A transmission electron microscopic study of structural transitions in fast ionic conductors

1987 ◽  
Vol 45 ◽  
pp. 156-157
Author(s):  
R. B. Queenan ◽  
P. K. Davies
Keyword(s):  
Optical Properties ◽  
Ionic Conduction ◽  
Recent Observation ◽  
Ionic Conductivities ◽  
Sodium Aluminate ◽  
Two Dimensions ◽  
Ionic Conductors ◽  
Electron Microscopic ◽  
Transmission Electron ◽  
Trivalent Cations

Na ß“-alumina (Na1.67Mg67Al10.33O17) is a non-stoichiometric sodium aluminate which exhibits fast ionic conduction of the Na+ ions in two dimensions. The Na+ ions can be exchanged with a variety of mono-, di-, and trivalent cations. The resulting exchanged materials also show high ionic conductivities.Considerable interest in the Na+-Nd3+-ß“-aluminas has been generated as a result of the recent observation of lasing in the pulsed and cw modes. A recent TEM investigation on a 100% exchanged Nd ß“-alumina sample found evidence for the intergrowth of two different structure types. Microdiffraction revealed an ordered phase coexisting with an apparently disordered phase, in which the cations are completely randomized in two dimensions. If an order-disorder transition is present then the cooling rates would be expected to affect the microstructures of these materials which may in turn affect the optical properties. The purpose of this work was to investigate the affect of thermal treatments upon the micro-structural and optical properties of these materials.

SYNTHESIS AND CHARACTERIZATON OF HIGH-QUALITY GaN NANORODS WITH TRIANGULAR CROSS SECTION

2005 ◽  
Vol 19 (15n17) ◽  
pp. 2859-2864 ◽  
Author(s):  
X. X. WU ◽  
J. J. FU ◽  
Y. YANG ◽  
Q. WU ◽  
Z. HU ◽  
...  
Keyword(s):  
Optical Properties ◽  
Cross Section ◽  
Optoelectronic Devices ◽  
Hexagonal Structure ◽  
Electron Microscopic ◽  
High Quality ◽  
Triangular Cross Section ◽  
Transmission Electron ◽  
Transmission Electron Microscopic ◽  
Potential Applications

High-quality GaN nanorods with triangular cross section were synthesized via a simple chloride-assisted vapor phase epitaxy method. High-resolution transmission electron microscopic observations show that the synthesized GaN nanorods are single crystal with wurtzite hexagonal structure. Raman and photoluminescence measurements were also carried out to study the optical properties of the as-prepared GaN nanorods, which suggests the potential applications in optoelectronic devices.

Ionic Conduction Performance of Solid Electrolyte Materials

2010 ◽  
Vol 156-157 ◽  
pp. 799-802
Author(s):  
Ming Zhou ◽  
Yan Wen Tian
Keyword(s):  
Experimental Data ◽  
Ionic Conductivity ◽  
Solid Electrolyte ◽  
Ionic Conduction ◽  
Sol Gel ◽  
Ionic Conductivities ◽  
Microwave Method ◽  
Ionic Conductors ◽  
Base Materials ◽  
Polycrystalline Powder

This experiment composes irreversible cells using ultrafine electrolyte materials and platinum slices, to measure the ionic conductivity the cells at normal temperatures with the help of impedance 1286 spectroscopy. We have calculated the ionic conductivities, which indicate that the ionic conductivities of the merchant LaF3 polycrystalline powder and the powder by microwave method are higher than the ones of LaF3 crystal and the powder by Sol-Gel method, to achieve 10-6 Scm-1, so, they are better ionic conductors at normal temperature and can be used as sensor base materials. The experimental data show that O- participates in ionic conduction.

Bi2Sr2M'2M”O11.5 [(M' = Nb, Ta) and (M” = Al, Ga)], Synthesis and Characterization of Oxygen-Deficient Aurivillius Phases

1994 ◽  
Vol 369 ◽  
Author(s):  
Kurt R. Kendall ◽  
Carlos J. Navas ◽  
Hans-Conrad Zur Loye
Keyword(s):  
Ionic Conductivities ◽  
Transference Number ◽  
Atmospheric Conditions ◽  
New Materials ◽  
Ionic Conductors ◽  
X Ray Diffraction ◽  
Aurivillius Phases ◽  
Arrhenius Plots ◽  
Transmission Electron

