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111.
Syntheses and spectral characteristics of cadmium(II) compounds (CdSeO4, CdSeO3, and Cd(NCSe)2(nia)2) containing selenium in oxidation states (VI), (IV), and (-II) are described. In Cd(NCSe)2(nia)2, nicotinamide (nia) and selenocyanate anions are bonded to Cd atom as N-donor monodentate ligands. Nicotinamide is coordinated
through the ring nitrogen atom. The effects of these selenium compounds as well as Cd(NCS)2(nia)2 on the growth and Cd accumulation in roots and shoots of hydroponically cultivated chamomile plants (cultivar Lutea) were studied. In the applied concentration range (12–60 μmol dm−3) Cd(NCS)2(nia)2 affected neither the length nor the dry mass of roots and shoots. Other compounds applied at 24 μmol dm−3 and 60 μmol dm−3 significantly reduced dry mass of roots and shoots. Selenium oxidation state in the cadmium compounds affected Cd accumulation
in plant organs as well as Cd translocation within the plants, which was reflected in the values of bioaccumulation (BAF)
and translocation factors (S/R). Cd amount accumulated by shoots was lower than that in the roots. The highest BAF values
determined for Cd accumulation in shoots were obtained with CdSeO4. Substitution of S with Se in the Cd(NCX)2(nia)2 (X = Se or S) caused an increase of Cd translocation into the shoots.
Presented at the XVIIIth Slovak Spectroscopic Conference, Spišská Nová Ves, 15–18 October 2006. 相似文献
112.
František Kvasnička Jaroslav Dobiáš Kamila Klaudisová-Chudáčková 《Central European Journal of Chemistry》2003,1(1):91-97
A simple, rapid and reproducible capillary isotachophoretic on-line coupled with capillary zone electrophoresis (CITP-CZE)
method for the determination of IMz in food packaging extracts and its residues in apples is described. A good separation
of the IMZ from other sample constituents was achieved within 15 minutes without any sample clean up. Method characteristics
(linearity, accuracy, intra-assay and detection limit) were determined. Less amount of time involved, sufficient sensitivity
and low running cost are the important attributes of CITP-CZE method. 相似文献
113.
Nataša Pejić Slobodan Anić Vesna Kuntić Vladana Vukojević Ljiljana Kolar-Anić 《Mikrochimica acta》2003,143(4):261-267
A kinetic method is described for the microquantitative (microconcentration/microvolume) determination of rutin based on potentiometric monitoring of the concentration perturbations of the Bray-Liebhafsky (BL) oscillatory reaction being in a non-equilibrium stationary state close to a bifurcation point. The experiments are carried out in an open reactor. The response of the matrix system to perturbations by different concentrations of rutin ethanolic solutions is followed by a Pt-electrode. In the concentration range between 7.8×10–8moldm–3 and 9.1×10–6mol dm–3, we found a linear dependence of the maximal potential shift, Em, on the logarithm of the rutin concentrations. The unknown concentrations can be determined from the calibration curve up to an accuracy of ±5%. The detection limit is 3.6×10–8mol dm–3. The amount of required sample can be as small as 10µL. 相似文献
114.
P. Rajec F. Macášek M. Féder P. Misaelides E. Šamajová 《Journal of Radioanalytical and Nuclear Chemistry》1998,229(1-2):49-55
The sorption of caesium and strontium from its aqueous solutions by ten clinoptilolite-and mordenite-containing sedimentary
materials from Slovakia, Bulgaria, Ukraine and Greece was investigated by batch-type procedure and radiotracer techniques.
The concentration of the solutions, that were performed in and without the presence of competing cations (0.005 mol·dm−3 KCl) varied between 1·10−4 and 5·10−2 mol·dm−3. The uptake and distribution coefficient (K
d
) values determined for the materials of the different origin, were correlated with their mineralogical composition and gross
cation exchange capacity (CEC). The identification of the specific uptake sites was attempted on the basis of the sorption
isotherms and the content of exchangeable cations. The experimental results provide information on the suitability of the
individual materials for the treatment of radioactive wastes and their application as backfills in potential nuclear waste
repositories. 相似文献
115.
The kinetics of the dehydration of CsNd(SO4)2 · 4 H2O to CsNd(SO4)2 · H2O and then to CsNd(SO4)2 are studied by isothermal weight change. The reactions are phase-boundary-controlled. Reaction mechanism and activation energy depend on sample weight. 相似文献
116.
The construction of the Z-counting polynomial for edge-weighted graphs is discussed.Dedicated to Professor Haruo Hosoya (Tokyo) on the occasion of his 55th birthday for enriching chemical graph theory with the elegant concept of the Z-counting polynomial. 相似文献
117.
David Bevk Uroš Grošelj Anton Meden Jurij Svete Branko Stanovnik 《Helvetica chimica acta》2007,90(9):1737-1744
A simple and efficient synthesis of four new substituted pyrimidines, compounds 9a – d , from the title compound 3 is described. Conversion of 3 to methyl (E)‐3‐(dimethylamino)‐2‐(6‐methoxy‐2‐phenylpyrimidin‐4‐yl)prop‐2‐enoate ( 4 ), followed by condensation with various dinucleophiles according to the ‘enaminone methodology’, afforded the target compounds 9 in medium‐to‐good yields. 相似文献
118.
Equilibrium and kinetic studies of ion exchange of a complex leach liquor from coal ash, with strongly basic resins and a liquid ion exchanger are reported. The multi-component system was studied by determining the composition of the effluents and by non-destructive analysis of the loaded ion exchangers by XRF spectrometry. In the case of column operation, the elution processes were investigated by the same method, which was very appropriate for non-destructive monitoring of resin regeneration steps done repeatedly with the same resin sample. 相似文献
119.
Tomislav Došlić 《Journal of mathematical chemistry》1998,24(4):359-364
Couting perfect matchings in graphs is a very difficult problem. Some recently developed decomposition techniques allowed us to estimate the lower bound of the number of perfect matchings in certain classes of graphs. By applying these techniques, it will be shown that every fullerene graph with p vertices contains at least p/2+1 perfect matchings. It is a significant improvement over a previously published estimate, which claimed at least three perfect matchings in every fullerene graph. As an interesting chemical consequence, it is noted that every bisubstituted derivative of a fullerene still permits a Kekulé structure. 相似文献
120.
The thermal behaviour of N2H6GeF6 · H2O was investigated by TG, DTG and DTA measurements. The decomposition proceeded in three steps, in which anhydrous N2H6GeF6 and N2H5GeF5; were isolated and characterized by chemical analysis and vibrational spectroscopy. The X-ray powder photographs of the intermediates were indexed, namely, for N2H6GeF6 on the basis of a monoclinic cell with a = 8.86(9), b = 9.29(2), c =7.40(0) Å, β = 85° and for N2H5GeF5 on the basis of an ortrhorhombic cell with a = 8.43(5),b = 9.19(9), c = 7.43(6) Å. 相似文献