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Wyniki wyszukiwania dla: silica
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Application of differential scanning calorimetry to study porous structure of hydrothermally modified silicas
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Ionic conductivity in bismuth silicate glasses.
PublikacjaZbadano właściwości elektryczne szkieł krzemianowo- bizmutowych zawierających 55 mol% tlenku bizmutu. Uzyskane wyniki potwierdzają jonowy charakter przewodnictwa, za które odpowiedzialne są jony tlenu.
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Characterization of Multimodal Silicas Using TG/DTG/DTA, Q-TG, and DSC Methods
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Improvement of photocatalytic activity of silicate paints by removal of K2SO4
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Yb3+/Ho3+-codoped antimony-silicate optical fiber
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Nd3+/Yb3+energy transfer in oxyfluoride silicate glass
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Bismuth germanate and bismuth silicate glasses in cryogenic detectors.
PublikacjaStwierdzono, że przewodnictwo elektryczne redukowanych szkieł silnie zależy od temperatury, czasu reakcji i koncentracji Bi. Zależność przewodnictwa elektrycznego od temperatury jest dobrze opisana przez funkcję ĺ~exp[-(T0/T)n,gdzie n=1/4. Współczynnik emisji wtórnej elektronów jest praktycznie niezależny od stopnia redukcji ale znacznie rośnie po domieszkowaniu szkieł alkalicznymi jonami. Badania dowiodły, że modyfikowane...
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Ionic conductivity of bismuth silicate and bismuth germanate glasses.
PublikacjaPrzedstawiono wyniki badań przewodnictwa d.c i a.c. szkieł BixGe1-xO2-0.5x (gdzie x=0.13, 0.23, 0.33, 0.47) i BixSi1-xO2-0.5x (gdzie x=0.47, 0.57, 0.67). Wyniki sugerują, że przewodnictwo elektryczne jest zdeterminowane ruchem jonów tlenu. Znaczący wzrost przewodnictwa elektrycznego przy x> 0.33 został wytłumaczony na podstawie faz perkolacyjnego modelu ruchu jonów w podsieci BiO5-6.
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Evaluation of dampness-induced strength reduction of calcium silicate blocks
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Rigid polyurethane foams modified with selected layered silicate nanofillers
PublikacjaThe aim of this study was to investigate the effect of three different nanofillers on the properties of rigid polyurethane foams, which were prepared by a one-step, laboratory-scale method from a two-component system at the ratio of NCO groups to OH groups equaled to 2. The reaction mixture consisted of the proper amounts of the commercial oligoether polyol, catalysts, water, nanoclays, and polymeric diphenylmethane diisocyanate....
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Characterization of structural, thermal and mechanical properties of bismuth silicate glasses
Publikacjahe influence of heating and reduction processes on the structural, thermal and mechanical properties of bismuth-silicate glasses has been investigated. Two compositions of glasses: 40Bi2O3–60SiO2 (Bi0.57Si0.43Ox) and 27Bi2O3–73SiO2 (Bi0.43Si0.57Ox) were fabricated by a typical melt quenching technique. Then the reduction in hydrogen at 380 °C for 20, 42 or 67 h was performed. It was found that a 50 μm-thick layer was formed on...
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The influence of Be addition on the structure and thermal properties of alkali-silicate glasses
PublikacjaBe-Na-(Li)-Si oxide glasses containing up to 15 mol% of BeO were prepared. Their structure was characterized by X-ray powder diffraction and Raman as well as infrared spectroscopic techniques, while their chemical compositions were examined by Inductively Coupled Plasma Optical Emission Spectrometry. All materials were found to be amorphous and contain Al contaminations from minor dissolution of the alumina crucibles. The results...
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Niobate in silicate and phosphate glasses: Effect of glass basicity on crucible dissolution
PublikacjaUsing niobium crucibles for melting phosphate and silicate glasses of various modifier oxide contents, and therefore varying optical basicity (Λ), was found to result in varying dissolution rates of niobate during melting. Because of their high electronic polarizability, even small concentrations of niobates are detectable in the Raman spectra of glasses. Even less than 1 mol% Nb2O5 can be identified, as independently confirmed...
