TEM visualization of surface replicated acid and base catalyzed sol-gel glasses

1986 ◽  
Vol 44 ◽  
pp. 448-449
Author(s):  
George C. Ruben ◽  
Merrill W. Shafer
Keyword(s):  
Elevated Temperatures ◽  
Sol Gel ◽  
Basic Medium ◽  
Glass Transition Point ◽  
Structural Space ◽  
Acid And Base ◽  
Organometallic Precursors ◽  
New Processing ◽  
Gel Glasses ◽  
Physical Phenomena

Traditionally ceramics have been shaped from powders and densified at temperatures close to their liquid point. New processing methods using various types of sols, gels, and organometallic precursors at low temperature which enable densificatlon at elevated temperatures well below their liquidus, hold the promise of producing ceramics and glasses of controlled and reproducible properties that are highly reliable for electronic, structural, space or medical applications. Ultrastructure processing of silicon alkoxides in acid medium and mixtures of Ludox HS-40 (120Å spheres from DuPont) and Kasil (38% K2O &62% SiO2) in basic medium have been aimed at producing materials with a range of well defined pore sizes (∼20-400Å) to study physical phenomena and materials behavior in well characterized confined geometries. We have studied Pt/C surface replicas of some of these porous sol-gels prepared at temperatures below their glass transition point.

Spectroscopic Investigations of Neptunium's and Plutonium's Oxidation States in Sol-Gel Glasses as a Function of Initial Valence and Thermal History

1996 ◽  
Vol 465 ◽  
Author(s):  
N. A. Stump ◽  
R. G. Haire ◽  
S. Dai
Keyword(s):  
Oxidation State ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Sol Gel ◽  
Solidification Process ◽  
Silica Matrix ◽  
Oxidation States ◽  
Temperature Spectra ◽  
Gel Glasses ◽  
Starting Solutions

ABSTRACTSeveral oxidation states of neptunium and plutonium, Pu(III), Pu(IV), Pu(VI), Np(IV), Np(V), and Np(VI), were studied in glasses prepared by a sol-gel technology. The oxidation state of these actinides in the sol-gel product was examined by absorption spectroscopy after solidification, aging, and thermal treatment. The oxidation state of the actinides in the starting solutions was essentially maintained through the solidification process of the silica matrix. However, during densification and removal of residual solvents at elevated temperatures, both actinides converted eventually to their tetra valent states while in the different sol-gel products. This finding is in accord with reports that tetravalent states of plutonium and neptunium are acquired in glass products prepared by dissolution of the actinide in molten glasses. Comparisons between room temperature spectra obtained from neptunium and plutonium in heated sol-gel products and from molten glass products showed subtle differences that can be related to the metal ion's environments.

Photopatterning of hybrid sol–gel glasses: generation of volume phase gratings under visible light

2004 ◽  
Vol 398 (1-3) ◽  
pp. 151-156 ◽  
Author(s):  
M. Feuillade ◽  
C. Croutxé-Barghorn ◽  
L. Mager ◽  
C. Carré ◽  
A. Fort
Keyword(s):  
Visible Light ◽  
Sol Gel ◽  
Volume Phase ◽  
Gel Glasses

Bioencapsulation in Sol-Gel Glasses

1998 ◽  
Vol 519 ◽  
Author(s):  
L. Bergogne ◽  
S. Fennouh ◽  
J. Livage ◽  
C. Roux
Keyword(s):  
Sol Gel ◽  
Porous Silica ◽  
Silica Matrix ◽  
Whole Cells ◽  
The Past ◽  
Wide Range ◽  
Activity Of Enzymes ◽  
Gel Glasses ◽  
Micro Organisms

AbstractBioencapsulation in sol-gel materials has been widely studied during the past decade. Trapped species appear to retain their bioactivity in the porous silica matrix. Small analytes can diffuse through the pores allowing bioreactions to be performed in-situ, inside the sol-gel glass. A wide range of biomolecules and micro-organisms have been encapsulated. The catalytic activity of enzymes is used for the realization of biosensors or bioreactors. Antibody-antigen recognition has been shown to be feasible within sol-gel matrices. Trapped antibodies bind specifically the corresponding haptens and can be used for the detection of traces of chemicals. Even whole cells are now encapsulated without any alteration of their cellular organization. They can be used for the production of chemicals or as antigens for immunoassays.

Structural Stability of Azurin Encapsulated in Sol-Gel Glasses: A Fluorometric Study

2004 ◽  
Vol 30 (3) ◽  
pp. 205-214 ◽  
Author(s):  
Massimo Bottini ◽  
Almerinda Di Venere ◽  
Lutz Tautz ◽  
Alessandro Desideri ◽  
Paolo Lugli ◽  
...  
Keyword(s):  
Structural Stability ◽  
Sol Gel ◽  
Gel Glasses ◽  
Fluorometric Study

scholarly journals Neutron diffraction study of antibacterial bioactive calcium silicate sol-gel glasses containing silver

2017 ◽  
Vol 8 (4) ◽  
pp. 364-371 ◽  
Author(s):  
Daniela Carta ◽  
Julian R. Jones ◽  
Sen Lin ◽  
Gowsihan Poologasundarampillai ◽  
Robert J. Newport ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Diffraction Study ◽  
Calcium Silicate ◽  
Sol Gel ◽  
Neutron Diffraction Study ◽  
Gel Glasses

Small Angle Neutron Scatitering Study of Sol-Gel Glasses

1989 ◽  
Vol 166 ◽  
Author(s):  
P. Wiltzius ◽  
S. B. Dierker
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Structure Factor ◽  
Small Angle Neutron Scattering ◽  
Sol Gel ◽  
Scattering Data ◽  
Length Scales ◽  
Internal Interface ◽  
Porous Glasses ◽  
Gel Glasses

ABSTRACTWe present small angle neutron scattering data of porous glasses. Analysis of the structure factor shows that the morphology on length scales between 30 A and 800 A depends on fabrication procedures. Fast gelation leads to a clumpy glass, whereas slow gelation produces a random smooth internal interface.

Optic and Piezoelectric Coupling in the Sol-Gel PLZT Electroceramics

2012 ◽  
Vol 730-732 ◽  
pp. 129-134
Author(s):  
Lucjan Kozielski ◽  
Malgorzata Plonska
Keyword(s):  
Uv Light ◽  
Sol Gel ◽  
Light Illumination ◽  
Piezoelectric Effects ◽  
Piezoelectric Coupling ◽  
Wireless Device ◽  
Organometallic Precursors ◽  
Gain Adjustment ◽  
Piezoelectric Transformers ◽  
Sintering Method

PZT ceramic system with presence of La contents, have been proposed and prepared using sol gel sintering method for practical application of photostriction, which is the superposition of photovoltaic and piezoelectric effects. Such a ceramics produced by conventional mixing oxide method does not exhibit photostrictive properties due to the defects and inhomogeneous distribution of grains and pores. In this study, an investigated lanthanium(III) doped PZT ceramics were obtained by sol-gel technique from the organometallic precursors. It was found that fabricated material were effective in the enhancement of photovoltaic and photostrictive properties. Consequently, lanthanium influence deviation of piezoelectric parameters were studied as a function UV light illumination. For the determination lighting dependancy of the transformation parameters the resonant and antiresonant method was implemented. The improved Piezoelectric Transformer structure successfully changed gain characteristics proportionally to light intensity. The authors invention of a light driven output gain adjustment in Piezoelectric Transformers (PT) yields a novel “smart” multifunctional wireless device. This new created application area can be utilized in self-adopting shutters in photo cameras due to improved sensitivity to surrounding illumination conditions.

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