Papers by Author: Na Li

Abstract: As the important part of expressway, the construction technology of asphalt pavement will contribute to the production of greenhouse gases and other volatile organic compounds (VOCs), which has a significant impact on the environment. In order to further analyze the composition, distribution and release of VOCs during asphalt pavement construction, the VOCs emission during paving and rolling were measured through field investigation and sampling. The results show that there are approximately 100 kinds of VOCs substances detected due to the complex organic component of asphalt binder, which is a critical factor to influence the VOCs emission during asphalt pavement construction. During the paving process, the largest VOCs release is 1015.05 ug/m³. With the increase of rolling times, the pavement temperature gradually decrease, and the VOCs emission drops to 266.73 ug/m³. The content of the 10 kinds of substances with the highest concentration accounts for more than 50% of the total VOCs content, in which the proportion of aliphatic hydrocarbons (ALH) and oxygenated hydrocarbon (O-HYD) of the paving process are the highest, while the proportion of aromatic hydrocarbons (ARH) is dominated in the rolling process. The results are vulnerable to the external environment, especially at lower emission level. The relevant research results have certain guiding significance for the control and treatment of harmful gas emission in the construction process of asphalt pavement.

Abstract: Transparent conducting antimony doped tin oxide (ATO) films have been prepared on quartz glass substrate by pulsed laser deposition (PLD) method which is distinctive to maintain the elemental components between the targets and the obtained thin films under optimal conditions. The effect of annealing temperature on the electrical and optical properties of the ATO thin films has been discussed. The annealing treatments have been often employed to reduce the defects and enlarge the grain size for more desirable crystalline structure. As the annealing temperature increases, the ATO thin films exhibited a slightly enhanced crystallinity. Furthermore, annealing treatment can promote both conductivity and transmittance significantly, especially for conductivity. The X-ray photoelectron spectroscopy is used to explore the variation of Sb5+/Sb3+ ratio against the annealing temperature. The optimal resistivity is 2.7×10-3 Ω cm and the average transmittance is about 92% at annealing temperature of 550 oC.

Abstract: Transparent Conducting Antimony Doped Tin Oxide (ATO) Films Have Been Prepared on Quartz Substrate by Pulsed Laser Deposition (PLD) Technology. Despite of Extensive Researches of ATO Films Prepared by other Methods, the Study of PLD Technology Is Relatively few. PLD Technology Is Distinctive to Maintain the Elemental Components between the Targets and the Obtained Thin Flms under Optimal Conditions Contributing to Precise Control of Composition and Doping Ratio of ATO Films. The Effect of Sb₂O₃ Doping on the Electrical and Optical Properties of the ATO Films Was Investigated with Various Sb₂O₃ Doping Ratio (mol%) as 2, 4, 6, 8, 10 at 500 °C in an Oxygen Pressure of 8 Pa. The Results Suggest that the Electrical Resistivity Is Firstly Decreased and then Increased with the Increase of Sb₂O₃ Doping Ratio. When the Sb₂O₃ Doping Ratio Is about 6 mol%, the Optimal Electrical Resistivity Is 3.5×10-3 Ω.cm and the Average Optical Transmittance Is 83.1%. It Is Significant to Clarify the Impact Mechanism of Sb₂O₃ Doping Ratio to Get the Best Electrical and Optical Physical Properties. it Is Supposed that the Carrier Concentration Dominates at a Low Sb₂O₃ Doing Ratio while a Scattering Effect Is Performed at a High Sb₂O₃ Doing Ratio.