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Liu, D., Wang, C., Gonzalez-Libreros, J., Tu, Y., Elfgren, L. & Sas, G. (2024). Modified calculation model of train-induced aerodynamic pressure on vertical noise barriers considering the train geometry effect. Journal of Wind Engineering and Industrial Aerodynamics, 249, Article ID 105750.
Open this publication in new window or tab >>Modified calculation model of train-induced aerodynamic pressure on vertical noise barriers considering the train geometry effect
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2024 (English)In: Journal of Wind Engineering and Industrial Aerodynamics, ISSN 0167-6105, E-ISSN 1872-8197, Vol. 249, article id 105750Article in journal (Refereed) Published
Abstract [en]

High-speed trains (HSTs) generate air disturbance, leading to significant aerodynamic pressure on the noise barriers. Differences in train geometry result in variations in the aerodynamic pressure on noise barriers, implying that existing European standard calculation models may not necessarily be suitable for all types of HSTs. In this paper, the influence of the width, height, and nose length of the train on the aerodynamic pressure on vertical noise barriers was studied using computational fluid dynamics (CFD) simulations. Results showed that taller and wider trains result in greater aerodynamic loads on noise barriers. Conversely, an increase in the nose length of a train leads to a reduction in such pressure. Using grey relational analysis, correlation of various factors with the train-induced aerodynamic pressure is, from strong to weak: distance to the track center, width, height, and nose length of the train. Building upon the EN 14067-4 calculation model, the shape coefficients of trains with varying geometric characteristics were derived using the simulation data obtained in this study. A modified pressure calculation model was established accounting for the differences in geometric features of HSTs and pressure distribution in the vertical direction of noise barriers and validated using relevant data from the literature.

Place, publisher, year, edition, pages
Elsevier, 2024
Keywords
Aerodynamic pressure, Computational fluid dynamics simulation, Pressure calculation model, Train geometry, Vertical noise barrier
National Category
Fluid Mechanics and Acoustics
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-101567 (URN)10.1016/j.jweia.2024.105750 (DOI)2-s2.0-85191294975 (Scopus ID)
Funder
Swedish Transport Administration, BBT-2019-022
Note

Validerad;2024;Nivå 2;2024-06-28 (joosat);

Full text: CC BY License

Available from: 2023-10-04 Created: 2023-10-04 Last updated: 2024-06-28Bibliographically approved
Jin, J., Liu, D. & Tu, Y. (2024). Numerical Simulation of Aerodynamic Pressure on Sound Barriers from High-Speed Trains with Different Nose Lengths. Applied Sciences, 14(7), Article ID 2898.
Open this publication in new window or tab >>Numerical Simulation of Aerodynamic Pressure on Sound Barriers from High-Speed Trains with Different Nose Lengths
2024 (English)In: Applied Sciences, E-ISSN 2076-3417, Vol. 14, no 7, article id 2898Article in journal (Refereed) Published
Abstract [en]

For high-speed railway sound barriers, determining the aerodynamic pressure generated by high-speed trains is crucial for their structural design. This paper investigates the distribution of aerodynamic pressure on the sound barrier caused by high-speed trains with different nose lengths, utilizing the computational fluid dynamics (CFD) simulation method. The accuracy of the numerical simulation method employed is verified through comparison with field test results from the literature. Research findings reveal that when a high-speed train passes through a sound barrier, significant “head wave” and “wake wave” effects occur, with the pressure peak of the “head wave” being notably greater than that of the “wake wave”. As the distance between the sound barrier and the center of the train gradually increases, the aerodynamic pressure on the sound barrier gradually decreases. The nose length of the train has a considerable impact on the aerodynamic pressure exerted on the sound barrier. The streamlined shape of longer-nose trains can significantly reduce the aerodynamic effects on the sound barrier, resulting in a notably smaller pressure peak compared to shorter-nose trains. Finally, by establishing the relationship between the train nose length and the aerodynamic pressure peak, a calculation formula for the train-induced aerodynamic pressure acting on the sound barrier is proposed, taking into account the nose length of the high-speed train.

