scholarly journals The dielectric relaxation behavior induced by sodium migration in the Na2CoSiO4 structure within a three-dimensional Co–O–Si framework

RSC Advances ◽  
2020 ◽  
Vol 10 (46) ◽  
pp. 27456-27473
Author(s):  
Kawthar Trabelsi ◽  
Karim Karoui ◽  
Abdelfattah Mahmoud ◽  
Jérôme Bodart ◽  
Frédéric Boschini ◽  
...  
Keyword(s):  
Solid State ◽  
Dielectric Relaxation ◽  
Three Dimensional ◽  
Orthorhombic Crystal System ◽  
Orthorhombic Crystal ◽  
Xrd Pattern ◽  
System P ◽  
Methods Of Synthesis ◽  
Dielectric Relaxation Behavior ◽  
Co Precipitation

A disodium cobalt(ii) orthosilicate material has been synthesized using improved solid-state and co-precipitation methods of synthesis. The Rietveld refinement of the XRD pattern of Na2CoSiO4 demonstrated an orthorhombic crystal system.

scholarly journals Normal and abnormal dielectric relaxation behavior in KTaO3 ceramics

RSC Advances ◽  
2017 ◽  
Vol 7 (80) ◽  
pp. 50680-50687 ◽  
Author(s):  
Lei Tong ◽  
Jie Sun ◽  
Shuting Wang ◽  
Youmin Guo ◽  
Qiuju Li ◽  
...  
Keyword(s):  
Solid State ◽  
Dielectric Relaxation ◽  
Solid State Reaction ◽  
Relaxation Behavior ◽  
Reaction Route ◽  
Conventional Solid State Reaction ◽  
Ceramic Samples ◽  
Solid State Reaction Route ◽  
Dielectric Relaxation Behavior

KTaO3 ceramic samples were prepared via a conventional solid state reaction route.

Dielectric relaxation behavior in co-precipitation derived ferrite (Zn1−xNix)Fe2O4 (0.2 ≤ x ≤ 0.5) ceramics

2016 ◽  
Vol 30 (02) ◽  
pp. 1550277 ◽  
Author(s):  
Y. P. Jiang ◽  
R. Li ◽  
X. G. Tang ◽  
Q. X. Liu ◽  
D. G. Chen
Keyword(s):  
Activation Energy ◽  
Electrical Properties ◽  
Dielectric Relaxation ◽  
Arrhenius Equation ◽  
Complex Impedance ◽  
Impedance Spectra ◽  
Nickel Doping ◽  
Dielectric Relaxation Behavior ◽  
Co Precipitation ◽  
Complex Impedance Spectra

The influence of nickel doping on the electrical properties and dielectric relaxation in Zn[Formula: see text]Ni[Formula: see text]Fe2O4 (ZNFO, [Formula: see text]) ceramics has been investigated via the dielectric and complex impedance spectra measurements. According to the modified Curie–Weiss law, the diffusivity factor of the ZNFO ceramics from 1.69 to 2.02 with [Formula: see text] increasing from 0.2 to 0.5, respectively. Two relaxation peaks are observed in the nickel doped samples, by employing the modified Arrhenius equation, two activation energy values of different sintering temperatures were calculated and analyzed in combination with oxygen vacancy. The Cole–Cole plots showed that the semicircular arcs which are nonideal Debye type, and the grain boundaries resistance increases with increasing Ni concentration.

Comparison between Solid State Reaction and Coprecipitation Method of Titanium Oxide Addition on the YBa2Cu3Oδ Ceramics

2020 ◽  
Vol 1010 ◽  
pp. 187-193
Author(s):  
Ali Arlina ◽  
Nadiah Ameram ◽  
Nik Alnur Auli
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Single Phase ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Orthorhombic Crystal ◽  
Sem Images ◽  
Orthorhombic Crystal Structure ◽  
Oxide Addition ◽  
Co Precipitation

In this work, comparison of TiO2 additions on the physical properties of YBa2Cu3Oδ superconductor system with nominal starting compositions at x= 0, 1, 2, and 5 wt.% was studied derived via solid state reaction and co-precipitation method. The samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The result from XRD shown that all the samples were polycrystalline for solid state reaction, while single phase appear for co-precipitation methods. The intensity of the peak become higher with increasing amount of TiO2 addition indicating the presence of increased amount of the unreacted in the samples. The refine lattice parameters indicated that all the samples have an orthorhombic crystal structure without occurrence of orthorhombic-tetragonal phase transformation. Furthermore, from SEM images for solid state reaction and co-precipitation method showed that the grain size of the samples decreased with TiO2 increased. Small addition of TiO2 derived from co-precipitation method enhanced the YBCO microstructures.

scholarly journals Comparative Study on AC Susceptibility of YBa2Cu3O7−δ Added with BaZrO3 Nanoparticles Prepared via Solid-State and Co-Precipitation Method

Crystals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 655 ◽  
Author(s):  
Nurhidayah Mohd Hapipi ◽  
Jee Lim ◽  
Soo Chen ◽  
Oon Lee ◽  
Abdul Shaari ◽  
...  
Keyword(s):  
Grain Size ◽  
Solid State ◽  
Grain Boundaries ◽  
Ac Susceptibility ◽  
Precipitation Method ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Weight Percentage ◽  
Average Grain Size ◽  
Co Precipitation

