Time filter

Source Type

Chang H.,Tsinghua University | Wu Z.-X.,Tsinghua University | Guo S.-Y.,The Environmental Protection Information Center | Yang X.-T.,Tsinghua University
Annals of Nuclear Energy | Year: 2015

An optimized process for tritium-containing waste water collection of Higherature Gas-cooled Reactor (HTGR) was developed and experimentally verified using the 10 MW Higherature Gas-cooled Reactor-test module (HTR-10). Compared with the previous process, an auxiliary molecular sieve bed was added in helium purification regeneration system and new operation process was proposed to collect tritium-containing waste water. In this paper, the optimized process and verification experiment were presented in detail. In commissioning experiment of the improved HTR-10, a large quantity of high-dose tritium-containing waste water was successfully collected in the water separator of helium purification regeneration system, with the specific activity being 6.1 × 109 Bq/L. The verification experiment confirms that the optimized process is effective and reliable for the demonstration plant design of High Temperature Gas-cooled Reactor-Pebble bed module (HTR-PM) to avoid the large emission of detrimentally radioactive waste water to the environment. © 2015 Elsevier Ltd. All rights reserved. Source

Xu L.,Beijing Normal University | Yin H.,Beijing Normal University | Li Z.,Beijing Normal University | Li S.,The Environmental Protection Information Center
International Journal of Environmental Research and Public Health | Year: 2014

As the land ecosystem provides the necessary basic material resources for human development, land ecological security (LES) plays an increasingly important role in sustainable development. Given the degradation of land ecological security under rapid urbanization and the urgent LES requirements of urban populations, a comprehensive evaluation method, named Double Land Ecological Security (DLES), has been introduced with the city of Guangzhou, China, as a case study, which evaluates the LES in regional and unit scales for reasonable and specific urban planning. In the evaluation process with this method, we have combined the material security with the spiritual security that is inevitably associated with LES. Some new coefficients of land-security supply/demand distribution and technology contribution for LES evaluation have also been introduced for different spatial scales, including the regional and the unit scales. The results for Guangzhou indicated that, temporally, the LES supply indices were 0.77, 0.84 and 0.77 in 2000, 2006 and 2009 respectively, while LES demand indices for the city increased in 2000, 2006 and 2009 from 0.57 to 0.95, which made the LES level decreased slowly in this period. Spatially, at the regional scale, the urban land ecological security (ULES) level decreased from 0.2 (marginal security) to −0.18 (marginal insecurity) as a whole, in unit scale, areas in the north and in parts of the east were relatively secure and the security area was shrinking with time, but the central and southern areas turned to be marginal insecurity, especially in 2006 and 2009. This study proposes that DLES evaluation should be conducted for targeted and efficient urban planning and management, which can reflect the LES level of study area in general and in detail. © 2014 by the authors; licensee MDPI, Basel, Switzerland. Source

Xu L.Y.,Beijing Normal University | Xie X.D.,Beijing Normal University | Li S.,The Environmental Protection Information Center
Environmental Pollution | Year: 2013

This study combines the methods of observation statistics and remote sensing retrieval, using remote sensing information including the urban heat island (UHI) intensity index, the normalized difference vegetation index (NDVI), the normalized difference water index (NDWI), and the difference vegetation index (DVI) to analyze the correlation between the urban heat island effect and the spatial and temporal concentration distributions of atmospheric particulates in Beijing. The analysis establishes (1) a direct correlation between UHI and DVI; (2) an indirect correlation among UHI, NDWI and DVI; and (3) an indirect correlation among UHI, NDVI, and DVI. The results proved the existence of three correlation types with regional and seasonal effects and revealed an interesting correlation between UHI and DVI, that is, if UHI is below 0.1, then DVI increases with the increase in UHI, and vice versa. Also, DVI changes more with UHI in the two middle zones of Beijing. © 2013 Elsevier Ltd. All rights reserved. Source

Huang Z.,Beihang University | Wang L.,Beihang University | Wang L.,The Environmental Protection Information Center | Liang X.,Beihang University
Shuju Caiji Yu Chuli/Journal of Data Acquisition and Processing | Year: 2015

Satellite navigation message is an indispensable element for satellite navigation system functioning normally and precisely. The design and evaluation of the message is critical for constructing a satellite navigation system. The development history and performance discrepancy regarding extant different GNSS are analyzed in message content, message structure, and message broadcast way. In addition, the technical problems of design and evaluation in current navigation message are proposed. Furthermore, the relevant technologies and trends are predicted and prospected. ©, 2015, Journal of Data Acquisition and Processing. All right reserved. Source

Zhang B.,The Environmental Protection Information Center
Advanced Materials Research | Year: 2014

China is meeting many environmental challenges that threaten food safety and security but there are actions China may implement to improve this situation. Current impediments include continued population increase, rapid urbanization, and decrease in arable lands, water pollution and climate change. China should control the population, improve irrigation techniques, fight against water pollution and invest on education to facilitate a major transition in the development mode and strive for more sustainable consumption of natural resources. These actions will ensure China's self-sufficiency and prosperity. © (2014) Trans Tech Publications, Switzerland. Source

Discover hidden collaborations