4 results on '"Lin, Xixian"'
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2. Research progress on volatile organic compound emission monitoring technology and equipment in port areas.
- Author
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FANG Mingzhong, LIN Xixian, HU Shubi, JU Tuo, FANG Yangdan, and LU Lichao
- Subjects
EMISSIONS (Air pollution) ,VOLATILE organic compounds ,AIR pollution control ,AIR pollution ,AIR pollution monitoring ,POLLUTION control equipment ,PHOTOCHEMICAL smog - Abstract
[Objective] Air pollution is closely associated with humans and is of major concern. Volatile organic compounds (VOCs) are included in China's "14th Five-Year Plan" air pollution indicators in 2021, becoming one of the important tasks to control air pollution. VOCs adversely affect the environment, causing urban and photochemical smog, leading to physical and mental health hazards for residents. Investigating the emission characteristics of VOCs can offer a scientific basis for the efficient control and emission reduction of VOCs. Local scholars have been actively participating in research and development of air pollution reduction technologies and have established a national emission inventory for application to national mobile source emission reduction work. With the progress of research on land-based stationary sources and road vehicle emissions, VOC emissions in urban functional areas have been gradually and effectively controlled. Although the development of the water transport industry has brought huge economic benefits, it has also worsened VOC emissions in the surrounding port areas. Performing research on VOC emissions in port areas is the groundwork for attaining efficient VOC control. [Methods] In this work, the sources of atmospheric VOC pollutants in ports are listed: port transportation vehicles, port machinery, and dry/liquid bulk terminals. The characteristic pollutants are alkanes, olefins, and aromatic hydrocarbons. Currently, local scholars are primarily concerned about VOC emissions from key ports and hub waterways along the eastern coast, while foreign scholars are concerned about port emission monitoring and have successively established relevant actions for port emission restrictions. Moreover, mobile sources of VOCs from fuel-fuel-powered ship power units during port operations are examined. Many computational models have been employed to simulate the diffusion process of urban VOCs and analyze the main VOC components that influence ozone formation, such as the Gaussian diffusion model and the HYSPLIT model. [Results] In this work, we analyze the classification of VOC emission monitoring technologies, as well as their application status and characteristics. We also demonstrate how air pollution monitoring equipment can be used in the port area to identify pollution sources and rapidly detect VOCs, offering strong technical support for studying VOC emission characteristics in the port area. Several large-scale and high-precision monitoring methods are not appropriate for air pollution monitoring in port areas, making it difficult to acquire basic information and activity level data of ships, leading to insufficient accumulation of VOC emission data in port areas and the need to expand monitoring coverage. [Conclusions] Most of the emission studies of ships in port areas are based on the fuel consumption method, which cannot be systematically analyzed for ship emission characteristics, and numerous air pollution diffusion analysis models have not been implemented in air pollution emission studies in port areas. Hence, based on the characteristics of VOC emissions in port areas, selecting and improving the adaptive calculation model is urgently needed. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. A high-power PCCM LED driver based on GaN eHEMT with hybrid dimming modes
- Author
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Yimeng Zhang, Yuming Zhang, Guangjian Rong, and Lin Xixian
- Subjects
Computer science ,business.industry ,020209 energy ,020208 electrical & electronic engineering ,0202 electrical engineering, electronic engineering, information engineering ,Electrical engineering ,Led driver ,02 engineering and technology ,Electrical and Electronic Engineering ,business ,Industrial and Manufacturing Engineering ,Power (physics) - Abstract
Purpose The purpose of this study is to design a more flexible and larger range of the dimming circuit that achieves the independence of multiple LED strings drive and can time-multiplex the power circuit. Design/methodology/approach The state-space method is used to model the BUCK circuit working in Pseudo continuous conduction mode, analyze the frequency characteristics of the system transfer function and design the compensation network. Build a simulation platform on the Orcad PSPICE platform and verify the function of the designed circuit through the simulation results. Use Altium Designer 16 to draw the printed circuit board, complete the welding of various components and use the oscilloscope, direct current (DC) power supply and a signal generator to verify the circuit function. Findings A prototype of the proposed LED driver is fabricated and tested. The measurement results show that the switching frequency can be increased to 1 MHz, Power inductance is 2.2 µH, which is smaller than current research. The dimming ratio can be set from 10% to 100%. The proposed LED driver can output more than 48 W and achieve a peak conversion efficiency of 91%. Originality/value The proposed LED driver adopts pulse width modulation (PWM) dimming at a lower dimming ratio and adopts DC dimming at a larger dimming ratio to realize switching PWM dimming to analog dimming. The control strategy can be more precise and have a wide range of dimming.
- Published
- 2021
4. A high-power PCCM LED driver based on GaN eHEMT with hybrid dimming modes
- Author
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Lin, Xixian, primary, Zhang, Yuming, additional, Zhang, Yimeng, additional, and Rong, Guangjian, additional
- Published
- 2021
- Full Text
- View/download PDF
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