• Applied Chemistry for Engineering
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• v.24 no.1
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• pp.44-48
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• 2013

In this work, we have prepared tungsten doped vanadium oxide ($W-VO_2$) particles with a low phase transition temperature. $W-VO_2$ particles were synthesized via thermolysis method using vanadyl (IV) sulfate and ammonium bicarbonate as precursors. The structure and thermochromic property of synthesized $W-VO_2$ particles were investigated by FE-SEM, EDS, XRD, XPS, and DSC analysis. The prepared $W-VO_2$ showed a nearly platy morphology, which indicates that the tungsten was successfully doped in the crystal lattices of $VO_2$. $W-VO_2$ nanoparticles with the size of 60 nm exhibited a monoclinic crystal structure and its chemical composition and surface state were also likely to be close to that of $VO_2$. In addition, the phase transition temperature of $W-VO_2$ was $38.5^{\circ}C$, which was approximately $29.2^{\circ}C$ lower than that of pure $VO_2$ ($67.7^{\circ}C$), indicating that the prepared sample had a good reversible thermochromic stability.

• Journal of the Korean Chemical Society
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• v.54 no.4
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• pp.395-401
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• 2010

A series of macrocyclic complexes of the type [M(L/L')$(NO_3)_n$].$mH_2O$ and [VO(L/L')($SO_4$)].$2H_2O$, where L/L' is a Schiff base "3,4,10,11-tetraphenyl/tetramethyl-1,2,5,6,8,9,12,13-octaaza cyclotetradeca-2,4,9,11-tetraene-7,14-dithione" derived from thiocarbohydrazide (TCH), benzilmonohydrazone (BMH)/diacetylmonohydrazone (DMH) and carbon disulphide, M = $UO_2$ (VI), Th(IV) and ZrO(IV), n = 2, 4, m = 2, 3, have been synthesized via metal ion template methods. The complexes are characterized on the basis of elemental analysis, thermal analysis, molar conductivity, magnetic moment, electronic, infrared and $^1H$-NMR spectral studies. The ESR and cyclic voltammetry studies of the vanadyl complexes have been carried out. The results indicate that the VO(IV) ion is penta-coordinated yielding paramagnetic complexes; $UO_2$(VI) and ZrO(IV) ions are hexacoordinated where as Th(IV) ion is octa-coordinated yielding diamagnetic complexes of above composition.

• KSBB Journal
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• v.19 no.6 s.89
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• pp.471-477
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• 2004

Oldenlandia diffusa is a Chinese medicinal herb with antitumor activity capable of suppressing the growth of some cancer cell lines. Oleanolic acid and ursolic acid are triterpenoid compounds that exist in Oldenlandia diffusa. Recently, these have been noted for anti-inflammatory, anti-cancer, and hepato-protective effects. Application of both plant growth regulators, 2,4-D and kinetin, was found to be essential for the initiation of callus and suspension cells. Leaf blades of Oldenlandia diffusa was transformed into callus on Schenk and Hildebrandt medium supplemented with 0.5 mg/L 2,4-D and 0.1 mg/L kinetin, while optimum initiation condition for suspension cells of Oldenlandia diffusa was determined to be 0.75 mg/L 2,4-D and 0.1 mg/L kinetin. Chromatographic separation of oleanolic acid from its derivatives was achieved using Rexchrom S5-100-ODS column. Analytical conditions for oleanolic acid were determined as follows: flow rate at 1.0 mL/min, UV length at 200 nm and mobile phase of $80\%$ acetonitrile and $20\%$ water. Production of secondary metabolites was found to be increased by the treatment with elicitors or signal transducers. The maximum production of oleanolic acid was 99.6 mg/L in cultures with 0.5 mM salicylic acid. It is 1.74 times higher than that of control.