Views on Three Milestones in the Construction of Beijing City

2014 ◽  
pp. 49-59
Author(s):  
Renzhi Hou
Keyword(s):  
Beijing City

scholarly journals Application of genetic programming to modeling pipe failures in water distribution systems

2010 ◽  
Vol 13 (3) ◽  
pp. 419-428 ◽  
Author(s):  
Qiang Xu ◽  
Qiuwen Chen ◽  
Weifeng Li
Keyword(s):  
Genetic Programming ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Pipe Failure ◽  
Beijing City ◽  
Failure Data ◽  
Processing Strategies ◽  
Gis Data ◽  
Failure Models

The water loss from a water distribution system is a serious problem for many cities, which incurs enormous economic and social loss. However, the economic and human resource costs to exactly locate the leakage are extraordinarily high. Thus, reliable and robust pipe failure models are demanded to assess a pipe's propensity to fail. Beijing City was selected as the case study area and the pipe failure data for 19 years (1987–2005) were analyzed. Three different kinds of methods were applied to build pipe failure models. First, a statistical model was built, which discovered that the ages of leakage pipes followed the Weibull distribution. Then, two other models were developed using genetic programming (GP) with different data pre-processing strategies. The three models were compared thereafter and the best model was applied to assess the criticality of all the pipe segments of the entire water supply network in Beijing City based on GIS data.

Building a Memory Map to Reconstruct an Urban Memory: The Case of the Beijing City Gates

2020 ◽  
Vol 69 (1) ◽  
pp. 76-100
Author(s):  
Li Niu ◽  
Lichao Liu ◽  
Chenxiang Gao ◽  
Xiaoshuang Jia
Keyword(s):  
Beijing City ◽  
City Gates

scholarly journals Impact of crop field burning and mountains on heavy haze in the North China Plain: A case study

2016 ◽  
Author(s):  
X. Long ◽  
X. X. Tie ◽  
J. J. Cao ◽  
R. J. Huang ◽  
T. Feng ◽  
...  
Keyword(s):  
Air Pollution ◽  
North China Plain ◽  
North China ◽  
Wind Condition ◽  
Beijing City ◽  
The North ◽  
The North China Plain ◽  
Crop Field ◽  
The Impact ◽  
Field Burning

Abstract. Crop field burning (CFB) has important effects on air pollution in China, but it is seldom quantified and reported in a regional scale, which is of great importance for the control strategies of CFB in China, especially in the North China Plain (NCP). With the provincial statistical data and open crop fires captured by satellite (MODIS), we extracted a detailed emission inventory of CFB during a heavy haze event from 6th to 12th October 2014. A regional dynamical and chemical model (WRF-Chem) was applied to investigate the impact of CFB on air pollution in NCP. The model simulations were compared with the in situ measurements of PM2.5 (particular matter with radius less than 2.5 μm) concentrations. The model evaluation shows that the correlation coefficients (R) between measured and calculated values exceeds 0.80 and absolute normalized mean bias (NMB) is no more than 14 %. In addition, the simulated meteorological parameters such as winds and planetary boundary layer height (PBLH) are also in good agreement with observations. The model was intensive used to study (1) the impacts of CFB and (2) the effect of mountains on regional air quality. The results show that the CFB occurred in southern NCP (SNCP) had significant effect on PM2.5 concentrations locally, causing a maximum of 35 % PM2.5 increase in SNCP. Because of south wind condition, the CFB pollution plume is subjective a long transport to northern NCP (NNCP-with several mega cities, including Beijing of the capital city in China), where there are no significant CFB occurrences, causing a maximum of 32 % PM2.5 increase in NNCP. As a result, the heavy haze in Beijing is enhanced by the CFB occurred in SNCP. Further more, there are two major mountains located in the western and northern NCP. Under the south wind condition, these mountains play important roles in enhancing the PM2.5 pollution in NNCP through the blocking and guiding effects. This study suggests that the PM2.5 emissions in SNCP region should be significantly limited in order to reduce the occurrences of heavy haze events in NNCP region, including the Beijing City.

scholarly journals Regimes of rainfall preceding regional rainfall events over the plain of Beijing City

2018 ◽  
Vol 38 (13) ◽  
pp. 4979-4989 ◽  
Author(s):  
Weihua Yuan ◽  
Hang Xu ◽  
Rucong Yu ◽  
Jian Li ◽  
Yingxin Zhang ◽  
...  
Keyword(s):  
Beijing City ◽  
Rainfall Events ◽  
Regional Rainfall

Holopogon pekinensis (Orchidaceae), a new heteromycotrophic species from Northern China

Phytotaxa ◽  
2017 ◽  
Vol 326 (2) ◽  
pp. 151
Author(s):  
XIAN-YUN MU ◽  
BING LIU ◽  
YI-XUAN ZHU ◽  
LING TONG ◽  
QIN-WEN LIN ◽  
...  
Keyword(s):  
New Species ◽  
Endangered Species ◽  
Conservation Status ◽  
Far East ◽  
Northern China ◽  
Identification Key ◽  
Beijing City ◽  
East Russia ◽  
Light Green

Holopogon pekinensis, a new heteromycotrophic orchid from Beijing City, China, is described and illustrated. This new species is morphologically similar to an endangered species endemic to Far East Russia, Holopogon ussuriensis Komarov & Nevski, but differs in having green flowers (vs white) and light green pubescence (vs red). Its conservation status and an identification key to Holopogon are provided.

scholarly journals Air Quality Improvement in a Megacity: Implications from 2015 Beijing Parade Blue Pollution-Control Actions

2016 ◽  
Author(s):  
Wen Xu ◽  
Wei Song ◽  
Yangyang Zhang ◽  
Xuejun Liu ◽  
Lin Zhang ◽  
...  
Keyword(s):  
Quality Improvement ◽  
Air Quality ◽  
Control Period ◽  
Emission Control ◽  
Monitoring Network ◽  
Control Measures ◽  
Integrated Analysis ◽  
Beijing City ◽  
Air Quality Improvement ◽  
Emission Control Measures

Abstract. The implementation of strict emission control measures in Beijing and surrounding regions during the 2015 China Victory Day Parade provided a valuable opportunity to investigate related air quality improvements in a megacity. We measured NH3, NO2 and PM2.5 at multiple sites in and outside Beijing and summarized concentrations of PM2.5, PM10, NO2, SO2 and CO in 291 cities across China from a national urban air quality monitoring network between August and September 2015. Consistently significant reductions of 12–35 % for NH3 and 33–59 % for NO2 in different areas of Beijing city during the emission control period (referred to as the Parade Blue period) were observed compared with measurements in the pre- and post-Parade Blue periods without emission controls. Average NH3 and NO2 concentrations at sites near traffic were strongly correlated and showed positive and significant responses to traffic reduction measures, suggesting that traffic is an important source of both NH3 and NOx in urban Beijing. Daily concentrations of PM2.5 and secondary inorganic aerosol (sulfate, ammonium, and nitrate) at the urban and rural sites both decreased during the Parade Blue period. Concentrations of PM2.5, PM10, NO2, SO2 and CO from the national city-monitoring network showed the largest decrease (34–72 %) in Beijing, a smaller decrease (1–32 %) in North China (excluding Beijing), and an increase (6–16 %) in other regions of China during the emission control period. Integrated analysis of modeling and monitoring results demonstrated that emission control measures made a major contribution to air quality improvement in Beijing compared with a minor contribution from favorable meteorological conditions during the Parade Blue period. These results show that controls of secondary aerosol precursors (NH3, SO2 and NOx) locally and regionally are key to curbing air pollution in Beijing and probably in other mega cities worldwide.

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