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291.
Overuse of land resources has increasingly contributed to environmental crises in China. To mitigate widespread land degradation, actions have been taken to maintain and restore the ecological environment through efforts such as ecological engineering. By analyzing trends in land use, the impact and effectiveness of ecological engineering can be determined. In this study, such changes in Huanjiang County in China were considered. In the early 1990s, an eco-immigration policy and “returning farmland to forest program” were implemented in the county, drastically impacting land use. Land use/land cover changes were detected and analyzed using remote sensing data recorded over 4 years (1995, 2000, 2005, and 2010). Land transfer flow and the rate of land use change elucidated the extent of changes, while nuclear density analysis indicated spatial agglomeration. The results indicate that, over a period of 15 years, farmland area increased, while forest area decreased initially before subsequently increasing. From 1995 to 2000, the highest transfer flow was observed in the grassland to farmland conversion (79.34%). From 2000 to 2005, the transfer flow of conversions was the highest for forest to farmland (56.79%). Land use changes were not prominent from 2005 to 2010. Direct drivers of land use change exert obvious impacts on land use, and indirect drivers impact direct drivers that are then channeled through direct anthropogenic drivers (e.g., land use policies). We found that ecological engineering has a very significant impact on land use change, and that impact varies from region to region.  相似文献   
292.
基于MOD16的安徽省地表蒸散量时空变化特征   总被引:2,自引:0,他引:2  
安徽省是我国的农业大省,其水资源的管理和利用直接影响到农业的可持续发展,分析安徽省的蒸散量变化,对水资源的科学配置和合理利用有着重要的意义。基于MOD16蒸散量产品,利用均值、标准差、偏差法、趋势分析法以及空间变异等方法,分析安徽省近15 a地表蒸散量年际、年内时空变化特征,和不同土地利用类型下蒸散量的差异性变化特征。研究表明:(1)2000~2014年间安徽省多年平均蒸散量为694.9 mm,波动范围为647.5~730.5 mm,年际变化呈现下降趋势;并具有较强的空间分异性规律,整体上呈现南高北低趋势,各市多年蒸散量均值差异显著,其中黄山的蒸散量最高(844.1 mm),宿州最低(603.7 mm)。(2)安徽省年内各月间的蒸散量呈现先增加后减少的“单峰型”趋势,具有明显的季节差异,表现为夏季(304.17 mm)>春季(167.56 mm)>秋季(150.41 mm)>冬季(73.92 mm);但各市的年内蒸散量变化趋势表现不同,淮河以南整体呈现“单峰型”趋势,淮河以北则呈现典型的“双峰型”趋势。(3)安徽省不同土地利用类型的蒸散量差异明显,其年均蒸散量按照“林地>草地>未利用地>耕地>城镇用地”的顺序递减。 关键词: MOD16; 安徽省; 蒸散量; 时空分布; 土地利用  相似文献   
293.
新型高效分散阻垢剂XH-929的性能及应用   总被引:4,自引:1,他引:3  
分散阻垢剂XH-929对循环冷却水中CaCO3、Fe2O3、MgSiO3、Ca3(PO4)2的沉积结垢有很好的抑制作用,且能在碱性条件下稳定Zn2+。动态模拟试验和工业应用实例表明,XH-929分散阻垢剂与适量缓蚀剂复配后,可起到较好的阻垢、缓蚀作用。  相似文献   
294.
We measured the in situ suspended sediment concentration (SSC) and hydrodynamics (waves, currents, and sea level) concurrently during a storm event using self-recording instruments at offshore of the Shandong Peninsula in the Yellow Sea. We analyzed the temporal variation in suspended sediment carrying capacity and its correlation with wave, current, and water-level conditions. There was about 40% increase in SSC during the storm event. A 3-4-h lag was observed between the peak of wave height and SSC. The SSC increased in a fluctuating pattern up to the peak then decreased rapidly. This process was positively correlated with wave height and duration. The maximum SSC was 524.3 mg/l, which is about 10 times of that under normal weather conditions. This peak was observed after of a series of 1.8 m waves. The increased suspended sediments were the fine particles resuspended by the storm waves from seabed near the observation spot and transported by northward ebb currents from Shidao Bay.  相似文献   
295.
