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Li Z, Guo Z, Yang Y. Preparation and Appraisal of High‐Modulus Resin‐Based Composites Reinforced by Silica‐Coated Multi‐Walled Carbon Nanotubes. ChemistrySelect 2023. [DOI: 10.1002/slct.202203881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
Affiliation(s)
- Zhihua Li
- Key Laboratory of Nonferrous Metal Materials Science and Engineering of Ministry of Education Central South University Changsha 410083 People's Republic of China
- School of Materials Science and Engineering Central South University Changsha 410083 People's Republic of China
| | - Ziteng Guo
- Key Laboratory of Nonferrous Metal Materials Science and Engineering of Ministry of Education Central South University Changsha 410083 People's Republic of China
- School of Materials Science and Engineering Central South University Changsha 410083 People's Republic of China
| | - Yu Yang
- Key Laboratory of Nonferrous Metal Materials Science and Engineering of Ministry of Education Central South University Changsha 410083 People's Republic of China
- School of Materials Science and Engineering Central South University Changsha 410083 People's Republic of China
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Curing Regime-Modulating Insulation Performance of Anhydride-Cured Epoxy Resin: A Review. MOLECULES (BASEL, SWITZERLAND) 2023; 28:molecules28020547. [PMID: 36677605 PMCID: PMC9867423 DOI: 10.3390/molecules28020547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 12/28/2022] [Accepted: 01/04/2023] [Indexed: 01/09/2023]
Abstract
Anhydride-cured bisphenol-A epoxy resin is widely used in the support, insulation and sealing key components of electrical and electronic equipment due to their excellent comprehensive performance. However, overheating and breakdown faults of epoxy resin-based insulation occur frequently under conditions of large current carrying and multiple voltage waveforms, which seriously threaten the safe and stable operation of the system. The curing regime, including mixture ratio and combination of curing time and temperature, is an important factor to determine the microstructure of epoxy resin, and also directly affects its macro performances. In this paper, the evolution of curing kinetic models of anhydride-cured epoxy resin was introduced to determine the primary curing regime. The influences of curing regime on the insulation performance were reviewed considering various mixture ratios and combinations of curing time and temperature. The curing regime-dependent microstructure was discussed and attributed to the mechanisms of insulation performance.
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Design & Optimization of Large Cylindrical Radomes with Subcell and Non-Orthogonal FDTD Meshes Combined with Genetic Algorithms. ELECTRONICS 2021. [DOI: 10.3390/electronics10182263] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The word radome is a contraction of radar and dome. The function of radomes is to protect antennas from atmospheric agents. Radomes are closed structures that protect the antennas from environmental factors such as wind, rain, ice, sand, and ultraviolet rays, among others. The radomes are passive structures that introduce return losses, and whose proper design would relax the requirement of complex front-end elements such as amplifiers. The radome consists mostly in a thin dielectric curved shape cover and sometimes needs to be tuned using metal inserts to cancel the capacitive performance of the dielectric. Radomes are in the near field region of the antennas and a full wave analysis of the antenna with the radome is the best approach to analyze its performance. A major numerical problem is the full wave modeling of a large radome-antenna-array system, as optimization of the radome parameters minimize return losses. In the present work, the finite difference time domain (FDTD) combined with a genetic algorithm is used to find the optimal radome for a large radome-antenna-array system. FDTD uses general curvilinear coordinates and sub-cell features as a thin dielectric slab approach and a thin wire approach. Both approximations are generally required if a problem of practical electrical size is to be solved using a manageable number of cells and time steps in FDTD inside a repetitive optimization loop. These approaches are used in the full wave analysis of a large array of crossed dipoles covered with a thin and cylindrical dielectric radome. The radome dielectric has a thickness of ~λ/10 at its central operating frequency. To reduce return loss a thin helical wire is introduced in the radome, whose diameter is ~0.0017λ and the spacing between each turn is ~0.3λ. The genetic algorithm was implemented to find the best parameters to minimize return losses. The inclusion of a helical wire reduces return losses by ~10 dB, however some minor changes of radiation pattern could distort the performance of the whole radome-array-antenna system. A further analysis shows that desired specifications of the system are preserved.
