Microstructure and Electrochemical Behaviour of some SnO2-based Inert Electrodes in Aluminium Electrolysis

2002 ◽  
Vol 57 (9-10) ◽  
pp. 71-75 ◽  
Author(s):  
Ana-Maria Popescu ◽  
Suzana Mihaiu ◽  
Stefania Zuca
Keyword(s):  
Activation Energy ◽  
Solid Solution ◽  
Structural Analysis ◽  
Electrochemical Behaviour ◽  
X Ray Diffraction ◽  
X Ray ◽  
Seebeck Coefficients ◽  
Aluminium Production ◽  
Anodic Polarisation ◽  
Carbon Anodes

Some types of anodes that could replace the usual carbon anodes in aluminium production by the Hall-Heroult process are based on SnO2. The present investigation deals with SnO2-Sb2O3-CuO ceramics having an SnO2 content of ≥96%), Sb2O3 and CuO being dopants. The ceramic pellets, thermally treated at 1400 °C for 4 hours, were analysed by X-ray diffraction and IR spectroscopy. The structural analysis of the samples evidenced an SnO2 (ss) type solid solution. All samples were electronically conductive (small negative values of the Seebeck coefficients), having an activation energy ranging within 0.02 - 0.3 eV.The anodic polarisation curves obtained with those anodes in an electrolyte of 88% Na3AlF6, 7% Al2O3 and 5% CaF2 were studied. The results were correlated with the microstructure of the investigated samples.

Microstructure and Electrochemical Behaviour of some SnO2-based Inert Electrodes in Aluminium Electrolysis

2002 ◽  
Vol 57 (1-2) ◽  
pp. 71-75 ◽  
Author(s):  
Ana-Maria Popescu ◽  
Suzana Mihaiu ◽  
Stefania Zuca
Keyword(s):  
Solid Solution ◽  
Structural Analysis ◽  
Ir Spectroscopy ◽  
Electrochemical Behaviour ◽  
X Ray Diffraction ◽  
X Ray ◽  
Seebeck Coefficients ◽  
Aluminium Production ◽  
Anodic Polarisation ◽  
Carbon Anodes

Some types of anodes thai could replace die usual carbon anodes in aluminium production by die Hall-Keroult process are based on SnO2. The presenr Investigation deals nidi SnO2-Sb2O3-CuO ceramics having an SnO2. conrent of ≥ 96%), Sb2O3, and CuO being dopants The ceramic pellets, thermally treated at 1400 °C for 4 hours, were analysed by X-ray diffraction and IR. spectroscopy. The structural analysis of the samples evidenced an SnO2(88) type solid solution. All samples were electronically conductive (small negative values of the Seebeck coefficients), having an sanation energy ranging within 0.02 - 0.3 eV.The anodic polarisation curves obtained with those anodes in an electrolyte of 88 % Na3AlF6, 7% Al2O3, and 5% CaF2 were studied- The results were correlated with the microstrucrure of die invesagated samples.

Thermal Stability vs. Crystallization of the Lithiumsilicate Glasses with Addition Zirconium Dioxide and Titanium Dioxide

2008 ◽  
Vol 39-40 ◽  
pp. 399-401
Author(s):  
Viliam Pavlík ◽  
Eugen Jóna ◽  
Martina Sapietová ◽  
Soňa Šnircová
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Thermal Analysis ◽  
Titanium Dioxide ◽  
Differential Thermal Analysis ◽  
Structural Analysis ◽  
Zirconium Dioxide ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Relationship

The glasses with composition of Li2O . 2 SiO2 . n ZrO2 . n TiO2 (where n = 0; 0.015; 0.031; 0.050; 0.075; 0.1; 0.15; 0.2) were prepared and the relationship between structural and selected parameters of thermal stability vs. crystallization has been studied by differential thermal analysis. Structural analysis was provided by X–ray diffraction. The order of thermal stability vs. crystallization representing of activation energy of studied glass systems which increase with higher addition both oxides. The same order was obtained from the values of XRD. On the comparison the glasses with zero addition titanium dioxide their activation energy was much higher.

