AI Chat Paper
Note: Please note that the following content is generated by AMiner AI. SciOpen does not take any responsibility related to this content.
{{lang === 'zh_CN' ? '文章概述' : 'Summary'}}
{{lang === 'en_US' ? '中' : 'Eng'}}
Chat more with AI
Powered by AMiner. Clicking this button will take you away from SciOpen.
Home Nano Research Article
Article Link
Cite
EndNote(RIS) BibTeX
Collect
Submit Manuscript
Show Outline
Outline
Show full outline
Hide outline
Outline
Show full outline
Hide outline
Research Article

Metasurface-assisted low-frequency performance enhancement of ultra-broadband honeycomb absorber based on carbon nanotubes

Cai-Liang Wang1,2, Shuang Bai1, Pei-Yan Zhao1, Tao Zhou4, Hui-Ya Wang5, Jun-Peng Wang2( ), Luo-Xin Wang3, Guang-Sheng Wang1( )
School of Chemistry, Beihang University, Beijing 100191, China
Aerospace Science and Industry Corporation of Wuhan Magnetoelectricity Co., Ltd., Wuhan 430070, China
College of Materials Science and Engineering, Key Laboratory for New Textile Materials and Applications of Hubei Province, Wuhan Textile University, Wuhan 430200, China
School of Chemistry and Chemical Engineering, Lingnan Normal University, Zhanjiang 524048, China
School of Materials Science and Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, China
Show Author Information

Graphical Abstract

A method for improving low-frequency absorption performance and designing a broadband absorber of honeycomb absorber (HA) by placing a metasurface between two absorptive honeycombs was proposed. A prototype sample has been created and evaluated to validate the approach and concept, which demonstrates high efficiency and broadband absorption with average absorption rates exceeding 90% over the whole frequency range from 1.0 to18.0 GHz.

Abstract

Here, we present a unique method to enhance the low-frequency absorption performance of a honeycomb absorber by integrating a metasurface. The geometrical dimensions of the proposed metasurface have been numerically optimized. The introduction of the metasurface allows exploitation of its robust resonance and superior impedance matching in low-frequency bands, thereby improving microwave absorption properties. The incorporation of the metasurface does not impact the wave transmission performance of the honeycomb core absorber at high-frequency band, thus preserving its high-frequency performance. This broadens the absorption range, leading to an expanded bandwidth. Simulation results reveal that the composite absorber (CA) exhibits strong absorption performance with an incident angle stability up to 45° for both transverse electric (TE) and transverse magnetic (TM) modes. The absorption mechanism of the CA has been investigated by using an equivalent circuit model and electromagnetic field analysis. A prototype was designed, fabricated, and tested to validate the proposed method. Both simulation and measurement results demonstrate that the prototype can achieve an average absorption rate exceeding 90% across a 1.0−18.0 GHz range. This study introduces an innovative technique for creating microwave absorbers for low-frequency wideband applications.

Keywords

impedance matchingmetasurfacelow frequencyradar absorption

Electronic Supplementary Material

Download File(s)
6833_ESM.pdf (887.7 KB)

References

[1]

Li, Y. F.; Li, X. Y.; Li, Q. F.; Zhao, Y. H.; Wang, J. W. Low-energy-consumption fabrication of porous TPU/graphene composites for high-performance microwave absorption and the influence of Fe3O4 incorporation. J. Alloys Compd. 2022, 909, 164627.
Crossref Google Scholar
[2]

Zhang, N.; Chen, P. Z.; Wang, Y.; Zong, M.; Chen, W. X. Supramolecular self-assembly derived Mo2C/FeCo/NC hierarchical nanostructures with excellent wideband microwave absorption properties. Compos. Sci. Technol. 2022, 221, 109325.
Crossref Google Scholar
[3]

Wu, X. H.; Ma, W. J.; Xu, J.; He, P.; Du, Y. Q.; Zhang, Y. T.; Zuo, P. Y.; Qi, H. M.; Zhuang, Q. X. Hierarchical multi-core-shell CoNi@graphite carbon@carbon nanoboxes for highly efficient broadband microwave absorption. ACS Appl. Nano Mater. 2022, 5, 7300–7311.
Crossref Google Scholar
[4]