Polycrystalline samples of YBa2Cu3O7−δ (Y-123) added with x mol% of BaZrO3 (BZO) nanoparticles (x = 0.0, 2.0, 5.0, and 7.0) were synthesized using co-precipitation (COP) and solid-state (SS) method. X-ray diffraction (XRD) patterns showed the formation of Y-123 and Y-211 as the major and minor phases, respectively. The samples prepared using COP method showed higher weight percentage of Y-123 phase (≤98%) compared to the SS samples (≤93%). A peak corresponding to BZO was also found in the samples added with BZO nanoparticles. The increasing intensity of the BZO peak as the BZO amount increased showed the increasing amount of the unreacted nanoparticles in the samples. Refinement of unit cell lattice parameters indicated that all the samples have an orthorhombic crystal structure and there is no orthorhombic-tetragonal phase transformation. As observed using scanning electron microscopy (SEM), all the samples showed randomly distributed grains with irregular shape. The average grain size for the pure sample prepared using COP method is smaller (0.30 µm) compared with that of the pure SS sample (1.24 µm). Addition of 7.0 mol% BZO led to an increase of average grain size to 0.50 μm and 2.71 μm for the COP and SS samples, respectively, indicating grain growth. AC susceptibility (ACS) measurement showed a decrease in the onset critical temperature, Tc-onset with BZO addition. Comparatively, Tc-onset for the COP samples is higher than that of the SS samples. The value of Josephson’s current, Io increased up to 2.0 mol% BZO addition, above which the Io decreased more drastically for the SS samples. The value of Io is 53.95 μA and 32.08 μA for the 2.0 mol% BZO added SS and COP samples, respectively. The decrease of Io is attributed to the distribution of BZO particles at the grain boundaries as also reflected in the drastic decrease of phase lock-in temperature, Tcj. As a result of smaller average grain size, the presence of more grain boundaries containing insulating BZO particles led to lower Io in the COP samples.

A Free Energy Perturbation Approach to Estimate the Intrinsic Solubilities of Drug-like Small Molecules

2019 ◽  
Author(s):  
Sayan Mondal ◽  
Gary Tresadern ◽  
Jeremy Greenwood ◽  
Byungchan Kim ◽  
Joe Kaus ◽  
...  
Keyword(s):  
Solid State ◽  
Small Molecules ◽  
Three Dimensional ◽  
Aqueous Solubility ◽  
Computational Approach ◽  
Free Energy Perturbation ◽  
Perturbation Approach ◽  
Energy Perturbation ◽  
State Form ◽  
Good Agreement

<p>Optimizing the solubility of small molecules is important in a wide variety of contexts, including in drug discovery where the optimization of aqueous solubility is often crucial to achieve oral bioavailability. In such a context, solubility optimization cannot be successfully pursued by indiscriminate increases in polarity, which would likely reduce permeability and potency. Moreover, increasing polarity may not even improve solubility itself in many cases, if it stabilizes the solid-state form. Here we present a novel physics-based approach to predict the solubility of small molecules, that takes into account three-dimensional solid-state characteristics in addition to polarity. The calculated solubilities are in good agreement with experimental solubilities taken both from the literature as well as from several active pharmaceutical discovery projects. This computational approach enables strategies to optimize solubility by disrupting the three-dimensional solid-state packing of novel chemical matter, illustrated here for an active medicinal chemistry campaign.</p>

scholarly journals Phase Transition and Coefficients of Thermal Expansion in Al2−xInxW3O12 (0.2 ≤ x ≤ 1)

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4021
Author(s):  
Andrés Esteban Cerón Cerón Cortés ◽  
Anja Dosen ◽  
Victoria L. Blair ◽  
Michel B. Johnson ◽  
Mary Anne White ◽  
...  
Keyword(s):  
Phase Transition ◽  
Thermal Expansion ◽  
Thermal Shock ◽  
Monoclinic Phase ◽  
Ceramic Materials ◽  
Precipitation Method ◽  
Scanning Calorimetry ◽  
Orthorhombic Crystal ◽  
Co Precipitation

Materials from theA2M3O12 family are known for their extensive chemical versatility while preserving the polyhedral-corner-shared orthorhombic crystal system, as well as for their consequent unusual thermal expansion, varying from negative and near-zero to slightly positive. The rarest are near-zero thermal expansion materials, which are of paramount importance in thermal shock resistance applications. Ceramic materials with chemistry Al2−xInxW3O12 (x = 0.2–1.0) were synthesized using a modified reverse-strike co-precipitation method and prepared into solid specimens using traditional ceramic sintering. The resulting materials were characterized by X-ray powder diffraction (ambient and in situ high temperatures), differential scanning calorimetry and dilatometry to delineate thermal expansion, phase transitions and crystal structures. It was found that the x = 0.2 composition had the lowest thermal expansion, 1.88 × 10−6 K−1, which was still higher than the end member Al2W3O12 for the chemical series. Furthermore, the AlInW3O12 was monoclinic phase at room temperature and transformed to the orthorhombic form at ca. 200 °C, in contrast with previous reports. Interestingly, the x = 0.2, x = 0.4 and x = 0.7 materials did not exhibit the expected orthorhombic-to-monoclinic phase transition as observed for the other compositions, and hence did not follow the expected Vegard-like relationship associated with the electronegativity rule. Overall, compositions within the Al2−xInxW3O12 family should not be considered candidates for high thermal shock applications that would require near-zero thermal expansion properties.

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