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Qin Y, Zhang S, Han S, Xu T, Liu C, Xi M, Yu X, Li N, Wang Z. Voltage-Stabilizer-Grafted SiO 2 Increases the Breakdown Voltage of the Cycloaliphatic Epoxy Resin. ACS OMEGA 2021; 6:15523-15531. [PMID: 34151130 PMCID: PMC8210426 DOI: 10.1021/acsomega.1c02108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 05/24/2021] [Indexed: 06/13/2023]
Abstract
Cycloaliphatic epoxy (CE) resin plays a vital role in insulation equipment due to its excellent insulation and processability. However, the insufficient ability of CE to confine electrons under high voltage often leads to an electric breakdown, which limits its wide applications in high-voltage insulation equipment. In this work, the interface effect of inorganic nano-SiO2 introduces deep traps to capture electrons, which is synergistic with the inherent ability of the voltage stabilizer m-aminobenzoic acid (m-ABA) to capture high-energy electrons through collision. Therefore, the insulation failure rate is reduced owing to doping of the functionalized nanoparticles of the m-ABA-grafted nano-SiO2 (m-ABA-SiO2) into the CE. It is worth noting that the breakdown field strength of this m-ABA-SiO2/CE reaches 53 kV/mm, which is 40.8% higher than that of pure CE. In addition, the tensile strength and volume resistivity of m-ABA-SiO2/CE are increased by 29.1 and 140%, respectively. Meanwhile, the glass transition temperature was increased by about 25 °C and reached 213 °C. This work proves that the comprehensive performance of CE-based nanocomposites is effectively improved by m-ABA-SiO2 nanoparticles, showing great application potential in high-voltage insulated power equipment.
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Affiliation(s)
- Yi Qin
- Institute
of Solid State Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui 230031, China
- Department
of Chemistry, University of Science and
Technology of China, Hefei 230026, China
| | - Shudong Zhang
- Institute
of Solid State Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui 230031, China
- Key
Laboratory of Photovoltaic and Energy Conservation Materials, Hefei
Institutes of Physical Science, Chinese
Academy of Sciences, Hefei 230031, China
| | - Shuai Han
- Institute
of Solid State Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui 230031, China
- Department
of Chemistry, University of Science and
Technology of China, Hefei 230026, China
| | - Tingting Xu
- Institute
of Solid State Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui 230031, China
- Department
of Chemistry, University of Science and
Technology of China, Hefei 230026, China
| | - Cui Liu
- Institute
of Solid State Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui 230031, China
- Key
Laboratory of Photovoltaic and Energy Conservation Materials, Hefei
Institutes of Physical Science, Chinese
Academy of Sciences, Hefei 230031, China
| | - Min Xi
- Institute
of Solid State Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui 230031, China
- Key
Laboratory of Photovoltaic and Energy Conservation Materials, Hefei
Institutes of Physical Science, Chinese
Academy of Sciences, Hefei 230031, China
| | - Xinling Yu
- Institute
of Solid State Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui 230031, China
- Key
Laboratory of Photovoltaic and Energy Conservation Materials, Hefei
Institutes of Physical Science, Chinese
Academy of Sciences, Hefei 230031, China
| | - Nian Li
- Institute
of Solid State Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui 230031, China
- Key
Laboratory of Photovoltaic and Energy Conservation Materials, Hefei
Institutes of Physical Science, Chinese
Academy of Sciences, Hefei 230031, China
| | - Zhenyang Wang
- Institute
of Solid State Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui 230031, China
- Key
Laboratory of Photovoltaic and Energy Conservation Materials, Hefei
Institutes of Physical Science, Chinese
Academy of Sciences, Hefei 230031, China
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