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19 results on '"Han, Zhengyi"'

2. Comparison of the Effects of Adductor Canal and Femoral Nerve Blocks on Postoperative Opioid Consumption and Inflammatory Factor Levels in Elderly Patients After Total Knee Arthroplasty: A Prospective Observational Study.

Author

Han, Zhengyi, Zhang, Yangyang, Xue, Chenxi, Jin, Shiyun, Chen, Qi, and Zhang, Ye

Subjects
TOTAL knee replacement, FEMORAL nerve, OLDER patients, PAIN measurement, C-reactive protein, NERVE block
Abstract

Purpose: Total Knee Arthroplasty (TKA) is a highly invasive procedure causing severe postoperative pain, which hampers early mobility. Effective pain management is crucial for optimal recovery. This study aimed to evaluate how adductor canal block (ACB) and femoral nerve block (FNB) affect opioid use and inflammation factor levels in elderly TKA patients. Methods: This prospective observational study included 120 patients who received TKA, and divided them into three groups, based on the different nerve block technique: ACB, FNB, and no intervention before general anesthesia (CON). Postoperative opioid consumption, pain assessment, inflammation factor, knee function recovery and other clinical indicators were recorded. Results: The CON group had significantly higher cumulative sufentanil consumption compared to the ACB and FNB groups at both 12 h and 48h postoperative (P< 0.001). Compared with the CON group, the ACB and FNB groups persistently had lower pain scores until 12 h at rest and 24 h during motion after surgery. The ACB group showed significantly lower serum concentrations of C-reactive protein (CRP) and interleukin-6 (IL-6) compared to the CON group at 24 h postoperative (P=0.017, P=0.009), and IL-6 levels remained significantly lower at 72 h postoperative (P=0.005). Both ACB and FNB groups achieved earlier ambulation compared to the CON group (P=0.002). On the first day postoperative, both the ACB and FNB groups showed significantly better knee motion (P< 0.001), quadriceps strength (P< 0.001), and daily mobilization (P< 0.001) compared to the CON group. Additionally, the ACB group exhibited superior quadriceps strength (P< 0.001) and daily mobilization (P< 0.001) compared to the FNB group. Conclusion: The ACB and FNB groups exhibited comparable clinical efficacy outcomes in terms of pain scores and opioid consumption. However, the ACB group experienced reduced postoperative inflammation and improved knee recovery, especially in quadriceps strength. [ABSTRACT FROM AUTHOR]

Published
2024
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4. Development of Cable Accessories with SiR Insulation for 320kV HVDC Cables

Author

Xu Ruoyu, Zhou Mingyu, Han Zhengyi, Luo Yi, Wang Haitian, Zhou Yuzhen, and Yang Tong

Subjects
Environmental sciences, GE1-350
Abstract

HVDC cable accessories with environment-friendly insulating material and flexible compatibility other than ethylene propylene diene monomer (EPDM) are demanded in the global market. In this paper, the authors present their newly developed silicone rubber (SiR) insulated cable joints and terminations as a potential answer to that call. Simulation models were built in computer programs. Three most venerable spots in the insulator were identified. SiR insulated accessories with optimised conductivity were produced and tested according to Cigre TB 496 and IEC 62895:2017. The test objects passed the type test with good success. It proved that with proper design, manufacturing and installation, SiR insulated cable accessories are able to provide good service in the power system networks.

Published
2019
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6. Development of European Power Grid and Its Compatibility with Global Energy Interconnection

Author

Han, Zhengyi, Crespi, Giulia, Huang, Tao, Xin, Tan, Zhiyuan, Ma, Fang, Yang, and Han, Huang

Subjects
Global Energy Interconnection(GEI), Ten Years Network Development Plan(TYNDP), European power grid, European Network of Transmission System Operators(ENTSO-E), Global Energy Interconnection(GEI), Ten Years Network Development Plan(TYNDP), European Network of Transmission System Operators(ENTSO-E), European power grid
Published
2020