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Epitoanyag-Journal of Silicate Based and Composite Materials
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The oxidation of limonene at raised pressure and over the various titanium-silicate catalysts
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Structural and optical study on antimony-silicate glasses doped with thulium ions
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Effect of short time reduction on electrical properties of bismuth-silicate glasses
PublikacjaPodczas krótkiego wygrzewania szkieł bizmutowo-krzemianowych w wodorze (około 5 min w 375C) przewodnictwo powierzchniowe wzrasta o kilka rzędów wartości. Nośnikiem ładunku w tych próbkach jest hopping elektronowy między zlokalizowanymi stanami w badanej warstwie krzemu, zawierającej małe klastry Bi. Wpływ granul bizmutu na przewodnictwo jest widoczny w drugim stadium redukcji, które zachodzi po redukcji dłuższej niż 4h.
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EXAFS analysis of bismuth atom neighbourhood in reduced bismuth silicate glass
PublikacjaPraca zawiera wyniki strukturalnej analizy EXAFS niemodyfikowanego szkła bizmutowo-krzemianowego o składzie 0.4Bi2O3 0.6SiO2 oraz jego modyfikowanych w atmosferze gorącego wodoru form. Przedstawiono wpływ czasu redukcji na strukturę rozważanego szkła. Wyniki wskazują na silną tendencję do aglomeracji neutralnych atomów bizmutu w metaliczne nanostruktury.
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The effects of calcium–silicate–hydrate (C–S–H) seeds on reference microorganisms
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Photoluminescence of antimony-germanate-silicate glass doped with europium ions and silver nanoparticles
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Structural studies and melting of bismuth nanocrystals in reduced bismuthgermanate and bismuth silicate glasses.
PublikacjaOtrzymano nanostruktury krystalicznego bizmutu w matrycy XO2 (X=Si,Ge) oraz warstwę nanostruktur krystalicznego bizmutu na powierzchni redukowanych w atmosferze wodoru szkieł Bi0.33Ge0.67O1.84 i Bi0.57Si0.43O1.72. Kompozyt Bi-szkło badano metodą DSC, XRD oraz AFM. Zaobserwowano zmniejszenie temperatury topnienia nanokrystalicznego bizmutu znajdującego się w matrycy szkła z 544 K do 387 K oraz do 502 K w przypadku powierzchniowej...
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Structure and morphology of hydrogen reduced surface of bismuth germanateand bismuth silicate glasses.
PublikacjaOtrzymano nanostruktury krystalicznego bizmutu w matrycy XO2(X=Si,Ge) oraz warstwę nanostruktur krystalicznego bizmutu na powierzchni redukowanych w atmosferze wodoru szkieł Bi0.33Ge0.67O1. i Bi0.57Si0.43O1.72. Zaproponowano prosty model budowy zredukowanych szkieł bizmutowo-germanowych potwierdzony wynikami badań AFM i XRD. Obserwowane zmiany przewodnictwa elektrycznego redukowanych szkieł wyjaśniono na podstawie modelu.
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Helical core optical fibre made of Nd3+/Yb3+-doped oxyfluoride silicate glass
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Effect of temperature on luminescent properties of an antimony-silicate glass co-doped with Yb3+and Tm3+
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Ion conduction in beryllium-alumino-silicate glasses doped with sodium or sodium and lithium ions
PublikacjaElectrical properties of beryllium-alumino-silicate glasses containing sodium ions or sodium and lithium ions were studied with impedance spectroscopy technique over a frequency range from 10 mHz to 1 MHz and at temperature range from 213 to 473 K. The frequency- and temperature-dependent conductivity spectra of individual single alkali glasses were superimposed by means of the Summerfield scaling. Mixed-alkali glasses do not overlap...
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Barium boron aluminum silicate glass system for solid state optical gas sensors
PublikacjaRecent increasing demand for new eco-friendly materials and for low cost fabrication process for use in optical sensors field, raise concern about alternative materials for this application. We have designed two glass-ceramics compositions from the quaternary ROAl2O3- SiO2-B2O3(R=Ba) alkali-earth aluminum silicate system, labeled B72 and B69, with high refractive index (>1.6), large values of Abbe number (94.0 and 53.0, respectively),...
