Low-Temperature Multistep Topotactic Routes to New Mixed-Valence Perovskites

1998 ◽  
Vol 547 ◽  
Author(s):  
J.N. Lalena ◽  
R.A. McIntyre ◽  
B.L. Cushing ◽  
K.A. Thomas ◽  
J.L. Heintz ◽  
...  
Keyword(s):  
Mixed Valence ◽  
Single Layer ◽  
Mixed Valency ◽  
Complex Samples ◽  
Triple Layer ◽  
Metastable Compounds ◽  
Layered Perovskites ◽  
Layer Series ◽  
Electronic Behavior

AbstractMultistep topotactic routes are exploited to introduce mixed-valency into mixed-metal oxides at low temperatures (≤ 350°C). A new set of single- and triple-layered perovskites, Na1-x-yCax/2LaTiO4 and Na2-x+yCax/2La2Ti3O10, respectively, has been prepared by a combination of ion exchange and reductive intercalation. The single-layer series are metastable compounds. The magnetic and electronic behavior of the triple-layer titanate is consistent with Anderson localization effects, while those of the single-layer materials are more complex; samples demonstrate “Hurd-like” conductivity and an unusual magnetic response. The details of the synthesis and characterization of these materials are presented and their magnetic and electronic behavior discussed.

X-Ray Fluorescence Analysis of Multi-Layer Thin Films

1985 ◽  
Vol 29 ◽  
pp. 395-402 ◽  
Author(s):  
T. C. Huang ◽  
W. Parrish
Keyword(s):  
Thin Films ◽  
Single Layer ◽  
Fluorescence Analysis ◽  
Parameter Method ◽  
Fundamental Parameter ◽  
X Ray ◽  
Triple Layer ◽  
Layer Thin Film ◽  
Fundamental Parameter Method

AbstractThe characterization of multi-layer thin films by X-ray fluorescence using the fundamental parameter method and the LAMA-III program is described. Analyses of a double-layer FeMn/NiFe and two triple-layer NiFe/Cu/Cr and Cr/Cu/NiFe specimens show that the complex inter-layer absorption and secondary fluorescence effects were properly corrected. The compositions and thicknesses of all layers agreed to ±2% with corresponding single-layer films, a precisian comparable with bulk and single-layer thin film analyses.

Characterization of a monolayer graphitic structure

1994 ◽  
Vol 52 ◽  
pp. 760-761
Author(s):  
X. Lin ◽  
X. K. Wang ◽  
V. P. Dravid ◽  
J. B. Ketterson ◽  
R. P. H. Chang
Keyword(s):  
Three Dimensional ◽  
Single Layer ◽  
Synthesis Process ◽  
Graphitic Structure ◽  
Positive Gaussian Curvature ◽  
Graphitic Sheet ◽  
Structural And Electronic Properties ◽  
New Material ◽  
Hexagonal Network

For small curvatures of a graphitic sheet, carbon atoms can maintain their preferred sp2 bonding while allowing the sheet to have various three-dimensional geometries, which may have exotic structural and electronic properties. In addition the fivefold rings will lead to a positive Gaussian curvature in the hexagonal network, and the sevenfold rings cause a negative one. By combining these sevenfold and fivefold rings with sixfold rings, it is possible to construct complicated carbon sp2 networks. Because it is much easier to introduce pentagons and heptagons into the single-layer hexagonal network than into the multilayer network, the complicated morphologies would be more common in the single-layer graphite structures. In this contribution, we report the observation and characterization of a new material of monolayer graphitic structure by electron diffraction, HREM, EELS.The synthesis process used in this study is reported early. We utilized a composite anode of graphite and copper for arc evaporation in helium.

Structural, electrical characterization and oxygen-diffusion paths in LaSrGa1-xMgxO4-δ (x=0.0-0.2) layered perovskites: an impedance spectroscopy and neutron diffraction study

2021 ◽  
Author(s):  
Carlos Marino ◽  
Juan Basbus ◽  
Ana L. Larralde ◽  
Jose Antonio Alonso ◽  
Maria Teresa Fernandez-Diaz ◽  
...  
Keyword(s):  
Impedance Spectroscopy ◽  
Neutron Diffraction ◽  
Structural Characterization ◽  
Oxygen Diffusion ◽  
Electrical Characterization ◽  
Neutron Diffraction Study ◽  
Oxygen Ions ◽  
Diffusion Paths ◽  
Layered Perovskites

This work presents the results of the structural characterization of LaSrGa1-xMgxO4-δ oxides with x=0.0-0.2 (LSGM'); these oxides with layered K2NiF4-type structure are potential electrolytes of oxygen ions with applications in...

scholarly journals Kinetics of slow release of nitrogen fertiliser from multi-layered nanofibrous structures

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Leila Javazmi ◽  
Anthony Young ◽  
Gavin J. Ash ◽  
Tobias Low
Keyword(s):  
Crop Production ◽  
Slow Release ◽  
New Technology ◽  
Single Layer ◽  
Middle Layer ◽  
Modern Agriculture ◽  
Triple Layer ◽  
Urea Release ◽  
Electrospun Nanofibres ◽  
Kinetics Of

