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416 results on '"Wang, Kaiping"'

59. Conductive Conjugated Polymer for Flexible Electronics and Energy Storage

Author

wang, kaiping

Subjects
Materials Science, Energy, Conductive Polymer, Energy Storage, Flexible Electronics, Supercapacitor
Abstract

Conductive polymer is studied intensively in the last several decades. Due to its eminent properties, such as high electronic and ionic conductivity, flexible, stretchable, easy to process and so on, it is widely employed in the flexible electronics and energy storage devices.The multichannel flexible concentric – ring dry electrodes for electrophysiological recordings is developed. Conductive polymer poly(3,4-ethylenedioxythiophene) polystyrene sulfonate is utilized as the interface layer to lower the impedance and noise level. The concentric ring geometry enables Laplacian filtering to pinpoint the bioelectric potential source with spatial resolution determined by the ring distance.Build on this flexible electrode, we develope a platform to systematically study the effects of electrical stimulation upon the inflammation phase and the activation of signaling mediators. With the help of flexible electrode, this platform enable studies of in-vivo immune cell response of electrical stimulation in the molecular level. We find that low frequency electrical stimulation increase phosphorylation of Erk proteins in recruited leukocytes, identifying a signaling pathway that is activated during the healing process.Besides the application of conductive polymer in flexible electrode, we demonstrate a new type of faradaic electrode material comprised of a very narrow bandgap donor−acceptor conductive polymer in electrochemical supercapacitor. Due to its charge delocalization in the reduced state, the anode retain 90% of its initial capacitance after 2000 full charge – discharge cycles, which exceeds other n-dopable organic materials and is practical for commercial use. Redox cycling processes are monitored in situ by optoelectronic measurements due to the polymer’s electrochromism to separate chemical versus physical degradation mechanisms. Asymmetric supercapacitors is fabricated using this n-dopable polymer in combination with p-type PEDOT:PSS operate within a 3 V potential window, with a best-in-class energy density of 30.4 Wh/kg at a 1 A/g discharge rate, a power density of 14.4 kW/kg at a 10 A/g discharge rate.During the electrochemical supercapacitor development, we find that self-discharge of supercapacitor is one of the bottleneck for its widely application. To solve this issue, we demonstrate a separator with sulfonate ion-exchange resin which can suppress self-discharge by trapping impurities in the electrolyte. Temperature-dependent characteristics are analyzed to identify that the reduction of impurity concentration and diffusion is key to improve potential retention. It is demonstrated to work with radio-frequency energy harvesting circuits and shows the potential to serve as an energy reservoir for wireless electronic applications.

Published
2020

63. Structural characterisation and structure-antioxidant activity relationship of polysaccharides from Dendrobium catenatum Lindl.

Author

Wang, Hongjing, Zheng, Ziming, Wu, Zhijing, Song, Mengzi, Yu, Zhang, and Wang, Kaiping

Subjects
POLYSACCHARIDES, DENDROBIUM, ANALYTICAL chemistry, CHINESE medicine, HYDROXYL group
Abstract

Dendrobium catenatum Lindl. has been long used in China as a functional food and traditional Chinese medicine and polysaccharides from Dendrobium catenatum Lindl. (DOP) exhibited extensive bioactivities. However, studies on the structure-activity relationship of DOP are rarely reported. Here, two polysaccharides named DOP-1 and DOP-2 were obtained, which differed in the ratio of monosaccharide composition and molecular weight. Structural characteristics were elucidated by spectral and chemical analysis. The main structures of DOPs were the linkage of β-(1→4)-D-Manp, with some attached 2-O- or 3-O-acetylated groups. Additionally, the DPPH, hydroxyl and superoxide radicals scavenging assays of DOP-1 and DOP-2 showed that DOP-2 exhibited the higher antioxidant activity, which might be related to its lower molecular weight, higher mannose proportion and lower degree of acetylation, and higher phenolic content. Our results provide a more accurate basis for the application of DOPs in the pharmaceutical and food industries. [ABSTRACT FROM AUTHOR]

Published
2023
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85. Analysis and Optimization of Landscape Preference Characteristics of Rural Public Space Based on Eye-Tracking Technology: The Case of Huangshandian Village, China.

