High-frequency dielectric study of the dynamics of (KBr)1?x (KCN) x mixed crystals

1988 ◽  
Vol 70 (4) ◽  
pp. 485-490 ◽  
Author(s):  
J. F. Berret ◽  
P. Doussineau ◽  
A. Levelut ◽  
W. Sch�n
Keyword(s):  
High Frequency ◽  
Mixed Crystals ◽  
Dielectric Study

Dynamics of water-containing sodium bis(2-ethylhexyl)sulfosuccinate (AOT) reverse micelles: A high-frequency dielectric study

1996 ◽  
Vol 54 (1) ◽  
pp. 993-996 ◽  
Author(s):  
M. D’Angelo ◽  
D. Fioretto ◽  
G. Onori ◽  
L. Palmieri ◽  
A. Santucci
Keyword(s):  
High Frequency ◽  
Reverse Micelles ◽  
Dielectric Study ◽  
Aot Reverse Micelles

Growth and high frequency dielectric study of pure and thiourea doped KDP crystals

2007 ◽  
Vol 42 (11) ◽  
pp. 1110-1116 ◽  
Author(s):  
S. S. Hussaini ◽  
N. R. Dhumane ◽  
G. Rabbani ◽  
P. Karmuse ◽  
V. G. Dongre ◽  
...  
Keyword(s):  
High Frequency ◽  
Dielectric Study ◽  
Kdp Crystals

scholarly journals High-frequency dielectric study of proustite crystals Ag3AsS3

2014 ◽  
Vol 572 ◽  
pp. 012019
Author(s):  
V A Bordovsky ◽  
N Yu Gunia ◽  
R A Castro
Keyword(s):  
High Frequency ◽  
Dielectric Study

Application of High Frequency Dielectric Spectroscopy for the Assessment of Durability of Adhesively Bonded Composite Structures

1999 ◽  
Author(s):  
P. Boinard ◽  
R. A. Pethrick ◽  
W. M. Banks
Keyword(s):  
Mechanical Properties ◽  
Carbon Fibre ◽  
High Frequency ◽  
Composite Structures ◽  
Adhesive Layer ◽  
Dielectric Study ◽  
Adhesively Bonded ◽  
Wide Range ◽  
The Matrix ◽  
Bonded Composite

Abstract Composites materials, especially adhesively bonded structures are being used in a wide range of applications, including situations where they become exposed to high levels of moisture. Ingress of moisture into a polymeric material will in general lead to changes in its mechanical properties usually associated with plasticisation effects. In bonded composite structures, water ingress can influence not only the mechanical properties of the matrix but also those of the matrix-fibre and adhesive-adherent interfaces. Over the last ten years, the application of high-frequency dielectric techniques to the characterisation of the integrity and durability of adhesively bonded metallic structures has been extensively investigated by the coauthors. In general, a bonded structure resembles a wave-guide in which the adhesive layer is the dielectric. Changes in the characteristics as a function of time of exposure to the environment can be used to monitor the ageing of such structures. This paper discusses the application of the principles to the study of carbon fibre reinforced plastics (CFRP) adhesively bonded composite structures. Carbon fibre is in general less conductive than aluminium material. However, it is sufficiently conductive to sustain the propagation of high-frequency dielectric signals. The effect of changes in the surface alignment and subsequent bulk orientation of carbon fibres on the dielectric propagation has been investigated. The ingress of moisture in the raw materials and in the joint structure is presented. The high-frequency time domain response (TDR) analysis allows the integrity of the structure to be explored and a good correlation is shown between TDR analysis and gravimetric results. This study indicates that the success obtained in the application of high frequency dielectric measurements to adhesively bonded aluminium structures is also applicable to CFRP bonded structures. The dielectric study not only indicates a new way to assess the state of such a structure but is also producing new insights into the application of TDR measurement to non-isotropic materials.

The Microstructure of Steatite (Protoenstatite)

1985 ◽  
Vol 43 ◽  
pp. 236-237
Author(s):  
W. E. Lee ◽  
A. H. Heuer
Keyword(s):  
High Frequency ◽  
Glass Ceramics ◽  
Magnesium Silicate ◽  
Beam Current ◽  
Glassy Matrix ◽  
Angle Of Incidence ◽  
X Ray ◽  
Mechanical And Electrical Properties ◽  
Argon Ions ◽  
High Temperature Polymorph

IntroductionTraditional steatite ceramics, made by firing (vitrifying) hydrous magnesium silicate, have long been used as insulators for high frequency applications due to their excellent mechanical and electrical properties. Early x-ray and optical analysis of steatites showed that they were composed largely of protoenstatite (MgSiO3) in a glassy matrix. Recent studies of enstatite-containing glass ceramics have revived interest in the polymorphism of enstatite. Three polymorphs exist, two with orthorhombic and one with monoclinic symmetry (ortho, proto and clino enstatite, respectively). Steatite ceramics are of particular interest a they contain the normally unstable high-temperature polymorph, protoenstatite.Experimental3mm diameter discs cut from steatite rods (∼10” long and 0.5” dia.) were ground, polished, dimpled, and ion-thinned to electron transparency using 6KV Argon ions at a beam current of 1 x 10-3 A and a 12° angle of incidence. The discs were coated with carbon prior to TEM examination to minimize charging effects.

Simulations of high-resolution images of amorphous silicon films

1986 ◽  
Vol 44 ◽  
pp. 544-545
Author(s):  
G. Y. Fan ◽  
J. M. Cowley
Keyword(s):  
Electron Microscope ◽  
High Frequency ◽  
Fourier Transformation ◽  
Amorphous Materials ◽  
Low Frequency ◽  
Chromatic Aberration ◽  
Structure Information ◽  
Frequency Components ◽  
High Resolution Images ◽  
Spatial Frequency Spectrum

It is well known that the structure information on the specimen is not always faithfully transferred through the electron microscope. Firstly, the spatial frequency spectrum is modulated by the transfer function (TF) at the focal plane. Secondly, the spectrum suffers high frequency cut-off by the aperture (or effectively damping terms such as chromatic aberration). While these do not have essential effect on imaging crystal periodicity as long as the low order Bragg spots are inside the aperture, although the contrast may be reversed, they may change the appearance of images of amorphous materials completely. Because the spectrum of amorphous materials is continuous, modulation of it emphasizes some components while weakening others. Especially the cut-off of high frequency components, which contribute to amorphous image just as strongly as low frequency components can have a fundamental effect. This can be illustrated through computer simulation. Imaging of a whitenoise object with an electron microscope without TF limitation gives Fig. 1a, which is obtained by Fourier transformation of a constant amplitude combined with random phases generated by computer.

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