Preparation of Submicron and Micron Size Cr (IV) Optical Composites

1999 ◽  
Vol 581 ◽  
Author(s):  
L.L. Isaacs ◽  
V. Petricevic ◽  
BaoPing Wang ◽  
Jinpin Ying ◽  
R.R. Alfano
Keyword(s):  
Single Crystals ◽  
Size Distribution ◽  
Sol Gel ◽  
Optically Active ◽  
Ongoing Research ◽  
Active Particles ◽  
Strong Luminescence ◽  
Micron Size ◽  
Doped Materials

ABSTRACTSol - gel technology is used to prepare sub-micron to micron size particles of Chromium (IV) doped materials. These materials show strong luminescence, as single crystals, in the 1-2 μm range. Such materials include; Cr (IV): (Ca2GeO4, Mg2SiO4, LiScGeO4). The optically active particles are dispersed into glassy matrixes to form optical composites. Ongoing research is aimed at, a) reducing the size and the size distribution of the optically active particles, and b) finding suitable matrix materials.

Spherical Zirconia Particles Via Electrostatic Atomization: Fabrication and Sintering Characteristics

1988 ◽  
Vol 121 ◽  
Author(s):  
E. B. Slamovich ◽  
F. F. Lange
Keyword(s):  
Electric Field ◽  
Single Crystals ◽  
Size Distribution ◽  
The Other ◽  
Sintering Behavior ◽  
Space Vehicles ◽  
Electrostatic Atomization ◽  
Zirconium Acetate ◽  
Micron Size ◽  
Sintering Characteristics

From the first recorded investigations by Bosetti in 1745 through G.I. Taylor's[2] work on the “Disintegration of Water Droplets in an Electric Field” in 1964, electrostatic atomization of liquids has been put to use in a variety of applications ranging from crop spraying to the propulsion of space vehicles. Here, we have used electrostatic atomization to form micron size droplets of zirconium acetate which pyrolyze to spherical ZrO2 particles for use in sintering studies. Two ZrO2 powders were fabricated. Both are spherical and of similar size distribution, however, in one, the particles are single crystals, while in the other, the particles are polycrystalline. This work discusses the processing of these different particles, and the relative sintering behavior of powders that are composed of either monocrystalline or polycrystalline particles.

Influence of Ethanolic Plant Extracts on Morphology and Size Distribution of Sol‐Gel Prepared TiO 2 Nanoparticles

2021 ◽  
Vol 6 (16) ◽  
pp. 3958-3968
Author(s):  
Rafael‐Aurelio Rodríguez‐Jiménez ◽  
Yesmin Panecatl‐Bernal ◽  
Jesús Carrillo‐López ◽  
Miguel‐Ángel Méndez‐Rojas ◽  
Anabel Romero‐López ◽  
...  
Keyword(s):  
Size Distribution ◽  
Plant Extracts ◽  
Sol Gel

A NEW ORGANIC/INORGANIC HYBRID WITH HIGH ELECTRORHEOLOGICAL ACTIVITY

2002 ◽  
Vol 16 (17n18) ◽  
pp. 2454-2460 ◽  
Author(s):  
X. P. ZHAO ◽  
X. DUAN
Keyword(s):  
Activation Energy ◽  
Shear Stress ◽  
Necessary Conditions ◽  
Sol Gel ◽  
Root Temperature ◽  
Sedimentation Stability ◽  
Inorganic Hybrid ◽  
Active Particles ◽  
Static Shear

In-situ sol-gel method to prepare colloidal hybrids of surfactant modified polysucchride and titanium oxide has been presented, and experiments indicated these highly ER active particles exhibited a remarkable ER effect. The static shear stress can be up to 37 k Pa (shear rate 5 S -1) under DC field of 4 kV/mm at root temperature, well above that of simple blends of starch and TiO 2. In the meanwhile, temperature dependence and sedimentation stability were also greatly improved. Based on recent experimental facts, we find that dielectric properties and surface (interface) activity are two necessary conditions fulfilling the requirement of high ER activity. Adequate grinding of particles with oil can effectively enhance the shear stress, which may be owed to the decline of the activation energy needed for restructuring. It has provided us a new horizon for preparation of excellent ER materials and further studies should be continued to make.

scholarly journals Ionic Liquids-Containing Silica Microcapsules: A Potential Tunable Platform for Shaping-Up Epoxy-Based Composite Materials?

Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 881
Author(s):  
Ting Shi ◽  
Sébastien Livi ◽  
Jannick Duchet ◽  
Jean-François Gérard
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Diameter Distribution ◽  
Excellent Thermal Stability ◽  
Transmission Electron ◽  
Micron Size ◽  
Phosphonium Ionic Liquid ◽  
One Step ◽  
The One ◽  
First Time

In this work, silica microcapsules containing phosphonium ionic liquid (IL), denoted SiO2@IL, were successfully synthesized for the first time using the one step sol-gel method in IL/H20 emulsion. The morphologies of the obtained micron-size microcapsules, including their diameter distribution, were characterized using dynamic light scattering (DLS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The thermal behavior of these microcapsules and the mass fraction of the encapsulated IL in the silica microcapsules were determined using thermogravimetric analysis, showing an excellent thermal stability (up to 220 °C) and highlighting that an amount of 20 wt.% of IL is contained in the silica microcapsules. In a second step, SiO2@IL microcapsules (1 wt.%) were dispersed into epoxy-amine networks to provide proof of concept of the ability of such microcapsules to act as healing agents as microcracks propagate into the epoxy networks.

