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Eu:Y2O3nanophosphors (NPs) with different Eu concentrations (3, 5, and 7 at%) were successfully synthesized via the sol–gel method. All synthesized powders had a cubic bixbyite‐type crystal structure with space group Ia‐3. It was observed they had agglomerated sphere‐like morphologies. In addition, a neck formation between the particles, which was the result of the sintering effect at the increasing calcination temperature, was also observed by scanning electron microscopy analysis. Raman and X‐ray photoelectron spectroscopy (XPS) analyses confirmed that the Eu dopant entered into the Y2O3host. The XPS peak positions shifted to relatively higher binding energy values with increasing dopant concentration and calcination temperature. Increasing Eu dopant concentration in the host structure also increased the 3+ valence ions. The band gap values of the NPs varied between 4.30 and 4.54 eV. The powders doped with 5 at% Eu was active as photocatalysts and the powders that were synthesized at 800°C exhibited highly photocatalytic activity. Eu doped Y2O3nanoparticles prepared by the sol–gel method were examined photocatalytic behavior. 5 at% Eu doped samples were photocatalytically more active materials compared to the others. Moreover, the photocatalytic activity of particles belonging 5 at% Eu doped samples synthesized at lower temperature was almost two times higher than those which had a similar dopant rate synthesized at higher temperatures. Those with the highest optical band gap exhibited the highest photocatalytic activity was observed.

Terbium oxide (Tb2O3) phosphors were prepared the using sol‐precipitation method with the use of different precursor concentrations. The X‐ray diffraction (XRD) patterns showed C‐type body‐centered cubic phase, space group Ia‐3, and the crystallite size values were found in the range of 19.45–32.34 nm depending on the solution composition and calcination temperature. As the crystallinity increased, the defects in the structure decreased, that is, the dislocation density decreased. Under the excitation at 325 nm, although all the Tb2O3phosphors emitted a single peak around 544 nm (5D4‐7F5transition) in PL spectra, when the peak was enlarged, the presence of additional peaks shifted to the red/blue region was also observed. The color chromaticity coordinates showed that it exhibited different tones of emission from light yellow to green depending on the precursor concentration and calcination temperature. With increasing the precursor concentration, nucleation rate increased and the particle shape changed from nearly spherical to rod‐like. They may be promising for laser devices and display applications due to their strong green emission. Tb2O3phosphors were prepared by sol‐precipitation method using different precursor concentrations and shift in the PL emission with change of the precursor concentration was determined with CIEXYZ color space coordinates, and the effect of the change in morphology on the PL behavior was investigated. The precursor concentration, crystallite size, morphology, lattice defects were found to have direct effects on the PL behavior.

Cobalt is used in applications that require high densities and good mechanical properties. Cobalt powder is used in batteries, cemented carbides, stainless steel, machine tools and also in manufacturing of metal matrix diamond tools designed for the cutting and drilling of hard rocks and concrete. This study aimed to investigate the structural properties and compare the mechanical and micro structural properties of two different cobalt powders, specifically the spherical grain (Co-S) and rod-like grain shapes (Co-R), to enhance the cutting performances of the diamond cutting tools. The flow properties of the powders, as a function of the shear strain rate, were determined using Freeman Technology (FT4) rheometer analysis. The microstructural characterizations were conducted using scanning electron microscopy (SEM)-energy-dispersive spectroscopy (EDS) and X-ray diffraction (XRD) analyses, and the crystallite size values were calculated using the Williamson-Hall method. The mechanical characterizations were conducted using the density measurement, hardness, compression test, and wear test. Based on the results of the FT4 rheometer analysis, the Co-S powder had higher compressibility and air permeability compared to the Co-R powder. The SEM analysis of the sintered samples revealed multiple pores in the Co-R powder. The highest mechanical properties were obtained in the sintered sample of the S series. The most suitable Co powder for the preparation of metal matrix mixtures of diamond cutting tools produced using SPS was determined to be the Co-S series.