Zhang, N.; Han, M. Y.; Wang, G. H.; Zhao, Y.; Gu, W. H.; Zhou, M.; Chen, J. B.; Ji, G. B. Achieving broad absorption bandwidth of the Co/carbon absorbers through the high-frequency structure simulator electromagnetic simulation. J. Alloys Compd. 2021, 883, 160918.
Crossref Google Scholar
[5]

Shi, B. S.; Liu, K. R.; Chen, J. S.; Li, B. C.; Wang, B.; Li, D.; Wei, S. C.; Han, Q. Microwave absorption properties of ZnFe2O4/graphite composites prepared by high-temperature ball milling. J. Alloys Compd. 2022, 905, 164210.
Crossref Google Scholar
[6]

Yang, K.; Cui, Y. H.; Wan, L. Y.; Zhang, Q. Y.; Zhang, B. L. MOF-derived magnetic-dielectric balanced Co@ZnO@N-doped carbon composite materials for strong microwave absorption. Carbon 2022, 190, 366–375.
Crossref Google Scholar
[7]

He, L.; Li, X.; Zhao, Y. C.; Zhong, Z. T.; Zhang, J.; Yang, Y.; Xi, X. L. The multilayer structure design of magnetic-carbon composite for ultra-broadband microwave absorption via PSO algorithm. J. Alloys Compd. 2022, 913, 165088.
Crossref Google Scholar
[8]

Huang, Y. X.; Yuan, X. J.; Chen, M. J.; Song, W. L.; Chen, J.; Fan, Q. F.; Tang, L. Q.; Fang, D. L. Ultrathin multifunctional carbon/glass fiber reinforced lossy lattice metastructure for integrated design of broadband microwave absorption and effective load bearing. Carbon 2019, 144, 449–456.
Crossref Google Scholar
[9]

Fan, Q. F.; Yang, X. Z.; Lei, H. S.; Liu, Y. Y.; Huang, Y. X.; Chen, M. J. Gradient nanocomposite with metastructure design for broadband radar absorption. Compos. Part A: Appl. Sci. Manuf. 2020, 129, 105698.
Crossref Google Scholar
[10]

Lyu, Z.; Zhang, B. Z.; Duan, J. P.; Yang, Y. H.; Liu, R.; Wei, Y. Q.; Liu, J. W. Transparent ultra-broadband absorber based on a tree seedling composite structure. J. Phys. D: Appl. Phys. 2022, 55, 095104.
Crossref Google Scholar
[11]

Uddin, A.; Estevez, D.; Qin, F. X. From functional units to material design: A review on recent advancement of programmable microwire metacomposites. Compos. Part A: Appl. Sci. Manuf. 2022, 153, 106734.
Crossref Google Scholar
[12]

Uddin, A.; Estevez, D.; Qin, F. X.; Peng, H. X. Programmable microwire composites: From functional units to material design. J. Phys. D: Appl. Phys. 2020, 53, 155302.
Crossref Google Scholar
[13]

Zheng, X. F.; Qin, F. X.; Wang, H.; Mai, Y. W.; Peng, H. X. Microwave absorbing properties of composites containing ultra-low loading of optimized microwires. Compos. Sci. Technol. 2017, 151, 62–70.
Crossref Google Scholar
[14]

Ye, X. L.; Zhang, J. X.; Ma, X. M.; Li, X.; Yu, H. Facile synthesis of a strong Ni-based composite electromagnetic microwave absorber. J. Phys. Chem. C 2023, 127, 1251–1259.
Crossref Google Scholar
[15]

Bi, S.; Song, Y. Z.; Hou, G. L.; Li, H.; Liu, Z. H.; Hou, Z. L.; Zhang, J. Y. Sandwich nanoarchitectonics of heterogenous CB/CNTs honeycomb composite for impedance matching design and microwave absorption. J. Alloys Compd. 2023, 943, 169154.
Crossref Google Scholar
[16]

Przybył, W.; Januszko, A.; Radek, N.; Szczepaniak, M.; Bogdanowicz, K. A.; Plebankiewicz, I.; Szczodrowska, B.; Mazurczuk, R. Microwave absorption properties of carbonyl iron-based paint coatings for military applications. Def. Technol. 2023, 22, 1–9.
Crossref Google Scholar
[17]
Qiao, J.; Song, Q. H.; Xuan, L. X.; Liu, J. R.; Zhang, X.; Zheng, S. N.; Lin, J. P.; Cai, W. Q.; Zhang, Q. D.; Zeng, Z. H. et al. Dual cross-linked magnetic MXene aerogel with high strength and durability enables multifunctionality. Adv. Funct. Mater., in press, DOI: 10.1002/adfm.202401687.
[18]

