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1.
Fractionations of rare earth elements (REEs) and the forming mechanisms in plants were studied using Triticum aestivum as plant material with application of exogenous REEs and hydroponic culture. REEs were significantly fractionated in different parts of Triticum aestivum. M-type tetrad effect could be observed in both root and shoot of Triticum aestivum, which might result from the different abilities of REEs to form phosphate precipitation. Middle REEs (MREEs), light REEs (LREEs) and heavy REEs (HREEs) were enriched in root, stem and leaf of Triticum aestivum, respectively. REE speciation calculations using VMINTEQ program show REEs in simulated xylem solution mainly exist as REE-EDTA- and RE3 , but only HREEs are enriched in REE-EDTA-, while LREEs are enriched in the other REE species. It is suggested that the fractionation between LREEs and HREEs might be caused by the uptake of REE-EDTA- in Triticum aestivum leaves, but might result from the uptake of the other REE species in their stems.  相似文献   

2.
对我国二十种土壤中稀土元素形态分组的研究   总被引:2,自引:0,他引:2  
翟海  杨永岗  胡霭堂 《稀土》2001,22(3):1-5
本文提出了土壤中稀土元素形态分组的方法,对我国20种土壤中稀土元素形态分组特征进行了评价。结果表明,土壤中稀土元素主要以残渣态存在,其次为氧化铁结合态和松结有机态。在碱性土壤中碳酸盐结合态仅次于氧化铁结合态,中酸性土壤中紧结有机态仅次于松结有机态,而碱性土壤中紧结有机态极低。土壤中交换态和氧化锰结合态稀土元素均比较低。  相似文献   

3.
Accumulation of Rare Earth Elements in Various Microorganisms   总被引:1,自引:0,他引:1  
The removal of rare earth elements (REEs) from solution in various microorganisms was examined. Seventy-six strains from 69 species (22 bacteria, 20 actinomycetes, 18 fungi, and 16 yeasts) were tested. Initially, Sm was used to test the removal capabilities of the various organisms. Gram-positive bacteria, such as Bacillus licheniformis, B. subtilis, Brevibacterium helovolum, and Rhodococcus elythropolis, exhibited a particularly high capacity for accumulating Sm. In particular, the B. lichemiformis cells accumulated approximately 316 μmol Sm per gram dry wt. of microbial cells. A full suite of screenings was then conducted to compare the abilities of the organisms to remove Se, Y, La, Er, and, Lu from solution. Tests were done with solutions containing one REE at a time. Accumulation was nearly identical for the various metals and organisms. However, when solutions with equimolar amounts of two REEs were used, preferential removal from solution was observed. When an Eu/Gd solution was used, gram-positive bacteria removed more Eu and Gd as compared to actinomycetes. When Eu/Sm combination was used, gram-positive bacteria removed equal mounts of both metals and some actinomycetes removed more Eu. The selective removal was quantified by calculating separation factors (S. F.), which indicated that Streptomyces levoris cells accumulated the greatest proportion of Eu. The removal of REEs from a solution containing five metals (Y, La, Sm, Er, and Lu) was then examined. Mucorjavanicus preferentially accumulated Sm and S. flavoviridis preferentially accumulated Lu. The effects of pH and Sm concentration on the accumulation of Sm by B. licheniformis were also examined. Accumulation increased at higher pH and at greater solution concentrations.  相似文献   

4.
Therearemanyreportsofstudiesontheeffectsonplantsbyacidrain[1~ 3 ] andutiliza tionofREE[4~ 7] andafewstudiesonREEus ingaschemicaladjustmenttoprotectingplantsfrombeingdamagedbyacidrainstressundernaturalcondition .ThisstudywasfocusedontheaccumulationofREEinspin…  相似文献   

5.
Withsimilarchemicalproperties ,rareearthelementsarealwaysparageneticinnatu ralenvironment.However ,REEmaybefrac tionatedinvariousgeochemicalconditionsow ingtotheminutediscrepancyamongatomicstructuresandchemicalpropertiesofREE .Furthermore ,distributionstat…  相似文献   

6.
稀土元素的特殊性质及其应用   总被引:5,自引:0,他引:5  
本文从稀土元素微观结构角度,揭示了稀土元素的某些特殊性质,并指出这种特性与应用机理有必然的联系。从而启迪稀土使用者,掌握和了解稀土的基本特性,才能自由地驾驭稀土的应用。  相似文献   

7.
Teapolysacchridecomplex ,oneofthebasicmacromoleculesintea ,hasmanyphar maceuticaleffectsandiseasytodissolveinteainfusion[1] .Zhongetal .[2 ] discoveredthatthereisaREbindingpolysaccharideinleavesofteaplant (CamelliaSinensisLO .Kuntze) .Inthispaper ,thestudyontheco…  相似文献   

8.
Yunkai uplifted area is one of the important metallogenic areas in Guangdong and Guangxi Provinces, in which many gold, silver, tungsten, tin, lead, zinc, molybdenum, and iron deposits were found. Dongtian gold deposit in the middle of Yunkai uplifted area, western Guangdong Province, is chosen as an example of those deposits. Comparative studies on the chondrite - normalized REE patterns and ∑REE, LREE/HREE, δEu, δCe, NLa/Yb, and NLa/Sm of auriferous quartz veins, altered gneiss-type goM ores, Caledonian gneissic biotite granite, and Late Yanshanian granite porphyry were made. The results indicate that the source of the metallogenic materials of the auriferous quartz veins and the altered gneiss-type gold ores are the same, and both of them come from the gneissic biotite granite. Metallogenic epoch of the deposit is estimated to be Caledonian period.  相似文献   

