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.

Characterization of Interfacial Layer of DUV Coatings by Spectroscopic Ellipsometry

2013 ◽  
Vol 662 ◽  
pp. 277-283
Author(s):  
Wen Yuan Deng
Keyword(s):  
Spectroscopic Ellipsometry ◽  
Interfacial Layer ◽  
Single Layer ◽  
Double Layers ◽  
Optical Index ◽  
Variable Angle ◽  
Layer Sample ◽  
Deep Ultraviolet ◽  
Variable Angle Spectroscopic Ellipsometry

The Interfacial layer has an important influence on the optical performance of the deep ultraviolet (DUV) coatings. The variable angle Spectroscopic ellipsometry measurements of three kinds of DUV coating samples were performed in the wavelength range 150-500nm using a purged variable angle Spectroscopic ellipsometer. The samples include the single layer sample, double layers sample, and three layers sample. The thickness and optical index of the MgF2 layer and LaF3 layer as well as those of the interfacial layer between them were obtained by successful regression of the SE measurements. For the single layer, the agreement of the results between the SE and the spectrophotometic techniques was very good. The obtained thickness of the two kinds of interfacial layer was in consistent with the RMS results of the single layer obtained by AFM, indicating the obtained results were reliable.

A very rapid in situ Kikuchi technique to determine relative crystal misorientation

1988 ◽  
Vol 46 ◽  
pp. 830-831
Author(s):  
J. I. Bennetch
Keyword(s):  
Electron Beam ◽  
Analytical Techniques ◽  
Superplastic Forming ◽  
The Other ◽  
Kikuchi Pattern ◽  
Kikuchi Line ◽  
Line Analysis

In a recent study of the superplastic forming (SPF) behavior of certain Al-Li-X alloys, the relative misorientation between adjacent (sub)grains proved to be an important parameter. It is well established that the most accurate way to determine misorientation across boundaries is by Kikuchi line analysis. However, the SPF study required the characterization of a large number of (sub)grains in each sample to be statistically meaningful, a very time-consuming task even for comparatively rapid Kikuchi analytical techniques.In order to circumvent this problem, an alternate, even more rapid in-situ Kikuchi technique was devised, eliminating the need for the developing of negatives and any subsequent measurements on photographic plates. All that is required is a double tilt low backlash goniometer capable of tilting ± 45° in one axis and ± 30° in the other axis. The procedure is as follows. While viewing the microscope screen, one merely tilts the specimen until a standard recognizable reference Kikuchi pattern is centered, making sure, at the same time, that the focused electron beam remains on the (sub)grain in question.

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.

Cracking at the fold in double layer coated paper: the influence of latex and starch composition

TAPPI Journal ◽  
2019 ◽  
Vol 18 (2) ◽  
pp. 93-99
Author(s):  
SEYYED MOHAMMAD HASHEMI NAJAFI ◽  
DOUGLAS BOUSFIELD, ◽  
MEHDI TAJVIDI
Keyword(s):  
Mechanical Properties ◽  
Double Layer ◽  
Starch Content ◽  
Single Layer ◽  
Double Layers ◽  
Coated Paper ◽  
Coated Papers ◽  
Coating Layers ◽  
Scanned Images ◽  
Packaging Paper

Cracking at the fold of publication and packaging paper grades is a serious problem that can lead to rejection of product. Recent work has revealed some basic mechanisms and the influence of various parameters on the extent of crack area, but no studies are reported using coating layers with known mechanical properties, especially for double-coated systems. In this study, coating layers with different and known mechanical properties were used to characterize crack formation during folding. The coating formulations were applied on two different basis weight papers, and the coated papers were folded. The binder systems in these formulations were different combinations of a styrene-butadiene latex and mixtures of latex and starch for two different pigment volume concentrations (PVC). Both types of papers were coated with single and double layers. The folded area was scanned with a high-resolution scanner while the samples were kept at their folded angle. The scanned images were analyzed within a constant area. The crack areas were reported for different types of papers, binder system and PVC values. As PVC, starch content, and paper basis weight increased, the crack area increased. Double layer coated papers with high PVC and high starch content at the top layer had more cracks in comparison with a single layer coated paper, but when the PVC of the top layer was low, cracking area decreased. No measurable cracking was observed when the top layer was formulated with a 100% latex layer.

Characterization of AA7075/AA5356 gradient transition zone in an electron beam wire-feed additive manufactured sample

2021 ◽  
Vol 172 ◽  
pp. 110867
Author(s):  
V. Utyaganova ◽  
A. Filippov ◽  
S. Tarasov ◽  
N. Shamarin ◽  
D. Gurianov ◽  
...  
Keyword(s):  
Electron Beam ◽  
Transition Zone ◽  
Feed Additive ◽  
Wire Feed

scholarly journals Double layers in the downward current region of the aurora

2003 ◽  
Vol 10 (1/2) ◽  
pp. 45-52 ◽  
Author(s):  
R. E. Ergun ◽  
L. Andersson ◽  
C. W. Carlson ◽  
D. L. Newman ◽  
M. V. Goldman
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Phase Space ◽  
Electric Field ◽  
Electric Fields ◽  
Double Layers ◽  
Parallel Electric Field ◽  
Electrostatic Waves ◽  
Current Region ◽  
Decisive Evidence

Abstract. Direct observations of magnetic-field-aligned (parallel) electric fields in the downward current region of the aurora provide decisive evidence of naturally occurring double layers. We report measurements of parallel electric fields, electron fluxes and ion fluxes related to double layers that are responsible for particle acceleration. The observations suggest that parallel electric fields organize into a structure of three distinct, narrowly-confined regions along the magnetic field (B). In the "ramp" region, the measured parallel electric field forms a nearly-monotonic potential ramp that is localized to ~ 10 Debye lengths along B. The ramp is moving parallel to B at the ion acoustic speed (vs) and in the same direction as the accelerated electrons. On the high-potential side of the ramp, in the "beam" region, an unstable electron beam is seen for roughly another 10 Debye lengths along B. The electron beam is rapidly stabilized by intense electrostatic waves and nonlinear structures interpreted as electron phase-space holes. The "wave" region is physically separated from the ramp by the beam region. Numerical simulations reproduce a similar ramp structure, beam region, electrostatic turbulence region and plasma characteristics as seen in the observations. These results suggest that large double layers can account for the parallel electric field in the downward current region and that intense electrostatic turbulence rapidly stabilizes the accelerated electron distributions. These results also demonstrate that parallel electric fields are directly associated with the generation of large-amplitude electron phase-space holes and plasma waves.

Defect Agglomeration and Electron-Beam-Induced Local-Phase Transformations in Single-Layer MoTe2

2021 ◽  
Author(s):  
Janis Köster ◽  
Mahdi Ghorbani-Asl ◽  
Hannu-Pekka Komsa ◽  
Tibor Lehnert ◽  
Silvan Kretschmer ◽  
...  
Keyword(s):  
Electron Beam ◽  
Phase Transformations ◽  
Single Layer ◽  
Local Phase

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.

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