排序方式: 共有55条查询结果,搜索用时 156 毫秒
21.
Reactivity of FeVO4 towards Ni2V2O7 and Ni3V2O8 in the solid state was investigated. On the base of XRD and DTA results, phase diagrams in subsolidus area of the FeVO4-Ni2V2O7 and FeVO4-Ni3V2O8 intersections of the ternary system NiO-V2O5-Fe2O3 have been worked out and the phase diagram of this ternary system in subsolidus area in the whole component concentration
range has been verified.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
22.
J. Walczak J. Ziołkowski M. Kurzawa L. Trzesniowska 《Journal of Thermal Analysis and Calorimetry》1984,29(5):983-988
Phase équilibria have been investigated in the FeVO4-Fe2(MoO4)3 system for the whole concentration range of the components. In this system there is one compound which melts incongruently: Fe4V2Mo3O20. The results are presented in the form of a phase diagram.
Zusammenfassung Phasengleichgewichte im System FeVO4-Fe2(MoO4)3 wurden über den ganzen Konzentrationsbereich der Komponenten hinweg untersucht. Eine Verbindung des Systems, Fe4V2Mo3O20, schmilzt inkongruent. Die Ergebnisse sind in Form eines Phasendiagramms angegeben.
FeVO4-Fe2(MoO4)3 . Fe4V2Mo3O20, . .相似文献
23.
The phase equlibria established in the Zn3V2O8–ZnMoO4 system over the whole component concentration range up to 1000°C have been investigated. A phase diagram has been constructed
using the results of DTA and XRD methods.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
24.
Filipek E. Kurzawa M. Dąbrowska G. 《Journal of Thermal Analysis and Calorimetry》2001,64(3):1105-1111
DTA and XRD methods used to examine the Cr2O3–α-Sb2O4–MoO3 system have shown that a substitution solid solution of MoO3 in CrSbO4 is formed. A study of all the theoretically possible solid solution models has pointed to the fact that Mo6+ ions are incorporated into the CrSbO4 crystal lattice, in the place of Sb5+ ions and the compensation of redundant charges takes place through cation vacancies arising in an Sb5+ sub-lattice. The solubility limit for MoO3 in CrSbO4 does not exceed 25.00 mol%. CrSbO4(s.s.) is stable to ~1320°C.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
25.
DTA and XRD methods were applied in studies on phase equilibria established in the system V9Mo6O40-AlVMoO7 up to 1000°C over the whole component concentration range. The results were presented in the form of a phase diagram.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
26.
Ohne Zusammenfassung
Determination of micro-amounts of cobalt as pyrrolidinedithiocarbamate using the reaction of iodine with sodium azide相似文献
27.
The neutron diffraction patterns of Mg2FeV3O11-δ compound at various low temperatures have been investigated. No magnetic ordering was observed in the investigated temperature range down to 10K. These materials have been formed in the triclinic space group but there are specific differences in the positions of atoms as compared to previously determined from XRD method. The iron(III) ions are distributed non-statistically with magnesium(II) ions and this could be responsible for some differences in the structure of the above sample. The method of sample preparation, in particularly thermal annealing processes could be responsible for the differences. 相似文献
28.
Anna Filipiak-Szok M. Kurzawa E. Szłyk M. Twarużek A. Błajet-Kosicka J. Grajewski 《Chemical Papers》2017,71(6):1073-1082
Mycotoxins and selected hazardous alkaloids in the medicinal plants (Panax ginseng, Angelica sinensis, and Withania somnifera) and dietary supplements were determined. Purine alkaloids were found in majority of samples; however, isoquinoline alkaloids were less abundant than indole. The predominant alkaloids appear to be caffeine (purine group), harman (indole group) and berberine (isoquinoline). Examined medicinal plants and dietary supplements were contaminated by mycotoxins (especially ochratoxin A 1.72–5.83 µg kg?1), and many species of mold (e.g. Cladosporium, Eurotium, Aspergillus, Rhizopus, Penicillium). MTT cytotoxicity tests revealed that plant and supplements extracts exhibited medium or high cytotoxicity (only Dong quai—low). Moreover, antioxidant activity, total phenolics content and selected phytochemicals were analyzed by spectrophotometric and chromatographic methods. Quercetin and rutin were predominant flavonols (1.94-9.51 and 2.20–7.28 mg 100 g?1, respectively). Analysis of phenolic acids revealed—gallic acid, as the most abundant, except Panax ginseng, where ferulic acid was prevailing. The results were analyzed by chemometric methods (cluster analysis, ANOVA). 相似文献
29.
Aneta Jastrzębska Marzanna Kurzawa Paweł Hrynczyszyn Edward Szłyk 《Journal of Analytical Chemistry》2012,67(2):172-178
A two-dimensional capillary isotachophoretic method (cITP-cITP) using electrolyte system consisting of leading electrolytes (LE1): [10 mM HCl + β-alanine (pH 3.9) + 0.1% hydroxyethylcellulose (HEC)] and (LE2): [10 mM HCl + aminocaproic acid (pH 5.00) + 0.1% HEC], and 5 mM caproic acid as terminating electrolyte (TE) was studied. Two methods of detection, conductometric and UV-Vis, were applied to the determination of selected food preservatives
and additives. Practical applicability was demonstrated by simultaneous determination of benzoates, sorbates, citrates and
orthophosphates in 12 samples of beverages. The proposed method revealed linearity with R
2 between 0.9992 and 0.9999 for the concentration ranges: 10–100 mg/L (orthophosphate and citrate ions), 20–100 mg/L (sorbates)
and 40–120 mg/L for benzoates. The detection limits for all studied ions were from 0.85 to 3.1 mg/L whereas the quantification
ones were from 2.8 to 10 mg/L. The variation coefficients for five-fold analysis of all ions ranged between 0.4 and 9.1%.
Obtained recoveries (from 97 to 104%) confirmed satisfactory accuracy of the proposed cITP-cITP method for the determination
of tested food additives. 相似文献
30.
Phenolic acids and derivatives of quercetin in Indian (amla) and European gooseberry were determined by high-performance liquid
chromatography with diode array detector. The calibration curves were constructed using phenolic compounds standards (the
coefficient of determination (R
2) was 0.9990–0.9997 for phenolic acids and 0.9989–0.9994 for flavonols, respectively). The lowest detection limit was 0.28
mg L−1 and 0.35 mg L−1 for hyperoside and gallic acid, respectively, whereas the highest was 1.80 mg L−1 and 7.98 mg L−1 for quercetin and chlorogenic acid, respectively. The quantification limits calculated were 0.85–24.04 mg L−1 for hyperoside and chlorogenic acid, respectively. The predominant phenolic acid in amla and gooseberry is gallic acid: (5.37
± 0.04) mg per 100 g of dry mass (d.m.) and (3.21 ± 0.03) mg per 100 g of d.m., respectively. The next one was caffeic acid,
0.65–1.22 mg per 100 g of d.m., followed by p-coumaric acid, 0.84–1.17 mg per 100 g of d.m. Out of the flavonols, rutin is predominant: (3.11 ± 0.13) mg per 100 g of d.m.
and (2.12 ± 0.03) mg per 100 g of d.m., respectively. Anti-oxidant activity was also determined. 相似文献