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1.
Effect of Lanthanum on Nitrification, Phosphorus Transformation and Phenol Decomposition in Red Soil
The effect of La on nitrification, P transformation and phenol decomposition in red soil was studied by incubation and pot culture experiments. La at low concentration has stimulative effect on soil nitrification and P transformation while its high concentration has inhibitory effects, and the inhibition is strengthened with increasing concentration of La. La has strongly inhibitory effect on soil phenol decomposition and the inhibition is strengthened with increasing concentration of La. When the incubation time is prolonged, the inhibitory effect of La on soil nitrification and phenol decomposition tends to decrease. 相似文献
2.
Adsorption of Er( Ⅲ ) and Its Mechanism on Diglycolamidic Acid Resin 总被引:15,自引:0,他引:15
Thesynthesischaracterizationandadsorp tionpropertyofpolymericmaterialshavebeenpublishedinrecentyears[1~ 9] .DiglycolamidicacidresinDAARisanovelpolymericmaterialwhichcontainsafunctionalgroup [-N(CH2 COOH ) 2 ].Itpossessesnotonlyprotonthatcanexchangewithcation ,b… 相似文献
3.
The effect and the action mechanism of lanthanum on GF43 plantlet in vitro were studied. The results of experiments show that root growth rate and dry weight of GF43 by LaCI3 treatments increase. The activities of antioxidant enzymes in root system such as superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) apparently enhance. Moreover O^-2 and malond ialdehyde (MDA) contents and cell membrane permeability of GF43 are decreased by LaC13. The relatively stable membrane structure of cell could also be maintained and the root ageing of GF43 plantlet in vitro delays. 相似文献
4.
The layer-by-layer complexation technique of polymer and metal ion was successfully utilized to fabricate the uhrathin muhilayer film of poly(3-thiophene acetic acid (PTAA) and Tb^3 ion by dipping the substrates alternatively in polymer and Tb^3 ion aqueous solutions. UV - vis measurement revealed that the absorbance has linearity with the bilayer number from layer to layer and the X-ray photoelectron spectrum (XPS) confirmed the existence of Tb^3 ion. The pH of both the polymer and TbCl3 solutions influence the thickness dramatically while the concentration of the solutions is not so sensitive. The luminescent spectrum of the complex film shows the characteristic emission of Tb^3 ion as well as the ligand indicating the formation of the complex. 相似文献
5.
Investigations on structure and proton diffusion coefficient of rare earth ion (Y^3+/Nd^3+) and aluminum codoped α-Ni(OH)2 总被引:1,自引:0,他引:1
Rare earth ion (Nd^3+/Y^3+) and Al^3+ codoped α-Ni(OH)2 powers were synthesized by chemical coprecipitation method. The structttre was analyzed with X-ray diffraction (XRD) and thermal gravity (TG). Cyclic voltammetry (CV) tests were performed to evaluate the proton diffusion coefficients of the samples. The results indicated that codoping of Y-Al and Nd-Al resulted in more water molecules contained within the crystal lattice and accordingly increased the interlayer spacing. In particular, the Y-Al codoped α-Ni(OH)2 showed a turbostratic structure. The calculated diffusion coefficients of the Y-Al codoped α-Ni(OH)2 and Nd-Al codoped α-Ni(OH)2 were 3.5×10^-10cm^2/s and 2.8× 10^-10 cm^2/s, respectively. 相似文献
6.
After comparing the sensitizing effect of various mixed surfactants on the chromophoric reaction of gallium (Ⅱ) with orthochlorophenylf luorone, it has been found that the mixed micelle of cetyltrimethylammonium bromide and Tween-80 is most suitable. In the presence of this mixed micelle, not only both the sensitivity and stability improve markedly, but also a wider pH range is tolerable for the colour-development. From the study on the optimum conditions for the formation of the coloured coordination compoundin the system of 《Ga (Ⅱ)——o-Chlorophenyl fluorone-catyltrimethylammo-nium bromide——Tween-80》 and its main characters, a spectrophotometricmethod, by which sensitivity and reproducibility are higher than those of ternary systems of gallium(Ⅱ) has been developed. When it is combined with the dual-wavelength method, the molar absorptivity can be improved to 2.33×105 l·mol-1·cm-1,which is higher than that of most of other systems ever shown in the literatures; moreover the linear range is extended. From the determination of microamount of gallium in the copper minerals, the result is proved to be acceptable. 相似文献
7.
8.
Research on poly(styrene-acrylic acid)-supported neodymium complex in catalytic copolymerization of styrene and 4-vinylpyridine 总被引:1,自引:0,他引:1
The catalytic activity of poly(styrene-acrylic acid) (PSAA) supported neodymium chloride (NdCl3) complex for the copolymerization of styrene and 4-Vinylpyridine was studied. The influence of various factors, such as Al/Nd molar ratio, reaction time, macromolecular carder (PSAA), and ratio of styrene to 4-vinypyridine (g/g), on the copolymerization yield of styrene and 4-Vinylpyridine was investigated. The results showed that the copolymerization of polar monomers with olefins occurred efficiently and the catalytic activity of polymer-supported catalyst was higher than that of the similar small molecular catalysts. The activity of PSAA.Nd complex increased with in- creasing Al/Nd molar ratios and decreased with increasing polymerization time. The highest activity of PSAA'Nd was observed at 120 min, and the highest yield was found at the ratio of styrene to 4-vinylpyridine of 4:2. DSC analysis presented that the resulted polymer had only one glass transition temperature, and showed very good thermal stability. 相似文献
9.