Place, publisher, year, edition, pages
MDPI, 2024
Keywords
aerodynamic pressure, sound barrier, high-speed trains, fluid dynamics, numerical simulation, nose length of high-speed train
National Category
Fluid Mechanics and Acoustics Energy Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-105172 (URN)10.3390/app14072898 (DOI)001200850500001 ()
Note

Validerad;2024;Nivå 2;2024-04-23 (signyg);

Funder: Natural Science Foundation of China (51378104); Jiangsu Province (BZ2021011); Fundamental Research Funds for the Central Universities (2242022k30030, 2242022k30031);

Full text license: CC BY 4.0

Available from: 2024-04-22 Created: 2024-04-22 Last updated: 2024-04-24Bibliographically approved
Liu, D., Wang, C., Guo, T., Gonzalez-Libreros, J., Ge, Y., Tu, Y., . . . Sas, G. (2024). Time–depth dependent chloride diffusion coefficient of self-compacting concrete. Magazine of Concrete Research, 76(12), 600-616
Open this publication in new window or tab >>Time–depth dependent chloride diffusion coefficient of self-compacting concrete
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2024 (English)In: Magazine of Concrete Research, ISSN 0024-9831, E-ISSN 1751-763X, Vol. 76, no 12, p. 600-616Article in journal (Refereed) Published
Place, publisher, year, edition, pages
ICE Publishing, 2024
National Category
Civil Engineering Materials Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-103740 (URN)10.1680/jmacr.23.00237 (DOI)001134369300001 ()2-s2.0-85180960487 (Scopus ID)
Note

Validerad;2024;Nivå 2;2024-05-21 (joosat);

Available from: 2024-01-16 Created: 2024-01-16 Last updated: 2024-05-21Bibliographically approved
Liu, D., Wang, C., Gonzalez-Libreros, J., Guo, T., Cao, J., Tu, Y., . . . Sas, G. (2023). A review of concrete properties under the combined effect of fatigue and corrosion from a material perspective. Construction and Building Materials, 369, Article ID 130489.
Open this publication in new window or tab >>A review of concrete properties under the combined effect of fatigue and corrosion from a material perspective
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2023 (English)In: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 369, article id 130489Article, review/survey (Refereed) Published
Abstract [en]

When in use, reinforced concrete bridge structures not only experience high-frequency fatigue loading caused by passing vehicles, but also suffer from the effects of a corrosive environment. In addition to fatigue damage to reinforcement, long-term fatigue loading also causes concrete cracking and deterioration of pore structures, thereby accelerating the ingress of external corrosive substances and reducing concrete durability. Long-term exposure to a corrosive environment also reduces the performance of concrete and causes corrosion of reinforcement materials, affecting the fatigue performance of the structure. Therefore, there is a combined effect between fatigue loads and corrosion on concrete. This paper is a review of the current literature from a material perspective on the performance degradation of concrete under the combined action of fatigue loading and corrosion, that is, carbonation, chloride ion attack, freeze–thaw cycles, and sulphate attack. The paper includes (1) a description of a test method for examining the combined action of fatigue loading and corrosion, (2) a summary of performance degradation of concrete under the combined effect of fatigue loading and corrosion, and (3) an introduction to durability deterioration models considering fatigue damage, and fatigue models that can account for corrosion. Finally, potential future research on concrete under the combined effect of fatigue loading and corrosion is described.