AbstractFertilisers are essential in modern agriculture to enhance plant growth, crop production and product quality. Recent research has focused on the development of delivery systems designed to prolong fertiliser release. This study introduces a new technology to encapsulate and release molecules of fertilisers by using multi-layered electrospun nanofibre as a carrier. Single-layer poly L-lactic acid (PLLA) nanofibres loaded with urea were fabricated using electrospinning. Triple-layer nanofibrous structures were produced by electrospinning polyhydroxybutyrate (PHB) nanofibres as external layers with PLLA nanofibres impregnated with urea fertiliser as the middle layer. Scanning electron microscopy (SEM) and Fourier transform infrared spectrophotometry (FTIR) were employed to characterize the morphology of electrospun nanofibres. Urea release dynamic was analysed using a total nitrogen instrument (TNM-1). The results indicated that triple-layered urea-impregnated nanofibrous structures led to lower initial rate of nitrogen release and slower release rate of cumulative nitrogen which extended for more than three months. It is concluded that triple-layer nanofibrous structures have the potential for slow release delivery of fertilisers.

Thermal decomposition of multilayer honeycomb core laminate sandwich composite panels in cone calorimeter apparatus – Effect of the top decomposed layer

2021 ◽  
pp. 002199832199087
Author(s):  
Hussain Najmi ◽  
Jocelyn Luche ◽  
Thomas Rogaume
Keyword(s):  
Cone Calorimeter ◽  
Single Layer ◽  
Heat Fluxes ◽  
Decomposition Process ◽  
Phase Iii ◽  
Sandwich Composite ◽  
Back Surface ◽  
Multilayer Composite ◽  
In Fire

Multilayer composite materials are frequently used in aircraft interiors. Even though they have high properties (such as physical, chemical and mechanical properties), their application is limited due to lack of knowledge of their decomposition process and on the interaction between different layers in fire. In the present work, two types of composites with 3 and 4 layers are studied. The fire characterization of multilayer composite is studied in 3 different phases using ISO-5660 cone calorimeter at two heat fluxes (35 and 50 kW.m−2). Phase-I mainly concentrates on the decomposition of single layer materials (paint, laminate and honeycomb) while in phase-II and phase-III, different assemblies are formed using a single layer material and studied in the same experimental configuration. In all the three phases, back surface temperatures of the materials or assemblies are measured and analyzed with different gas productions which allow to understand the dynamics of the decomposition process. The finding from the cone calorimeter study suggests that the ignition primarily depends on the top layer behavior of the composite. The permeability analysis on the top layer of the composite confirms that decomposed layer of paint offers more resistance to the volatile gases escaping from the composite. At the end of the study, thermal conductivity is determined and the ignition temperature of both the composite is determined.

Construction of Copper Halide Networks within Layered Perovskites. Syntheses and Characterization of New Low-Temperature Copper Oxyhalides

2001 ◽  
Vol 40 (4) ◽  
pp. 710-714 ◽  
Author(s):  
Thomas A. Kodenkandath ◽  
Amar S. Kumbhar ◽  
Weilie L. Zhou ◽  
John B. Wiley
Keyword(s):  
Low Temperature ◽  
Copper Halide ◽  
Layered Perovskites

scholarly journals Synthesis and Characterization of New Mixed-Metal Triple-Layered Perovskites, Na2La2Ti3-xRuxO10(x≤ 1.0).

2000 ◽  
Vol 12 (11) ◽  
pp. 3526-3526
Author(s):  
John N. Lalena ◽  
Alexander U. Falster ◽  
William B. Simmons ◽  
Everett E. Carpenter ◽  
Jason Wiggins ◽  
...  
Keyword(s):  
Synthesis And Characterization ◽  
Mixed Metal ◽  
Layered Perovskites

Characterization of Glass-Ceramics by TEM

2013 ◽  
Vol 562-565 ◽  
pp. 809-812 ◽  
Author(s):  
Xiao Qing Liu ◽  
Jun Lin Xie ◽  
Feng He ◽  
Hu Yang
Keyword(s):  
Electron Beam ◽  
Carbon Film ◽  
Glass Ceramics ◽  
Single Layer ◽  
Double Layers ◽  
Characterization Technique

The characterization technique of glass-ceramics by TEM was discussed by comparing the effects of single layer carbon film technique and double layers carbon film technique on the microstructure of Li-Al-Si glass-ceramics. The results show that double layers carbon film technique can improve glass-ceramics sample’s conductivity, reduce the induction of elctron beam on glass-ceramics, and avoid the temperature increasing of glass-ceramics particles caused by the charges aggregation on the particles’ surface when TEM electron beam hit down, prevent glass-ceramics from crystallization and the transformation of microstructurec. So, compared with single layer carbon film technique, double layers carbon film technique is more suitable for the research of microsture of glass-ceramics by TEM.

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