scholarly journals Structural analysis of oxide ion conductor, Ba2-xSrxIn2O5 and Ba2In2-xGaxO5 - Significance of synchrotron X-ray diffraction at high temperatures

2009 ◽  
Vol 117 (1361) ◽  
pp. 56-59 ◽  
Author(s):  
Takuya HASHIMOTO ◽  
Masashi YOSHINAGA ◽  
Koutatsu NAKANO ◽  
Kazuki OMOTO ◽  
Takayuki SUGIMOTO ◽  
...  
Keyword(s):  
Structural Analysis ◽  
High Temperatures ◽  
X Ray Diffraction ◽  
Ion Conductor ◽  
X Ray ◽  
Oxide Ion Conductor ◽  
Oxide Ion

Determinations of crystallographic space group and atomic arrangements in oxide-ion-conducting Nd9.33(SiO4)6O2

2004 ◽  
Vol 219 (1) ◽  
Author(s):  
Hiroki Okudera ◽  
Akira Yoshiasa ◽  
Yuji Masubuchi ◽  
Mikio Higuchi ◽  
Shinichi Kikkawa
Keyword(s):  
Single Crystal ◽  
Diffraction Study ◽  
X Ray Diffraction ◽  
Ion Conductor ◽  
Space Group ◽  
X Ray ◽  
Oxide Ion Conductor ◽  
Ion Conducting ◽  
Oxide Ion

AbstractIn this paper we report single crystal X-ray diffraction study of an oxide-ion-conductor Nd

Structural and Electrical Changes in BIMNVOX Oxide-Ion Conductor

2011 ◽  
Vol 316-317 ◽  
pp. 7-22 ◽  
Author(s):  
Saba Beg ◽  
Shehla Hafeez ◽  
Niyazi A.S. Al-Areqi
Keyword(s):  
Solid Solutions ◽  
X Ray Diffraction ◽  
Structural Investigations ◽  
Ion Conductor ◽  
Polymorphic Transitions ◽  
Oxide Ion Conductor ◽  
Β Phase ◽  
Ft Ir ◽  
Increasing Temperature ◽  
Oxide Ion

Ceramic solid solutions Bi4MnxV2–xO11–(x/2)–δ in the composition range 0.07 ≤ x ≤ 0.30 were obtained by solid state synthesis. Structural investigations were carried out by using a combination of FT-IR and powder X-ray diffraction technique. Polymorphic transitions (β↔γ and γ′↔γ) were detected by DTA and variation in the Arrhenius plots of conductivity. The solid solutions with composition 0.07 ≤ x ≤ 0.17 are isostructural with the orthorhombic β-phase, and those with x ≤ 0.30 represent tetragonal γ-phase. With increasing Mn concentration, the conductivity of solid solutions increases from 3.684×10-6 (x = 0.07) to 2.467×10-5 (x = 0.17). AC impedance plots show that the conductivity is mainly due to the grain contribution which is evident in the enhanced short range diffusion of oxide ion vacancy in the grains with increasing temperature.

Synthesis and Impedance Spectroscope of B-Doped La9.33+x/3(SiO4)6-x(BO4)xO2 Apatite Oxide Ion Conductor

2017 ◽  
Vol 904 ◽  
pp. 102-106
Author(s):  
Zhao Xiang Huang ◽  
Kan Yu ◽  
Jun Liang ◽  
Xiao Li Sheng
Keyword(s):  
Solid State ◽  
Powder Diffraction ◽  
Single Phase ◽  
Apatite Structure ◽  
Ion Conductor ◽  
X Ray ◽  
Oxide Ion Conductor ◽  
Conductivity Enhancement ◽  
Oxide Ion

B2O3 was doped into the oxide ion conductor La9.33(SiO4)6O2 according to the formula La9.33+x/3(SiO4)6-x(BO4)xO2 where 0 ≤ x ≤ 2. Samples were prepared by solid state reaction; difficulty was experienced in obtaining fully homogenised products at intermediate x, although they were nominally single-phase by X-ray powder diffraction. A small conductivity enhancement was observed at intermediate B content which further illustrates the important role of La vacancies in optimising the conductivity of La silicates with the apatite structure.

Properties of La2-xSrxMo2-yWyO9-δ Oxide-Ion Conductor Synthesized by Citrate Gel Method

2010 ◽  
Vol 93-94 ◽  
pp. 509-512
Author(s):  
Witoon Thepsuwan ◽  
Sutin Kuharuangrong
Keyword(s):  
Oxidation State ◽  
Single Phase ◽  
Edge Structure ◽  
Ion Conductor ◽  
Gel Method ◽  
X Ray ◽  
Oxide Ion Conductor ◽  
Average Grain Size ◽  
X Ray Absorption ◽  
Oxide Ion

Properties of La2-xSrxMo2-yWyO9-δ (x = 0-0.2, y = 0-0.3) synthesized via citrate gel method have been investigated on phase, oxidation state, microstructure and electrical conductivity. The XRD results show a single phase after calcination at 700 oC for all compositions. The oxidation state of Mo in La2-xSrxMo2-yWyO9-δ compositions determined by X-ray Absorption Near Edge Structure (XANES) is found to be +6. The average grain size of sintered compositions increases with the amount of Sr but slightly decreases with an addition of W. At 500 oC, all doped compositions exhibit higher conductivity as compared to 5.42×10-4 S∙cm-1 for undoped-La2Mo2O9. In this work, the composition of La1.9Sr0.1Mo2O9-δ performs the highest conductivity value of 1.95×10-3 S∙cm-1.

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 The impact of point defects in n-type GaN layers on thermal decomposition of InGaN/GaN QWs

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mikolaj Grabowski ◽  
Ewa Grzanka ◽  
Szymon Grzanka ◽  
Artur Lachowski ◽  
Julita Smalc-Koziorowska ◽  
...  
Keyword(s):  
Quantum Wells ◽  
High Temperatures ◽  
Point Defects ◽  
X Ray Diffraction ◽  
Helium Ions ◽  
X Ray ◽  
Sapphire Substrates ◽  
Transmission Electron ◽  
The Impact ◽  
Ingan Quantum Wells

AbstractThe aim of this paper is to give an experimental evidence that point defects (most probably gallium vacancies) induce decomposition of InGaN quantum wells (QWs) at high temperatures. In the experiment performed, we implanted GaN:Si/sapphire substrates with helium ions in order to introduce a high density of point defects. Then, we grew InGaN QWs on such substrates at temperature of 730 °C, what caused elimination of most (but not all) of the implantation-induced point defects expanding the crystal lattice. The InGaN QWs were almost identical to those grown on unimplanted GaN substrates. In the next step of the experiment, we annealed samples grown on unimplanted and implanted GaN at temperatures of 900 °C, 920 °C and 940 °C for half an hour. The samples were examined using Photoluminescence, X-ray Diffraction and Transmission Electron Microscopy. We found out that the decomposition of InGaN QWs started at lower temperatures for the samples grown on the implanted GaN substrates what provides a strong experimental support that point defects play important role in InGaN decomposition at high temperatures.

Sign in / Sign up

Export Citation Format

Share Document