AbstractOxygen-deficient layered bismuth oxides, Bi2Sr2M'2M”O11.5 [(M' = Nb, Ta) and (M” = Al, Ga)] were synthesized. Powder X-ray diffraction and transmission electron microscopy were usedto characterize the new materials' structures. The ionic conductivity was measuredusing impedance spectroscopy which indicated the existence of multiple conductive states in the new oxygen-deficient materials. Arrhenius plots of the conductivity showed discontinuities which were attributed to transitions between different conductive states. At 800ºC, Bi2Sr2Nb2GaO11.5 and Bi2Sr2Nb2A1O1.5, have ionic conductivities of 2.0×10−2 S/cm and 1.2×10−2 S/cm, respectively. Differential thermal analysis showed phase transitions in the oxygen-deficient materials. These transitionsoccurred at temperatures similar to those at which discontinuities were observed in the Arrhenius plots of the conductivity and are attributed to oxygen vacancy order/disorder transitions. The transference number was calculated for some of the samples by measuring both the EMF and the conductivity as a function of oxygen partial pressure. Under atmospheric conditions the new materials are predominantly ionic conductors.

OPTICAL PROPERTIES OF CARBON CLUSTERS EMBEDDED IN SiO2 FILMS

1996 ◽  
Vol 03 (01) ◽  
pp. 1095-1100 ◽  
Author(s):  
S. HAYASHI ◽  
M. KATAOKA ◽  
H. KOSHIDA ◽  
K. YAMAMOTO
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Annealing Temperature ◽  
Interstellar Extinction ◽  
Carbon Clusters ◽  
Electron Microscopic ◽  
Carbon Doped ◽  
Transmission Electron ◽  
Transmission Electron Microscopic ◽  
Deposited Films

Raman spectra were measured for carbon-doped SiO 2 thin films prepared by an rf cosputtering method. The changes in the spectra were systematically studied as a function of the annealing temperature. From a detailed analysis of the spectra, the following conclusions were drawn. In the as-deposited films, very small carbon clusters are embedded in the SiO 2 matrices. When the films are annealed at 600°C, graphite-like sp 2 bonds begin to develop in the clusters. Upon annealing with higher temperatures, the size of sp 2 bond clusters increases. However, the growth of graphite microcrystals can be ruled out, since high-resolution transmission electron microscopic images of the samples annealed at 1000°C do not show lattice fringes due to graphite microcrystals. The samples annealed at 1000°C were found to exhibit an extinction hump around 220 nm, very similar to that seen in the interstellar extinction spectra.

Retracted Article: Doping, strain, defects and magneto-optical properties of Zn1−xMnxO nanocrystals

CrystEngComm ◽  
2013 ◽  
Vol 15 (22) ◽  
pp. 4438-4447 ◽  
Author(s):  
Prashant K. Sharma ◽  
Ranu K. Dutta ◽  
R. J. Choudhary ◽  
Avinash C. Pandey
Keyword(s):  
Optical Properties ◽  
Electron Microscopic ◽  
Digital Photograph ◽  
Mn Doping ◽  
Liquid Suspension ◽  
Transmission Electron ◽  
Transmission Electron Microscopic ◽  
Retracted Article ◽  
Uv Lamp ◽  
Lattice Planes

High resolution transmission electron microscopic images of ZnO:Mn2+ nanoparticles, for (a) 10% Mn doping, showing defect free regular atomic arrangement, and (b) 20% Mn doping, irregular lattice planes with significant defects. (c) Digital photograph of liquid suspension of ZnO:Mn2+ nanocrystals under UV lamp. (d) MH loop of ZnO:Mn2+ nanoparticles.

Nonlinear optical properties of Ag-enriched ZnO nanostructures

2019 ◽  
Vol 28 (03) ◽  
pp. 1950027 ◽  
Author(s):  
Emusani Ramya ◽  
M. Veeramohan Rao ◽  
D. Narayana Rao
Keyword(s):  
Optical Properties ◽  
Nonlinear Optical ◽  
Visible Region ◽  
Picosecond Laser ◽  
Nonlinear Optical Properties ◽  
Zno Nps ◽  
Electron Microscopic ◽  
Two Photon ◽  
Transmission Electron ◽  
Novel Method

Ag-enriched ZnO nanoparticles (NPs) are prepared by using silver nitrate, zinc acetate, and N,N-dimethylformamide (DMF) as source elements, a novel method under particular conditions without any additives added as stabilizing or reducing agent. The transmission electron microscopic (TEM) studies reveal that the ZnO layer is well formed onto the Ag core. The photoluminescence shows the energy transfer and electron-hole recombination between the conductor and semiconductor layers. Nonlinear optical properties are studied by using picosecond laser. Nonlinear absorption values are increased by increasing the Ag concentration in Ag-enriched ZnO NPs. Nonlinear optical effects in Ag-enriched ZnO NPs are due to two-photon induced free carrier and inter-band transitions. Optical limiting characteristics are measured in the picosecond time domain. Ag-enriched ZnO NPs are used as optical limiters in the visible region.

