32 Result(s)
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Article
Thermal stability and cathodoluminescence of potassium strontium vanadates
We have studied the thermal stability of five potassium strontium vanadates: KSr(VO3)3, K2Sr(VO3)4, K4Sr(VO3)6, K6Sr(VO3)8, and KSrVO4. The double orthovanadate undergoes a reversible polymorphic transformation a...
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Article
Hexametavanadates M 4 + M2+(VO3)6: Thermal stability and luminescent characteristics
Rhombohedral hexametavanadates K4Sr(VO3)6, K4Ba(VO3)6, Rb4 Ba(VO3)6, and Cs4Ba(VO3)6 melt incongruently in the temperature range of 491 to 600°C. Cooling of peritectic melts yields mixtures of compounds typical o...
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Article
Thermochemical and luminescent properties of the K2MgV2O7 and M2CaV2O7 (M = K, Rb, Cs) vanadates
We have studied the compounds K2MgV2O7 and M2CaV2O7 with M = K, Rb, and Cs. These vanadates melt incongruently in the range 635–717°C. Cooling their decomposition products to room temperature leads to the formati...
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Article
Thermochemical and luminescent properties of RbVO3, CsVO3, and Rb0.5Cs0.5VO3
RbVO3, CsVO3, and Rb0.5Cs0.5VO3 have been synthesized by the Pechini process. The vanadates have an orthorhombic structure (sp. gr. Pbcm), melt congruently in the range 650–530°C, and undergo a reversible phase t...
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Article
Structure and luminescent properties of Cs2Sr(VO3)4:Mn2+
We have developed a procedure for thermally stimulated synthesis of a cesium strontium metavanadate, Cs2Sr(VO3)4:Mn2+ (0.01, 0.50, 1.00, 5.00 at % Mn2+), using MnO-containing starting mixtures. The EPR spectrum o...
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Article
Synthesis and cathodoluminescence characteristics of europium-doped Ca-sialons
Using solid-state reactions and a combination of carbothermal reduction-nitridation with solgel processing, we have synthesized a number of oxynitride phases: Eu2+-doped Ca-sialons. We have measured the pulsed ca...
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Article
Thermolysis of copper(II) salts of maleic acid. Synthesis of metal-polymer composites
The thermal decomposition of neutral ([Cu(H2O)(C4H2O4)]) and acidic ([Cu(H2O)4](C4H3O4)2) maleates can conventionally be divided into four stages: (1) dehydration, (2) polymerization, (3) isomerization of the mal...
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Article
Thermal and luminescent properties of M2Zn(VO3)4 (M = Rb, Cs)
We have developed processes for the synthesis of the Rb2Zn(VO3)4 and Cs2Zn(VO3)4 tetrametavanadates. Rb2Zn(VO3)4 has been prepared by solid-state reaction (350°C) between presynthesized RbVO3 and ZnV2O6 powders, ...
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Article
Preparation of metal-polymer composites through the thermolysis of Fe(II), Co(II), and Ni(II) maleates
Metal-polymer composites have been prepared through the thermolysis of the [M1(H2O)2(C4H2O4)] · H2O (M1 = Co(II), Ni(II)) neutral maleates and [M2(H2O)4(C4H3O4)2] (M2 = Fe(II), Co(II), Ni(II)) acid maleates. In t...
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Article
Preparation and luminescent properties of rubidium and cesium vanadates
Four rubidium and cesium vanadates, with the compositions Rb5V3O10, Rb3V5O14, Cs5V3O10, and Cs2V4O11, have been synthesized and identified, and their thermal stability ranges have been determined. Their spectrosc...
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Article
Change in sizes of carbon aggregates and primary particles of the onion-like carbon synthesized by high-temperature annealing of nanodiamond
Changes in the sizes of nanodiamond (ND) aggregates in the course of preparation of the onion-like carbon (OLC) by high-temperature annealing in vacuo were studied. The main regularities of its formation were rev...
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Article
A small-angle x-ray scattering study of the nanostructural features of high-ash carbon materials
Nanostructured carbon-silica composite materials are prepared from different compounds in one-pot. They are characterized by BET, transmission electron microscopy, X-ray diffraction, and small-angle X-ray scat...
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Article
Preparation of a copper-polymer composite through the thermolysis of copper(II) succinate
A procedure has been proposed for the preparation of copper/polymer composites through Cu(C4H4O4) · H2O succinate thermolysis. Three types of copper nanoparticles have been incorporated into a fibrous carbon-poly...
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Article
A tem study of MoVTe(Nb) oxide catalysts for the selective conversion of propane
The structure of X-ray amorphous precursors of MoVTeO and MoVTeNbO oxide catalysts and their conversion at high-temperature treatment and under exposition in the reaction medium is studied by analytical transm...
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Article
Maleates of Mn(II), Fe(II), Co(II), and Ni(II) as precursors for synthesis of metal-polymer composites
Comparison was made for the structural, IR spectral, and thermoanalytical characteristics of normal [M1(H2O)2(C4H2O4)](H2O) (M1 = Co(II) and Ni(II)) and acid maleates [M2(H2O)4(C4H3O4)2] (M2 = Mn(II), Fe(II), Co(...
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Article
Effect of dopant concentration on the phase composition and luminescence properties of Eu2+- and Ce3+-doped AlONs
Herein we report the synthesis of aluminum oxynitride (Al5O6N) doped with Eu2+ and Ce3+ and examine the effects of the dopant concentration and the nature of the rare-earth-containing precursor (europium and ceri...
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Article
In situ powder X-ray diffraction study of the process of NiMoO4–SiO2 reduction with hydrogen
An interest in NiMoО4–SiO2 reduction stems from its promising use as catalysts for hydrodeoxygenation and hydrodesulfurization processes. The work exploits in situ X-ray diffraction to investigate phase transform...
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Article
Towards the optimization of carbon nanotube properties via in situ and ex situ studies of the growth mechanism
The synthesis conditions of multi-walled carbon nanotubes (MWCNTs) indirectly determine their application potential through the decisive role in the characteristics of individual tubes: diameter distribution, ...
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Article
The effect of the synthesis method on the morphological and luminescence characteristics of α-Zn2V2O7
A promising yellow phosphor, α-Zn2V2O7, was synthesized at temperatures below the phase transition temperature (610 ± 5°C) by three different methods: solid-phase and microwave processes and thermolysis of a wate...
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Article
Sol–gel synthesis of 2D and 3D nanostructured YSZ:Yb3+ ceramics
This paper presents results of a detailed study of fundamental aspects of the formation of 2D and 3D nanostructured YSZ:Yb3+ ceramics with a cubic structure through a key synthesis step in aqueous solutions of zi...