Nominal composition of Ca1-xZnxTiO3 : 0. 002Pr^3 + (x = 0. 000 - 0. 200) phosphors were prepared by conventional solid reaction route. XRD and PL measurements were used to investigate the solid-solution structure and luminescence properties of Zn-doped Ca1-xZnxTiO3:0.002Pr^3+ phosphors. The effect of solid-solution structure formed by substitution between Ca^2 + and Zn^2+ ions on the luminescent properties was analyzed. The results reveal that, with the increase of Zn substitution content below 0.010, lattice parameters and the intensity of excitation peak at both 260 and 330 nm as well as the corresponding 610 nm emission intensity are monotonously decreased quickly in a similar tendency. Also, the evolution of luminescence intensity and crystal cell parameters against Zn doping concentration are in good agreement. Above results are closely related with the structure change within Ca1- xZnxTiO3:0.002Pr^3+ solid-solution phase formed by the Zn ions substitution for the Ca sites. Present study reveals that the solid-solution structure formed by substitution between Ca^2+ and Zn^2+ ions has significant effect on the luminescence properties of single phase Ca1-xZnxTiO3:0.002Pr^3+ phosphors. 相似文献
10.
Toxicity of Lanthanum Against Rhizoctonia solani and Its Effect on Disease-Related Enzymes 总被引:2,自引:2,他引:2
Thoroughexperimentsandpracticeaboutrare earth(RE)elementshavebeenconductedsince 1970.ScientistsinChinahavesolvedaseriesofkey technologiesandappliedREelementssuccessfullyin agricultureproduction,andmadeChinabecomethe firstcountryapplyingREasacommercialprod… 相似文献
11.
Reaction between Lanthanum and Phosphorus in Steel 总被引:3,自引:2,他引:1
P always causes low temperature emhrittlement and temper embrittlement owing to itsgrain boundary segregation[']. Garcia C I etal. [2) reported a complex compound containingLa, O I S and P, in which LaZOZS acted as anucleation site and Fe-P precipitated on thesurface of the oxysulfide. Nevertheless, thermodynamic calculation by Seah M P showedthat La could not react with P in steel unlesstemperature is lower than 1100 T, sinceGibbs free energy of formation of LaP is positive above thi… 相似文献
12.
Ag-BaO thin films doped with lanthanum were prepared by vacuum deposition. Compared with the normal Ag-BaO thin film, there is almost no change with the shape and the peak site of the fluorescence spectrum; however, fluores-cence emission strength of the whole observation band(325 -600 nm)increases about 40%, and the increase of short wavelength range is more remarkable than that of long wavelength range, which we named “blue-stronger“ phenomenon. Analytic results show that, with the forming of intermetallic compounds between silver and lanthanum, the 4f-state energy levels lie just below the Fermi level within 5 eV. It is the energy exchange between the 4f energy levels and the conduction band that causes the increase effect of fluorescence emission, and it is the optical absorption cross section of 4f electron, which increases with the increase of energy of incidence photon, that gives rise to the “blue-stronger“ phenomenon. 相似文献
13.
Seedsearlydegeneratedoragedbyun suitablecultivationorunstoragetechniquesmayresultindecreasingofseedvigorandofthecropsoutput,especiallyforrice.Rareearthsacceleratethegerminationandgrowthofthecrops ,suchasrice ,wheat,barley ,veg etablesandoilplants[1~ 3] .Thest… 相似文献
14.
The chemical reaction between lanthanum oxide and molybdenum carbide was studied by thermodynamic calcu-lation, thermal analysis and in-situ X-ray Photoelectron Spectroscopy. The theoretical results show that at the environment allowing for the evaporation of lanthanum, such as in high vacuum, La2O3 in the La2O3-Mo materials can be reduced to metallic lanthanum by molybdenum carbide (Mo2C). To confirm the conclusion, many analysis methods such as XRD, SPS, and TG-DTA were taken. The experimental results show that the chemical state of lanthanum changes during heat-ing. It was proved, for the first time, that reacted metallic lanthanum appears at the surface of this kind of material at high temperature. 相似文献
15.
Effects of Lanthanum Ion and Its Complexes on Permeability of Pollen Plasmalemma and Pollen Germination 相似文献
16.
areearthshaveabeneficialeffectsonpromotingthecropgrowthandincreasingitsyield .Someresearchershavedemonstratedthattherareearthscannotentertheprotoplastandonlystayoutsidetheplasmamembrane[1] .Thereisanoxidation reduction (redox)systemontheplasmamembraneofpl… 相似文献
17.
Rareearthelements (REEs)areabletoincreaseyieldofcropsandimproveproductquality[1] .Inrecentyears ,REEswerewidelyusedasfertilizerinagricultureinChina[2 ] .Chenetal.[3] reportedtheconcentrationofREEsinvarioussoillayersincreasedsignifi cantlyincomparisonwiththatint… 相似文献
18.
Synthesis, Characterization and Antitumor Activity of Lanthanum(Ⅲ) Complex with Demethylcantharidate
A novel complex of lanthanum(Ⅲ) with demethylcantharidate group (DCA), Na[La(DCA)2(H2O)], was synthesized in aqueous solution and characterized by elemental analysis, molar conductance, IR, UV, 1H-NMR spectra and TG-DTA. The results suggest that lanthanum ion is seven-coordinated. Six oxygen atoms are from carboxyl groups and cyclic ethers of two DCA ligand, and on oxygen is from a H2O. The antitumor activities of the complex against HL-60 human leukemia, BGC-823 human gastric carcinoma, Bel-7402 human hepatic carcinoma, Hela human cervical carcinoma were investigated with MTT or SRB assays. Na[La(DCA)2(H2O)] exhibits stronger inhibition against certain kinds of cancer cells than Na2DCA in vitro. 相似文献