Qiao, J.; Song, Q. H.; Zhang, X.; Zhao. S. Y.; Liu, J. R.; Nyström, G.; Zeng, Z. H. Enhancing interface connectivity for multifunctional magnetic carbon aerogels: An in situ growth strategy of metal-organic frameworks on cellulose nanofibrils. Adv. Sci. 2024, 11, 2400403.
Crossref Google Scholar
[19]

Zhang, Y. L.; Ruan, K. P.; Zhou, K.; Gu, J. W. Controlled distributed Ti3C2T x hollow microspheres on thermally conductive polyimide composite films for excellent electromagnetic interference shielding. Adv. Mater. 2023, 35, 2211642.
Crossref Google Scholar
[20]

Yang, W. T.; Qi, X. M.; Sun, J. W.; Yu, L. M.; Dong, Y. B.; Fu, Y. Q.; Zhu, Y. F. A deformable honeycomb sandwich composite felt with excellent microwave absorption performance at a low absorbent loading content. Compos. Struct. 2022, 283, 115140.
Crossref Google Scholar
[21]

Huang, S. L.; Liu, Y. Q.; Wen, K.; Su, X. G.; Liang, C. B.; Duan, H. J.; Zhao, G. Z. Optimization design of a novel microwave absorbing honeycomb sandwich structure filled with magnetic shear-stiffening gel. Compos. Sci. Technol. 2023, 232, 109883.
Crossref Google Scholar
[22]

Huang, Y. X.; Wu, D.; Chen, M. J.; Zhang, K.; Fang, D. N. Evolutionary optimization design of honeycomb metastructure with effective mechanical resistance and broadband microwave absorption. Carbon 2021, 177, 79–89.
Crossref Google Scholar
[23]

Zhang, Y. L.; Kong, J.; Gu, J. W. New generation electromagnetic materials: Harvesting instead of dissipation solo. Sci. Bull. 2022, 67, 1413–1415.
Crossref Google Scholar
[24]

Guo, Y. Q.; Ruan, K. P.; Wang, G. S.; Gu, J. W. Advances and mechanisms in polymer composites toward thermal conduction and electromagnetic wave absorption. Sci. Bull. 2023, 68, 1195–1212.
Crossref Google Scholar
[25]

Zhang, M. Y.; Sun, X. H.; Cai, X. D.; Zhang, X. L. Wu, Y. F.; Zhang, X. Y.; Wu, G. H.; Wang, X. W. Large microsphere structure of a Co/C Composite derived from Co-MOF with excellent wideband electromagnetic microwave absorption performance. ACS Appl. Mater. Interfaces 2023, 15, 59681–59692.
Crossref Google Scholar
[26]

Shi, K. Z.; Sun, Y. W.; Hu, R.; He, S. L. Ultra-broadband and wide-angle nonreciprocal thermal emitter based on Weyl semimetal metamaterials. Nanophotonics 2024, 13, 737–747.
Crossref Google Scholar
[27]

He, Y.; Feng, W. S.; Guo, S.; Wei J. F.; Zhang, Y. L.; Huang, Z.; Li, C. L.; Miao, L.; Jiang. J. J. Design of a dual-band electromagnetic absorber with frequency selective surface. IEEE Antenn. Wirel. Pr. 2020, 19, 841–845.
Crossref Google Scholar
[28]

Dai, H. Y.; Ye, F. J.; Chen, Z. P.; Li, T.; Liu, D. W. The effect of ion doping at different sites on the structure, defects and multiferroic properties of BiFeO3 ceramics. J. Alloys Compd. 2018, 734, 60–65.
Crossref Google Scholar
[29]

Dai, H. Y.; Chen, Z. P.; Li, T.; Li, Y. Microstructure and properties of Sm-substituted BiFeO3 ceramics. J. Rare Earths 2012, 30, 1123–1128.
Crossref Google Scholar
[30]

