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36 results on '"Cai, Shengying"'

12. Wet-spinning assembly of nitrogen-doped graphene film for stable graphene-polyaniline supercapacitor electrodes with high mass loading

Author

Chu, Xingyuan, Huang, Tieqi, Hu, Yueqi, Dong, Ruilin, Luo, Jingyang, Cai, Shengying, Gao, Weiwei, Xu, Zhen, and Gao, Chao

Abstract

Graphene-polyaniline (GP) composites are promising electrode materials for supercapacitors but possessing unsatisfied stability, especially under high mass loading, due to the low ion transmission efficiency and serious pulverization effect. To address this issue, we propose a scalable method to achieve highly wettable GP electrodes, showing excellent stability. In addition, our results demonstrate that the performance of electrodes is nearly independent of the mass loading, indicating the great potential of such GP electrodes for practical devices. We attribute the remarkable performance of GP to the delicate precursor of nitrogen doped graphene film assembled by wet-spinning technology. This report provides a strategy to promote the ion penetrating efficiency across the electrodes and deter the pulverization effect, aiming at the practical GP supercapacitor electrodes of high mass loading. 石墨烯-聚苯胺(GP)复合材料是一种有前途的超级电容器电极材料, 但其稳定性较差, 尤其在负载量高的情况下. 低离子传输效率和严重的粉碎效应是导致这一结果的主要原因. 为了解决这个问题, 我们提出了一种可规模化制备高度可润湿GP电极的方法, 该电极显示出优异的稳定性. 此外, 研究结果表明电极的性能几乎与负载量无关, 因此这种GP电极在实际生产中具有巨大潜力. 通过湿纺技术组装的氮掺杂石墨烯薄膜前驱体使得这种电极材料表现出卓越性能. 这种提高电极间离子渗透效率并阻止粉碎效应的方法, 旨在制备实用型高负载量的GP超级电容器电极.

Published
2024
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15. High-Precision and Reliable Thermal Conductivity Measurement for Graphene Films Based on an Improved Steady-State Electric Heating Method

Author

Lu, Jiahao, Ming, Xin, Liu, Yingjun, Hao, Yuanyuan, Zhang, Peijuan, Shi, Songhan, Mao, Yi, Yu, Yue, Cai, Shengying, Xu, Zhen, and Gao, Chao

Abstract

The graphene film with high thermal conductivity has garnered considerable attention in recent years as an ideal material for dissipating heat in high-power electronic devices. Thermal conductivity is a crucial parameter for evaluating its fundamental performance. High-precision measurement holds significant importance for understanding its basic properties, fabrication optimization, and industrial applications. However, it is difficult to simultaneously achieve efficient, accurate, and reliable measurements with existing commercial thermal conductivity testing methods. The development of a convenient, high-precision, and reliable measurement approach remains a great challenge. Here, we introduce a thermal conductivity testing methodology with superior accuracy and excellent efficiency based on an improved steady-state electric heating method, refined through the optimization of heat transfer principles, experimental operation, and data analysis, supported by finite element simulation. The accuracy of measurements is affected by four factors: heat loss calibration, sample size, device design, and data treatment. The experimental results show that the heat loss caused by heat radiation and heat convection affects the temperature distribution and the measurements of the sample, which should be strictly controlled by sample size and temperature rise. Reasonable screening and preprocessing of data are also necessary to improve measurement accuracy. Through the comparative analysis of the temperature distribution and thermal conductivity measurements of samples under different conditions, we propose feasible operational guidance and a standardized testing protocol to minimize measurement error. The measurement error is less than 3.0%, and uncertainty is reduced to 0.5%. Simulation results confirm that the response time of this method is down to milliseconds, correlating well with the experiment, which can effectively improve test efficiency. Considering the combined merits of high accuracy, repeatability, and fast response, the improved steady-state electric heating method offers useful guidance for the accurate evaluation of the thermal conductivity of materials and crucial technical support for research and application in thermal management.

Published
2025
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33. Amphiphilic Hyperbranched Polymers: Synthesis and Host-Guest Supermolecular Coloring Application.