11. Research on Overvoltage for XLPE Cable in a Modular Multilevel Converter HVDC Transmission System

Author

Han Zhengyi, Jie Yang, Zhiyuan He, Haitian Wang, Junzheng Cao, and George Chen

Subjects
Engineering, business.industry, Surge arrester, 020209 energy, Electrical engineering, Energy Engineering and Power Technology, Type test, 02 engineering and technology, Transmission system, Modular design, Impulse (physics), Inductor, Parasitic capacitance, Overvoltage, 0202 electrical engineering, electronic engineering, information engineering, Electronic engineering, Electrical and Electronic Engineering, business
Abstract

Due to the rapid development of the voltage-source converter (VSC), the demands for HVDC cables have increased significantly. Although more than ten VSC-HVDC projects are under construction and many more are in operations globally, the testing criteria for HVDC XLPE cables are mainly referenced to test guideline TB 496 recommended by CIGRE. Due to the large stray capacitance of the VSC-HVDC cables, the switching impulse overvoltage stress of the cables is the main electrical parameter concerned, a unified overvoltage factor of 2.1 p.u. being generally accepted. However, the switching impulse overvoltage stress of a VSC-HVDC cable system depends on not only the VSC topology but also the cable parameters and the volt-ampere characteristics of the dc cable surge arresters used. This paper studies the switching impulse overvoltage stresses for the dc cable system of a symmetrical monopole VSC-HVDC transmission system using the modular multilevel converter technology. The studies were performed according to the key technical parameters for a typical 1000-MW/320-kV VSC-HVDC transmission scheme, the XLPE dc cable links being assumed. The results show that a switching impulse overvoltage level of 2.3 p.u. should be applied during the type test of the overvoltage capability of the HVDC cables.

Published
2016

15. Design aspects on HVDC cable joints

Author

Ye, Hanyu, primary, Han, Zhengyi, additional, Luo, Yi, additional, Zhuang, Qikai, additional, Fechner, Tobias, additional, Wang, Haitian, additional, and Lei, Xi, additional

Published
2018
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16. Review on HVDC cable terminations

Author

Ye, Hanyu, primary, Fechner, Tobias, additional, Lei, Xianzhang, additional, Luo, Yi, additional, Zhou, Mingyu, additional, Han, Zhengyi, additional, Wang, Haitian, additional, Zhuang, Qikai, additional, Xu, Ruoyu, additional, and Li, Duo, additional

Published
2018
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17. Data recovery algorithm in space charge measurement by PEA method

Author

Wenpeng Li, Haitian Wang, Han Zhengyi, Chao Tang, George Chen, Junzheng Cao, and Zhiyuan He

Subjects
010302 applied physics, Physics, Applied Mathematics, Attenuation, Dielectric, 01 natural sciences, Space charge, Computer Science Applications, Computational Theory and Mathematics, Frequency domain, Distortion, 0103 physical sciences, Dispersion (optics), Calibration, Waveform, Electrical and Electronic Engineering, Algorithm
Abstract

Purpose The pulsed electro-acoustic (PEA) method is widely applied for space charge measurement in solid dielectrics. The signals, however, can be seriously distorted during transmission, especially in non-planar specimens. The aim of this work is to find an efficient algorithm to correctly recover the space charge profile for different types of specimens. Design/methodology/approach The distortion can be associated with both geometry and material (attenuation and dispersion). Hence the recovery algorithm consists of two parts respectively. The influences of geometries, causing the divergences of electric force and acoustic waveform, can be corrected by sets of factors. The attenuation and dispersion of the material can be suppressed based on the transfer function matrix in frequency domain, which could be obtained from calibration. Findings A general algorithm applicable to three kinds of specimens (single-layer, multi-layer and coaxial-geometry dielectrics) has been proposed. Compared with the other two algorithms in literature, the present one offers the most accurate solution while taking relatively shorter time. In addition, this algorithm is applied on signals measured from a planar LDPE sample and the results show that the new algorithm is fairly effective with excellent stability in a real system. Originality/value As one of the most accurate algorithms, the present one is theoretically one third quicker than the others. This algorithm would be helpful in applications calling for large calculations, i.e. 3-D imaging of space charge distribution in XLPE cable.

Published
2016

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