简介：~~

简介：Thedistributionofrareearthelement(REE)formsinsoilsisgiveninthepresentpaperonthebasisofsequentialfractionationanddeterminationof34representativesurfacesoilscollectedfromallpartsofChina.ResultsobtainedshowthattheextractionrateofwatersolubleandexchangeableREEhadtheodd-evenphenomenonandthatoforganicallyboundREEfromLatoLutendedtoreducegraduallywiththeincreaseofatomicnumber.ThestabilityofScandtheactivityandenrichmentofTminsoilsareproposed.Furthermore,thepapermakesapreliminarydiscussiononthedifferencesintheconcentrationdistributionofvariousformsofindividualREEinsomesoils.

简介：Adsorptionanddesorptionofexogenousrareearthelements(REE)insoilswerestudied.ResultsshowedthatsoilshadstrongadsorbabilityforREEandtherateofadsorptionofREEwasover95%oftheaddedREEinthesetests.ThecharacteristicsofadsorptionisothermscorrespondedwellwiththebothFreundlichandTemkinequations,butdeviatedfromtheLangmuirequation.TheadsorptionofREEtendedtoincreasewiththerisingofsoilpH.AsequentialextractionmethodusedforstudingthedesorptionanddistributionofREEsorbedinsoilsarealsodiscussed.

简介：土壤侵蚀过程复杂，很难直接应用土壤侵蚀预报方程进行定量计算。作为一种新的机器学习算法，支持向量机在样本有限的情况下，采用结构风险最小化准则，把学习问题转化为一个二次规划问题，从而得到唯一的全局最优解。首次尝试将最小二乘支持向量机技术用于土壤侵蚀预测，并与BP神经网络的方法进行了对比，取得了较好的预测精度。