9.
许胜先  王志强 《稀土》2003,24(4):68-70
合成了十二种稀土锗钨钼酸根多元杂多配合物。利用元素化学分析和ICP相结合方法、IR等手段对配合物进行了初步表征。  相似文献   

10.
章健  承河元  张自立 《稀土》2002,23(6):43-45
在试验生态小区的土壤中,模拟长期使用稀土产生的积累以探讨稀土积累与水稻白叶枯病发生发展的关系。研究结果表明:0.5%,1%,3%,5%,7%,10%吸附容量和40g/亩的稀土以及土壤中2000g/亩和40g/亩的稀土复合肥添加剂对水稻白叶枯病发生后的病情指数影响无显著差异。  相似文献   

11.
Rareearthelements (REEs)werewidelyappliedtotracingthesourcesofmaterialsandtostudyingtheirevolutionprocessesinmanyfieldsofearthscienceinconsiderationoftheirsimilarityandsystematicdiffer enceinchemicalproperties .Furthermore ,lanthanidesarebothimportantprod…  相似文献   

12.
TheYueshanregionisnearbyAnqing ,Anhuiprovince .ItisgeotectonicallylocatedatthenorthernmarginoftheYangtzeParaplat form ,consistentwiththemiddlepartoftheChangjiangdeepfracturezoneofthelowerYangtzePlatformdepression(Fig .1 ) .Thede positsofskarntypearetheforemo…  相似文献   

13.
Rareearth (RE)micro fertilizershavebeenusedinagricultureproductioninChinasince 1 970s ,andthesemicro fertilizersaresaltsofmixedREs ,whichmainlyincludeLa ,Ce ,PrandNd[1,2 ] .PreviousstudiesshowthattheREinsurfacesoilalmostdoesnotmigratdownwardatallandthusbeaccumula…  相似文献   

14.
土壤中可给态稀土元素的研究进展   总被引:14,自引:0,他引:14  
本文综述了土壤中可给态稀土元素与植物生长的相关性,土壤中可给态稀土浸提剂的选择以及定量测定方法的研究,详细讨论了我国主要土壤中可给态稀土元素的含量、分布及其影响因子,并提出在今后研究中应值得关注的几个方面,为合理施用稀土微肥提供科学依据。  相似文献   

15.
稀土化学热处理与稀土材料表面改性   总被引:12,自引:2,他引:10  
黄拿灿  胡社军 《稀土》2003,24(3):59-63
综述了稀土元素在化学热处理与某些其它表面工程领域中的应用情况,结合笔者的研究工作,介绍了稀土元素在渗碳、渗硼、离子注入、电弧离子镀等方面对工艺过程和改性效果的影响。稀土元素对钢的渗碳和渗硼过程有明显的催化作用,渗速提高20%~30%;对提高渗碳层和渗硼层的品质和磨损特性、强韧性也有良好的效果。在离子注入技术中,稀土元素能使经离子束改性的材料表面硬度和耐磨性大为提高。在电弧离子镀中,对提高膜-基结合力有明显的效果。本文对稀土元素的合金化作用作了分析讨论和概括。  相似文献   

16.
Boridingcansignificantlyimprovesurfacepropertiesofsteels,andthusisaprosperoussurfacestrengtheningprocesswhichhasal readybeenusedintreatingsomediesandcut tingtools[1 ] .However,thereexistsomeprob lemsinboriding .Firstly ,boridingisgenerallyperformedattempera…  相似文献   

17.
Mg-Li alloy , which is also called superlight al-loy ,has many advantages ,such as lowdensity ,highstiffness-to-weight ratio , superior strength-to-weightratio ,good deformation ability ,good damping ability ,and high energetic particle penetration resistance[1 ,2].These advantages provide promising applicationsintheaerospace , electronic industry , and military field[3].Mg-Li alloys ,such as LA141 , LA191 ,and LAZ933were developed and have been usedfor components insatellites and aircrafts…  相似文献   

18.
The geochemical features of rare earth elements (REEs) in the North and South sewage discharge channels of Tianjin were studied. The results show that concentrations of dissolved REEs in water of the sewage discharge channels are very low, while concentrations of Eu and heavy REEs are higher than those in natural rivers. Concentrations of REEs in unfiltered water are high and they mainly resided on suspended matter. Distribution patterns of the dissolved and suspended light REEs vary reversely with the atomic number. Concentrations of REEs in the sediments and suspended matter are lower than those in natural rivers, and concentrations of REEs in the suspended matter are much lower than those in the sediments. Distrib.ution patterns of REEs in sediments and suspended matter were similar with light REE enrichment and positive Eu-anomaly. This distribution pattern is different from those of natural rivers. The differences may cause by the large amount of organic pollutants in sewage.  相似文献   

19.
Effect of Rare Earth Elements on Kinetics of Salt Bath Vanadizing  相似文献   

20.
Vertisol developed on argillaceous rocks has its special pedogenic processes and properties, and formed some secondary no,Jules. In study area, contents of rare earth elements (REE) are significantly different in different sedimentary rocks due to varied contents of clay fraction and clay mineral composition, etc. Under the dry and hot climate, REEs were less differentiated than their parent sedimentary rocks. However, REEs in secondary nodules formed in pedogenic process display their specific behaviors. They are more concentrated in iron concretions, the content of heavy REEs increases relatively, and positive Ce-anomaly appeares. But, negative Ceanomaly was found in calcium concretions, while normal Cecontent in parent recks and vertisol.  相似文献   

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