Papers by Keyword: Silicate

Abstract: A series of luminescence phosphors M_0.955Al_{2 –x}Ga_xSi₂O₈∶Eu²⁺ (M=Ca, Sr, Ba, x = 0~1.0) were prepared via solid-state reaction in weak reductive atmosphere. The lattice positions were discussed. It was found that when Ga³⁺ entered MAl₂Si₂O₈ lattice and substituted Al³⁺, complete solid solutions formed. The lattice parameters (a, b, c) and unit cell volume of phosphors M _0.955Al_{2 –x}Ga_xSi₂O₈: Eu²⁺ (M=Ca, Sr, Ba, x = 0~1.0) increased linearly, the lattice parameters (α, β,γ) of Ca_0.955Al_2–xGa_xSi₂O₈∶Eu²⁺(CAS) decreased linearly and the lattice parameter β of Sr_0.955Al_2–xGa_xSi₂O₈∶Eu²⁺(SAS) and Ba_0.955Al_2–xGa_xSi₂O₈∶Eu²⁺(BAS) increased linearly as Ga³⁺ content increased.

Abstract: M₂SiO₄: Tb³⁺, Mn²⁺, Nd³⁺ (M = Mg²⁺, Ca²⁺, Sr²⁺, and Ba²⁺) phosphors suitable for near-ultraviolet-violet radiation excitation were successfully prepared at 1400 °C in N₂ atmosphere by a high-temperature solid-state reaction, and their phase compositions and luminescent performance were also studied by X-ray diffraction (XRD), photoluminescence spectra. Results show that their emission intensity increases in the order of Ca₂SiO₄ > Mg₂SiO₄ > Sr₂SiO₄ > Ba₂SiO₄ matrix phosphor. Ca_1.94SiO₄: 0.02Tb^{3 +}, 0.02Mn²⁺, 0.02Nd²⁺ phosphor exhibits the best luminescence performance.

Abstract: The essence of the hydraulic fracturing method for enhancing oil recovery is described. The definition of proppants is given and their average chemical composition is determined. In the process of an analytical review, the article presents proppants that are widely used in the oil industry. For each type of proppant, the main technical characteristics (bulk density and compressive strength) required when using the hydraulic fracturing method have been determined. In the course of the analysis, it was found that all proppant technologies are expensive and it is necessary to select high-quality cheap and affordable materials to reduce the cost of their production. Drilling cuttings from the Morozovskoye field were chosen as one of these materials. Physical and chemical studies of drill cuttings were carried out, on the basis of which a conclusion was made about the possibility of its use in the synthesis of high-quality aluminosilicate proppants.

Abstract: Whether silicate-substituted strontium apatite (SrSiP) stimulates osteogenesis on the surface of implants has been evaluated in the present study. Polyether ether ketone (PEEK) disks were coated with a nanocrystalline SrSiP dispersion using CO₂ laser irradiation. At approximately 300°C, the coating layer of SrSiP was tightly adhered to the surface of PEEK disks. The SrSiP-coated PEEK showed excellent bioactive properties when bone marrow-derived mesenchymal stem cells were cultured on the PEEK disks, when compared to the untreated PEEK disks.

Abstract: Well-grown Ba₉Sc₂Si₆O₂₄:Ce³⁺ phosphors were synthesized by a novel melt quenching synthesis method. Sintered phosphor balls with excellent luminescent characteristics were obtained. This method is useful tool for rapid screening of phosphor materials.

Abstract: Based on the theory of ecological resources recycling, the effects of matrix quality, surface treatment method, soaking time, age after treatment and fluosilicate cation on hardening cement based materials were investigated by using the byproduct of phosphate fertilizer production namely fluosilicate as the surface treatment agent of cement-based materials and changing different surface treatments. The results showed that the permeation capacity of surface hardener solution , the wear resistance and surface hardness of cement-based materials were significantly improved by the treatments of surface sanding and oven drying. Both surface spraying and submerging methods can promptly increase the hardening effect by more than 20%, manifesting as the rapid improvement of wear resistance in 1 day and the maintenance of that in 7 days. The effective spraying amount and soaking time were 100g/m²-200g/m² and 6 h, respectively. The fluosilicate surface hardener exhibited better hardening effect than the silicate surface hardener for those matrix materials with different quality, especially for the matrix materials with low compactness. The magnesium fluosilicate displayed the best hardening effect. Besides, the mechanism of fluosilicate and silicate surface hardeners were discussed and compared. The results show that the fluosilicate surface hardener produced crystals and colloids by reacting with cement hydrates to fill the void and improve the compactness, other than the silicate surface hardener which produced calcium silicates by reacting with cement hydrates. As a result, the hardness and wear resistance of cement-based materials are improved, but also the probability of a potential alkali-aggregate reaction is substantially reduced.

Abstract: Well-grown M₃MgSi₂O₈ (M = Ca, Sr and Ba):Eu²⁺ phosphors were synthesized by novel melt quenching synthesis method. The luminescence property of the Sr₃MgSi₂O₈:Eu²⁺ phosphor synthesized by the melt synthesis method is comparable to those of the sample synthesized by a conventional solid state reaction. Sintered phosphor balls with excellent luminescent characteristics were obtained.

Abstract: Silicate-containing alpha-tricalcium phosphate (α-TCP) ceramics are expected to be useful scaffolds for bone regeneration because α-TCP shows high biodegradability and silicate ions are expected to promote the bone formation. We previously revealed that the porous silicate-containing α-TCP granules provided earlier bone formation and showed lower biodegradability than the porous silicate-free α-TCP granules in vivo. In order to reveal the mechanism of the bone formation promoted by silicate incorporation, the proliferation and differentiation of osteoblast-like cells on the silicate-containing and silicate-free α-TCP ceramics were examined in vitro. The silicate incorporation in α-TCP promoted the differentiation of osteoblast-like cells, and it might be one of the factors to promote bone formation In Vivo.

Abstract: The paper presents the results of research focused on modification of silicate matrix by secondary energy products with current reinforcement using carbon nanotubes (CNT). A suitable CNT sorting method was assessed first. In the following, the influence of various composition of the blended binder (substitution of cement in quantities 15, 25 and 35 %) of reinforced CNT to basic parameters and micro structure was examined. Amphibolite was used as a filling agent. Temperature exposition took its course up to 1,200 °C with consecutive controlled cooling.

Abstract: This paper contains the continuation of basic research from 2012 - the molar ratio influence to water glass coatings basic properties (adhesion, diffusion properties, surface quality) was expanded with basic resistance (combination of sun, UV light and rain). Most silicate coatings for concrete protection are currently based on potassium water glass. Water glass matrix itself is, however, insufficient for coatings matrix and often is modified by polymer substances for the coating purpose. Combinations of water glass basic matrix (Sodium, Potassium, Lithium, Sodium - Lithium and Potassium - Lithium) with the appropriate polymer modifiers is also content of the presented paper. Polymer dispersions modification effect to basic properties and resistance to developed silicate coating binder is also part of paper.