Bi, S.; Song, Y. Z.; Hou, G. L.; Li, H.; Yang, N. J.; Liu, Z. H. Lightweight and compression-resistant carbon-based sandwich honeycomb absorber with excellent electromagnetic wave absorption. Nanomaterials 2022, 12, 2622.
Crossref Google Scholar
[31]

He, F.; Si, K. X.; Li, R.; Zha, D. C.; Dong, J. X.; Miao, L.; Bie, S. W.; Jiang, J. J. Frequency selective surface composites with honeycomb absorbing structure for broadband applications. IEEE Trans. Antennas Propag. 2022, 70, 8643–8647.
Crossref Google Scholar
[32]

Chen, J. Y.; Han, Y.; Feng, S. Y.; Chang, Y. M. Design of ultra-wideband absorbers based on aramid honeycomb structures. In Proceedings of 2022 IEEE MTT-S International Wireless Symposium, Harbin, China, 2022, pp 1–3.
Crossref Google Scholar
[33]

Pang, H. F.; Duan, Y. P.; Dai, X. H.; Huang, L. X.; Yang, X.; Zhang, T.; Liu, X. J. The electromagnetic response of composition-regulated honeycomb structural materials used for broadband microwave absorption. J. Mater. Sci. Technol. 2021, 88, 203–214.
Crossref Google Scholar
[34]

Dai, H. Y.; Liu, H. Z.; Peng, K.; Ye, F. J.; Li, T.; Chen, J.; Chen, Z. P. Correlation between vacancy defects and magnetic properties of the GdMn1– x Zn x O3 multiferroic ceramics studied by positron annihilation. Mater. Res. Rull. 2019, 119, 110565.
Crossref Google Scholar
[35]

Zheng, L.; Niu, L.; Wang, T.; Li, X. C.; Wang, X.; Gong, R. Z. Integrated lightweight gradient honeycomb metastructure with microwave absorption and mechanical properties: Analysis, design, and verification. Compos. Struct. 2023, 305, 116464.
Crossref Google Scholar
[36]

Yadav, R.; Panwar, R. Effective Medium approximation fused optimization strategy derived new kind of honeycomb microwave absorbing structure. IEEE Trans. Magn. 2022, 58, 2501311.
Crossref Google Scholar
[37]

Zhang, X.; Tian, X. L.; Wu, N.; Zhao, S. Y.; Qin, Y. T.; Pan, F.; Yue, S. Y.; Ma, X. Y.; Qiao, J.; Xu, W. et al. Metal-organic frameworks with fine-tuned interlayer spacing for microwave absorption. Sci. Adv. 2024, 10, eadl6498.
Crossref Google Scholar
[38]

Liu, Q. H.; Cao, Q.; Bi, H.; Liang, C. Y.; Yuan, K. P.; She, W.; Yang, Y. J.; Che, R. C. CoNi@SiO2@TiO2 and CoNi@Air@TiO2 microspheres with strong wideband microwave absorption. Adv. Mater. 2016, 28, 486–490.
Crossref Google Scholar
[39]
He, M. K.; Hu, J. W.; Yan, H.; Zhong, X.; Zhang, Y. L.; Liu, P. B.; Kong, J.; Gu, J. W. Shape anisotropic chain-like CoNi/Polydimethylsiloxane composite films with excellent low-frequency microwave absorption and high thermal conductivity. Adv. Funct. Mater., in press, DOI: 10.1002/adfm.202316691.
[40]

Wei, C. H.; Shi, L. Z.; Li, M. Q.; He, M. K.; Li, M. J.; Jing, X. R.; Liu, P. B.; Gu, J. W. Hollow engineering of sandwich NC@Co/NC@MnO2 composites toward strong wideband electromagnetic wave attenuation. J. Mater. Sci. Technol. 2024, 175, 194–203.
Crossref Google Scholar
[41]

Liu, Y. X.; He, M. K.; Hu, J. W.; Liu, P. B.; Liu, Z. W.; Ma, Z. L.; Ju, W. B.; Gu, J. W. Hierarchical design of FeCo-based microchains for enhanced microwave absorption in C band. Nano Res. 2023, 16, 1773–1778.
Crossref Google Scholar
[42]

Kwak, B. S.; Jeong, G. W.; Choi, W. H.; Nam, Y. W. Microwave-absorbing honeycomb core structure with nickel-coated glass fabric prepared by electroless plating. Compos. Struct. 2021, 256, 113148.
Crossref Google Scholar
[43]

