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10 results on '"W. Y. Xu"'

2. Surface Temperature Prediction of Asphalt Pavement Based on GBDT

Author

H. J. Hong, X. Qiu, W. Y Xu, N. N. Li, and Z. H. Zhang

Subjects
Surface (mathematics), Asphalt pavement, Computer science, Geotechnical engineering
Abstract

Asphalt is a temperature sensitive material, distribution characteristics and vary rules of asphalt pavement temperature have an important impact on the bearing capacity and performance of pavement, which is a concern of domestic and foreign researchers. The objective of this study was to explore the correlation between pavement temperature of asphalt pavements and meteorological factors and implement an accurate trend prediction of the asphalt pavement temperature. First, errors and missing data in the meteorological dataset were cleaned. Then, the three kinds of temperature prediction models of asphalt pavements in winter were established by Gradient Boosting Decision Tree (GBDT), Random Forest (RF) and Linear Regression (LR). The results indicate that GBDT would perform an excellent ability on prediction. The mean-square-error of the GBDT predicting results has a lower value of 1.5 when compared with the Random Forest and Linear Regression owing to the high robustness and the good generalization ability, which reflects the GBDT model has a good applicability in the field of prediction. The research would serve as a technical support for the machine learning algorithms applied in the field of the application of prediction problems.

Published
2020

3. Study on Temperature Related Factors of Asphalt Pavement Based on APRIORI

Author

H. J. Hong, W. Y. Lin, W. Y. Xu, Z. H. Zhang, and X. Qiu

Subjects
Related factors, Asphalt pavement, Environmental science, Geotechnical engineering
Abstract

Asphalt is a typical temperature-sensitive material. In order to explore the correlation between surface temperature of asphalt pavements and meteorological factors, the association rules mining algorithm (Apriori) was applied to identify the key factors affecting the surface temperature of asphalt pavement. Firstly, errors and missing data in the meteorological dataset were cleaned. Then, Apriori was applied to identify the key factors affecting the asphalt pavement temperature. The results indicate that Apriori would perform an excellent ability to analyze the correlation rules between meteorological factors with the minimum confidence of 0.8 and the key meteorological factors which affect the temperature change of asphalt pavements are excavated including air temperature, air pressure, dew point temperature and relative humidity. The research would serve as a technical support for the machine learning algorithms applied in the field of the association rule analysis.

Published
2020

4. Preparation of Ga 2 O 3 thin film solar-blind photodetectors based on mixed-phase structure by pulsed laser deposition

Author

S Han, Y X Zeng, P J Cao, F Jia, W Y Xu, Y M Lu, Wenjun Liu, Chong Li, X K Liu, Deyong Zhu, and Xi Chen

Subjects
Aluminium oxides, Surface coating, Materials science, business.industry, General Physics and Astronomy, Optoelectronics, Deposition (phase transition), Photodetector, Electric potential, Irradiation, Thin film, business, Pulsed laser deposition
Published
2019

5. High signal/noise ratio deep UV detector with maximum response at 230 nm based on mix-phase MgZnO deposited under high laser energy condition

Author

F. Jia, W. Y. Xu, D. L. Zhu, Xinke Liu, S. Han, Wenjun Liu, Y. M. Lu, S. R. Hu, P. J. Cao, and Y. X. Zeng

Subjects
010302 applied physics, Materials science, High signal intensity, Uv detector, business.industry, Phase (waves), General Physics and Astronomy, 02 engineering and technology, 021001 nanoscience & nanotechnology, Laser, 01 natural sciences, law.invention, Optics, law, 0103 physical sciences, Energy condition, 0210 nano-technology, business, Noise (radio)
Published
2018

8. Preparation of Ga2O3 thin film solar-blind photodetectors based on mixed-phase structure by pulsed laser deposition.

Author

Y M Lu, C Li, X H Chen, S Han, P J Cao, F Jia, Y X Zeng, X K Liu, W Y Xu, W J Liu, and D L Zhu

Subjects
GALLIUM compounds, METALLIC thin films, PHOTODETECTORS, PHASE transitions, PULSED laser deposition
Abstract

Gallium oxide (Ga2O3) thin films were deposited on a-Al2O3 ( substrates by pulsed laser deposition (PLD) with different oxygen pressures at 650 °C. By reducing the oxygen pressure, mixed-phase Ga2O3 films with α and β phases can be obtained, and on the basis of this, mixed-phase Ga2O3 thin film solar-blind photodetectors (SBPDs) were prepared. Comparing the responsivities of the mixed-phase Ga2O3 SBPDs and the single β-Ga2O3 SBPDs at a bias voltage of 25 V, it is found that the former has a maximum responsivity of approximately 12 A/W, which is approximately two orders of magnitude larger than that of the latter. This result shows that the mixed-phase structure of Ga2O3 thin films can be used to prepare high-responsivity SBPDs. Moreover, the cause of this phenomenon was investigated, which will provide a feasible way to improve the responsivity of Ga2O3 thin film SBPDs. [ABSTRACT FROM AUTHOR]

Published
2019
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9. High signal/noise ratio deep UV detector with maximum response at 230 nm based on mix-phase MgZnO deposited under high laser energy condition.

Author

S. Han, S. R. Hu, P. J. Cao, W. J. Liu, Y. X. Zeng, F. Jia, W. Y. Xu, X. K. Liu, D. L. Zhu, and Y. M. Lu

Abstract

A Mix-phase MgZnO thin film was fabricated on the c-plane sapphire substrate (Mg0.4Zn0.6O target) under high laser energy density condition by the PLD method. The internal quantum efficiency of the detector based on the mix-phase MgZnO thin film at 230 nm deep UV light reached 86% at 40 V bias voltage. And the Iuv(230 nm)/Idark ratio of the MgZnO detector reached 864 at 40 V bias voltage, which is mainly caused by both the higher internal gain of the detector at deep UV light and its smaller Idark. The high internal gain of the detector is mainly due to the higher density of interfaces between the different structure of MgZnO grains in the mix-phase MgZnO thin film, which is caused by the higher laser energy density deposition condition certified by contrast experiments. The small Idark of the detector is mainly caused by the higher barriers in the mix-phase MgZnO thin film and more cubic MgZnO in the mix-phase MgZnO thin film, and higher laser energy density deposition condition and O-rich c-plane sapphire substrate surface are key factors, which also agree with the contrast experiments results. So when the mix-phase MgZnO thin film that is constituted by both a small number of narrower band gap hexagonal MgZnO and a large number of wide band gap cubic MgZnO is used in the deep UV detector, and the difference in band gaps between different structures of MgZnO is relatively higher, a higher signal/noise ratio of the device at 230 nm deep UV light is gained, which is meaningful for developing high-performance deep UV detection technology. [ABSTRACT FROM AUTHOR]

Published
2018
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