Wyniki wyszukiwania - BazTech

1

Effect of Calcination Temperature on the Stability of the Perovskite Materials – Study of Structural and Morphological Properties

Maou Amina, Gouitaa Najwa, Lamcharfi Taj Dine, Kandri Noureddine Idrissi

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 8

1--8

EN

In this research, the solid-state method was utilized to synthesize LaFeO3 powders, with La2O3 and Fe2O3 being employed as precursor materials. The prepared samples were calcined at different temperatures 800°C, 900°C, 1000°C, 1100°C, 1200°C and 1300°C for 4h to study phase stability. The thermal effect on structural and morphological properties was reported. The X-ray diffraction results confirmed the pure phase in its orthorhombic configuration at 1200°C and 1300°C, which was confirmed by Rietveld’s analysis. Scanning electron microscopy coupled with Energy-dispersive X-ray spectroscopy was employed to analyze the surface morphology and compositional characteristics. In addition, the samples were analyzed by Fourier Transform Infrared Spectroscopy. The thermal behavior of the product was investigated through the utilization of thermogravimetric analysis.

2

Tin oxide-titania based electronic system: synthesis, structural, microstructural and dielectric properties

Sahoo Limali, Bhuyan S., Das S.N.

Composites Theory and Practice

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2023

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R. 23, nr 4

183--190

EN

SnO2-TiO2, a composite ceramic electronic element was produced by employing a cost-effective and reliable method known as the solid-state synthesis process. The phase, microstructure, chemical composition, and electrical characteristics across a wide frequency range of 1 kHz-1 MHz were evaluated in detail to comprehend this electronic candidate as a capacitive component. The XRD study revealed a polycrystalline tetragonal structure with a crystallite size of 57.9 nm. The SEM micrograph revealed uniformly distributed grains and the calculated average grain size is 0.199 μm. A hydrophilic porous nature was also ascertained from the SEM micrograph. A high dielectric constant (2623) with low dielectric loss (7.5) resulted at the 1 kHz frequency and 400°C. The enhanced capacitive nature was determined by impedance spectroscopy under an extensive frequency and temperature range. The mechanism and nature of conduction at various temperatures were ascertained from the conductivity analysis. The electric modulus characteristics substantiate the non-Debye relaxation of this composite. Based on the comprehensive results, the synthesized component can have prospective applications as a capacitive component for humidity sensors and other electronic devices.

3

Side-pumped neodymium laser with self-adaptive, nonreciprocal cavity

Kaskow M., Galecki L., Zendzian W., Gorajek L., Jabczynski J. K.

Opto-Electronics Review

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2016

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Vol. 24, No. 1

10--14

EN

We demonstrate the generation of a near-diffraction-limited beam in a diode-side-pumped Nd:YAG slab laser with a nonreciprocal, self-adaptive cavity. The energy output of 228 mJ with 17.2% slope efficiency and 17.3% optical-to-optical efficiency was obtained.

4

Synthesis and characterization of YAG:Ce phosphors for white LEDs

Tucureanu V., Matei A., Avram A. M.

Opto-Electronics Review

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2015

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Vol. 23, No. 4

239-251

EN

Worldwide commercial interest in the production of cerium doped yttrium aluminium garnet (YAG:Ce) phosphors is reflected in the widespread use of white light emitting devices. Despite of the fact that YAG:Ce is considered a “cool phosphor” it is the most important in white LED technology. This article reviews the developed techniques for producing phosphors with superior photoluminescence efficiency, including solid-state reaction, sol-gel and (co)precipitation methods. Also, by co-doping with rare earth elements, a red/blue shift is reached in the spectrum. The characteristics of YAG:Ce phosphors are investigated because the properties of the phosphors are strongly influenced by the synthesis routes and the sintering temperature treatment. After the phase analysis, morphology and emission studies of the phosphors there may be seen the conditions when the transition from the amorphous phase to the crystalline phase appears, when luminescent properties are influenced by the crystalline form, purity, average size of the particles, co-doping and so on.