Optical and Structural Properties of MeV Erbium Implanted LiNbO3

1993 ◽  
Vol 316 ◽  
Author(s):  
M. Fleuster ◽  
CH. Buchal ◽  
E. Snoeks ◽  
A. Polman
Keyword(s):  
Surface Layer ◽  
Single Crystals ◽  
Structural Properties ◽  
Maximum Concentration ◽  
Solid Phase ◽  
Optically Active ◽  
Layer By Layer ◽  
Warm Up

ABSTRACTLiNbO3 single crystals were implanted with Er ions at 3.5 MeV with fluences up to 3*1016 Er/cm2 and subsequently annealed at 1060°C. The warm-up rate of the sample determines whether the implanted, amorphized surface layer recrystallizes via columnar or via layer-by-layer solid phase epitaxial (SPE) growth. The maximum concentration of optically active Er ions is determined to be 0.18 at.%.

Size distribution and magnetic behavior of lead inclusions in silicon single crystals

1997 ◽  
Vol 81 (5) ◽  
pp. 2148-2152 ◽  
Author(s):  
K. Milants ◽  
J. Verheyden ◽  
T. Barancira ◽  
W. Deweerd ◽  
H. Pattyn ◽  
...  
Keyword(s):  
Single Crystals ◽  
Size Distribution ◽  
Magnetic Behavior

Synthesis and Characterization of Pd/Ag/SiO2 Nano-Composite Materials

2017 ◽  
Vol 726 ◽  
pp. 204-209 ◽  
Author(s):  
Jing Yang ◽  
Bao Song Li ◽  
Zhi Tong ◽  
Rui Hua Mu
Keyword(s):  
Zeta Potential ◽  
Size Distribution ◽  
Sol Gel ◽  
Linear Structure ◽  
Nitrogen Atmosphere ◽  
Molar Ratio ◽  
Powder Materials ◽  
X Ray Diffraction ◽  
Silica Network

Pd/Ag/SiO2 sols and powder materials were prepared by adding AgNO3 and Pd (NO3)2·2H2O into a methyl-modified silica sol. Tetraethylorthosilicate and methyltriethoxysilane were used as the silica precursor for the sol-gel reaction. The obtained SiO2 sols and powder materials were characterized by sol particle size distribution, zeta potential analysis, UV-Vis spectra, Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) measurement. It was found that most of the particle sizes of the prepared Pd/Ag/SiO2 sols are about 2~10 nm with narrow size distribution. The zeta potential of Pd/Ag/SiO2 sol with Pd/Ag molar ratio of 7.5/2.5 presents the highest value. The FTIR analysis substantiates that the Si-CH3 groups exist in the silica network and the formed Pd/Ag/SiO2 sol particles possess linear structure. XRD characterization indicates that the Pd2+ and Ag+ in the Pd/Ag/SiO2 materials had be reduced to Pd0 and Ag0, respectively, after annealed in a nitrogen atmosphere at 350°C.

scholarly journals Novel Gd3+-doped silica-based optical fiber material for dosimetry in proton therapy

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
C. Hoehr ◽  
A. Morana ◽  
O. Duhamel ◽  
B. Capoen ◽  
M. Trinczek ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Proton Therapy ◽  
Bragg Peak ◽  
Light Emission ◽  
Sol Gel ◽  
Fiber Material ◽  
Beam Current ◽  
Strong Luminescence ◽  
The University

Abstract Optical fibers hold promise for accurate dosimetry in small field proton therapy due to their superior spatial resolution and the lack of significant Cerenkov contamination in proton beams. One known drawback for most scintillation detectors is signal quenching in areas of high linear energy transfer, as is the case in the Bragg peak region of a proton beam. In this study, we investigated the potential of innovative optical fiber bulk materials using the sol-gel technique for dosimetry in proton therapy. This type of glass is made of amorphous silica (SiO$${}_{2}$$ 2 ) and is doped with Gd$${}^{3+}$$ 3 + ions and possesses very interesting light emission properties with a luminescence band around 314 nm when exposed to protons. The fibers were manufactured at the University of Lille and tested at the TRIUMF Proton Therapy facility with 8.2–62.9 MeV protons and 2–6 nA of extracted beam current. Dose-rate dependence and quenching were measured and compared to other silica-based fibers also made by sol-gel techniques and doped with Ce$${}^{3+}$$ 3 + and Cu$${}^{+}$$ + . The three fibers present strong luminescence in the UV (Gd) or visible (Cu,Ce) under irradiation, with the emission intensities related directly to the proton flux. In addition, the 0.5 mm diameter Gd$${}^{3+}$$ 3 + -doped fiber shows superior resolution of the Bragg peak, indicating significantly reduced quenching in comparison to the Ce$${}^{3+}$$ 3 + and Cu$${}^{+}$$ + fibers with a Birks’ constant, k$${}_{B}$$ B , of (0.0162 $$\pm $$ ± 0.0003) cm/MeV in comparison to (0.0333 $$\pm $$ ± 0.0006) cm/MeV and (0.0352 $$\pm $$ ± 0.0003) cm/MeV, respectively. To our knowledge, this is the first report of such an interesting k$${}_{B}$$ B for a silica-based optical fiber material, showing clearly that this fiber presents lower quenching than common plastic scintillators. This result demonstrates the high potential of this inorganic fiber material for proton therapy dosimetry.

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