In the Wei River basin, the ecosystem is gradually deteriorating due to the rapid growth of the population and the development of economies. It is thus important to assess the ecosystem health and take measures to restore the damaged ecosystem. In this study, an index of biotic integrity (IBI) for fish was developed to aid the conservation of the ecosystem based on a calibration data set. An index of water and habitat quality (IWHQ) was calculated based on environmental variables and habitat quality (QHEI) to identify the environmental degradation in the studied sites. The least degraded sites (IWHQ?≤?2; W1, W5, W10, W12, W13, W14, and W16) were chosen as the reference sites. Six metrics that are sensitive to environmental degradation were utilized to differentiate the reference and the impaired sites using statistical methods. These metrics included the number of species (P1), the total biomass (P2), the number of Cobitidae species (P8), the proportion of species in the middle and low tiers (P10), the proportion of individuals that were classified as sensitive species (P25), and number of individuals in the sample (P39). A continuous scoring method was used to score the six metrics, and four classes were defined to characterize the ecosystem health of the Wei River basin. The fact that the overall IBI scores were negatively correlated with the index of environmental quality (IWHQ) based on the validation data set indicated that the index should be useful for biomonitoring and the conservation of biodiversity. According to the results, more than half of the sites were classified as poor or very poor. The ecosystem health in the Wei River was better than that in the Jing River and the Beiluo River, and this study will be a great reference for water resources management and ecosystem restoration in the Wei River basin.  相似文献   
296.
采出水经处理后通常需作为地层回注水使用,由于油气生产的特殊性,常用的H2S脱除方法在使用中受到限制,探索适合于油气田生产的水处理方法十分必要。文章探讨了通常可用于油田采出水中H2S脱除的各种方法,对比了各类方法的优缺点,提出以NaClO为主要脱硫剂的水处理方法,通过对模拟采出水的室内实验,证明次氯酸法可以快速有效地去除采出水中的H2S,使H2S残留量低于1 mg/L。实验表明:经处理后的水质可以达到SY/T 5329-2012《碎屑岩油藏注水水质指标及分析方法》要求,处理成本较低。  相似文献   
297.
利用FISH和DGGE对产甲烷颗粒污泥中微生物种群的研究   总被引:12,自引:6,他引:6  
邢薇  左剑恶  孙寓姣  李建平 《环境科学》2006,27(11):2268-2272
利用FISH和DGGE技术对厌氧反应器内处于不同运行阶段的4个产甲烷颗粒污泥进行研究,考察其中真细菌和古细菌的种群结构,并对其中的优势古细菌进行系统发育分析.FISH结果表明,颗粒污泥中真细菌含量明显高于古细菌,真细菌主要分布在颗粒污泥外层,古细菌则主要分布在内层;DGGE结果表明,随着反应器COD负荷的增加以及运行时间的延长,真细菌种群结构相对较稳定,而古细菌种群结构则发生了较明显变化,其中占优势的古细菌种类逐渐减少;将有代表性的7个古细菌条带切胶回收并测序,结果显示,反应器运行后期占优势的菌种主要包括甲烷微粒菌(Methanocorpusculum)、甲烷杆菌(Methanobacterium)和甲烷髦毛菌(Methanosaeta)等.  相似文献   
298.
Environmental Science and Pollution Research - Grid-based sand-fixing protection barriers have been widely used to solve linear engineering problems in sandy areas. Their placement directly affects...  相似文献   
299.
粉煤灰资源化利用发展战略的研究   总被引:3,自引:0,他引:3  
运用系统工程原理和运筹学的分析方法,对南京地区粉煤灰资源化利用的发展战略、制约因素及政策措施进行了分析,提出了一些方案措施,为南京市规划、管理和制定用灰政策提供了必要的科学依据。  相似文献   
300.
IntroductionWastewatersfrombatterymanufacturing ,printing ,painting ,dyeingandotherindustrialprocessesoftencontainconsiderableamountsofheavymetalsthatwouldendangerpublichealthifdischargedwithoutadequatetreatment.Long termingestionofwatercontaininghigherco…  相似文献   
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