X-RAY STUDY OF CUBIC PHASES IN TERNARY SYSTEMS OF SURFACTANT DDAB, WATER AND OIL

1990 ◽  
Vol 51 (C7) ◽  
pp. C7-25-C7-34 ◽  
Author(s):  
P. BAROIS ◽  
D. EIDAM ◽  
S. T. HYDE
Keyword(s):  
X Ray ◽  
Proceedings ◽  
2020 ◽  
Vol 62 (1) ◽  
pp. 4
Author(s):  
Hadj Bellagra ◽  
Oksana Nyhmatullina ◽  
Yuri Kogut ◽  
Halyna Myronchuk ◽  
Lyudmyla Piskach

Quaternary semiconductor materials of the Pb4Ga4GeS(Se)12 composition have attracted the attention of researchers due to their possible use as active elements of optoelectronics and nonlinear optics. The Pb4Ga4GeS(Se)12 phases belong to the solid solution ranges of the Pb3Ga2GeS(Se)8 compounds which form in the quasi-ternary systems PbS(Se)−Ga2S(Se)3−GeS(Se)2 at the cross of the PbGa2S(Se)4−Pb2GeS(Se)4 and PbS(Se)−PbGa2GeS(Se)6 sections. The quaternary sulfide melts congruently at 943 K. The crystallization of the Pb4Ga4GeSe12 phase is associated with the ternary peritectic process Lp + PbSe ↔ PbGa2S4 + Pb3Ga2GeSe8 at 868 K. For the single crystal studies, Pb4Ga4GeS(Se)12 were pre-synthesized by co-melting high-purity elements. The X-ray diffraction results confirm that these compounds possess non-centrosymmetric crystal structure (tetragonal symmetry, space group P–421c). The crystals were grown by the vertical Bridgman method in a two-zone furnace. The starting composition was stoichiometric for Pb4Ga4GeS12, and the solution-melt method was used for the selenide Pb4Ga4GeSe12. The obtained value of the bandgap energy for the Pb4Ga4GeS12 and Pb4Ga4GeSe12 crystals is 1.86 and 2.28 eV, respectively. Experimental measurements of the spectral distribution of photoconductivity for the Pb4Ga4GeS12 and Pb4Ga4GeSe12 crystals exhibit the presence of two spectral maxima. The first lies in the region of 570 (2.17 eV) and 680 nm (1.82 eV), respectively, and matches the optical bandgap estimates well. The locations of the admixture maxima at about 1030 (1.20 eV) and 1340 nm (0.92 eV), respectively, agree satisfactorily with the calculated energy positions of the defects vs. and VSe.


Author(s):  
M.A Siddig ◽  
S Radiman ◽  
S.V Muniandy ◽  
L.S Jan
Keyword(s):  

2015 ◽  
Vol 245 ◽  
pp. 200-203 ◽  
Author(s):  
Maxim Alexandrovich Pugachevskii ◽  
Viktor Igorevich Panfilov

The conditions of formation of the ZrO2 and HfO2 high-temperature (tetragonal and cubic) phases in the ablated nanoparticles were investigated. X-ray diffraction and transmission electron microscopy data demonstrate that laser intensities above 109 W/m2 ensure the formation of the ZrO2 high-temperature phases, while intensities above 5·109 W/m2 do the formation of the HfO2 high-temperature phases. Quantitative content of the high-temperature phases in layers of the ablated nanoparticles increases with raising the intensity. The obtained nanoparticles exhibit good thermal stability.


2000 ◽  
Vol 39 (5-6) ◽  
pp. 251-255 ◽  
Author(s):  
N. F. Chaban ◽  
S. I. Mikhalenko ◽  
Yu. B. Kuz’ma

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Rashmi Gupta ◽  
Seema Verma ◽  
Vishal Singh ◽  
K. K. Bamzai

A ternary system of lead niobate–lead zirconate–lead titanate with composition xPN–yPZ–(x-y)PT where x=0.5 and y=0.15, 0.25, and 0.35 known as PNZT has been prepared by conventional mixed oxide route at a temperature of 1100°C. The formation of the perovskite phase was established by X-ray diffraction analysis. The surface morphology studied by scanning electron microscopy shows the formation of fairly dense grains and elemental composition was confirmed by energy dispersive X-ray analysis. Dielectric properties like dielectric constant and dielectric loss (ε′ and tan⁡δ) indicate poly-dispersive nature of the material. The temperature dependent dielectric constant (ε′) curve indicates relaxor behaviour with two dielectric anomalies. The poly-dispersive nature of the material was analysed by Cole-Cole plots. The activation energy follows the Arrhenius law and is found to decrease with increasing frequency for each composition. The frequency dependence of ac conductivity follows the universal power law. The ac conductivity analysis suggests that hopping of charge carriers among the localized sites is responsible for electrical conduction. The ferroelectric studies reveal that these ternary systems are soft ferroelectric.


