Wang Shuai Huang Zhongcheng Liu Xu-Man Chen Jun Hu Hong Yang Quan Li 《Advanced functional materials》2023,33(16):2214205
In recent years, although light-driven soft actuators have attracted intense scientific attention and achieved remarkable progress, the design and construction of an intelligent robotic system with maneuverability, self-adaptability, untethered control, and greater freedom of action, in particular the omnidirectional motion capability on a plane, remains challenging. Herein, four types of photo-thermal fillers and an unprecedented twist-bend actuation mode is introduced into a liquid crystal elastomer-based soft robot. The obtained twist-bend crawling robot not only exhibits in situ rotation, four-way turning, and four-way linear motion under light irradiation with four wavelength bands (520, 655, 808, and 980 nm), but also demonstrates the ability to avoid obstacles in complex geographical environments. This work may bring a new perspective for fabrication and development of soft robots that can adapt to dynamic and complex environmental conditions. 相似文献
52.
This article proposes a new switched adaptive control design for uncertain switched systems with composite (time-driven and state-dependent) switching and shows its applicability in switched impedance control. A composite switched adaptive control design, consisting of the direct switched adaptive control and the indirect switched adaptive control counterpart, is developed to improve the control performance. Specifically, a new stability condition for composite switching is proposed by making use of differential matrix equations and Sylvester matrix equations, which are a generalization of Lyapunov matrix equations. The design results in a time-varying multiple Lyapunov function that is decreasing at the switching instants. From the theoretical point of view, the relevance of this work is the construction of the adaptive laws that guarantee asymptotic tracking error and asymptotic estimation for the direct and indirect switched adaptive control loops, respectively. From the practical point of view, the relevance of this work is validated in a new switched impedance control for the robot interaction with uncertain and discontinuous environments. 相似文献
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Computational Economics - The study aims to analyze and forecast Internet financial risks based on the model based on deep learning and the Back Propagation Neural Network (BPNN). First, the theory... 相似文献
56.
Shiwei?Zhao T.?Matthew?EvansEmail authorView authors OrcID profile Xiaowen?Zhou Shuai?Zhou 《Granular Matter》2017,19(1):11
Temperature change, as a common kind of internal perturbation performed on granular materials, has a significant effect on the bulk properties of granular materials. However, few studies on thermally-induced shakedown under a long-term thermal cycling were reported. In this work, the discrete element method was used to give insight into the thermally-induced shakedown on the fabric and stress states within non-cohesive, frictional granular assemblies. Assemblies were submitted to thermal cycling at a stationary boundary condition after experiencing a one-dimensional compression. Evolution of coordination number, entropy and anisotropy was investigated as well as boundary forces and contact forces. At the same time, effects of the heating rate, the initial vertical load and the magnitude of temperature change were examined. It demonstrates that thermal cycling induces a significant force relaxation within granular materials, while the corresponding granular fabric has a small change. In addition, the entropy and anisotropy decreases with thermal cycling. Moreover, the initial vertical load can constrain the development of thermally-induced fabric change, thereby limiting force relaxation to some degree. Both high heating rate and larger magnitudes of temperature change contribute to more significant force relaxation. However, they cause smaller fabric changes even though they provide larger perturbations. 相似文献
57.
Carbon nanosheets with a tunable mesopore size,large pore volume,and good electronic conductivity are synthesized via a solution-chemistry approach.In this synthesis,diaminohexane and graphene oxide (GO) are used as the structural directing agents,and a silica colloid is used as a mesopores template.Diaminohexane plays a crucial role in bridging silica colloid particles and GO,as well as initiating the polymerization of benzoxazine on the surfaces of both the GO and silica,resulting in the formation of a hybrid nanosheet polymer.The carbon nanosheets have graphene embedded in them and have several spherical mesopores with a pore volume up to 3.5 cm3·g-1 on their surfaces.These nuerous accessible mesopores in the carbon layers can act as reservoirs to host a high loading of active charge-storage materials with good dispersion and a uniform particle size.Compared with active materials with wide particle-size distributions,the unique proposed configuration with confined and uniform particles exhibits superior electrochemical performance during lithiation and delithiation,especially during long cycles and at high rates. 相似文献
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以1-甲基咪唑、1,4-丁烷磺内酯和浓硫酸为原料,用乙醚洗涤合成了1-甲基-3-(4-硫酸基丁基)咪唑硫酸盐(4-BMIM)缓蚀剂。采用动电位极化和交流阻抗技术研究了4-BMIM在5%HCl溶液中对铜的缓蚀性能及作用机理。实验结果表明:缓蚀效率随着缓蚀剂浓度的增加先增大后降低,当浓度为0.03mol/L时,缓蚀效率最高;同一浓度下,随着温度的升高缓蚀效率降低。动电位极化表明咪唑离子的加入对铜的阴、阳极腐蚀过程均有抑制作用,是混合型缓蚀剂。热力学计算结果表明咪唑离子液体吸附在铜表面,其吸附机制为自发进行的物理吸附,并且在铜/溶液界面的吸附遵循Langmuir吸附等温式。 相似文献
60.
Monitoring the Dynamic Process of Formation of Plasmonic Molecular Junctions during Single Nanoparticle Collisions 下载免费PDF全文
Jing Guo Jie Pan Shuai Chang Xuewen Wang Na Kong Wenrong Yang Jin He 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(15)
The capability to study the dynamic formation of plasmonic molecular junction is of fundamental importance, and it will provide new insights into molecular electronics/plasmonics, single‐entity electrochemistry, and nanooptoelectronics. Here, a facile method to form plasmonic molecular junctions is reported by utilizing single gold nanoparticle (NP) collision events at a highly curved gold nanoelectrode modified with a self‐assembled monolayer. By using time‐resolved electrochemical current measurement and surface‐enhanced Raman scattering spectroscopy, the current changes and the evolution of interfacial chemical bonding are successfully observed in the newly formed molecular tunnel junctions during and after the gold NP “hit‐n‐stay” and “hit‐n‐run” collision events. The results lead to an in‐depth understanding of the single NP motion and the associated molecular level changes during the formation of the plasmonic molecular junctions in a single NP collision event. This method also provides a new platform to study molecular changes at the single molecule level during electron transport in a dynamic molecular tunnel junction. 相似文献