Author

Zheng, Yaochen, Tang, Aijin, Weng, Zhulin, Cai, Shengying, Jin, Yu, Gao, Zhengguo, and Gao, Chao

Subjects
POLYMER research, AMPHIPHILES, CHEMICAL synthesis, POLYMERIZATION research, SUPRAMOLECULAR chemistry
Abstract

A novel kind of amphiphilic hyperbranched poly(propargyl quaternary ammomium methacrylate)- co-polymethyl methacrylate (HPPrAM- co-PMMA) is facilely synthesized via a combination of self-condensing vinyl polymerization (SCVP), reversible addition-fragmentation chain transfer (RAFT) polymerization, and a highly efficient Menschutkin reaction. With water soluble quaternary ammonium salt moieties and hydrophobic PMMA segments, the amphiphilic HPPrAM- co-PMMA is further employed as the host molecule for anionic dye supermolecular encapsulation. Due to the strong electrostatic interaction and large polar difference between the HPPrAM and PMMA moieties, the AHP exhibits a high loading capability of water soluble dyes ( Cdyes) (such as rose bengal, methyl orange, and fluorescein sodium). Furthermore, the AHP-dye complex is used as a coloring additive for common polymers, such as styrene- block-butadiene- block-styrene copolymer (SBS) and poly(methyl methacrylate) (PMMA). A sample colored with the AHP-dye complex shows good dye dispersion, uniformity, and coloring stability. [ABSTRACT FROM AUTHOR]

Published
2016
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34. Facile Fabrication of Palladium Nanoparticles Immobilized on the Water-Stable Polyvinyl Alcohol/Polyehyleneimine Nanofibers Via In-Situ Reduction and Their High Electrochemical Activity.

Author

Wang, Pan, Zhang, Ming, Cai, YingTing, Cai, ShengYing, Du, MingLiang, Zhu, Han, Bao, ShiYong, and Xie, Qin

Subjects
PALLADIUM, NANOPARTICLES, POLYVINYL alcohol, NANOFIBERS, ELECTROCHEMISTRY
Abstract

A facile strategy for the fabrication of electrochemical biosensors by immobilizing well-dispersed palladium nanoparticles (PdNPs) on the water-stable polyvinyl alcohol/polyethyleneimine (PVA/PEI) nanofibers through the combination of electrospinning technique and the process ofin-situreduction has been demonstrated. The synthesized PdNPs/(PVA/PEI) nanocomposites were characterized by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The experimental results confirmed that the PdNPs immobilized on the electrospun PVA/PEI nanofibers with an average diameter of 3.4 nm were well-dispersed, which could be ascribed to the complexation between Pd(II) and the free amine groups of PEI. Further investigations suggested that the PdNPs/(PVA/PEI) nanocomposites with well-separated PdNPs and large surface area exhibited high performance as electrochemical biosensors to detect hydrogen peroxide (H2O2). [ABSTRACT FROM AUTHOR]

Published
2014
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36. Atomically Thin TaSe 2 Film as a High-Performance Substrate for Surface-Enhanced Raman Scattering.

Author

Ge Y, Wang F, Yang Y, Xu Y, Ye Y, Cai Y, Zhang Q, Cai S, Jiang D, Liu X, Liedberg B, Mao J, and Wang Y

Subjects
Bilirubin, Humans, Infant, Newborn, Silver chemistry, Metal Nanoparticles chemistry, Spectrum Analysis, Raman
Abstract

An atomically thin TaSe 2 sample, approximately containing two to three layers of TaSe 2 nanosheets with a diameter of 2.5 cm is prepared here for the first time and applied on the detection of various Raman-active molecules. It achieves a limit of detection of 10 -10  m for rhodamine 6G molecules. The excellent surface-enhanced Raman scattering (SERS) performance and underlying mechanism of TaSe 2 are revealed using spectrum analysis and density functional theory. The large adsorption energy and the abundance of filled electrons close to the Fermi level are found to play important roles in the chemical enhancement mechanism. Moreover, the TaSe 2 film enables highly sensitive detection of bilirubin in serum and urine samples, highlighting the potential of using 2D SERS substrates for applications in clinical diagnosis, for example, in the diagnosis of jaundice caused by excess bilirubin in newborn children., (© 2022 Wiley-VCH GmbH.)

Published
2022
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