2021 ◽  
Vol 43 (3) ◽  
pp. 314-314
Author(s):  
Ahmet Hamdi BAKIR and Handan ZL TORUN Ahmet Hamdi BAKIR and Handan ZL TORUN

The most important part of a solid oxide fuel cell is the ceramic electrolyte. In this study, cerium oxide (CeO2) was used as the ceramic electrolyte, and different dopant types were used to increase total conductivity. In this study, the most commonly used Sm, and the less frequently used Ho elements were doped simultaneously. As a result, the effect of dope and different synthesis methods on electrolyte properties was evaluated. Three rates were studied with the total amount of Sm-Ho being 20%. The effect of the dopant types on conductivity with critical radius effect was investigated. These dope types were placed in a CeO2 crystal lattice by using the sol-gel and hydrothermal methods. After synthesis, the stable phase was obtained at room temperature. X-ray powder diffraction (XRD) was used for phase determination. The thermogravimetry (TG) determined mass change. Scanning electron microscopy (SEM) was used in the analysis of surface morphology. Total conductivity measurements were measured by the four-probe dc method. After synthesis processes, cubic compounds were obtained. The total conductivity values of the cubic phases samples obtained by two different synthesis methods were compared. The highest conductivity was observed in the sol-gel compounds. The highest electrical conductivity Ce0.80Sm0.10Ho0.10O2 system sol- gel; 6.92x10-3(Ωcm)1- at 655 oC. It was found that the compound obtained as a result of the evaluations could be used ceramic electrolyte application.


2019 ◽  
Vol 12 (1) ◽  
pp. 40 ◽  
Author(s):  
Justyna Knapik-Kowalczuk ◽  
Krzysztof Chmiel ◽  
Karolina Jurkiewicz ◽  
Natália Correia ◽  
Wiesław Sawicki ◽  
...  

The purpose of this paper is to examine the physical stability as well as viscoelastic properties of the binary amorphous ezetimibe–simvastatin system. According to our knowledge, this is the first time that such an amorphous composition is prepared and investigated. The tendency toward re-crystallization of the amorphous ezetimibe–simvastatin system, at both standard storage and elevated temperature conditions, have been studied by means of X-ray diffraction (XRD). Our investigations have revealed that simvastatin remarkably improves the physical stability of ezetimibe, despite the fact that it works as a plasticizer. Pure amorphous ezetimibe, when stored at room temperature, begins to re-crystallize after 14 days after amorphization. On the other hand, the ezetimibe-simvastatin binary mixture (at the same storage conditions) is physically stable for at least 1 year. However, the devitrification of the binary amorphous composition was observed at elevated temperature conditions (T = 373 K). Therefore, we used a third compound to hinder the re-crystallization. Finally, both the physical stability as well as viscoelastic properties of the ternary systems containing different concentrations of the latter component have been thoroughly investigated.


Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2396 ◽  
Author(s):  
Jinfa Liao ◽  
Hang Wang ◽  
Tzu-Yu Chen

The phase equilibrium of the Ni–Al–La ternary system in a nickel-rich region was observed at 800 °C and 1000 °C using scanning electron microscopy backscattered electron imaging, energy dispersive X-ray spectrometry and X-ray diffractometry. The solubility of Al in the Ni5La phase was remeasured at 800 °C and 1000 °C. Herein, we report a new ternary phase, termed Ni2AlLa, confirmed at 800 °C. Its X-ray diffraction (XRD) pattern was indexed and space group determined using Total Pattern Solution (TOPAS), and the suitable lattice parameters were fitted using the Pawley method and selected-area electron diffraction. Ni2AlLa crystallizes in the trigonal system with a space group R3 (no. 146), a = 4.1985 Å and c = 13.6626 Å. A self-consistent set of thermodynamic parameters for the Al–La and Ni–La binary systems and the Ni–Al–La ternary system includes a Ni2AlLa ternary phase, which was optimized using the CALPHAD method. The calculated thermodynamic and phase-equilibria data for the binary and ternary systems are consistent with the literature and measured data.


2019 ◽  
Vol 5 (5) ◽  
pp. eaaw2399 ◽  
Author(s):  
Fang Lu ◽  
Thi Vo ◽  
Yugang Zhang ◽  
Alex Frenkel ◽  
Kevin G. Yager ◽  
...  

Space-filling generally governs hard particle packing and the resulting phases and interparticle orientations. Contrastingly, hard-shaped nanoparticles with grafted soft-ligands pack differently since the energetically interacting soft-shell is amenable to nanoscale sculpturing. While the interplay between the shape and soft-shell can lead to unforeseen packing effects, little is known about the underlying physics. Here, using electron microscopy and small-angle x-ray scattering, we demonstrate that nanoscale cubes with soft, grafted DNA shells exhibit remarkable packing, distinguished by orientational symmetry breaking of cubes relative to the unit cell vectors. This zigzag arrangement occurs in flat body-centered tetragonal and body-centered cubic phases. We ascribe this unique arrangement to the interplay between shape and a spatially anisotropic shell resulting from preferential grafting of ligands to regions of high curvature. These observations reveal the decisive role played by shell-modulated anisotropy in nanoscale packing and suggest a plethora of new spatial organizations for molecularly decorated shaped nanoparticles.


1994 ◽  
Vol 4 (2) ◽  
pp. 275-286 ◽  
Author(s):  
M. Clerc ◽  
E. Dubois-Violette

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