Variation characteristics of ultraviolet radiation derived from measurement and reconstruction in Beijing, China

Tellus B ◽  
2010 ◽  
Vol 62 (2) ◽  
Author(s):  
Bo Hu ◽  
Yuesi Wang ◽  
Guangren Liu
Keyword(s):  
Ultraviolet Radiation ◽  
Variation Characteristics ◽  
Beijing China

scholarly journals Primary Air Pollutants Emissions Variation Characteristics and Future Control Strategies for Transportation Sector in Beijing, China

2020 ◽  
Vol 12 (10) ◽  
pp. 4111 ◽  
Author(s):  
Yifeng Xue ◽  
Xizi Cao ◽  
Yi Ai ◽  
Kangli Xu ◽  
Yichen Zhang
Keyword(s):  
Air Pollutants ◽  
Freight Transportation ◽  
Air Pollutant ◽  
Pollutant Emissions ◽  
Motor Vehicles ◽  
Railway Transportation ◽  
Road Transportation ◽  
Transportation Sector ◽  
Variation Characteristics ◽  
Beijing China

Air pollutant emissions from vehicles, railways, and aircraft for freight and passenger transportation are major sources of air pollution, and strongly impact the air quality of Beijing, China. To better understand the variation characteristics of these emissions, we used the emission factor method to quantitatively determine the air pollutant emissions from the transportation sector. The emission intensity of different modes of transportation was estimated, and measures are proposed to prevent and control air pollutants emitted from the transportation sector. The results showed that air pollutant emissions from the transportation sector have been decreasing year by year as a result of the reduction in emissions from motor vehicles, benefiting from the structural adjustment of motor vehicles. A comparison of the emission intensity of primary air pollutants from different modes of transportation showed that the emission level of railway transportation was much lower than that of road transportation. However, Beijing relies heavily on road transportation, with road freight transportation accounting for 96% of freight transportation, whereas the proportion of railway transportation was low. Primary air pollutants from the transportation sector contributed significantly to the total emissions in Beijing. The proportion of NOX emissions increased from 54% in 2013 to 58% in 2018. To reduce air pollutant emissions from the transportation sector, further adjustments and optimization of the structure of transportation in Beijing are needed. As for the control of motor vehicle pollutant emissions, vehicle composition must be adjusted and the development of clean energy must be promoted, as well as the replacement of diesel vehicles with electric vehicles for passenger and freight transportation.

Applications of Photoelectron Microscopy

1976 ◽  
Vol 34 ◽  
pp. 506-507
Author(s):  
William J. Baxter
Keyword(s):  
Electron Microscopy ◽  
Thermal Decomposition ◽  
Chemical Composition ◽  
Ultraviolet Radiation ◽  
Thin Layer ◽  
Edge Effects ◽  
Electron Optics ◽  
Surface Layers ◽  
Crystalline Orientation ◽  
Fluorescent Screen

In this form of electron microscopy, photoelectrons emitted from a metal by ultraviolet radiation are accelerated and imaged onto a fluorescent screen by conventional electron optics. image contrast is determined by spatial variations in the intensity of the photoemission. The dominant source of contrast is due to changes in the photoelectric work function, between surfaces of different crystalline orientation, or different chemical composition. Topographical variations produce a relatively weak contrast due to shadowing and edge effects.Since the photoelectrons originate from the surface layers (e.g. ∼5-10 nm for metals), photoelectron microscopy is surface sensitive. Thus to see the microstructure of a metal the thin layer (∼3 nm) of surface oxide must be removed, either by ion bombardment or by thermal decomposition in the vacuum of the microscope.

803: Interactions Between Ultraviolet Radiation and Polymorphisms in the Vitamin D Receptor Gene Mediate Prostate Cancer Susceptibility

2006 ◽  
Vol 175 (4S) ◽  
pp. 260-260
Author(s):  
Nicholas J. Rukin ◽  
Samuel J. Moon ◽  
Dhaval Bodiwala ◽  
Christopher J. Luscombe ◽  
Mark F. Saxby ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Vitamin D ◽  
Ultraviolet Radiation ◽  
Vitamin D Receptor ◽  
Cancer Susceptibility ◽  
Receptor Gene ◽  
Vitamin D Receptor Gene ◽  
Prostate Cancer Susceptibility
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