Author

Su, Tingting, Wang, Kaiping, Li, Shuangshuang, Wang, Xinyan, Li, Huan, Ding, Huanru, Chen, Yanfei, Liu, Chenhui, Liu, Min, and Zhang, Yunlu

Abstract

As an important part of rural space, the public space landscape has a positive influence on tourists and local residents, and also has an important guiding significance for the sustainable development of rural areas. This study expands the previous research on rural public space, taking the "user-oriented" landscape preference as an important entry point, taking Beijing rural public space as the research object, using eye-tracking technology to objectively reflect the degree of users' preference for the landscape, making quantitative analysis through eye-tracking objective data and subjective satisfaction evaluation to explore the subconscious and aesthetic laws of the subjects, and summarizing the internal driving factors leading to its evolution from the summary of phenomena. This paper explores the visual behavior information and significance behind the "subjective space" created by the countryside for the users, intending to provide strategies for landscape optimization and the management of rural public space in an effort to aid the sustainable development of the countryside. [ABSTRACT FROM AUTHOR]

Published
2023
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86. Clinical significance of 18F-FDG PET/CT imaging in 32 cases of gastrointestinal stromal tumors.

Author

Du, Wen, Cui, Guojin, Wang, Kaiping, and Li, Shaojie

Subjects
COMPUTED tomography, GLUCOSE metabolism, GASTROINTESTINAL stromal tumors
Abstract

Objectives: To explore the clinical significance of 18F-FDG metabolic imaging in the diagnosis and biological risk assessment of gastrointestinal stromal tumors (GIST). Methods: This study is a clinical retrospective study. The research subjects were patients with GIST who were admitted to our hospital from January 2014 to December 2019 and underwent 18F-FDG metabolic imaging, and the relationship between biological risk and FDG metabolism was analyzed retrospectively. Results: A total of 32 patients with GIST were included in this study, of which 17 patients had very low and low-risk lesions, and the FDG metabolism level did not increase; five patients had moderate-risk gastric lesions, and the FDG metabolism level was abnormally increased; 10 patients had high-risk lesions, and except for one patient with multiple lesions, the FDG metabolism level of these patients was increased. Conclusions: The level of glucose metabolism is abnormally increased in tumor cells with vigorous mitosis and has higher biological risk. The 18F-FDG metabolism level can determine the biological risk of GIST and whether high-risk lesions involve other tissues and organs, as it more comprehensively reflects the distribution of lesions, the activity of tumor cells and the stage of the disease. [ABSTRACT FROM AUTHOR]

Published
2022
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95. Research On Polarization Characteristics Of a Semiconductor Optical Amplifier Fiber Ring Laser

Author

Zhang Zhie, Wang Kaiping, Li Zhengying, Fu Xuelei, and Wang Honghai

Subjects
Optical amplifier, Physics, Optics, business.industry, Chaotic, Single-mode optical fiber, Ring laser, Polarization-division multiplexing, Oscilloscope, Optical chaos, business, Lasing threshold
Abstract

In this paper, a simple implementation of dual-channel chaotic lasing is realized using a fiber ring laser with an intra-cavity semiconductor optical amplifier (SOA). Due to the high-speed gain saturation and recovery, combined with the strong coupling between the amplitude and the phase in the SOA, chaotic oscillation can be facilitated. Meanwhile, the Kerr effect and the anomalous dispersion in the single-mode fiber causes modulational instability, which strengthens the chaotic behavior, leading to reduced chaotic oscillation threshold. The output optical signals with orthogonal polarizations are split using a polarization beam splitter and detected in parallel by two photodetectors (PD). The electrical outputs are acquired by a real-time oscilloscope with an 8-bit ADC sampling at a rate of 80 GSa/s. Both polarizations exhibit electrical bandwidth up to 13 GHz, which is limited by the analog bandwidth of the PD. While the autocorrelation of each signal shows a typical curve of a random signal, the cross-correlation of the two polarizations contains no significant correlation peak, indicating that the two chaotic signals are independent of each other. Random number generation at a bit rate of 480 Gb/s is then realized using the acquired sequences. The random bits can pass all the randomness tests provided by the NIST SP800-22 test tool. Due to the independence of the two polarizations, this chaotic laser also serves as a promising candidate for chaotic communication exploring polarization division multiplexing.

Published
2020

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