排序方式: 共有21条查询结果,搜索用时 31 毫秒
1.
利用连续流2450MHz的电磁波污泥脱水装置,对2种不同的污泥进行均匀性试验,得到加载功率270W、加载时间200s、加载泥量150mL工况最优.该工况下,污泥离心含水率、沉降含水率、SV分别由原泥的90.46%、96.35%、88%下降到87.32%、95.55%、76%,比阻由2.37?109m/kg升高至1.22?1010m/kg ,在同等离心条件下,经过2450MHz电磁波处理的污泥体积比不经电磁波处理的体积减少了25%.加载后,TN、TP、SCOD的最大溶出倍数分别达到了17.69、9.50和40.11,EPS降低61.9%,与现有的微波加载实验结果对比发现,在原泥比阻值较低情况下,连续流状态下比阻值未降反增,但污泥胞内物质的溶出倍数明显更大,能有效降低EPS,改善污泥脱水性能,表明了2450MHz电磁波动态污泥脱水的效果更好. 相似文献
2.
在深入分析地震新闻报道同质化特征及其原因的基础上,本文认为有效解决地震新闻报道同质化的途径有三:一是相关部门要转变思想,明确地震新闻在地震科普中的重要作用;二是新闻媒体要转变地震新闻报道方式,追求差异化报道;三是要引导受众转变新闻消费观念,以刺激新闻生产者的积极性。 相似文献
3.
E. A. Kleshcheva 《Russian Journal of Ecology》2007,38(2):94-100
A method for estimating the current state of plant communities based on the ecological amplitudes of constituent species is proposed. An original program, Fitoindikatsiya, has been developed to compute the indices of disturbance and homogeneity of plant communities from species ecological scale values. The current state of pine forests in the part of Novosibirsk oblast east of the Ob River has been analyzed; slightly, moderately, and severely disturbed zones have been distinguished. 相似文献
4.
5.
为提高复杂基体重金属检测准确性,在使用电感耦合等离子体发射光谱法检测生活垃圾焚烧飞灰浸提液时,进行标准曲线法、标准加入法和内标法3种定量校准方法比对。3种方法报出结果经过加标回收率换算后的样品原值具有明显一致性,使用统计学方差齐性和单因素方差分析验证了该一致性成立,表明内标法的精密度和准确度与标准曲线法、标准加入法无显著性差别。以3种方法样品原值的算数平均值作为样品最佳估计值评价各方法实际报出结果准确性,标准加入法准确性最好;稀释后的样品内标法加标回收率明显优于标准规定,受稀释倍数影响不大,工作效率高,满足HJ 781—2016质控要求,建议可作为该标准的补充;建议批量样品检测时优先采用内标法。3种方法样品原值一致性的验证,有助于执法、科研中对于复杂基体重金属物质含量的准确判断。 相似文献
6.
Ma. Librada Chu Abduwasiti Ghulam Jason H. Knouft Zaitao Pan 《Journal of the American Water Resources Association》2014,50(4):928-942
A thorough understanding of past and present hydrologic responses to changes in precipitation patterns is crucial for predicting future conditions. The main objectives of this study were to determine temporal changes in rainfall‐runoff relationship and to identify significant trends and abrupt shifts in rainfall and runoff time series. Ninety‐year rainfall and runoff time series datasets from the Gasconade and Meramec watersheds in east‐central Missouri were used to develop data screening procedure to assess changes in the rainfall and runoff temporal patterns. A statistically significant change in mean and variance was detected in 1980 in the rainfall and runoff time series within both watersheds. In addition, both the rainfall and runoff time series indicated the presence of nonstationary attributes such as statistically significant monotonic trends and/or change in mean and variance, which should be taken into consideration when using the time series to predict future scenarios. The annual peak runoff and the annual low flow in the Meramec watershed showed significant temporal changes compared to that in the Gasconade watershed. Water loss in both watersheds was found to be significantly increasing which is potentially due to the increase in groundwater pumping for water supply purposes. 相似文献
7.
8.
韩颖 《中国个体防护装备》2012,(3):23-26
有证实物标准样品"石材放射性标准样品"、"陶瓷产品的放射性标准样品"及"粉煤灰砌块的放射性标准样品"适用于γ谱仪校准和考核相近基质样品中所含放射性核素226Ra、232Th和40K含量测定的准确性,覆盖了建材产品需要检验的所有核素,达到放射平衡。样品由8家权威放射性检测机构采用低本底多道γ能谱仪测量方法进行定值测量,均匀性和稳定性良好,以对人们的安全与健康提供保护。 相似文献
9.
We studied the mass-related aerosol properties, simultaneously attwo sites at the urban roof top level in the same city. Nosystematic influence of the wind vector on the difference in theaerosol concentrations between the two locations could be found.These results are compared with results from a second, similarexperiment over a larger distance including one urban and onerural site. Surprisingly, we could not detect a tendency whichwould indicate that sampling air at distance in the order of 1 kmwould be less affected by the heterogeneity than samplingdistanced in the order of 10 km apart. On the contrary, theresults suggest that mass-related properties at two sites in thesame city are not necessarily more similar than at an urban and arural site outside the city. These results stress the limitedhorizontal homogeneity of urban atmospheric aerosol. As aconclusion it is suggested that single-site measurements of mass-related aerosol properties should be considered to berepresentative for an area smaller than 1 km2 on size. 相似文献
10.
FENGQING LI YONG‐SU KWON MI‐JUNG BAE NAMIL CHUNG TAE‐SUNG KWON YOUNG‐SEUK PARK 《Conservation biology》2014,28(2):498-508
Globally, the East Asian monsoon region is one of the richest environments in terms of biodiversity. The region is undergoing rapid human development, yet its river ecosystems have not been well studied. Global warming represents a major challenge to the survival of species in this region and makes it necessary to assess and reduce the potential consequences of warming on species of conservation concern. We projected the effects of global warming on stream insect (Ephemeroptera, Odonata, Plecoptera, and Trichoptera [EOPT]) diversity and predicted the changes of geographical ranges for 121 species throughout South Korea. Plecoptera was the most sensitive (decrease of 71.4% in number of species from the 2000s through the 2080s) order, whereas Odonata benefited (increase of 66.7% in number of species from the 2000s through the 2080s) from the effects of global warming. The impact of global warming on stream insects was predicted to be minimal prior to the 2060s; however, by the 2080s, species extirpation of up to 20% in the highland areas and 2% in the lowland areas were predicted. The projected responses of stream insects under global warming indicated that species occupying specific habitats could undergo major reductions in habitat. Nevertheless, habitat of 33% of EOPT (including two‐thirds of Odonata and one‐third of Ephemeroptera, Plecoptera, and Trichoptera) was predicted to increase due to global warming. The community compositions predicted by generalized additive models varied over this century, and a large difference in community structure in the highland areas was predicted between the 2000s and the 2080s. However, stream insect communities, especially Odonata, Plecoptera, and Trichoptera, were predicted to become more homogenous under global warming. Impacto Potencial del Calentamiento Global sobre la Diversidad y la Distribución de Insectos de Arroyo en Corea del Sur 相似文献