He, Y. F.; Gong, R. Z.; Cao, H.; Wang, X.; Zheng, Y. Preparation and microwave absorption properties of metal magnetic micropowder-coated honeycomb sandwich structures. Smart Mater. Struct. 2007, 16, 1501–1505.
Crossref Google Scholar
[44]

Khurram, A. A.; Ali, N.; Rakha, S. A.; Zhou, P. H.; Munir, A. Optimization of the carbon coating of honeycomb cores for broadband microwave absorption. IEEE Trans. Electromagn. Compat. 2014, 56, 1061–1066.
Crossref Google Scholar
[45]

Zhong, X.; He, M. K.; Zhang, C. Y.; Guo, Y. Q.; Hu, J. W.; Gu, J. W. Heterostructured BN@Co-C@C endowing polyester composites excellent thermal conductivity and microwave absorption at C band. Adv. Funct. Mater. 2024, 34, 2313544.
Crossref Google Scholar
[46]

Liu, P. B.; Gao, S.; Wang, Y.; Zhou, F. T.; Huang, Y.; Luo, J. H. Composites Parts B. Metal-organic polymer coordination materials derived Co/N-doped porous carbon composites for frequency-selective microwave absorption. Compos. Part B: Eng. 2020, 202, 108406.
Crossref Google Scholar
[47]

Liu, P. B.; Gao, S.; Liu, X. D.; Huang, Y.; He, W. J.; Li, Y. T. Rational construction of hierarchical hollow CuS@CoS2 nanoboxes with heterogeneous interfaces for high-efficiency microwave absorption materials. Compos. Parts B: Eng. 2020, 192, 107992.
Crossref Google Scholar
[48]

Liu, P. B.; Li, Y. R.; Xu, H. X.; Shi, L. Z.; Kong, J.; Lv, X. W.; Zhang, J. C.; Che, R. C. Hierarchical Fe–Co@TiO2 with incoherent heterointerfaces and gradient magnetic domains for electromagnetic wave absorption. ACS Nano 2024, 18, 560–570.
Crossref Google Scholar
[49]
Wang, S. S.; Feng, D. Y.; Zhang, Z. M.; Liu, X.; Ruan, K. P.; Guo, Y. Q.; Gu, J. W. Highly thermally conductive polydimethylsiloxane composites with controllable 3D GO@f-CNTs networks via self-sacrificing template method. Chin. J. Polym. Sci., in press, 10.1007/s10118-024-3098-4.
[50]

Ruan, K. P.; Shi, X. T.; Zhang, Y. L.; Guo, Y. Q.; Zhong, X.; Gu, J. W. Electric-field-induced alignment of functionalized carbon nanotubes inside thermally conductive liquid crystalline polyimide composite films. Angew. Chem., Int. Ed. 2023, 62, e202309010.
Crossref Google Scholar
[51]

Wang, M. M.; Wang, R. M.; Dai, H. Y.; Li, T.; Sun, Y.; Liu, D. W.; Yan, F. F.; Ping, T. D. A comparative study of the structure, defects, optical, dielectric, and magnetic properties of GdMnO3 multiferroic ceramics synthesized by solid-state reaction and sol-gel methods. Ceram. Int. 2022, 48, 21622–21630.
Crossref Google Scholar
[52]

Wang, M. M.; Wang, R. M.; Dai, H. Y.; Li, T.; Sun, Y.; Liu, D. W.; Yan, F. F.; Xing, X. B. The effects of hot isostatic pressing temperature on the structure and properties in GdMnO3 ceramics. Ceram. Int. 2022, 48, 3685–3694.
Crossref Google Scholar
[53]

Yan, F. F.; Liu, Z. Y.; Chen, J.; Liu, H. Z.; Dai, X. H.; Zhao, R. J.; Dai, H. Y. Modulating the structure, vacancy defects, magnetic and dielectric properties in multiferroic GdMnO3 ceramics by alkaline earth ion substitution. Ceram. Int. 2022, 48, 33135–33142.
Crossref Google Scholar
[54]

Dai, H. Y.; Li, T.; Chen, Z. P.; Liu, D. W.; Xue, R. Z.; Zhao, C. Z.; Liu, H. Z.; Huang, N. K. Studies on the structural, electrical and magnetic properties of Ce-doped BiFeO3 ceramics. J. Alloys Compd. 2016, 672, 182–189.
Crossref Google Scholar
[55]