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
Concrete, Fatigue load, Corrosion, Combined action, Carbonation, Chloride attack, Freeze–thaw cycles, Sulphate attack, Deterioration, Modelling
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-95539 (URN)10.1016/j.conbuildmat.2023.130489 (DOI)000927776800001 ()2-s2.0-85147195723 (Scopus ID)
Funder
Swedish Transport Administration
Note

Validerad;2023;Nivå 2;2023-02-08 (hanlid);

Funder: FOI-BBT program (BBT-2019-022)

Available from: 2023-02-08 Created: 2023-02-08 Last updated: 2023-04-21Bibliographically approved
Liu, D., Wang, C., Gonzalez-Libreros, J., Tu, Y., Elfgren, L. & Sas, G. (2023). A review on aerodynamic load and dynamic behavior of railway noise barriers when high-speed trains pass. Journal of Wind Engineering and Industrial Aerodynamics, 239, Article ID 105458.
Open this publication in new window or tab >>A review on aerodynamic load and dynamic behavior of railway noise barriers when high-speed trains pass
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2023 (English)In: Journal of Wind Engineering and Industrial Aerodynamics, ISSN 0167-6105, E-ISSN 1872-8197, Vol. 239, article id 105458Article in journal (Refereed) Published
Abstract [en]

Noise barriers need to be installed along high-speed railway lines to protect nearby inhabitants from the noise pollution caused by the running of high-speed trains (HSTs). The vertical noise barrier is the main structural type. However, when an HST passes through the noise barriers sited along the track, significant and transient aerodynamic pressure will act on the surface of the noise barriers, resulting in strong dynamic responses and even fatigue damage. Therefore, it is important to determine the train-induced aerodynamic load on the barrier surface and analyze the dynamic behaviors of the noise barriers under such a load for its structural design and to guarantee its safety and durability. This paper is a systematic review of the current literature on the aerodynamic load and dynamic behavior of vertical noise barriers; it includes (1) a summary and analysis of characteristics of such aerodynamic pressure and relevant influencing factors, (2) an introduction to measurement methods of aerodynamic load and relevant pressure models on the surface of noise barriers, and (3) a description of the dynamic response and fatigue analysis of noise barriers under such loads. Finally, potential further studies on this topic are discussed, and conclusions are drawn.

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
Noise barrier, Railway, High-speed train, Aerodynamic load, Dynamic response, Fatigue
National Category
Vehicle Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-98162 (URN)10.1016/j.jweia.2023.105458 (DOI)001015391400001 ()2-s2.0-85160798389 (Scopus ID)
Funder
Swedish Transport Administration, “Excellence Area 4” and FOI-BBT program (grant number BBT-2019-022)
Note

Validerad;2023;Nivå 2;2023-06-12 (joosat);

Licens fulltext: CC BY License

Available from: 2023-06-12 Created: 2023-06-12 Last updated: 2024-03-07Bibliographically approved
Liu, D. (2023). Characterization of train-induced aerodynamic loads on high-speed railway vertical noise barriers. (Licentiate dissertation). Luleå: Luleå tekniska universitet
Open this publication in new window or tab >>Characterization of train-induced aerodynamic loads on high-speed railway vertical noise barriers
2023 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

High-Speed Railway (HSR) technology requires the deployment of noise barriers to mitigate noise pollution affecting nearby residents. As train speeds increase, so does the magnitude of aerodynamic effects such as aerodynamic noise and the pressure on these barriers, meaning that these structures require robust sound insulation and structural load-bearing capacities. Train-induced aerodynamic loads must therefore be accounted for in the structural design of HSR noise barriers, and accurate characterization of these loads is vital for ensuring noise barrier performance and safety.

Current European standards primarily evaluate aerodynamic loads on noise barriers based on train speed and the distance to the track centre. However, geometric differences between high-speed trains (HSTs) from different countries and regions necessitate the validation and potential revision of existing load calculation models. This thesis aims to enhance the characterization of train-induced aerodynamic pressure on HSR noise barriers and develop more accurate models for its calculation, focusing on the most common barrier type—vertical noise barriers.

Initially, a thorough literature review was conducted to assimilate current knowledge on this topic and pinpoint existing gaps and challenges. Multiple factors including the geometric properties of trains and the heights of noise barriers were then analysed using computational fluid dynamics (CFD) simulations to evaluate their impact on the train-induced aerodynamic pressure on vertical noise barriers. Finally, the suitability of existing pressure calculation models was evaluated using literature data and a modified calculation model building on the EN 14067-4 model was developed. 