Raman and dielectric response of BaTi1-x(Mg1/3Nb2/3)xO3 solid solution

2013 ◽  
Vol 03 (04) ◽  
pp. 1350030 ◽  
Author(s):  
Jingji Zhang ◽  
Ludong Ji ◽  
Jiangying Wang
Keyword(s):  
Activation Energy ◽  
Solid Solution ◽  
Raman Spectroscopy ◽  
Dielectric Response ◽  
Critical Concentration ◽  
Structural Evolution ◽  
Dielectric Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermally Activated

Structural evolution and dielectric analysis have been performed for BaTi 1-x( Mg 1/3 Nb 2/3)x O 3 solid solutions with x ≤ 0.07, together with the analysis of Raman spectroscopy. X-Ray diffraction and Raman results show a structural evolution from a tetragonal phase to a cubic one with increasing x. Dielectric analysis reveals a low critical concentration corresponding to ferroelectric–relaxor crossover (xc = 0.05). Activation energy with dozens meV is obtained using the Vogel–Fulcher relationship, which is attributed to thermally activated off-center ion hopping.

RNA polymerase: Preparation and structural analysis of helical polymers

1984 ◽  
Vol 42 ◽  
pp. 152-153
Author(s):  
E. Loren Buhle ◽  
Pamela Rew ◽  
Ueli Aebi
Keyword(s):  
Structural Analysis ◽  
Rna Polymerase ◽  
Molecular Level ◽  
X Ray Diffraction ◽  
Helical Polymers ◽  
X Ray ◽  
E Coli ◽  
The Past ◽  
Ordered Arrays ◽  
Low Ionic Strength

While DNA-dependent RNA polymerase represents one of the key enzymes involved in transcription and ultimately in gene expression in procaryotic and eucaryotic cells, little progress has been made towards elucidation of its 3-D structure at the molecular level over the past few years. This is mainly because to date no 3-D crystals suitable for X-ray diffraction analysis have been obtained with this rather large (MW ~500 kd) multi-subunit (α2ββ'ζ). As an alternative, we have been trying to form ordered arrays of RNA polymerase from E. coli suitable for structural analysis in the electron microscope combined with image processing. Here we report about helical polymers induced from holoenzyme (α2ββ'ζ) at low ionic strength with 5-7 mM MnCl2 (see Fig. 1a). The presence of the ζ-subunit (MW 86 kd) is required to form these polymers, since the core enzyme (α2ββ') does fail to assemble into such structures under these conditions.

scholarly journals Synthesis of Ce1−xPdxO2−δ Solid Solution in Molten Nitrate

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 640
Author(s):  
Hideaki Sasaki ◽  
Keisuke Sakamoto ◽  
Masami Mori ◽  
Tatsuaki Sakamoto
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Solid Solutions ◽  
Photoelectron Spectroscopy ◽  
Synthesis Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Co Precipitation ◽  
Ionic States

CeO2-based solid solutions in which Pd partially substitutes for Ce attract considerable attention, owing to their high catalytic performances. In this study, the solid solution (Ce1−xPdxO2−δ) with a high Pd content (x ~ 0.2) was synthesized through co-precipitation under oxidative conditions using molten nitrate, and its structure and thermal decomposition were examined. The characteristics of the solid solution, such as the change in a lattice constant, inhibition of sintering, and ionic states, were examined using X-ray diffraction (XRD), scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM−EDS), transmission electron microscopy (TEM)−EDS, and X-ray photoelectron spectroscopy (XPS). The synthesis method proposed in this study appears suitable for the easy preparation of CeO2 solid solutions with a high Pd content.

scholarly journals Structural and Raman Vibrational Studies ofCeO2-Bi2O3Oxide System