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Modifications of silicate bioglass synthesis and composition for in vitro dissolution control: Static and dynamic assessment
PublikacjaA set of fifteen calcium-phosphate-silicate glass samples, varying in alkali, magnesium, silicon, and nitrogen content, was prepared, and their structural, thermal, and in vitro dissolution properties were analyzed. Infrared spectroscopy showed a high degree of depolymerization of the silicate network consisting mainly of Q2 and Q3 units. Thermal analysis showed that the silicon content primarily affects both the glass transition...
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The bismuth atom neighbourhood in bismuth-silicate glasses from X-ray absorption experiment
PublikacjaPraca zawiera wyniki strukturalnej analizy EXAFS lokalnego otoczenia atomów bizmutu w krystalicznym tlenku bizmutu (odmiana alfa) i w szklach bizmutowo-krzemianowych o składzie xBi2O3 (1-x)SiO2,x=0.3, 0.4, 0.5, 0.6. Analizę XA- FS realizowano w oparciu o metodę GNXAS. Otrzymane wyniki porównano z danymi literaturowym.
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Moisture Influence on Compressive Strength of Calcium Silicate Masonry Units–Experimental Assessment and Normative Calculations
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Crystallization Mechanism and Optical Properties of Antimony-Germanate-Silicate Glass-Ceramic Doped with Europium Ions
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Structure and electric conductivity of reduced lead-germanate, bismuth-germanate and bismuth-silicate glasses modified with potassium
PublikacjaZbadano szkła germanianowo-ołowiowe i krzemianowo+bizmutowe. Warstwy metalicznych granul wytwarzano w nich poprzez redukcję powierzchni w atmosferze wodoru. Praca dotyczy wpływu potasu na właściwości szkła. Przeprowadzono badania metodami mikroskopii sił atomowych, DSC oraz pomiary przewodności elektrycznej. Stwierdzono, że obecność potasu poprawia mechaniczne i technologiczne właściwości szkła.
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Development of an Oxide Layer on Al 6061 Using Plasma Arc Electrolytic Oxidation in Silicate-Based Electrolyte
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Effect of Ag content on structural and luminescent properties of antimony-germanate-silicate glass doped with Eu3+ ions
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Investigation on broadband near-infrared emission in Yb3+/Ho3+ co-doped antimony–silicate glass and optical fiber
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Optical Characterization of Nano- and Microcrystals of EuPO4 Created by One-Step Synthesis of Antimony-Germanate-Silicate Glass Modified by P2O5
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Sustainable utilization of sodium silicate-based lead glass sludge as an alkali-activator for alkali-activated slag: Performance, characterization, and Pb-stabilization
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Linear and nonlinear impedance of iron containing silicate glasses
Dane BadawczeThe linear and nonlinear impedance ofglasses doped with iron oxide were measured. Glass samples (50 SiO2-50-xPbO-xFe2O3 in mol%) were prepared by the conventional melt quenching technique. The substrates were powdered in a mortar and melted in Al2O3 crucibles. The melting was conducted in air at 1623K. The melts were poured out on plate heated up to...
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Third-order nonlinear optical features of zirconia-added lead silicate glass ceramics embedded with Pb2Fe2O5 perovskite crystal phases and role of Fe ions
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The structure of lead-silicate glasses and nanocomposites doped with iron oxide
Dane BadawczeThe structure of iron-doped glasses and glass-ceramics were studied. Samples has the composition of 50SiO2–(50−x)PbO–xFe2O3, where x=15, 20 and 25 (in mol%). All samples were prepared by the conventional melt quenching technique; the melting was conducted in air at 1623 K in alumina crucibles. The melts were poured on a brass plate preheated to 573...
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The morphology of lead-silicate glasses containing nanocrystallites of iron oxides
Dane BadawczeThe topography of iron-doped glasses and glass-ceramics were studied. Samples has the composition of (50 − 0.5x)SiO2–(50 − 0.5x)PbO–xFe2O3, where x = 2, 5, 10, 15, 20 and 25 (in mol%). All sampleswere prepared by the conventional melt quenching technique; the melting was conducted in air at 1623 K in alumina crucibles. The melts were poured on a brass...
