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301.
分析松花江流域沉积物中三磷酸腺苷(ATP)微生物量的分布,结果表明,ATP分布具有显著的空间特征,在河流发源地及部分城市地区河流段沉积物中具有高的ATP含量,统计分析(主成分分析,多元回归树分析和响应模型分析)表明:ATP是沉积物的主要成分性质之一,在本研究所涉及11个因子中,影响ATP分布变异的第一因子是空间位置(纬度,39.79%),然后是环境因子(总氮,18.49%;硝氮,16.24%),其中ATP随纬度呈二次曲线变化(P<0.001),与总氮呈显著正相关(P=0.027),和硝氮呈显著负相关(P<0.01).同时ATP也随有机质、总磷和海拔的增加而呈增加趋势(P<0.05).沉积物ATP与多种营养元素及其不同形态具有显著相关性,表明通过ATP活性微生物量可以反映水体环境的营养水平. 相似文献
302.
新型饮用水除氟材料Bio-F除氟机制研究 总被引:1,自引:0,他引:1
采用了SEM、BET、FT-IR、XRD等现代分析测试方法,研究了Bio-F的表面微观结构及吸附氟离子机制.结果表明,Bio-F吸附氟离子后比表面积由12.411m2·g-1减少为10.692m2·g-1,平均孔容减少了0.004 cm3·g-1,最可几孔径分布在1.88nm左右.Bio-F吸附氟离子的过程包括离子交换和吸附作用,吸附方式包括物理吸附和化学吸附,离子交换时材料与氟离子结合可能形成Ca10(PO4)5CO3(OH)F. 相似文献
303.
以贵州省铜仁市汞矿区汞污染土壤为研究对象,分别采用KI、Na_2S_2O_3、乙二胺四乙酸、柠檬酸、酒石酸、十二烷基硫酸钠溶液对其进行淋洗修复,筛选出合适的淋洗剂,优化了淋洗条件,并探索了淋洗液的处理方法。实验结果表明:对该土壤淋洗效果最好的淋洗剂为Na_2S_2O_3,最佳淋洗条件为Na_2S_2O_3浓度0.01 mol/L、固液比(g/m L)1∶5、淋洗时间4 h、淋洗次数1次,在此条件下土壤中总汞的淋洗率为13.41%,有效态汞含量可降至原来的61.54%;Na2S对淋洗液中的汞具有较好的去除效果,每升淋洗液加入0.6 g Na_2S处理后,即可满足GB8978—1996《污水综合排放标准》。 相似文献
304.
305.
为有效预防由于个人防护缺失所造成的事故,着力探究复杂作业情况下施工人员安全帽佩戴情况的智能化识别.提出在Faster R-CNN目标检测算法的基础上,针对小目标的安全帽识别问题通过增加锚点提升检测能力,为解决数据集中类别不平衡问题采用Focal loss替代原本的损失函数,为解决安全帽预测区域不匹配问题,引入ROI A... 相似文献
306.
Guofeng Wu Lijuan Cui Hongtao Duan Teng Fei Yaolin Liu 《Environmental monitoring and assessment》2013,185(5):4191-4206
Obtaining and analyzing the specific inherent optical properties (SIOPs) of water bodies is necessary for bio-optical model development and remote sensing-based water quality retrievals and, further, for related ecological studies of aquatic ecosystems. This study aimed to measure and analyze the specific absorption and backscattering coefficients of the main water constituents in Poyang Lake, China. The specific absorption and/or backscattering coefficients of the main water constituents at 85 sampling sites (47 in 2010 and 38 in 2011) were measured and analyzed as follows: (1) the concentrations of chlorophyll a (C CHL), suspended particulate matter (C SPM) (including suspended particulate inorganic matter (C SPIM) and suspended particulate organic matter (C SPOM)), and the absorption coefficients of total particulate (a p), phytoplankton (a ph), and non-pigment particulate (a d) were measured in the laboratory; (2) the total backscattering coefficients at six wavelengths of 420, 442, 470, 510, 590, and 700 nm, including the contribution of pure water, were measured in the field with a HydroScat-6 backscattering sensor, and the backscattering coefficients without the contribution of pure water (b b) were then derived by subtracting the backscattering coefficients of pure water from the total backscattering coefficients; (3) the specific absorption coefficients of total particulate ( $ a_{\mathrm{p}}^{ * } $ ), phytoplankton ( $ {a_{{\mathrm{ph}}}}^{ * } $ ), and non-pigment particulate ( $ a_{\mathrm{d}}^{ * } $ ) were calculated by dividing a p, a ph, and a d by C SPM, C CHL, and C SPIM, respectively, while the specific backscattering coefficients of total suspended particulate matter ( $ b_{\mathrm{b}}^{ * } $ ) were calculated by dividing b b by C SPM; and (4) the $ {a_{{\mathrm{ph}}}}^{ * } $ , $ a_{\mathrm{d}}^{ * } $ , $ a_{\mathrm{p}}^{ * } $ and $ b_{\mathrm{b}}^{ * } $ of the remaining samples (46 in 2010 and 36 in 2011) were visualized and analyzed, and their relations to C CHL, C SPIM or C SPM were studied, respectively. The main results are summarized as follows: (1) the $ {a_{{\mathrm{ph}}}}^{ * } $ values at 440 nm were 0.0367–0.7203 m2?mg?1 with a mean of 0.1623?±?0.1426 m2?mg?1 in 2010 and 0.0319–0.7735 m2?mg?1 with a mean of 0.3145?±?0.1961 m2?mg?1 in 2011; there existed significant, negative, and moderate correlations between $ {a_{{\mathrm{ph}}}}^{ * } $ and C CHL at 400–700 nm in 2010 and 2011 (p?