A key finding is that the general applicability of existing pressure calculation models is limited because of the wide variation in HST geometries and noise barrier heights. The amplitude of train-induced aerodynamic pressure on vertical noise barriers increases with train height and width but decreases as nose length increases. While taller noise barriers experience greater aerodynamic pressures, the in-crease in pressure with barrier height is not significant. The proposed modified pressure calculation model that accounts for train geometry and the height distribution coefficient predicts the train-induced aerodynamic pressure on vertical noise barriers more accurately than existing models and could thus improve the structural design and safety of HSR noise barriers across a wide range of conditions.

Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 2023
Series
Licentiate thesis / Luleå University of Technology, ISSN 1402-1757
Keywords
Aerodynamic pressure, Computational fluid dynamics, Train geometry, High-speed railway, High-speed train, Load calculation model, Vertical noise barrier
National Category
Fluid Mechanics and Acoustics
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-101574 (URN)978-91-8048-399-5 (ISBN)978-91-8048-400-8 (ISBN)
Presentation
2023-12-08, F1031, Luleå university of technology, Luleå, 13:30 (English)
Opponent
Supervisors
Funder
Swedish Transport Administration, BBT-2019-022Swedish Transport Administration, Excellence Area 4
Available from: 2023-10-12 Created: 2023-10-12 Last updated: 2023-11-17Bibliographically approved
Liu, D., Wang, C., Gonzalez-Libreros, J., Enoksson, O., Hojsten, T., Tu, Y., . . . Sas, G. (2023). Numerical Analysis of High-Speed Train Induced Aerodynamic Load on Noise Barrier Considering Wind Effect. In: Alper Ilki, Derya Çavunt, Yavuz Selim Çavunt (Ed.), Building for the Future: Durable, Sustainable, Resilient - Proceedings of the fib Symposium 2023 - Volume 2: . Paper presented at International Symposium of the International Federation for Structural Concrete, fib Symposium 2023, Istanbul, Turkey, June 5-7, 2023 (pp. 332-341). Springer, 2
Open this publication in new window or tab >>Numerical Analysis of High-Speed Train Induced Aerodynamic Load on Noise Barrier Considering Wind Effect
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2023 (English)In: Building for the Future: Durable, Sustainable, Resilient - Proceedings of the fib Symposium 2023 - Volume 2 / [ed] Alper Ilki, Derya Çavunt, Yavuz Selim Çavunt, Springer, 2023, Vol. 2, p. 332-341Conference paper, Published paper (Refereed)
Abstract [en]

Along the high-speed railway lines, the noise barriers need to be installed to protect nearby inhabitants from noise pollution caused by the running trains. When a high-speed train passes through the noise barriers, due to the blocking effect of noise barrier on air movement, transient train-induced aerodynamic pressure will increase significantly. Field measurement and computational fluid dynamics (CFD) simulation are main ways to study the train-induced aerodynamic pressure on the noise barriers. Due to the complexity of the environmental conditions in field test, however, it is difficult to take into account the wind effects on measurement results. Based on CFD simulation, in this paper, the aerodynamic effects on noise barrier from high-speed trains was simulated by applying the wind flow in the opposite direction to the train running. Influences of train speed and distance from noise barrier to track centre on such aerodynamic pressure were analysed. In addition, by applying the wind flow perpendicular to the longitudinal of train body, the effect of cross wind on the train-induced aerodynamic pressure was evaluated. Results show that pressure magnitude on the noise barriers increases non-linearly with the train speed. There is good nonlinear relationship between the pressure and the square of the distance to track centre. Cross wind increases the magnitude of positive pressure and makes the duration of high-pressure zone longer and absolute value of negative pressure peak decreases. There is a coupling effect of cross wind effect and train-induced aerodynamic effect on noise barriers. 