Li, Y. F.; Wang, J. F.; Zhang, J. Q.; Qu, S. B.; Pang, Y. Q.; Zheng, L.; Yan, M. B.; Xu, Z.; Zhang, A. X. Ultra-wide-band microwave composite absorbers based on phase gradient metasurfaces. Prog. Electromagn. Res. M 2014, 40, 9–18.
Crossref Google Scholar
[56]

Qiu, K. P.; Feng, S. Q. A novel metamaterial absorber with perfect wave absorption obtained by layout design. J. Electromagn. Waves Appl. 2016, 30, 523–535.
Crossref Google Scholar
[57]

Wang, Y.; Chen, S. J.; Liu, S. S.; Wu, J.; Wang, Y. C.; Ding, X. X.; Yang, H. L. A novel ultra-broadband absorber based on carbon-coated honeycomb panels combined with metamaterials. J. Phys. D: Appl. Phys. 2022, 55, 455106.
Crossref Google Scholar
[58]

He, F.; Si, K. X.; Zha, D. C.; Li, R.; Zhang, Y. L.; Dong, J. X.; Miao, L.; Bie, S. W.; Jiang, J. J. Broadband microwave absorption properties of a frequency-selective surface embedded in a patterned honeycomb absorber. IEEE Trans. Electromagn. Compat. 2021, 63, 1290–1294.
Crossref Google Scholar
[59]

Baek, S. M.; Lee, W. J.; Kim, S. Y.; Kim, S. S. A study on the microwave absorbing honeycomb core embedded with conductive periodic patterned surfaces for the effective dielectric constant. Compos. Struct. 2022, 289, 115471.
Crossref Google Scholar
[60]

Landy, N. I.; Sajuyigbe, S.; Mock, J. J.; Smith, D. R.; Padilla, W. J. Perfect metamaterial absorber. Phys. Rev. Lett. 2008, 100, 207402.
Crossref Google Scholar
[61]

Song, J.; Wang, L. L.; Li, M. H.; Dong, J. F. A dual-band metamaterial absorber with adjacent absorption peaks. J. Phys. D: Appl. Phys. 2018, 51, 385105.
Crossref Google Scholar
[62]

Ma, Y.; Wang, J. B.; Shi, L. H.; Xue, S. Y.; Ran, Y. Z.; Li, J.; Liu, Y. C. Ultra-wideband, optically transparent, and flexible microwave metasurface absorber. Opt. Mater. Express 2021, 11, 2206–2218.
Crossref Google Scholar
[63]
Tiwari, P.; Pathak, S. K.; Anitha, V. P. Design, development and characterization of wide incidence angle and polarization insensitive metasurface absorber based on resistive-ink for X and Ku band RCS reduction. Waves Random Complex Med., in press, DOI: 10.1080/17455030.2021.1972182.
[64]

Fu, C. F.; Zhang, L.; Liu, L. J.; Dong, S. H.; Yu, W. J.; Han, L. F. RCS reduction on patterned graphene-based transparent flexible metasurface absorber. IEEE Trans. Antennas Propag. 2023, 71, 2005–2010.
Crossref Google Scholar
[65]

Yao, L. F.; Li, M. H.; Zhai, X. M.; Wang, H. B.; Dong, J. F. On the miniaturization of polarization insensitive wide angle metamaterial absorber. Appl. Phys. A 2016, 122, 61.
Crossref Google Scholar
Nano Research
Volume 17 Issue 9,
September 2024
Pages 8542-8551
DOI: 10.1007/s12274-024-6833-9
Cite this article:
Wang C-L, Bai S, Zhao P-Y, et al. Metasurface-assisted low-frequency performance enhancement of ultra-broadband honeycomb absorber based on carbon nanotubes. Nano Research, 2024, 17(9): 8542-8551. https://doi.org/10.1007/s12274-024-6833-9
Topics:
Carbon nanotubes
Part of a topical collection:
EM Wave Functional Materials

278

Views

0

Crossref

0

Web of Science

0

Scopus

0

CSCD

Altmetrics
Received: 23 May 2024
Revised: 14 June 2024
Accepted: 17 June 2024
Published: 03 August 2024
© Tsinghua University Press 2024
Return