http://tainguyenso.vnu.edu.vn/jspui/handle/123456789/6538 Tue, 19 May 2026 21:48:11 GMT 2026-05-19T21:48:11Z http://tainguyenso.vnu.edu.vn/jspui/handle/123456789/6617 Title: Luminescent nanomaterials containing rare earth ions for security printing Authors: Anh, T.K.; Loc, D.X.; Huong, T.T.; Vu, N.; Minh, L.Q. Abstract: The high-efficiency luminescent nanomaterials with different emission wavelengths of red (YVO4 :Eu3+), green (CePO 4:Tb3+), ZnS:Mn2+ and YVO4:Eu 3+@SiO2 were successfully prepared with different concentrations of Mn and rare earth ions as active centres by chemical synthesis. Structure properties were studied. It was found that the particle size of our samples was in the range of 10-30 nm. Photoluminescent properties were studied under 325, 337, 365 and 370 nm excitations in order to apply in luminescent labels. The primary colour components are red and green emission making them very convenient and attractive for screen security printing systems. Hundreds of different labels with a size of 1- 10 cm2 were prepared by screen-printing as well as inkjet printing. By improving the Epson printer, commercial red, green and blue inks were used in the printing application. Screen and inkjet printing were deemed good methods for security printing. Our products were beautiful, high resolution and withstood tropical weather. Copyright ?? 2011 Inderscience Enterprises Ltd. Sat, 01 Jan 2011 00:00:00 GMT http://tainguyenso.vnu.edu.vn/jspui/handle/123456789/6617 2011-01-01T00:00:00Z http://tainguyenso.vnu.edu.vn/jspui/handle/123456789/6613 Title: Dynamics of Kolmogorov systems of competitive type under the telegraph noise Authors: Du, N.H.; Dang, N.H. Abstract: This paper studies the dynamics of Kolmogorov systems of competitive type under the telegraph noise. The telegraph noise switches at random two Kolmogorov competition-type deterministic models. The aim of this work is to describe the omega-limit set of the system and investigates properties of stationary density. ?? 2010 Elsevier Inc. Sat, 01 Jan 2011 00:00:00 GMT http://tainguyenso.vnu.edu.vn/jspui/handle/123456789/6613 2011-01-01T00:00:00Z http://tainguyenso.vnu.edu.vn/jspui/handle/123456789/6610 Title: Optical properties of Mn-doped ZnS semiconductor nanoclusters synthesized by a hydrothermal process Authors: Hoa, T.T.Q.; The, N.D.; McVitie, S.; Nam, N.H.; Vu, L.V.; Canh, T.D.; Long, N.N. Abstract: Undoped and Mn-doped ZnS nanoclusters have been synthesized by a hydrothermal approach. Various samples of the ZnS:Mn with 0.5, 1, 3, 10 and 20 at.% Mn dopant have been prepared and characterized using X-ray diffraction, energy-dispersive analysis of X-ray, high resolution electron microscopy, UV-vis diffusion reflection, photoluminescence (PL) and photoluminescence excitation (PLE) measurements. All the prepared ZnS nanoclusters possess cubic sphalerite crystal structure with lattice constant a = 5.408 ? 0.011 . The PL spectra of Mn-doped ZnS nanoclusters at room temperature exhibit both the 495 nm blue defect-related emission and the 587 nm orange Mn2+ emission. Furthermore, the blue emission is dominant at low temperatures; meanwhile the orange emission is dominant at room temperature. The Mn2+ ion-related PL can be excited both at energies near the band-edge of ZnS host (the UV region) and at energies corresponding to the Mn2+ ion own excited states (the visible region). An energy schema for the Mn-doped ZnS nanoclusters is proposed to interpret the photoluminescence behaviour. ?? 2010 Elsevier B.V. All rights reserved. Sat, 01 Jan 2011 00:00:00 GMT http://tainguyenso.vnu.edu.vn/jspui/handle/123456789/6610 2011-01-01T00:00:00Z http://tainguyenso.vnu.edu.vn/jspui/handle/123456789/6604 Title: Synthesis and characterization of unusual oxidorhenium(V) cores Authors: Nguyen, H.H.; Hazin, K.; Abram, U. Abstract: Reactions of (NBu4)[ReOCl4] with N-(N??, N??-dialkylaminothiocarbonyl)-N?-(2- hydroxyphenyl)benzamidines (H2L1) give complexes of the compositions [ReOCl(L 1)] (1), cis-[ReO(L1 )(OMe)] (2), or cis,cis-[{ReO(L 1)}2O] (3) depending on the conditions applied. Compound 3 contains a bridging oxygen atom in the cis position to the terminal oxido ligands of both rhenium atoms. The analogous dimeric, sulfur-bridged compound [{ReO(L1)}2S] (4) was obtained by the reaction of 1 with Na2S. Complexes with the unusual oxidorhenium(V) cores, cis-{ReO(OR)}3+, cis,cis-{ORe-O-ReO}4+, and cis,cis-{ORe-S-ReO}4+, are formed from the reaction of [ReOCl 4]- and N-(N??,N??- dialkylaminothiocarbonyl)- N?-(2-hydroxyphenyl)benzamidine ligands depending on the conditions applied. Copyright ?? 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Sat, 01 Jan 2011 00:00:00 GMT http://tainguyenso.vnu.edu.vn/jspui/handle/123456789/6604 2011-01-01T00:00:00Z