Place, publisher, year, edition, pages
Springer, 2023
Series
Lecture Notes in Civil Engineering, ISSN 2366-2557, E-ISSN 2366-2565 ; 350
Keywords
Aerodynamic Pressure, Computational Fluid Dynamics, High-Speed Train, Noise Barrier, Wind Effect
National Category
Vehicle Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-99632 (URN)10.1007/978-3-031-32511-3_36 (DOI)2-s2.0-85164256511 (Scopus ID)978-3-031-32510-6 (ISBN)978-3-031-32511-3 (ISBN)
Conference
International Symposium of the International Federation for Structural Concrete, fib Symposium 2023, Istanbul, Turkey, June 5-7, 2023
Available from: 2023-08-14 Created: 2023-08-14 Last updated: 2023-08-14Bibliographically approved
Liu, D., Wang, C., Gonzalez, J., Enoksson, O., Höjsten, T., Tu, Y., . . . Sas, G. (2023). Numerical simulation of train-induced aerodynamic pressure on railway noise barriers. In: XII International Conference on Structural Dynamics, Delft, Netherlands, July 2-5, 2023.: . Paper presented at XII International Conference on Structural Dynamics, Delft, Netherlands, July 2-5, 2023..
Open this publication in new window or tab >>Numerical simulation of train-induced aerodynamic pressure on railway noise barriers
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2023 (English)In: XII International Conference on Structural Dynamics, Delft, Netherlands, July 2-5, 2023., 2023Conference paper, Published paper (Refereed)
Abstract [en]

Noise barriers built parallel to the railway to reduce noise pollution, will be subjected to strong aerodynamic pressure from high-speed trains and have significant dynamic responses under such pressure. Based on computational fluid dynamics (CFD), a numerical simulation of train-induce aerodynamic pressure on noise barriers was performed. Time-varying pressure and its distribution along height direction of noise barriers were analysed, and the effect of different factors on results, i.e., the distance from noise barriers to track centre and the height of noise barrier, were discussed. Results show that the geometric changes in train nose and tail cause the obvious transient pressure pulse, and the pressure magnitude from nose is higher than that from tail. When the measuring height increases, the pressure gradually decreases, which can be well characterized by a height coefficient equation from Germany DB code. The pressure magnitude increases non-linearly when the distance to track centre decreases. Importantly, the height of noise barrier is also an important factor affecting pressure magnitude on noise barriers and when the height of noise barrier increases, the pressure magnitude gradually increases but tends to be stable at higher heights. An exponential equation can well characterize such effect of height of noise barrier on train-induced aerodynamic pressure.

Keywords
Railway noise barrier, CFD simulation, Aerodynamic pressure, High-speed train
National Category
Civil Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-101565 (URN)
Conference
XII International Conference on Structural Dynamics, Delft, Netherlands, July 2-5, 2023.
Funder
Swedish Transport Administration, BBT-2019-022Swedish Transport Administration, Excellence Area 4
Available from: 2023-10-04 Created: 2023-10-04 Last updated: 2023-10-12
Liu, D., Wang, C., Gonzalez, J., Mensah, R. A., Försth, M., Das, O., . . . Tu, Y. (2022). Correlation between early- and later-age performance indices of early frost-damaged concrete. In: František Wald, Pavel Ryjáček (Ed.), IABSE Symposium Prague 2022: Challenges for Existing and Oncoming Structures - Report, International Association for Bridge and Structural Engineering: . Paper presented at IABSE Symposium Prague 2022: Challenges for Existing and Oncoming Structures, Prague, Czech Republic, May 25-27, 2022 (pp. 934-941). International Association for Bridge and Structural Engineering
Open this publication in new window or tab >>Correlation between early- and later-age performance indices of early frost-damaged concrete
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2022 (English)In: IABSE Symposium Prague 2022: Challenges for Existing and Oncoming Structures - Report, International Association for Bridge and Structural Engineering / [ed] František Wald, Pavel Ryjáček, International Association for Bridge and Structural Engineering, 2022, p. 934-941Conference paper, Published paper (Refereed)
Abstract [en]