2009 ◽  
Vol 2009 ◽  
pp. 1-4 ◽  
Author(s):  
L. Bourja ◽  
B. Bakiz ◽  
A. Benlhachemi ◽  
M. Ezahri ◽  
J. C. Valmalette ◽  
...  
Keyword(s):  
Solid Solution ◽  
Raman Spectroscopy ◽  
Phase Changes ◽  
Phase System ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vibrational Studies ◽  
Coprecipitation Route

A series of ceramics samples belonging to theCeO2-Bi2O3phase system have been prepared via a coprecipitation route. The crystallized phases were obtained by heating the solid precursors at600∘Cfor 6 hours, then quenching the samples. X-ray diffraction analyses show that forx<0.20a solid solutionCe1−xBixO2−x/2with fluorine structure is formed. For x ranging between 0.25 and 0.7, a tetragonalβ′phase coexisting with the FCC solid solution is observed. For x ranging between 0.8 and 0.9, a new tetragonalβphase appears. Theβ′phase is postulated to be a superstructure of theβphase. Finally, close tox=1, the classical monoclinicα Bi2O3structure is observed. Raman spectroscopy confirms the existence of the phase changes as x varies between 0 and 1.

Structural analysis by X-ray diffraction of a non-polar alkenyl liquid crystalline compound

1996 ◽  
Vol 20 (6) ◽  
pp. 765-770 ◽  
Author(s):  
A. Nath ◽  
S. Gupta ◽  
P. Mandal ◽  
S. Paul ◽  
H. Schenk
Keyword(s):  
Structural Analysis ◽  
Liquid Crystalline ◽  
Crystalline Compound ◽  
X Ray Diffraction ◽  
X Ray ◽  
Liquid Crystalline Compound

scholarly journals X-ray Diffraction: A Powerful Technique for the Multiple-Length-Scale Structural Analysis of Nanomaterials

Crystals ◽  
2016 ◽  
Vol 6 (8) ◽  
pp. 87 ◽  
Author(s):  
Cinzia Giannini ◽  
Massimo Ladisa ◽  
Davide Altamura ◽  
Dritan Siliqi ◽  
Teresa Sibillano ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Length Scale ◽  
X Ray Diffraction ◽  
X Ray ◽  
Powerful Technique ◽  
Multiple Length Scale

Study on Phases and Thermoelectric Properties of Bulk Fe4Sb12 and Fe3CoSb12 Prepared by Milling and Sintering

2011 ◽  
Vol 121-126 ◽  
pp. 1526-1529
Author(s):  
Ke Gao Liu ◽  
Jing Li
Keyword(s):  
Thermoelectric Properties ◽  
Impurity Phase ◽  
Semiconductor Materials ◽  
Thermal Constant ◽  
X Ray Diffraction ◽  
X Ray ◽  
Seebeck Coefficients ◽  
Maximum Value ◽  
Type Semiconductor ◽  
P Type

Bulk Fe4Sb12 and Fe3CoSb12 were prepared by sintering at 600 °C. The phases of samples were analyzed by X-ray diffraction and their thermoelectric properties were tested by electric constant instrument and laser thermal constant instrument. Experimental results show that, the major phases of bulk samples are skutterudite with impurity phase FeSb2. The electric resistivities of the samples increase with temperature rising at 100~500 °C. The bulk samples are P-type semiconductor materials. The Seebeck coefficients of the bulk Fe4Sb12 are higher than those of bulk Fe3CoSb12 samples at 100~200 °C but lower at 300~500 °C. The power factor of the bulk Fe4Sb12 samples decreases with temperature rising while that of bulk Fe3CoSb12 samples increases with temperature rising at 100~500 °C. The thermal conductivities of the bulk Fe4Sb12 samples are relatively higher than those of and Fe3CoSb12, which maximum value is up to 0.0974 Wm-1K-1. The ZT value of bulk Fe3CoSb12 increases with temperature rising at 100~500 °C, the maximum value is up to 0.031.The ZT values of the bulk Fe4Sb12 samples are higher than those of bulk Fe3CoSb12 at 100~300 °C while lower at 400~500 °C.

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