Search

Your search keyword '"Zhang, Yingjiu"' showing total 372 results
Start Over Author "Zhang, Yingjiu"
372 results on '"Zhang, Yingjiu"'

25. High‐Strength, Antiswelling Directional Layered PVA/MXene Hydrogel for Wearable Devices and Underwater Sensing.

Author

Zhang, Shipeng, Guo, Fengmei, Gao, Xue, Yang, Mengdan, Huang, Xinguang, Zhang, Ding, Li, Xinjian, Zhang, Yingjiu, Shang, Yuanyuan, and Cao, Anyuan

Subjects
TISSUE engineering, HYDROGELS, TENSILE strength, WEARABLE technology, BIOCOMPATIBILITY
Abstract

Hydrogel sensors are widely utilized in soft robotics and tissue engineering due to their excellent mechanical properties and biocompatibility. However, in high‐water environments, traditional hydrogels can experience significant swelling, leading to decreased mechanical and electrical performance, potentially losing shape, and sensing capabilities. This study addresses these challenges by leveraging the Hofmeister effect, coupled with directional freezing and salting‐out techniques, to develop a layered, high‐strength, tough, and antiswelling PVA/MXene hydrogel. In particular, the salting‐out process enhances the self‐entanglement of PVA, resulting in an S‐PM hydrogel with a tensile strength of up to 2.87 MPa. Furthermore, the S‐PM hydrogel retains its structure and strength after 7 d of swelling, with only a 6% change in resistance. Importantly, its sensing performance is improved postswelling, a capability rarely achievable in traditional hydrogels. Moreover, the S‐PM hydrogel demonstrates faster response times and more stable resistance change rates in underwater tests, making it crucial for long‐term continuous monitoring in challenging aquatic environments, ensuring sustained operation and monitoring. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

26. Wet‐Spinning Carbon Nanotube/Shape Memory Polymer Composite Fibers with High Actuation Stress and Predesigned Shape Change.

Author

Li, Meng, Chen, Kun, Zhang, Ding, Ye, Ziming, Yang, Zifan, Wang, Qi, Jiang, Zhifan, Zhang, Yingjiu, Shang, Yuanyuan, and Cao, Anyuan

Subjects
MANUFACTURING processes, CARBON composites, ELECTRIC stimulation, NANOSTRUCTURED materials, MOLECULAR orientation, FIBROUS composites, SHAPE memory polymers
Abstract

Actuators based on shape memory polymers and composites incorporating nanomaterial additives have been extensively studied; achieving both high output stress and precise shape change by low‐cost, scalable methods is a long‐term‐desired yet challenging task. Here, conventional polymers (polyurea) and carbon nanotube (CNT) fillers are combined to fabricate reinforced composite fibers with exceptional actuation performance, by a wet‐spinning method amenable for continuous production. It is found that a thermal‐induced shrinkage step could obtain densified strong fibers, and the presence of CNTs effectively promotes the tensile orientation of polymer molecular chains, leading to much improved mechanical properties. Consequently, the CNT/ polyurea composite fibers exhibit stresses as high as 33 MPa within 0.36 s during thermal actuation, and stresses up to 22 MPa upon electrical stimulation enabled by the built‐in conductive CNT networks. Utilizing the flexible thin fibers, various shape change behavior are also demonstrated including the conversion between different structures/curvatures, and recovery of predefined simple patterns. This high‐performance composite fibers, capable of both thermal and electrical actuation and produced by low‐cost materials and fabrication process, may find many potential applications in wearable devices, robotics, and biomedical areas. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

44. Enhanced thermoelectric properties of Bi2Sr2Co2Oy ceramics by dispersing B2O3 additive.

Author

Xu, Yingying, Xia, Siyi, Zhang, Yingjiu, Song, Hongzhang, Liu, Shaohui, and Hao, Haoshan

Subjects
PHONON scattering, THERMAL conductivity, CHARGE carrier mobility, HETEROJUNCTIONS, ADDITIVES
Abstract

In this study, ceramic samples of Bi2Sr2Co2Oy + v wt% B2O3 (v = 0.0, 0.1, 0.2, 0.3, 0.4) were synthesized using the solid state reaction method, and the influence of B2O3 additive on their microstructure and thermoelectric properties were investigated. On one hand, the B2O3 additive acted as a sintering aid, enhancing carrier mobility. On the other hand, B2O3 dispersion served as a nano-second-phase, increasing hetero-interfaces and strengthen phonon scattering, thereby effectively suppressing lattice thermal conductivity. By dual optimization of both electric and thermal transport performance, the Bi2Sr2Co2Oy + 0.3 wt% B2O3 sample achieved a high ZT value (thermoelectric figure of merit) of 0.31 at 923 K, which was improved by approximately 33% compared with the pristine Bi2Sr2Co2Oy sample. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

49. Tailoring Ti3C2TxMXene Flake Sizes for Modified Electrochemical Performance: A Top-down Approach

Author

Fan, Yuchao, Mei, Xu, Ye, Li, Tian, Qingyong, Zhang, Renqi, Zhang, Yingjiu, and Li, Xinjian

Abstract

Introduction: Two-dimensional (2D) materials, such as MXene (Ti3C2Tx), have garnered extensive attention in recent years due to their exceptional performance across various domains. The flake size of Ti3C2Txnotably influences its specific surface area, a pivotal factor in interfacial interactions within electrochemistry.Method: Presently, modifying the flake size of bulk Ti3C2Txtypically involves complex and costly processes, like ultrasonic treatment and isolation. Leveraging the specific preparation principle of MXenes, which involves etching the A layers in precursor MAX phases, a topdown strategy for producing Ti3C2Txflakes of desired sizes, has been proposed in this work. In this approach, precursor Ti3AlC2 particles undergo ball-milling to adjust their size.Result: Through this innovative strategy, dispersions of Ti3C2Txflakes with varying average lateral sizes are generated, enabling an investigation into the impact of lateral size on the electrochemical properties of Ti3C2Txflakes. By controlling the ball milling time for Ti3AlC2powders, the resulting average sizes of Ti3C2Tx(0, 2, 4) are 6.34 µm, 2.16 µm, and 0.96 µm, respectively. Particularly, the Ti3C2Tx(2) electrode, composed of 2.16 µm sheets, demonstrates remarkable performance metrics. It exhibits a high areal capacitance of 845.0 mF/cm2at a scan rate of 5 mV/s, along with a gravimetric capacitance of 244.0 F/g at a current density of 1 A/g.Conclusion: This study presents a facile method to enable mass production of Ti3C2Txwith sheets of varying sizes, addressing both small and large dimensions.

Published
2024
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results