Freeze‐thaw cycles can lead to serious damage of early‐age concrete and influence its behaviour at later ages. In this study, the later‐age compressive strength, resistance to chloride penetration and resistance to freeze‐thaw of early frost‐damaged concrete were experimentally studied and the relationship between its early‐ (i.e., strength and resistivity) and later‐age (i.e., strength, chloride ion electric flux and freeze‐thaw durability factor) performance indices were analysed. Results show that the later‐age performance of the concrete subjected to freeze‐thaw cycles at early age was generally worse than that of the control samples, which had not undergone early frost damage. This was especially significant for the concrete subjected to freeze‐thaw cycles before the age of 24 h. The compressive strength after early frost action had a higher linear correlation with the later‐age indices of the concrete than the compressive strength before early frost action. Results also showed that the early‐age resistivity is a good indicator for the later‐age performance of early frost‐damaged concrete if the pre‐curing time before frosting is at least 24 h. 

Place, publisher, year, edition, pages
International Association for Bridge and Structural Engineering, 2022
Keywords
compressive strength, durability, early frost damage, freeze‐thaw cycles, resistivity
National Category
Reliability and Maintenance
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-92199 (URN)10.2749/prague.2022.0934 (DOI)2-s2.0-85133531691 (Scopus ID)
Conference
IABSE Symposium Prague 2022: Challenges for Existing and Oncoming Structures, Prague, Czech Republic, May 25-27, 2022
Note

ISBN for host publication: 978-3-85748-181-9

Available from: 2022-07-19 Created: 2022-07-19 Last updated: 2023-09-05Bibliographically approved
Tu, Y., Shi, P., Liu, D., Wen, R., Yu, Q., Sas, G. & Elfgren, L. (2022). Mechanical properties of calcium silicate hydrate under uniaxial and biaxial strain conditions: a molecular dynamics study. Physical Chemistry, Chemical Physics - PCCP, 24(2), 1156-1166
Open this publication in new window or tab >>Mechanical properties of calcium silicate hydrate under uniaxial and biaxial strain conditions: a molecular dynamics study
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2022 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 24, no 2, p. 1156-1166Article in journal (Refereed) Published
Abstract [en]

Calcium silicate hydrate (C-S-H) is the main hydration product of cementitious materials, often experiencing complex stress conditions in practical applications. Therefore, reactive molecular dynamics methods were used to investigate the mechanical response of the atomistic structure of C-S-H under various uniaxial and biaxial strain conditions. The results of uniaxial simulations show that C-S-H exhibits mechanical anisotropy and tension–compression asymmetry due to its layered atomistic structure. By fitting the stress–strain data, a stress–strain relationship that accurately represents the elastoplasticity of C-S-H was developed. The biaxial yield surface obtained from biaxial simulations was ellipsoidal, again reflecting the anisotropy and asymmetry of C-S-H. Four yield criteria (von Mises, Drucker–Prager, Hill, and Liu–Huang–Stout) were further investigated, and it was found that the Liu–Huang–Stout criterion can effectively capture all the major features of the yield surface. During a uniaxial tensile process in the z direction, multi-crack propagation was observed, which was aggravated and weakened by y direction tensile and compressive strains respectively. The results of chemical bond analyses revealed that, for different strain conditions, the CaW–OS and CaS–OS bonds play different roles in resisting deformation.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2022
National Category
Applied Mechanics
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-88585 (URN)10.1039/d1cp04474e (DOI)000731954700001 ()34931206 (PubMedID)2-s2.0-85123387654 (Scopus ID)
Note

Validerad;2022;Nivå 2;2022-02-08 (johcin);

Funder: National Natural Science Foundation of China (51378104), “One belt, one road” innovation cooperation project under policy guidance plan of Jiangsu Province (BZ2021011)

Available from: 2021-12-28 Created: 2021-12-28 Last updated: 2022-06-01Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-2668-1329

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