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681.
Roads and buildings are considered as primary causes of rural landscape changes. In this study, linear regression models were used to analyze the dynamic influences of environmental factors and variables on roads and rural buildings from 1979 to 2005 in Dongzhi Yuan (tableland) of the Loess Plateau, China. The relationship between roads and rural buildings and their effects on Dongzhi Yuan are discussed also. The results showed that three environmental factors (topography, land cover, and development level) explained roads better than rural buildings referring densities and patterns. The environmental variables significantly related to roads have decreased, whereas those related to rural buildings have increased over time. Among these significant variables, percent of farmland mostly determined the densities and patterns of both roads and rural buildings. There was significant correlation between roads and rural buildings in terms of density and pattern. In addition, roads and rural buildings have increased greatly in gully areas of this region. Therefore, more attention should be paid to planning of roads and rural buildings in Dongzhi Yuan. 相似文献
682.
Jing Ge Dongmei Qin Yuzhen Zhao Canping Pan Shuren Jiang Fengmao Liu 《Environmental monitoring and assessment》2010,162(1-4):219-224
The analytical method of famoxadone residue and its dissipation in grape and soil were investigated. Famoxadone (68.75% water-dispersible granule) was applied at two dosages (1.25 and 2.5 g l???1). Soil and grape samples were collected at intervals and analyzed for famoxadone residues. The results showed that the degradation rate of famoxadone in grape and soil were similar, and their dynamics could be described by C?=?1.1738e ???0.0562t with correlation coefficient r?=?0.9044 in grape and C?=?5.6565e ???0.0515t with r?=?0.9620 in soil, respectively. Half-lives were 12.3 and 13.5 days in grape and soil, respectively. The results indicated that at harvest time, the residues of famoxadone in grape were well below the EU’s maximum residue level (2 mg kg???1) and was safe to apply in grape. 相似文献
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二级SBR法处理高浓度氨氮化工废水研究 总被引:6,自引:0,他引:6
用直接活性污泥法完成了各反应器的污泥驯化启动。二级SBR工艺主要由硝化SBR和反硝化SBR反应器构成,其中硝化SBR反应器采用悬浮生长法和固定生物膜法两种工艺作对比试验。结果表明,后者较前者具有更大的NH3-N容积负荷,最大可达766.54mgL^-1d^-1;而且能节省碱的消耗量11.0%~38.7%和反硝化所需碳源量为30%~40%。在tHR为24h的条件下,二级SBR法能处理ρIn(NH3- 相似文献
685.
Minzhong Wang Wenshou Wei Zheng Ruan Qing He Runsheng Ge 《Environmental monitoring and assessment》2013,185(6):4819-4834
The Urumqi Institute of Desert Meteorology of the China Meteorological Administration carried out an atmospheric scientific experiment to detect dust weather using a wind-profiling radar in the hinterland of the Taklimakan Desert in April 2010. Based on the wind-profiling data obtained from this experiment, this paper seeks to (a) analyze the characteristics of the horizontal wind field and vertical velocity of a breaking dust weather in a desert hinterland; (b) calculate and give the radar echo intensity and vertical distribution of a dust storm, blowing sand, and floating dust weather; and (c) discuss the atmosphere dust counts/concentration derived from the wind-profiling radar data. Studies show that: (a) A wind-profiling radar is an upper-air atmospheric remote sensing system that effectively detects and monitors dust. It captures the beginning and ending of a dust weather process as well as monitors the sand and dust being transported in the air in terms of height, thickness, and vertical intensity. (b) The echo intensity of a blowing sand and dust storm weather episode in Taklimakan is about ?1~10 dBZ while that of floating dust ?1~?15 dBZ, indicating that the dust echo intensity is significantly weaker than that of precipitation but stronger than that of clear air. (c) The vertical shear of horizontal wind and the maintenance of low-level east wind are usually dynamic factors causing a dust weather process in Taklimakan. The moment that the low-level horizontal wind field finds a shear over time, it often coincides with the onset of a sand blowing and dust storm weather process. (d) When a blowing sand or dust storm weather event occurs, the atmospheric vertical velocity tends to be of upward motion. This vertical upward movement of the atmosphere supported with a fast horizontal wind and a dry underlying surface carries dust particles from the ground up to the air to form blown sand or a dust storm. 相似文献
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Greening China Naturally 总被引:2,自引:0,他引:2
Cao S Sun G Zhang Z Chen L Feng Q Fu B McNulty S Shankman D Tang J Wang Y Wei X 《Ambio》2011,40(7):828-831
China leads the world in afforestation, and is one of the few countries whose forested area is increasing. However, this massive "greening" effort has been less effective than expected; afforestation has sometimes produced unintended environmental, ecological, and socioeconomic consequences, and has failed to achieve the desired ecological benefits. Where afforestation has succeeded, the approach was tailored to local environmental conditions. Using the right plant species or species composition for the site and considering alternatives such as grassland restoration have been important success factors. To expand this success, government policy should shift from a forest-based approach to a results-based approach. In addition, long-term monitoring must be implemented to provide the data needed to develop a cost-effective, scientifically informed restoration policy. 相似文献
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Projection of hazard changes in climate extremes is critical to assessing the potential impacts of climate change on human and natural systems. Using simulations of providing regional climates for impacts studies, five indicators (rainstorm days, maximum 3-day precipitation, elevation, gradient and distance from river or lake) were selected to project the spatial patterns of flood hazard over Yangtze River Basin for the baseline period (1961– 1990) and future (2011–2100) under SRES B2 scenario. The results ... 相似文献