5

Structure and lithium transport phenomena in a new tripodand-grafted polysiloxane

Walkowiak M., Waszak D., Osińska-Broniarz M., Gierczyk B.

Polimery

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2011

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T. 56, nr 4

294-301

EN

New polymeric host for Li+ cation-conducting polymer electrolytes has been described. Poly(methyl(2-tris(2-(2-methoxyethoxy)ethoxy)silyl)ethyl)siloxane) trimethylsilyl terminated, average molecuar weight 19 100, has been synthesized by catalytic hydrosilylation reaction between a polysiloxane and appropriate vinyl-functionalized tripodand-type silane. On the basis of the obtained macromolecule a flexible polymer electrolyte membrane has been prepared by dissolving appropriate amount of lithium salt (LiPF6) in the polymer matrix. Relation between the molecular structure and lithium cation conduction mechanism has been studied and discussed in terms of temperature dependence of specific conductivity and lithium cation transport number. The issue of decoupling of cationic mobility from polymer segmental motions has been addressed and discussed on the basis of solid state 7Li NMR measurements.

PL

Zbadano właściwości zsyntetyzowanego nowego typu polimerowego elektrolitu z mechanizmem przewodzenia opartym na kationach litu. Na drodze katalitycznej hydrosililacji, przy użyciu polisiloksanu i trójpodandu krzemowego z grupą winylową otrzymano poli(2-tris(2-(2-metoksyetoksy)etyloksy)sililoetylo)metylosiloksan o średnim ciężarze cząsteczkowym 19 100. W wyniku rozpuszczenia w wytworzonej matrycy polimerowej soli litu (LiPF6) uzyskano elastyczne membrany elektrolitowe. Określano zależność właściwości elektrochemicznych oraz mechanizmu przewodnictwa jonowego od struktury kompleksu polimer-sól litu. Na podstawie pomiarów 7Li NMR rozważono problem braku sprzężenia dynamiki łańcucha polimerowego i dynamiki kationu litu. Struktura molekularna zsyntezowanego związku zawiera centra trójpodandowe przyłączone do polisiloksanowego łańcucha głównego (rys. 1). Polimer wykazuje strukturę amorficzną ze słabo zaznaczoną przemianą szklistą w temperaturze z zakresu 10-20 °C (rys. 2, 3). Zależność logarytmu przewodnictwa od odwrotności temperatury, wyznaczona dla kompleksu polimer-sól litu, ma przebieg prostoliniowy, co sugeruje nietypowy dla polieterowych elektrolitów polimerowych mechanizm przewodnictwa, oraz brak sprzężenia pomiędzy ruchami termicznymi segmentów polimerowych a transportem jonowym (rys. 4). Liczba przenoszenia kationu litu jest stosunkowo duża, co wskazuje na znaczną ruchliwość kationu Li+ (rys. 5). W celu dokładniejszej oceny dynamiki kationu wykonano 7Li NMR uzyskanego kompleksu w szerokim zakresie temperatury i określono zależność szerokości piku od temperatury (rys. 6). Zależność ta nie wykazuje charakterystycznego przegięcia w temperaturze przemiany szklistej, co potwierdza przypuszczenie o braku sprzężenia dynamiki polimeru z dynamiką kationu. Ponadto zaobserwowano rozszczepienie piku NMR poniżej temperatury ok. -30 °C, co przypisano dwóm odmiennym koordynacjom kationu przez eterowe atomy tlenu. Badania pozwoliły na zaproponowanie nowego typu mechanizmu transportu litu w polimerze, charakterystycznego dla obecności zorganizowanych centrów podandowych (rys. 7, schemat A). Otrzymany polimer jest interesującym przykładem przewodzącej matrycy dla kationów i może stanowić podstawę do wytwarzania wysokoprzewodzących elektrolitów polimerowych do akumulatorów litowych.