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The structure of lead-silicate glasses containing nanocrystallites of iron oxides
Dane BadawczeThe structure of iron-doped glasses and glass-ceramics were studied. Samples has the composition of (50 − 0.5x)SiO2–(50 − 0.5x)PbO–xFe2O3, where x = 2, 5, 10, 15, 20 and 25 (in mol%). All samples were prepared by the conventional melt quenching technique; the melting was conducted in air at 1623 K in alumina crucibles. The melts were poured on a brass...
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The morphology of lead-silicate glasses and nanocomposites doped with iron oxide
Dane BadawczeThe topography of iron-doped glasses and glass-ceramics were studied. Samples has the composition of 50SiO2–(50−x)PbO–xFe2O3, where x=15, 20 and 25 (in mol%). All sampleswere prepared by the conventional melt quenching technique; the melting was conducted in air at 1623 K in alumina crucibles. The melts were poured on a brass plate preheated to 573...
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Linear and nonlinear impedance of alkali and iron doped silicate-lead glasses
Dane BadawczeLinear and nonlinear impedance was studied for lead-silicate glass samples doped with iron ions and alkaline oxides. The compositions of glasses were as follows: (in %mol) 50% SiO2, 25% PbO, 15% Fe2O3 and 15% one of alkaline oxides: Na2O, K2O, Li2O. All samples were prepared by the conventional melt quenching technique. The substrates were powdered...
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Magnetic properties of of lead-silicate glasses and nanocomposites doped with iron oxide
Dane BadawczeMagnetic properties of iron-doped glasses and glass-ceramics were studied. Two different sets of glass samples were prepared. The first group of samples has the composition of (50 − 0.5x)SiO2–(50 − 0.5x)PbO– xFe2O3, where x = 15 and 20 (in mol%). Composition of the second group was 50SiO2–(50−x)PbO–xFe2O3, where x=15, 20 and 25 (in mol%). All sampleswere...
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Electrical properties of silicate-lead glasses containing nanostructures of iron oxides.
Dane BadawczeElectrical properties of silicate-lead glasses doped with different content of iron oxide was studied. The set of glass samples were prepared with the composition of (50 − 0.5x)SiO2–(50 − 0.5x)PbO–xFe2O3, where x = 2, 5, 10, 15, 20 and 25 (in mol%). All sampleswere prepared by the conventional melt quenching technique; the melting was conducted in...
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Electrical properties of nanostructures in lead-silicate glasses and nanocomposites doped with iron oxide
Dane BadawczeElectrical properties of iron oxide nanostructures observed in silicate glasses and glass-ceramics were studied. Two different sets of glass samples were prepared. The first group of samples has the composition of (50 − 0.5x)SiO2–(50 − 0.5x)PbO– xFe2O3, where x = 15, 20 and 25 (in mol%). Composition of the second group was 50SiO2–(50−x)PbO–xFe2O3, where...
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Grzegorz Boczkaj dr hab. inż.
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XRD-TiO2 and SiO2
Dane BadawczeData contain results from XRD measurements of amorphous silica and TiO2 of antase and rutile phases. The commercial TiO2 named as P25 produced by Evonik was also analyzed.
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Spectroscopic properties of Rhodamine B entrapped in hybrid porous nanolayers at high dye concentration
PublikacjaThe preparation procedure and characterization of Rhodamine B entrapped in zirconia, silica and mixed silica–zirconia nanolayers is described. The nanolayers were produced by the sol–gel spin-coating technique. The pronounced effect of the dye concentration on the absorption and fluorescence spectra as well as on time-resolved fluorescence spectra was found. The results show that the aggregation of Rhodamine B is stronger in silica...
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Asfalteny jako fazy stacjonarne w chromatografii cieczowej w normalnych układach faz
PublikacjaRozprawa doktorska dotyczy zbadania możliwości wykorzystania asfaltenów wydzielonych z: próżniowej pozostałości ropy naftowej, produktów jej utleniania i naturalnego asfaltu jako fazy stacjonarnej na powierzchni sorpcyjnej żelu krzemionkowego do rozdzielania nisko polarnych organicznych związków chemicznych w warunkach chromatografii cieczowej w normalnych układach faz, w odniesieniu do żelu krzemionkowego jako nośnika. Opracowano...