The Optical Properties of ION Implanted Silica

1997 ◽  
Vol 504 ◽  
Author(s):  
C. C. Smith ◽  
D. Ila ◽  
E. K. Williams ◽  
D. B. Poker ◽  
D. K. Hensley
Keyword(s):  
Optical Properties ◽  
Absorption Band ◽  
Optical Absorption ◽  
Electron Microscopic ◽  
Absorption Bands ◽  
Optical Absorption Band ◽  
Transmission Electron ◽  
Transmission Electron Microscopic ◽  
Before And After ◽  
Microscopic Techniques

ABSTRACTWe present the results of our investigation of the change in the optical properties of silica, "suprasil", after keV through MeV implantation of copper, tin, silver and gold and after annealing. Suprasil, name brand of silica glass produced by Hereaus Amersil, which is chemically highly pure with well known optical properties. Both linear and nonlinear optical properties of the implanted silica were investigated before and after thermal annealing. All implants showed strong optical absorption bands in agreement with Mie theory. For implants with a measurable optical absorption band we used Doyle's theory and the full width half maximum of the absorption band to calculate the predicted size of the formed nanoclusters at various heat treatment temperatures. These results are compared with those obtained from direct observation using transmission electron microscopic techniques.

A Reproducible Selective Stain for Cardiac Sarcoplasmic Reticulum

1974 ◽  
Vol 32 ◽  
pp. 214-215
Author(s):  
R. A. Waugh ◽  
J. R. Sommer
Keyword(s):  
Complex System ◽  
Electron Microscope ◽  
Sarcoplasmic Reticulum ◽  
Transmission Electron Microscope ◽  
Electron Microscopic ◽  
Cardiac Sarcoplasmic Reticulum ◽  
Transmission Electron

Cardiac sarcoplasmic reticulum (SR) is a complex system of intracellular tubules that, due to their small size and juxtaposition to such electron-dense structures as mitochondria and myofibrils, are often inconspicuous in conventionally prepared electron microscopic material. This study reports a method with which the SR is selectively “stained” which facilitates visualizationwith the transmission electron microscope.

Transmission Electron Microscopy of Protein Macromolecules

1971 ◽  
Vol 29 ◽  
pp. 424-425
Author(s):  
Henry S. Slayter
Keyword(s):  
Biological Systems ◽  
Metal Vapor ◽  
Resolving Power ◽  
Electron Microscopic ◽  
Chemical Methods ◽  
Molecular Weights ◽  
The Past ◽  
Physical Chemical ◽  
Transmission Electron

Electron microscopic methods have been applied increasingly during the past fifteen years, to problems in structural molecular biology. Used in conjunction with physical chemical methods and/or Fourier methods of analysis, they constitute powerful tools for determining sizes, shapes and modes of aggregation of biopolymers with molecular weights greater than 50, 000. However, the application of the e.m. to the determination of very fine structure approaching the limit of instrumental resolving power in biological systems has not been productive, due to various difficulties such as the destructive effects of dehydration, damage to the specimen by the electron beam, and lack of adequate and specific contrast. One of the most satisfactory methods for contrasting individual macromolecules involves the deposition of heavy metal vapor upon the specimen. We have investigated this process, and present here what we believe to be the more important considerations for optimizing it. Results of the application of these methods to several biological systems including muscle proteins, fibrinogen, ribosomes and chromatin will be discussed.

An electron microscopic study of the intra-myocardial lesions in cases of acute myocardial infarction

1978 ◽  
Vol 36 (2) ◽  
pp. 484-485
Author(s):  
Masahiro Ono ◽  
Kaoru Aihara ◽  
Gompachi Yajima
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Coronary Vessels ◽  
Vascular Wall ◽  
Vascular Changes ◽  
Electron Microscopic ◽  
Main Trunk ◽  
Mechanical Destruction ◽  
Transmission Electron ◽  
Myocardial Lesions

The pathogenesis of the arteriosclerosis in the acute myocardial infarction is the matter of the extensive survey with the transmission electron microscopy in experimental and clinical materials. In the previous communication,the authors have clarified that the two types of the coronary vascular changes could exist. The first category is the case in which we had failed to observe no occlusive changes of the coronary vessels which eventually form the myocardial infarction. The next category is the case in which occlusive -thrombotic changes are observed in which the myocardial infarction will be taken placed as the final event. The authors incline to designate the former category as the non-occlusive-non thrombotic lesions. The most important findings in both cases are the “mechanical destruction of the vascular wall and imbibition of the serous component” which are most frequently observed at the proximal portion of the coronary main trunk.

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