期刊文献+
共找到2篇文章
< 1 >
每页显示 20 50 100
Application of Geochemistry and VNIR Spectroscopy in Mapping Heavy Metal Pollution of Stream Sediments in the Takab Mining Area, NW of Iran
1
作者 Parisa PIROOZFAR Samad ALIPOUR +1 位作者 Soroush MODABBERI David COHEN 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2018年第6期2382-2394,共13页
This study considered the possibility of using visible and near infrared(VNIR) spectral absorption feature parameters(SAFPs) in predicting the concentration and mapping the distribution of heavy metals in sediments of... This study considered the possibility of using visible and near infrared(VNIR) spectral absorption feature parameters(SAFPs) in predicting the concentration and mapping the distribution of heavy metals in sediments of the Takab area. In total, 60 sediment samples were collected along main streams draining from the mining districts and tailing sites, in order to measure the concentration of As, Co, V, Cu, Cr, Ni, Hg, Ti, Pb and Zn and the reflectance spectra(350–2500 nm). The quantitative relationship between SAFPs(Depth500 nm, R610/500 nm, R1344/778 nm, Area500 nm, Depth2200 nm, Area2200 nm, Asym2200 nm) and geochemical data were assessed using stepwise multiple linear regression(SMLR) and enter multiple linear regression(EMLR) methods. The results showed a strong negative correlation between Ni and Cr with Area2200 nm, a significant positive correlation between As and Asym2200 nm, Ni and Co with Depth2200 nm, as well as Co, V and total values with Depth500 nm. The EMLR method eventuated in a significant prediction result for Ni, Cr, Co and As concentrations based on spectral parameters, whereas the prediction for Zn, V and total value was relatively weak. The spatial distribution pattern of geochemical data showed that mining activities, along with the natural weathering of base metal occurrences and rock units, has caused high concentrations of heavy metals in sediments of the Sarough River tributaries. 展开更多
关键词 heavy metals SAFPs VNIR spectroscopy multiple linear regression takab Iran
下载PDF
再析建部贤弘“缀术”之本质——兼论《缀术算经》的数学体系
2
作者 夏青 徐泽林 《上海交通大学学报(哲学社会科学版)》 CSSCI 北大核心 2013年第2期84-91,共8页
《缀术算经》(1722)是江户时代的一本重要的和算书,中日学者从不同角度分析了其中的内容,然而对于该书十二道算题中的"解题本术"所蕴涵的数学思想只有一些零星讨论,并没有展开系统研究,至于其"缀术"的本质,一般均... 《缀术算经》(1722)是江户时代的一本重要的和算书,中日学者从不同角度分析了其中的内容,然而对于该书十二道算题中的"解题本术"所蕴涵的数学思想只有一些零星讨论,并没有展开系统研究,至于其"缀术"的本质,一般均认为是今日所谓的归纳法。事实上,其"缀术"的思想集中反映在其十二道算题的"解题本术"之中。本文通过对"解题本术"进行系统分析,认为其"缀术"的本质乃将"算法单元"连缀起来的方法。其中的"法则、术理、员数"是对数学内容的分类,"理"、"术"、"数"是解法系统的组成部分,而"据理探"和"据数探"则是缀术的基本方法,数学内容、解法系统、探索方法共同构成了《缀术算经》的数学体系。 展开更多
关键词 建部贤弘 缀术 算法单元
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部