<?0.05); (2) The $ a_{\mathrm{d}}^{ * } $ values at 440 nm were 0.0672–0.2043 m2?g?1 with a mean of 0.1022?±?0.0326 m2?g?1 in 2010 and 0.0559–0.1347 m2?g?1 with a mean of 0.0953?±?0.0196 m2?g?1 in 2011; there existed negative correlations between $ a_{\mathrm{d}}^{ * } $ and C SPIM, while the correlations showed overall decreasing and increasing trends before and after around 575 nm with increasing wavelengths, respectively; (3) The $ a_{\mathrm{p}}^{ * } $ values at 440 nm were 0.0690–0.1929 m2?g?1 with a mean of 0.1036?±?0.0298 m2?g?1 in 2010 and 0.0571–0.1321 m2?g?1 with a mean of 0.1014?±?0.0191 m2?g?1 in 2011, and the negative correlations between $ a_{\mathrm{p}}^{ * } $ and C SPM were found in both years; (4) The $ b_{\mathrm{b}}^{ * } $ at the six wavelengths generally decreased with increasing wavelengths, while the $ b_{\mathrm{b}}^{ * } $ values at 420 nm were lower than those at 442 nm for some samples; the correlation between $ b_{\mathrm{b}}^{ * } $ and C SPM increased with increasing wavelength. Such results can only represent the SIOPs during the sampling time periods, and more measurements and analyses considering different seasons need to be carried out in the future to comprehensively understand the SIOPs of Poyang Lake. 相似文献
307.
采用地面站点观测、卫星观测以及UWCM 0-D箱子模型模拟的方法研究湖北2013—2015年臭氧时空分布特征,并探讨其管控措施。从地面站点观测看出,时间分布上,这3年臭氧年平均浓度经历先下降后上升的过程,总体呈上升趋势,而二氧化氮年平均浓度则呈现持续下降的趋势;空间分布上,湖北各区域臭氧浓度分布不均匀,呈现东高西低的递减分布趋势。从卫星观测数据看出,2015年湖北的臭氧柱浓度高于2013、2014年同期。从空间分布来看,臭氧的柱浓度是从东北到西南、从省外到省内逐渐递减,因此推测,除了本地生成,湖北的臭氧有一部分是来源于省外传输。最大臭氧生成量法显示,烯烃(乙烯和丙烯)对湖北夏天臭氧生成量的贡献远大于其他挥发性有机化合物。箱子模型模拟的结果显示,湖北应该通过控制挥发性有机化合物的排放来降低臭氧生成速率,控制氮氧化物反而使臭氧生成速率提高。 相似文献
308.
309.
A case study was conducted on the forest ecosystem in the Baishuijiang River basin of China to reveal the influences of environmental
factors and human disturbance on the floristic characteristics and biodiversity patterns. Field surveys of the floristic composition,
environmental factors, and disturbance factors were conducted along an elevation gradient, and the relationships between biodiversity
pattern and environmental factors were analyzed using CCA (canonical correspondence analysis). The results showed that the
floristic composition of higher plants consisted of 197 families, 796 genera, 2165 species, 19 subspecies, 239 varietas, and
12 forma, and it was characterized by the multi-geographic composition and by the transition from tropical to temperate zones.
Along an elevation gradient, the variations in α and β diversity were best described by a bimodal curve, and the peak values
occurred at middle elevations. The CCA indicated that the elevation had the greatest influence on the biodiversity pattern,
followed by the topographic index, slope direction, slope, slope position, slope shape, and vegetation coverage. In addition,
human disturbance has greatly impacted the floristic composition and biodiversity patterns, and the biodiversity indices were
higher with intermediate disturbance at middle elevations compared to higher and lower disturbances at low and high elevations,
respectively. This reflected a disturbance–diversity pattern and thus revealed the obvious importance to maintain the intermediate
disturbance for biodiversity conservation. 相似文献
310.
贵州高原三板溪水库浮游植物功能群时空分布特征 总被引:9,自引:0,他引:9
为探究贵州高原三板溪水库的浮游植物功能群时空分布特征,于2012—2013年枯水期(11月)、平水期(4月)、丰水期(7月)对三板溪水库浮游植物与水样进行分层采样分析.研究结果表明,水库浮游植物可分为21个功能群,其优势功能群具有明显的水期分布特征:枯水期P+X1+D+J→平水期P+B+C+G→丰水期M+H1+S1+J,垂直分布中平水期和丰水期优势功能群在10 m左右发生变化,枯水期在70 m处变化;各时期水体热分层及营养物质分布差异是产生该特征的主要原因;浮游植物功能群时空分布特征受环境变化影响,水温、p H和N/P变化是浮游植物功能群结构变化的最主要因素;浮游植物功能群生长策略变化规律为:枯水期CR/C/S策略藻种→平水期R/CR/CS策略藻种→丰水期S/CS/CR/R策略藻种;通过浮游植物功能群与生境之间的相互关系可以得出:三板溪水库水体处于富营养状态. 相似文献