In this study, doped ytterbium oxide (Yb2O3) nanoparticles (NPs) with different dopant type (Eu and / or Tb) and undoped were synthesized by wet chemical method using nitrate salt as a starting source. Afterwards, they were calcined at 900 °C for 4 h. The crystal structure phase, size, and morphology of undoped and doped Yb2O3 nanoparticles (NPs) were characterized by X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). Undoped and doped NPs were exhibited cubic bixbyite-type crystal structure (Ia-3 space group). Lattice parameter changes caused by dopant element in NPs were examined using X-ray peak profile analysis. In order to investigate the occuring changes in the crystal structure, average crystallite size (CS) and lattice parameter (LP) values were computed with Williamson–Hall (W–H) and Cohen-Wagner (C–W) methods, respectively. It was observed that the crystal structure of the doped NPs expanded compared to the undoped Yb2O3 NPs, which explains the increase in the LP and CS values. The LP values of all the NPs were ranged from 10.444 Å (R2 = 94.9) to 10.453 Å (R2 = 81.8) while the CS of them were between 19 nm (R2 = 95.9) and 24 nm (R2 = 88.8). All the NPs exhibited nearly spherical and agglomerate structure and there were also few pores between the agglomerate particles in the structure. Besides, continuous agglomerate morphology formation was observed in particles containing Tb. The average nanoparticle size values were varied between 46 and 115 nm depending on the dopant element.

Magnetic‐luminescent composite nanoparticles (Fe3O4@ZnO:RE) with a core/shell structure are produced by a simple process. Magnetite nanoparticles (Fe3O4) are coated with rare‐earth‐doped zinc oxide (ZnO). Core/shell structure is confirmed by high‐resolution transmission electron microscopy (HR‐TEM) analysis. X‐ray diffraction analysis results show that cubic magnetite Fe3O4and hexagonal ZnO phases originate from the core and the shell, respectively. Hexagonal ZnO and cubic magnetite Fe3O4phases belonging all nanoparticles are confirmed by HR‐TEM benefiting the lattice fringe. All the nanoparticles present superparamagnetic behavior. Under 532 nm excitation, they release the emission in the visible and infrared regions. They exhibit blue–green emission attributed to 2H11/2–4I15/2, 4S3/2–4I15/2transitions, red emission attributed to 4F9/2–4I15/2transitions, and infrared emission ascribed to 4F9/2–4I15/2, 2F7/2–2F5/2transitions. Above the 0.2mol% dopant ratio, the luminescence intensity starts to decrease because of the concentration quenching. The produced nanoparticles are promising for bioimaging and magnetic hyperthermia treatment, due to their magnetic and luminescent properties, orientation to the target area, and their presence in the target area can be determined. Herein, multifunctional magnetic‐luminescent nanoparticles are fabricated for bioimaging and magnetic hyperthermia treatment. High‐resolution transmission electron microscopy images confirm the core/shell structure. In addition to exhibiting superparamagnetic behavior, they exhibit the emission. While the magnetic feature provides the possibility of directing the nanoparticles to the target region, the luminescence feature allows the verification of their presence in the target region.

This study aimed to investigate the interest and perceptions of children aged between 4 and 8 towards the museum and the objects in the museum through their own experiences in the natural environment. The design of the study was of qualitative research design. The study group was composed of participating 12 children from among those who were visiting the museum with their family, relations or school group. The observation of these children during their visit in Antalya museum as the natural environment focused on what they engaged in, what they directed their attention to, what kind of process they underwent and their general interest. The data obtained through these observations were interpreted using content analysis. According to the findings obtained the monuments to which children directed the highest attention was statues, remains of sarcophaguses and tombs. It was observed that children asked such questions about the monuments as what the monument is, what it was made of, who used it, how and where it was excavated; that they produced such responses as laughter, fear and appreciation toward the monuments in the museum; and that they made comments related to the fashion in which the monuments were exhibited in the museum.